Theories of Aging

October 30, 2011

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Aging is the changes that affect all levels of organization of living matter, and the legitimate age-related changes in the body called homeorhesis .

Today there are many theories that attempt to explain this and aging adaptive-regulatory theory of aging   and not less interesting theory of apoptosis But none of them is able to fully explain the complex process that occurs at all levels of the body, from the molecule, then - cell, tissue and organ. After all, every year the number of new knowledge about the process increases, which leads to the birth of new theories of aging.

Telomere theory of aging

In the 1960s. US gerontologist L. Hayflick, it was found that human skin cells can divide only a limited number of times (40 to 60), however, to explain this phenomenon he could not. After 10 years, AM Olovnikov, at that time was one of the members of the Institute of Biochemical Physics, Russian Academy of Sciences, on the basis of the Hayflick, has suggested that limit cell division   because every time a cell divides chromosome   a little shorter.

Science known that chromosomes have end portions ( telomeres ) That, as a result of the doubling, gradually shorten, and eventually the cell can no longer divide, and then it loses its vitality. That is what is the cause of aging, according to the telomere theory. Hypothesis Olovnikov was exposed in mid-1980. When opened the enzyme telomerase Who was able to finish building the truncated ends of the chromosomes in the tumor cells, allowing them to be immortal. Incidentally, the limit of 50 divisions is not valid for every cell, e.g., stem   or cancer cells   can share countless times.

By the way, AM Olovnikov subsequently decided that this theory does not explain the causes of aging, and it was nominated Redusome theory of aging . In accordance with the precepts of its linear DNA molecule   redusomes (a redusomes   - A small nuclear particle, located in chromosome subtelomeric parts) gradually shortened due to a decrease of its linear DNA molecule covered proteins That reduces it contains different genes. That is shortened redusomes DNA molecules provides a means of biological time measurement, and is the cause of aging.

Elevating theory of aging (neyroendokrinologicheskaya theory)

In the 1950s. Soviet scientist VM Dil'man put forward the idea that there is a single regulatory mechanism that determines the patterns of changes in various systems of the body associated with age. The main element of this mechanism acts hypothalamus . More specifically, the main causes of aging are decreasing over time, the ability of perception of the level of the hypothalamus hormones   in blood, and it is sensitive to signals of nervous system.

Consequently, it is increasing the number of circulating hormones, leading to various diseases peculiar to old age ( obesity . hypertension . menopause . diabetes . atherosclerosis   and others). All this leads to the aging and death.

Subsequently, on the basis of these studies and observations it has been found that this leads to age-related changes in the reproductive system. Dil'man argued that aging - a by-product ontogeny   - Development of an organism. It Elevating theory of aging has contributed to the discovery of new approaches to the prevention of premature aging, and related diseases.

Adaptive-regulatory theory of aging

It was developed by Ukrainian gerontologist VV Frolkis in 1960. It is based on the idea that aging is genetically programmed process, but VV Frolkis suggested that age-related development is determined by the balance of the aging process and the process of "anti-aging" ( vituakt ) Aimed at increasing life expectancy. The scientist developed genoregulyatornuyu hypothesis that the primary mechanism of aging is a malfunction of regulatory genes. A violation results in gene regulation diabetes . atherosclerosis . Parkinson's disease   and Alzheimer's . It was immediately put forward the concept genoregulyatornoy therapy for the prevention of age-related pathologies.

The theory of free radicals

This theory was put forward by scientists E. Harman and N. Emmanuel in the 1950s. According to the free radical theory, causes disruption of the cells is the action of free radicals - oxygen species, which are synthesized in mitochondria . Oxygen is required for cellular respiration cells, but part of the oxygen can be converted into so-called "active" oxygen species. Free radicals are able to leave the place where there is a need for it and is able to damage DNA . RNA . cell membrane lipids   and proteins . From an excess of free radicals helps substances with antioxidant properties, such as various vegetables and fruits, as well as Vitamins A . E   and FROM .

The theory of apoptosis (cell suicide theory)

By Academician VP Skulachev. According to the tenets of the theory, apoptosis   - A programmed process of cell aging. Each cell, after the passage of their life cycle and it happens mutation must die and give way to new, young cells. This hypothesis carries the same meaning as the theory of telomeric aging. When cell apoptosis "samorazbiraetsya", and its parts can be used in neighboring cells as a building material. So it is with the mitochondria if they produced a surplus of free radicals. When the mitochondria are too many dead, their decay products leads to apoptosis, ie suicide. And aging appear when the body's cells are born less than a new born.

The theory of "aging in error" (or the theory of somatic mutations)

This hypothesis was proposed by physicist M. Szilard in 1954 in the United States. According to his research, ionizing radiation   shortens the life of living organisms, and there is a mutation in DNA molecules, which leads to aging. Thus, the cause of aging at Szilard are mutation . However, the theory of somatic mutations do not explain why aging people who are not exposed to radiation. Follower Szilard - M. Orgel argued that with age, the body accumulate genetic damage caused by mutations - accidental and caused by various factors ( seeks . viruses . ultraviolet ) Accumulated DNA damage that leads to aging and wear of the organism.

There are other theories of aging, for example, theory of cross-linking It has a similar meaning, like the theory of free radicals, Theory disposable (consumed) disputes   and several others.

Thus, the complex mechanisms of aging. Today there are several theories that something contradict each other, and in some ways - complement. In modern biology Ageing paid much attention, and perhaps in the future, with the deepening of knowledge about the problem, the means will be found to slow down aging and extend human life.