What is aging scientifically?
This is a natural biological process of destruction
There are a number of factors that influencelife expectancy: heredity, the state of internal organs and systems, socio-economic status and the degree of interest of a person in maintaining vigor and health. Therefore, a person’s biological age does not always coincide with the years he has lived.
According to the WHO recommendation, the following age categories are distinguished:
- 45-59 years - the average age;
- 60–74 years old - elderly;
- 75–90 years old - senile;
- over 90 years - long-livers.
How many years maximum can you live?
Scientists have found that genetically human lifeprogrammed for no more than 150 years. Now science is faced with the task of not only prolonging life, but also improving its quality. Geneticists and geriatricians believe that it is quite possible to achieve this.
Why are we getting old?
- Due to the accumulation of mutations
It is based on the fact that genes are capable ofchange (mutate), accumulating these changes throughout life. And since each gene is responsible for several traits (pleiotropy), mutational changes entail changes in human physiology. Mutations can occur both for no reason and under the influence of various environmental factors (stress, infectious agents, etc.). The mechanism operates at different stages of extinction. With the accumulation of a large number of mutations, a person dies.
- Due to the toxic effects of free radicals
In this case, the cause of aging isa chemical process in which aggressive molecules with an unpaired electron are formed at the cellular level. When they collide with other molecules, they take the missing electron for themselves, becoming neutral, but destroy other molecules.
The causes of human aging are linked to excessfree radicals. Scientists have identified an enzyme that neutralizes free radicals (superoxide dismutase - SOD), the amount of which determines the rate of age-related degradation. This theory is well founded. But scientists are convinced that free radicals are not the only cause of extinction.
- Due to the mechanism of apoptosis
In a new organism, all types of cells are renewed quickly and completely replace the dead ones, since each cell contains a mechanism of apoptosis—self-destruction after a certain time.
However, in older individuals, this mechanism givesfailure, and the number of newly formed cells in the body becomes less and less than the number of dead cells, which leads to general degradation of the body. Apoptosis can be accelerated when cells are damaged. So, if rapidly dividing stem cells (including bone marrow cells) are damaged by radiation, the risk of developing malignant tumors increases.
- Due to telomere theory
The theory is that the nucleus of each cell contains 23 pairs of chromosomes, which are twisted spirals with small tips at the ends called telomeres.
According to this theory, telomeres are most accuratedetermine the biological age of a person, since they are reduced with each cell division. The shorter the telomeres, the longer it takes to separate it from the primary mother cell. This theory is very reliable, but it does not explain why the nerve and muscle cells of a mature organism do not divide, the telomeres in them do not change their level, but the cells age just like everyone else.
How do we age at the cellular level that was previously known?
- Cells that are characterized by primary aging.
- Cells in which aging is an alloy of their own age-related changes, as well as external influences.
- Cells in which, under natural conditions of existence, aging is mainly secondary and indirect.
The first group includes nerve cells,many connective tissue elements; to the second - muscle fibers, cells of glandular formations, liver, kidneys; the third - the epidermis, epithelium in many organs, and more. Cells of the third group are also characterized by their age-related changes, but the pace and severity of regulatory shifts largely precede these changes.
What has become known about aging?
A new theory was proposed by molecular biologists andbioengineers at the University of California, San Diego. They studied the cellular processes in the yeast Saccharomyces cerevisiae. Using the methods of microfluidics and computer modeling, scientists have found that about half of the cells age in the process of a gradual decrease in the stability of the nucleolus, a region in nuclear DNA where the formation of key components for protein synthesis occurs. The other half of the cells develop dysfunction of mitochondria, the power plants of the cell.
According to research, yeast cellsembark on one of the paths of aging at an early age and follow them throughout their lives. During the study, experts found that cells with the same DNA and in the same environment can age in very different ways.
Scientists have tried to figure out how to takedecision on which path the aging will take place. They were able to discover the molecular circuitry that controls this process. Then, using computer simulation, they successfully reprogrammed this scheme and created another aging pathway, in which the cell's lifespan increased.
The specialists intend to continue similar studies on other cells and organisms, including human tissues.
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