[Epistemological views about vicious epigenetic circles due to aging].
Aging is not a disease. Age changes occur in every adult animal. They take place in all species. Yet, malignant tumours and neurodegenerative diseases grow with age. Nobody dies from aging. Death results from age-associated diseases. Muscular and digestive atrophies rise with age. But should it be said that digestive atrophy leads to malnutrition, or is it the contrary? Where is the chicken and where is the egg? We are enclosed in a vicious circle. A vicious circle is not a simple cycle. It is an irreversible phenomenon that happens when a system of objects is acting on itself. Vicious circles now reach the molecular level. This paper tries to show that the destruction of elastin and of fibronectin in connective tissues produces a self destruction effect. Von Neumann showed that a model of self reproduction with the help of reproductive automata could be imagined. We attempt now to show that nature has imagined a model to produce self destruction, trough degradation products of fibronectin and of elastin. This self destruction process is neither purely stochastic, nor genetically programmed. It is an epigenetical process. It is not present in the beginning, as an a priori instruction, it emerges. We try to give here a unusual specific philosophical definition of the word "emergence".
Miquel
Paul-Antoine
PA
Centre de Recherche et d'Histoire des Idées, CRHI, UMR 6045 CNRS, Université de Nice-Sophia Antipolis. pamiquel@wanadoo.fr
D000375:Aging / Q000235:genetics* / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003238:Connective Tissue / Q000378:metabolism; D004549:Elastin / Q000378:metabolism; D044127:Epigenesis, Genetic; D005353:Fibronectins / Q000378:metabolism; D005609:Free Radicals; D006801:Humans; D019359:Knowledge; D008954:Models, Biological; D018384:Oxidative Stress; D010446:Peptide Fragments / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011956:Receptors, Cell Surface / Q000378:metabolism; D013269:Stochastic Processes
D005353:Fibronectins; D005609:Free Radicals; D010446:Peptide Fragments; D011956:Receptors, Cell Surface; C054901:elastin-binding proteins; D004549:Elastin; D002118:Calcium