Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 37

Ageing is not a technical word introduced recently into biology to refer to a well‐circumscribed, specific phenomenon. It comes from common language. In the last century, biologists tried to give the word a precise biological translation. Yet it still has a vague biological meaning, despite all the progress accomplished in discovering the mechanisms of ageing. Indeed, so‐called ‘mechanisms of ageing’ are generally mechanisms involved in the average acceleration or retardation of death in a population or the manifestation of signs usually attached to ageing. This is the best proxy we have, but the results should always be viewed with care. On the one hand, manipulating certain mechanisms (e.g. of metabolism) may advance or retard the average age of death without those mechanisms being necessarily involved in ‘ageing’ in the first place. On the other hand, some syndromes or diseases, like progeria, may mimic ageing without much of a link between the pathological process at hand and physiological, normal ageing. Such are the consequences of having to use a vague word in biology. However, the importance of this process to the understanding of human health is such that this concept cannot just be abandoned. This chapter offers an overview of our biological knowledge of ageing.

There are two complementary approaches to the biology of ageing. In the populational approach, the focus is on the properties of ageing populations, some of which can be extrapolated to individuals. In the physiological approach, one investigates the mechanisms of ageing at the level of organisms, organs, tissues, cells, or even molecules.