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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Elasticity is absolutely necessary for living a normal life. This fact is cruelly revealed when respiratory, cardiac, digestive, sensory, motor, reproductive or aesthetic problems appear following the inexorable decline of our elastic capital. The protection and maintenance of this capital is one of life's priorities since this declination begins at the age of twenty and accelerates in times of crises and pandemics. However, there are no therapies yet designed to remedy it. The first part of the book explains the consequences surrounding a lack of elasticity in the skin, the most visible decline, and then other defects in elasticity throughout our bodies, exploring places rarely mentioned. The second part describes the research fighting against elasticity anomalies and examines useful behaviors to protect our elastic capital (e.g. our diets and physical and cognitive activities). This last point is at the heart of current social debates on nutritional, behavioral, environmental and even ethical levels.
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Table of Contents
Cover
Table of Contents
Title Page
Copyright Page
Foreword
Preface
Acknowledgments
Introduction
PART 1: Fantastic Elastic Capital
1 Strengths and Weaknesses of the Elastic Human
1.1. Introduction
1.2. Longevity and elasticity
1.3. Disasters
1.4. Cutaneous elastic capital
1.5. Loose skin and cutis laxa
1.6. What is missing and malfunctioning in these fiber diseases?
1.7. What structures and strengthens the elastic system
2 Elastic Capital, Air, Water and Other Fluids
2.1. Introduction
2.2. Respiration
2.3. The 12/8 of perfect blood pressure!
2.4. Cellular respiration and energy
2.5. The logistics of digestion
2.6. Vascular dilation and constriction
2.7. Sugar logistics
2.8. The perineal set and terminal delivery logistics
2.9. The microbiota and its body bioreactor
2.10. Conclusion
3 Elasticity and the Senses
3.1. Introduction
3.2. Singing and dancing
3.3. Light transmission and elasticity
3.4. Auditory transmission and elasticity
3.5. Olfaction
3.6. Taste
3.7. Touch and proprioception
3.8. Elasticity and the peripheral nervous system
PART 2: The Four Challenges of the Elastic Human
4 The First Challenge for the Elastic Human
4.1. Introduction
4.2. Stress of elastic structures
4.3. Stresses on organs and fluids
4.4. Genetic stress
4.5. Stress and epigenetics
4.6. Pharmacology and stress
5 The Second Challenge for the Elastic Human
5.1. Introduction
5.2. Elastic capital and phytotherapy
5.3. Elastic capital and dill
5.4. Epigenetics and marjoram
5.5. Adopting a plant
5.6. Elastic capital and protein restriction
5.7. Elastic capital and a reasoned diet
5.8. Glycine on the menu
5.9. Elastic capital and an unreasonable diet
5.10. Elastic capital and pollution
6 The Third Challenge for the Elastic Human
6.1. Introduction
6.2. The alchemy of movement
6.3. Elasticity at both ends of life
6.4. The reference frames of motion
6.5. Flattering the view and looking good
6.6. Feeling your proprioception to improve your posture
6.7. Touching and stroking to promote elasticity
6.8. Hearing and feeling in order to enjoy the song and movement
6.9. Conclusion: let us adopt a loop of “pro-elastic” postures
7 The Fourth Challenge for the Elastic Human
7.1. Introduction
7.2. Cross-linking and knowledge
7.3. Resilience and the mechanics of the world
7.4. Compliance, ethics, law and elastic capital
7.5. Chapter summary
Conclusion
Appendix
A.1. Introduction to elasticity modeling by Professor Yves Rémond
A.2. Introduction to the actors of the elasticity of life
A.3. Elasticity and the structures of the body
A.4. Elasticity and the circulation of fluids and gases
A.5. Motor and autonomous sensory receptors
A.6. Pathologies due to a deficiency of the elastic system
A.7. Aging and elastic fibers
A.8. Elasticity and its maintenance
A.9. Elasticity and movement
A.10. The laws of breathing and yoga
A.11. Epigenetic regulation
A.12. Elasticity and bioengineering
References
Pascal Sommer’s bibliography
Index
Other titles from iSTE in Health Engineering and Society
End User License Agreement
List of Illustrations
Introduction
Figure I.1.
The disasters of the elastic human. The intention of this first
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Chapter 1
Figure 1.1.
Structures and fluids of the elastic human. The intention of thi
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Figure 1.2.
Stress transmission in the skin. The diagram illustrates the lev
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Figure 1.3.
Elastic fiber assembly process. The formation of elastic fibers
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Figure 1.4.
Positioning of organs and tissues according to their Young’s mod
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Chapter 2
Figure 2.1.
“The Big Breath”. The third painting pays homage to the necessit
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Figure 2.2.
The elasticity of the body and the breathing cycle
Figure 2.3.
The cardiovascular elastic system
Figure 2.4.
The ATP formation cycle
Chapter 3
Figure 3.1.
The sensory bullfight. This fourth painting illustrates the abun
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Figure 3.2.
The elasticity that is essential to the hearing, vision and olfa
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Chapter 4
Figure 4.1.
Repairing the elastic human. The fifth painting integrates the h
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Figure 4.2.
Pathologies and syndromes of elastogenesis imperfecta. The figur
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Chapter 5
Figure 5.1.
Working hypothesis mechanism of LOXL1 gene promoter regulation d
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Figure 5.2.
Impairment of the elasticity of the pulmonary alveoli
Chapter 6
Figure 6.1.
The elasticity of movement. Elasticity is ubiquitous in movement
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Chapter 7
Figure 7.1.
Elastic capital and otherness. The intention of the sixth painti
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Figure 7.2.
The elastic human’s mind. The intention of the seventh painting
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Guide
Cover Page
Title Page
Copyright Page
Foreword
Preface
Acknowledgments
Introduction
Table of Contents
Begin Reading
Conclusion
Appendix
References
Index
Other titles from iSTE in Health Engineering and Society
Wiley End User License Agreement
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Series EditorJean-Charles Pomerol
The Elasticity of Life
From Tissues to Humans
Pascal SommerRomain Debret
First published 2023 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd
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www.iste.co.uk
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© ISTE Ltd 2023The rights of Pascal Sommer and Romain Debret to be identified as the authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.
Library of Congress Control Number: 2023935278
British Library Cataloguing-in-Publication DataA CIP record for this book is available from the British LibraryISBN 978-1-78630-907-5
Foreword
After years of working together, Pascal Sommer and I organized a scientific conference in French at the headquarters of the Centre National de la Recherche Scientifique (CNRS) in Paris entitled “Repairing the Elastic Human: From the Fundamental Sciences to the Surgery Room”. Pascal Sommer as a biologist researcher, a recognized specialist in tissue elasticity among others, and I as a mechanic of materials and biomaterials, and specialist in engineering sciences, had prepared this event within the framework of our responsibilities at the CNRS. The title of this conference was surprising for many and did not fail to attract attention. It was a success. Scientists of great talent explained the progress of knowledge on the subject and especially the stakes of this elastic human, the heart of Pascal Sommer’s essay that I have the honor and the pleasure to comment on here. Questions were flying around: what could be the role of elasticity in the human body?
A few days later, we were guests of Fabienne Chauvière, journalist and producer of the program “Les Savanturiers” on France Inter, dedicated to scientific advances. The participation in radio programs, without being exceptional, was not something we did regularly. So, as soon as the program began, the journalist asked me point-blank if the title of our conference was not a bit provocative. Surprised by this incisive start, I gave a general and, it must be said, conventional answer, a little bewildered by the question. Pascal Sommer then took the floor and answered Fabienne Chauvière that without elasticity, she would not be alive, her heart would not beat, her lungs would not function and allow her to breathe, her blood would not flow for long in her arteries, and the movements of her body would be so impossible that her skin would crack and age would weaken the functionality in all parts of the body. The surprise was reversed, and the program got off to a good start. I think it was this answer, which lasted less than a minute, that showed me in a concentrated way how vital the elasticity of the human body was. The symposium had shown that the observation of this elasticity was now so well advanced and well documented that its role was taken very seriously, but its determinants were only imperfectly known. It was necessary to understand them at all human scales, from that of DNA or proteins to the macroscopic scale of tissues, passing through the scales of the various cellular or tissue components. But let us return to the mechanical description of elasticity, since I have the honor to introduce this concept in this book at the request of Pascal Sommer.
That elasticity is a property of inert matter has been known since the dawn of time. It was only conceptualized in the middle of the 17th century, because of a great English scientist named Robert Hooke. Then, the engineers and scientists who followed continued his study, and their results are the basis of all designs of objects, machines, buildings or vehicles that surround us. Its extension to the observation of the living is however much more recent. It is striking to see that this scientist who studied at Oxford, to whom we owe also the first acoustic telephone, had synthesized the elastic law of bodies by a sentence that has become famous: Ut tensio sic vis (elongation is proportional to the force). It is also interesting to note that Robert Hooke was also a pioneer in biology. We also owe him the word “cell” for living plant cells, which he was already observing under the microscope!
Today, elasticity is well understood and modeled in the mechanical domain. We distinguish different forms that all have in common the state of stress being linked to a material’s state of strain at a point in space. We agree that these laws are very useful because they allow us to model, for example, the point of failure of an aircraft wing or the reactor vessel of a nuclear power plant. When mechanical behaviors are linear, with simple and unstructured materials, this elasticity is described by a law (called “Hooke’s law”) whose mathematical formulation is introduced in section A.1 in the Appendix. This organization is called isotropy when the mechanical properties of a segment are independent of the organization of the whole (this point is under discussion for characterizing the behavior of the universe).
And in the case of living tissue, you may ask? We have no precise information. It is obvious that biological media are rarely organized in a uniform way and that they all have an elasticity. The formulation of this elasticity, even if reduced, is very complex. In physical language, we qualify as anisotropic their organization, when organizational directions are imposed as in a venous wall or a bone. It is then necessary to have more mechanical constants to characterize and model them mathematically. Especially in warm-blooded animals whose elasticity may depend on temperature, which may require additional consideration for the laws of thermodynamics. It is likely, as with some elastic polymers, that we are in the presence of a mixture of several types of elasticity, but the question remains open and will probably depend on the scale at which we will place ourselves.
Finally, let us also recall that the material offers us interesting variants of elasticity:
First, viscoelasticity, which introduces delays in the elastic reaction of solicited matter. This is typically the case for living matter, where viscosities are at work at all scales. We can measure viscosity maps as well as stiffness maps of living tissues and derive useful clinical information from them. We are interested in this for muscular tissues with regard to Duchêne’s disease, for example, or for the rigidity of tumors. The injection of hyaluronic acid in the joints responds to this need to locally increase viscoelasticity.
We could also talk about super-elasticity, which is typical of certain artificial materials used in the human body for their ability to have a shape memory. It is used for example to manufacture stents or surgical wire, which will be discussed in this book. This particular elasticity comes from a phase change of the material during solicitation. This phenomenon is then used to store particular strains and restore them, thus activating a memory effect. The most classical inert materials in this field are the Nickel–Titanium alloys found in some prostheses.
Finally, we mention the hyper-elasticity concept that has allowed us to understand and model the elastic behavior of many media and in particular biological media. The skin is an example. In this case, we use the data of a thermodynamic potential like the free energy from which a law of behavior is derived to characterize them.
This brief review of elasticity allows us to show that the elasticity of living tissues is part of a great history of solid and fluid mechanics, which started in the middle of the 17th century. It has expanded sufficiently to take into account many complex phenomena, including now the phenomena described by biology. It is in this context that Pascal Sommer’s book is written, whose expertise in biological, human and social sciences perfectly illustrates the great diversity, but also the great complexity, that must be added to physics in order to deal with it.
Today, the developments of the elasticity of living organisms find a particularly fertile field of application in mechanobiology. The aim is to observe and then try to understand the effect of mechanics on biology. For example, we can thus direct the development of a stem cell or tumor cell by playing on the elasticity of the medium on which it is placed. This type of phenomenon, which is not yet fully understood, illustrates this surprising relationship. In another field, we can also see how the cells that are at the basis of bone remodeling and scarring are strongly influenced by gravity. An unfortunate consequence is the bone loss that many astronauts undergo during space flights in microgravity. This phenomenon, which has been studied extensively and is equivalent to osteoporosis, is not completely understood either.
We could multiply the examples over and over again; the field of action of the elasticity of living things is immense, and we are still far from having acquired the understanding and the knowledge of these numerous phenomena. Reading Pascal Sommer’s book on this “elastic system”, which has never been exposed at this level, will easily give readers the measure of the immensity of the biological phenomena associated with elastic behavior and their importance in our life. I am convinced that the next few years will be crucial for the knowledge in this field and that we will obtain new and useful results for humanity. Enjoy reading this book!
Yves RÉMOND
Université de Strasbourg
Preface
This book covers the elasticity of living things, from tissues to humans. It is a subject generally approached from a functional angle when the body becomes insurgent and manifests itself painfully. It is the register of physical limitations when mechanical functions become non-functional or missing. It is a register of morbidity when the lungs, the heart or the kidneys lose their necessary elasticity. It is also a parameter of capacities and feats when our elastic performances are confronted with our limits. The singularity of this elastic capital is being able to evaluate its own inexorable decline linked to age.
We often confine the problem of body elasticity to the appearance of wrinkles that mark our aging. However, everything that moves in the body is involved because elasticity is the means of absorbing the shocks of pressure or extension to quickly return to the normal situation. We need elasticity when we construct, run, sing, read, write, cook, eat, talk, watch, make love or give birth. At any moment, the elastic properties of our body condition our dynamics and our actions, whether it is in terms of bones, tendons, ligaments, fascias and muscles, but also in our lungs, hearts, intestines, kidneys or bladders. Elasticity is also necessary for sensoriality and is part of the register of behaviors; it is mobilized by the senses, sexuality and fertility. Finally, it is the register of the spirit and ethics when the repertoire of our elastic capital sets limits to our actions and societal proposals.
The subject of human elasticity is complex and interdisciplinary, but it is rarely presented in a comprehensive form. It is the intention of this book to position the concept of elasticity of living things at the heart of our lives, which is the reality. After a first part positioning the actors and the problems when elasticity is lacking, the book will address solutions to protect, maintain, reinforce or replace our elastic capital. As elasticity is omnipresent in society, its presentation is necessarily situated at the interfaces of experimental sciences (biology, chemistry, physics, mechanics) and human, social and societal sciences.
May 2023
Acknowledgments
The writing of this book was based on my interdisciplinary experience in the fields of biology and pharmacology of elastic tissues, aging, engineering for health and loss of autonomy. It was developed in response to the injunction of global pandemics, whether viral, dietary, behavioral or societal in origin.
Professor Yves Rémond, a specialist in the mechanics of materials and professor at the Université de Strasbourg, did me the honor of writing the foreword to this book and of contributing his expertise on the science of materials. His skills and enthusiasm have constantly enriched my much more limited knowledge of mechanics.
I thank Romain Debret, researcher at the CNRS, who participated in the work, especially in the appendices. His contribution on the development of drugs and devices is decisive to instruct an epigenetic regulation of altered elastic tissues. In addition, his involvement in patient association programs is exemplary. The 10 scientific figures were developed under his supervision by Anne-Lise Paris (www.in-graphidi.com) in the framework of a research action supported by the French National Research Agency (Agence Nationale de la Recherche, ANR-18-CE18-0001).
Because of her expertise in pharmacology and law, Valérie Siranyan’s contribution was necessary to intelligibly formulate the ethical questions raised by the alteration of our elastic capital. A professor at the Université de Lyon 1, she advised me on the aspects relating more specifically to the human and social sciences. As an editor of books on national and international health regulations, her experience leads her to identify users’ rights as a fundamental element of public health ethics. Her neologism of Handicracy, introduced during the course of this book, illustrates these notions well and was the subject of a joint symposium.
My work on elastic tissues has benefited from multiple resources provided by the CNRS, the universities of Lyon and Marseille and the Institut Pasteur in Lyon. I would like to thank all my past and present colleagues, as well as the French taxpayers and the donors of the Telethon who have contributed to the funding of our research. I would particularly like to thank my colleagues who passed through the Institut Pasteur in Lyon where this story really started, notably Michèle Chevallier, Alexis Desmoulière, Françoise Gérard, Claudine Gleyzal, Jean-Alexis Grimaud, Sylviane Guerret, Hugues Lortat-Jacob, Simone Peyrol, Mireille Raccurt and Sylvie Ricard-Blum.
The studies were carried out at the Institut de Biologie et Chimie des Protéines – CNRS – Université de Lyon, with notably Géraldine Aimond, Aurore Berthier, Romain Debret, Denise Eichenberger, Jean Farjanel, Bernard Font, Bérengère Fromy, David Hulmes, Caroline Reynaud, Dominique Sigaudo-Roussel, Jérôme Sohier and many others.
The work continues in Lyon under the aegis of Romain Debret and Jerome Sohier, as well as at the Institut des Sciences du Mouvement (CNRS – Aix Marseille Université) where I was particularly well received by Martine Pithioux, Patrick Chabrand, Jean-Louis Milan, Virginie Taillebot and Eric Berton, all experts in biomechanics.
Many doctoral students worked hard to give the best of themselves on this subject, and particularly Jérémy Boizot, Agnès Borel, Charbel Bouez, Thierry Brune, Valérie Cenizo, Stéphanie Claus, Leslie Laquièze, Claude Jourdan-Le Saux, Gabrielle Le Provost, Chloé Lorion, Carine Mainzer, Léa Moulin, Emmanuelle Noblesse, Marie Peraldi-Decitre, Floriane Pez, Sophie Sève and Laetitia Thomassin. They did a fantastic job!
Several collaborations have been important but certainly those with Odile Damour and her team at the skin substitute laboratory of the Edouard Herriot Hospital as well as those of Eric Perrier, Valérie André and Isabelle Orly from the company Coletica, now BASF Beauty Care Solutions France, which have offered the use of a unique model of human reconstructed skin.
The history of the cutis laxa owes its imprint to the Boiteux family, the originators of the international cutis laxa association. The anecdotes about the September 12, 2001, broadcast of the program “Ça se discute” organized by Jean-Luc Delarue are real. The constitution of a research consortium, some of whose funds came from the Telethon, was initiated by Christine Bodemer’s team at the dermatology department of the Necker-Enfants Malades Hospital in Paris, then with Anne de Paepe’s team at the Center for Medical Genetics Ghent. The complex notions of ethics of rare diseases were largely explained to me by Marie-Hélène Boucand.
My story on elasticity has been profoundly European, because of several programs financed in part by the European Commission that I contributed to setting up or leading with the participation of Daniela Quaglino at the Università degli Studi di Modena e Reggio Emilia in Modena, Julia Bujan at the University of Alcala de Henarès, Marie-Paule Jacob at the Bichat Hospital – INSERM – Paris, Brigida Bochicchio and Antonio Tamburro at the University of Potenza, Catherine Kielty at the University of Manchester, and Gilles Faury at the Hypoxia and Cardiovascular and Respiratory Pathophysiology Laboratory INSERM – Université de Grenoble.
I also thank Radovan Borojevic at the Federal University of Rio de Janeiro, Doris Germain at the Icahn School of Medicine at Mount Sinai – New York, José-Mauro Granjeiro at the Institute of Metrology of Brazil, Paulo Pinto Joazeiro, Instituto de Biologia, Unicamp – Campinas, Robert Mecham at Washington University – Saint Louis, Ursula Schlötzer-Schrehard at the Universitäts Augen klinikum in Erlangen, Philip Trackman at the Boston University School of Dental Medicine and Hassan Zahouani at the Ecole Centrale de Lyon, as well as Laurent Apert, Marielle Bouschbacher and Christelle Laurensou from the URGO laboratories, Carla Barichello and Noelle Remoué – Sohier from the Natura laboratory in Sao Paulo.
The rich contacts at the CNRS management and the CNRS mission for interdisciplinarity have made it possible to build a story where biological sciences, engineering sciences and human and social sciences converge. I would like to mention for their contribution Olga Allard, Philippe Bompard, Andréï Constantinescu, Luc Darrasse, Marie Gaille, Pierre Guillon, Christophe Jouffrais, Marie-Christine Lafarie-Frenot, Dominique Leguillon, Jean-Yves Marzin, Patrick Netter, Yves Rémond, Anne Renaud and Jean-Louis Vercher.
However, there were so many others like all the leaders of projects supported by the CNRS on the loss of sensoriality and autonomy who exploded the boundaries between sensoriality, movement and body mechanics as well as my colleagues from the Commission de Pharmacologie, Bio-ingénierie, Imagerie, Biotechnologies du Comité National de la Recherche Scientifique (CoNRS) that I had the honor to preside over. I illustrated my remarks on perception and disability with a few words on projects developed on sensory stimulation with Asaf Achraf, Malika Auvray, Pierre Ancet, Jérémy Danna, Leslie Decker, Coline Joufflineau, Agnès Robby-Brami, Fabrice Sarlegna and Jean-Luc Velay, on olfaction with Moustafa Bensafi, Liliane Borel, Jérôme Golebiowski and Norbert Noury, and on tactile perception with Marie-Ange Bueno, Marcel Crest and Betty Semail, on hearing and phonation with Lucie Bailly and Nathalie Henrich, on the control of assistive devices with Stéphane Buffat, Eric Campo, Loic Caroux, Jozina de Graaf, Nathanael Jarrassé, Laura Lemahieu, Noelle Lewis, Caroline Nicol and Nadine Vigouroux and finally on disability with Mai-Anh Ngo and Valérie Siranyan.
Some of my colleagues and friends who collaborated in this story have passed away and I would like to ask for them to be remembered: Stephen Baydanoff in Pleven, Jean-Louis Boiteux, Robert Frank, Léon Hirth, Jean-Paul Klein and Anne-Lise Pini in Strasbourg, Ladislas Robert in Paris, Olivier Toussaint in Namur, Yvonne Pasquale-Ronchetti in Modena and Tony Tamburro in Potenza.
The proofreading, corrections, foreword and discussion benefited from the meticulous work of Marie-Claude Boiteux and Mireille Tessier of the international cutis laxa association as well as Elyane Sommer. Any royalties from this book will be donated to associations involved in research on pathologies affecting elastic tissue.
And of course, I thank my family and friends, who had the patience to support me and read my work during the very long development of this book.
Pascal SOMMER
Introduction
Figure I.1.The disasters of the elastic human. The intention of this first painting is to illustrate the weakness of a body abandoned by its elastic forces. It is inspired by Francisco Goya’s engraving in his work entitled The Disasters of War illustrating the consequences of the invasion of Napoleonic troops in Spain. The painting Gracias à la almorta depicts the effects of the famine and the use of a bread substitute made of sweet pea flour. This plant contains a neurotoxin that can cause paralysis of the lower limbs and another toxin that prevents the proper formation of collagen and elastic fibers, with serious pathological consequences on the skeleton. The term lathyrism derives from the generic name of peas, including some species of Lathyrus. The engraving represents a family of which I have taken only three members with a woman unable to stand up to eat and drink
This book on the elasticity of living things aims to present a global vision of the elasticity of the human body. We could extend a large number of our reflections to all mammals. This vision of the elasticity of living things is omnipresent in art or culture because it is underlying the perfection of the body or its imperfections, innate or acquired with time. The representation of youth with beautiful smooth skin on a toned body, or of old age with craggy skin on weakened silhouettes constantly illustrates this throughout the history of painting. But the consequences of a lack of elasticity are even more strikingly illustrated in the opening figure, which depicts slumped figures, possibly in respiratory distress, unable to stand and begging for help to bring a simple jug of water to their mouths. I have freely used this engraving as a symbol for this book, just as I have used other famous painters to illustrate many parts of this book. Iconography abounds with these unfortunate people whose elasticity is degraded by diseases, infectious or not, capable of affecting many of our organs. So let us take some time and look at the elasticity of our human vehicle, which can be severely damaged by a toxin or a virus, but which is also damaged in a much more insidious way by other modern-day pandemics, linked to deleterious food and behaviors that concern us all.
Science has never been so much a part of our lives, nor has it provided information that can help us understand and manage our fantastic elasticity. The advances in science have undoubtedly reduced the toll of loss of autonomy associated with loss or defects in elasticity. The subject is topical because some of these defects have been seen in the consequences to the coronavirus pandemic since 2019, in the short or long term. This book carries the ambition of sharing knowledge on just about all the elastic capacities of the body that we unconsciously use when everything is going well and that become tyrannical when they are affected, due to simply being essential to life. There are many causes for the disruption of these capacities. The most obvious is related to aging, a universal cause. The loss of elasticity can also be amplified in times of threats and sanitary crises, such as during epidemics or viral, bacterial and parasitic pandemics, which humanity has seen, sees and will see again. We can die from a lack of elasticity, especially when a viral attack induces an exaggerated inflammatory response in the body and alters the mechanics of the respiratory and cardiovascular systems. Constraints are also very strongly imposed on our body mechanics due to the harmful effects of uncontrolled industrialization. They will probably be further amplified by future climate change.
The concept of elasticity of the body remains very vague, even if it imposes itself on our everyday realities, and to take it into account makes it possible to enrich playful or preventive behaviors or to support recommendations and prescriptions in multiple fields. It is our ambition to present it in a form that is accessible and systemic, in a functional and even performative approach. I know from experience, through the many questions I have been asked, that the notion of elasticity is only addressed occasionally and in critical situations. The first part describes the elasticity of the skin, tissues and organs as well as the body’s structure (bones, tendons, ligaments and fascias) in a global manner. We will then move on to the aging and healing of the skin, as well as the calcification and strengthening of the structures that give the body its mechanical capacity. We will examine the difficult situation of children and adults who do not have adequate elastic capital. We will present the essential role of elasticity in the transport of gases, liquids and energy. We will see how this process is affected by respiratory and cardiovascular insufficiency, but also by excess food and drink (alcohol, sugar or meat). We will discuss how the five senses can depend on elasticity, to which we will add the sixth sense of proprioception. Finally, we will see how sexuality and fertility are intimately affected by elasticity.
This first description aims at linking the numerous aspects of human elasticity in a synthetic vision. Once these notions have been introduced, it will be a matter of considering the actions that promote or protect our elastic capital, knowing that these actions are often the result of expert considerations, affecting both our personal behavior and societal choices. It was therefore necessary to develop a vision that is based on both undeniable scientific foundations and strong social and societal representations. The range of this synthetic, interdisciplinary and timeless vision was therefore not obvious, and it is the almost mathematical analysis proposed by Jacques Ellul of an old text that offered me an adequate segmentation (Ellul and Rognon 2008). This is the analysis of the passage describing the four horsemen of the Book of Revelation, which we will consider only from the point of view of dialectical construction. The first horseman is emblematic of the spirit, whatever its substance; he rides a white horse, and he appears first but will really be active last. The second rider gallops on a fire-red stallion and spreads war and stress. The third rider rides a black steed and orchestrates famine. The fourth represents death and the immobility to come on his pale horse. Each of these four figures assumes a mission that can be both destructive and challenging. It is this delineation of four missions that attracted me and led me, by analogy, to orchestrate the presentation of four challenges for the elastic human. The first challenge consists of limiting the stress linked to the loss of elasticity as much as possible. In this book, we will describe the different manifestations of this stress that are often ignored, even by therapists. Advances in medicine and engineering are part of the fight against these stresses. This challenge is therefore a matter for specialists but also for expert patients; the more the former have a systemic view, the better their diagnosis will be; the more educated patients are, the better their dialogue with specialists will be. The second challenge is food, in the broad sense of the word, because it concerns all the inputs which are essential to the elasticity of living organisms, either by protecting and promoting our elastic capital, or by participating in the fight against pollution. It is certainly a matter for experts but also for common sense, in an economy that has lost some of its safeguards that often need to be reframed. The third challenge mobilizes our resources through movement associated with a thoughtful sensoriality, which seems obvious but is not useless to clarify. This need for action and perception is necessary to challenge the after-effects of a sedentary lifestyle or, conversely, the harmful effects of repetitive movements. The preservation of a good elastic capital, coupled with muscular and sensorimotor resources, effectively orchestrates the maintenance of our joint mechanics and ensures the fullness of our autonomy. The fourth challenge is embodied in the consideration of the elasticity of the mind, both individual and collective. It invokes notions of knowledge, culture and ethics that will be outlined in this book under the strict prism of a voluntarily reductive semantics resulting from the laws of mechanics and elasticity. It introduces the consideration of difference, whether innate or acquired, which opens up the subject to social and societal considerations that respect the values of humans with different elastic potentials, by nature or by accident.
Taking into account the elasticity of the body therefore leads us to manage these four challenges, the management of stress, nutrition, movement and morality. These four challenges become all the more important when technologies seek to exceed the archetypal limits of humanity. The intentions of human augmentation are indeed based on the desire to generate a being with a body that is insensitive to stress, fed in an optimized way, fortified because of technologies that induce tissue regeneration or the replacement of disabilities, and with a mind reinforced by artificial intelligence.
The good news is that it is possible to care for what we will call our elastic capital, by correctly assuming the required choices and actions. Indeed, the proper management of elasticity depends a lot on us, both at the individual and societal levels. We will present what medicine and engineering can do for us, and what we can do for ourselves. By reciprocity, we will explore what the notion of the “elastic human” can bring to society in an interdisciplinary approach ranging from the smallest (genes, proteins) to the largest (the individual and society). Each part can be read independently, relying if necessary on summaries and technical details that can be consulted in the appendices.
In order to present concrete cases, we will recurrently present the situation of people with an accelerated loss of their elastic capital, innate or acquired, i.e., of genetic origin or not. The health news related to pandemics also leads us to introduce the case of people who suffer from the loss of elasticity, sometimes lethal and often chronic, of the lungs or other organs.
As this book ultimately embodies a very personal vision of humanity that cannot be without reference to culture and the spirit of the times, I wanted to introduce seven digital paintings created with mixed media, inspired by famous paintings, as manifestations of elastic thinking.
PART 1Fantastic Elastic Capital
1Strengths and Weaknesses of the Elastic Human
1.1. Introduction
The bodies of human beings and animals have been built for and by movement. Those who have been immobilized will surely share my point of view, without denying the amazing faculties of the mind. One can always quibble about the supremacy of the mind over the body, but in reality there is no mind without a heart to feed the brain. A key to this movement is the varying ability of the body’s organs and tissues to return to their original form after deformation. This is what defines elasticity. It is what allows the walls of the lungs and arteries to inflate and deflate according to the rhythms of breathing, or the bladder to fill and empty. Addressing the concept of the “elastic human” is therefore a cause rich in implications, as basic as breathing or managing one’s movements without untimely urinary and digestive interruptions! The loss of elasticity can induce multiple inconveniences ranging from temporary discomfort to chronic painful syndrome or even, at the extreme, to a partial or total loss of autonomy. More specifically, we can mention heart failure, aneurysms, emphysema, wrinkles, intestinal and lymphatic laziness, ligament rupture, herniated discs and inguinal hernias, rheumatoid arthritis, the difficulties of procreation or sensory deficiencies including the loss of vision and hearing. It is a catalog that is still far too rich to date because it concerns a large proportion of current diseases, chronic or not!
The loss of flexibility and elasticity affects all living beings. Indeed, the elasticity of the body is not renewed or renewed only a little after the completion of growth. This observation leads us to follow the inexorably negative evolution of what must be considered a capital, which wears away during aging, in a visible way in terms of the skin, or collapses during crises, as in the lungs of people suffering from respiratory pathologies.
1.2. Longevity and elasticity
We all have an elastic capital that deteriorates more or less rapidly over time. Fortunately, our life expectancy has increased considerably; it has almost doubled, on average, for populations living in the most industrialized societies. The appearance of wrinkles and elasticity defects is therefore more obvious, or at least we will experience them over a much longer period of time. While this progression of wrinkles is an annoying indicator of aging, the loss of elasticity in all or part of the rest of the body can become more disabling. This leads us to dream of a reprogramming that could modulate the slow decline of our elastic capital. It would be a matter of counteracting the vicious circle that sets in when the elasticity of tissues is reduced, more or less slowly, but always inexorably. Like personalized therapy capable of softening and even saving lives, it would be useful in adults and necessary in children and adults affected by genetic mutations causing a malfunction of elastic tissues. Unfortunately, for the time being, medicine and pharmacology still know little about the causes of this loss of elastic capital because no one knows how to reinduce, replace or repair identical tissues that have become too stiff and inextensible. The reprogramming of body tissues once growth has been achieved remains a challenge for caregivers and researchers. Without going as far as supporting the concept of transhumanism whose objective is to push back the temporal limits of life or to maintain eternal youth, the wish to be able to claim an optimized management of our elastic capital becomes universal.
1.3. Disasters
It is sometimes difficult to measure the inexorable evasion of one’s elastic capital when it is hidden in the depths of the body. This state of affairs can lead to diagnostic or therapeutic wandering, for patients looking for an effective management of painful syndromes during their care and life course, when the suffering person does not find any response to his pain. In addition, the appearance of clinical emergencies requires practitioners to find rapidly effective solutions to alleviate suffering and disability, or even to save patients’ lives. In the context of current health issues, it should be noted that loss of elasticity is at the heart of the seriousness of several respiratory diseases, such as SARS-CoV-2, which cause exaggerated and sometimes chronic inflammatory reactions that can destroy rather than protect lung tissue. Other pandemics with manifestations and complications associated with loss of elasticity are and will continue to be likely to affect our elastic capital and create an immune imbalance. These considerations, unequivocally, lead us to consider the protection of elastic tissue in the management and prevention of epidemics and endemic or chronic diseases.
1.3.1. Fibrosis of infectious origin
My own research topic concerned the analysis of elastic tissue and its alteration. I approached the notion of elasticity by studying the hardening of human tissues that occurs during the formation of scars and/or that occurs during bacterial or parasitic infections. After a first approach centered on the interaction between oral streptococci, caries formation and the development of secondary endocarditis, I became interested in what is called fibrosis, which was studied at the Institut Pasteur in Lyon in the laboratory of fibrosis physiopathology.
In certain infectious situations, tissues change and become rigid under the pressure of a strong synthesis of proteins and fibers, as if the body were building a barrier to defend itself against an aggression. This is the famous fibrosis experienced by some people whose cancer is treated with radiotherapy and who suffer from this side effect. Sometimes, in fact, the body’s defense mechanisms go haywire and the natural remedy becomes worse than the disease. This is precisely what happens to the alveoli of the lungs when COVID-19 results in fibrosis that impedes and in the extreme prevents breathing. The lungs lose their elasticity and we simply suffocate. This is respiratory distress. Those who have suffered from pneumonia, bronchitis, emphysema, bronchiolitis, cancer or other lung diseases can feel in their flesh what the slightest respiratory failure means. It is the anguish of the lack of air, something so essential. It is also the pain of expelling carbon dioxide, when the breath is lacking. Suffocation abolishes all plenitude, with the added bonus of fatigue and loss of energy. As the lungs are the gateway to the body, in contact with the external air, they are consequently the target of viruses, bacteria and other microbes, such as SARS-CoV-1 in 2003 and SARS-CoV-2 in 2019, but also the plague, the Spanish flu or tuberculosis. There is no reason for the litany of ailments to be unraveled when air pollution weakens the lungs and the concentration of urban areas facilitates contagion.
1.3.2. The great pandemics
Among the great pandemics that have permeated the history of humanity, the plague occupies a place at the top; during the ancient period, one of the first testimonies of a disease close to the plague rests on the writings of Thucydides in an Athens at war against Sparta. The pathology involved in this account was likely a form of typhus of bacterial origin, with pathogens (rickettsiae, for the curious) that attack the blood vessels and spread in the body. To stay within the framework of respiratory distress syndromes, pneumonic plague is rather expeditious. The plague bacillus (Yersinia pestis, again for the curious) invades the lungs where it infects and destroys the tissue of the alveoli, causing death in 2 or 3 days. It does not give the body time to react. The Spanish flu was not to be outdone, caused by an RNA virus like the coronavirus (we will see later on what this corresponds to). Studies suggest that the Spanish flu triggered a strong immune response and then a storm of cytokines in the lungs (like SARS-CoV-2), with destruction of alveolar tissue accompanied by bleeding and subsequent bacterial superinfection. Patients became blue and death followed rapidly as the infected lungs, filled with water, were no longer functional (this is called pulmonary edema).
In COVID-19, there is fibrosis of the lungs with respiratory stress, a side effect which led to the name severe acute respiratory syndrome (SARS). Let us discredit that the virus also induces renal failure, cardiac pathologies, alterations of the vascular wall as well as embolic accidents, chilblains related to vascular problems and intestinal pain. Alteration in olfaction, vision or hearing is not to be discredited, these being consequences of the nervous tissues being attacked. Moreover, the differences in the clinical picture between men and women, between children and adults, and even between people of different geographical origins complicate the management of the disease. Once again, all these pathologies or medical signs can be linked in one way or another to elastic capital.
There are other pandemics that have proven to be catastrophic for our lungs, with the formation of these hard and fibrous tissues that have lost their elastic functionality. An emblematic case is pulmonary tuberculosis, terribly active in the 19th and early 20th centuries and still the first infectious disease in the world today. The last tuberculosis epidemic occurred in France between the two world wars, with a peak in 1930. My two grandmothers died of it, both in their thirties. As for SARS-CoV-2, the microbial agent of tuberculosis (Mycobacterium tuberculosis, still for the same curious people and maybe others) nests and proliferates in the lungs where it can induce a strong reaction in the tissues, with an immune, inflammatory response and a reinforcement of the bronchial walls caused by a fibrous scar synthesis. Fortunately, in addition to the improvement of living conditions, the development of antibiotic treatments has made it possible to contain the disease and remove the specter of the dreaded iron lung associated with drastic hygienic measures. In order not to forget the severity of this scourge, archive images show a succession of patients caged for life in their iron lung. Tuberculosis is still rampant and is one of the leading causes of infectious deaths on our planet. And without being a prophet, we can predict that the emergence of strains resistant to all antibiotics heralds a difficult future for the actors of the health system and for the population. Fortunately, I’m talking about a time that people under twenty years old cannot know, that of sanatoriums, a time when it was prescribed not to spit on the ground to avoid spreading tuberculosis.
