In publishing house “Eksmo” published the book of American neurogenetic browser and the New York Times Sharon Moalem “what if they’re not the enemy? Like sickness save his people from extinction”. “Pravmir” publishes an excerpt from the book about how the aging process protects us from cancer.
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Seth cook is the oldest living Americans with one of an incredibly rare genetic disorder. He fell all the hair. His skin is wrinkled. He has atherosclerosis. His joints ache due to arthritis. Every day he takes the aspirin with the aim of blood thinners.
He’s twelve years old.
From Seth syndrome Hutchinson – Gilford is a very rare disease, often referred to as progeria. It is believed that this disease affects only one in four to eight million newborns. This is a very cruel disease — its name in Greek means “prematurely old”, and that is the unhappy fate of those born with progeria people.
Children with progeria get older to ten times faster than people not suffering from this disease. When a child with progeria marks and a half years old, his skin wrinkled, and her hair falling out. Soon after this appear cardiovascular problems such as atherosclerosis, and degenerative diseases such as arthritis.
Most people with progeria die in adolescence from a heart attack or stroke is no known case, that they lived up to thirty years of age.
Syndrome Hutchinson – Gilford is not the only disease that accelerates the aging process, but it is the most heartbreaking, because it develops rapidly, and from the moment of birth. Another similar illness called “Werner’s syndrome” manifests itself after reaching the sexual maturity. Sometimes this syndrome is called progeria of adults.
After puberty, the aging process is accelerating, and people with Werner syndrome usually die of age-related diseases fifty or sixty years. Werner syndrome, although more common syndrome Hutchinson – Gilford, is still quite a rare genetic disease that affects only one person in a million.
Due to the fact that these accelerates the aging process of the disease are rare, they rarely become the subject of research (and therefore call them “orphan diseases”). However, this situation is beginning to change as scientists began to understand that these diseases are key to the understanding of normal aging process.
In April 2003, scientists announced that they managed to isolate a genetic mutation that causes progeria. This mutation occurs in the gene responsible for the production of a protein called “Lamin A”. Under normal circumstances, Lamin A is the frame of the membrane of the cell nucleus that contains all genetic information of the cell. Lamin a-like pegs that hold the tent — they are the basis for the membrane of the cell nucleus, which is based on this protein. People with progeria disrupted the structure of Lamin A, causing the cells wear out much faster.
In 2006, another team of scientists has established a link between the degradation of Lamin A and the normal process of human aging. Tom Misteli and Paola Scaffidi, researchers from the National Institute of health, USA, published in the journal Science article reported that in the cells of normal elderly people observed the same defects as in the cells of patients with progeria.
This is a very important discovery, which was the first confirmation that the characteristic of progeria accelerated aging is a normal process of human aging at the genetic level.
From this we can draw far-reaching conclusions. Since then, as Darwin described the mechanisms of adaptation, natural selection and evolution, scientists did not stop to argue about what kind of place in all this takes the process of aging.
The body simply wears out, like a favorite t-shirt who stretched and starting to tear? Or aging was the result of evolution? In other words, whether the process of aging accidental or intentional?
Progeria and the other accelerated the aging process of the disease point to the fact that he pre-programmed, is part of nature’s design.
Think about it — if one single genetic error can lead to accelerated aging in a baby or a teenager, the wear and tear of the body over time cannot be his sole reason.
The very existence of the progeria gene confirms that the aging process is controlled at the genetic level. This leads scientists to question that, no doubt you expected to hear. Are we all programmed to die?
Leonard Hayflick is one of the pioneers of the study of the aging process. In the sixties of the last century, he discovered that (with one special exception) cells are capable to divide only a limited number of times, after which the process of division stops and they begin to die. Limiting the number of cell divisions was called the Hayflick limit — this limit is from fifty-two to sixty divisions.
The Hayflick limit is associated with the loss of specialized genetic reserve, located on the ends of chromosomes called “telomeres”.
With each division the cell loses part of the DNA. To the loss of this information did not lead to detrimental changes at the ends of chromosomes are additional pieces of information — the telomeres.
Imagine that you need to make fifty copies of existing manuscripts, but copy center decided to seriously complicate your life. Instead of money after each copy he takes on the last page of your manuscript, and so a copy for a copy.
This is a serious problem in the manuscript of two hundred pages, and if for each of its copy should be given page, the last copy will only hundred fifty pages, and the one who gets her, will not receive a quarter of the story.
But you are not so easy to hold — you used to find solutions in the most intricate situations. You’ve added to the manuscript of the fifty blank pages, placing them at the very end, and brought in a copy shop the manuscript to two hundred and fifty pages. Now, all fifty copies of the manuscript will be the whole story entirely — the page will begin to disappear only when you decide to make fifty first copy.
So, telomeres are like an empty pages of manuscript in our analogy: with every new cell division they shorten, thereby protecting the important DNA. After about fifty or sixty divisions from the telomere in the end nothing remains, and then the cell is threatened.
Why in the course of evolution we need to restrict the number of divisions of cells?
The answer is simple — because of the cancer.
No other health-related word does not cause such fear and thoughts about death, like cancer. In our minds it is so closely associated with a death sentence in many families if start a conversation about cancer, then only in a whisper.
As you probably know, cancer is not a particular disease is a group of diseases characterized by failure in the process of cell division. In fact, some types of cancer is very well treatable — many of them are characterized by a high survival rate and the probability of full recovery than those common health problems, like heart attack and stroke.
As we have discussed, our body has several lines of defense against cancer. There are specific genes responsible for growth suppression of tumors. There are also genes responsible for creating specialized cancer hunters of the cells programmed to their search and destruction. Also there are genes responsible for repairing genes, cancer-fighting. Cells even have a built-in mechanism to commit a kind of Hara-Kiri.
Apoptosis — programmed cell death — occurs when a cell detects that appeared to be infected or corrupted, or when other cells detect the problem and “convince” the dangerous cell to commit suicide. Besides all this, there is also the Hayflick limit.
The Hayflick limit effectively inhibits cancer — if the cell fails and it becomes cancerous, the Hayflick limit still does not give her share in the pleasure, ultimately suppressing tumor growth before it begins to pose a danger. If the cells are capable of dividing only a limited number of times, and then exhaled, the division in some way is always under control, right?
Yes, but only to a certain extent. The problem is that cancer is a rather sneaky little villain, who in his cell the sleeves always got a couple of trump cards. One of them is an enzyme called “telomerase”. As you remember, the Hayflick limit is associated with telomeres — when they run out, the cell dies or loses its ability to divide. What does telomerase? It extends these are located at the ends of chromosomes are telomeres.
In healthy cells, telomerase is usually inactive, and telomeres continue to shorten. The cancer cells sometimes fails to activate telomerase so that the telomeres are restored much faster. When this happens, the genetic information is lost is much less, because embedded in the telomere reserve is never ending. Information about the expiration date programmed in the cell is erased, with the result that she is able to share without limits.
Thus, the success of cancer cells is usually associated with telomerase. More than ninety percent of the cells of malignant human tumors use telomerase. That’s how they become tumors — without telomerase, cancer cells would die after fifty or sixty divisions.
Learning to bypass the Hayflick limit with the help of telomerase, the cancer cells start to divide uncontrollably, leading to the dire consequences with which we are all so familiar. On top of that, successful cancer cells — the death of which we are most interested — found a way to bypass the apoptosis — programmed cell death. They ignore the call to suicide on the part of healthy cells, noticed that something was wrong. From a biological point of view it makes cancer cells “immortal” — they can divide indefinitely.
Currently, scientists are working to develop analysis to detect increased telomerase activity — such analysis would help the doctors in finding the hidden cancer cells.
Another exception, which is not subject to the Hayflick limit are stem cells, which are currently undergoing such intense controversy. Stem cells are “undecided” cells. In other words, they can divide, forming different types of cells. B-lymphocytes, which are antibodies — proteins produced by lymphocytes — able in the fission process to form only the same In lymphocytes and skin cells can create skin cells and no other.
From stem cells in process of division may be different types of cells, and the mother of all stem cells, of course, is the only cell, which began the development of each of us. It is obvious that the zygote (the cell produced after the Union of sperm and egg) must be able to produce all types of cells, otherwise we would remain zygotes.
Stem cells are not limited by the Hayflick limit — they are also immortal due to restoration of telomere with telomerase just as do cancer cells. No wonder why scientists see stem cells as it has great potential in treating disease and alleviating suffering — they are able to turn into anything and never run out of steam.
Many scientists believe that cancer prevention is the main cause in the course of evolution cells have restrictions on the number of divisions.
Of course, the Hayflick limit has its reverse side — in all have to compromise — aging. As soon as the cage reaches the limit, it is not capable of further division, and everything begins to crumble.
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