SCIENTIFIC THOUGHT. Why do we grow old?

in #story6 years ago

More than 150 thousand people die on the planet every day. It is clear that some of these deaths are due to accidents, but most are death as a result of aging. Let's try to figure out why we are getting old and whether it is possible to stop it.

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Source photo

On Earth live organisms that can live to very advanced years. Scientists are trying to figure out how they do it. They study the mechanisms of cell death, try to understand how genes make us grow old and how our behavior affects our aging. All of us are very complex sets of cells that can reproduce similar ones. Death is something that unites all people and almost all animals. In most cases, it becomes the result of aging. At the biological level, our body begins to age when it reaches sexual maturity. After that, we gradually lose the ability to combat physical stress and to keep homeostasis. We also lose the ability to cope with diseases.

Technically, there is no such thing as death from old age. Everyone has some cause of death, but gradually everything grows old. In the animal world, there are creatures (we are talking about cold-blooded animals that experience so-called negligible aging or aging that can not be observed), which do not lose the ability to reproduce over time and the mortality rate does not increase with age. In fact, these animals remain at the same level of physical state, until something terrible happens to them: a disease or attack of a predator. For example, the Galapagos turtles can live up to 170 years.

Scientists began to study aging at the cellular level and found out that our cells are programmed to wither and die. Any somatic, that is, an incomplete cell, is constantly divided, creating a copy of itself. In the early 60s of the last century, young scientist Leonard Hayflick studied fetal cells. He discovered the limitation of the number of human cells. Cells die after about 50 divisions and have signs of aging upon reaching this limit. This happens about 9 months, but in other animals this limit can be more or less.

Scientists were interested in the question: if there is a limit, what are its causes? A possible answer to this question is the chromosomes. The human cell ceases to divide when it can no longer recreate its telomeres - the end sections of the chromosomes that protect the genes from errors. Telomeres are created with the help of an enzyme called telomerase. After each cell division, the telomeres become shorter than the maternal cells. This is the limitation of divisions. The cells are divided until the telomeres are long enough to protect the chromosomes. So why do scientists not do anything to make the cells share forever?

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Telomery

In fact, cells that have such properties are found in our body. These are cancer cells. These cells can create their own telomerase so that they can divide as many as they want without damaging their chromosomes. It is because of their active division that tumors are formed.

The cause of aging lies in our genes. Here, studies have touched a small annelid worm called Caenorhabditis elegans. These worms are an excellent object for study, since their life cycle is only 14 days and they have about 20,000 genes.

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Caenorhabditis elegans

In 1993, Cynthia Kenyon, a biologist at the University of California, discovered that these worms are aging because of just one gene. It's called DAF-2. Cynthia disabled this gene, and this worm lived instead of 14 whole 28 days. The researcher discovered another gene, which has the opposite function. It's called DAF-16. This gene controls the production of antioxidants and other pathogens. Kenyon also found out that the aging gene acts through the restriction of the action of the longevity gene: if one is damaged, then the other starts to act more actively. But what does this have to do with us?

As for humans and other mammals, we are talking about the so-called growth gene, which is called insulin-like growth factor 1. When scientists muffled the activity of this gene in mice, the cells became less damaged by oxidation. The organs became less susceptible to diseases associated with aging, but, unfortunately, these experiments have so far only been carried out in mice.

Another reason for aging is calories. Despite the fact that we need calories to live, they also activate the aging process. The cause of their harmful effects on the body is the stimulation of the work of an insulin-like growth factor 1. But while in these studies a lot of dark spots and much more will have to be carefully studied.

And what do you think about this? Would you like to live forever or at least for a very long time?

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