Is immortality the reality of tomorrow?
How much is immortality for the people Mikhail Levkevich, CNewsR&D
However, scientists claim the opposite. The results of research and discoveries in this area suggest that the first immortal people may be born already in this century.
Man is a unique species: he has achieved a lot thanks to his mind, created a complex society and reached great heights in science and technology. However, the personal merits of each individual, his soul and experience are inevitably crossed out by the common finale for all – death. About 100 years is all that is allotted to us, and this is terrifyingly little, given the short period of our "heyday" of strength and mind. The saddest thing is that unlike, for example, butterflies, who do not even know that they will live for one day, a person realizes the inevitable end and the transience of being.
A whole culture has grown up around the topic of death, for example, religions, in which the question of the transience of our life and the importance of soul salvation runs through the red thread. However, people are increasingly concerned not about her fate, but about the immortality of the mortal body. Is it possible to live forever, or at least much longer? We are not talking about 10-15 additional years of old age, which promise us a reasonable diet and a healthy lifestyle, but about prolonging existence by orders of magnitude and indefinitely. Needless to say, this would radically change the entire structure of our society and would be of great benefit to scientific progress – after all, today a scientist spends half his life only learning from the experience of his predecessors.
Until now, the idea of immortality has been the lot of fairy tales and fiction, but there is every reason to believe that the first immortal people will be born already in this century.
Why live forever?Many people claim that they would not like to live forever, apparently believing that this is just a prolonged old age.
From the point of view of nature, aging is a correct and necessary process. The organism that has lived its life, for sure, has accumulated injuries, diseases, parasites, and it is necessary not to feed it, but to make way for offspring. A similar natural defense mechanism of the species is present even in the simplest: bacteria that multiply by division do not fill the entire space even under ideal conditions, since degeneration occurs, manifested in "defective" offspring that are not capable of normal division.
The Aleutian sea bass lives at least twice as long as a human,
although there don't seem to be any special reasons for this
However, man is not a bacterium, he has intelligence, which makes any biological regulators optional. We have learned how to treat injuries, we make food ourselves, and we adapt the habitat to ourselves. We do not need a natural population regulation mechanism, because in the conditions of a developed civilization, an ageless person is able to live as long as he wants. Thus, the long–awaited moment comes - it's time to "cancel" unfair natural restrictions. Moreover, this is not even a metaphysical question – there are unique organisms that are potentially immortal, and they are not in eternal old age, but in an eternally young state or aging extremely slowly.
Only a few such examples are known. In the first place is the coelenterate hydra, which has unique regenerative abilities and is capable of endlessly renewing its body. Scientists also know the fish Sebastes aleutianus or the Aleutian sea bass, the life expectancy of this fish is so great that a person cannot observe signs of its aging. Currently, the age of the experimental individual reaches more than 200 years. Records of longevity and potential immortality are demonstrated by Pinus longaeva (long-lasting pine), which has been living for about 5 thousand years, and the Antarctic sponge Scolymastra joubin, which has been living for about 20 thousand years.
All their lives, these organisms have done nothing but consume food and excrete waste. A person could have done a lot more during this time. Besides, our life itself is an undeniable value. What can I say – even if not eternal, but a long, measured by millennia, existence could open distant stars to humanity, even if it takes several decades to reach them.
What prevents you from living forever?By and large, the human body is a machine capable of regeneration.
Our cells are constantly dying and being replaced by new ones, so the body theoretically has an unlimited service life. Of course, with serious damage to vital organs, for example, brain cells or lungs, complete regeneration is impossible, but this problem could be solved by growing new organs, replacing them with artificial analogues or stem cell therapy. But, unfortunately, the aging process that leads to death has other causes than the banal wear and tear of our living "machine". They are the most important mystery on the way to immortality.
The general signs of aging are well known: the appearance of wrinkles due to the disappearance of subcutaneous fat and loss of skin elasticity, atrophy and degeneration of internal organs, thinning of bones, reduction of muscle mass, decreased efficiency of the endocrine glands, deterioration of brain functioning, etc. There is a certain set of factors that trigger the process of dying of the body, to block this process means to gain immortality.
After the discovery of DNA, scientists were filled with optimism: it seemed that it was only necessary to find the gene responsible for turning on the aging mechanism, and then block it and live forever. However, after carefully studying the process leading a person to natural death, the researchers realized that there is most likely no "magic switch", and immortality is a complex of various factors, and of incredible complexity.
However, there is some good news. First of all, it was possible to detect several pathways of cellular signaling and transcription factors on which life expectancy depends. All of them are natural natural mechanisms that protect the body from adverse conditions. In particular, life expectancy is indirectly affected by the stress response of genes to lack of nutrition.
During starvation, many signals, such as insulin-like growth factor (IGF-1), are activated in the organisms of almost all living beings, from yeast to humans, as a result of which the body undergoes global physiological changes in order to protect cells. As a result, cells live longer and aging slows down. Unfortunately, it is impossible to achieve immortality by fasting, but IGF-1 significantly reduces the likelihood of developing cardiovascular diseases. In general, a decrease in the amount of IGF-1 increases the risk of death, which indicates the importance of this factor in prolonging life. In some countries, the production of IGF-1 has already begun using a genetically engineered method using recombinant DNA. Perhaps further work on an insulin-like growth factor will reduce mortality, and this is just one of the many mechanisms for prolonging life that our body has. Of course, it's not as easy as it seems – you can't introduce IGF-1 or something like that, and expect an increase to the years you've lived. There is a complex relationship with other factors, it is enough to note that the production of IGF-1 is associated with the effect of a whole bunch of hormones: somatotropic, thyroid, steroids, glucocorticoids, insulin. There is a long work to be done to put this mosaic into a complete picture.
How to live forever?Currently, the epigenetic theory of aging is becoming increasingly popular among scientists, which claims that it is not programmed in the human genome, but occurs due to permanent DNA damage, resulting in the death of the organism.
As you know, chromosomes have end sections, telomeres, which prevent connection with other chromosomes or their fragments (connection with other chromosomes causes severe genetic abnormalities). Telomeres are repeats of short sequences of nucleotides at the ends of chromosomes. The DNA polymerase enzyme is unable to copy DNA completely, so after each division, the telomere in the new cell turns out to be shorter than that of the parent cell.
Back in the early 1960s, scientists discovered that human cells can divide a limited number of times: in newborns 80-90 times, and in a 70-year-old – only 20-30. This is called the Hayflick limit, followed by senescence – a violation of DNA replication, old age and cell death.
Thus, with each cell division and copying of its DNA, the telomere shortens, like a kind of clockwork mechanism, measuring the life of cells and the whole organism as a whole. Telomeres are present in the DNA of all living organisms, and their lengths are different.
It turns out that almost all cells of the human body have their own "counter" that measures life expectancy. It is in this "almost", perhaps, that the key to immortality lies. The fact is that nature had to preserve some cells immortality. There are two types of cells in our body, sex and stem cells, in which there is a special enzyme, telomerase, which lengthens telomeres using a special RNA matrix. In fact, there is a constant "clock translation", due to which stem and germ cells are able to divide endlessly, copying our genetic material for reproduction and performing the function of regeneration.
The coelenterate hydra is able to regenerate even in the case of dissection in two.
A side effect of this unique ability is immortality
All other human cells do not produce telomerase and die sooner or later. This discovery was the beginning of a complex and sensational work, which in 1998 ended with a tremendous success: a group of American scientists was able to double the Hayflick limit of ordinary human cells. At the same time, the cells remained healthy and young.
It was very difficult to achieve this: telomerase reverse transcriptase genes were introduced into normal somatic cells with the help of viral DNA, which made it possible to transfer the abilities of sex and stem cells to ordinary cells, i.e. the ability to lengthen and maintain the length of telomeres. As a result, the cells "tweaked" by bioengineers continued to live and divide, while ordinary cells aged and died.
Just live forever?Yes, most likely, this is the cherished key to immortality, but, alas, it is very difficult.
The problem is that most cancer cells have a fairly high telomerase activity. In other words, the inclusion of the mechanism of telomere elongation creates immortal cells that can turn into cancer cells. Some scientists even believe that the telomere "counter" is an evolutionary acquisition designed to protect against cancer. Most cancer cells are formed from ordinary cells that are in a near-death state. Somehow, the constant expression of telomerase genes is activated in them, or the shortening of telomeres is blocked in another way, and the cells continue to live and multiply, growing into a tumor.
Because of this side effect, blocking telomeres is considered by many scientists to be a hopeless and dangerous process, especially when it comes to the whole body. Simply put, it is possible to rejuvenate certain cells, for example, the skin or retina of the eye, but the effect of telomerase unblocking on the tissues of the entire body is unpredictable and is likely to cause the appearance of many tumors and rapid death.
However, last year, scientists from Harvard Medical School gave us hope: for the first time they applied telomerase activation in a complex, not on a set of cells, but on a functioning organism.
First, the researchers completely turned off telomerase in mice, aging them. The mice aged prematurely: the ability to reproduce disappeared, the weight of the brain decreased, the sense of smell worsened, etc. Immediately after that, the researchers began to rejuvenate the animals. To do this, the telomerase activity in the cells was restored to the previous level. As a result, telomeres lengthened, and cell division resumed, the "magic" of rejuvenation began: the process of restoring organ tissues started, the sense of smell returned, neural stem cells in the brain began to divide more intensively, as a result of which it increased by 16%. At the same time, no signs of cancer were found.
The Harvard experiment is not yet a cure for death, but a very promising means of rejuvenation. Since scientists do not provoke the production of an abnormal amount of telomerase, but only return its level at the time of youth, it is possible to significantly prolong a person's life with minimal risk of tumors.
Is it real to live forever?Telomere manipulation is currently the most promising path to immortality.
But there are many obstacles here. First of all, oncological problems: even rejuvenation with the help of telomerase encounters an abundance of factors that increase the risk of cancer. Ecology, weakening of the immune system, diseases, improper lifestyle – all this creates a chaotic jumble of elements that makes the activation of telomerase unpredictable. Most likely, those wishing to gain immortality will have to be healthy and carefully monitor the environment. At first glance, it's difficult, but it's not too high a price. Moreover, science helps us in this: the huge funds allocated to the fight against cancer, not least help to develop life extension tools. It may not be possible to solve the oncological problem of telomerase in the near future, but the chance of soon discovering a reliable way to treat cancer is very high.
This month, scientists have achieved another major breakthrough on the path to immortality: they were able to completely change the aging process of adult stem cells, which renew old and repair damaged tissues. This can help in the treatment of many diseases that arise due to age-related tissue damage, and in the long term, and maintain health and good shape until old age.
The researchers studied the stem cells of young and elderly people and assessed changes in various DNA sites. As a result, it was found that in old stem cells, most of the DNA damage is associated with retrotransposons, which were previously considered "junk DNA". While young stem cells are able to suppress the transcriptional activity of these elements, older stem cells are unable to suppress the transcription of retrotransposons. Perhaps this is what disrupts the regenerative ability of stem cells and triggers the process of cellular aging.
By suppressing the work of retrotransposons, scientists were able to reverse the aging process of human stem cells in test tube culture. In addition, it was possible to return them to an earlier stage of development, up to the appearance of proteins that are involved in the self-renewal of undifferentiated embryonic stem cells. Adult stem cells are multipotent, in other words, they are able to replace any number of specific somatic cells in a tissue or organ. Embryonic cells, in turn, can turn into cells of any tissue or organ.
Theoretically, the new technique will allow in the future to launch the process of "absolute" regeneration, when an adult organism with the help of its own, modified into embryonic, stem cells will be able to repair any damage and maintain the body in excellent condition for a long time, and maybe forever.
Eternal life: the prospectsAnalyzing the results of the work on the "cure for death", we can say with great confidence that we will take the first steps on the path to immortality already in this century.
Initially, the process of "canceling" death will be complex and gradual. First, the immune system will be debugged and rejuvenated, which must cope with individual cancer cells and infections. The method is already known: scientists know that the aging of immune cells is controlled by the same telomeres – the shorter they are, the closer the death of the leukocyte. This year, scientists from University College London have discovered a new signaling mechanism in older people that deactivates white blood cells, even those with long telomeres. Thus, we already know two ways to rejuvenate the immune system. The next stage in prolonging life will be the restoration of specific tissues: nervous, cartilaginous, epithelial, etc. So, step by step, the body will be renewed and the beginning of the second youth, followed by the third, fourth, etc. This will be a victory over old age and a humiliating short life span for a reasonable being. A person's life path will become several times longer, and his health will be much stronger.
Sooner or later, a "universal" process will be found that takes into account many factors affecting the aging process. It will be closely related to the physiology of a particular person. Perhaps the "cure for death" will be based on a complex automated complex that constantly regulates the expression of certain genes. There is nothing fantastic in this technique: we have made great strides in automation, and over time DNA chips and programmable viruses will be able to "fine tune" our bodies. At this moment, it will be possible to finally put an end to a person's relationship with death – a person will irrevocably become the master of his fate and will be able to reach truly unprecedented heights.
Portal "Eternal youth" http://vechnayamolodost.ru26.09.2011