Aging is a natural process in which parts of the body and the entire system as a whole gradually degrade. However, these processes can be slowed down if you understand how they proceed. A group of American scientists from the University of California discovered the basic mechanisms of aging and developed genetic methods for prolonging life. Here’s how the new research will affect our knowledge of aging.
What is scientifically aging?
This is a natural biological process of a destructive nature. Gradually, during aging, the body’s work is disrupted, and its survival rate in the environment decreases. This leads to a limitation of the general capabilities of the body, the appearance of age-related chronic diseases, and an increase in the risk of the possibility of death. In addition to physical degradation, there is also a decrease in mental abilities.
There are a number of factors that affect life expectancy: heredity, the condition of internal organs and systems, the socio-economic situation, and the degree of a person’s interest in maintaining vigor and health. Therefore, the biological age of a person does not always coincide with the years 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 can you live maximum?
Scientists have found that human life is genetically programmed for no more than 150 years. Now science is faced with the task of not only prolonging life, but also improving its quality. Genetics and geriatricians believe that to achieve this is quite realistic.
Why are we getting old?
Due to the accumulation of mutations
It is based on the fact that genes are able to change (mutate), accumulating these changes throughout life. And since each gene is responsible for several features (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 is a chemical process in which aggressive molecules with an unpaired electron are formed at the cellular level. Faced with other molecules, they take away the missing electron, becoming neutral, but destroy other molecules.
The causes of human aging are associated with an excess of free 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 reason for extinction.
Due to the mechanism of apoptosis
In the new organism, all types of cells are renewed quickly and completely replace the dead ones, since each cell has a mechanism of apoptosis – self-destruction after a certain time.
However, in older individuals, this mechanism fails, and the number of newly formed cells in the body becomes less and less than the number of dead cells, which leads to a general degradation of the body. Apoptosis can accelerate with cell damage. 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 – telomeres.
According to this theory, telomeres most accurately determine the biological age of a person, since they contract with each cell division. The shorter the telomeres, the more time separates 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 in the same way as everyone else.
How do we age at the cellular level, which was previously known?
- Cells that are prone to primary aging.
- Cells in which aging is an alloy of their own age-related changes, as well as external influences.
- Cells in which in vivo aging is mainly secondary and indirect.
The first group should include nerve cells, many connective tissue elements; to the second – muscle fibers, cells of glandular formations, liver, kidneys; to the third – the epidermis, epithelium in many organs and more. The cells of the third group are also characterized by their own age-related changes, however, the rate and severity of regulatory changes largely precede these changes.
What has become known about aging?
The new theory was proposed by molecular biologists and bioengineers at the University of California, San Diego. They studied the cellular processes in the yeast Saccharomyces cerevisiae. Using the methods of microhydrodynamics 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 cell’s energy stations.
According to the study, yeast cells embark on one of the pathways of aging at an early age and follow them all 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 the decision is made, along which path aging will occur. 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.