Senescence Back and Forth 3031322754, 9783031322754

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Urs Nydegger Thomas Lung

Senescence Back and Forth

Senescence Back and Forth

Headstand, 1991 Bronze by Marcel Perincioli (1911–2005) Posture on a granite cube from Vals (Swiss Alps) Photo with Sony Camera 7 III, copyright by wpw 2022

Urs Nydegger · Thomas Lung

Senescence Back and Forth

Urs Nydegger Medical Laboratory Dr. Risch Liebefeld, Switzerland

Thomas Lung Medical Laboratory Dr. Risch Buchs, Switzerland

ISBN 978-3-031-32275-4 ISBN 978-3-031-32276-1 (eBook) https://doi.org/10.1007/978-3-031-32276-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

This book is dedicated to Damiano Castelli and Gert Risch with their paying tribute to the Red Cross and Patient Care from the Laboratory Bench

Preface

This book is about the lifelong aging of humans. The basic biochemical and genetic mechanisms remain ill-known and differ among individuals. We start out exploring plant and animal kingdoms to answer questions about human aging needs for understanding. First, we scrutinize time running out and what “normal” means with impacts on the genome, protein half-lives, and function. Aging goes beyond biochemical skids treated by drugs developed to downregulate senescence; albeit early diagnosis with standard medical lab assays, here addressed, sheds light with a focus on basic research. Tools like machine learning, and DNA technology, e.g., genomics, have already provided surprising insights. The chapters then turn around the senescence of the entire organism based on variable aging of single organs embedded in neuronal networks. Psychological stress factors, dementia opposed to vigilance, and the distinction of aging from the overt disease are contrasting in humans and are opposed in the book. Senescence, seen as a one-way track, may be reverted into rejuvenation—possible by insights into the senescence of the immune system and genomic approaches. Risk management in health insurance finds important clues. The topics address life expectancy beyond the centenarian age group; nursing caretakers and the pharmaceutical industry are invited to understand what’s happening in seniors to render their geriatric population fit or frail. Bern, Switzerland Hohenems, Austria

Urs Nydegger Thomas Lung

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Acknowledgments

The authors are indebted to their wives, who experienced long absences from the home of Urs and Thomas while writing this book. The probands of the SENIORLABOR study showed a great interest in the results and were inspiring for a study on senescence. Without their participation, senescence would have meant to the authors just old age! The Risch brothers, Lorenz Risch, and Martin Risch took up without hesitation the idea from their father, Gert Risch, to closely look at reference intervals of most routine med lab assays. Without their enthusiasm, senescence was nothing but a side track of laboratory medicine. Next to the list of acknowledgments, our study nurse, Mrs. Elisabeth Lenggenhager, was interested in the well-being of probands and devoted hours of her time to conversations with them and to build up a proband community. Pasquale Di Cesare, our intellectual companion as an ethical person and among the medical staff of the University Hospital Inselspital Bern, prominently Zeno Stanga, advised for the study. Birgit Wessling and Simone Inderbizin were active secretaries backed by Madeleine Lehmann to make the study running at the beginning. Lately, younger colleagues joined in SENIORLABOR, Benjamin Sakem, and Andreas Hemmerle being the most active, with Andreas Hemmerle in charge of Figure drawing and editorial formatting of the whole manuscript. Andres Nydegger, dipl.Arch. ETH, Zurich, Switzerland, for his initial ethical contributions. The Gastroenterology Clinic of Jean-Pierre Gutzwiller and Andreas Cerny of the Epatocenro Moncucco, Lugano, opened

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Acknowledgments

the doors to hepatic senescence. Werner P. Wegmüller is WPW, the photographer. Uschi Schwärzler, the mosaic artist, Mosaico del Sole, Austria. The editorial precision provided by SPRINGER NATURE is invaluable. The contribution of the Museum for Natural History, Bern, Switzerland is kindly acknowledged.

Contents

1

Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Senescence is Time Dependent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 The Eranos Lecture of Monte Verità . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Senescence on the Move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 In Pursuit of Wisdom—What’s Next . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Boon and Bane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 1 2 3 7 8 13

2

Genetics—The Language of Proteomics . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Manipulate the Back and Forth Meaning with Genomics . . . . . . . 2.2 Gene Scissor Technology—CRISPR . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15 15 24 25

3

Senescence in Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Plants, Good Examples for Senescence Information . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27 27 35

4

Senescence in Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Zoological Senescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37 37 43

5

Rejuvenation/Regeneration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 A Button off May Turn on Something Else . . . . . . . . . . . . . . . . . . . 5.2 Senescence and Religion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Immortality at Its Best . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Suicide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Organ Transplants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 Artificial Organs (Distinguish Cellular Organs from Artificial Material) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7 3D Bioprinting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45 45 47 47 50 55 55 56

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5.8 Life Transplants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9 Xenotransplantation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

58 59 60

6

Overlap Senescence/Chronic Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Ambiguity Between Two Different Medical Conditions . . . . . . . . 6.2 Examples of Senescence Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1 Georgia Centenarian Study . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2 Yale Y-Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3 Centenarians in Iowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.4 Banner Alzheimer’s Institute . . . . . . . . . . . . . . . . . . . . . . . . 6.2.5 The Baltimore Longitudinal Study of Aging (BLSA) . . . . 6.2.6 PolSenior 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.7 DO-HEALTH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.8 Seniorlabor Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

61 61 65 65 66 66 66 66 67 67 68 68

7

Mosaic of Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Manifold Senescence in the Same Individual . . . . . . . . . . . . . . . . . 7.2 Repair/Rejuvenation of Senescent/Aging Organs . . . . . . . . . . . . . . 7.3 The Senescing Memory and How to Measure Memory . . . . . . . . . 7.4 Type Hunter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Bigger Brains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Heart and Vascular Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Lungs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8 Pleura . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.9 Liver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Pancreas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.11 Intestine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.12 Diversity at Its Best . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

69 69 72 78 83 84 84 84 85 85 86 86 87 87

8

Remaining Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Look into the Rear—View Mirror . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 What the Future Might Hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 What We Know Up to Now . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 What the Future Will Show . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

89 89 93 94 94 94

9

Medical Laboratory Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1 Fire and Brimstone Sermon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 What the Future Will Show . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 Age Pervasiveness of Frequent Diseases . . . . . . . . . . . . . . . . . . . . . 9.3.1 Health Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4 Metabolic Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5 Aging, Hallmarks, and Biomarkers . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 Laboratory Assays as Biomarkers of Aging . . . . . . . . . . . . . . . . . .

95 95 99 101 101 104 105 108

Contents

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9.6.1 Hematological and Related Aspects . . . . . . . . . . . . . . . . . . 9.7 Ferritin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.8 Glucose Metabolism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.9 Reference Intervals Found in the SENIORLABOR Study . . . . . . 9.10 The Complement System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

110 115 115 116 118 120

10 Geroprotector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 Technical and Medical Possibilities . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 Agree on Desired Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 Immediate Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

123 123 125 126 128

11 Hannibal Ante Portas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 11.1 Hopeful or Dangerous Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

About the Authors

Urs Nydegger, M.D. Born in 1941 in Bern, Switzerland. For the Study of Medicine, he attended the University of Bern. In 2022, the author concludes a 12-year parttime engagement as a medical consultant for the Medical Laboratories Dr. Risch, a Liechtenstein-based enterprise dedicated to excellence in clinical laboratory testing. Nydegger helped to establish neglected reference intervals of lab tests for the elderly. Alumnus and Professor of the University of Bern, where he was Head of the Blood Bank (1985–2001) and Medical Research in the Cardiovascular Department (up to 2006). Clinical education: University Hospitals of Bern and Geneva; Boards of Internal Medicine FMH and Haematology FMH. An alumnus of Harvard Medical School, Boston, MA, USA, at the Robert B. Brigham Hospital (1976–1978). U. Nydeggers’s scientific contributions peak with a Citation Classic on the detection of circulating immune complexes and with ABO-histo-blood type incompatible transplantation; the most frequently cited studies pertain to the biocompatibility of artificial organs. Dr. rer. nat. Thomas Lung Born in 1966 in Bregenz, Austria. Lung became interested in the study of senescence while at the University of Innsbruck, the Institute for Biomedical Aging Research, Austrian Academy of Sciences. Since then, he has worked in Switzerland as a Laboratory Manager for Clinical Immunology, FAMH, in two private med lab service institutions. He remained interested in reference intervals of med lab tests differing according to patients’ age. The SENIORLABOR study brought his interest to projects sponsored by Dr. Risch Laboratories and attended, among others, by Nydegger. The results include several peer-reviewed original scientific reports with Lung as the first author. A large part of these papers, not always referenced in our book, take part as a basis for the relevance of senescence research in the booming field of laboratory medicine. When time permits in his routine laboratory work, Lung has extensive engagement as a speaker in postgraduate teaching.

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List of Figures

Fig. 1.1

Fig. 1.2

Fig. 2.1

With FAMH standards, no less than the results of 120 samples must be plotted on a graph. The ideal distribution appears as a bell-shaped curve of which the middle top maximum depicts a maximal probability that the following sample will display. The exposure variable can be compared in cross-sectional studies; data collection and clinical outcome can be analyzed simultaneously, thus describing characteristics of the sample with other study associations of interest (biostatistics). FAMH (FOEDERATIO ANALYTICORUM MEDICINALIUM HELVETICUM): The medical laboratories of Switzerland . . . . . Swoop of Birds. Bird Observers may recognize the species of birds of prey by the flight path they pursue while nose dipping down to a victim: most species dip down straight down (left part of the figure) while others, exceptions, make a stopover to ascertain whether it’s worth it (right part of the figure). Bayes theorem scrutinizes whether all flight patterns are the same and mathematically argues that exceptions from a p-value < 0.005 may also be normal . . . . DNA ladder with its rungs. The rungs of the DNA ladder consist of pairs of four chemicals, called bases, abbreviated A, C, T, G. Its backbone is a monotonous string of sugars and phosphates. The information content resides in those bases arranged within the interior, where A pairs with T and C always pairs with G. This is the code of life. Science and mystery join when Bill Clinton (*1946) tells Francis Collins (*1950), “we are learning the language in which God created life”. Furthermore, we are learning to manipulate the sequence of DNA components, thus changing the genome. Single-cell genomics is at the doorstep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Fig. 2.2

Fig. 2.3

Fig. 3.1

Fig. 3.2 Fig. 3.3

Fig. 3.4

List of Figures

Helicase induced DNA Split. DNA histones and RNA histones, often associated with polymerases, are enzymes that provide structural support to a chromosome. They do this by unwinding the parental DNA. Helicase may be seen as a motor resisting the base-pairing energy of the DNA. That DNA molecules, even the very long ones, can fit into the cell nucleus, they have to wrap around complexes of histone proteins, giving the chromosome a more compact shape. Some variants of histones are associated with the regulation of gene expression, and many of us believe that this has something to do with senescence, impacting the life clock. The accelerated aging disease Werner syndrome patients showed dysbalanced helicase activity, suggesting histones’ role in senescence. Quae veritati operam dat, incomposita sit et simplex (Seneca, letter 40: The style we have to apply here must be straightforward and simple)! . . . . . . . . . . . . . . . . . . Genomics as the backbone of Proteomics. The structure and function of proteins are programmed in detail by DNA sequences. This graph roughly depicts the relationship between genomics and proteomics. Each protein analysis depends on 100% from DNA programming with RNA to the ribosomal assembly of selected amino acids . . . . . . . . . . . Chimonanthus praecox (Wintersweet). One may assume that wintersweet tries to forestall senescence by blooming early on (Photo made by U. Nydegger) . . . . . . . . . . . . . . . . . . . . . Old Olive Tree. About 700-year old Olive tree in Cuglieri (Sardegna, Italy) (Photo with Copyright of WPW) . . . . . . . . . . . . Leaf Senescence. Once summer is over, chlorophyll (C55 H72 O5 N4 Mg) loses magnesium and changes the light absorption spectrum going from green to yellow (or red). The foliage season in New England, USA, is marvelous to the observer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bonsai—a Maple, still young, about 20 years. Separated from its natural environment, cultivated in our garden in a suburb of Bern, Switzerland, follows seasonal changes (taken here in march 2022, left and may, right). The Asian cultures have known Bonsai cultures for over 1000 years. The idea of growing a Bonsai is to create a miniaturized but realistic representation of nature in the form of a tree. The seasonal foliage of the parent tree is maintained. Bonsais are genetically identical to their grown-up version; Bonsais are non-dwarfed plants—any tree species can be used to grow one (Photo WPW) . . . . . . . . . . . . . . . . . . . . . . . . . . .

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List of Figures

Fig. 3.5

Fig. 4.1

Fig. 4.2

Fig. 4.3

Spruce and maple wood join together to build a Rémy violin. The ribs and back are maples, and the bout is pine. The best woods, especially for the plates, have been seasoned for many years in large wedges, and the seasoning process continues indefinitely after the violin has been made (Photo by U. Nydegger) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Caenorhabditis elegans, a small nematode. The pioneer in long life—extension of senescence at its best provides a tool in the research lab. The authors remember the burst of research articles starting around 1980 when the genetics of this free-living worm became known, largely confirmed with ever-more precise genomic techniques. One can now override senescence in these animals to extend their survival by a factor of two. Caenorhabditis elegans provides a reliable system to study various features, even among primates, because of its genetic tractability and invariant, compact nervous system (~300 neurons) that is known at the level of DNA sequencing. In addition, despite (and perhaps: because of) its compact nature, the nematode nervous system possesses a high level of conservation with mammalian systems . . . . . . . . . . . . . . . . . . . Parrots are intelligent and long-lived birds. Psittaciformes. Parrots. Subclass Neornithes, Class Aves. Order 22. This parrot with a stout beak has an upper mandible movable on the skull’s frontal bone, which lets him articulate words like humans. Parrots enjoy a long life (K¯ak¯ap¯o: 40–80 years). The gerontology of psittacines could reveal important insights into human senescence. Recent literature explores senescence in these birds. Stuffed bird (Ara chloropterus), Collection of the Natural History Museum Bern, Switzerland (NMBE) (Photo by Mrs. Nelly Rodriguez) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sphinx. An old Egyptian Sphinx consists of a human head on a lion’s torso, thus combining human insights with animal force. Other statues of ancient Egypt connect humans and animals—the most impressive to the authors is the queen Tawaret (664–610 BC) from the 26th dynasty of the reign of Psametik (Photo by U. Nydegger) . . . . . . . . . . . . .

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Fig. 5.1

Fig. 5.2

Fig. 6.1

Fig. 7.1

List of Figures

Facial stop of senescence. Aesthetic plastic surgery (i.e., cosmetic surgery) is a subspecialty of general surgery which takes advantage of biochemical insights into parts of the human body. It refers to procedures that improve the appearance of the face and body and helps severely wounded patients. Methods include abdominoplasty, breast augmentation, breast reduction, eyelid surgery, nose reshaping (rhinoplasty), facelift and removal, and addition of autologous fat. Plastic surgery draws its advances from other fields of medicine, e.g., transfusion, alloand, lately, xenotransplantation. Graft rejection is rarely a problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Senescence is a multifactorial event. Telomere damage, epigenetic dysregulation, DNA breaks, and mitochondrial stress are primary drivers of damage in aging. Several of these drivers of damage can induce senescence. Senescence can, in turn, drive the consequential aging hallmarks in response to damage: stem cell exhaustion and chronic inflammation. Other reactions to damage, such as proteostasis dysfunction and nutrient signaling disruption, are also integrally linked with the senescence response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Smoker. Werner Otto Leuenberger (1932–2009), a Member of the Berne Avantgarde Artists, often showing up with a cigarette, impressively depicts smoke (upper right corner of the painting), oil on canvas 1981, 100 × 80 cm (Copyright with the authors) . . . . . . . . . . . . . . . . . . . . . . . . . . Mosaic with title Star of Blues. Closely set, variously colored, small pieces of glass and beads. The human body resembles a mosaic in which each stone pursues its own senescence. Imagine the differences in histology and metabolism between organs such different as the brain and the liver. The gut endothelial cells are destroyed/ rebuilt within hours—hepatocytes and different so, brain and nerve cells stay there much longer (Copyright from Uschi Schwärzler, mosaic artist) . . . . . . . . . . . . . . . . . . . . . .

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List of Figures

Fig. 7.2

Fig. 7.3

Fig. 7.4

Fig. 7.5

Fig. 7.6

Fig. 8.1

Each organ composing a human body features its own senescence. Exposure of each organ to stress, wear, and tear differs between organs. Guts never end working and are under neurological control of the Nervus vagus, an autochthonous nerve we do not control. The parasympathetic nervous system is a division of the nervous system that primarily modulates visceral organs such as guts and glands. The parasympathetic system is one of two antagonistic sets of nerves of the autonomic nervous system, in this ante posterior sketch imagined by Th. Lung, the Nervus vagus, the abundant abdominal lymphatic system, and the urinary apparatus are not shown . . . . . . . . . . . . . Human organs with their sandglass. The human body contains multiple alarm clocks, emblematized on this teaching slide to pertinent organs. The fastest one rings first, and the aging of the whole organism pushes frailty forward. Acknowledging such a system, geriatricians and caretakers can focus treatment and geroprotecting measures accordingly. (Imagined by A. Hemmerle) . . . . . . . . . . . Different Organs age with different Rhythm—Example: Liver. As seen in the example of the liver, a whole array of senescent changes seen by cytological and tissular means are possible. The fatty liver, the fibrotic liver, the liver defending against infection (chemotaxis), the intracellular complement components (complosome), or the leukocyte infiltrates—either as single events or in a row . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Deaf buddha. The twelfth Venerable Sakyamuni: those who only know the ear-picker knows the deaf Buddha, although there are right and wrong words, go in on the left and go out on the right. (An ancient Chinese text on Buddha cleaning his ears…, passers-by, who don’t know him, judge him as deaf and dumb, but he continues to ignore them and let the rumors go in on one ear and out in the other.) Courtesy: Janice Fuhrer . . . . . . . . . . . . . Alzheimer’s Patient Lost in Reverie. This ‘Homme aux Champignons’, the title given by its artist, the Swiss painter Samuel Buri (*1935), depicts a transcendent human upper body and a head resembling a mushroom we here conceive as seen by disoriented patients of Alzheimer’s Disease (Serigraphy 1/9, property of U. Nydegger) . . . . . . . . . . . . . . . . . . Older men in a Sardinian Village (Italy) surrounding Central Square 1987. Photo: Copyright by wpw . . . . . . . . . . . . . .

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Fig. 9.6

List of Figures

Waterfalls’ bends waterflows time. Example of a painting with the topic time, memory, and flow—back and forth line. Sigrun Lung’s (*1943) Niagara Falls. Oil painted on canvas (2007). The viewer recognizes that time is an eternal cycle, like the continuous cycle of water that follows the flow of Niagara Falls . . . . . . . . . . . . . . . . . . . . . . The FAMH wheel of specialties. From Clinical Chemistry with the often ordered ferritin, Immunology with autoantibodies, Microbiology clearing infections, and Hematology with platelets (thrombocytes). Each field is now increasingly governed by genetic exams . . . . . . . . . . . . . . Stamp of Karl Landsteiner. From U. Nydegger’s stamp collection “100. anniversary Dr. Karl Landsteiners.”, Discoverer of ABO Blood Types (Austria stamp number 1296, Austria Netto Catalogue 1968) . . . . . . . . . . . . . . . . . . . . . . Gross blend of frequent diseases and age groups of their predilection. The blurb positions are based on long-term international clinical observations; robust odds ratios are unavailable. Most of the depicted diseases occur at any age—the blurb positions denote a proclivity. We believe that individuals may have reached decency for which they are sheltered from a distinct diagnosis. The death reason recorded on statistical files is not reliable (Copyright from KARGER, Basel, Switzerland) . . . . . . . . . . . . . Alignment of elementary medical laboratory tests. A good opening of the data with the SENIORLABOR study would be predicting morbidity, if not mortality, with a set of simple med lab assays (Copyright from KARGER, Basel, Switzerland) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What innate immunity adds up. This figure lists numerous immunology tests which are currently (the year 2022) neglected and may reveal the large informative potential for certain diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Seniorlabor study: age of probands. The participants of the SENIORLABOR Study, starting in 2008, were recruited by newspaper ads, chess clubs, mountaineering persons, and mouth-to-mouth propaganda. They were taken up as probands for many med lab assays after passing a questionnaire with answers suggesting their health—at least: the absence of disease (Figure drawn by Wolfgang Hermann, Ph.D.) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Fig. 10.1

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Fig. 10.3

Measured platelet concentrations from the SENIORLABOR study. Please note that regression analysis depicts a slight decrease with advancing age (Figure drawn by Wolfgang Hermann, Ph.D.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Complement system with its cell receptors. The upper part of the figure depicts the entry sites with the protein designation of the classical and alternate pathways. The lower part shows the cell surface receptors for the cognate ligands, which, after binding, will transmit the signal to the cell interior (namely nucleus and mitochondria), instructing the cell what to do . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drugs in development for potential antiaging effect. Many clinical studies in seniors include the neologism “geroprotector” which has been used for a decade. The pharmaceutical industry is bound to retard senescence. There are drugs (for example, metformin) used for chronic diseases which wait for their repurposing to geroprotection . . . . Resveratrols’ simple formula. Resveratrol is a stilbenoid, a natural phenol contained in red wine, and a phytoalexin produced by several plants in response to injury or when the plant is under attack by pathogens such as bacteria or fungi. Sources of resveratrol in food include the skin of grapes, blueberries, raspberries, mulberries, and peanuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Posture takes us away from looking old. This sketch shows an older man sitting at a table, once on the left, upright in perfect posture, well dressed and well groomed, soigné. The same person sitting on the right shows him bent over and slumped over. The same person gives the impression of being older and frailer. The posture of us humans decides our degree of senescence as judged by an observer. Tu ne cede malis (senectute !), sed contra audentior ito (Vergil, Aeneis V > I, 95). (Drawn by www.bilderkram.ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Chapter 1

Time

Cupidus Rerum Novarum Tempus fugit Laetus in praesens animus, quod ultra est, oderit curare Let us be happy in the present and not worry about what will arrive (Horace, Odes II)

1.1 Senescence is Time Dependent We think the mystery (elixir of youth) of senescence is slowly but steadily waning— biochemical and genomic advancements are unstoppable. We, the authors of this book, are convinced that modern insights will not change the world but will contribute to a new view on pursuing the aging parcours of humans. In the almanac of literature on senescence, the forward movement in our biochemical knowledge of the topic accelerates with ever-increasing speed. We are close to understanding senescence, not least because the handling of big data, artificial intelligence, and many new journals available online around the globe can make scribal information obsolete overnight. Many journals edited by potent publishers in print and on the web reach a global audience. We can divide the carrier publications into biochemistry, genomics, and gerontology. Examples are the Journal of Cell Biology, Gerontology, the Journal of Gerontology, and Age&Aging, respectively. Of course, standards with high impact increasingly feature senescence papers. In fact, what urges us to set pen for this book is to dwell on the most daring development we currently perceive: senescence not as forward but as a backward time machine—rejuvenation—a philosophical context in such a daring topic will not prevent us from spelling out our thinking. Of course, we also enjoy writing up this book at the points of contact between mystery and experimentally proven hard facts. Astonishing enough, senescence has not received the attention it deserves from the point of view of science, say 100 years back. Heinrich Heine (1797–1856) asks: “What is a dream? What is death? An interruption of life? Or a complete arrest of life? Yes, for those who know only past and future and ignore the life of every moment of the presence—in between—for © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_1

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these, death must be terrible. They lose the crutches of Space and Time to then sink into the eternal nothing” (Heine 1834). Talking senescence, one needs to be at stake with acuteness of thought about what is meant with the term time, time setting the stage, the timeline of senescence being a dynamic event; senescence may thus evolve fast (quick, prompt, rapid, presto) or slow (tardy, laggard, andante), some adjectives or adverbs built on time perception. Time might be felt by babies already when it is time upon arrival for the next suckling session. Time worth saving, time worth money, and time when wasted put us in a bad mood. The motion picture industry makes actors travel to the past. For some, time flows: is it then away? As the sun rises behind a mountain or when it sets behind the ocean, we realize that this passes by rather fast, sometimes a little slower, depending on the season. In the Gallic War (VI, 12.1), we read: Cum Caesar in Galliam venit (perfect) alteris factiones principes erant (imperfect) (Caesar 1783). As one can see, in Latin, stories are told in perfect (tempus perfectum, i.e., accomplished time). In contrast, in English and Indo-European languages, we designate this as imperfect, which is not imperfect at all. When annoyed, we like to kill time. When painting watercolor on site, we must be fast for appropriate shades and warmth of colors; sorting out this problem is central to good color if painting is to be more than the transposition of color from the paintbox to paper. Time has done its change on the object except perhaps rainy skies helping the painter with illumination gray in gray. Jérôme Lèbre (*1967) scrutinizes the current trend of accelerating events. Toujours plus vite is a general requirement for innovations, mutations, and rhythms— Lèbre asks “why?” In his recent book “Eloge de l’Immobilité” the author opposes rest to movement. Immobility is stressful (jail, hospital, traffic jam) but can also be rewarding (meditation, prayer, writing); it is challenging to assign senescence here (Lèbre 2018). As puts Ennio Morricone (1928–2020) in “La morte della musica”, the flow of time is measured by natural cycles instead of clocks and watches—he, the composer, identifies music pieces as an outstanding means to disturb this flow (Morricone 2016).

1.2 The Eranos Lecture of Monte Verità The Eranos-Jung lectures 2018 of Monte Verità (Ascona, Switzerland) featured the presentation of Roberto Casati (*1961) of the Institut Jean Nicod, CNRS-EHESSENS, Paris, France, on the “Prospectiveness of Time: new techniques and new categories to study time” In his words, Casati refers to the relationship of time perception with thinking, spirit, soul, and mente (spirito, anima, mente). He starts with the current lifestyle; we have no time; we are prisoners of acceleration, of the immediate and instantaneous Roberto Casati. Real time is the time that annulates itself, narrows the richness of thought and our current state, and threatens us from different angles. Carlo Rovelli (*1956), the author of “Seven Brief Lessons on Physics and The Order of Time”, has written as

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last title “The Reality is Not What it Seems”: why do we remember the past and not the future? Do we exist in time? Does time exist in us? He writes: “the incessant happening that wearies the world is not ordered along a timeline, is not measured by a gigantic tick-tocking” (Rovelli 2014). For all intents and purposes, John Steinbeck (1902–1968) might have known this beforehand; his “Travels with Charley” goes through corridor trains of time perception “the actual time on the way from Chicago, IL, was short, but the overwhelming size and variety of the land, the many incidents and people along the way, had stretched time out of all bearing. For it is not true that an uneventful time in the past is remembered as fast. On the contrary, it takes the time-stones of events to give a memory dimension. Eventlessness collapses time” (Steinbeck 1962). This goes along with Alexander von Humboldt (1769–1859) stating, “we had stayed at Tenerife for a few days only, yet we left the island feeling we had lived there for a long time” (Gebauer et al. 2009). Historical and evolutionary time behind us has determined the current human lifespan, from short-lived primate ancestors to contemporary centenarians most frequent in Japan, Sweden, and other longevity frontrunners. In verbal expression, the ground form of verbs is called infinitive, which can be read as forever. This trajectory must be understood and analyzed if we want to understand the biological significance of senescence and the cultural significance of longevity. One may assume that paleoanthropology deals only with the past. The thinking goes that, beyond a curious, somehow romantic interest in the early accounts of our ancestors, there is not much that this discipline can add to the understanding of present-day humans. South Korean palaeoanthropologist Mrs. Sang-Hee Lee (*1966), who investigates our evolving species, disputes that view in “Close Encounters with Humankind”. She shows us humans as a living and still changing outcome of an interplay between biology and natural selection over the roughly 6 million years since hominids diverged from the chimpanzee lineage (Lee and Yoon 2018).

1.3 Senescence on the Move Progress of senescence would start at birth, so say some. Let us call this rather maturation than senescence. The question is, when does the shake separating maturation from senescence tip over? All too often, people reason over life matters based on rough material. As Henri Bergson (1859–1941) in his‚ “L’évolution créatrice” puts forward, even maturity and old age are attributes of my body, independent from a year scale. There is no universal biological law with which individuals can be compared. Each species exhorts its own independence and follows its own capricious cycle by deviating more or less from the timeline. No sweat to consider trees not aging since they are always capable of growing out new branches or cuttings. Such a tree organism, more than being an individual, must be considered a community, with leaves falling, as outlined in Chap. 3 (Bergson 1907).

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Looking at us humans equipped with a brain and memory, Henri Bergson then remarks: “Le fond même de notre existence consciente est mémoire, prolongation du passé dans le présent, durée agissante et irreversible” (our conscious existence is memory and memory is an extension of past into the present—a sand-hour active, irreversible process). And Umberto Eco (1932–2016) lets Venanzio tell to Berengario de Arundel, “se la memoria è un dono di Dio anche la capacità di dimenticare può essere molto buona” (The memory is a gift from the Lord, but forgetfulness can be fulfilling as well) (Eco 1980). Were U. Nydegger’s wife and he not astonished when we invited a friend of us to a concert in a Boston Jazz Club in the late 1970ies by Chuck Mangione (*1940), the entertaining italo-american cornet player, only to find our 30-year-old friend to lean on the backrest in front of him taking a nap! The reader may be familiar with Ben Franklin’s old saying, “Early to bed and early to rise makes a man healthy, wealthy, and wise”. My friend experiences the disorder called advanced sleep-phase disorder (ASPD), not to be confused with antisocial personality disorder, a term which we propose to abate into advanced sleep-phase type (ASPT) or circadian rhythm sleep disorder or advanced sleep-phase syndrome (ASPS) in terminology. Individuals feel very sleepy and go to bed early in the evening (e.g., 6:00–8:00 p.m.) and wake up very early in the morning upon a rise from bed immediately, followed by a very productive period. Indeed, the Japanese conductor Sejij Ozawa (*1935) studies scores very early in the morning and, all by not presuming that his work compares to orchestra conductors’ job, Japanese writer Haruki Murakami (*1949) also works from 4 o’clock a.m. on when he concentrates best. Adolf Portmann (1897–1982), in his book “Biologie und Geist”, describes basic features of chronobiology: the time cycles span different lengths: day/night 24 h or lunar 28 days or seasonal year-round. In man, oscillation is maintained by genetic programs (the names of the genes are: Clock, Bmal1, Chrono, Cry, and Per) completed by melatonin, periodical aerobic glycolysis intensity, and lipid signaling: the impact of these players on well-being and senescence are topic of many studies (Portmann 1956). For the subjective way to play for time or to temporize, we encounter Henry David Thoreau (1817–1862), the “Heidegger (1889–1976) of the United States of America”, who experienced what many of us go through as him, when he writes in Chapter 4 of Walden—the book from Thoreau: “My days were not days of the week, bearing the stamp of any heathen deity, nor were they minced into hours and fretted by the ticking of a clock; for I lived like the Puri Indians, of whom it is said that for yesterday, today, and tomorrow they have only one word, and they express the variety of meaning by pointing thumb backward for yesterday forward for tomorrow, and overhead for the passing day” (Thoreau 1854). With the extension of life expectancy during the last 100 years, an individual has added 200 min to their day course–bluntly spending it watching Television as the French philosopher Michel Serres (1930–2019) not long since used to joke. As with the time course of maturation, the time course of senescence also might follow a stepwise, nonlinear path. The development of newborns brings us from breastfeeding to the bottle, and the step from newborn to toddler is a well-perceived change from the longer periods of newborn and toddler stages. All of a sudden, the child walks,

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and the girls develop mammae in short periods, similar to beard growing in boys on short notice. Pubescent hairs grow “overnight”; at least they appear and come to our attention, not to mention breaking of their voices: puberty and transition to adult life are big steps. How about senescence when it comes visible with wrinkles, calvitia, and loss of energy? Literature perceives them as cumulative and gradual. Only when we meet old friends after a long time, we are amazed how “all of a sudden” they look older to the point where we do not recognize them unless asking them, “what’s your name?” As the other said, seeing a friend after years: “tu a pris un coup de vieux”. Twentieth-century physics shows that the world cannot be thought of as a succession of presents, as demonstrated by Carlo Rovelli. High Lama of Shangri-La tells the intellectual pianist Convey–you will have time–that rare and lovely gift that your Western countries have lost the more they have pursued it. Think for a moment. You will have time to read–never again will you skim pages to save minutes (cited from Hilton 1988). Time elapses while awaiting death: since we ignore the date and time of our death unless we take a risk or plan suicide, the time remaining should nevertheless be measurable. Man likes to measure, to weigh. As Lorraine Daston (*1951) asserts, we need to think of life in terms of probability, and life chance, instead of life fate. Two preconditions are to be considered: The notion of (i) statistical probability, statistical regularity, and a belief in the (ii) homogenous categories of individuals to which the regularities apply. Lorraine Daston, a professor at the Max Plank Institute in Berlin (Germany), builds her way to see the world on mathematics intuitively, and she promotes mathematics to the top of all science chapters. If we fail, we take an insurance rate that depends on mathematical risk calculations, ignoring how much time is left until the final reckoning. This differential perception of time is impressive when one compares time space left until putative death arrives—at senescence’s terminal. The diagnosis of pancreas carcinoma in 2021 still being a death sentence where almost each of the affected individuals passes away in less than a year from diagnosis. This space of time left seems long at first glance, but it passes incredibly fast for most of our fellow cancer victims. Not so with victims of accidents, possibly being happy until the last seconds before losing their life. Horace (65–8 A.C.), in his satire I, lets the merchant, envying a soldier, say to him: Militia est potior. Quid enim? Concurritur; horae momento cita mors venit aut victoria laeta “the task of you soldier is better than mine: you fight, and in the short time of an hour, you either die or you happily win the battle”.

The relativity of the profession in one’s life becomes apparent also in the declaration Albert Einstein (1879–1955) made in 1954 when he wrote about initiating his career over again. He would rather choose to become a plumber or a peddler to seek the independence that these vocations afford—in the wake of course, as we all know today, of his regret of having enabled with his work to develop nuclear weapons. The authors think that a relevant driver of such reasoning seems to be curiosity. Our curiosity, this desire for knowledge, thirst or itch for knowledge, does not value the presently existing to understand it. But instead, our curiosity wants to see.

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Only to have seen it, this is enough (Martin Heidegger, 1889–1976, Sein und Zeit—an appealing title for a book but difficult to understand); the term “future” thus becomes a touch of vulgarity, an ecstatic-horizontal perception indeed. For several decades, the seminars on philosophy at the University of Stanford are frequently attended by digital freaks of Silicon Valley. It all began in 1968 with influential philosopher Hubert Dreyfus (1929–2017); “What Computers Can’t Do”, who analyzed the impact of artificial intelligence on our behavior and time perception. The second in the team is Dagfinn Follesdal (*1932), who came to Stanford with his influential book “Understanding Computers and Cognition”, quite obviously related to Heideggers’ theories. Mark Weiser (1952– 1999), Chief of the Palo Alto Research Center (Xerox Park), was a Heidegger adept during his entire career. The Stanford Philosophical Reading Group partly runs on Heidegger’s writings, a metaphysical appreciation of time and its limitations and finalities that even the most elaborate technology can’t overcome. Senescence as a covered phenomenon? This can be covered in several ways: (i) the phenomenon remains undiscovered and unknown, (ii) the phenomenon is suppressed, buried and (iii) the phenomenon is only a delusion, a bluff. In some cases, we are chasing senescence as a dissimulation. This would be the most disabling form because it could send the individual into depression, suitable only for the pocket banking account of the psychiatrist. Ultimately so, Martin Heideggers’ writings deal a lot with death (Chapter 52. The everyday Being until its End as the Existential Term Death, SEIN UND ZEIT, Max Niemeyer Verlag, Tübingen, Germany, 1977). The explication of the everyday existence until its End, death, is verbalized by us as the We. We die only once but not right now. With this “not right now”, We admit that death will surely occur. Nobody doubts that they will pass some moment; it’s a banality. It’s also a truth, a verity revealing to us the authenticity of something that happens. It is, at the same time, a conviction (Heidegger 1977). Let us see senescence in this light with our book! Well experienced by most of us: at moments, we live through short intervals of so many things which usually take days or months to be lived through: a happy day spent on vacation is over much faster than a dull day during work. Last night U. Nydegger had a dream which took him through half of his career in a few minutes. One day he woke up and suddenly felt like an old man, overnight senescence. The disparity of time perception is illustrated by waiting on a train: ten minutes too early on the station on platform 9 3/4 (Harry Potter, by British author J. K. Rowling *1965) creep by so long until finally the train arrives; oppose this to 10 min in a fascinating movie or during a delicious meal: the 10 min fly away. Are you well prepared for an exam taking place three months from now? An eternity! Insufficiently prepared, lots to learn until term: too short these three months! Time perception is relative. As taught in Harry Potter in the Chamber of Secrets, the muggle-born Justin was in danger for several long minutes, as if a minute could be long or short. Johann Peter Hebel (1760–1826) in his Schatzkästlein (“treasure box”) subsumes in a short story written for hard-working farmers of the upper Rhine valley in the nineteenth century entitled‚ trip to Paris that the hands of the world clock

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(“Weltuhr”) rebound from 1814 to 1789. Napoleon Bonaparte (1769–1821) was forced into exile to Elba, whereupon Louis XVIII was enthroned as a Bourbon king. Hence, French Revolution and Napoleon’s reign ended abruptly. Political drawbacks can turn time back, exempting all individuals involved. The Immortal Jellyfish (see Chap. 4) earns its moniker from an unmatched ability: when confronted with danger, it can revert to the polyp stage of development before maturing back into a full-grown jelly—kind of turning back the clock to cheat the predator.

1.4 In Pursuit of Wisdom—What’s Next Time measurement has made much progress and continues to evolve in precision and providing information. Artificial intelligence links time measurements to places using GPS (global positioning system). Thus, at the Winter Olympics Games 2018 in Pyeongchang (Korea), time was measured by Omega, a Swiss-based company providing state-of-the-art timekeeping. Motion sensors attached to athletes’ garments, boots of skiers, sleds of bobsleigh athletes, and uniforms of ice hockey players track real-time time, the best one can say. Not only do these sensors measure live speed, but one uses them to calculate angles, trajectory, and acceleration on the track as well, allowing the athletes to perceive their own time since the start and their ranking. Space ships are time machines. The only way to do something akin to time travel is to accelerate yourself away from earth, then come back. More time will have passed for those who remained on earth, so in a sense, you will return to the future. Time of flight (TOF) mass spectrometers are used in medical laboratories to denote the differential speed (time of flight) from single components of bacteria, viruses, or cells, which were put in a tiny vacuum chamber and bombarded with pulsed laser beams (matrix-assisted laser desorption/ionization MALDI). Space travel joins laboratory medicine. The Alcubierre drive or Alcubierre warp drive is a speculative idea based on a solution of Einstein’s field equations in general relativity as proposed by Mexican theoretical physicist Miguel Alcubierre (*1964). With this, a spacecraft might achieve faster-than-light travel if a configurable energy–density field is at hand. The resulting distortion enables a warp (clinamen, swerve) drive, for the time being, nothing but science fiction. When Albert Einstein (1879–1955) added the speed of light through empty space as independent of the motion of the light source, the space–time interval became understood as combining distance and time. So we can say time is relative. If I return home from the office, I come back home where I left for a productive or futile working day. It is not easy to imagine what a person like Albert Einstein would account for these new insights. While writing this essay, the passing away of physicist Stephen Hawking (1942–2018) (Hawking and Mlodinow 2010) is breaking news, and with him, the remembrance of black holes. Time has no reference in these domains of the universe, a fact Hawking was not tired to recall each time when asked.

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The warp drive is an impulse that allows travel exceeding light speed using a swerve of space–time. It is Hawking who made U. Nydegger “understand” part of quantum physics when he wrote with Leonhard Mlodinow (*1954), “a particle has neither a definite position nor a definite velocity unless and until those quantities are measured by an observer”.

1.5 Boon and Bane With this chapter, we set the stage to relate the senescence dynamics to time passing by—a comparison that does not need much phantasy but can be expressed on a time scale. Or, to conclude “nec dituius in eo morandum” we need not waste any more time over it says Quintilian (Book VIII, 39). In his writing VII, iX 2–6 entitled Institutio Oratoria, Marcus Fabius Quintilian (35–96), Roman educator and rhetorician from Hispania, writes that single words give rise to error when the same noun applies to several things or persons: the Greeks call this homonymy. Thus, senescence or aging can mean several different things, many of them normal things, to put it right: (i) Attaining old age, (ii) becoming senile, (iii) the condition or process of deterioration with age, (iv) loss of a cell’s capacity to divide and/or grow, (v) becoming rotten, or (vi) becoming a member of Gerousia (a council in Sparta, the Council of Elders). Aging, senescence, and maturation—denominations with slightly different meanings—are perceived individually. Whereas senescence represents endogenously controlled degenerative processes leading to death, aging encompasses a wide array of passive or non-regulated, degenerative steps determined by exogenous factors; gradual deterioration with aging can be considered a fail-safe system with collateral turnover prone to repair. Involution, such as with the thymus, may feign senescence and thymic atrophy, which starts at puberty, arriving in all vertebrates. In 1795, Carl Friedrich Gauss (1777–1855), German mathematician, described the bell-shaped normal distribution curve in a coordinate system, in our context on the ordinate the number of observations and on the abscissa any parameter. With a number sufficiently large, a distribution of observations is obtained, which we call normal, and becomes the meaning of continuous probability because the subsequent observation of, say, tomorrow will most probably fall within the bell, if not even in the slot where the curve is at its maximum. 100 years later, Karl Pearson (1857–1936), British mathematician/biostatistician, coins the term “normal curve” to this bell, but he has some caveats when he formulates the difficulties with this term. These models are called normal curves or normal distributions. They were first called “normal” because the pattern occurred in many different types of common measurements. There are many normal curves. In fact, the shape of a normal curve is entirely determined by specifying its standard deviation‚ many years ago, U. Nydegger called the Laplace-Gaussian curve the normal curve, which name, while it avoids the international question of priority, has the disadvantage of leading people to believe that all other distributions of frequency are in one sense or another “abnormal”. That belief is, of course, not justifiable–how nicely put for the message

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of this book! The term “abnormal” has such a bad touch today that in medicine, we avoid the normal–abnormal antagonism. With medical lab results, doctors tell their patients‚ “your cholesterol is off the reference interval” and “your C-reactive protein is above the cutoff”, mostly meaning that the concentration of cholesterol is above a certain limit set by using the Gaussian distribution curve established with at least 120 healthy blood donors. The conceptual presence of normality in an ethical context is a classic in medicine, the reference value calling for plausibility: normal is what is acceptable/reasonable, what is not deviating, or even what is not disturbing; hence it means healthy but not sick. Galen of Pergamon, in the second century A.C., promoted the humoral four-juices doctrine of Hippocrates: yellow and black gall, blood and slime control health—each parameter normal would then also mean: everything normal, healthy. Claude Bernard (1813–1878) and Francois Broussais (1772–1838) took the positivistic concept of normality into medically attested health. Statistically evidenced normality came into full swing when Zabdiel Boylston (1676–1766) wanted (and succeeded) to prove the efficacy of smallpox vaccination in 1721: during a smallpox outbreak in Boston, he inoculated about 248 people by applying pus from smallpox sore to a small wound on the subjects and opened up a measure considered as eradicating today smallpox, which is quite normal today—it is normal to get vaccinated against smallpox with the rare exceptions perhaps that some people refuse to get vaccinated. Georges Canguilhem (1904–1995) opened up the concept that those are healthy who do not know that they are sick—tempting then, to classify senescence into the category of the sick in this context; the limits between normal and pathological are fluid. Youth, working age and the elderly: on a timeline, chronological age (C.A.) and biological age (B.A.) untie. Beyond adolescence, aging metrics involve estimations of changes in fitness, including prediction models to estimate the number of remaining years left to live. A shift in the population’s age distribution toward older ages, an increase in median age, and average life expectancy are investigated under different perspectives, including the appreciation of the functional status of older populations now completed by measures of biomarkers such as DNA-methylation, protein glycation, frailty tests, and cognitive functioning. A substantial disparity in biomarker levels and health status of aging shows up: the difference between chronological age and biological age in large cohorts under consideration is glaring. Recent progress in anti-aging strategies such as transplantation/retransfusion of stem cells, treatment with drugs such as metformin and rapamycin, and potentially repurposed from their original use call for a better understanding of senescence developing at different life decennia. With senescence, “abnormal” certainly applies to the Werner syndrome, the adult progeria, a rare autosomal recessive disorder that makes premature aging appear early in the life cycle. Measured at the calendar year of the affected individual, Werner Syndrome represents abnormally fast aging. Hutchinson-Gilford progeria extremely rare genetic disease senescence affects patients in childhood. The terms “normality” or “normalization” are surrounded by efforts to define their meaning. Quality control and transformation of raw protein abundance data can now be done with R/Bioconductor packages. Words related to it by Merriam-Webster are

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groove, routine, rut, currence, prevalence, conventionality, harmony, orderliness, and peace. But these terms are already an interpretation of what we usually mean when we say that something is normal. Dictionary.com comes closer: conforming to the standard or the common type, usual; regular; natural. The last adverb is undoubtedly the one we need in medicine because abnormal features endanger survival. The doctor telling his patient that all exams were normal, reassures him, and signals good health. In laboratory medicine, we use the term less frequently and replace it with “this exam is in the Reference Interval (R.I.)”, to mean that R.I.s determined with at least 120 apparently healthy blood donors represent normality. Something is or seems normal when it fits with the majority. This statement is only partially true because large groups which hold them normal may defend awkward goals. Thus, normality means joining the crowd and taking up their customs. This implies that what all women and men are doing is normal and morally acceptable. Statistically seen look at Gaussian distribution (Fig. 1.1) of a population assessed in a high number of individuals and go within the 95% confidence interval: each new observation looked at falling within the interval might be called normal. Bayesian distribution Thomas Bayes (1702–1761) was the first to scrutinize the results of blunt statistics, and as a mathematician and theologian, he introduced the aspect of probability (Fig. 1.2). Comparing the senescence stage in elderly of the same age needs underpinning of Bayesian probability. This must result in the aspect we now call “substantial

Fig. 1.1 With FAMH standards, no less than the results of 120 samples must be plotted on a graph. The ideal distribution appears as a bell-shaped curve of which the middle top maximum depicts a maximal probability that the following sample will display. The exposure variable can be compared in cross-sectional studies; data collection and clinical outcome can be analyzed simultaneously, thus describing characteristics of the sample with other study associations of interest (biostatistics). FAMH (FOEDERATIO ANALYTICORUM MEDICINALIUM HELVETICUM): The medical laboratories of Switzerland

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Fig. 1.2 Swoop of Birds. Bird Observers may recognize the species of birds of prey by the flight path they pursue while nose dipping down to a victim: most species dip down straight down (left part of the figure) while others, exceptions, make a stopover to ascertain whether it’s worth it (right part of the figure). Bayes theorem scrutinizes whether all flight patterns are the same and mathematically argues that exceptions from a p-value < 0.005 may also be normal

evidence” by intermingling in the mathematical formulas suitable to approach this goal. A hypothesis is formulated at the outset of the procedure, which needs to be run through to reach the goal. As if to make the whole process more complicated, there are prior probabilities at stake, and to be understood what these mean—they are then updated by what we call posterior probability in light of new, relevant data (evidence). Bayesian interpretation provides a standard set of procedures and formulae to perform this calculation. At the European Congress of Actuaries 2022, (www.eca2022.org), senescence is being dealt with mortality forecasts in health policy making: deterministic and stochastic approaches can be applied to pharmaceutical research, social security to quantitate longevity, senescence, and mortality risk management performed by insurance companies. If a company wants to ensure its business, the new approach is the captive one: With captives, owners of privately owned enterprises achieve benefits unseen with other planning strategies. Longevity is currently a major topic for insurance companies: should they augment the insurance premium, reduce the insurance benefit—or both? And, with a captive insurance company, business owners reach tailored coverages to the risk profile that can fill gaps in their existing commercial policies. Fortunately, Thomas Bayes scrutinized statistical procedures as early as in the eighteenth century, when the artificial intelligence of computer science was unknown. A Textbook of recent date, LOGIC: Lecture Notes for Philosophy, Mathematics, and Computer Science (Springer Undergraduate Texts in Philosophy, SUPT 2021, written by Andrea Iacona (*1955) University of Torino (Italy) transforms, so to speak, Bayes ideas and caveats to our epoch of computer science (Iacona 2021).

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With the sensor technology for measuring athlete’s speed in races, one now has a technology at disposal that allows monitoring movements of our bodies going as much in detail as appreciating multitasking in the kitchen, executed by fine movements of the legs, arms, hands, and fingers as we need them to prepare a Birchermüesli for breakfast. Such ordinary things in everyday life can be subjected to a critical performance appraisal for healthy individuals or patients. Motor activities during meal preparation were monitored in healthy individuals with a neurological disorder or in elderly people using wearable sensor networks. This can be made with single movements, e.g., filling coffee powder in a mug while simultaneously moving from the cupboard to the kitchen table, i.e., and multitask condition indeed. Motor performance can be quantified by the median frequencies ( f m ) of hand trajectories and wrist accelerations. In a recent study, the probability that multitasking occurred was based on the obtained motor information and estimated using a Naive Bayes Model. The Bayesian probability estimator showed task distinction for the wrist accelerometer data at the high and low-value ranges. The likelihood of encountering a particular motor performance during well-established everyday activities, such as preparing a simple meal, changed when additional (cognitive) tasks were performed. Within a healthy population, the probability of lower acceleration frequency patterns was observed to increase when people were asked to multitask. Cognitive decline due to aging or disease might yield even more significant differences, which can be used for quantitative estimation of senescence. Normal: nothing is normal and everything is normal and the middle between nothing and everything is normal, a pun compatible with Johann Wolfgang von Goethe (1749–1832) in his essay‚ A Word for Young Poets: “Ihr habt jetzt eigentlich keine Norm, und die müsst ihr euch selbst geben” (there is no norm for you therefore you have to set it for yourself) and, from the same author: das Sollen wird dem Menschen auferlegt, das Muss ist eine Harte Nuss, das Wollen legt der Mensch sich selbst auf—des Menschen Wille ist sein Himmelreich (from: “Shakespeare und kein Ende”: “the To-Do is imposed, the Must is a hard nut, the Wish is ones own and the Will is Heaven”). Abnormal is terrible, if not eccentric. When we judge something to be normal, it is usually perceived as OK. Here, Manichaeism may help—a religion based on gnostic dualism founded by the Iranian prophet Mani: Manichaeism taught an elaborate dualistic concept describing the struggle between a good, spiritual world of light, and a material world of darkness which makes that normal and abnormal, i.e., good and evil both are fine. At this point, we need to go back to Martin Heidegger teaching us about curiosity and nosiness. U. Nydegger and Th. Lung and their readers want to see senescence and rejuvenation in this context; what a redemption. Alain de Botton, born (*1969), in his oeuvre Art as Therapy (Phaidon, London 2013) helps Heidegger and us in a way but not entirely: biochemistry and genomics are not typified in art (de Botton and Armstrong 2013). Now in the analysis of understanding and determinedness is for Heidegger, the lumen naturale, the understanding. The word “envision” means many things, we need to see. We need our eyes to visualize senescence and rejuvenation, putative glades of our being. It was Augustinus, in his theological writings, who describes the first as we know the relationship between seeing something and

References

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interpreting it: Ad oculos enim videre proprie pertinet (English: For to see properly belongs to the eyes). When we are born and educated by our parents or in an extra-familial education environment, we learn to cope with life’s circumstances. At a younger age, learning by doing charisma applies. Burning your fingers for the first time on a cooking plate, feeling cold when insufficiently dressed, getting wet without an umbrella, or being punished for misconduct as examples to avoid future mishaps is educational. Silly people repeat the same mistakes over and over again, and intelligent people commit new mistakes, both of them not immune to mistakes. And thoughts then indicate to us that it is not normal to touch a hot plate, it is not normal to go out without sufficient clothing or to walk in the rain without a raincoat, and it is normal to behave gently and, conversely, it is normal to take an umbrella when the rain pours. The normality then becomes a comfort zone—only doing what is normal favors the daily routine living, le train -train quotidien’ and precludes one from opening the eyes to other dimensions. The landmarks we acquired, we avoid leaving them, as we avoid the effort to quit habits acquired with experience, sometimes with pain or bad memories. As Bertrand Piccard (*1958) (https://solarimpulse.com) tells us, before rejecting something abnormal, we would first look into it, evaluate it, and consider that pursuing it could turn to our advantage. Piccard adheres to a fundamental principle: to let go in front of any difficulties, not to try to go against adversity but to follow it in order not to waste energy provided a pinch of look goes along. With his project Solar Impulse Foundation, then as the son of his father Jacques Piccard (1922–2008) already with the bathyscaphe (bathyscaphe is a free-diving deep-sea submersible) down the ocean and his grandfather Auguste Piccard (1884–1962) with his helium balloon rejected the normal—normal here understood as reasonable, i.e., avoiding risk. Letting go makes it possible to distance oneself from a situation and apprehend it by changing the angle of view, an effective tool to be released and more lucid. Beyond the philosophical message, the path of the scientist and ecologist is exciting. His work ends with the principle of “ecohumanity”: beautiful neologism, in which we find the totally humanistic and responsible ecologists we are understanding senescence at its best.

References Bergson H (1907) L’évolution créatrice’ Caesar GI (1783) Commentarii de bello Gallico de Botton A, Armstrong J (2013) Art as Therapy Eco U (1980) Il nome della rosa Gebauer A, von Humboldt A, Ette O, Zech V (2009) Alexander von Huboldt, seine Woche auf Teneriffa 1799, 208p Heidegger M (1977) Sein und Zeit Heine H (1834) Aus den Memoiren des Herren von Schnabelewopski Hilton J (1988) Lost horizon. Simon and Schuster

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Iacona A (2021) LOGIC: lecture notes for philosophy, mathematics, and computer science. 2021 [cited 2022 Oct 2]; Available from: https://doi.org/10.1007/978-3-030-64811-4 Lèbre J (2018) Éloge de L’immobilité, 380p Lee S-H, Yoon S-Y (2018) Close encounters with humankind, 304p Morricone E (2016) Inseguendo quel suono. La mia musica, la mia vita, 481p Portmann A (1956) Biologie und Geist Rovelli C (2014) Sette brevi lezioni di fisica Steinbeck J (1962) Travels with charley: in search of America, 288p Thoreau HD (1854) Walden, 352p

Chapter 2

Genetics—The Language of Proteomics

Cupidus Rerum Novarum Nam cum Academicis incerta luctatio est, qui nihil affirmant et quasi desperata cognitione certi id sequi volunt quodcumque veri simile videatur For there is no coming to grips with the academics, who affirm nothing positively, and despair of knowledge of certain truths, make up their minds to take apparent probability as their guide (Horace, Odes II)

2.1 Manipulate the Back and Forth Meaning with Genomics In 2007, the trickle of insights about genetic risk factors in common diseases turned into a burst, with almost any adverse condition touching us being re-conducted to a genetic background. Clinicians may now use GWAS (genome-wide association studies) to pinpoint defined disease states. But the “one gene—one disease” metaphor does not hold overall and, most deceiving or luckily not deceiving, we cannot (yet?) read senescence on the genome. The authors encounter with Deoxy (Ribo) Nucleic Acid when U. Nydegger saw a patient with autoimmune disease, i.e., Systemic Lupus Erythematosus, who in her blood plasma featured autoantibodies against DNA. In the 1970s, this finding was enigmatic, and DNA was still the content of cell nuclei discovered by Friedrich Miescher (1844–1895) in the Rhein River salmons’ spawn. The decisive revolution came with Francis S. Collins, (*1950) director of the U.S. Genome Research Institute, and his team, attempting to sequence all three billion letters of the code, in his words, reading the language of life. Thanks to fossil and botanical remains and the DNA extracted from them, we know that Neanderthals are still here: together with us in deep time and part of us forever. So writes Giorgio Manzi (*1958), a teacher of anthropology at the Sapienza University in Rome. His recent book starts out with the meaningful words: “I am sitting on a limestone boulder facing the Tyrrhenian sea. Behind me lies the cave of Capo Circeo, frequented by the Neanderthals; a story of a species similar to humans but © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_2

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also profoundly different due to hundreds of millennia of evolutionary separation”. Genetic proximity facilitated crossbreeding, which has left enduring traces in the Homo sapiens. One can now analyze old DNA obtained from the remains of people buried in beakers. The Bell Beaker culture, expression shortened to Beaker culture, 2900–1800 BC, was lived in prehistoric western and central Europe starting in the late neolithic or chalcolithic and running into the early Bronze Age. The term was coined by John Abercrombie (not the guitarist!) based on the culture’s distinctive pottery beakers, initially interpreted to serve as beer-drinking vessels. In Switzerland, a beaker was also found near Bevaix, NE. We need to consider here the Beaker Culture because of these recipients holding perhaps 20 L and with a height of a maximum of one meter, served as burial recipients for deceased dwellers, mostly containing the head, on the finding sites in the form of skull remnants indeed, a source for ancient DNA sampling mostly in the petrous part which contains the ear and is rich in DNA. The Cheddar man is of utmost interest to Britons and still bothers the country, even though it is quietly at rest in a museum coffin. It was discovered 100 years ago in Somerset County, U.K., and alluded to the Middle Stone Age, considered a sensational discovery. It was the oldest ever discovered skeleton with entire conserved bones on the British Islands. Cheddar Man was the first modern Briton and was sitting in a cave 10,000 years before our time. One-tenth of his DNA is still found in modern Englishmen, with the surprise, however, to have had blue eyes and dark skin, so the geneticists are convinced. The retired history teacher Adrian Targett who lives close to the cavity where Cheddar Man was found, remarked a striking similarity to himself “I have even a similar nose”, and the DNA analysis lets us suppose Targett’s mother was a descendant of Cheddar Man (www.lifespan.io). Historical craniometric studies found that the Beaker people looked different than their ancestors in the same geographical area. Genetic studies were done to find European-wide Y-DNA marker frequencies and confirmed as representing an ancient form of DNA indeed. This form of DNA is recovered from samples not preserved specifically for modern analytics of DNA and is recovered from archaeological and historical skeletal material. Mummified tissues and archival collections of non-frozen medical specimens, preserved plant remains, ice and permafrost cores, and Holocene plankton in marine and lake sediments prevent us from drawing solid conclusions. Ancient DNA is of low quality, and preanalytical areas are at stake. More information: David Reich (*1974) (Harvard Medical School 2018) unravels prehistoric genetic code to explore human history. Studies on ancient DNA show the way human populations have split and mixed over time. Neanderthal interbred with the ancestors of non-Africans with north Africans (Green et al. 2010). Thus, DNA can tell us not only about health and disease but also about our past, our identities as people, as families, and as cultures—a kind of new science of looking at the human past. Archeology and linguistics for looking at how people are related to each other can now be done. The work of Reich has documented that the present-day people of Europe are not the same as the people living here 40,000 years ago since the admixture of other people took place upon major migration around 8000 years ago and then another major recreation around 4500 years ago. Reich visits remote places, like the Siberian landscape in the mountains of the Altai, a mountain range in Central and East Asia, where Russia,

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China, Mongolia, and Kazakhstan converge, and where the rivers Irtysh and Ob have their headwaters. With many hundreds of DNA samples from a small region, one can sense differences between closely related material cultures, and one is able to write down mathematical models for how change occurs in time. One can also apply high resolution on how genes that affect complex traits like body height or diabetes risk change over time. It became clear from the Reich data that the mutation for digesting cow’s milk only became common 4000 years ago in Europe and probably came from the east. Reich studies a large number of skeletons from the period and the regions at his disposal. The most dramatic findings are drawn from the Beaker studies. They contend with this extraordinary archaeological culture, the Bell Beaker Complex, that is first documented in western Europe about 4700 years ago and spread into central and northern Europe by 2500 years ago. People were buried in specific configurations— the women buried their heads upwards, the men the other way. The Beaker populations in central Europe were shared by Iberian Beaker samples indistinguishable from the non-Beaker Iberians they lived among. The ancient cultures that have been studied with DNA, such as the Corded Ware and Linearbandkeramik complexes and early European farmers and hunter-gatherers. The people that built Stonehenge, a sophisticated group in Europe with ancient DNA being a new scientific instrument, needs to be put into the hands of archeologists. A comprehensive genomic assessment of the elephantids has revealed that the ancestors of the African forest and savanna elephants of 500,000 years were completely isolated as separate species (Palkopoulou et al. 2018). An international Team around the anthropologist Ron Pinhasi (University of Vienna, Austria) has confirmed Reich’s vision of ancient DNA, revealing insights into migration in the stone and bronze Ages. In other regions, the beaker DNA arrived by migration, most prominently in Great Britain. In 155 samples, one found DNA between 3000 and 6000 years old. At the Botanical Garden in Geneva, Switzerland (see also Chap. 3), the herbarium constitutes one of the jewels of the garden. The herbarium is one of the older ones around and was founded by Augustin-Pyramus de Candolle (1778–1841). With over 400,000 specimens of pressed and dried plants collected since 1794, the herbarium is today conserved in a climate-controlled location and is visited by researchers from the world over. Specimens are separated from sampling plant DNA: millions of small DNA fragments are sequenced in one experiment and then reassociated in order to reconstitute the whole genome of a plant. International Genome Databases of plants currently comprise some 17,000 species and can be sorted by plant kingdom, group, and subgroup. Medawar’s idea sometimes referred to as “mutation accumulation”, proposes that late-acting alleles arising by germline mutations could overturn natural selection even with the mutation-affected key traits like survival and reproduction. Over several generations, then they might accumulate within the genome. In transfusion medicine, it is established that the ABO blood types can change due to the impact of such diseases as leukemia or other conditions which impinge on the genome. Pleiotropic genes having opposite effects on fitness at different ages may become harmful at

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later ages when selection is weak “antagonistic pleiotropy”. As Thomas B. L. Kirkwood delineates, mutation accumulation and antagonistic pleiotropy theories proved the backbone for much of the current thinking about the evolutionary genetics of aging. Senescence here finds its genetic background. In recent years, phenotypic variation at the cellular and organismal levels became known to result from changes to epigenetic and epitranscriptomic landscapes, mediated by a range of modifications to chromatin and RNA. It is now uncontested that dysregulation of chromatin and RNA modifications underlie human diseases and, why not, senescence. It was purported that genetic variants are risking of causing disease. The glitch affected also involved the turning “on” and turning “off” at the right time. DNA is a double-helix and has 2 strands composed of polynucleotides arranged in opposite directions—each chain is a polymer of subunits called nucleotides—hence the name polynucleotide: guanine, and adenine, cytosine, and thymine (Fig. 2.1). Each strand uses a backbone made up of sugar molecules linked together with phosphate. The 3' C of a sugar molecule is connected through a phosphate group to the next sugar. This linkage is also called a 3' –5' phosphodiester linkage. All DNA strands are read from the 5' to the 3' end and terminate in a sugar molecule. Each sugar molecule is covalently linked to one of 4 possible bases, the double-ringed purines adenine and guanine, and the single-ringed pyrimidines cytosine and thymine. DNA is at the center of interest for our topic of senescence, with the incorporation of composite clinical features of phenotypic age that capture differences in lifespan and health span. The CpG sites are regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide made in the linear sequence of bases along its 5' → 3' direction. CpG sites occur with high frequency in genomic regions called CpG islands. The genetic sequence alone does not represent the full picture of gene expression or cellular function. Epigenetic mechanisms, such as methylation of DNA, influence gene activity without changing the DNA sequence. Let us imagine the epigenome with ill-adapted DNA curls termed histones which are specialized proteins. Wisps of hair, i.e., DNA sections which are closely wrapped DNA, are inactive. Those wisps laying a little remote are active and interact with biochemicals in the surrounding milieu—when we age, the curls get loose, and sets of DNA are released. Little but significant parts of DNA are broken: mistakes in the epigenome translate to diseases like cancer, Alzheimer, and cardiovascular problems. Genomic activity, in this example, is a bad property. Cytosines in CpG dinucleotides can be methylated to form 5-methylcytosines. Enzymes that add a methyl group are called DNA methyltransferases. In mammals, 70–80% of CpG cytosines are methylated. Methylating the cytosine within a gene can change its expression, a mechanism that is part of a larger field of science studying gene regulation that is called epigenetics. Methylated cytosines often mutate into thymines. In humans, about 70% of promoters located near the transcription start site of a gene (proximal promoters) contain a CpG island. The Alzheimer’s gene predisposition relates to the gene dubbed with APOE4. In these individuals, the DNA doubles or triples the risk of developing Alzheimer’s, compared with someone without this gene. People with two copies of APOE4 have a risk of developing the disease eight to 12 times as great as those with other versions of APOE.

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Fig. 2.1 DNA ladder with its rungs. The rungs of the DNA ladder consist of pairs of four chemicals, called bases, abbreviated A, C, T, G. Its backbone is a monotonous string of sugars and phosphates. The information content resides in those bases arranged within the interior, where A pairs with T and C always pairs with G. This is the code of life. Science and mystery join when Bill Clinton (*1946) tells Francis Collins (*1950), “we are learning the language in which God created life”. Furthermore, we are learning to manipulate the sequence of DNA components, thus changing the genome. Single-cell genomics is at the doorstep

The study of transcription of genetic information on the nuclear level guided by transcription factors is currently taking shape as a revolutionary tool. Research groups around the world—we here cite one from the Graduate School of Medicine in Kyoto, Japan—address such factors to study the evolution of blood cells from the beginning in sponges up to the human species (Nagahata et al. 2022). By comparing gene expression patterns in phagocytic cells from mice to those from a tunicate (marine invertebrate animal), the transmission factor type CEBP a was identified as an emerger of initial blood cell ancestor of phagocytic cells inheriting a phagocytic program from unicellular organisms (Graf 2022). DNA can now be designed to self-assemble into target shapes, but the size and quantity of objects that can be prepared are limited. As you see in Fig. 2.2, the enzyme helicase splits DNA into two strands such as to allow the copying of the molecule. The polymerase chain reaction (PCR) is a method of making exact copies of genetic sequences. The idea came to Kary Mullis (1944–2019) in 1983 back in

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Fig. 2.2 Helicase induced DNA Split. DNA histones and RNA histones, often associated with polymerases, are enzymes that provide structural support to a chromosome. They do this by unwinding the parental DNA. Helicase may be seen as a motor resisting the base-pairing energy of the DNA. That DNA molecules, even the very long ones, can fit into the cell nucleus, they have to wrap around complexes of histone proteins, giving the chromosome a more compact shape. Some variants of histones are associated with the regulation of gene expression, and many of us believe that this has something to do with senescence, impacting the life clock. The accelerated aging disease Werner syndrome patients showed dysbalanced helicase activity, suggesting histones’ role in senescence. Quae veritati operam dat, incomposita sit et simplex (Seneca, letter 40: The style we have to apply here must be straightforward and simple)!

California when he fantasized about synthesizing genetic fragments, an imagination that brought him the Nobel prize. A pair of primers brackets the sought-for DNA sequence and copies it using DNA polymerase, a technique that allows the amplification of a small stretch of DNA and has now become a standard procedure in molecular biology laboratories. The PCR technique first heats the DNA to break its double-helix structure into two strands. Next, it will cycle to a cooler temperature that allows tailored reagent primers (which one can buy) to bind to specific target sequences within the strands. The samples are then warmed up again, and enzymes would get to work splitting off the primers to finish replicating the complementary DNA sequences. The cycle then is repeated, and ultimately, a lot of copies of the target strands are generated with each cycle. Special fluorescent tags are later added to the sample to flag the presence of those amplified short DNA sequences of interest. Nature makes self-assembly mechanisms to yield definite forms and shapes, from tertiary structure folds of proteins to the formation of lipid bilayers to balanced interactions of Earth’s entire biological systems. Designer nanostructures made from DNA, like biopolymers DNA and RNA, can assemble biomimetic structures able even to communicate with each other, apt to regulate functions. Now that COVID has revealed how important it is for testing in SARS-CoV-2 Corona Virus patient care, portable and slim devices are developed; Alveo Technologies recently designed a handheld PCR molecular testing machine that gives results in 30 min. The engineering company “Solarkiosk Solutions” develops a PCR technique that takes its energy from solar power, a much-welcomed option in Africa, where in certain regions, hookups to the electricity grid are not possible. Recurrence of reactive PCR tests for COVID-19 disease, even in the absence of symptoms, is a now frequent finding: How come? An explanation is found in what geneticists call “reverse-transcription”, a phenomenon that involves the integration of SARS-CoV-2

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RNA into the genome (Zhang et al. 2021). Viral sequences integrate into the DNA of the host cells with the support of viral subgenomic RNA. Such transcription of integrated viral DNA into the DNA of the host cell is responsible for reactive PCR long after the initial infection. These virus-specific sections of PCR-reactive DNA are called Long interspersed nuclear element (LINE) retrotransposons. Hopefully, they do not reactivate and initiate recurrent COVID-19, but we cannot exclude that they are responsible for post-COVID-19 fatigue. A similar mechanism, i.e., LINE, might be seen with the Varicella Zoster Virus, which awakes decades after initial infection with varicella disease when immunosenescence allows the development of herpes zoster disease. Clinicians may be astonished at how fast progress follows the ductus of Dugald Stewart (1753–1828) “The faculty of imagination is the principal source improvement”. Nature just wields her power and uses every particular weakness to make even the strongest conscious of her. Seneca, in his letter from a Stoic XI, cites the blush, i.e., the habit of suddenly reddening the faces of men of even the most dignified demeanor. This is more noticeable in younger individuals with their “hotter” blood and sensitive complexions; nevertheless, seasoned men and aging men alike are affected by it: native DNA and repaired DNA would react the same. As we get older, we lose our capacity to repair DNA—senescence at its best. DNA repair is essential for cell vitality, cell survival, and cancer prevention, yet cells’ ability to patch up damaged DNA declines with age for reasons not fully understood. With the CRISPR Cas technology, it became imaginable to impact DNA well-being on its repair. Evidently, this technology must adhere to strict ethical rules: editing genomes is a seducing possibility and subject to spectacular headlines which sooner or later prove full of gaps—a researcher recently shocked the world by “creating” babies with edited genomes. A difficulty in this will be to ensure that any new rules must be adhered to without deterring solid science. Researchers led by scientists at Harvard Medical School reveal a critical step in a molecular chain of events that allows cells to mend their broken DNA. Chromosome breakage in blood or fibroblasts or germline mutation analysis is now med lab analyses, which can be used to diagnose hereditary diseases, mostly autosomal. This is the view also supported by the molecular biologist from Rome (Italy); Isabella Saggio (La Sapienza) (Saggio 2022). The findings offer critical insight into how and why the body’s ability to fix DNA dwindles over time and point to a previously unknown role for the signaling molecule nicotinamide adenine dinucleotide (NAD) as a key regulator of protein-toprotein interactions in DNA repair. NAD was identified early in the last century and is already known for its role as a controller of cell-damaging oxidation. NAD precursor nicotine amide impacts obesity-associated mitochondrial dysfunction and metabolic syndrome. David Sinclair, Australian biologist (*1969) of the Paul F. Glenn Center for Biology of Aging Research at Harvard Medical School, found out that the protein which repairs DNA, PARP2, begins to be impaired as we get older. This is done by another protein that sticks to PARP2: this protein, dubbed DBC1, stops PARP2 from working. The researchers fed old mice a molecule termed NMN then the mice turned in NAD. NAD fed to mice pops the PARP2-DBC1 complex apart PARP2, which then

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becomes as active in DNA repair as it does its job in a young mouse: the capacity of DNA of the old mouse goes back to that of the young lab animal. In this circuitry, proteins are important players. The best-understood genes are those that code for a protein. This process involves first making an RNA copy of the DNA; that RNA is then transported to the ribosomes, which are our protein factories. We have learned in the last 20 years that proteins not only are the result and product of genetically coded amino acid sequences, assembled and folded, but no, proteins create their own world, enzymes certainly being part of it (Fig. 2.3). Aromatic residues cluster in the core of folded proteins, and aromatic side chains undergo ring flips—that is, 180° rotations; it was suggested that by his, shaking motions would impact on surrounding protein environment. The structural details might impact senescence. Using Nuclear Magnetic Resonance (NMR), flipping tyrosine side chains were identified in proteome-wide sequence analysis, and thus, local proteome environment may impact aging (Mariño Pérez et al. 2022). How long we live is determined by a range of factors, including our lifestyle and how well we handle biological elements from midlife. However, genetics and how long our parental relatives lived also play a role. Now, the number of genes we know influence lifespan has expanded, potentially paving the way to new therapeutic targets to prolong life. The study this revealing, funded by the Medical Research Council in Great Britain and conducted in collaboration with a number of U.S. universities, undertook a genome-wide search for variants influencing how long participants’ parents lived. The team studied 389,166 volunteers who took part in the U.K. Biobank, with confirmation in the U.S. Health and Retirement Study and the Wisconsin Longitudinal Study. The DNA samples from the volunteers carry the genetics of their biological parents, so providing a practical way of studying exceptionally long lifespans. Eight genetic variants had already been linked to lifespan, mainly involved in heart disease and dementia. The latest study has expanded this

Fig. 2.3 Genomics as the backbone of Proteomics. The structure and function of proteins are programmed in detail by DNA sequences. This graph roughly depicts the relationship between genomics and proteomics. Each protein analysis depends on 100% from DNA programming with RNA to the ribosomal assembly of selected amino acids

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to 25 genes in all, with some specific to mothers’ or fathers’ lifespans separately. Dr. Luke Pilling, who undertook the analyses, said: “We have identified new pathways that contribute to survival, as well as confirming others. These targets, including inflammatory and cardiovascular pathways, offer potentially modifiable targets to reduce the risk of an earlier death and improve health”. Drugs targeting senescence have already been shown to extend life in lab animals (see Chap. 10). Genes related to inflammation and autoimmunity-related genes were also prominent, opening up the possibility that precision anti-inflammatory treatments may be helpful in extending life. The results confirm that many genetic variants combine to influence human lifespan: no single gene variant was found to be responsible. The study found evidence to suggest that the genetic variants for average lifespan also influence exceptionally long life expectancy. A genetic risk score combining the top ten variants was statistically associated with parents being centenarians (Pilling et al. 2017). The life extension depends, at least in part, on avoiding cancer. Individuals suspected of having cancer undergo imaging and biopsy—samples of the tumor are excised and examined under the microscope, an exam which takes days, if not weeks, until the result becomes known. Recently, an analysis now called a metaphor “liquid biopsy” to find signs of cancer in a blood sample is increasingly used and tested for its efficacy: a dozen of companies are developing their own technologies, and markets for such tests are in view. The technique comes in on circulating-tumor DNA (ctDNA), a subset of DNA that finds its way into the circulating blood. Amplification and sequencing of such DNA are readily available. GRAIL, a company spun off from Illumina, plans clinical trials, and ctDNA could acquire the status of a biomarker. DNA technology is also on the doorstep when it comes to vaccine development. Genetic vaccines take the form of DNA or RNA that encodes desired proteins—on injection. The genes enter cells which then churn out the immunogenic proteins—an internalized vaccine antigen, so to say. Deborah Nickerson (1954–2021), the human genomics researcher who helped discover genes responsible for cardiovascular disease and autism, employed the findings of the human genome project to sequence the genes of thousands of healthy people revealing how genetic variation could be used to target specific genes that cause inherited disorders. Dr. Nickerson used technologies that made DNA sequencing less expensive; using them, she created a catalog of human genetic variation from a diverse population by sequencing the genes of more than 6500 volunteers. She then made it available online to other researchers, who have advanced it further. It has always stunned U. Nydegger that the DNA of animals, even the ones of plants, is not so much different from the DNA of us humans. Humans have about 20,000 genes on their 23 pairs of chromosomes. The human genome project directed by the U.S. Human Genome Research Institute has unraveled a great number of gene linkages to particular diseases. Healthy DNA has been called by one of the great names in the field, Francis S. Collins (*1950), “The language of life” for its formation and for its maintenance, the organism reads the instructions on what to do on its genome. Collins describes in his book the case of Meg Casey, a woman afflicted with a disorder of accelerated aging, i.e., progeria,

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sometimes termed Hutchinson-Gilford progeria syndrome (HGPS), a rare disease. In progeria patients, the protein lamin is affected by a single mutated letter in the DNA code, a T that should read as a C, located in the middle of a gene that codes the protein lamin A (Collins 2010). If one scans, in the year 2017, a compiled list of the most studied genes—sort of “top hits” of the human genome, and several other genomes besides, one lands on TP53, a hit explained by its tumor suppressor monitor and widely known as a guardian of the genome: it is mutated in about half of all human cancer—no gene is more important. In 40,000 research papers, the following gene assignments make it to the top ten: TP53, TNF, EGFR, VEGFA, APOE, IL6, TGFB1, and MTHFR. This is astonishing because we have 20,000 genes, and it means how much we do not know about because we just don’t bother to research it, says Helen Anne Curry, a young science historian at the University of Cambridge, U.K. As a hematologist, and when U. Nydegger was doing active projects in the mid-1980s, much genetic research made progress in studying hemoglobin, the oxygen-carrying molecule found in red blood cells. More than 10% of all studies on human genetics before 1985 were about hemoglobin in some way. Telomeres are protective beginnings and ends that cap the chromosomes. Loss of structural integrity and accelerated telomer shortening are both associated with biological aging and increased disease risk. Epigenetic factors, including DNA methylation, are important for telomere maintenance.

2.2 Gene Scissor Technology—CRISPR The ease of using gene scissors sparks euphoria but is also a great concern. The DNA sequences of bacterial genes have been found to be regularly interrupted by short sequences of viral DNA: researchers were thus brought to the idea that the chromosomes are doing this to maintain an immunological memory of what happened. Thanks to the incorporation of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) in their sequences, the bacteria immediately identify the predator. The two researchers Emmanuelle Charpentier (*1968) and Jennifer Doudna (*1964) came about the idea of using CRISPR assembled in such a way that it can identify a gene that we want to address. Now, the molecular scissor Cas9 is engaged, cutting DNA. At this stage, one can replace the gene with a substitute of desire, similarly as we insert a new text passage in a document, or one allows the reaction to proceed, whereupon the cell repairs the cut itself, which is prone to errors. With CRISPR, you thus replace a gene or switch off a gene. Compared to older gene technology, CRISPR is faster, cheaper, and more simple to perform: months of work are now replaced by a few days of endeavor. Gene technology meets mass production standards. At the time of this writing, not only rare diseases (i.e., Horton disease) but also more frequent disorders, such as hypertrophic cardiomyopathy, can be prevented, as was recently shown by Shoukhrat Mitalipov (*1961) of the Oregon Healthy and Science

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University in Portland, OR, USA. They used the sperm of men carrying the MYBPC3 gene as well as healthy egg cells: upon such measure, 72% of 58 genetically modified embryos were devoid of the pathological mutation (German et al. 2019). Genomics and proteomics are transitive sciences, i.e., we look at it from the lab bench, and we come to admire the intelligence/innovation of nature. Allopatric speciation, this evolutionary development of a new species upon territorial separation, can reduce gene flow when a geographical barrier separates identical species, thereby promoting genetic divergence. Some people reversed this view and used novel techniques to store data we humans produced—like a computer “where U. Nydegger can store, register, download and save data”. Thus, the nanotechnologist Ned Seeman (1945–2021) built the first self-assembling DNA structures. His group reported the apparently successful building of 2D DNA arrays creating DNA tiles that self-assemble into a connected mosaic following an algorithm, thereby conducting computation (Winfree et al. 1998). DNA nanotechnology might someday complete the electromechanical computation. Several companies are at this time investing a lot of energy in gene-based (therapeutical, life-changing) interventions. Gene expression profiling (GEP) and DNA methylation analyses will render the diagnosis of the senescence stage even more precise—key genes included. As an example, let us cite Sangamo Therapeutics, Inc., which is committed to transforming the lives of patients suffering from serious genetic diseases. In monogenic diseases, an essential protein is not assembled properly or in insufficient quantities as a result of a mutation mainly. Gene therapy means delivering a new copy to replace a defective gene.

References Collins FS (2010) The language of life: DNA and the revolution in personalized medicine, 368p German DM, Mitalipov S, Mishra A, Kaul S (2019) Therapeutic genome editing in cardiovascular diseases. JACC Basic to Transl Sci 4(1):122–131 Graf T (2022) When and how did the first blood cells evolve? Blood, J Am Soc Hematol 140(24):2531–2532 Green RE, Krause J, Briggs AW, Maricic T, Stenzel U, Kircher M et al (2010) A draft sequence of the Neandertal genome. Science (80- ) 328(5979):710–722 Mariño Pérez L, Ielasi FS, Bessa LM, Maurin D, Kragelj J, Blackledge M et al (2022) Visualizing protein breathing motions associated with aromatic ring flipping. Nature 602(7898):695–700 Nagahata Y, Masuda K, Nishimura Y, Ikawa T, Kawaoka S, Kitawaki T et al (2022) Tracing the evolutionary history of blood cells to the unicellular ancestor of animals. Blood, J Am Soc Hematol 140(24):2611–2625 Palkopoulou E, Lipson M, Mallick S, Nielsen S, Rohland N, Baleka S et al (2018) A comprehensive genomic history of extinct and living elephants. Proc Natl Acad Sci USA 115(11):E2566–E2574 Pilling LC, Kuo CL, Sicinski K, Tamosauskaite J, Kuchel GA, Harries W et al (2017) Human longevity: 25 genetic loci associated in 389,166 UK biobank participants. Aging (albany NY). 9(12):2504–2520 Saggio I (2022) L’ età, se esiste. Saremo tutti immortali? 144p

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Winfree E, Liu F, Wenzler LA, Seeman NC (1998) Design and self-assembly of 2D DNA crystals.pdf. Nature. 394:539–544 Zhang L, Richards A, Inmaculada Barrasa M, Hughes SH, Young RA, Jaenisch R (2021) Reversetranscribed SARS-CoV-2 RNA can integrate into the genome of cultured human cells and can be expressed in patient-derived tissues. Proc Natl Acad Sci USA 118(21)

Chapter 3

Senescence in Plants

Cupidus Rerum Novarum Sed neque quam multae species, et nomina quae sint, est numerus The number of species is large, and we can (not) name each one Virgil, Georgica, Song II

3.1 Plants, Good Examples for Senescence Information It is the concern of most of us when deliberating on human life to start out with plant life. We know that the naturalist Albrecht von Haller (1708–1777), father of modern physiology and mentor of the Albrecht-von-Haller-Institut at the Georg-AugustUniversity of Göttingen, Germany, threw a bridge from botany to medicine; von Humboldt passed 1789–1790 in Göttingen, so he was entrenched with the wonders of nature opening the world of science to him. This chapter takes botany as carpet and coulisse on which the science of senescence unfolds, including the “back and forth” opposite locution. Experts visiting the World Economic Forum in Davos, Switzerland, 2018, discussed plant genetics as an artificial intelligence tool accessible to farmers and agriculture. It is the incitement of most of us when trying to understand human life to start out with the exploration of plant life. When Pythagoras visited India, he attended the school of the gymnosophists, i.e., Indian philosophers who pursued asceticism and taught humans the language of animals and plants. On a promenade along a coastal field close to the ocean, he would hear someone saying, “how unhappy am I to be born as a plant” and later on the coast, he found an oyster who said: “O nature! The plant, your creation, must be so happy: when it is cut it regrows, the plant is immortal” (Voltaire—Aventure Indienne, Editions Gallimard 1979, Paris). Many members of the plant kingdom are able to repair. A capacity later in this book examined closely to slow down senescence. Melatonin, our central zeitgeber, along with cortisol, was detected in plants in 1995, and it regulates plant growth and stress response. Abiotic stress, such as cold, heat, and drought, are genetically controlled, and it has been shown that the presence of melatonin can delay leaf senescence (Zheng et al. 2017). As if Chimonanthus © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_3

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Fig. 3.1 Chimonanthus praecox (Wintersweet). One may assume that wintersweet tries to forestall senescence by blooming early on (Photo made by U. Nydegger)

praecox (wintersweet) would want to escape or at least hinder senescence—it was flowering at its best when we visited the Botanical Garden of Geneva on 5th January 2018 (Fig. 3.1). Luc Ferry (*1951) published in 1992 his “Le nouvel ordre écologique—l’arbre, l’animal et l’homme” making him the winner of the Jean-Jacques Rousseau award. In his utopic, archaic, and speculative treatise, Ferry makes life and its creation impinge on the well-being of the blue planet, including the provocation of climatic change. Indeed, the sunlight is absorbed by the photoautotrophic organisms by the one and only pigment chlorophyll—a ringed porphyrin structure with one magnesium in the center. Double bonds allow chlorophyll to exchange electrons quite easily— porphyrins being the most stable chemicals also found in mineral oil and carbon, materials as much as 400 million years old, which is why we call them biogenous in origin. The photosynthesis of plants follows the following simple formula: nCO2 + nH2 O + Light = C6 H12 O6 + nO2 when assigning n = 6, one designates glucose (C6 H12 O6 ) as a final product of photosynthesis. Back one billion years, plants had made an impressive change in the environment of Earth. Chlorophyll, as a producer of oxygen, is so much older than hemoglobin yet parent in chemical structure. Close to 600 million years ago, the up-to-then monopolizing grip of algae was unleashed, and new lifeforms emerged during the Cambrian Explosion. Survival lengths of the organisms then living have been studied

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mainly on plants, and experts assume that a tree living back in the Perm had a survival time as long as a tree of today. The Paleozoic (Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian) goes from 542,000,000 to 252,000,000 years back. The Mesozoic (Triassic, Jurassic, Cretaceous) 252,000,000–66,000,000, and the Cenozoic (Paleogene period, Neogene, Quaternary) goes from then on until today. The larger part of Earth’s history can be studied by sequences of rock formation–only later, from the Cretaceous (Chalk) onwards, with fossil plant information on early life forms emerging. Certain Foraminifera (Protozoa) have not changed their form since the Silurian Period (443–416 million years ago). The lingulae of today are identical to the lingulae from the Paleozoic era, an observation thoroughly treated in the context of time passing in the classic by Henri Bergson (1859–1941, L’évolution créatrice). It is anybody’s best guess that an organism then living went through the same process of senescence as at present. This olive tree from Sardegna reaches 700 years and is an escaper, having passed a long period of senescence (Fig. 3.2). Most plants use canny means, combinations, and traps, and they are under mechanical, ballistic trajectories. The most important process helping the plant to keep genetic information during its differentiation is that differentiated plants can come back to embryonal stages. This enables the plant to regenerate because its totipotent cells can revert. In fact, separated begonia leaves develop roots close to the separation point: adventive sprouts which arise from a single, embryonic-formed epithelial cell. In a treatise termed “autonomous determination”, several mechanisms get Fig. 3.2 Old Olive Tree. About 700-year old Olive tree in Cuglieri (Sardegna, Italy) (Photo with Copyright of WPW)

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involved in autonomous growth stimuli: (i) neighboring cells, (ii) hormones, and (iii) gall-formation (organoid or histoid variety). A mysterious property of plants is their capacity to move. The best-understood movement is due to turgor and chemotropism, which gives a plant the option to explore its environment with tentacles. Thigmotropism is movement upon friction. Autonomous movements, such as response to wind, further add to the wondrous movement of the winding of bean plants around a stick (leftwards, rightwards). A sunflower turning its head toward the sun by twisting its stalk is another example. The way senescence affects these properties is essentially unknown. Trees can get very old: poplar and elms subsist to 600 years, oaks can get 1000 years old, and yew up to 3000 years. If the experimenter prevents the sugar beet from blooming, the plant will live many years. Focus has recently been laid on the swampy floodplains of South Carolina’s Black River: after centuries of shipbuilding with timber, there aren’t very many old trees left except such exemplars as the Angel Oak outside of Charleston. Many bald cypresses (Taxodium distichum) were over 1000 years old when in the year 1492, Christophorus Columbus discovered the Americas. These trees are an example of how the environment might break senescence: the trees have been spared from loggers’ saws, and such ecosystems are important sources of information on climate change. The impact of climate change now becomes visible from space. Global warming strikes the eye of those who look at this European mountain range spanning from the Mediterranean Sea to the Caucasus. Above the tree line, the vegetation shows up in green at locations formerly covered by snow and glaciers (Rumpf et al. 2022). The Swiss Plant Science Web is a group of about 130 botanists (www.swissplantscienceweb.unibas.ch), and many of them look at population genomics, including conservation biology, epigenetics, and else. Nevertheless, these research projects reveal that the arboreal behemoth is said to be up to 1400 years old; plants belong to the oldest east of the Mississippi River growing, still growing, at least the leaves every season, on John’s Island in South Carolina, USA. Angel Oak is 66.5 feet tall, and 22.5 feet around, and it provides an extraordinary 17,200 square feet of shade (Woo et al. 2013). Plant leaves (Fig. 3.3) obey a reproducible life history and are readily accessible for experimental assays.

Fig. 3.3 Leaf Senescence. Once summer is over, chlorophyll (C55 H72 O5 N4 Mg) loses magnesium and changes the light absorption spectrum going from green to yellow (or red). The foliage season in New England, USA, is marvelous to the observer

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Godparent to the science of genetics is those studies on beans conducted in a monastery by Gregor Mendel (1822–1884). Crossing experiments of white and red flowering beans in Brno, now in the Czech Republic, by then part of the AustroHungarian Empire, province of Moravia, were meticulously designed long before James Watson (*1928) and Francis Crick (1916–2004) unveiled DNA as the language of life in the form of brick stones for chromosomes and genes. When Mendel entered the Augustinian Abbey, he took charge of a fine garden outside the refectory founded in 1830 and where plants rarely found in Moravia grew and where he could quietly prick seedlings, probably even before the day was aired. His thoughts were all on birth, growth, and fertility. A herbarium collection was made under the guidance of his Abbot Napp, and Mendel could continue his natural studies, and education in botany, finding ideal conditions there. Today researchers, successors of Mendel, like to use the winter annual with a relatively short life cycle, Arabidopsis thaliana (A. thaliana), as a model plant. The unimposing plant has become a popular model organism in plant biology and genetics. For the complex multicellular eukaryote it is, A. thaliana has a relatively small genome of approximately 135 megabase pairs. It was the first plant to have its genome sequenced and is a convenient tool for understanding the molecular biology of many traits, including flower development and light sensing. Why not the development of senescence? What a similarity between the noun cytokine so much in the limelight in human medicine and the noun cytokinin. This one is designating important control proteins in the processes that contribute to plant senescence. Cytokinins are key regulators of a large number of processes in plant development, like auxins and gibberellins, hormones taking the place of a nerve system though absent in plants. Ballastines and metabolic waste products left over are senescence accelerators—a fact we will have to come back to. Many phytohormones are synthesized in the apical root meristem and transported through the plant in the xylem sap. Cytokinins are involved in several physiological processes, such as promoting cell division and chloroplast maturation, regulating cell growth and differentiation, and monitoring nutrient uptake and senescence. Together with auxin, they also regulate the cell cycle and tissue morphogenesis. Leaves are convenient models in studying senescence: falling in autumn, they conclude their life cycle with a terminal senescent phase, but they certainly do not reflect the senescence of the tree. The Bonsai knows the seasons and changes his leaf dress accordingly (Fig. 3.4). Botanists distinguish sequential senescence, the older leaves falling first from synchronous leave senescence: all leaves fall at the same time. A philosophical aspect might suggest that the falling of leaves allows for the maintenance of juvenescence of the carrier tree allowing blossom in springtime the next year (www.arboretum. harvard.edu). Not only do they change color in fall, but also do they form wrinkles. Wrinkle formation due to age or stretched skin is seen as a nuisance to be avoided, often at financial expense, rather than as a natural testimony of aging. Plums or apples wrinkle as they become old and dehydrate, and Earth’s crust wrinkles in response to plate tectonics. When the fruit ages, water is lost from the interior, and the fruit volume reduces, leaving too much skin on the outside.

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Fig. 3.4 Bonsai—a Maple, still young, about 20 years. Separated from its natural environment, cultivated in our garden in a suburb of Bern, Switzerland, follows seasonal changes (taken here in march 2022, left and may, right). The Asian cultures have known Bonsai cultures for over 1000 years. The idea of growing a Bonsai is to create a miniaturized but realistic representation of nature in the form of a tree. The seasonal foliage of the parent tree is maintained. Bonsais are genetically identical to their grown-up version; Bonsais are non-dwarfed plants—any tree species can be used to grow one (Photo WPW)

The lifespan of leaves transgresses through a series of developmental, physiological, and metabolic stages subject to senescence and death. Magnanimous leave senescence allows redistribution to developing seeds or other parts of the plant and thus is a strategy that has evolved to maximize the fitness of the plant. During the past decade, there has been significant progress toward understanding the key molecular principles of leave senescence thanks to genetic and molecular studies providing models on how to assess senescence in man: contenders being chlorophyll metabolism, levels of chromatin and transcription under the influence of post-transcriptional, translational and post-translational regulation. This is quite different from wood. Wood is an inhomogeneous material—not only do its properties differ in different parts of the microstructure, but there is also considerable variation within a stem and among stems. Lignin, this organic polymer, and cellulose ((C6 H10 O5 )n ) helping the wood remain stiff and strong. Differences in properties within a stem constitute the most important variation factor of wood, often being greater than variation among trees (Wohlleben 2015). Within-tree variation is made up of three main components: intra-ring variations, ring densities, variations in the radial direction through different annual rings, and variations in the longitudinal direction. A tree ring-dating system helps to understand the growth of trees. The widths of tree rings can be measured, and according to meteorological conditions, samples of wood are dated by cross-referencing using databases of ring width reference systems. Some use technical terminology for this

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procedure, i.e., dendrochronology, to mean that time decisively governs growth— will it also make the senescence of the tree visible? Trees have a life cycle that keeps their enigma/secret because tree life spans exceed the spans of human life. Special drills penetrating the bark toward the central axis produce cuts that allow us to estimate a tree’s age. Pinewood is relatively soft and easily processed, offering high strength and elasticity. The best technical properties are found in wood from trees felled at age 80–120 years with well-covered knots. Extensions of pine wood vary in the axial and radial directions. The mechanical robustness depends on quality properties in the radial direction from the core to the perimeter. Thus, compression strength might be increased by 45%, bending strength by 55%, and the modulus of elasticity improved by 99%. The axial and radial variation in the tested properties is explained primarily by the occurrence and proportional contribution of zones of young and mature but not aged wood. These observations make the possibility of obtaining specific types of wood become dependent on the age of the trees designated for felling. It can be expected that the older the trees and the larger their breast-height diameters, the greater will be the quantity of more valuable wood. It should also be borne in mind, however, that in better and stronger habitats for trees, the period of production is generally shorter. This is chiefly related to the trees’ attaining what is called technical maturity. This is determined by many factors affecting the tree aging process, which is regulated chemically. When a tree’s age exceeds approximately 120 years, there is a noticeable drop in the cellulose content, and decomposition of lignin occurs. Aging is also accompanied by changes in the color of the wood tissue: the heartwood becomes redder and the sapwood more yellow. According to Katalin Kránitz in her doctoral thesis, aging does not cause any other changes in the wood structure apart from those mentioned above, but changes occur in the hygroscopic properties of the wood, as well as slight differences in its physical and mechanical properties (Kránitz 2014). Is it thus important that violin makers use wood immersed 12 months into the water before they work on it making the instrument? Such differences became important in musical instrument making. We may go back to the sixteenth century when the Cremona (Italy) school of violin makers around the Amati (family 1538–1740) routinely used spruce as a cover on a maple case for the instrument (Fig. 3.5). Dendrochronological analyses might produce conflicting conclusions when their results are used to determine the year a violin was made. The drums of the late Charlie Watts (1941–2021) also used different woods to enhance the beat of the Rolling Stones. At the department for Forest Ecology, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, at ETH Zurich, climate change is addressed as an indicator for senescence and mortality, the latter being a key process shaping forest dynamics. Thus, there is a growing need for indicators of the likelihood of tree death. During the last decades, an increasing number of tree ring-based studies have aimed to derive growth-mortality functions, mostly using logistic models. No highlight for any universal trade-off between early growth and tree longevity within a species can be seen; the intersite and interspecific variability in growth patterns

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Fig. 3.5 Spruce and maple wood join together to build a Rémy violin. The ribs and back are maples, and the bout is pine. The best woods, especially for the plates, have been seasoned for many years in large wedges, and the seasoning process continues indefinitely after the violin has been made (Photo by U. Nydegger)

before mortality provides valuable information on the nature of the mortality process, which is consistent physiological mechanisms leading to mortality (Cailleret et al. 2017). Sundials, still in use in some countries, are old fashioned although their dictums maintain some philosophical value, e.g., “Amyddst ye flowres, I tell ye houres!” or as a British Essayist put it: “Horas non numero nisi serenas”. The pendula, the sand glass, the clepsydra, and the wristwatch give us abstract means of time, without form, without a face. They are “anemic” instruments of our rooms while the sundial reflects running shadows and the wonders of the world (Maeterlinck 1946). It is Emanuele Coccia (*1976) who draws plant life close to animal life: As yet thanks to plant life our world can exist, providing O2 needed for animal life on Earth. Coming back to a root-and-branch life on Earth: the plant. (original text translated by the author: “Pourtant, c’est grâce aux plantes que notre monde existe, fournisseurs d’ oxygène qui rend possible la vie animale sur terre. Retour sur une forme radicale d’être au monde: la plante”. Stefano Mancuso (*1965), University of Florence, Italy, is in the process of studying a neurological system, possibly at work in plants (Mancuso 2015). The International Society for Plant Signaling & Behavior, of which Mancuso is a founding member, has made senescence and stem cells of plants a topic of the investigations they sponsor (www.psb2017.com) (www. plantbehavior.org). The aim of the present essay was to determine how processes of tree aging affect the properties of wood tissue as described by the basic density and the modulus of elasticity.

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References Cailleret M, Jansen S, Robert EMR, Desoto L, Aakala T, Antos JA et al (2017) A synthesis of radial growth patterns preceding tree mortality. Glob Chang Biol 23(4):1675–1690 Kránitz K (2014) Effect of natural aging on wood. ETH Zurich Maeterlinck M (1946) L’Intelligence des Fleurs Mancuso S (2015) Die Intelligenz der Pflanzen, 188p Rumpf SB, Gravey M, Brönnimann O, Luoto M, Cianfrani C, Mariethoz G et al (2022) From white to green: snow cover loss and increased vegetation productivity in the European Alps. Science (80- ) [Internet] 376(6597):1119–22. Available from: https://www.science.org/doi/abs/10.1126/ science.abn6697 Wohlleben P (2015) The hidden life of trees Woo HR, Kim HJ, Nam HG, Lim PO (2013) Plant leaf senescence and death—regulation by multiple layers of control and implications for aging in general. J Cell Sci 126(21):4823–4833 Zheng X, Tan DX, Allan AC, Zuo B, Zhao Y, Reiter RJ et al (2017) Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress. Sci Rep 7(January 2016):1–12

Chapter 4

Senescence in Animals

Cupidus Rerum Novarum Denique cur acris violentia triste leonum seminium sequitur dolus vulpibus et fuga cervis. A patribus datur, et patrius pavor incitat artus; si non certa sua quia semine seminioque. Vis animi partier crescit cum corpore toto? Why is the aggressiveness of lions inherited from parents to children? The astuteness of wolves, the escape of deers from their fathers; a panic of heredity gives a jerk to their members a reason why each species has its particular soul growing (and senescing?) with its entire body Lucrece, Song III

4.1 Zoological Senescence The animal kingdom throws a bridge from plants to humans and allows us to distinguish lifespan from health span. An enormous variety of animals now inhabits the earth, and many other kinds have lived and died out during the past geological time. Animals differ from one species to another in size, structure, and manner of life, which senescence research has always crossed. On an organizational level, the “steady state” is far from being “steady” at first sight and meant to be a single, static condition; the steady state must be seen as the dynamic equilibrium of many systems that change in successive stages of development. Furthermore, a steady state is here at various levels. There is a steady state at the cellular level by which individual cells are maintained in equilibrium with their environment. There is regulation at the tissue level, at the organ level, and finally at the level of the whole organism. We always looked at animals to study longevity. When Arthur Mangin (1824– 1887) wrote his classic “L’Homme et la Bête” he was fascinated by the then fashionable opinion that animals exist to serve their organs—hence we humans would, in fact, be animals. Carl Linnaeus (1707–1778), the Swedish taxonomist, did not separate the anthropoid apes from humans:—orang, chimpanzee, gibbon, and gorillas unknown to him made it easier to classify the remainder of the apes as humans. Our

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Fig. 4.1 Caenorhabditis elegans, a small nematode. The pioneer in long life—extension of senescence at its best provides a tool in the research lab. The authors remember the burst of research articles starting around 1980 when the genetics of this free-living worm became known, largely confirmed with ever-more precise genomic techniques. One can now override senescence in these animals to extend their survival by a factor of two. Caenorhabditis elegans provides a reliable system to study various features, even among primates, because of its genetic tractability and invariant, compact nervous system (~300 neurons) that is known at the level of DNA sequencing. In addition, despite (and perhaps: because of) its compact nature, the nematode nervous system possesses a high level of conservation with mammalian systems

first contact with research on longevity came about when the work on the nematode Caenorhabditis elegans shuck the literature (Fig. 4.1). Long-lived birds, such as parrots (Fig. 4.2), constitute a privileged study field for senescence in animals. Several genomic features are unique to parrots, including parrot-specific novel genes and parrot-specific modifications to coding and regulatory sequences of existing genes, have been identified. Genomic features under selection in parrots and other long-lived birds, including genes previously associated with lifespan determination and several hundred new candidate genes, are now appearing in the scientific literature. Slow aging due to negligible senescence might be the clue in long-lived turtles. Justin Congdon has led unique longitudinal studies of two long-lived turtles on the E. S. George Reserve of Michigan State University, USA: Blanding’s turtle and the painted turtle (Chrysemys picta). In turtle populations, ages exceed 70, but the maximum lifespan of these cold-blooded reptiles with a bony or leathery shell is unknown. Both species mature slowly and begin reproduction after about 20 years, with a cohort generation time longer than 30 years. Remarkably, older females lay more eggs and have more consistent annual reproduction than the average younger adult. There are no outward indications of loss of vigor. As the longest-living rodent, the naked mole rat has been subject to the study of stem cell characteristics. Adult rats mobilize their red blood cells from both bone marrow and spleen. The animals reject senescence by maintaining youthful blood and

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Fig. 4.2 Parrots are intelligent and long-lived birds. Psittaciformes. Parrots. Subclass Neornithes, Class Aves. Order 22. This parrot with a stout beak has an upper mandible movable on the skull’s frontal bone, which lets him articulate words like humans. Parrots enjoy a long life (K¯ak¯ap¯o: 40–80 years). The gerontology of psittacines could reveal important insights into human senescence. Recent literature explores senescence in these birds. Stuffed bird (Ara chloropterus), Collection of the Natural History Museum Bern, Switzerland (NMBE) (Photo by Mrs. Nelly Rodriguez)

marrow single-cell transcriptomes and cell compositions until middle age (Emmrich et al. 2022). The animals maintain a prolonged cell cycle in vivo by keeping the metabolic profile low, but the lipid metabolism elevated. In general, vegetarian species live longer than carnivores, but the life expectancy of many species is ill-known. The earliest reversal of a growth timeline that we can figure out is seen with mammalian development, in which the embryo forms a blastocyst composed of a mass of pluripotent cells which give rise to any given cell type. At this early stage, implantation into the uterus takes place. Implantation can be retarded by maternal hormones inducing the blastocyst to secrete the protein‚ leukemia inhibitory factor (LIF), and enter a dormant stage. The astronomer Carl Sagan (1934–1996) puts it well “we are made of star stuff; we are a way for the cosmos to know itself”. We admire Sagan for amazing us about our universe and ourselves. Neither he nor the creation literature deals with senescence. Turritopsis dohrnii, the immortal jellyfish, is immortal because these animals are capable of reverting to a sexually immature stage living in colonies composed of

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solitary individuals upon reaching maturity. They are found in the Mediterranean and Japanese waters. Discoveries on fossils have opened our view on pterosaurs, the biggest, meanest, and most bizarre animals that ever flew, such as the carnivorous Quetzalcoatlus northropi. Quetzalcoatl was the king of all goods of the Toltecs who allowed no human sacrifice because he loved his obedient servants; hence, he admitted sacrifices only with snakes, birds, and lepidopters (insects, butterflies). Its mighty appearance has sparked modeling work in life-size such as recently done size at a Minnesota studio; winged dragons ruled Mesozoic skies for 162 million years. The animals lived and died in colonies, but there is no idea how old one individual lived. One should not succumb to the temptation of believing that animals in earlier times lived longer than animals nowadays. We have seen earlier that, e.g., Allosaurus fragilis, modeled at the LWL-Museum für Naturkunde, Münster, Germany, had a life expectancy of 25 years, and this stands for a long-lived saurian individual. The Westfälische Landesmuseum of Münster (LWL), Germany, nicely completes the exhibit at the Houston Museum of Natural Science, Houston, Texas, USA. This example suggests that individual life spans 230 million years ago and did not attain extremely long times before death. When U. Nydegger visited the LWL, he was impressed by the curator’s ambition to explain the creation of life: 1. With abiogenesis, all species created themself on their own, i.e., ab ovo. 2. With creationism, the Lord created each species according to his will. 3. Lamarckism (Jean-Baptiste Lamarck, 1744–1829) says that acquired properties during an individual’s lifetime could be given to the offspring—non-used properties/organs become stunted. 4. Georges Cuvier (1769–1832), the French naturalist, was convinced that species emerge/are destroyed time and again by deluges –> catastrophism. 5. Charles Darwin (1809–1882) proposed that all species have descended from common ancestors (allopatric speciation). 6. Synthetic evolution mixes the genomes of parent generations. Estimates based on currently observed reptilian growth rates, combined with the enormous size of dinosaurs, made one conclude they would live up to several hundred years. More recent studies make paleontologists believe that dinosaurs grew fast, and fossil studies show that thin layers of avascular bone form rings or growth lines like those seen in tree trunks. Counting bone rings under polarized light lets one obtain an estimated dinosaur’s age at death. Growth lines in dinosaur bones were first observed in 1983 in the study of Late Jurassic sauropod bones called Bothriospondylus, possibly from the herbivorous brachiosaur family, which was discovered more than a century earlier. The study caused estimates of its age to be revised, and it is now reckoned to have died at the age of 43 when only halfway to attaining its full adult length of 15–20 m. According to John Nudds, now a paleontologist at the University of Manchester, UK: “If you compare dinosaurs to present-day animals, we might expect that the very large herbivores—things like Brachiosaurs and Diplodocus, which were comparable in size to an elephant—would have lived, therefore, for 70–80 years; maybe a bit

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more. The smaller, meat-eating dinosaurs would have been more comparable to some of today’s larger birds, which are closely related. If you think of something like an eagle or raven, they live for 20–30 years, and that would probably have been the lifespan of a Tyrannosaurus”. Robert Thomas Bakker (*1945) is an American paleontologist who helped reshape modern theories about dinosaurs. Particularly by supporting the hypothesis that some dinosaurs were endothermic (warm-blooded). His seminal work, The Dinosaur Heresies, was published in 1986 (Bakker 1986). He revealed the first evidence of parental care at nesting sites for Allosaurus. Bakker was among the advisors for the film Jurassic Park and the 1992 US-American Broadcasting PBS series, The Dinosaurs. Crocodiles and alligators can withstand high radiation levels, reside in unsanitary environments, and successfully escape the catastrophic Creates-Paleogene extinction event. Likely, the gut microbiome regulates, as current research reveals, anticancer metabolism in these animals (Khan et al. 2019). The cryopreservation of humans who believe the future is not far away to become thawed and walk out on both feet will be discussed. Extinction might also not be forever since scientists of our time hope to resurrect a 50,000-year-old lion found preserved in the Siberian permafrost. Other research groups attempt to revive the ancient breed of a “supercow”, an Auroch, which died out in Poland in 1627, by breeding various cattle types and their offspring in a project launched in 2008. DNA can be extracted from fresh, mummified, or herbarium plants and organic material in milligram amounts. Thus, another project using DNA extraction and selective breeding to attempt the creation of a herd of foals is underway, foals similar to those of the quagga (Equus quagga quagga), an ancient relative of the zebra that went extinct in 1883. Dating back to the Cretaceous period—about 67 million years ago—Tyrannosaurus rex, a massive predator, lived to the upper end of the life expectancy of a Tyrannosaurus rex, about 28 years. (How do we know? After examining bone rings, scientists also determined that “Sue” had an adolescent growth spurt—gaining as much as 4.5 pounds per day—and reached full size at age 19). A bony model is displayed in the Field Museum of Chicago, IL, USA. The largest and best-preserved Tyrannosaurus rex, in the Field Museum of Chicago, is thought to have lived to almost 29 years, although it would have achieved adult size after 20 years. “Sue” is 12 m long from head to tail and estimated to have weighed around seven tons, underlining the rapid growth rate of such dinosaurs during their relatively short lives. The growth lines also guide a dinosaur’s growth rate at different stages of its life. It is now understood that most dinosaurs grew for a large part of their lives, with a remarkably rapid spurt during adolescence. The longest known lifespan of an animal is the Greenland shark, estimated to spread between 250 and 500 years; residents of Iceland enjoy its meat as a delicacy. So far, senescence research has drawn little information from this sizeable extant shark species.

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Despite rapid advances over recent years, many molecular and cellular processes that underlie the progressive loss of healthy physiology are poorly understood. Instead of looking at longtime extinct animals, current research efforts now focus on animals still being around. A single-cell transcriptomic atlas across the lifespan of Mus musculus, called Tabula Muris, more recently proposed a mosaic of cells including data from numerous different tissues and organs (Tabula Muris Consortium, 2020) (A single-cell transcriptomic atlas characterizes ageing tissues in the mouse 2020). Tabula Muris contains nearly 100,000 cells from 20 organs and tissues. Tabula Muris provides molecular information about how the most critical features of aging are reflected in a broad range of tissues and cell types. This project is a comprehensive analysis of the aging dynamics across the mouse lifespan; it includes single-cell and bulk RNA-sequencing of different organs across the mouse lifespan. It allows direct and controlled comparison of gene expression in cell types shared between tissues, such as immune cells from distinct anatomical locations. Please remember that lymphocytes recirculate. At one moment, the same cell is found in the gut endothelium, controlling the passage of antigens and commensal gut microbiota from the intestine into the bloodstream. A few moments later, this same lymphocyte guards food and air passages close to the amygdala. Combined with targeted genotyping, we can accelerate plant and animal breeding; marker-assisted selection/breeding or backcrossing can support trait mapping and could once provide deeper insight into the genetic control of senescence. With dogs, according to data from the American Kennel Club, the Bordeaux mastiff has the shortest life expectancy of 5–8 years, whereas the Coton de Tuléar species lives between 15 and 19 years. The bigger dogs grow, the shorter they live. It looks like the development of a large dog accelerates early in life, providing grounds for cancer development. 15 human years equals the first year of a mid-size dog’s life span. Dog age in human years is a popular topic for google searchers! Cell-specific changes occurring across multiple cell types and organs and agerelated changes in the cellular composition of different organs begin to be identified. Using single-cell transcriptomic data, cell type-specific manifestations of different creatures regarding aging, senescence, genomic instability, and immunosenescence changes will be quantitated. Once genome-wide association studies become the preferred approach to better understand aging, this author expects a biochemical definition of aging independent of using plants, animals, and humans or combinations therefrom as study objects (Fig. 4.3).

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Fig. 4.3 Sphinx. An old Egyptian Sphinx consists of a human head on a lion’s torso, thus combining human insights with animal force. Other statues of ancient Egypt connect humans and animals—the most impressive to the authors is the queen Tawaret (664–610 BC) from the 26th dynasty of the reign of Psametik (Photo by U. Nydegger)

References A single-cell transcriptomic atlas characterizes ageing tissues in the mouse. Nature (2020) 583(7817):590–595 Bakker RT (1986) The dinosaur heresies, 481p Emmrich S, Trapp A, Tolibzoda Zakusilo F, Straight ME, Ying AK, Tyshkovskiy A et al (2022) Characterization of naked mole-rat hematopoiesis reveals unique stem and progenitor cell patterns and neotenic traits. EMBO J 41(15) Khan NA, Soopramanien M, Siddiqui R (2019) Crocodiles and alligators: physicians’ answer to cancer? Curr Oncol 26(3):186

Chapter 5

Rejuvenation/Regeneration

Cupidus Rerum Novarum Cogitationes mortalium timidae et incertae adinventitiones nostrae et providentiae. The thoughts of the mortals are modest, their inventions and foresight are incertain. Empedocles, Wisdom, book IX, chapter XIV

5.1 A Button off May Turn on Something Else The possibility of rejuvenating fascinates us as much today as it did the ancient Greeks. In the story of Prometheus, an eagle was sent to peck his liver each day as punishment, while at night, it regrew. Another story, which we like, is from the Metamorphoses by Ovid (VII/227–262): Aeson, already close to death and frail by age and by years, ascribed stem cells a mythical character—part fact, a part fantasy which captures the imagination but also blurs reality and, for sure, attracts wealthy people. Regenerative therapies have a broad ethical background. Individuals are different—vulnerability and health politics get worried about financial impacts, including marketing and health insurance. At the same time, the advantage of curative gene therapy for rare diseases like Duchenne Muscular Dystrophy, restoration of independence, and reduction of healthcare costs is at stake. Zeus punished Prometheus for stealing fire and giving it to humans, which enabled civilization. Some believe that Prometheus obliged specific inquiry. A Lancet commission (October 4, 2017) thinks that the spark of regenerative medicine has become a flame that offers vast potential benefits, such as limbal stem cells licensed for corneal repair. But danger persists that are incompletely understood, and the best way to harness stem cells and genes to alleviate clinical needs remains unclear. Rejuvenation differs from regeneration: the former means going back, and the latter means going forth. We, therefore, must halt senescence and keep it on hold, perhaps successfully reverting aging. The communist manifesto of 1848 by Karl Marx and Friedrich Engels tells us: “The bourgeoisie, during its rule of scarce one © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_5

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hundred years, has created more massive and more colossal productive forces than have all preceding generations together. The subjection of nature’s forces to man, machinery application of chemistry to industry and agriculture, steam navigation, railways, electric telegraphs, clearing of whole continents for cultivation, canalization of rivers, entire populations conjured out of the ground—what earlier centuries had even a presentiment that such productive forces slumbered in the lap of social labor?” Where to locate rejuvenation—if it will come? The term “senescence”, i.e., the evolution of biochemical processes as time passes, comes from the Latin “senilis”, i.e., the “elderly” derived from senex, i.e., “old”, the comparative of which gives senior and the French “seigneur”. The adjective “she/ he is senile” describes behavior attributed to the elderly in the domain of morality. The world is on a roller-coaster ride from soaring hopes to shattered illusions to unbounded euphoria—rejuvenation nicely fitting in the three fields. Beyond the pleasure of writing up, this book arose a sterner demand for a particular rule of life in place of the rejected creeds. The sleepless sense that a new field of duty and motive needs to be restored in the void left by lost sanctions and banished hopes never ceases to stimulate our imagination. At the end of the eighteenth century, hope expanded into medicine to denominate the entire process of aging. To arrive at old age is defined by loss of vigor, increasing frailty, rising disease risk, and falling cognitive faculties. In the everyday language, it abusively denotes an elderly who has lost intellectual properties (Victor Hugo, 1802–1885), and purists say that “senile elderly” is tautologic. Senescent would then mean “someone who ages”, taken up in the nineteenth century by medicine. Senescence comes from the Latin senescens, -entis, the present participle of senescere to become old. “Pre-senescence” can be used to denominate the life stage immediately before senescence. Senior is an adjective and means first “the one who behaves gentlemanlike or adapted to her/his age” and is opposed to junior. Seniority finally means ancienneté, and those meant by seniority are in a privileged position compared to the more recent joint in. Most individuals in our circle of friends will answer the question: are you comfortable? With a “not always”. The psychological history and relationship with others leave space for emotional stress, which can dip quickly in one or another direction— happy or sad. One individual might be all too complacent, insecure, or trusting to accept senescence, albeit our modern way of life with the mobile telephone, now carried along on a wrist, calls for distraction, stimulation, excitement, or intensiveness. Looking out of the window of U. Nydegger at the bamboo in the garden at the end of the day calms him down, and he takes the chance to resume contact with a gentle solitary, thoughtful self that otherwise would elude him. The unpretentious simplicity of a balcony fosters our inclination to a tenderhearted version of happiness. Perceiving senescence, supporting it, and going through it might depend on subtle adaptation to sustain it. When senescence strikes oneself, and one remarks on it or is being told by others that you have become a victim of senescence, then the philosophical property of stoicism might help you deal with it. The philosophical tradition of the stoics, founded 2000 years back by Zenon of Kition in Athens (Greece), created ideas with tremendous insights into the human psyche—insights which keep their importance for us in

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modern times. Contributions from Cicero, Seneca, and Marcus Aurelius still help us in the twenty-first century to overcome the news that pre-dementia has (might have) stroken. The book written by Donald Robertson “Stoicism, and the Art of Remaining Happy”, explains the principles of modern therapeutic approaches and psychological resilience all by enjoying life at the same time (Robertson 2010).

5.2 Senescence and Religion Similar to the shift of senescence to ever older ages of lifetime, religion and beliefs have undergone changes historically anchored in modernity affected by commoditization, mediatization, and globalization of society and social life. Religions around the globe cannot escape consumer culture, electronic media, and globalization. We live in societies where aging, ritual, and social behaviors are under scrutiny; consumerism has become the dominant ethos, if not beliefs. This, of course, is fertile soil for research projects devoted to stopping/reverting senescence. In religions that practice voluntary divine service tolerate absenteeism from common ceremonies, one observes many seniors in churches contrasting to religions with strong customs of adherence to rituals. We cannot exclude that many church-goers become motivated to “come and see and to be seen” for fear of death—but this proves to be one’s own belief (Gauthier 2013).

5.3 Immortality at Its Best Reliability engineering, survival analysis, and other disciplines mainly deal with positive random variables, often referred to as lifetimes. A lifetime is entirely characterized by its distribution function as a random variable. A realization of a lifetime is usually manifested by failure, death, or some other “end event”. Jeanne Calment (1875–1997), the French supercentenarian, was the oldest person we know of—she was never transplanted nor rejuvenated, and we wonder which circumstances made her live that long. At least Madame Calment knew nothing about today’s eternal life fantasies. Like Exponential Medicine, Singularity University, futurologists like Patrick Delarive (*1962, a Swiss entrepreneur) who, admittedly similar to an Indian Guru, convincingly project additional life expectancy of, say, 30 years more. The Sens Research Foundation goes one step further toward immortality with the People Unlimited movement in Scottsdale, AZ, USA, which question the limitations of aging and death. There is always “an oldest individual” Mrs. Kane Tanaka just died at the age of 119 in her native city of Fukuoka (Japan); she was the 7th of 8 children and had 4 children; she said: my long life comes from good food and continuous learning. From now on, the French Madame Lucile Randon, with her 118 years, is the oldest person known in the world as of 2022.

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The fields of psycho-neuro-biology and biology under the auspices of people in the overlap between science and phantasy, like Ray Kurzweil (*1948) or Aubrey De Grey (*1963), promote and demand expertise for a field that has become much fashionable, also in Switzerland. Sophia Genetics and MindMaze, a computing platform that humanizes virtual reality, neuroscience, and machine learning in what they call “Health Valley” to distinguish their location at Lake of Geneva from Silicon Valley in California. The wealth management DECALIA Silver Generation group makes long life a field for long-term retirement plans. The discussion in Switzerland is open to pushing the retirement age far away from 65 years of age. Age segregation with loses its confinement the young to educational institutions, adults to money-bringing jobs, and the elderly to retirement homes. Senescence thus takes the aspect of remaining young. Cellular senescence is a stress-responsive cell-cycle arrest program that terminates the further expansion of (pre-)malignant cells signaling components of the senescence machinery—(genomics.senescence.info). The compounds p16INK4a, p21CIP1, and p53, and trimethylation of lysine 9 at histone H3 (H3K9me3) operate as critical regulators of stem-cell functions (which are collectively termed “stemness”). The most recent evidence for rejuvenation is linked to swarms of tiny living robots which self-replicate in a dish by putting loose cells together. These “xenobots” were first created in the year 2020 and taken from the embryo of the frog Xenopus laevis. These cells can form small structures that can self-assemble, move in groups and sense their environment—Xenobots self-replicate (Kriegman et al. 2021). Xenobots, named after the African clawed frog, are synthetic lifeforms that are designed by computers to perform some desired function and are built by combining different biological tissues. In a Xenopus laevis frog, these embryonic cells would develop into the skin. “They would be sitting on the outside of a tadpole, keeping out pathogens and redistributing mucus”, says Michael Levin, a professor of biology and director of the Allen Discovery Center at Tufts University and co-leader of the new research. “But we’re putting them into a novel context. We’re giving them a chance to reimagine their multicellularity”. In 2022, an aging-research initiative called Altos Labs was launched with several billions of USD from backers, including wealthy people. The anti-aging venture relies on reprogramming with Yamanaka factors: transcription information that can reprogram cells into an embryonic-like state capable of giving rise to different cell types. Studies in rodents and cultured mammalian cells have shown reprogramming leaving behind aging. The mystery, however, remains and awaits genomic confirmation. Californian valley, with the tech clusters in Silicon Valley, is now on the move in the rejuvenation field. Dozens of startup companies enjoy funding with vast amounts of Dollars for venture capital investments. Google founder Mr. Larry Page (*1973) believes in rejuvenation when he spends money to Altos Labs and a company named Calico, founded back in 2013 already. Blood plasma from young donors transfused into the elderly would retard senescence when we look at the Spanish company Grifols joining in the Alkahest adventure—and there we join old beliefs with new cells injected in Montreux, Switzerland.

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Facial rejuvenation (Fig. 5.1) would need several multimodality approaches to correct volume loss, thinning of the skin, and the sun damage that occurs with aging. Indeed, the collagen fibrils that provide strength become fragmented, and fibroblast connections become weak, leading to skin laxity and loss of youthful skin. By providing volumetric support, surgically applied fillers can produce a more youthful appearance. We cannot use a zipper-flipper on our skin. Still, synthetic fillers such as hyaluronic acid products, calcium hydroxyapatite, polylactic acid, and polymethylmethacrylate have bio-stimulatory effects. They range from minor effects on fibroblast production to prolonged stimulatory effects on the dermal thickness and blood supply. More recently, autologous fat grafting has become recognized as an ideal technique for facial rejuvenation because it is readily available, natural, and regenerative. Those not satisfied with life extension might be so by Alexey Samykin of the Russian Transhumanist Movement in Moscow and Danila Medvedev, the founder of KrioRus, which specializes in cryonics. Freeze a body hoping to revive it one day: the researchers think Russia will soon outpace other competing countries on anti-aging, biomedicine, and the fantasy of living forever. As the world becomes interconnected and consumers can exchange information in no time, they understand their wishes in the framework of an invented business ecosystem. As Alain De Button and John

Fig. 5.1 Facial stop of senescence. Aesthetic plastic surgery (i.e., cosmetic surgery) is a subspecialty of general surgery which takes advantage of biochemical insights into parts of the human body. It refers to procedures that improve the appearance of the face and body and helps severely wounded patients. Methods include abdominoplasty, breast augmentation, breast reduction, eyelid surgery, nose reshaping (rhinoplasty), facelift and removal, and addition of autologous fat. Plastic surgery draws its advances from other fields of medicine, e.g., transfusion, allo- and, lately, xenotransplantation. Graft rejection is rarely a problem

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Armstrong (“Art as Therapy”, Phaidon 2013) put it, the vast and sharp-eyed citizen armies of the Internet do the rest. Difficulties might turn into opportunities, and the redemptive elder mouse suddenly turns the wheel with accelerated speed—why not?

5.4 Suicide Albert Camus (1913–1960), in his “Le Mythe de Sisyphe” cites the greek lyric PINDARE (518–438 AC): “Oh my soul please do not strive for immortality, but rather exploit the field of all possibilities”. Camus introduces the chapter on “absurdity and suicide” by stating that there is but one severe philosophical problem, and this is suicide. As we write this book, many countries apply differential laws and orders, with suicide allowed in Switzerland (EXIT—Self-determined living and dying. www. exit.ch) but not in neighboring France; similar lawmaking applies to abortion surveillance according to gestational week. Swedish researchers analyzed a database of more than 185,000 individuals older than 18 years who had attempted suicide and who had been hospitalized during a period of 4 decades: life expectancy in women and men who had attempted suicide at age 20 was shorter by 11 and 18 years compared to the general population; for women and men whose suicide attempt took place at age 50, life expectancy was reduced by 8 and 10 years (Yasgur, Batya Swift, MA, LSW, Acta Psychatric Scandinavica, December 14, 2017). In quo enim plura sunt quae secundum naturam sunt, huius officium est in vita manere. (When a mans’ circumstances contain a preponderance of things in accordance with nature, it is appropriate for him to remain alive) (Cicero, De Finibus BookIII, xviii.)

It was realized before long that the aging process of the functional units of the human body, i.e., single organs, like the heart, liver, and kidney, or whole body interactions, such as hormonal regulations or coping with microbiota changes, do age at different time rates. Michel de Montaigne (1533–1592) writes: “sometimes it is the body which undergoes senescence first, sometimes it is the mind; I knew some people who developed dementia while their stomach and legs were still working nicely”. (original text: ‚tantôt c’est le corps qui se rend le premier à la vieillesse, parfois aussi, c’est l’âme; et en ai assez vu qui ont eu la cervelle affaiblie avant l’estomac et les jambes (Montaigne: De l’Age LVII, 471, Livre de Poche 1972). Therefore, if somebody says they are seventy years old, it remains unclear what this exactly would mean: is it the body, the mind, the soul, or all of the three? Hence, the older we grow, the more we develop a mosaic of differential ages within us. The remaining lifetime appears as an imprint: the life expectancy of men 81 and women 85 in Switzerland makes the remaining survival years probable of, say, a 70-year-old man 11 remaining years and of a 70-year-old woman 15 further years. Senescence is a multifactorial event, especially in mammals. The most diverse influencing factors have an aging effect on mammals, which we show in Fig. 5.2.

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Fig. 5.2 Senescence is a multifactorial event. Telomere damage, epigenetic dysregulation, DNA breaks, and mitochondrial stress are primary drivers of damage in aging. Several of these drivers of damage can induce senescence. Senescence can, in turn, drive the consequential aging hallmarks in response to damage: stem cell exhaustion and chronic inflammation. Other reactions to damage, such as proteostasis dysfunction and nutrient signaling disruption, are also integrally linked with the senescence response

The www.fusion-conferences.com of 2023 will feature a gathering of experts in regeneration and regenerative medicine in Cancun (Quintana Roo) Mexico. Looking at the preliminary program informs the conference participant which topics are currently in the limelight: • Role of growth factors in stem-cell biology • Extracellular matrix regulation of growth factor signaling in tissue repair and regeneration • Vasculature in tissue repair and regeneration • Immune system in repair and regeneration • Growth factor function in tissue repair vs. cancer • Growth factor-based tissue engineering for repair and regeneration. Incidentally, we must question part of the results presented at such congresses organized as a joint venture of scientific committee and tourist office. Declaration of conflicts of interest when presenting results arose 50 years ago as a topic and, unfortunately, so persists. We used to tell our students that there are three steps of satisfaction in research: (i) when the hypothesis is confirmed on the display of my lab photometer, (ii) when my laboratory animal reacts/behaves as predicted, and (iii) when other researchers confirm my observations. Only then are we working beyond science fiction, especially when looking at growth factor function.

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Regenerative medicine thus replaces, engineers, or regenerates human cells, tissues, and organs to restore, establish, and enhance normal function. The promise goes directly to the aim of health authorities to foster safe and effective treatments. It has a broad scope and includes cell therapies, therapeutic tissue-engineered products, human cell- and tissue products, and combinations between cells and devices, such as scaffolds around and upon which cells and tissues can grow. Current interest is focusing on adult stem cells to address various conditions. Hematopoietic stem-cell biology is now funneled into the development of treatments such as hematopoietic stem-cell transplantation (HSCT), which enjoys improved survival for patients with hematologic disorders (see also: Chap. 9). In many instances, yet widespread use of stem cells in techniques labeled as regenerative medicine is far from satisfactory. The HSCT approach for patients is highly complex, and backup with money from pharmacy industries is mandatory. To complicate matters, the term “stem cell” has been used to describe a variety of cells that can divide and differentiate, including hematopoietic stem cells, chondrocytes, and adipose-derived stem cells (mesenchymal stem cells, MSC). The mesenchyme, a tissue made from mesenchymal cells, is a very early phylogenetic structure, present already in the phylum Porifera, i.e., sponges. Between the two layers of flagellated collar cells (choanocytes) and the outer epidermis, a gelatinous mesenchyme unfolds, containing free cells, i.e., amoebocytes of several kinds and many minute crystal-like spicules. What zoologists thus see as early tissue, we medics see as a root element from which many different types of cells originate. But how do these filial cell types “know” where to go? Isabella Saggio tells a fascinating story (Saggio 2022). She was talking to Paolo Bianco (1955–2015) (www.eurostemc ell.org) and to Giorgio Parisi (*1948) (Nobel Prize, theoretical physicist), who were in contact for a joint research project on just this question: how do stem cells know what to become adipocyte, chondrocyte, where to go? How does an MSC know to help form my pinkie? And stop there? Ontogenesis at its best. Bianco and Parisi suggested following a project based on our knowledge on compartmental interactions of members of a group. As model compartments, they envisaged a flock of birds, say crows—how do they remain together? How does a lost crow find their flock again? Other compartments: Bacterial culture in the Petri dish or even a social group of individuals in a metropolis, e.g., lodges or we are not far from religious believer groups. To similar connectivities, definite cell populations continue dividing and growing, pushed forward by growth factors and inhibited to extend by inhibiting/locking principles: “bello, semplice e complesso” Saggio concludes her book chapter. Current progress in MSC research is impressive. There is a nomenclature explosion with these cells, e.g., with the term mesenchymangioblast wanting to say that this cell type bears the potential to go for endothelial, vasculature-prone tissue. Mesenchymangioblast-derived primitive mesenchymal cells have the potential to differentiate into mesenchymal stromal/stem cells, pericytes, and even smooth muscle cells.

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The potential benefits to human health have spurred significant progress in stemcell biology over the past several decades. The field has moved from the mere characterization of the properties of these cells to therapeutic applications. Despite the paucity of information from well-designed clinical trials, HSCT has been used in patients with a wide range of conditions, from cancer to disorders affecting the central nervous system, including Alzheimer’s disease. Severe adverse events and unproven efficacy often mislead doc and patients with the attractive linguistic designation “stem cell”. Should we go back to a comparison that comes to mind at this point? Many vital points from the twelve organ meridians used in Acu-Yoga lie along the Regulating Channels. The changes in the seasons also affect our internal conditions and needs. We are part of nature hence part of its changes. It is easier for us to be aware of the seasonal changes in plants and animals than in ourselves. Still, once we realize these changes, we learn to feel how strong they are—the season’s balance of growth and decay—between activity and rest. The plant life cycle illustrates blossom, seed formation, and fruit for the autumn—along this line, senescence seems to us as a stage on which blossom—seed—fruit perform, jumping directly to the next season. Spring returning then models the rejuvenation at the time of this writing, yet impossible to occur in humans. The image of a Holy Grail source for MSC comes to one’s mind if we dwell further into the existence of MSC. They remain a topic addressed by most specialties of medicine that endeavor cell-based therapies for a diverse range of diseases. More than four decades have passed since the formulation of a concept, initially at the time, that multiple connective tissues could emanate from a common progenitor or stem cell retained in the bone marrow. Improvements of obtention (cord blood, whole blood donation from donors supplemented with growth factors before donation, bioreactor recovered MSC) are still pursued—as they would help therapeutic efficacy. Such developments allow more profound insights into MSC physiology. When U. Nydegger left his job as CEO of the Regional Swiss Red Cross Blood Bank in 2006, the first publications on successful stem-cell transfusions became known. Until then, hematologists treated their malignancy patients with bone marrow-retrieved hematopoietic cells. Cell-surface marker analysis became known with the cluster of differentiation (CD 34+) marker at the forefront. Umbilical cord blood as an alternative to bone marrow as a source was competing, and since the first umbilical cord blood transplant in 1988, around 35,000 transplants have been performed worldwide. Fetal blood residual in the placenta after vaginal or cesarean delivery is a good source for stem cells with cell surface marker constellations not always defined. We believe the next 20 years will bring us a closer insight into MSC subpopulations, the term “mesenchymal” being much too imprecise and obsolete! The interested reader may consult the excellent review by Lanza and Seghatchian (2020): Transfusion medicine to join laboratory medicine regarding cell membrane receptor identification. Indeed, different degrees of binding will occur when ligands land on their cognate receptor—strong, medium, loose, transient, according to the specificity. “Loose & transient” are a recognition phase, during which the cell takes up information compared to solid binding and can decide the cell to fire off by ejecting cytokines: the “cytokine storm” is let loose.

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With organ aging, there are no linear, circular, or spiral patterns of senescence processes the more so as an individual may take influence her/himself on functional deterioration, such as practicing alcohol and other drug abuse, nicotine abuse, nutritional misconduct, or exposing oneself to a myriad of other harmful environmental factors, climate change included. Carbon dioxide (CO2 ) greenhouse gas increased from as low as 180 ppm during the Quaternary glaciation to a staggering 407 as of mid-2017. Arteriosclerosis and interstitial fibrosis are common involution expressions in most parenchymatous organs, but each has its distinct aging pattern. The aging of the kidney is well documented: a reduction in the number of glomeruli and a reduction of the glomerular filtration (GFR) rate are taking place along with a decrease in cortical volume, an increase of surface roughness and simple cysts forming here and there in the parenchyma. The GFR cutoffs below which kidney disease is likely to go back from 116 ml/min in the 20–29 years age group to 75 ml/min in the 70+ age group. Anything above is healthy: the typical glomerular filtration rate number is more than 90 ml/min and declines with age, even in people without kidney disease. The aging of the myocardium is subject to general conditions such as genetic mutation, persistent redox stress, overload, aberrant molecular signaling, DNA damage, and/or telomere attrition. As seen under the microscope, senescent cells can be identified because their membrane appears burst. They look elongated and deformed. Their DNA is deformed with loci, like INK4/ARF dystrophic. The beta-galactosidase in senescent cells makes them blue upon adjunction of acidophilic colors. Like this, entire tissues become identifiable, and they should not, if healthy, exceed the Hayflick limit. This limit explains the mechanisms that govern cellular aging: a normal human cell can only replicate and divide forty to sixty times before it cannot divide anymore and will break down by programmed cell death or apoptosis. Although still speculative, the Hayflick limit is now broadly accepted by those interested in senescence. Thus, beyond this limit, senescence is a welcomed phenomenon because it makes a place for rejuvenation, i.e., ingression of younger cells. Nuclear factor-erythroid derived 2-like 2 (NRF2), the key (gene-) regulator of the cellular antioxidant response, when activated, stimulates and is in line with exercise and antioxidant signaling. The intrinsic redox mechanisms and oxidative stress are widely studied in the myocardium to modulate cardiac myopathy and ischemic heart disease. They are an issue in organ preservation between donor and recipient. Skin aging is the most apparent and visible event in senescence, none the least with wrinkle formation and naevus parsemation. It has mechanistic aspects with keratinocytes as sensors. This organ is a treasure trove for many markers. Mammals cannot typically regenerate organs as efficiently as other vertebrates, such as fish and lizards. Now, scientists have found a way to partially reset liver cells to more youthful states, allowing them to heal damaged tissue faster than previously observed.

5.6 Artificial Organs (Distinguish Cellular Organs from Artificial Material)

55

5.5 Organ Transplants The possibility to excise an organ from a women’s or man’s body to insert it into the site it belongs (orthotopic) or at another convenient location where it finds place (heterotopic) has been possible since the 1950s when a kidney was transplanted from Ronald Herrick (1931–2010) into his identical twin, Richard, who survived for eight years (died 1963). The drug therapy to be followed by recipients not to reject the organ went and still goes along with the perfection of surgical and logistical procedures. The ethical caveats of organ donation are not solved and perhaps never will. In many countries with a sustained organ donor rate of 1/500,000 inhabitants (Spain, Italy, France), in Switzerland, this rate cuts in half, and we can only speculate why this is so. A straightforward option to become an organ donor in case of death is to carry an organ donor card. What remains here is the definition of death, which is almost as challenging to attain as the definition of health and normal. The diagnosis of “brain death”, issued upon detailed brain scans and other tests, is far from clear. Zach Dunlap (*1996) is the pilot case for this issue: Dunlap does not remember much from the day he died, but he does remember hearing a doctor declare him braindead. The SWISS LANDS is a local extension of the “International Association of Near-Death Studies”. The central issue is our aura of feelings—and each of us feels differently. Suppose the deceased person did not explicitly object to organ removal during their lifetime. In that case, countries like Austria keep dissent registries, and dissent solution applies, e.g., in Italy, Portugal, and Spain. Finland or Norway go as far as the next of kin can also object to post-moral organ donation: extended dissent solution. In Switzerland, we practice these cases with the consent solution (www. swisstransplant.org), but awareness for organ donation is growing in large parts of the population.

5.6 Artificial Organs (Distinguish Cellular Organs from Artificial Material) The market for artificial and synthetic organs has evolved ever since Maximilian von Frey (1852–1932) and Max Gruber (1853–1927) (both of Leipzig) developed artificial heart–lung apparatus for organ perfusion studies at the end of the nineteenth century (joalabe.wixsite.com/regenerative medicine artificial organs). At the Rockefeller lab in New York, NY, USA, Charles Lindbergh (1902–1974) and Alexis Carrel (1873–1944) were at the command of perfusion pumps that could keep an organ alive outside the body; the Carrel-Lindberg perfusion pump is exposed at the Smithsonian’s National Museum of American History, Washington DC, USA. Synthetic organs or organs grown from autologous bone marrow stem cells are under evaluation to make organ replacement therapy independent of donation.

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The field of transplantation remains a field that requires work despite being 70 years old but charged with many problems. Cells alone cannot survive in volumes greater than 0.3 mm3 . Nature solves this problem by branching. Tubular is another way to scaffold (urethral channels). Tissue biopsy (cells, culture, cells on biodegradable scaffold) is implant. The vascular system is a bioreactor. The same strategy for blood vessels: instead of stenting, a mechanical engineer becomes involved. The bioreactor allows flow-dependent endothelialization, and the body begins its job as a bioreactor. Skin is much easier because it has no tubular structure. Vaginal endothelial cells: the starting cell is the most decisive point. Artificial liver: take a vascular tree and infiltrate it with committed liver stem cells.

5.7 3D Bioprinting “This is our newest printer which we bring to the bedside. You scan the wound, then you go in, and the cells are layered: print skin” reports the research group led by Jeong et al. (2017). With the Leipzig apparatus, a thin film of blood flowing through heating and cooling chambers through sampling outlets, manually controlled by manometers, is permitted to exchange blood gases during perfusion. While such devices have opened the route for transient substitution, such as the extracorporeal blood flow while doing cardiac surgery, artificial organs are now used for permanent substitution listed in Table 5.1. Modern medicine is based on replicability. Since the advent of the germ theory in the nineteenth century, strengthened by findings from Louis Pasteur (1822–1895) and Robert Koch (1843–1910), medicine has taken an “if you can’t measure it, it does not exist” view. A long history of stigmatizing diseases made it impossible— or at least difficult—to readily measure signs and symptoms. Younger doctors are winding up with such features as geriatric assessment scores. The hip replacement was a breakthrough in rejuvenation—was the patient, before the intervention, confined to a cane, impaired in most physical activities; he again jumped around after the insertion of an artificial hip. Hip replacement needed a “light bulb moment” and getting there was painful, as Harvard surgeon William Harris (*1927) describes the setbacks on the path to a breakthrough collaboration that corrected a major problem in hip replacement surgery. John Charnley (1911–1982), the British orthopedic surgeon, ventured the first to miraculously restore pain-free movement and active lives to patients whose hip-joint arthrosis had made even the simple walk across the room difficult. He and Hansjörg Wyss (*1935), the Bernese Engineer, helped to develop the cuplike hip socket made of Teflon, known for its slipperiness. The top of the thighbone gets inserted at the end of a rodlike metal implant into its center, and the round head of the implant fits into the socket. Now researchers have created a new material that they believe improves on a decades-long drawback of artificial joint failure. The new material developed at Harvard-affiliated Massachusetts General Hospital (MGH)

5.7 3D Bioprinting Table 5.1 Artificial organs and transplants listed with examples of functional performance

57

Organ to be substituted

Artificial organ

Functional performance

Heart/lung

Extracorporeal circulation

O2 transport

Heart/lung

Mechanical circulatory O2 transport support Ventricular assist devices

Kidney*

Hemodialysis

Elimination of creatinine*

Beta-cells

Insulin pumps

Normalization of glycemia

Transient

Permanent Hip

Prosthesis

Deambulation

Heart valve

Biological/synthetic

Separation of arterial blood circulation

Ocular lens cataract

Silicone or acrylic lens Focusing power of vision

Myopathie Duchenne

Cardiac implant newborns

Organ to be replaced

Transplant

Heart

Entire heart

Blood circulation

Kidney

One kidney

Blood purification

Liver

Liver, or parts of it

Protein synthesis

Lung

One or two lungs

O2 uptake, CO2 disposal

Pancreas

Islet cells

Insulin production

Intestine

Digestion

Skin

Protection

Blood/ components

Platelets

Hemostasis

Bone marrow

Stem cells

Blood cell repopulation

Note Kidney*, creatinine* content of urine, among other metabolic waste products, is used to estimate kidney function

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will enable marathon runners, iron man, or else who need extra strong implants. (The Harvard Gazette 2007). The artificial organs available today are listed in Table 5.1. The cost of these new possibilities to extend healthy lives must be addressed. The insurance industry is slightly older than rejuvenating measures: In his recent book: LIFE (Polity Press, Cambridge UK 2018), Didier Fassin (*1955), the French anthropologist, tells us about the decisive moment in which the confrontation between the Christian ideology of sacred life and primacy of the human, and its economic rationale of monetary equivalent to life and hierarchy in the world of us humans. These are topics relevant at the World Economic Forum (WEF) in Davos (Switzerland), adhering to the principle that individuals pay regular premiums for capital accumulation. Life insurance begins to be felt as sacrilegious in well-to-do countries, none the least because to compensate for the loss of a father and a husband with a check to his widow and orphans. “The Mennonites went as far as to excommunicate those of their members who insured their life”, continues Fassin. Confronted with this virulent opposition, insurance companies worked to transform the image of their industry. The idea, or better, in our context, the fact that human life could become a monetary equivalent, gradually imposes itself. U. Nydegger was not surprised that the pharmaceutical industry produced life-saving drugs out of non-remunerated (Red Cross supervised) blood donation, such as albumin or the human plasma frontrunner, immunoglobulin, which made the companies rich (e.g., Sandoz©, Grifols©, Octapharma©, CSL Behring©, among the early ones). Here, we need to moralize the representation of capitalism among the public. Fassin would say: propose a form of transcendence of the financial world via an informative speech on the extended life expectancy of those individuals who behaved responsibly during their worldly life to leave resources to those who survived them. The novel “Homo Faber” by Max Frisch (1911–1991), who wrote much on responsibility and ethics, informs the reader about the life of a successful engineer working at the Swiss Federal Institute of Technology Zurich (ETH Zurich) and traveling to the Americas as a messenger of UNESCO. Written at a time when Silicon Valley, Artificial Organs, and transhuman thoughts were not yet in the limelight, “Homo Faber” still helps us to understand current developments with artificial intelligence and robotics. Along the same line, ETH Zurich hosts a Cellulose and Wood Materials Laboratory for Materials and Science (www.empa.ch). They distinguish MedTech from HealthTech, and by using wearables, they might open ways to modulate the senescence process at any stage.

5.8 Life Transplants Progress in storing food, especially meat, in the cold and/or frozen away achieved new public attention when the Nobel Prize for Chemistry 2017 was awarded to three researchers, one of them, the Swiss Jacques Dubochet (*1942), for their work on cryo-electron microscopy. Water molecules crystallize in a strictly regular mesh, one

5.9 Xenotransplantation

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molecule interacting with three others to form crystal. While cold calms down tissular metabolic/enzymatic processes and prevents bacterial overgrowth, freezing shuts them off. Freezing tissues has a longstanding experience with the blood transfusion community freezing away blood plasma at −20 °C or cryoprotected red blood cells. The Erythrocyte Freezing program of the British Army in Aldershot (Hampshire, UK) has been phased out and is improved by modern cryoprotectants, such as apatite nanoparticles. The work of Dubochet has now opened a procedure that accelerates freezing such that water has no time to form crystals, which destroy, at least in part, tissular proteins. They call their method “vitrification” of water: crystal formation at its best with translucency like glass. Such progress is currently spurring up cryo conservation science with many professional groups. In Switzerland alone, cryosuisse.ch, swisscryotherapy.com, and cryomedswiss.com are at work, and tissue preservation and biobanking are topics that occupy a sizeable part of expert meetings worldwide. Chemicals inspired by Arctic animals could keep transplant organs viable for longer. At the University of Warwick in the UK, proteins in some species of Arctic fish and wood frogs prevent blood from freezing, allowing them to flourish in extreme cold. Transplantation medicine forms a chapter on its own, inspired by transfusion medicine. Allotransplantation, i.e., transfer of an organ within the same species, and xenotransplantation, i.e., transfer of an organ among primates, are highly funded clinical research topics. A significant step ahead occurred in the late twentieth century when the HLA system compatibility became well controlled, and the ABO histoblood group differences between donor and recipient also began to be overcome. The average donor age is on the rise, and most transplantation teams consider grafts of elderly donors. Liver grafts from selected >70-year-old donors do not pose added organ-specific risks and thus have comparable transplantation outcomes. If such a type of transplantation becomes common, then the quantitative estimation of the senescence degree of a donor’s liver will become important. Many people ignore that one can donate an organ even if one grows old: in 2015, the oldest organ donor in Switzerland reached the age of 86 while passing away and giving liver and kidneys.

5.9 Xenotransplantation Animals as donors for organs to transplant in humans were briefly subsumed under the term xenotransplantation, which is now in its 6th decade of pursuit with everincreasing hope that it will work out well in a not-so-far future. Xenotransplantation is in line with encouraging findings which will eventually bring xenotransplantation to the clinic. With the introduction of galactose-α1, 3galactose (Gal)-knockout pigs, prolonged survival, especially in heart and kidney xenotransplantation, was recorded. One spends a long time to breed genetically engineered pigs, but advances in gene editing, such as zinc finger nucleases, transcription

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activator-like effector nucleases, and nowadays clustered regularly interspaced short palindromic repeats (CRISPR) technology, made the production of genetically engineered pigs all at a sudden easier. Today, the survival of pig-to-non-human primate heterotopic heart, kidney, and islet xenotransplantation reached more than 900, more than 400, and more than 600 days, respectively. The availability of multiple-gene pigs (five or six genetic modifications) and costimulation blockade agents speed up projects for clinical trials (Ekser et al. 2017). A unique venture in transplantation science is the San Servolo Island in Venice (Italy), hosting a consortium of 20 universities from all over the world: Venice International University. Here, science joins the global exchange of knowledge, having already produced several signs of progress, among them in the xenotransplantation area (Robert Rieben, PhD, University of Bern, Switzerland). This does not go without saying that life has no price; hence, the price one pays correlates with the insurance one can afford to pay; it is a horrendous vision to imagine despots who have reached 80 years of age returning to 60 years in good health.

References Ekser B, Li P, Cooper DKC (2017) Xenotransplantation: past, present, and future. Curr Opin Organ Transplant 22(6):513–521 Gauthier F (2013) Religion in consumer society, 268p Jeong YR, Kim J, Xie Z, Xue Y, Won SM, Lee G et al (2017) A skin-attachable, stretchable integrated system based on liquid GaInSn for wireless human motion monitoring with multi-site sensing capabilities. NPG Asia Mater Kriegman S, Blackiston D, Levin M (2021) Kinematic self-replication in reconfigurable organisms Lanza F, Seghatchian J (2020) An overview of current position on cell therapy in transfusion science and medicine: from fictional promises to factual and perspectives from red cell substitution to stem cell therapy. Transfus Apher Sci 59:102940 Robertson D (2010) The philosophy of cognitive-behavioral therapy, 318p Saggio I (2022) L’età, se esiste, 144p

Chapter 6

Overlap Senescence/Chronic Disease

Cupidus Rerum Novarum Aristoni et Pyrrhoni omnino visa sunt pro nihilo, ut inter optime valere et gravissime aegrotare nihil prorsus dicerent interesse Aristo and Pyrrho thought all things utterly worthless and said that there was absolutely nothing to choose between the most perfect health and the most grievous sickness Cicero De Finibus Book II, xiii

6.1 Ambiguity Between Two Different Medical Conditions Old age gets its way. It is challenging to be cavalier about a time of life marked by loss of vigor, increasing frailty, rising disease risk, and falling cognitive faculties. Many university-affiliated or foundation-based institutions have begun to study the aging human being with senescence as a background. Table 6.1 lists major institutions on the Internet, in newspaper articles, scientific papers, or in meetings. With the ongoing extension of life expectancy and the growing number of centenarians, research efforts are directed to explore the medical significance of changes in fitness, alertness, cellular, and humoral values of routine laboratory tests in the elderly. In Switzerland, each year accrues between 1500 and 1700 centenarians. The village Perdasdefugu (Sardegna, Italy) now counts 10 among the total number of inhabitants (1825), and the University of Cagliari, Italy lets its students do their thesis on the topic: what makes one grow to 100 years, which is the lead of senescence in this? Several medical diagnoses and conditions present in the elderly are either because they develop in the aging subject or because they persist and worsen from diseases present in younger age. Most studies published with centenarians as probands testify to relatively few overt diseases, such as cancer, hypertension, or endocrinological disorders (Jopp et al. 2016). This gives the impression that high age escapes us from a life-threatening illness, according to the earlier view of a survivor, delayer, and escaper (Lung et al. 2021) and Comprehensive Geriatric Assessment (CGA) scores used for cross-comparison with parameters not included in the score evaluations—all © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_6

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Table 6.1 Clinical and laboratory studies performed with elderly humans (selection) Study design

Initiated in

Continuously recruiting

Probands recruited by

Georgia Centenarian Study

University

+

Invitation

Yale Program on Aging

Medicine.yale.edu

+

Candidature

Iowa State University Centenarians

University

+

Invitation

Banner Alzheimer Institute University of Arizona

Private initiative

+

Baltimore Longitudinal Study of Aging

University

+

Candidature

PolSenior 2

Poland Government

− (approx. 6000)

Candidature

SENIORLABOR

University of Bern www.risch.ch

− (1467)

Invitation

DO-HEALTH

University of Zurich

− (2157)

Invitation

Note data drawn in part from URL sources are subject to change

too often addressing the neurological systems; Collin Ewald leads such research at the ETH Zurich (*1980). There are over 1000 diseases that the U.S.- National Organization for Rare Disorders (NORD) classifies as uncommon. Lifespan research now seeks to identify risk factors in early childhood that can cause problems later. Medicine performs checkups on admittedly healthy, well-trained individuals, often persons concerned with fears of falling sick: we find these fellow human beings in developed communities, often among vegans, non-smokers, vaccine refusers, antialcoholics who are looking at a lifespan perspective on how diseases emerge. Doing so opens the door for earlier diagnosis and intervention and the capacity to lessen the impact of disease when these people age. Nicotine dependence is a need for nicotine in individuals unable to stop using it. Nicotine produces temporary pleasing effects in the brain with the need for the next cigarette. The more one smokes, the more nicotine one needs to feel good. Trying to stop it induces unpleasant mental and physical changes: symptoms of nicotine withdrawal arise; but: regardless of how long one smokes, stopping will improve health (Fig. 6.1). U. Nydegger assisted with more than 150 autopsies back in the 1960ies. The smoker’s lungs were black even when anamnestic information told the pathologist that the deceased used filter cigarettes! Lung injury is now also recognized as an adverse consequence of mechanical ventilation in the workspace. Ventilator-induced lung injury can result in pulmonary edema, barotrauma, and worsening hypoxemia that can prolong mechanical ventilation, lead to multisystem organ dysfunction, and increase mortality, especially in workers who spend their professional life in ventilated, closed premises.

6.1 Ambiguity Between Two Different Medical Conditions

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Fig. 6.1 The Smoker. Werner Otto Leuenberger (1932–2009), a Member of the Berne Avantgarde Artists, often showing up with a cigarette, impressively depicts smoke (upper right corner of the painting), oil on canvas 1981, 100 × 80 cm (Copyright with the authors)

Post-traumatic stress disorder is a cluster of severe and persistent symptoms that follows exposure to prolonged trauma, and borderline personality disorder is a psychic finding characterized by unstable emotions that touches a patient’s selfimage and might mimic dementia. Estimated population-attributable fractions of large cohorts suffering from dementia showed that vision impairment and blindness are substantial risk factors for enhancing dementia. Biology is adapted to a given period or context, which might pay out later in life. Sometimes, the dead is already cast when someone enters old age from events that occur earlier in life. The aging process operates from the beginning of life. Ludwig van Beethoven (1770–1827) wrote the Mount Everest of violin concertos in D, OP. 61, in 1806, when the clouding of his deafness rose at the horizon of the master’s creativity. Many biological, social, environmental, and clinical issues are of great importance, but many unanswered questions remain. To some authors (for example, Martin Hürlimann (1897–1984)), the early-onset hearing loss of Beethoven made an otherwise caring personality to an introverted stiff and secluded individual, as Beethoven wrote himself: “oh, you humans who judge me hostile, stubborn and misanthropical how wrong and unjust you are. You ignore the secret reason for this appearance. From childhood onwards, my heart and senses were always benevolent, ready to do good all the time. As yet, for 6 years, the destiny of a hopeless situation has been imposed

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upon me: the poor performance of my sense of hearing—which I possessed early on at perfection—drives me crazy to the extent that more than once made me think of suicide. It is only my performance as an artist that holds me back—yelp—I felt it was impossible to leave the world before having achieved all projects and living a disabled life. Lord, you are looking down on my soul. You know it best. You are convinced that at my deepest soul, I love humans and that those who judge me recalcitrant ignore the injustice destiny impacts on me. Oh man, once you have read this, you will realize how you wronged me and the unhappy, by searching for peers attained by the same destiny, will hope to have achieved just in time before death strikes. Suffering condition: come early, come when you want, I’ll face you—good bye and don’t forget when I pass away, that I loved you sincerely to make you happy” Ludwig van Beethoven, 6 October 1802 (Heiligenstädter Testament). Upon aging, there is an incidence-risk shift from transmissbile to non-transmissible diseases. Minimal residual disease is a diagnosis essential to explore overlaps between senescence and chronic diseases. It’s not “minimal” at all! Originally of importance in therapeutic decision-making for our fellow oncologists in such diseases as multiple myeloma, we need to envision it mimicking premature senescence. Indeed, myeloma is a disease with pervasive genomic instability and clonal heterogeneity features, likely to also occur during senescence. Another door opened for those interested in genomics of senescence is the uprise of hematopoietic stem cells with age, which acquire somatic mutations: the new cell type is then subsumed under the heading CH. CH here does not mean Switzerland (Confoederatio Helvetica) but the abbreviation for Clonal Hematopoiesis, shown in humans to arise in individuals aged 40 years and older. In mice, CH starts in 2-year-old animals. Despite their differences in aged stem cells, mutations in aged mouse stem cells were distributed among similar genomic regions dominated by enrichment of C > T transitions at CpG dinucleotides (see Chap. 2). The usage of genetically modified mice with human-mimicking mutations in CH genes is about to become deeply studied. The non-transmissible chronic diseases such as cancer, cardiovascular diseases, kidney diseases, macula degeneration, and cataract may accelerate physiological senescence (Evert et al. 2003). The age of onset is a medical term referring to the age at which an individual acquires, develops, or first experiences a condition or symptoms of a disease or disorder. For instance, the general age of onset for the spinal disease scoliosis is “10– 15 years old”, meaning that most people develop scoliosis when they are between ten and fifteen years old. Diseases must be separated from habits, bad habits. From the postural appearance, one needs to separate everyday practices like clearing throat and to scratch one’s face. As the gaze or the voice is markers of our identity, composure and faulty posture must be listed as psycho-corporal markers of senescence. Astérix, in all cartoon drawings of this French cult figure, stands straight, young, and thriving, while Obelix or Gaston Lagaffe are curved back with their vertebral column evoking the elderly. Anthropological studies now reveal straight posturing as a feature of forwarding thriving, youth, and decision-making, while curved back would symbolize more sensorial, ponderal if not tired by years life style: senescence. Teeth grinding (bruxism), in

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some individuals’ expression of stress, and stress as a whole may dampen with years going by. The age of onset of mental health disorders has been found to be more challenging to define than physical illnesses. The symptoms of common mental disorders often start non-specifically. Pathological changes pertaining to disorders become more detailed and less fickle before they can be defined, say in the American Psychiatric Association’s DSM (Diagnostic and Statistical Manual of Mental Disorders) (www. psychiatry.org). Diseases are often categorized by their ages of onset as congenital, infantile, juvenile, or adult. The brain is a dynamic and complex system, constantly re-wiring itself. A major concern is what happens to the brain in earlier life that mirrors what occurs later in its psycho-pathological state. We here briefly make a cut from observational studies including healthy volunteers; there are two major procedures to recruit probands for such studies: by proactive invitation and by the candidature of the proactive invitation.

6.2 Examples of Senescence Studies To follow a few examples of early studies, mainly initiated in the United States of America (Table 6.1), which have served as models for an ever-increasing number of follow-up observations about the elderly.

6.2.1 Georgia Centenarian Study The Georgia Centenarian Study focused on the very old and attempted to describe how the personality traits of older adults are associated with components of successful aging (cognition, volunteering, activities of daily living, and subjective health). Three-hundred and six octogenarians and centenarians who participated in the third phase of the Georgia Centenarian Study provided data for this study. Tests factor was conducted to test the existence of two defined personality traits. Also, blocked multiple regression analysis was conducted to examine the association between personality traits and four components of successful aging. Results indicated that low scores on neuroticism and high scores on extraversion, openness to experience, agreeableness, and conscientiousness are significantly related to the components of successful aging. The likelihood of engaging in volunteer work, higher levels of activities of daily living (writing this book!), and higher levels of subjective health was also positively associated with cognition and engagement in volunteer work. We here allude to a pleasant aspect of senescence leading to a thoughtful activity precious for younger people in their quest for experience. Psychological elements open the door to representing examples of knowledge, insight, and know-how age provides with years, i.e., features young people are devoid of.

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6.2.2 Yale Y-Age Without large-scale planning and research-based interventions, our aging society will endure potentially intractable healthcare and socioeconomic challenges: this situation was referred to as the “Silver Tsunami”. The Yale Center for Research on Aging (Y-Age) is a growing interdisciplinary research program in Geroscience and the Biology of Aging with significant opportunities for program growth in the stimulating and interactive Yale environment (Yale University, New Haven, CT, USA). The research activities of Y-Age are focused on increasing our scientific understanding of the molecular mechanisms that control aging and translating those discoveries into interventions to promote healthy aging and combat common age-related diseases and pathology.

6.2.3 Centenarians in Iowa For this program, the Centenarians in Iowa, USA, any adult who will be 100 years old or older by December 31, 2021, and whose primary residence is Iowa enters the protocol. The Iowa Department on Aging rewards the individual. It promises its centenarian a profile on a Website consisting of their first name, picture, and fun information shared via the form: an original approach to accessing health data from the very old.

6.2.4 Banner Alzheimer’s Institute The Banner Alzheimer’s Institute and University of Arizona Health Sciences benefit from the Toole Family Memory Center at Banner Alzheimer’s Institute in Tucson, USA. It offers comprehensive services for patients and families and conducts research studies into the treatment and prevention of memory disorders. The memory center is named for the Toole family of Tucson, who donated $5 million to the Banner Alzheimer’s Foundation to bring the Banner Alzheimer’s Institute to Southern Arizona.

6.2.5 The Baltimore Longitudinal Study of Aging (BLSA) The BLSA is conducted by the National Institute of AGING (NIA) in the USA. Elderly, individuals may apply for a multitude of geriatric conditions. The BLSA’s longitudinal follow-up of a particular individual helps to evaluate an accurate picture of normal aging. Before the BLSA, one conducted cross-sectional studies. Most of

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the differences between these groups may not have been attributed to age but the result of life experiences, genetics, or environmental factors. Imagine comparing two people, one who has lived through two wars and the other who was raised in a peaceful and prosperous society. Each age might differ, but the effect of age alone remains challenging to sort out. By looking at the same individuals over time, external influences are reduced. Longitudinal research allows one to gather thousands of case studies of human aging.

6.2.6 PolSenior 2 This is a Polish nationwide survey of older Poles, their socioeconomic situation, and their quality of life carried out under the National Health Programme for 2016–2020, funded by the Ministry of Health. Under the project’s agenda, a representative—in terms of age, sex, and place of residence—group of nearly 6000 Poland citizens aged 60–106 is examined. The research methodology was based on questionnaires, analysis of various blood and urine parameters of the respondents, simple fitness tests, and measurements of parameters important for the health of aging adults. The scales and tests included in the Comprehensive Geriatric Assessment were also significant elements of the study. The results are published and disseminated in the form of a generally available monograph.

6.2.7 DO-HEALTH DO-HEALTH, initiated by Heike A. Bischoff-Ferrari, University of Zurich, Zurich (Switzerland), enrolled 2157 community-dwelling men and women >70 years and older (an age when chronic diseases increase substantially) from 5 European countries (1006 from Switzerland). Simple home exercise programs and/or vitamin D and/or omega-3 fatty acids were adhered to over 3 years. This study design allowed to test the benefit of the interventions in the prevention of 5 primary endpoints: • • • • •

The risk of incident non-vertebral fractures The risk of functional decline The risk of blood pressure increase The risk of cognitive decline The rate of any infection.

Critical secondary endpoints included risk of hip fracture, rate of falls, pain in symptomatic knee osteoarthritis, gastrointestinal symptoms, mental and oral health, quality of life, and life expectancy. DO-HEALTH seniors were followed for 3 years, in-person and in 3-monthly intervals (four clinical visits and nine phone calls) at the seven recruitment centers.

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6.2.8 Seniorlabor Study The observational SENIORLABOR study included 1467 healthy elderly >60 years of age from the Swiss midlands. Some results of this study will be shown in Chap. 9. Let us report here how we reasoned when initiating SENIORLABOR (Risch et al. 2017). When medical laboratory tests became part of practicing medicine in the mid1950ies, and the usage of automated laboratory tests became fashionable, the normal values of lab assays were established with healthy workforce blood donors. Early on, pediatricians taught us that children and young adults expose specific, age-related normal values—not only of endocrinological assays but also of standard assays, such as hemoglobin concentration, liver enzymes, and creatinine. It was thus logical and compulsory to question normal values, called reference intervals in the language of laboratory professionals (FAMH), of the elderly. Since then, many studies with senior individuals have been published and are going on with follow-ups. No doubt that further studies will line up none the least to develop drugs designed to alleviate frailty (Chap. 10). The distinction between senescence and disease, the separation, will be facilitated by budding technology adapted to eldercare. Monitoring devices will enable doctors to prescribe data-driven interventions, granting clinicians, and caregivers critical insight into the health status of the elderly they care for.

References Evert J, Lawler E, Bogan H, Perls T (2003) Morbidity profiles of centenarians: survivors, delayers, and escapers. J Gerontol Ser A [Internet] 58(3):M232–7. Available from: https://doi.org/10. 1093/gerona/58.3.M232 Jopp DS, Park M-KS, Lehrfeld J, Paggi ME (2016) Physical, cognitive, social and mental health in near-centenarians and centenarians living in New York City: findings from the Fordham Centenarian Study. BMC Geriatr [Internet] 16(1):1. Available from: https://doi.org/10.1186/ s12877-015-0167-0 Lung T, Di Cesare P, Risch L, Nydegger U, Risch M (2021) Elementary laboratory assays as biomarkers of ageing: support for treatment of COVID-19? Gerontology [Internet] 67(5):503– 16. Available from: https://doi.org/10.1159/000517659 Risch M, Nydegger U, Risch L (2017) SENIORLAB: a prospective observational study investigating laboratory parameters and their reference intervals in the elderly. Medicine (baltimore) 96(1):e5726

Chapter 7

Mosaic of Aging

Cupidus Rerum Novarum Nunc age, res quoniam docui non posse creari de nile, neque item genitas ad nil revocardi Now act, since I have taught that things cannot be created out of nothing, nor begotten brought back to nothing Lucretius: De Rerum Natura, I, 265–266

7.1 Manifold Senescence in the Same Individual Lucretius had accomplished a near-perfect integration of intellectual distinction and aesthetic mastery. Pieces are put together. Quintilian (Marcus Fabius Quintilianus (35-95 A.D.)) says: Neque enim quanquam fusis omnibus membris statua sit, nisi collocetur, et si quam in corporibus nostris aliorumve animalium partem permutes et transferas, licet habeat eadem omnia, prodigium sit tamen (For the fact that all the limbs of a statue have been cast does not make it a statue: they must be put together; and if you were to interchange some one portion of our bodies or those of other animals with another, although the body would be in possession of all the same members as before, you would none the less have produced a monster; Book VII, Pr 2-1 Institution Orgatoria). “In isolation, a puzzle peace means nothing. As soon as you have succeeded in fitting it into one of its neighbors, the piece disappears and ceases to exist as a piece. The two pieces so miraculously conjoined are henceforward one, which will, in turn, become a source of error, hesitation, dismay, and expectation” (Perec 1987). And if senescence is a piece of the puzzle? In an individual’s mosaic (Fig. 7.1)? When U. Nydegger was a child, his parents led him to visit one of the largest mosaics in the northern alp region: the ones preserved between Yverdon-les-Bains and Orbe-Boscéaz, Switzerland. These were laid out in Roman villas of wealthy residents about 170 years after Jesus Christ’s birth and often display rural motives; at which point U. Nydegger could not wait to travel to Ravenna (Italy) to there

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_7

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Fig. 7.1 Mosaic with title Star of Blues. Closely set, variously colored, small pieces of glass and beads. The human body resembles a mosaic in which each stone pursues its own senescence. Imagine the differences in histology and metabolism between organs such different as the brain and the liver. The gut endothelial cells are destroyed/rebuilt within hours—hepatocytes and different so, brain and nerve cells stay there much longer (Copyright from Uschi Schwärzler, mosaic artist)

admires the largest mosaics of the Byzantine rulers who decorated local churches with mosaics. U. Nydegger began to understand a mosaic when he came across Quintilian’s Institutio Oratoria, where Quintilian states that division means dividing a group of things into its parts. In contrast, the partition is the separation of an individual whole into its elements, the order of the correct disposition of things; what follows coheres with what precedes. At the same time, the arrangement is the distribution of items and parts to the places which it is expedient that they should occupy. But we must remember that arrangement is generally dependent on expediency. A theoretical and practical implication of mosaic aging is at work: 1. Although there may be relatively few mediators of senescence, such as oxidative stress or telomer length, the manifestations of these phenomena still are organspecific stochastic, and local. Hence, even if a single molecular biomarker is found to drive the aging process, this catalyst may not be homogeneously operational throughout all bodily systems, and its manifold effects thus may distribute in intricate and unpredictable ways. 2. For this reason, although we might identify a particular driver of aging, one should not necessarily expect a uniform aging pattern in complex organisms such as the human body.

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Thus, senescence is not a uniform process that progresses similarly in all parts of the mammalian body but affects the various systems in different individuals in different ways. Hence, despite diverse signs of senescence throughout the body, the untimely failure of a single feature (the “weakest spot”) often results in debilitation and death. The quest to identify the factors that regulate vertebrate aging is hampered by the complexity of the aging process, one manifestation of which is individual variation. This is a problem in humans, who are genetically diverse and subject to a vast spectrum of environmental influences. While we often refer to “aging” as a unitary phenomenon, each experiences a temporally and spatially unique constellation of physical and functional decline in complex organisms. This heterogeneity has been referred to as “differential aging” and is here referred to as mosaic because these changes affect different organic components at different times and rates. The skin is a unique stone in the mosaic of aging: actinic keratosis is more frequent in red-haired individuals with green irises. In U. Nydegger’s ancient Compendium of Anatomy by Andrew Fyfe (1752(4)– 1824) (Edinburgh 1823, 8th Edition), intended principally for students’ use, the first volume starts with the bones, “the hardest, compact and inflexible parts of the body”, as put it, Fyfe. The interconnectedness of living systems predicts that mosaic aging will engender a wide array of individual phenotypes, the bones representing a classic of senescence, i.e., osteoporosis. Another robust example of mosaic aging might be seen with menopause/andropause, i.e., models of physiological senescence occurring at different ages in different individuals. They are associated with many changes in hormones and behavior related to the loss of ovarian follicles and testosterone production. In the year 1921, the Innovation and Discovery Section, as chronicled in Scientific American, ousted a remark on the immortality for humans: “A skillful surgeon has kept alive, by artificial means, outside the animal, a bit of tissue from the heart of an embryo chick for more than eight years. The remarkable thing is that there is no doubt that if properly cared for, it will live on forever”. In connection with other scientists’ work, its meaning becomes clear: there is no apparent “aging” in individual cells. While we are theoretically immortals, the reason we are not so is that if one part of the body fails, there is a failure in other parts dependent on it, and the whole organism collapses. But it would appear that we shall continue to be young and vigorous so long as we can prevent a breakdown of any one part. Perhaps the day is not far away when most of us may reasonably anticipate a hundred years of life. And if a hundred, why not longer? Wilhelm Hofmeister (1824–1877) is credited for his focus on the alternation of generations in plants, a ground-breaking observational hypothesis that formed our modern understanding of the biological life cycle. More explicitly, a life cycle begins with birth and ends with the successful generation of offspring. Not so for modern medical understanding, which encompasses the course of stages through which an organism passes from fertilized zygote until maturity, reproduction, and, by extension, to death. Geriatrics, i.e., geriatric medicine, then is nothing else than relating the uncounted medical specialties to the care of elderly

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people. To continue with definitions, geriatrics and gerontology often use mutatis mutandis. Still, the latter is less medical and more general—encompassing hospital and home care and the biology of senescence as a whole. The ancient Greeks already had a word for the invisible building blocks, irreducibly small in size, unimaginably vast in number, things that could not be divided any further: atoms. In constant motion, atoms collide, moving according to what was later recognized as the Browns’ movement, and the atoms form larger and larger bodies. The largest observable bodies—the sun and the moon, are made of atoms, just as are human beings and water flies and grains of sand, as extends for us Stephen Greenblatt (*1943) (Greenblatt 2012). With mosaic, we must understand the variegated progress of aging and senescence in plants, animals, and humans. This happens on different levels. 1. Individuals of the same species may undergo senescence and/or aging at different intervals after birth. 2. Various organs of an individual decay at different speeds. 3. (1) and (2) can be sketched as in (Fig. 7.2).

7.2 Repair/Rejuvenation of Senescent/Aging Organs Senescence is as pervasive in organs as it is in tissues and paves the way for the removal of a diseased organ. Even a single organ may follow different patterns of senescence. In plants, leaves may senescence as part of progressive senescence, and older leaves are senescing as new leaves are produced. In animals, skin shedding is preceded by surface wear and tear, which we subsume under aging, the layer being replaced by additional cornified layers from the epidermis beneath. The outer cornified epidermis is molted at intervals by lizards and snakes, from two to six times a year by the latter. The production of a new cuticle beneath the older one means to repair. The rattle of rattlesnakes results from the retention of the heavier cornified covering at the end of the tail in successive molts. The Genome-Wide Disease Association (GWDA) studies taking senescence as a disease in IT search engines reveal 16 different loci associated with old age. Writing and reading on senescence require semantic unanimity between senescence and aging. Leopold put it right when designating senescence to represent endogenously controlled degenerative processes leading to death (Leopold 1975). At the same time, aging would encompass a wide array of passive or non-regulated, degenerative processes driven primarily by exogenous factors. Such passive degeneration, termed “aging”, is a consequence of wear and tear lesions accumulating over time and contributing to the mosaic allegory. Because the biochemical nature and the genomics of senescence and aging are not completely elucidated, it is premature to attempt a definition of these processes more deeply or to draw a line between them. At least one can state that the loss of viability in stored seeds is a clear case of aging. In contrast, the withering of petals following pollination and the postreproductive death of monocarpic plants are the effects of senescence (McKersie et al. 1988).

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Fig. 7.2 Each organ composing a human body features its own senescence. Exposure of each organ to stress, wear, and tear differs between organs. Guts never end working and are under neurological control of the Nervus vagus, an autochthonous nerve we do not control. The parasympathetic nervous system is a division of the nervous system that primarily modulates visceral organs such as guts and glands. The parasympathetic system is one of two antagonistic sets of nerves of the autonomic nervous system, in this ante posterior sketch imagined by Th. Lung, the Nervus vagus, the abundant abdominal lymphatic system, and the urinary apparatus are not shown

Fear of death is the cause of many of our vices; the soul, like the foot, is part of the body—the body and the soul are inseparably joined; the Jesuits decline the atom theory. If different stages of senescing organs cohabit on the same individual, we will perceive the resulting picture as a mosaic through a given time window. Acknowledging a mosaic of differential senescence in different body sites will make attempts to repair damage rather than slowing the dynamics of senescence more efficient to target. Organism in its diversity as an example—sandglass: the skin age faster than the liver or the brain—do they age in each one of us at the same speed? (Fig. 7.3). The authors were recently directing their interest to the liver, an organ, which by itself looks like a mosaic made from hepatocytes, gall-producing cells, fat tissue, and fibrocytes (Fig. 7.4). The joints are not in line with the pancreas, and the eyes (cataract, macula degeneration) age differently from the skin from the brain (Alzheimer’s Disease).

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Fig. 7.3 Human organs with their sandglass. The human body contains multiple alarm clocks, emblematized on this teaching slide to pertinent organs. The fastest one rings first, and the aging of the whole organism pushes frailty forward. Acknowledging such a system, geriatricians and caretakers can focus treatment and geroprotecting measures accordingly. (Imagined by A. Hemmerle)

The brain is a complex organ of highly active matter. Currently, hope is sparked that developing basic computer-assisted hardware will lead to a mechanistic understanding of the brain’s circuitry. But let us begin with a modern exploration of the brain: (Ehrlich 2022). The year 1873 is the moment when Camillo Golgi (1843– 1926), in his apartment near Milan (Italy), developed a new technique to color histological thin-cut tissues that revolutionized neuroanatomy: even a layman recognizes in the microscope the beauty of brain tissue, recoiling smooth and thin or thorny and thick black filaments as recalled Santiago Ramon Cajal (1852–1934). He was the first to show the many different cell types in the mammalian brain. He stained neurons to see them under his microscope and then made precise and beautiful drawings of their shapes. Among the few dozen types Cajal found, some had extensions—or axons—that reached out of blobby cell bodies like spiders’ legs over long distances. Some had short axons; others looked more like stars. He deduced that because the axons of each cell were very close to the cell bodies of others, they were probably

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Fig. 7.4 Different Organs age with different Rhythm—Example: Liver. As seen in the example of the liver, a whole array of senescent changes seen by cytological and tissular means are possible. The fatty liver, the fibrotic liver, the liver defending against infection (chemotaxis), the intracellular complement components (complosome), or the leukocyte infiltrates—either as single events or in a row

transmitting the information (1906 Nobel Prize in Physiology and Medicine). These structures remembered Cajal designs in Chinese ink on Japanese paper (Fig. 7.5) as appears in a Chinese fascicule that U. Nydegger brought back from one of his trips through China, a so-called Bodhisattva. The oldest printed book, a copy of the Diamond-Sutro (Tang Epoch) discovered in Dunhuang now exposed in the British Museum (London, UK), can be interpreted as a brains’ histology. Cajal declared that the utmost ideal of a biologist is to clarify the enigma of the self and the structure of neurons, he believed having found the consciousness proper and itself. He alluded to the design of neurons, whose birth, growth, decline (senescence forth, but not back), and death he studied with devotion and compassion, as though they were components of human beings: the mysterious butterflies of the soul. Hardly to be surprised to find that the structural complexity of the nervous system is gradually disappearing. The nervous system began to be thoroughly studied through its participation in embryology because axons grow and develop myelin sheaths—insulating layers of fat and proteins. Indeed, the nervous system can change, and that capacity is crucial to the organism’s survival. This will remain difficult. The brain cells’ framework remains a secret to us. There is nothing left to our ignorance of how things work, perhaps quantum physics. A consolation for our ignorance comes in our knowing that large assemblances begin to appear different from the behavior of their individual components. To put it like Stephen Hawking (1942–2018), the single neuron hardly portends those of the human brain, similar to the knowledge about a water molecule that tells us much about the behavior of a lake. This is the brain—of small laboratory animals up the evolution to humans. At the École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, we pursue the Blue Brain Project. The initial goal of the project, which

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Fig. 7.5 Deaf buddha. The twelfth Venerable Sakyamuni: those who only know the ear-picker knows the deaf Buddha, although there are right and wrong words, go in on the left and go out on the right. (An ancient Chinese text on Buddha cleaning his ears…, passers-by, who don’t know him, judge him as deaf and dumb, but he continues to ignore them and let the rumors go in on one ear and out in the other.) Courtesy: Janice Fuhrer

was completed in December 2006, was the creation of a simulated rat neocortical column, which some researchers consider to be the smallest functional unit of the neocortex. It is thought to be responsible for higher functions, such as conscious thought. In humans, each column is about 2 mm in length, has a diameter of 0.5 mm (0.020 in.), and contains approximately 60,000 neurons. Rat neocortical columns are very similar in structure but contain only 10,000 neurons and 108 synapses. Between 1995 and 2005, the types of neurons and their connections in such a column were mapped. The first artificial cellular neocortical column of 10,000 cells was built in 2008. A cellular rat brain had been planned and contained 100 microcircuits totaling a hundred million cells—a mosaic in itself. A cellular human brain equivalent to 1000 rat brains with a total of a hundred billion cells has been predicted to be possible by 2023. A developing brain with single-cell multi-omic profiling of human cerebral organoids constitutes a model to explore brain development. This can be achieved by single-cell transcriptome and epigenome data building a gene regulatory network, assessing the role of transcription factors in cell fate determination inducing, and then interpreting computer-assisted (artificial intelligence) single-cell CRISPR perturbations. In 2015, EPFL developed a quantitative model of the previously unknown relationship between the glial cell astrocytes and neurons. Some regard astrocytes as the immune cells of the brain. This model describes the energy management of the brain through the function of the neuro-glial vascular units (NGV). In 2017, Blue Brain Project discovered that network memory codes in the hippocampus connected to one another in more than one dimension. The project’s director suggested that

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the difficulty of understanding the brain is partly because the mathematics usually applied for studying networks cannot detect that many dimensions. The Blue Brain Project was able to model these networks using algebraic topology. In 2018, Blue Brain Project released its first digital 3D brain cell atlas, which provides information about major cell types, numbers, and positions in over 700 cerebral regions. In 2019, Idan Segev (Hebrew University, Jerusalem, Israel), one of the computational neuroscientists working on the Blue Brain Project, said, “Brain in the computer: what did I learn from simulating the brain”. In his words, he mentions that the whole cortex of the mouse brain was complete, and virtual EEG experiments would begin soon. He also noted that the model had become too heavy on the supercomputers they were using at the time and that they were exploring methods in which every neuron could be represented as a neural network. Cerebrovascular disease is the third most common cause of death in developed countries. Our understanding of the cells that compose the cerebral vasculature is limited. Recently, vascular single-cell transcriptomics provided molecular definitions for the principal types of blood vascular and vessel-associated cells in the adult mouse brain. Gradual phenotypic change (zonation) along the arteriovenous axis reveals unexpected cell type differences. A seamless continuum of endothelial cells versus a punctuated continuum for mural cells became apparent (Vanlandewijck et al. 2018). A healthy brain is at the origin of enjoying a productive human life. Environmental, social, occupational, and lifestyle factors influence brain health. However, significant variability between aged persons becomes apparent—those still with vivid alertness and those with lights out. Clinical reports and experimental data in animal aging models have shown that age-associated memory deficits are broadly identical to those induced by damage to the hippocampus. This brain region has a lot to do with our memory. The functional properties of hippocampal neuronal networks are particularly altered with aging. Whereas passive membrane properties of neurons are conserved with age, neuronal excitability is modified in keeping with the weaker performance of aged subjects in memory tasks. Synaptic transmission within hippocampal networks also decreases in brain aging. Deficits concern both glutamatergic and cholinergic pathways, which represent the central excitatory neurotransmitter systems responsible for neuronal communication in the hippocampus, a brain region that has a lot to do with memorization, possible cellular substrates for learning and memory, are also impaired in aging in correlations with cognitive impairments. Neuronal properties and synaptic plasticity depend on ion exchanges between intro- and extracellular compartments. Changes in ion regulation with years going by with senescence may alter the functional properties of neuronal networks. Calcium dysregulation has been extensively investigated in brain senescence, but the role of magnesium has received less attention because aging constitutes a risk factor for magnesium deficiency. One of the general properties of magnesium at presynaptic fiber terminals is to reduce transmitter release. At the postsynaptic level, it closely controls the activation of the N-methyl-d-aspartate receptor, a subtype of glutamate receptor, which is critical for the expression of long-term changes in synaptic transmission. Magnesium is also a

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cofactor of many enzymes active in neurons or glial cells that control neuronal properties and synaptic plasticity, such as protein kinase C, calcium/calmodulin-dependent proteins kinase II, and serine racemase. Therefore, a change in magnesium concentration would likely impair synaptic functions in the aged hippocampus. Experiments addressing this question remain too scarce, but recent data indicate that magnesium is involved in age-related deficits in transmitter release, neuronal excitability, and some forms of synaptic plasticity, such as long-term depression of synaptic transmission. The ideal strategy to slow down senescent processes in the brain is only found if holistic programs, including playing chess or collecting stamps, keep memory busy. More recently, sensory perceptions can be addressed on very short timescales (milliseconds to seconds) and how the individual turns these into decisions. Decide whether you can cross the street before the next car arrives; for most of us, this decision happens unconsciously using different sources of information, susceptible to senescent computational neuroscience.

7.3 The Senescing Memory and How to Measure Memory Attempts to measure memory go back to Aristotle (384–322 BC), but modern times have yet to reach conclusive measures. So, every school has its own set of tests uncovering introspection, i.e., the capacity to reflect and report the ongoing thoughts as yet an unreliable indication of the way our minds work for two principal reasons: (1) patients differ in what they appear to experience and (2) one is only consciously aware of a restricted proportion of the mechanisms underpinning mental life. The tip of the mental iceberg available to conscious awareness is not a good guide to represent what underlies beneath. So one must simplify experimental situations—experimental situations devoid of meaning but verbally learnable and reportable, inventing what has become known as the non-sense syllable, consonant–vowel-consonant combinations such as zug, pol, or mel. Results can then be interpreted as associations assumed to be formed between stimuli and responses. Another way to test is to read a short story to the patient, then wait a moment, read the first half of the story again, and let the patient complete it: do they remember? To compare one’s memory with the memory of your neighbor is difficult, but it is the only way to compare. There is also evidence that we fail to report memory lapses as we age. Complaints about the memory of the elderly can relate to depression rather than to loss of knowledge. Good, reproducible testing is needed to assess memory failure, especially because impaired memory is one of the earliest and most powerful predictors of the onset of Alzheimer’s disease, this gradual aging problem perceived in the Western populations. One of the usual outlines to study the aging-induced change in memory is longitudinal approaches in which one follows up a cohort of probands, selected to represent the full range of the population, say every 5 years, using the same tests. The rather mild loss of memory is impressively described in Ian McEvans’s (*1948) novel SATURDAY (McEwan 2006), in which the neurosurgeon Perowne’s mother no longer possesses the faculties to anticipate his arrival, recognize

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him when he’s with her or remembers him when he’s left. It is an empty visit. She doesn’t expect him and wouldn’t be disappointed if he failed to show up. It’s like taking flowers to the graveside—the real business is with the past. (…). Though she can’t put a name to his face, she’s content with him sitting there, listening to her ramble. She is content with anyone (citation finished). Cohorts of patients have the advantage that the effect of age on the performance of each participant can be appreciated, subsequently allowing to spot the individual who eventually develops Alzheimer’s disease (of which we have seen earlier that the ApoE4 is a risk factor). A reversal of the cognitive decline and silence at the doorstep of Alzheimer’s currently is the endeavor of many research groups worldwide (Fig. 7.6) (Bredesen et al. 2016). Dementia is not a dumbing down but a feyed silence. The deposition of β-amyloid precursor protein and phosphorylated tau-protein was regarded as definitive, irreversible damage to our memory for a long time. But more recently, Californian neurologists also perceived mild cognitive impairment as a metabolic enhancement for neurodegeneration (MEND). If this were true, even ApoE4 carriers would benefit from the MEND therapeutic program, described in 2014, and involves approximately 25 measures to keep a balance of metabolism (Bredesen 2014). Among them, we find as different as vitamin B12 intake and perhaps yoga sessions—we think at least established Alzheimer’s further awaits Fig. 7.6 Alzheimer’s Patient Lost in Reverie. This ‘Homme aux Champignons’, the title given by its artist, the Swiss painter Samuel Buri (*1935), depicts a transcendent human upper body and a head resembling a mushroom we here conceive as seen by disoriented patients of Alzheimer’s Disease (Serigraphy 1/9, property of U. Nydegger)

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targeted treatment. The MEND program encompasses some 25 measures to maintain a metabolic balance, but so far, it has not received worldwide recognition; it is an “all or nothing” program without exceeding healthy living. But: we are impressed and in light of medicine remaining an imprecise science, diagnostic and, to a certain extent, therapeutic reasoning remaining a complex iterative process. This must have guided the authors, who insisted on deepening the diagnosis of cognitive impairment. It must be so, we think, which brought the editorship of the prestigious New England Journal of Medicine (NEJM) to launch a new title series NEJM Healer (https://hea ler.nejm.org/)—a denomination we interpret to reflect and include clinical reasoning on a level, top scientists would qualify as imprecise. The promotional texts say, “clinical reasoning is difficult to assess”—if this remains true in the age of artificial intelligence, we must give the team around Dale E. E. Bredesen, eBook author and fully motivated to put cognitive impairment of senescence last, full credit unless prey of a relatively often encountered contradiction of motives of the researcher and the publisher—texts as marketplace commodities or gestures of self-sacrificing services. To conclude these critical comments, let us see what the Bostonians write: “NEJM has merged neuroscience and computer science for the most effective way to study (medicine)”. Cohort studies look at participants of people born at different periods to differ due to historical changes in diet, education, and other social dependents. Comparison of these test groups over time will provide a measure of any cohort effects while comparing them with the relevant longitudinal age group will indicate learning effects. Years of education are associated with memory performance, independent of age. The complexity of memory is evident when we realize that if you are asked to remember a long telephone number, then your pattern of errors differs depending on whether the number was heard or read. Implicit memory refers to situations where some form of learning has occurred but is reflected in active performance rather than overt remembering. To ride a racing bike, an e-bike or one of those new electro scooters are different movements, or reading a friend’s handwriting can be easy because we have frequently encountered the movement/writing style in the past. When John Steinbeck (1902–1968) finished what proved to be his last novel, The Winter of Our Discontent, he badly needed rejuvenation. His wife said: this trip across America was just something John had to do. And he wanted to go alone. He wanted to prove that he was not an old man, that he could take control of his life, drive himself, and learn things again—a fight against senescence. In “Travels with Charley”, he assumes that “A kind of second childhood falls on so many men. They trade their violence for the promise of a small increase of life span. In effect, the head of the house becomes the youngest child”. This lets the physiological expert distinguish long-term memory from explicit/declarative and implicit/non-declarative memory. Quite interesting is the invitation of software companies when it comes to learning the usage of an application, in short: “an app”: frequently used terms are “easy” and “fast” and “reading time: 3 min”. Elderly probands, although not in a hurry to comply, tell you that understanding the software algorithm brings them a more solid and persisting app usage. For this to achieve, we need preserved forms of learning as simple classical conditioning. Warrington and Weisskranz (1968) observed that

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word learning was preserved in amnestic patients when they presented them with a list of unrelated words and then asked them to recall the words in a different order. Mentioning the patient the first few letters of the presented words made them recall/ remember the entire word (Warrington and Weisskranz 1968). Recent years have brought a fast development of methods that allow the neuroscientist to record the memory operation of the brain in healthy probands at rest and when performing complex activities, including those involved in learning and remembering. Once again, when U. Nydegger learns to use software like Word or Excel, he needs to recall the first steps of the application while completing the achievement. Fortunately, learning in this field lets him complete his intentions in shorter time lags (see Chap. 1). Let us distinguish episodic memory, the mental time travel of Charleys from the more deeply stored memory called semantic memory. Senescence and brain aging are associated with declining cognitive performance and alterations in brain activity as measured by functional neuroimaging procedures. The sensory regions in the occiput are coupled with changes in higher associative areas in the frontal and hippocampal regions. Place cells, a population of cells in the hippocampus, represent our location in space and govern future navigation. Lifestyles, structural brain changes, and neurotransmission are most often found influencers of decline, and relatively explored white matter integrity loss adds up to mediate clinical pictures (Salami et al. 2012). Despite all the above-noted functional features, the functioning of the brain remains a mystery; it remains one when looking at the slow progress of the Blue Brain project (BBP), which started out using an IBM supercomputer on the campus of the EPFL starting in 2005. As if we humans would believe that the mysteries of nature can be solved using computers, some years later, the “in silico” experimentation based on twice the number of processors would help to imitate a neocortical microcircuitry permitting to acknowledge virtual brain tissue. The human brain as the basis for cognition is most developed in humans, so we think. Because brains are made of neurons, it seems reasonable to expect larger brains to be made of larger numbers of neurons. It follows that the computational units of the brain, made of larger numbers of neurons, should have more extensive computational abilities than smaller brains. The brain of Albert Einstein (1879– 1955) was analyzed post-mortem and found to weigh a few grams more than the comparison to a large number of male brains. We are so convinced of our primacy that we carry it explicitly, in the name given by Linnaeus to the mammalian order to which we belong—Primata, meaning “first Rank” and we are seemingly the only animal species concerned with developing entire research programs to study itself. The human brain has 100 billion neurons and 10- to 50-fold more glial cells and is endowed with an overdeveloped cerebral cortex, the largest compared with brain size. Some use this to explain humans’ superior cognitive abilities over mammals with even larger brains. Brains consume 20% of the total body energy budget despite representing only 2% of body mass because of a large metabolic need of its neurons. The BBP has now gone into reconstitution and stimulation of the microcircuitry in neocortical tissues, and researchers attempt a digital reconstruction of connectivity; they will aim to understand normal physiology with all that “normal” might mean.

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Aspectus animae ratio est.—The visual capacity of the soul is ratio. Augustinus, Soliloquia I, 13. partibus compositi sumus, ex animo scilicet et corpore.—we are composed of by two parts, the soul and the body. Augustinus Soliloquia I, 21. The textbook opinion goes that in contrast to most other tissue cells, nerve cells do not regrow, and the repair of nerve tissue is precluded. The exception is the hippocampus, with the regrowth capacity of its constituting nerve cells. This topic needs to be clarified since researchers in the group of Arturo Alvarez-Buylla (*1958) of the UCSF could not confirm regrowth (Sorrells et al. 2018). Brain from epilepsydiseased people or sampled during brain surgery, 59 in the number of babies, children, and grownups could not be repaired by adjunction of stem cells, HSTC. Better knowledge about risk and protective factors influencing brain health is the basis of preventing mental diseases and neurodegenerative disorders. In contrast, in Europe, we maintain the Lifebrain study integrating data from more than 6000 European research participants collected in 11 European brain-imaging studies in 7 countries; the study also gathers data on biological samples from some participants in the project. Inspired by these efforts, which initially focused on mice, in 2014, Japan launched its Brain/MINDS (Brain Mapping by Integrated Neurotechnologies for Disease Studies) project, a large part of which involves mapping neural networks in the marmoset brain. Since then, other countries, including Canada, Australia, South Korea, and China, have pledged to launch generous brain science programs with more-distributed aims. This work-in-progress is already generating colossal—and diverse—datasets, all of which will be open to the community. In December 2020, for example, the Human Brain Project (HBP) launched its BRAINS platform to provide access to datasets on various scales, the digital tools to analyze them, and the resources to conduct experiments. One of the most fascinating aspects of cognition is how the brain lets us perceive and navigate the world. When orienting ourselves, we constantly combine information from all six senses in a seemingly effortless way—a feature that even the most advanced artificial intelligence systems struggle to replicate. One of the most significant and best-funded efforts, bankrolled by the BRAIN Initiative, is a giant catalog of cell types created by the NIH’s Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative—Cell Census Network (BICCN), a consortium of 26 teams in US research institutions. The catalog describes how many different brain cell types there are, in what proportions they exist, and how they are spatially arranged. “Understanding the brain requires knowledge of its basic elements and how they are organized”, says BICCN member Josh Huang, a neurobiologist at Duke University in Durham, North Carolina, USA. “It’s our starting point for figuring out how a neural circuit is built and functions—and ultimately understanding the complex behaviors those circuits drive”.

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The BICCN is publishing several other papers across the Nature Portfolio. The consortium has mapped the cell types in around 1% of the mouse brain and has preliminary data on primate brains, including humans. It plans to complete the whole mouse brain by 2023. The maps already hint at small differences between species that could help explain our susceptibility to some human-specific conditions such as Alzheimer’s disease. Neuroscientists are particularly excited that the BICCN is building tools that target particular cell types and circuits relevant to infection, which will help to test hypotheses about brain function and to develop therapies. The cell catalog is a much-needed touchstone, says neuroscientist Christof Koch (*1956), president of the Allen Institute for Brain Science in Seattle, Washington. “Nothing in chemistry makes sense without the periodic table, and nothing is going to make sense in understanding the brain without understanding the existence and function of cell types”.

7.4 Type Hunter Over the decades, neuroscientists have used every suitable new technology that came their way to fine-tune the definition of what constitutes a distinct cell type in these classes. One realized that cells that superficially look the same could be different cell types, depending on their connections with other brain cells or regions or their electrical properties. At the same time, researchers were collecting data on how neurons connect in networks and what the networks’ properties are. When the HBP launched, it focused on generating the algorithms and computing power to help to simulate how these networks might function together. In the 1990s, researchers began to study genes’ activity in different cell types and how their expression reflected their properties. Still, the community wanted more. “We wanted to be able to see every gene that is expressed in every cell at the same time”, says Hongkui Zeng, director of the Allen Institute for Brain Science (https://alleninstitute.org). The different gene expression patterns in individual cells would allow researchers to define which type of cell they were—an ambitious task because the mouse brain contains more than 100 million cells, two-thirds of which are neurons. The human brain is three orders of magnitude larger, with more than 170 billion cells, of which half are neurons. A game-changing technology that emerged in the mid-2000s promised to help achieve this. Scientists have developed a way of sequencing RNA in single cells, a technique that has transformed all areas of biology in the past decade. A cell’s transcriptome—the RNA that represents a read-out of all its protein-coding genes— indicates the proteins the cell makes at a given time.

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7.5 Bigger Brains In the next phase of the cell census, the teams will focus more on larger brains. Some of this work has already begun. RNA sequencing of post-mortem marmoset and human brains has revealed remarkable consistency in cell types across species. What, then, accounts for the markedly superior cognitive power of humans? These studies’ central message is that cell types’ general blueprint is conserved across species. Still, you can find evidence for significant species specializations, even if they are just theme variants. The BICCN transcriptomic studies show a greater diversity of cell types in the human brain than in the mouse brain, particularly in the most recently evolved neurons. One corresponds to a class of neurons that is selectively depleted in Alzheimer’s disease. A kind of repurposing research project is given with research projects involving Alzheimer’s. When projects scrutinize abnormal amyloid deposits in the brain, they are obliged to explore the deposition site, knowing the microanatomy at best (Greenblatt 2012; Leopold 1975; Vanlandewijck et al. 2018; Sorrells et al. 2018; Noodén 1988).

7.6 Heart and Vascular Tree Arteriosclerosis with consecutive cardiovascular ailments such as blood flow blockade or aneurysmatic is a frequent killer. Adult stem/progenitors are a small population of cells that possess the potential to differentiate in all cell types of the organ in which they operate. Adult stem cells are implicated with the homeostasis, regeneration, and aging of all tissues and are now also used to treat inadequate oxygen provision of tissues. Tissue-specific adult stem cell senescence has emerged as an attractive theory for the decline in mammalian tissue and organ function during aging. Adult cardiac stem/progenitor cell (CSC) senescence has been associated with physiological and pathological processes encompassing non-age and age-related decline in cardiac tissue repair and organ dysfunction and disease.

7.7 Lungs Besides cancer of the airways, the lungs are not a primary organ targeted by senescence. Shortness of breath has many reasons, and personal training, jogging, or physical exercising makes us stop our efforts and get enough air. The mechanistic drivers of lung aging may be more readily understood, while the plain senescence of lungs independent of making long walks at high altitudes is poorly investigated. A patient seen by U. Nydegger who is now in her 80s and gradually developed a decline in lung function, increased gas trapping, loss of lung elastic recoil, and enlargement of the distal air spaces. She was diagnosed as developing the chronic obstructive

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pulmonary disease (COPD). The prevalence of COPD is two to three times higher in people over 60 years than in younger age groups. Indeed, COPD is now considered a condition of accelerated lung aging. Several mechanisms associated with aging are present in the lungs of patients with COPD: cell senescence is present in emphysematous lungs and is associated with shortened telomeres and decreased antiaging molecules, suggesting accelerated aging in the lungs of patients with COPD. Increasing age leads to elevated basal levels of inflammation and oxidative stress (inflammaging) and increased immunosenescence associated with changes in both the innate and adaptive immune responses. These changes are similar to those that occur in COPD and may enhance the activity of the disease. For the time being, she is treated with Prednisone and Symbicort 200 mg/d, a β-2 sympathomimetic often used in asthmatics.

7.8 Pleura The senescence of the pleura has yet to be looked at separately. This sheath was at the forefront of interest during the reign of tuberculosis. We remember this vital organ lining the thoracic space and covering the lungs of the patients hospitalized for tuberculosis in Davos, Switzerland. The senescence targets the glycosaminoglycan grease but without so far developing respiratory impairment.

7.9 Liver The liver has been addressed for senescence during the SENIORLABOR cohort of healthy elderly probands and patients with several liver diseases. Fatty transformation of both hepatocytes and in the portal trias, in the frame of non-alcoholic fatty liver disease (NAFLD), is a condition clinically often silent, which is quite frequent and by no means age-dependent. As yet, geriatric wards remarked early on that in individuals >65 years of age, upper limits of reference intervals of alanine transaminase (ALT) fall with increasing age (see also Table 9.1). As hepatopathologists often argue about interobserver variability, senescing transformation in liver tissue is observed only by performing a liver biopsy. A fibrosis score (FIB-4) and a NAFLD score are used in some clinics, but the thresholds in elderly patients are as yet to be defined. The ALT fall in older age is probably due to the increased fibrosis stage.

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7.10 Pancreas Two different components: the exocrine pancreas, a reservoir of digestive enzymes, and the endocrine islets, the source of the vital metabolic hormone insulin, make up this organ. Banting (1891–1941) and Best (1899–1978) discovered insulin production while satisfying their curiosity about the function of this gland using dogs. Human islets, called so because of their anatomical accumulation in the organ, possess limited regenerative ability and are subject to senescence, loss of islet β-cells in diseases such as type 1 diabetes, essentially an autoimmune disease with autoantibodies against the insulin-producing cell type. The leading strategy for restoring β-cell mass is through the generation and transplantation of new β-cells derived from human pluripotent stem cells. Here again, HSC could perhaps come the rejuvenate us avoiding age-associated Type 2 diabetes mellitus (T2DM). Other approaches include stimulating endogenous β-cell proliferation, reprogramming non-β-cells to β-like cells, and harvesting islets from genetically engineered animals. Together these approaches form a varied choice of therapeutic development for pancreatic regeneration.

7.11 Intestine The small intestine does not escape senescence which is more aging by lifelong usage. An elderly person suffered from lymphangiectasia and multiple protrusions of the colon into the peritoneal space (diverticulosis). Intestinal epithelial cell differentiation and maturation, usually a vivid turnover, slows down with aging. Intestinal villi, the capacity to absorb nutrients, are associated with senescence phenotypes. So, at least, the aging intestine loses support in the surrounding peritoneum, composed of connective tissue on its own. This applies to the jejunum, ileum, and colon, usually retained by collagenous stria. More recently, the microbial content within the gut, i.e., microbiota, has become the focus of interest. With stool transplantation, microbiota leads us to treat bowel disease, most frequently after radiotherapy, and in pediatrics, children receive maternal stool instillation to colonize their gut after chemotherapy. The gut is subject to a high renewal rate to replace damaged cells. Intestinal stem cells are constantly giving rise to progenitor cells which are prone to differentiate into the various cell types lining the endothelium. Faecalbacterium, Bacteroidaceae, and Lachnospiraceae were markedly reduced in the macrobiotic flora of the elderly.

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7.12 Diversity at Its Best An international study team of genome experts from China and Singapore has confirmed differential senescence velocities of organs building up the human body (Nie et al. 2022). So, the aging rate varies not only among human individuals but also among individual organisms. With such studies, statisticians plot organ-specific biomarker levels in the blood, urine, saliva, and other humoral fluids against time. One can observe organ-specific differences, which must be interpreted as a turnaround of multiple clocks within the body of a single woman or man (Fig. 7.3). When different sources/organs are addressed for the preservation of material to be examined, we must anticipate the fast progress of laboratory techniques. Thus, single cells are becoming exploited for RNA analysis in addition to RNA binding proteins (RBPs), themselves regulators of gene expression. Immunoprecipitation coupled to high throughput sequencing, such as RNA immunoprecipitation and crosslinking immunoprecipitation at binding sites across the transcriptome. Although aging is a lifelong process starting early in life, human aging studies are often conducted in older populations or cohorts with a high incidence of chronic diseases. Some studies could detect age-related changes from the early 20s, but the aging process in healthy young adults remains largely unknown. In addition, the organs of young adults usually are not yet heavily damaged, offering the possibility of preventing age-related diseases (Chap. 6). The selection of suitable biomarkers is essential for biological age classification (see Chap. 9), and many approaches have been implemented. Good studies utilize a vast number of biomarkers that comprehensively cover most systems of the human body in the same dataset for studying multisystem biological ages. Some diseases obturate biomarker designations, such as sarcopenia, for which we have nothing left but indirect measurements of limb contour, energy X-ray absorptiometry (DEXA), or bioimpedance. Therefore, as many biomarkers as possible must be selected from multi-omics approaches, and systematic evaluations of each measurement must be done. Statistical analyses can then be performed to calculate the role of aging effects of every biomarker, with redundant biomarkers being excluded.

References Bredesen DE (2014) Reversal of cognitive decline: a novel therapeutic program. Aging (albany NY) 6(9):707–717 Bredesen DE, Amos EC, Canick J, Ackerley M, Raji C, Fiala M et al (2016) Reversal of cognitive decline in Alzheimer’s disease. Aging (albany NY) 8(6):1250–1258 Ehrlich B (2022) Mysterious butterflies of the soul. Sci Am 50–57 Greenblatt S (2012) The swerve, 368 p Leopold AC (1975) Aging, senescence, and turnover in plants. Bioscience 25(10):659–662. https:/ /doi.org/10.2307/1297034 McEwan I (2006) Saturday, 304 p

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McKersie BD, Senaratna T, Walker MA, Kendall EJ, Hetherington PR, Noodén LD et al (1988) Senescence and aging in plants. Academic Press, New York Nie C, Li Y, Li R, Yan Y, Zhang D, Li T et al (2022) Distinct biological ages of organs and systems identified from a multi-omics study. Cell Rep 38(10):110459 Noodén LD (1988) The phenomenon of senescence and aging. In: Senescence and aging in plants, pp 2–50 Perec G (1987) Life, a user’s manual, 581 p Salami A, Eriksson J, Nilsson L-G, Nyberg L (2012) Age-related white matter microstructural differences partly mediate age-related decline in processing speed but not cognition. Biochim Biophys Acta 1822(3):408–415 Sorrells SF, Paredes MF, Cebrian-Silla A, Sandoval K, Qi D, Kelley KW et al (2018) Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults. Nature 555(7696):377–381 Vanlandewijck M, He L, Mäe MA, Andrae J, Ando K, Del Gaudio F et al (2018) A molecular atlas of cell types and zonation in the brain vasculature. Nature 554(7693):475–480. https://doi.org/ 10.1038/nature25739 Warrington, E. K., & Weiskrantz, L. (1968). A study of learning and retention in amnesic patients. Neuropsychologia 6(3):283–291. https://doi.org/10.1016/0028-3932(68)90026-2

Chapter 8

Remaining Life

Cupidus Rerum Novarum Nec enim umquam sum assensus veteri illi laudatoque proverbio, quod monet mature fieri senem, si diu velis senex esse For I have never asserted to that ancient and much-quoted proverb, which advises: “Become old early if you would (wish to) be old long” Cicero: De Senectute X 31-33

8.1 Look into the Rear—View Mirror “Always live so as every day would be last”. Katja Früh (*1953) asks herself how she would deal with this citation. Should we use the time to bring everything to order and dump compromising documents into the waste basket? Or should we listen to music and finish reading the book begun weeks ago? Or should we go to the best restaurant in town? What Früh wouldn’t do, at least, is morning calisthenics—for what so. The currently evaluated human lifespan results from an evolutionary and historical throughput time, from shorter-lived primate ancestors to today’s longevity human frontrunners, such as in Japan or Sweden. Right now, most human deaths occur at ages between the late 70s and early 90s. Father Gillenormand, 91 years old, in Victor Hugo’s “Les Miserables”, was one of those elderly men whom old age doesn’t hurt. Not passing away frightened him, but what worried him was the idea of no longer meeting his grandson. In The New Testament, Luke’s Book, we read in Chapter 21/9, “The Signs of the Times and the End of the Age”: for the things must come to pass first, but the end will not come immediately—in a slightly another context as an answer to the people who asked Him how long it would take until wars and commotions might arrive. When Wolfgang Amadeus Mozart (1756–1791) knew the restricted time of his existence, he would have spurred his productivity early on, right? Harvey C. Lehman (1889–1965), a psychologist at Chicagos’ University, published a series of studies that revealed the production of masterpieces, i.e., the most fruitful years for creative work, in the artists’ 30ies. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_8

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After this excursion into the New Testament, we certainly entirely ignore insight into the reason for the extension of creativity to later years, with the examples of Pablo Picasso (1881–1973) or Henri Matisse (1869–1954). Frailty in Matisses’ final years prevented him from painting—this French artist unleashed creativity in the medium of cutout paper collage. Matisse is cited for saying: “you need to keep the mental vigor of a child to sort things out”. Here, we need to distinguish between individual and cohort. The Gompertz law on human mortality issued 200 years ago was recently assigned to retain considerable relevance for studying the factors that influence the biology of aging (Kirkwood 2015; Gompertz 1833). Indeed, it holds potential insights into past, current, and future longevity. Among the factors which intervene, there is a significant agreement about the composition of food: Mediterranean diet, devoid of saturated fat and rich in proteins, is considered to withhold risk factors of premature death (Fig. 8.1). At least, the ultimate painting of Pablo Picasso, in fear of death, evokes an artist’s overcoming of fear of death. The other example of an artist who teaches us to overcome senescence, according to Ciceros’ headline from De Senectute, is the curriculum of Salvador Dali (1904– 1989). 30 years of a lifetime were filled with masterpieces to which he laid the

Fig. 8.1 Older men in a Sardinian Village (Italy) surrounding Central Square 1987. Photo: Copyright by wpw

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Fig. 8.2 Waterfalls’ bends waterflows time. Example of a painting with the topic time, memory, and flow—back and forth line. Sigrun Lung’s (*1943) Niagara Falls. Oil painted on canvas (2007). The viewer recognizes that time is an eternal cycle, like the continuous cycle of water that follows the flow of Niagara Falls

cornerstone when his career was carved out at the age of 27. The Persistence of Memory (see also Chap. 7) is an icon of the collective imagination and one of the most frequently referred masterpieces of Dali. This oil painting turns out to be surprisingly small (24 cm × 33 cm); because of its allure, mystery, and audacity and its referral to (Swiss?) pocket-watches, the observer tends to magnify its size to their imagination. This painting signifies thinking about senescence, proceeding or receding, and the contradiction and the inner greatness from an artist laying grounds to a career extending to his final days in the delayer age group. At age 65, Dali bought the castle of Pubol (Spain), and he became increasingly interested in science and holography, which opened up new perspectives of his constant quest to master three-dimensional images, in his case facilitated by progressive senescence. In addition to the famous painters of art history, many senior citizens today use painting as a hobby in old age to use their life experience and creativity to create beautiful works. Often, mysterious pictures are created, which, for example, depict the eternal flow of time in the image of a watercourse (Fig. 8.2). Is it possible that senescence fades unnecessary and remolding trains of thoughts away? At least, fading erotic sentiments let us focus more seriously on collaborations with the opposite sex, as the German philosopher Arthur Schopenhauer (1788–1860) repeatedly purported. Mammalian aging produces senescent cells, which cause chronic inflammation, which has entered the literature under the term inflammaging. A mathematical model, the Gompertz law of mortality in mice and humans, goes beyond data confirmed with senescent cell markers to explain the effects of lifespan-modulating interventions in humans and animals, considering scaling of survival curves and rapid effects of dietary shifts on mortality. The remaining and remaining life of plants depends on numerous factors such as genetics, environmental conditions, care, and much more. Plant aging is discussed in Chap. 3.

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Of profound interest, one uses the distribution of lifespans denoted by d(x), where x is age. Most demographers study populations large enough that d(x) can be treated as continuous, permitting the analysis of calculus, which has been recently published in a scientific text (Colchero et al. 2016) which one can quite easily understand without a university degree in mathematics. After a mortality hump in infancy, the proportion of dying declines with age and generally rises again in an old-age mortality hump. Females tend to live longer than males. A longer life? First of all: does someone wants it? If not, at which age do they see the ideal age to live the last day? Before addressing any decision problem under uncertainty, let us consider a preference function that evaluates the level of satisfaction with destiny and daily well-being. To put it with Christian Gollier (*1961), obtention of such a function makes decision problems most accessible to be solved with an outlook for a distinct decision that maximizes the decision maker’s level of satisfaction. We know that women live longer than men—calisthenics for the elderly, like the mom of coauthor Th. Lung (80 years old) complete the program of many a contemporary. Inner contentment can become to play an important role in containing senescence. In the Newlands Clinic, Harare (Zimbabwe), the original focus of Ruedi Luethy (*1941), was motivated to leave his post of professor for infectious diseases at the Zurich University Hospital treating AIDS patients. With this HIV-associated viral disease now treatable, the clinic, during the last quarter of a century, has specialized in gynecological care to bring the good medical practice to Africa (www.ruediluethy-foundation.ch). The laboratory medicine at Newlands is on the move. Well-being depends on a long list of personal good or bad decisions past and in future, which we can often quantitate for their appropriateness in the rear mirror. A psychiatrist practicing in Lausanne, Switzerland, recently proposed a constructive way to achieve good decision-making. Bertrand Piccard (*1958), in parallel, says that possible variables emerge which we can only influence indirectly and with effort: one’s health status, some meteorological parameters, levels of pollution, quantities, and nutritional quality of different goods available. Crowding of the planet and its local consequences at the place of living begins to list as a factor as well: the current high rate of population growth (https://www.worldometers.info/ world-population/) has been driven by the decline in mortality rates as a consequence of improved public health and rising incomes. One reason dignitaries, be it in the Vatican as popes or Royals or elsewhere, live longer than ordinary incredulous, or believers are the affordability of top-notch medical care. Mortality rates in developing countries have fallen much faster in the past decades than during the historical development of industrial countries. Other examples of longevity are Prince Philip, who died at 99, and his wife, Queen Elizabeth II of England, who died at 96. US President J. Biden is still doing a very responsible job reaching last year his 80th birthday. Stressful moments, sitting hours long in front of screens, and being overweight foster chronic inflammation doctors are now formed to cope with. Fertility rates have also fallen at an unprecedented rate but need to be faster to avoid a significant increase in the population growth rate. The literature and the knowledge on ideas concerning the age of marriage, births outside marriage, birth

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spacing, breastfeeding, and the use of modern methods of birth control are strong conditions by the behavior of other members of the community and with EXIT, Switzerland, ending life customs are allowed in Switzerland but under scrutiny in many other countries and cultures. The right to life is of paramount importance in international human rights law. Article 1 United Nations Charter; (Article 20(1)) alludes to each one of us a right to self-determination. Hurst Hannum (*1932) considers that “no contemporary norm” of international law has been so vigorously promoted and widely accepted as the right of all peoples to self-determination. Yet the meaning and content of that right remain vague and imprecise as when non-specialists enunciated them in social competence. Selfdetermination is a group right, and even Vladimir Lenin (1870–1924) wrote a book on the subject such that a tyranny of experts emerges, each of whose with their point of view: is the glass half-empty or is it half-full? Another group of Italian economists found that the 12th-century history still matters for values today: they claim that cities that were free in the twelfth century are more likely to have organ-donor associations today; ferent libenter homines id, quod volunt, credent (we tend to believe what we claim). Senescence of the hematopoietic system means slow-down of hematopoietic stem cell (HSC) self-renewal and myeloid skewing: risk for myeloid malignancies increases. Strategies to rejuvenate have life-extending potential—in other words, they slow senescence and bring the individual back to juvenescence. The delivery of young bone marrow endothelial cells and HSCs after total body irradiation improved HSC engraftment and enhanced survival. By rejuvenating these cells, it has been observed that transfusions of bone marrow endothelial cells from young mice promoted self-renewal and restored immune cell content in aged mice. Even more: young bone marrow endothelial cells improved hematopoietic stem cell engraftment and prolonged survival. These observations suggest an essential role for bone marrow endothelial cells in regulating hematopoietic aging and support further research to identify the rejuvenating factors elaborated by bone marrow endothelial cells that restore hematopoietic stem cell function and the immune repertories of aged mice (Chang et al. 2017). Could this discovery become a promising way to prolong the rest of life?

8.2 What the Future Might Hold (Kirkwood 2015) Avoidance of death is as old as the Egyptian culture preserving a person’s body or an animal after death. Mummification consists of drying and wrapping a body in linen strips, which last for thousands of years. Such preservation is worth its name because DNA samples can be obtained and scanned using polymerase chain reactions for several millennia-old genes. When death is inevitable, the afterlife not only offers mummification or a dignified position in a graveyard, conserved ashes, like in the song in “Mack the Knife” by Louis Armstrong and Ella Fitzgerald (“dust to dust and

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ashes to ashes”). There is another ash we should cremate, i.e., the digital traces on servers, The Digital Afterlife Industry. With an estimated 1.7 million U.S. Facebook users passing away in 2018, the digital graveyard is growing.

8.3 What We Know Up to Now Delivery of young bone marrow endothelial cells along with HSCs following total body irradiation improves HSC engraftment and enhances survival. This observation suggests an important role for bone marrow endothelial cells in regulating hematopoietic aging and support further research to identify the rejuvenating factors elaborated by bone marrow endothelial cells to restore HSC function and the immune repertories of aged mice.

8.4 What the Future Will Show (Kirkwood 2015) The LIFEEXTENSIONR (“stay healthy, live better”) company maintains a Lab Testing Service with close to 200 entries that try to quantitate the senescing process (dasatinib administered to older mice, young plasma transfer/pheresis, thymic regeneration GDF-11 restoration). Dasatinib being the trade name of a senolytic drug. Another company, life extension advocacy foundation, which Dr. Greg Fahy, attempts to rejuvenate the thymus to prevent age-related diseases. These are only a few possible tools to prolong the remaining life.

References Chang VY, Termini CM, Chute JP (2017) Young endothelial cells revive aging blood. J Clin Invest 127(11):3921–3922 Colchero F, Rau R, Jones OR, Barthold JA, Conde DA, Lenart A et al (2016) The emergence of longevous populations. Proc Natl Acad Sci U S A 113(48):E7681–E7690 Gompertz B (1833) On the nature of the function expressive of the law of human mortality, and on a new mode of determining the value of life contingencies. In a letter to Francis Baily, Esq. FRS &c. By Benjamin Gompertz, Esq. FR S. In: Abstracts of the papers printed in the Philosophical Transactions of the Royal Society of London. The Royal Society London, pp 252–253 Kirkwood TBL (2015) Deciphering death: a commentary on Gompertz (1825) ‘On the nature of the function expressive of the law of human mortality, and on a new mode of determining the value of life contingencies.’ Philos Trans R Soc B Biol Sci 370(1666):20140379

Chapter 9

Medical Laboratory Technology

Cupidus Rerum Novarum Nunc quae mobilitas sit reddita material corporibus How can we quantitate the movements of analytics Lucretius, De Rerum Natura Liber II pagina 94

9.1 Fire and Brimstone Sermon We were always fascinated by the fact that the same individual is simultaneously a mass of atoms, a physiology, a mind, an object with a shape that can be painted and photographed, a cog in the economic machine, a voter, a soccer player, or else. Laboratory medicine is a denomination that wants to encompass both assays proper and their interpretation with significance to the patient and their treating physician. Seen from the desk of the treating physician, medical laboratory test results are going to condition the appropriate therapeutic consequences. In vitro diagnostic (IVD) medical devices are now subjected to medical device regulation at the European (EU) and Swiss levels. They will come into effect with the Business Administration System for Ethics Committees (BASEC) submission form: “RESEARCH PROJECT APPLICATION FORM FOR MEDICAL DEVICES AND IN VITRO DIAGNOSTIC DEVICES” published in May 2022 in the Swissethics Newsletter. In the context of this book, however, we are looking for simple, elementary assays with results that are easy to interpret and with narrow reference intervals. So, hemoglobin concentrations in whole blood reflect morrow vivacity. Ferritin reflects the amount of stored iron. D-dimer, autoantibodies, bacteria determination with the clotting system mirror MALDI TOF spotting microbes, and ferritin are in focus in disciplines like hematology, immunology, microbiology, and clinical chemistry (Fig. 9.1). Laboratory medicine is a young discipline of general medicine. We wonder how much of med lab assays the surgeon René Leriche (1879–1955) depended on in Lyon (France) when he cut the intestines of Henri Matisse in the year 1941 for duodenal cancer—probably a few. The hemoglobinometer developed by Hermann © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_9

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Fig. 9.1 The FAMH wheel of specialties. From Clinical Chemistry with the often ordered ferritin, Immunology with autoantibodies, Microbiology clearing infections, and Hematology with platelets (thrombocytes). Each field is now increasingly governed by genetic exams

Sahli (1856–1933) existed already, and blood transfusion therapy had boosted development in the Spanish Civil War 1936–1939. At that time, the intervention by Leriche was successful, and Matisse survived later in a wheelchair. We humans are the same since at least back to Homo neanderthalensis came up. Depending on the source of information, the number of years backward when the fossil hominids lived varies considerably—in single cases, the numbers are rough estimates or even fake. Most species are rare findings with low numbers escaping statistical analyzes for significance. Hence, the analytes assessed in the medical laboratory today are basically the same: their phylogenesis dates back to our origins. The challenge of discovery is fascinating: discovery of the realm of nature. U. Nydegger has always read critically: “the researchers have discovered a new protein”. The “new” alludes to the discovery, but certainly not to the protein itself, old as the Neanderthal man! The author has seen this more particularly with proteins of the complement system: when Hans Müller-Eberhard (1927–1998) and his team discovered the C3 Proactivator Protein down in California, U.S., today termed factor B of the complement system, the writing read: “we have discovered a new protein”, and this “new” protein is now known to be present in the phylum of the Annelida (ringed worms) already. Colin Ronan (1920–1995), in his timeline analysis (“The Cambridge Illustrated History

9.1 Fire and Brimstone Sermon Table 9.1 Age-dependent deviations of reference intervals of routine medical laboratory parameters

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Elevated in the elderly

Decreased in the elderly

Alkaline phosphatase (ALP)

Creatinine kinase, eGFR

Cholesterol

Dehydroepiandrosterone

Clotting factors VII and XIII, D-Dimer

Testosterone, Oestrogen

Ferritin

Growth hormones

Fibrinogen

IGF-1, Interleukin-1

Postprandial glucose

Phosphor, Selenium, Thiamine

Parathormone

Tocopheroles (vitamin E)

IL-6

Vitamins B6 and B12

Noradrenalin, Parathyroid hormone

Vitamins C and D

Prostate specific antigen, Triglycerides

Alanine aminotransferase

Uric acid

of the World” Science), takes us through the steps which led to current laboratory technology, which matured through millennia and centuries. The flame of science began to burn some 10,000 years back in the Middle East: we read about the distinction between plants and animals, and in medicine, the midwife profession is testified very early on. Fascination further comes from the fact that paleontology has not arrived at its end since Egyptic Archeologists in Luxor discovered mommies 3500 years ago rubbed with ointment in a secret pyramid chamber. The chamber contains several mommies in clay recipients, adjourned with colorful inscriptions and grave seals. The ministry of antiquity in Cairo, under the heading of Khaled El Enany (*1971), is confident to discover more testimonies of Ancient Egypt—this book chapter is read by readers keen to find indications of medical laboratory. Table 9.1 shows the analytes we assessed in the SENIORLABOR study at the beginning of the twenty-first century. We bet albumin, thyroglobulin, and all others listed were the same in ancient Rome. Already in Old Egypt, blood was known to flow in vessels. What has changed is their recognition and designation. Let us start with the oath doctors swear at their graduation. In most countries, we address Hippocrates (460 BC). Long before the renaissance was coming up, we need to pay tribute to Roger Bacon (1224–1294), a Franciscan monk known under the acronym of “doctor mirabilis” much ahead of his time. Teaching in Paris from 1243–1247, he returned to Oxford and devoted a lot of time to mysticism and its channel alchemy. Karl Landsteiner (1868–1943) (Fig. 9.2), the Vienna pathologist and his team at the Allgemeine Krankenhaus, Vienna, Austria, were preparing bacterial growth milieus in Petri dishes and by mixing for this purpose human blood from different human

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Fig. 9.2 Stamp of Karl Landsteiner. From U. Nydegger’s stamp collection “100. anniversary Dr. Karl Landsteiners.”, Discoverer of ABO Blood Types (Austria stamp number 1296, Austria Netto Catalogue 1968)

donors observed that hemagglutination occurred with certain blood donor constellations but not with others: ABO blood type discovery was perfect. Landsteiner, thus, can be listed as a colleague laying the ground for laboratory medicine. The early development of pathology and laboratory services in the USA and Europe drew heavily on scientific advances and practices in medical schools and their teaching hospitals. The work of medical faculties in Germany and Austria was particularly influential. These developments—coupled with rapid advances in surgery made possible by anesthetics and the growing acceptance of hospitals as centers of care—influenced medical practice and the provision of services by hospitals worldwide. Hospital utilization was particularly stimulated by the development of clinical pathology and the introduction of clinical laboratory procedures, according to Dr. George Rosen (1875–1941) in his classic study The Structure of American Medical Practice: In the late 1870s in New York City, William H. Welch (1850–1934), T. Mitchell Prudden (1849–1924), and their students were the first in the United States of America to apply clinical pathology to medical diagnosis. Most hospitals had no laboratories. In the 1880s, when William Osler (1849–1919) was a clinical professor at the University of Pennsylvania Hospital, USA, he had the hospital’s only microscope and the state’s only blood counting apparatus. Even though bacteriological

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methods were available to aid diagnosis, they needed to be better understood and used by physicians. This was the critical step to tell physicians that patient care without lab assays would be incomplete; Gert Risch (*1937), the dedicatee of this book, said this early on. However, change was occurring. In 1887, George Dock (1860–1951) used funds from W. Osler and John Musser (1856–1912) to establish a laboratory at the University Hospital in Philadelphia. Later, at the University Hospital at Ann Arbor, he began giving all patients routine laboratory examinations, including urine and blood tests. Often, stomach contents, stools, sputa, vomitus, exudates, and fluids obtained by puncture were also examined. Similar developments were taking place at hospitals throughout the USA.

9.2 What the Future Will Show Handheld MALDI TOF, pulsed laser sweep-through high-power liquid chromatography (HPLC), is entering the field. Liquid biopsy initially developed for nextgeneration sequencing screening cell-free DNA (cfDNA) in peripheral blood specimens has gained access to routine for diagnosis by completing the information on tumor presence in tissue biopsies. Undoubtedly, the presence and extent of cfDNA in senescence are about to be studied using liquid biopsies of the elderly. Thus, the laboratory medicine field might contribute, at least in part, to a further extension of life expectancy. The recently coined term in medicine, biomarker, needs to be defined. Take prostate-specific antigen (PSA) or take low-density lipoprotein (LDL): are they biomarkers? We here would say so—their abnormally elevated levels announce damage, prostate carcinoma, and atherosclerosis. As yet, LDL is a bad boy, and it helps to induce atherosclerosis, whereby prostate-specific antigen (PSA) is a consequence of cancer development not caused by itself. When we develop a beneficial drug, say oxycontin, the pain killer, its success/ inefficiency ratio can be only estimated by pain relief, but there is no valuable biomarker that helps to prove its efficacy. Sarcopenia: the muscle tissue wanes away. Many naturally-occurring compounds from commonly consumed foods, such as nicotinamide riboside, tomatidine, and Urolithin A, possess anti-sarcopenic effects. These naturally-occurring compounds can improve mitochondrial health and efficiency by modulating mitochondrial biogenesis, cellular stress resistance, or mitophagy (see glossary). From the multitude of routine medical laboratory assays, a potentially meaningful set of assays needs to be assembled to best reflect sarcopenia in older adults or to define risk factors for amyotrophia in paralyzed younger individuals. Ill-known to good medical care such myocyte-related analytes as calpain, C-terminal agrin, 3-methylhistidine or cathepsin L genotype on FoxO3, blood plasma titin, urinary titin n-terminal fragment concentration (UTF), the extent of DNA methylation, and mitochondrial health are important metabolites in muscle health. They may qualify, save titin and its fragments, for

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quantitative estimation of sarcopenia. They have not been included on the test list of DO-HEALTH nor SENIORLABOR studies performed with healthy elderly individuals, whereas DO-HEALTH recruited 2157 adults aged 70 years and older from 5 European countries (1006 from Switzerland), the observational SENIORLABOR study included 1467 healthy senior adults >60 years of age from the Swiss midlands. Current efforts on diagnosing age-related sarcopenia are primarily limited to routine medical clinical parameters such as dual Energy X-ray Absorptiometry (DEXA) or bioimpedance and functional tests such as gait speed and grip strength. However, to motivate drug development in treating the now ICD-classified sarcopenia (ICD: International Classification of Disease), novel diagnostic tools that quantitate remaining muscular, functional capacity, and muscle mass, including its metabolic rate at rest, are needed. TAK1, a protein so far ignored in its activity, regulates skeletal muscle mass. TAK1 signalosome is activated in various conditions of muscle atrophy and hypertrophy. In mice, supraphysiological activation of TAK1 in adult mice stimulates translational machinery, protein synthesis, and myofiber growth (Roy and Kumar 2022). In a model adjusted for sex, age, treatment, and complications, surrogate-marker myoglobin above 60 mg/L may represent a hazard ratio (HR) of 2 for bedridden status; an even lower myoglobin serum concentration of 50 mg/L may become associated with an increase in mortality odds. Titin, also known as connectin, an abundant muscle protein along with myosin and actin, and found in circulating blood, currently sees convenient quantitative lab techniques being developed, some of them using MALDI TOF and ELISA combined to measure plasma concentrations in the mg/L range. Biomarkers of sarcopenia need to include basic metabolic measures, e.g., glycemia, hemoglobin, myoglobin, leucine, 25-hydroxyvitamin-D, ACE inhibitors (perindopril), cortisol, and LDH. To denominate a cell as a senescent cell, one needs to define the functional properties or markers that have been lost or acquired. Cell senescence induces interleukin release and identification of senescence-associated β-galactosidase (Saβ-gal) activity in tissues, detectable at pH 6.0, which is now known as a marker for senescent cells (Lung et al. 2021a). Expanding the Capabilities of Benchtop Flow Cytometers across a never-ending series of applications brought insights into membraneous or inner cell health—completed by differential color markers. Unexpectedly, a programmed component of embryonic development was identified using mouse embryos cultured on fertilized hen’s eggs. The caveats of examining Saβ-gal as an axiomatic marker for senescent cells have been outlined elsewhere. Markers for the senescence of senescent cells are manifold: the right constellation to denominate a cell as senescent is quite solid but not unequivocal. The daily pattern of laboratory tests in a doctor’s office counts a few analyzes, for example, creatinine, glycated hemoglobin, HbA1c, or ferritin, among others. The myriad of different surface structures on cells, surface proteins, and surface glycosaminoglycans can be used for cell allotment, typing, or distinguishing healthy from diseased tissues. In oncology and hematology, progress in proteome characterization is evident with the ease of accessing (leukemic) cells. The standard set of

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proteins used to deploy oncogenic perturbations in B cells, such as FLT3, NCR3LG1, or ROR1, may be profiled using genetically barcoded antibodies. Cell senescence is sometimes defined as the irreversible cessation of cell division capacity (proliferative arrest) of a given cell type. Human cellular senescence genes are accessible in databases (https://genomics.senescence.info/cells/), and the genetic background for cellular senescence does not appear to be controversial. Apoptosis, which was initially regarded as an isolated event that does not affect surrounding tissue, is now perceived as a response to stress and injury that causes the dying cell to secrete, upon death, mitogenic, and morphogenic substances that stimulate growth and repair in their surroundings. A cohort of dying (senescing?) cells must then be observed during normal development and in pathological conditions. Cancer and its treatment consist of stress factor-accelerating senescence. Modern treatment protocols, such as chimeric antigen receptor bearing T lymphocytes or combined cytostatic regimens, as well as early detection and supportive care, have allowed for an estimated 16 million cancer survivors in the United States.

9.3 Age Pervasiveness of Frequent Diseases 9.3.1 Health Tests Repeated, longitudinal medical laboratory workups (see Chap. 10), check-ups to identify people who are sick without signs or symptoms, and risk analysis of upcoming diseases are standard practices in developed countries worldwide. The major organ systems are screened with ideal lab analyzes and biomarkers using the 4 major sectors of medical laboratory assays, comprising clinical chemistry, hematology, immunology, and microbiology, embraced by genome sequencing techniques routinely in use. Whole-genome sequencing of microbial organisms may distinguish virulent from non-virulent and antibiotic-resistant from non-resistant varieties of the same species. Thus, it can be listed in personal big data banks, including microbiological pathology. The chronological age of patients suffering from definite nosological entities is best followed by consulting statistics on lethal diagnostics classified into age groups. A convenient classification can be made between survivors (age of onset of fewer than 80 years for at least one of the diseases), delayers (age of onset between the age of 80 and 100 years), and escapers (age of onset of 100 years or has not yet been diagnosed with a disease). It is well known that the very old succumb to cardiovascular disease due to myocardial aging rather than cancer. Lifetime diagnoses of 10 major lethal diseases (hypertension, cardiovascular diseases, diabetes, stroke, non-skin cancer, skin cancer, osteoporosis, thyroid condition, Parkinson’s disease, and chronic obstructive pulmonary disease (COPD)) were listed in centenarians and the original data published at the outset of the twenty-first century, revealing most of the 424 centenarians (aged 97–119 years) delayed or escaped heart

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disease, non-skin cancer and stroke, allowing survival into the > 100 years category. Most of these 10 lethal diseases are now under good medical and lab control. Because multimorbidity accumulates at high age, these observations must be taken as preliminary. Centenarians have successfully coped with age-associated diseases. Such is the case mainly for frailty (infirmity) syndrome, sarcopenia, chronic obstructive pulmonary disease, cancer, neurodegenerative diseases, macular degeneration, rheumatoid arthritis, and osteopenia which raises a hypothetical question: would senescence fence give diseases? The stage for successful aging can be explored by longitudinal follow-ups that aim to compare the health status of the very old to that of the same individual several decades prior. For example, the Georgia Centenarian Study allowed the separation of distinct morbidity profiles, of whom cancer struck centenarians in their sixties, cardiovascular disease in their seventies, and dementia in their eighties and beyond (Fig. 9.3). It remains speculative to derive from such observations that old age is a shelter for distinct International Classification of Disease (ICD) classified diseases. The survivor, delayer, and escaper avenues may be based on different centenarian genotypes that are useful to study factors determining exceptional longevity. Physical health factors that are considered to be risk factors in midlife could actually be protective factors in very late life, for example, body weight, blood pressure, and cholesterol levels (an easy and cheap lab parameter), as well as higher body fat, as noted in some centenarian research reporting such a paradox in physically healthy very old adults, particularly concerning hypertension. This observation fits well with the analysis of leading causes of death by age groups in Switzerland. The charts can

Fig. 9.3 Gross blend of frequent diseases and age groups of their predilection. The blurb positions are based on long-term international clinical observations; robust odds ratios are unavailable. Most of the depicted diseases occur at any age—the blurb positions denote a proclivity. We believe that individuals may have reached decency for which they are sheltered from a distinct diagnosis. The death reason recorded on statistical files is not reliable (Copyright from KARGER, Basel, Switzerland)

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be downloaded (https://www.bfs.admin.ch/bfs/de/home/statistiken/kataloge-datenb anken/grafiken.asset-detail.262901.html). With the extension of life expectancy, one assists in a chronological sequence of some frequent diseases shifting to the right, whereas some nosological entities do not affect the very old. The laboratory medicine community began scrutinizing reference intervals (RIs) applicable for validating assays ordered for older patients. Short lists of analytes are already available for RIs that substantially deviate from workforce age groups. It has been long known that sex hormones decline, and several parameters join an ever-growing list, often immediately upon initial recognition of their importance in improving diagnosis. The SENIORLABOR study initiated at our institution recruited 1467 apparently healthy elderly individuals >60 years of age; ongoing evaluations may be found at www.seniorlabor.ch. Our observations align with the previous studies of levels of laboratory analytes in different age groups and reference intervals, as recently summarized by Maria Edvardsson. SENIORLABOR is an ongoing prospective observational study, initially conceived to investigate reference intervals of a routine medical laboratory in 1467 healthy elderly study participants ≥60 years of age, allowed to focus on participant subsets to assess organ-specific laboratory assays (Table 9.4) (Lung et al. 2021a; Risch et al. 2018). Skin and neurological organs are of interest in the biology of senescence because we have learned how to monitor age-associated changes. Next, to wear and tear, skin senescence shows itself in the subcutis with the loosening of collagen fibers and reduced proliferation of cells in the basal cell layer. An age-dependent increase in the expression of the senescence marker β-galactosidase in dermal fibroblasts and epidermal keratinocytes is notable. So far, no link between skin senescence and immunosenescence has been found to portend that local, and organ-specific senescence prevails over systemic retarding of the course of senescence by recirculating immune or stem cells. For example, skin cells can be rejuvenated by transforming them into hIPSC. Hair follicle stem cells that are not contributing to epidermal homeostasis will exit their niche and participate in repopulating the epidermis: the Sartorius and Science Prize Winner, Dr. Yaron Fuchs has recently summarized such adjuvant repair features in his prize essay. This work allows one to understand the phenomenon of apoptosis as repair assistance: stress and injury lead to mitogenic and morphogenic features to stimulate growth and repair in the apoptotic cell surroundings; apoptosis is not merely a deadline of senescence but would bear potential for rejuvenation. Cellular senescence focuses on neural progenitor cells (NPCs) because its exploration might allow a better understanding of diseases such as primary progressive multiple sclerosis (PPMS): senescent cells are found in remyelinated white matter lesion autopsy tissue, and cellular senescence markers are found in abundance. This can be treated with rapamycin to restore primary progressive multiple sclerosis neural progenitor cell-mediated support for oligodendrocyte maturation. Thus, although MS was not previously perceived as a disease of old age, the growing segment of individuals aged ≥80 allows us to perceive a shift of multiple sclerosis into the elderly population. Senescent cells in the brain constitute novel therapeutic targets for treating agerelated neuropathologies. Senescent cells accumulate with age in various human

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and mouse tissues expressing a complex “senescence-associated secretory phenotype” (SASP). The SASP includes many proinflammatory cytokines, chemokines, growth factors, and proteases that have the potential to cause or exacerbate agerelated pathology, both degenerative and hyperplastic. While cellular senescence in peripheral tissues has recently been linked to several age-related pathologies, its involvement in brain aging is just beginning to be explored. Age-related neurodegenerative diseases are accompanied by increased SASP-expressing senescent cells of non-neuronal origin in the brain, corresponding to neurodegeneration. In the adult brain, cognitive and regenerative impairments have been subjected to experiments using heterochronic parabiosis, in which the circulatory systems of young and old animals are joined. β2-microglobulin has been observed to negatively regulate cognitive function in the adult hippocampus in an age-dependent manner. An imbalance of the 2 endogenous metals copper and zinc has been suggested to propel cognitive decline. More than any other organ, the brain exhibits extensive variation in senescence. In some people with early mental decline, different brachistochrone curves may be followed by steady holding periods. Long-term steady alertness may be forfeited only in late life. In both instances, similar mental cognitive test scores may result. Many believe that discrepancies between brain-predicted age and chronological age would reflect predementia for a given age. The University of Edinburgh Centre for Cognitive Aging and Cognitive Epidemiology has comprehensively reviewed these aspects and placed them in perspective to a series of biomarkers, including DNAm, telomere length, sphingolipids, and protein glycosylation extent. Age-related neurodegenerative diseases are accompanied by an increase in SASPexpressing senescent cells of non-neuronal origin in the brain, which correlates with neurodegeneration. It has been reported that the senescence of neurological tissue proceeds on its own and is independent of other organs of the same individual.

9.4 Metabolic Profile Down to their senescent state, somatic cells rely on metabolic energy expenditure; the metabolome impacts the epigenome with the potential to control cell fate. Glycation of proteins occurs in physiological systems to a low extent—typically 1–10 mol percent. Glycation by glucose forms N-terminal and lysyl side chain N-1 deoxyfructosyl residues or fructosamines, which are exploited clinically for the assessment of glycaemic control by measurement of glycated hemoglobin (HbA1c). A further major protein glycation type is methylglyoxal (MG)—a reactive dicarbonyl metabolite formed from intermediates. Methylglyoxal modifies proteins, misfolding, and inactivating them. Non-enzymatic glycation of proteins through the Maillard reaction is a physiological process, the extent of which impacts protein interactions with specific receptor (auto-) antibodies, protein half-lives, senescence, and

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protein folding. Thus, prediabetes, a pre-disease status, may be quantitatively estimated by measuring glycated HbA1c and fructosamine. Biomarkers that might best gage DALY (see glossary) are increasingly being explored (http://mortalitypredictor s.org).

9.5 Aging, Hallmarks, and Biomarkers Aging, the time-dependent deterioration of those physiological processes of the organism that support its survival and fertility, is complemented by senescence. This cue is better characterized at a cellular level by an irreversible cell-cycle delay. Definitions of aging are subject to discussion but also retain coherency with the view of aging due to the plateauing of natural selection forces. There is a long tradition of evolving views and theories of aging. Endeavors abound to conceptually clarify and theoretically contrast with each other the various theories such as evolutionary, non-evolutionary, programmed, and non-programmed. Harmonization efforts are underway, for example, using emerging new concepts such as the “deleterious”, unified mechanistic views, and the “somatic restriction theory of aging”, with the latter linking the “antagonist pleiotropy” theory to modern observations of epigenetics regulation in aging, potentially leading to clinical applications in regenerative medicine. The definition of aging and its theories goes hand-in-hand with a more sophisticated definition of “state of health”. Together with the concept of “absence of disease”, which is probably undergoing disuse and likely a too idealistic view of the state of “complete physical, mental, and social well-being” (WHO), the more recent concepts of homeostasis, allostasis, and “allostatic load” have emerged. They might better capture the organ and system dynamic adaptations to stressors and the environment by Laboratory Assays as Biomarkers of Aging, examining the capabilities of the organ or system when reacting to perturbation. Receptor-binding domains sensitive to the spike protein (S) of SARS-CoV-2 abound on respiratory lining cells; with the concept of allostasis, different types of organ resilience exceeds the lung—as exemplified by the liver with its “capability” to regenerate. Interestingly, there have been attempts to unify in a conceptual frame both aging and health, which might lead to precision prevention interventions. A broad spectrum of clinical manifestations, similar to systemic autoimmune disease, show off in SARS-CoV-2; this makes us believe that stress on the immune system is a prime pathogenic event in this disease. Despite the complexity of senescence, a small number of substantial molecular and cellular changes determine the hallmarks of aging, which bridge links to various diseases and can be potentially amenable to interventions. A short consideration of the term “hallmark” is necessary. Roget’s Thesaurus of English words and phrases (Kirkpatick B The original Roget’s thesaurus of English words and phrases. 1987. Longman, Harrow, Essex, GB) place the expression into its “means of communicating ideas” section. Hallmark is a label and a mark of identification, a sticker given to something we are not a hundred percent sure about this the way Carlos Lopez-Otin

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(*1958) and coauthors, in a Cell paper (López-Otín et al. 2013) proposed nine hallmarks of senescence: -genomic instability, -telomer shortage, -epigenetic alterations, -proteomic degeneration, -deficient metabolic regulation, -mitochondrial dysfunction, -cellular death, -stem cell deficiency, and -intercellular information hampering. All of these hallmarks were indirectly identified, according to three prerequisites: they had to be observed during the aging of the individual (lab animal, human being), and their experimental induction had to accelerate processes of aging and, accordingly, prevent the hallmark condition to proceed, keeping the individual away from senescence. More recently, the publications of Dr. Lopez-Otin have been challenged. At least, these interventions can be classified into broad categories such as systemic blood components and metabolic manipulations, potentially mimicking calorie or dietary restrictions, senolytics (drugs removing senescent cells), and cellular reprogramming. When search engines became fashionable, the European Informatics Institute linked its know-how to Logical Observation Identifiers Names and Codes (LOINC® ). Utilization of LOINC is now de rigueur in France, bound to integrate this language into the entire biochemical production chain. The complexity of senescence and its med lab seizure is doubled by the complexity of an ever-growing med lab number of possible tests. When the authors of this book entered the field of laboratory medicine a few decades ago, it was relatively straightforward to classify these tests into four major specialties, i.e., clinical chemistry, hematology, immunology, and microbiology, later to be completed by genomics. The necessity for metrics of senescence and aging with biomarkers goes along with the disentanglement of chronological and biological points in time. Chronological age (CA), anagraphic, and mathematical are disentangled from biological age (BA), a fluid measure of the degree of age-associated decline an individual undergoes. Within this scope, routine medical laboratory assays can be leveraged as part of modern high-throughput technologies for genomics, transcriptomics, proteomics, microbiomics, and metabolomics, hence contributing to the integrative analysis of biological events such as senescence. Ideal biomarkers should be able to predict individual age-specific mortality and age-associated pathology in addition to and better than chronological age alone. They should serve as metrics and risk factors. Such requirements also reflect challenges in choosing suitable biomarkers. As a biomarker of biological age is expected to be correlated to chronological age, one is tempted to use the highest correlation as a selection criterion. Still, one might also question the necessity of using a biomarker other than typical for chronological age. This conflict has been referred to as the “biomarkers’ paradox”. Applications other than geriatrics are forensic or racial in determining an unknown chronological age or assessing the state of health of a healthy individual or a patient. Moreover, as the biological heterogeneity in the aged population increases relative to periods of younger chronological age, a specific biomarker’s “positive predictive value” is expected to weaken. The biological causes or hallmarks of health include feature spatial compartmentalization, maintenance of homeostasis over time, and adequate responses to stress; disruption of any of these interlocked features is broadly pathogenic. The hallmarks can be grouped into primary, antagonistic, and integrative hallmarks, which impact

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both anabolic and catabolic metabolism and control longevity. For each one, specific biomarkers in humans have been proposed. The hallmarks of aging can also guide the development of biological age proxies, which have great potential for translational research in the clinical setting. Much work remains to be done, but several approaches might be implementable already. DNAm has recently emerged as the base of the socalled epigenetic clock. DNAm is interpreted as a specific marker of biological age, showing a strong association with multimorbidity, healthspan, lifespan, frailty, and mortality. The human immune system and its senescence (immunosenescence) are of paramount importance in aging. In a relevant study, multiomics technologies were used in longitudinally tracking over 9 years in 135 healthy adults. The data formed a higher dimensional trajectory marker (IMM-AGE) describing individual immune system status better than chronological age. A high inter-individual heterogeneity was observed, showing that each individual ages differently (Alpert et al. 2019). A particular note is required for “inflammaging” (chronic, sterile, low-grade inflammation), classified under the hallmark of altered cellular communication. Vegan food, abstinence, and Mediterranean food have been proven to reduce inflammaging. There are 4 lab assays recommended recently by Harvard Inflammation as a driver of aging, or “inflammaging”, which seems to be directly or indirectly caused by many of the hallmarks of aging, potentially capturing the global burden of the aging process because inflammation may be silent. The 4 assays are Erythrocyte Sedimentation Rate, C-reactive protein, ferritin, and fibrinogen: they are the 4 most common tests to explore inflammation. Efforts have been made to acquire well-known and new biomarkers to create indices of biological age. For example, symptoms, signs, key routine labs, disease classification, and disabilities were merged into a frailty index (FI) interpreted as a proxy of global aging. The frailty index, defined as “a ratio of the number of health deficits that individuals accumulated to the total number of deficits available in the database or a study”, was introduced in 2001 by Mitnitski and Rockwood and later developed by the authors (Mitnitski and Rockwood 2019). Along the lines of our tentative functional definition of aging, several panels have been defined by experts and include biomarkers of physiological, endocrine, physical, cognitive, and immune functions. One approach that seems particularly relevant to the authors is using the widely available, relatively inexpensive, standardized, and clinically validated routine laboratory analytes designed as biomarkers that are very similar to those used in the authors’ SENIORLABOR work. Additional information may stem from the ratio calculation of related analytes. These biomarkers, available in larger population cohorts, can be composited and analyzed to extract signatures of biological age, which can be compared with chronological age. In Fig. 9.4, we attempt to align a partial list of these med lab assays to detailed characteristics of cellular senescence (Lung et al. 2021a). Using data from the Long Life Family Study (LLFS) cohort, 19 routine laboratory biomarkers, namely high-sensitivity C-reactive protein, interleukin 6, N-terminal Btype natriuretic peptide, absolute monocyte count, white blood cell counts, red blood cell distribution width, transferrin receptor, mean corpuscular volume, hemoglobin

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Fig. 9.4 Alignment of elementary medical laboratory tests. A good opening of the data with the SENIORLABOR study would be predicting morbidity, if not mortality, with a set of simple med lab assays (Copyright from KARGER, Basel, Switzerland)

(Hgb), glycated hemoglobin (HbA1c), soluble receptor for the advanced glycation end product (sRAGE), adiponectin (Adip), insulin-like growth factor (IGF1), total cholesterol (T.Chol), sex hormone-binding globulin (SHBG), dehydroepiandrosterone sulfate (DHEA), albumin (Album), creatinine, and cystatin C, were able to identify signatures associated with essential aging-related physiological functions. To some extent, the data could predict changes in physical and cognitive function, survival, and risk of cancer, cardiovascular, and Type 2 diabetes mellitus diseases (Sebastiani et al. 2017).

9.6 Laboratory Assays as Biomarkers of Aging Morgan Levine used the Klemera & Doubal regression algorithm to predict mortality, which may be better than other algorithms and more informative (Levine 2013). The algorithms can also be improved by integrating biomarkers of different nature (e.g., anthropometric) in a single measure. Levine then established the concept of the “Phenotypic Age” and validated the association to all-cause and single-causespecific mortality, nosological entity counts, and physical functioning, all together predicting morbidity and mortality. Phenotypic age was calculated using chronological age (CA) and 9 biomarkers that are readily available in standard routine labs (albumin, creatinine, glucose, CRP, lymphocyte percent, mean corpuscular volume,

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red blood cell distribution width, alkaline phosphatase, and white blood cell count) using a Cox proportional hazard elastic net model for mortality and “parametrization of 2 Gompertz proportional hazard models—one fit using all 10 selected variables and the other fit using only chronological age”. Moreover, using data from the CHIANTI cohort and regressing the phenotypic age on blood DNAm data, Levine developed a new epigenetic biomarker of phenotypic age called “DNAm PhenoAge”. The phenotypic age was also recently included in a longitudinal examination of aging at the individual level showing various aging patterns or “ageotypes”. In a study based on 1013 participants in the Canadian Study of Health and Aging, a head-to-head comparison of 2 measures of biological age (BA) with 3 frailty indices (FI) was proposed, one of which was constructed from standard laboratory blood tests and blood pressure. One exciting aspect of the study was the non-inclusion of CA in the formulas determining the difference between BA and chronological age (CA). Relationships between aging, frailty, and mortality were further explored using a computational model based on complex network nodes (Mitnitski et al. 2017). In a recent genome-wide DNA methylation DNAm study using a slightly different analytical strategy, a new high-performance clock (called GrimAge) was designed by combining chronological age, sex, and DNAm-based surrogate biomarkers for a distinct selection of blood plasma proteins (out of an initial 88 measured by immunoassay) and smoking pack years (Rezwan et al. 2020). Epigenetic clock analyzes revealed severe COVID-19 was associated with an increased DNAm age and elevated mortality risk, according to GrimAge, further validating the epigenetic clock as a predictor of disease and mortality risk. An age-adjusted version of DNAm GrimAge was associated with various age-related conditions, lifestyle factors, and clinical biomarkers. It was shown to be particularly predictive of time to death, time to coronary heart disease, and time to cancer. As the number of biomarkers and different measurement technologies is expected to increase in the coming years, the use of artificial intelligence-driven techniques is also likely to augment (Fig. 9.5). Ten years ago, the SENIORLABOR study was designed to establish reference intervals of current medical lab assays suitable for validation performed in elderly patients (Risch et al. 2018). At the outset and upon immediate evaluation, the intervals of a large number of routine medical lab analyzes were calculated using crosscomparative data sets age grouping them from 60–69 years of age at study entry, from 70 to 79 years, and above 80 years of age. It was not until sometime went on that we began to work with follow-up observations without performing additional bleeds. The study, therefore, has not yet concluded since we sent questionnaires to the surviving participants in an endeavor to relate the quality of remaining life years to lab values determined at the outset. We here report part of the results and put them into the context of geriatric medicine. In most countries, the scientific surveillance of geriatrics in humans is of recent origin. Medical endeavors focused on life-extending measures mostly without follow-ups in medical laboratories, a field with recent extension. When we submitted the study protocol to the competent agencies in 2008, quite a few studies had already addressed the question of specific RIs in the elderly. The summary of the then-screened literature can be listed as shown in Table 9.4.

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Fig. 9.5 What innate immunity adds up. This figure lists numerous immunology tests which are currently (the year 2022) neglected and may reveal the large informative potential for certain diseases

During the last decade, many centers have scrutinized the accuracy of RIs. Many providers of analyzer modules for routine laboratory assays provide RIs for each parameter measured with a high degree of secrecy on how they were obtained. The sample size for healthy senior citizens qualified for non-diseased conditions makes that an inappropriately selected reference population may influence RIs. The sample size is also limited when group partitioning and filters for evaluation must be applied, such as for definite drugs taken, filtering for analytes linked to the one addressed, or partitioning by sex, age, ethnicity, menstrual cycle, or menopause/andropause passed (Miller et al. 2016). The statistical methods to establish the RIs once the data are produced, and nested analysis of variance (ANOVA) is the likely method of choice owing to its ability to handle multiple groups and being able to adjust for various factors. Outliers may be identified using Box-Cox transformation. Either RI or decision limit (“cutoffs”) is to be reported from the lab to the clinician but not both, according to a Clinical Laboratory Standards Institute (CLSI) guideline EP28-A3c requirement. The SENIORLAB cohort is plotted in Fig. 9.6. Looking at the age peak of the male/ female distribution, the longer life expectancy, i.e., relative frequency, for women becomes apparent in the SENIORLABOR study when compared to men.

9.6.1 Hematological and Related Aspects Hemoglobin concentrations: The hemoglobin concentrations we found in our SENIORLABOR study on healthy elderly probands are reported in: The hemoglobin

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Fig. 9.6 Seniorlabor study: age of probands. The participants of the SENIORLABOR Study, starting in 2008, were recruited by newspaper ads, chess clubs, mountaineering persons, and mouthto-mouth propaganda. They were taken up as probands for many med lab assays after passing a questionnaire with answers suggesting their health—at least: the absence of disease (Figure drawn by Wolfgang Hermann, Ph.D.)

concentration in an individual’s venous blood is a decisive med lab test on top of routine check-ups performed at any age. Even centenarians are tested. A human produces about 2 million blood cells per second, originating from hematopoietic stem cells HSCs. Over the age of 70 years, this production drops markedly (Mitchell et al. 2022). One may compare the oxygen-transporting dye hemoglobin with CO2 binding chlorophyll throwing a bridge from plants to animals. Concentrations below average can be anything, from lack of primary material for its synthesis to loss of blood or iron deficiency. In the clinics, the most common reason for overt anemia is excessive, often acute bleeding due to an accident or hypermenorrhoea. A case report recently published by the European Hematology Association in April 2022 brings us to the link of DNA repair: A 33-year-old woman was seen with pancytopenia (anemia, white blood cell, and platelet concentrations deficient). She had a vulval carcinoma treated with radiotherapy complicated by severe vaginal ulceration and perineal dermatitis despite standard doses of radiation. As a child, she was hospitalized twice due to severe neutropenia following a flu-like illness. She also has a horse-shoe kidney detected during staging investigations. A chromosomal fragility test revealed errors in DNA repair which thus became an evident way out of the senescence age group. Patients with Fanconi anemia classically suffer from urogenital malformations. The short stature, prominent forehead, widely spaced eyes, upturned nose, and underdeveloped mandible are further characteristics of this autosomal recessive disease first described in 1927 by the Swiss pediatrician Guido Fanconi (1892–1979). Fanconi anemia must be tested for using chromosome breakage in blood or fibroblasts or germline mutation analysis (see Chap. 2). Hematopoietic stem cell transplantation (bone marrow, cord blood, or peripheral blood stem cells) may cure aplastic anemia and prevent myelodysplastic syndrome or leukemia. At the time of this writing, one can estimate that so far, one and a halve million hematopoietic stem cell transplants

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have provided for continuous and differential improvement in worldwide access— with the use of non-identical family, donors have been performed—a new way to treat blood diseases unrelated to senescence—but when will senescence join in? To come back with diagnostics: the most frequent forms of anemia in workforce individuals are mild with hemoglobin concentrations between 100 and 120 g/l, often due to iron deficiency or bleeding. This is what U. Nydegger assumed when an elderly colleague medic called him and said: my hemoglobin value is 108 I told him: don’t worry, this is mild! Take a little dose of the then-available peroral iron, and 6 months later, he died. This case impresses us that mild anemias in the elderly are to be taken as a problem potentially announcing marrow failure, particularly combined with (also mild) thrombocytopenia (Tables 9.2 and 9.3). Table 9.2 Hemoglobin concentrations of the probands in the SENIORLABOR study in g/L Age group/ number

2.5 percentile

90% confidence

97.5 percentile

90% confidence

Outliers

Females 60–64/135

120

118–122

153

151–155

3

65–69/181

122

121–124

153

151–154

6

70–74/162

122

120–124

153

151–154

4

80–84/91

118

115–121

153

150–155

2

≥85/62

114

111–117

149

146–152

4

Males 60–64/129

135

133–137

167

165–169

3

65–69/159

135

133–137

167

167–171

1

70–74/117

137

128–133

170

176–172

2

75–79/110

127

124–130

166

163–168

2

80–84/79

125

121–129

171

167–174

2

≥85/37

116

112–121

160

154–166

0

Table 9.3 Reference intervals and median values of platelet concentrations (×109 /l) found in the SENIORLABOR study Platelet concentrations (×109 /L)

Median concentrations of platelets (× 109 /L)

95% CI 60–69

152–380

230

95% CI 70–70

135–351

228

95%CI > 80

128–350

223

90%CI 60–69

162–330

ND

90%CI 70–79

148–331

ND

90% CI > 80

140–320

ND

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Table 9.4 Reference intervals found in the SENIORLABOR study Analyte

Unit

Reference intervals recommended for routine

Reference intervals found in the present study

Interpretation

Cholesterol

mg/dl

5.2–6.2

3.4–8.1

Slightly higher levels allowed

Bilirubin

μmol/l

50%, and ferritin RI exhibit a general specific behavior: whereas age-independent RI can be employed for male seniors, age stratification of RI is obvious for females. We propose a ferritin reference interval of 20–280 mg/ml for women. For men aged 60 or older, we propose a ferritin RI of 30–500 mg/ml.

9.8 Glucose Metabolism We estimated the prevalence of presumably unknown impaired glucose metabolism, also referred to as prediabetes (PreD), and unknown type 2 diabetes mellitus (T2DM) among subjectively healthy Swiss senior citizens (Medina Escobar et al. 2019). The

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fasting plasma glucose (FPG) and glycated hemoglobin A1 c (HbA1c) levels were used for screening. We looked at a total of 1362 subjects (613 men and 749 women; age range 60–99 years). Subjects with known T2DM were excluded. The fasting plasma glucose was processed immediately for analysis under standardized preanalytical conditions in a cross-sectional cohort study; plasma glucose levels were measured using the hexokinase procedure, and HbA1c was measured chromatographically and classified using the current American Diabetes Association (ADA) criteria. The crude prevalence of individuals unaware of having prediabetic FPG or HbA1c levels was 64.5% (n = 878). Analogously, unknown T2DM was found in 8.4% (n = 114). Based on HbA1c criteria alone, significantly more subjects with unknown FPG impairment and laboratory T2DM could be identified than with the FPG alone. The prevalence of PreD, as well as of T2DM, increased with age. Laboratory evidence of impaired glucose metabolism and, to a lesser extent, unknown T2DM has a high prevalence among subjectively healthy older Swiss individuals. Laboratory identification of people with unknown out-of-range glucose values and overt diabetic hyperglycemia might improve the prognosis by delaying the emergence of overt disease. Along the whole SENIORLABOR evolution, those involved in communicating with study participants have gone through a learning process on bringing over lab results in apparently healthy seniors. The few off-layer values we found were immediately communicated to the participant and their medic such that a second assay on a subsequent blood sampling was performed for confirmation/disconfirmation. The participant was less frightened if an analysis could be situated into the context of senescence, as is the case with slightly elevated HbA1c or CRP levels now confirmed for a discrete w/v increment in seniors. In the PolSenior study, performed on over 4000 seniors over 65 years old, the IL-6 and CRP levels were higher in aging-related diseases/disabilities and lower in successfully aging individuals, and elevated IL-6 and CRP levels were associated with poorer physical performance and progressing glycation in advanced glycation end products which are held non-enzymatic modifications of proteins or lipids upon physiological exposure to sugars, occasionally accumulating in tissue (Puzianowska-Ku´znicka et al. 2016).

9.9 Reference Intervals Found in the SENIORLABOR Study (Risch et al. 2018) With artificial intelligence, laboratory analyzes constitute one of the more important pillars to feed computers with an ever-increasing diversity of data. Not only medicine good but essential biological topics such as embryogenesis, maturation, and senescence are appealed to and await exploration by an ever-increasing community of biologists, now estimated to add up to 2 million researchers worldwide. The skills likely to be in greater demand include interpersonal, higher-order cognitive, and systems skills—all under scrutiny to be made possible using AI. An extraordinary

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amount of information needs to come together to understand how diseases arise. With quick and inexpensive sequencing, DNA and RNA researchers now explore all the “omes”: genome, the complete set of genes. Transcriptome, the RNA made from the genes. The metabolome: small molecules, such as sugars, fatty acids, and amino acids, involved or generated by cellular processes, and the fluxome: metabolic reactions whose rates can vary under different conditions. These two “omes” have nothing to do with quick and inexpensive sequencing. However, they are highly topical scientific areas in research. The Human Protein Atlas has now arrived to include a highresolution map of the locations of more than 12,000 proteins. Data-driven medicine will be an immeasurable valuable tool for improving and personalizing health care. Enrolling older people with hematological disorders in clinical studies needs to catch up. According to a study presented at the 2017 Annual Meeting of the American Society of Hematology (ASH), this population is underrepresented in blood cancer clinical trials. With only a few patients aged 75 or older enrolled in clinical trials, critical information on the safety and effectiveness of new therapies in this age group needs to be improved. This pertains to medical laboratory assays if age-specific RIs are at stake. The magnitude of the disparity is particularly concerning given that the number of adults aged ≥75 years diagnosed with hematological malignancies is expected to rise as the population ages. Currently, 1 out of 5 patients diagnosed with most blood cancers is aged 75 years and older. Dr. Kanapuru urged clinicians to consider enrolling older patients in clinical trials despite their age. She said it is important for clinicians to evaluate patients’ suitability for enrollment in a clinical trial based on their characteristics and not to exclude them based on age alone (Tuchman et al. 2014). Doctors may hesitate to enroll these older patients because they aren’t sure how they will tolerate investigational medications. This population is also highly heterogeneous. You can have a 75-yearold who is very healthy and another person of the same age who is frail and has a lot of coexisting illnesses. The authors said they want to ensure oncologists are aware of the inconsistencies, so they do not blindly trust liquid biopsy results (Rothenberg and Johnson 2017; Borysowski et al. 2021). In pediatrics, age groups reference intervals change within relatively short periods from newborns to toddlers, to child age, puberty, and adolescence. Their computation is tedious because healthy youngsters are not easy to bleed, and one needs parental consent. Analytes like CRP < 10 mg/l up to 10 days of age, thereafter 5 pharmacologically active substances (polypharmacy), and hospitalization during the past 4 weeks.

9.10 The Complement System Part of the innate immune system, complement is a multifactorial protein and cell receptor network of enormous pathophysiological impact but is still neglected in clinical workouts (Fig. 9.8). If you look at Fig. 9.8 attentively (right-hand entries with activation, recognition, and effector pathways), then you see the genius creation of nature, i.e., the interaction of what happens in the fluid phase (blood plasma, synovial fluid, mucosal slime layers, among others) and cells. These carry receptors and structures that recognize specifically the cognate ligand. But this is not the whole story: once the ligand binds to its receptor, ideally with high affinity, the cell fires effector functions explicitly expressed for that given cell type. The literature is scarce about the senescence of these interactions, which is why we mention the complement system (C system), endowed with go (factor B, C3, C4, C1, factors C5–C9) and stop (C1 inhibitor, factor H, factor I) proteins, at the end of our book. Complement, heatlabile on the lab bench, was discovered 100 years ago in the Institut Pasteur, Paris (France) and immediately confirmed to exist at the Robert Koch Institute and has been a topic to raise interest among many researchers. The 18th European Meeting 2022 on Complement in Human Diseases was held in Berne, Switzerland (www.emc hd2022.com). The effector impact of complement is the lysis of cells—complement as predator. Adjunct functionalities of complement are opsonization and cell lysis/ removal of senescent cells. The more than 30 different plasma proteins are mainly in control of inflammatory reactions. They maintain homeostasis and remove immune complexes (waste deposal hypothesis). Three cascades, the classical pathway, the MB-lectin pathway, and the alternative one, are entries into activation. According to the type of pathogen and further factors, the best cascade gets activated. The three cascades lead to the activation of C3 and assembly of the membrane attack complex, MAC. Complement is involved in a series of different diseases. Typically, complement deficiencies lead to infectious problems, such as deficient MAC for Neisseria infections. Systemic Lupus patients are permanently exposed to immune complexes because they lack C2 or C4 or C3 (Ballanti et al. 2013; Macedo and Isaac 2016). These deficiencies turn the equilibrium between induction and prevention of inflammation upside down. When U. Nydegger retired from his hospital job years ago, his office was close to the ophthalmologist outpatient ward, and there were ostentatious numbers of senior people attending the ward. This came from a sudden interest of ophthalmologists colleagues in the C system, their outpatients suffering from vision loss. Thus, age-related macular degeneration (AMD) was first attributed to a dysfunction

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Fig. 9.8 Complement system with its cell receptors. The upper part of the figure depicts the entry sites with the protein designation of the classical and alternate pathways. The lower part shows the cell surface receptors for the cognate ligands, which, after binding, will transmit the signal to the cell interior (namely nucleus and mitochondria), instructing the cell what to do

of CFH (complement factor H), but it is more complicated, the whole C system being involved. GWAS (see glossary) has shown that C has a decisive role in AMD indeed and that patients affected feature an array of risk variants, like mutations of factor H, C2, factor B, and/or C3 (Armento et al. 2021). The first single nucleotide polymorphism (SNP) is SNP rs1061170 for CFH. Other polymorphisms, such as ARMS2/HTRA1, are variant alleles. Whether these nucleotide polymorphisms represent future therapeutic targets is currently the subject of intensive research. Of course, eculizumab, a monoclonal antibody most efficient in hemolytic nephrotic syndrome, binds to the complement protein C5 with high affinity, thereby inhibiting its cleavage to C5a and C5b and preventing the generation of the terminal complement complex, and C5b-9 was immediately studied for efficacy. The pharmaceutical industry, like Pfizer Ophthalmics, never stops reporting advances in the field. For the time being, we authors, U. Nydegger and Th. Lung can only speculate and have done so whether COVID-19, striking the elderly more severely than the workforce population, also originates, at least in part, from a dysbalance of the complement system with hereditary genetic defects allowing for an overshoot of airway inflammation (Lung et al. 2021b).

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References Alpert A, Pickman Y, Leipold M, Rosenberg-Hasson Y, Ji X, Gaujoux R et al (2019) A clinically meaningful metric of immune age derived from high-dimensional longitudinal monitoring. Nat Med 25(3):487–495 Armento A, Ueffing M, Clark SJ (2021) The complement system in age-related macular degeneration. Cell Mol Life Sci 78(10):4487–4505 Ballanti E, Perricone C, Greco E, Ballanti M, Di Muzio G, Chimenti MS et al (2013) Complement and autoimmunity. Immunol Res 56(2–3):477–491 Borysowski J, Lewis ACF, Górski A (2021) Conflicts of interest in oncology expanded access studies. Int J Cancer 149(10):1809–1816 Cozzi A, Santambrogio P, Privitera D, Broccoli V, Rotundo LI, Garavaglia B, et al (2013) Human L-ferritin deficiency is characterized by idiopathic generalized seizures and atypical restless leg syndrome. J Exp Med.210(9):1779–1791. https://doi.org/10.1084/jem.20130315 Hermann W, Risch L, Grebhardt C, Nydegger UE, Sakem B, Imperiali M et al (2020) Reference intervals for platelet counts in the elderly: results from the prospective SENIORLAB study. J Clin Med 9(9):2856 Hordyjewska A, Popiołek Ł, Kocot J (2014) The many “faces” of copper in medicine and treatment. Biometals Int J Role Met Ions Biol Biochem Med. 27(4):611–621 Kraemer R, Schöni MH (2005) Berner Datenbuch Pädiatrie. 951 p. Levine ME (2013) Modeling the rate of senescence: can estimated biological age predict mortality more accurately than chronological age? Journals Gerontol Ser A Biomed Sci Med Sci. 68(6):667–674 López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G (2013) The hallmarks of aging. Cell 153(6):1194–1217 Lung T, Di Cesare P, Risch L, Nydegger U, Risch M (2021a) Elementary laboratory assays as biomarkers of ageing: support for treatment of COVID-19? Gerontology 67(5):503–516. https:/ /www.karger.com/DOI/10.1159/000517659 Lung T, Sakem B, Risch M, Nydegger U (2021b) Convalescent blood plasma (CBP) donated by recovered COVID-19 patients—A comment. Transfus Apher Sci off J World Apher Assoc off J Eur Soc Haemapheresis 60(3):103108 Macedo ACL, Isaac L (2016) Systemic lupus erythematosus and deficiencies of early components of the complement classical pathway. Front Immunol 7:55 Medina Escobar P, Sakem B, Risch L, Risch M, Grebhardt C, Nydegger UE et al (2019) Glycaemic patterns in healthy elderly individuals and in those with impaired glucose metabolism— Exploring the relationship with nonglycaemic variables. Swiss Med Wkly 149:w20163 Miller WG, Horowitz GL, Ceriotti F, Fleming JK, Greenberg N, Katayev A et al (2016) Reference intervals: strengths, weaknesses, and challenges. Clin Chem 62(7):916–923 Mitchell E, Spencer Chapman M, Williams N, Dawson KJ, Mende N, Calderbank EF et al (2022) Clonal dynamics of haematopoiesis across the human lifespan. Nature. 606(7913):343–350. https://doi.org/10.1038/s41586-022-04786-y Mitnitski A, Howlett SE, Rockwood K (2017) Heterogeneity of human aging and its assessment. J Gerontol Ser A Biomed Sci Med Sci. 72(7):877–884 Mitnitski A, Rockwood K (2019) The problem of integrating of biological and clinical markers of aging. Biomark Hum Aging 399–415 Puzianowska-Ku´znicka M, Owczarz M, Wieczorowska-Tobis K, Nadrowski P, Chudek J, Slusarczyk P et al (2016) Interleukin-6 and C-reactive protein, successful aging, and mortality: the PolSenior study. Immun Ageing. 13:21 Rezwan FI, Imboden M, Amaral AFS, Wielscher M, Jeong A, Triebner K et al (2020) Association of adult lung function with accelerated biological aging. Aging (albany NY). 12(1):518 Risch M, Sakem B, Risch L, Nydegger UE (2018) The SENIORLAB study in the quest for healthy elderly patients. 42(4):109–120. https://doi.org/10.1515/labmed-2018-0034

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Rothenberg ML, Johnson DH (2017) Conflict of interest, conflicting interests, and effective collaboration between academia and industry on preclinical and clinical cancer research. JAMA Oncol 3(12):1621–1622 Roy A, Kumar A (2022) Supraphysiological activation of TAK1 promotes skeletal muscle growth and mitigates neurogenic atrophy. Nat Commun 13(1):2201. https://doi.org/10.1038/s41467022-29752-0 Sebastiani P, Thyagarajan B, Sun F, Schupf N, Newman AB, Montano M et al (2017) Biomarker signatures of aging. Aging Cell 16(2):329–338 Tuchman SA, Shapiro GR, Ershler WB, Badros A, Cohen HJ, Dispenzieri A, et al (2014) Multiple myeloma in the very old: an IASIA conference report, vol 106. Journal of the National Cancer Institute

Chapter 10

Geroprotector

Cupidus Rerum Novarum Orandum est, ut sit mens sana in corpore sano We must thrive to keep a healthy soul in a healthy body Juvenal, Satire 10 (about 60–140 years after JC)

10.1 Technical and Medical Possibilities Geroprotectors are designed to delay the onset of concurrent age-related diseases (multimorbidity) and boost resilience (Fig. 10.1). Using animal models, these drugs can ward off problems of the heart, muscles, immune system, and more. And in 2014, investigators reported the results of the first clinical trial of a geroprotector in people over 65: the drug RAD001 (everolimus, inhibitor of the mTOR pathway) is supposed to do a lot of things (http://agingpharma.org/). There has yet to be a consensus on the definition of frailty, although we agree about its usefulness as a clinical term to interpret med lab test results. Nor are there standardized assessments of frailty. Some describe a person as frail if they show three or more: weakness, slowness, low physical activity levels, self-reported exhaustion, and unintentional weight loss. Accumulation of deficits (including hearing loss, low mood, and dementia) can also build a frailty index. The clinical trials for drugs have become quite severe these times. Since 2004, the European Union (EU) Clinical Trial Directive (EU-CTD) has governed the conduct. It attempts to adapt progress in basic science to standardize rules, none the least to optimize patient protection. Senior patients need protection because they are especially vulnerable and need assistance filling out questionnaire forms. Each EU member state has had to implement legal requirements; effective 2022—a new regulation simplifies and harmonizes clinical trials binding all EU member states in its entirety—geroprotectors most probably included. Because several common mechanisms underpin age-related diseases, such as diabetes mellitus type 2, Parkinson’s disease, and Alzheimer, animal models must focus on these. A review of several hundred studies of people and animal models indicates that similar mechanisms underlie several conditions; these can involve DNA damage, © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_10

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Fig. 10.1 Drugs in development for potential antiaging effect. Many clinical studies in seniors include the neologism “geroprotector” which has been used for a decade. The pharmaceutical industry is bound to retard senescence. There are drugs (for example, metformin) used for chronic diseases which wait for their repurposing to geroprotection

such as that caused by free radicals; cellular senescence (in which cells stop dividing and start secreting inflammatory factors); or inflammation and autophagy (the degradation of organelles, misfolded proteins). This may explain why people over 65 are at a higher risk than younger people of developing more than one disease simultaneously. In the United States of America, 7 out of 10 people over 65 with diabetes will die of heart disease, for instance. It is also becoming apparent that one age-related disease can accelerate the onset of others. Elderly, individuals suffering from diabetes mellitus are more than twice as likely to become multimorbid over a short period from overt diabetes (e.g., glycosuria, heart disease) (Sanz-Cánovas et al. 2022). Also, around one-quarter and half of the people over the age of 80 become frail. The accumulation of deficits makes it harder for them to recover from an infection, fall, or other stressors. It remains unclear, though, whether multimorbidity leads to frailty or vice versa or whether they are not connected. Until now, aging research has focused mainly on single diseases or on delaying death. This means that the fundamental mechanisms of aging should be addressed as targets for treating or preventing several age-related conditions. Moreover, patients with multimorbidity are exposed to many drugs at once, often with undesired effects.

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10.2 Agree on Desired Metrics Assessing geroprotectors in preclinical trials and in the clinic requires pharmaceutical investigators to establish attributes to measure efficacy in model organisms and patients. Thus, drugs’ effects on frailty will enable the design of clinical trials that are short and cost-effective. For example, measuring a person’s ability to walk for 400 m is preferable to measuring muscle mass because it improves their ability to live independently. Researchers should then identify the best correlates for these measurements in their study of organisms. From the multitude of routine medical laboratory assays, a potentially meaningful set of assays needs to be assembled to reflect senile sarcopenia best or define risk factors for amyotrophia in paralyzed younger individuals. Ill-known to good medical care, such myocyte-related analytes as calpain, C-terminal agrin, 3-methylhistidine, or cathepsin L genotype on FoxO3, the extent of DNA methylation and mitochondrial health may qualify; these compounds are far from allowing quantitative estimation of sarcopenia, and they have not been included on the test list of neither DO-HEALTH nor SENIORLABOR studies performed with healthy elderly individuals. Current efforts on diagnosing age-related sarcopenia are limited mainly to routine medical clinical parameters such as dual Energy X-ray Absorptiometry (DEXA) or bioimpedance and functional tests such as gait speed and grip strength. However, to motivate drug development in the treatment of the now International Classification of Diseases (ICD)—classified sarcoidosis, novel diagnostic tools that quantitate remaining muscular and functional capacity, including its metabolic rate at rest, are needed. In a model adjusted for sex, age, treatment, and complications, surrogate-marker myoglobin above 60 µg/L may represent a hazard ratio (HR) of 2 for bedridden status; an even lower myoglobin serum concentration of 50 µg/L may become associated with an increase in mortality odds (numbers are estimates). Warm-blooded marmots, bears, squirrels, lemurs, chipmunks, mice, groundhogs, or even turtles and lizards, knowing how to preserve their muscles while hibernating, wake up in spring with all of their muscles as they went sleep. Mostly, these animals metabolize stored nutrients, fat being the longest perduring component. Biomarkers of sarcopenia need to include basic metabolic measures, e.g., lipoproteins, cholesterol, glycemia, hemoglobin, myoglobin, cortisol, and lactic dehydrogenase. Various tools provide a starting point for monitoring resilience in frail elderly people. These include qualitative assessments obtained by asking individuals about their fatigue, pain, and weight loss or tests that monitor mobility, such as gait speed or how long it takes to stand up and walk a certain distance. Regulatory authorities are especially likely to accept “improvement in mobility” as a target. Mobility/fear of falling are good predictors of disability, time spent in hospital, mortality, and healthcare expenditure.

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10.3 Immediate Action Proof-of-concept clinical studies could demonstrate the value of geroprotectors as boosters of resilience in frail patients within the next decade. We ask industry, academic scientists, and regulatory bodies, such as the Federal Drug Agency of the US and the European Medical Agency, to work together in pursuing preclinical testing and clinical trials in frail patients with conditions such as chronic obstructive pulmonary disease, hip fractures, and cancer immediately—even before standardized definitions of frailty and multimorbidity are thrashed out. Many factors have stopped discoveries about geroprotectors from changing patients’ lives. These include the need for many stakeholders to work together, the industry’s tendency to focus on the short term, and the way researchers’ performance is evaluated (the number of papers published carries more weight than time spent helping the community establish definitions, for instance). With an ever-increasing aging population and many nations’ social and healthcare systems close to crisis point, we must take a different approach. The pharmaceutical industry nowadays is busy developing efficient geroprotectors, i.e., drugs that delay aging. And additional biotechnological techniques raise hope that geroprotectors keep abreast of the already established senile organism. Even deep knowledge precedes efficacious geroprotection by, say, 20 years from now. We see biotechnology becoming a game changer in the current drug armamentarium, such as ginkgo derivatives, poly vitamin preparations to cope with skin folds, and wrinkles to fight with retinol-containing creams. It is said that the US actress Sarah Jessica Parker (*1965) refutes wrinkle counter devices because she wants to let go of aging. Numerous clinics offer rejuvenation treatments—their main compound is hyaluronic acid, and they use it for skin rejuvenation, body sculpturing, and other compounds—the phantasy knows no limits—to teeth grinding. The coordination between growth and regression is associated with the availability of selected nutrients. The mechanistic target of the rapamycin (mTOR) pathway is the major nutrientsensitive regulator of growth in animals and plays a central role in physiology and the aging process. As part of distinct complexes, TORC1 and mTORC2, mTOR is the central regulator of mass accumulation and is the crucial link between the availability of nutrients in the environment and the control of anabolic and catabolic processes. The mTOR pathway integrates environmental cues, such as growth factor signals and nutritional status, to direct cell growth of eukaryotic cells and, as we know with increased conviction, aging cells (Lung et al. 2021). Mapping the mTOR signaling landscape has revealed that mTOR controls biomass accumulation and metabolism by modulating key cellular processes, including protein synthesis and autophagy. Given the pathway’s central role in maintaining cellular and physiological homeostasis, dysregulation of mTOR signaling has been implicated in metabolic disorders, neurodegeneration, cancer, and aging. In a recently published review, Blagosklonny highlighted recent advances in understanding the complex regulation of the mTOR pathway. He discussed its function in physiology, human disease, and pharmacological intervention (Blagosklonny 2019).

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Nutrients signal to mTORC1 through the lysosome-associated Rag GTPases and their regulators and associated cytosolic and lysosomal nutrient sensors. In cancer and epilepsy, mTOR signaling is deregulated and, as we now know, in senescence. There is excitement around using mTORC1 inhibitors to treat cancer and neurological disease and, potentially, to improve healthspan and lifespan (Sabatini 2017). Simply extending lifespan is not enough. We need measures and treatments that boost resilience to multiple age-related diseases, ensuring a minimum of impending frailty. The LIFEEXTENSIONR (“stay healthy, live better”) company maintains a Lab Testing Service with close to 200 entries that try to quantitate the senescing process and treat it accordingly. They offer a row of biochemical compounds, like Zinc Caps, Vitamin D3, and N-acetyl-l-Cysteine, and ascribe them a more than an uncertain effect on a long and healthy life. Dasatinib is administered to older mice, young plasma transfer/pheresis, and thymic regeneration GDF-11 restoration; dasatinib is a senolytic drug. Attention has also been given to repurposing approved drugs to treat age-related diseases. Upon this writing, the 9th Aging Research and Drug Discovery Meeting is scheduled in Denmark. (http://agingpharma.org). However, less consideration has been given to natural bioactive compounds. Autophagy, i.e., the organism removing older cells, is a fundamental biological pathway linked to aging, and numerous strategies to enhance autophagy have been shown in animal experiments to extend lifespan. Several natural products are reported to modulate autophagy. Among these are Urolithin A, Spermidine, Resveratrol (contained in red wine), Fatty Acids and Phospholipids, Trehalose, and Lithium (Fig. 10.2). Let us conclude with the idea of the French médecin, Benoit Lesage (*1963), teaching us about corporal posture. He tells us that human posture (Chap. 6) is all there is. U. Nydegger measures 6 feet and 6 inches, and his mother kept saying, “Urs, keep upright”! Dr. méd. Lesage teaches us; posture is an activity, not a condition (Fig. 10.3).

Fig. 10.2 Resveratrol’s simple formula. Resveratrol is a stilbenoid, a natural phenol contained in red wine, and a phytoalexin produced by several plants in response to injury or when the plant is under attack by pathogens such as bacteria or fungi. Sources of resveratrol in food include the skin of grapes, blueberries, raspberries, mulberries, and peanuts

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Fig. 10.3 Posture takes us away from looking old. This sketch shows an older man sitting at a table, once on the left, upright in perfect posture, well dressed and well groomed, soigné. The same person sitting on the right shows him bent over and slumped over. The same person gives the impression of being older and frailer. The posture of us humans decides our degree of senescence as judged by an observer. Tu ne cede malis (senectute !), sed contra audentior ito (Vergil, Aeneis V > I, 95). (Drawn by www.bilderkram.ch)

References Blagosklonny MV (2019) Rapamycin for longevity: opinion article. Aging (albany NY) 11(19):8048 Lung T, Di Cesare P, Risch L, Nydegger U, Risch M (2021) Elementary laboratory assays as biomarkers of ageing: support for treatment of COVID-19? Gerontology 67(5):503–516. https:/ /www.karger.com/DOI/10.1159/000517659 Sabatini DM (2017) Twenty-five years of mTOR: uncovering the link from nutrients to growth. Proc Natl Acad Sci U S A 114(45):11818–11825 Sanz-Cánovas J, López-Sampalo A, Cobos-Palacios L, Ricci M, Hernández-Negrín H, ManceboSevilla JJ et al (2022) Management of type 2 diabetes mellitus in elderly patients with frailty and/or sarcopenia. Int J Environ Res Public Health 19(14):8677

Chapter 11

Hannibal Ante Portas

Cupidus Rerum Novarum Misce stultitiam consiliis breve Annex some folly to wisdom Horace, ode 12 of book IV

11.1 Hopeful or Dangerous Future What about when the slowing of senescence and rejuvenation becomes true? In the 2nd Punic war, the population of ancient Rome was afraid when the Carthaginian commander Hannibal and his warriors arrived on the outskirts of Rome, ante portas:—at the doors. We invite the reader of this book to imagine the announcement of a horrifying future in which a fraction of humanity with bad faith would exist for prolonged periods. Habent sua fata libelli , (books have their destiny).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1_11

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Senescence—Back and Forth Authors Urs Nydegger, MD and Dr. rer. nat. Thomas Lung A quibus ergo accipiemus Who will give us Seneca, De Beneficiis (II–XVIII) Ageing Clock cfDNA DALY Delayer Dementia DNA, or deoxyribonucleic acid

Escaper GWAS Geroprotector HPLC

Immunosenescence Juvenescence

Extent of DNA methylation Cell free DNA, quite abundant Disability-adjusted life years Somebody between 80 and 100 years of age Lost cognition Hereditary material in plants, animals and humans. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus and completed by protein in the chromosomes, a completion which we call chromatin A centenarian Genome wide association study: which gene associated to which disease Drugs to delay senescence, biological ageing retarded High-power liquid chromatography, a technique to be used to separate different chemicals from each other Biological aging of the humoral and cellular immunity Turning towards youth, so far a speculation

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 U. Nydegger and T. Lung, Senescence Back and Forth, https://doi.org/10.1007/978-3-031-32276-1

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LINE MALDI TOF

mDNA or DNAm Methylation Mitophagy NAD Opsonisation Phagocytosis Predementia Rapamycine Reference Interval SASP Senescence Senolytics Stem cell Stem cell engraftment

Survivor TOR

Glossary

Long Interspersed Nuclear element (retrotransposons) Abbreviation for Matrix-assisted laser desorption/ionization time of flight. This is a sensitive procedure to identify and quantitate biologics Methylated DNA Decoration (of DNA) with—CH3 Degradation of mitochondria by autophagy Nicotine amide dinucleotide, involved in DNA repair To cover, overlay cells and surfaces with proteins preparing them for phagocytosis To ingest, e.g. cells incorporating opsonised material, e.g. microbes Towards loss of cognition Repurposed drug (Sirolimus) for humans used to rejuvenate mice Range of normal med lab assays Senescence-associated secretory phenotype Biological aging—different from chronological ageing Drugs that remove senescent cells Origin of differentiated cells; target of rejuvenation Transplanted stem cells travel from blood to the bone marrow, where they begin to make new white blood cells Somebody who turns 80 years of age Targets of rapamycine, structures on cell surfaces binding rapamycine