[REVIEW] Since ancient times, humans have often in the pursuit of youth, life is not old. In ignorance of ancient times, people attempt to aid the gods or a stealthy power to refining "panacea" to achieve "immortality." Modern scientists are using increasingly sophisticated research tools, from the group, cellular, molecular, genetic level, layer by layer depth study of aging secret. Since the 19th century, scientists have put forward the doctrine of no less than 20 species, but a lot of theory has not been supported by experimental studies. The following select one representative to share with you.
Telomere length determines the biological life
In 2009, the Nobel Prize in Physiology or Medicine awarded to three scientists found that telomeres. They found that some of the people at both ends of the nucleus animals have something like a hat, called telomeres. Telomeres actually a DNA fragment from a special base sequence. The role of telomeres is to protect chromosome by telomerase to start, manufacture and maintain its function. Telomerase activity is a key factor in the regulation of aging. Young people, telomerase activity is large, easy to maintain and extend telomeres. However, in old age, telomerase activity is low, it is difficult to maintain telomere length, the telomeres shorten, and therefore aging will gradually revealed. When the length of telomeres shorten to a certain extent, caused the cells to stop dividing, leading to senescence and death. Therefore, scientists believe that telomere length determines the biological life, the longer the telomere, the longer life expectancy.
Harvard University oncologist Ronald De Binhuo according to telomere theory, the mouse experiment, the first successful reversal of the aging process. Test, De Binhuo make premature aging rats in a special way, so that these animals skin, brain, and other organs and viscera similar to 80-year-old then use drugs to stimulate successfully make telomerase reverse transcriptase back to life. Mouse after taking the drug for 2 months, a large number of new cells to grow, rejuvenated, revitalized. More surprising is that the original old male rats amazing regain fertility, once again reproduce.
Last year, drug manufacturers TA Sciences According to this theory also produced the first tablet to telomere-targeting.
However, the world is no free lunch. In this way anti-aging and may also increase the risk of cancer. Studies have shown that mice to enhance the activity of telomerase, will make them more susceptible to skin cancer and breast cancer. In fact, De Binhuo the successful development of a high level of telomerase reverse transcriptase also accelerated tumor growth.
Free radicals cause aging
In 1956, Harman first proposed a radical with the body aging and disease. Also known as free radicals or reactive oxygen radicals in the body when the following conditions occur more radical: processed foods, smoking, excessive drinking, mental stress, such as ultraviolet radiation. Free radicals in the body time and opportunity to find binding molecules can cause or converted into toxins penetrate into the interior of the cell, even to parts of the DNA located and destroyed.
Free radical theory has three core elements: (1) the aging of the cell components by free radicals caused by harmful (2) the radical mentioned here, mainly oxygen radicals, so the free radical theory of aging, and its essence is oxygen free radical theory of (3) to maintain an adequate level of in vivo anti-oxidants and free radical scavengers level can extend life and delay aging.
Based on this theory, the study of aging in 40 years of Russian scientist Vladimir developed an anti-aging drugs: " ion." " ions" is a strong antioxidant, can prevent oxygen from deep inside the cell, it can move within a specific small range, oxygen and cells in a dangerous form, and eliminate the negative impact of oxidation on the human body, lengthen a life span.
This anti-oxidant injection once norvegicus in vivo showed that the lives of mice doubled, while becoming healthier. In addition, with this antioxidant production drops due to geriatric made some blinding horses, dogs and rabbits restore vision. also himself as a "mouse", he cured one eye cataracts. The experiment is also conducting clinical trials, scientists behind, there are many doubts. Theoretically speaking, with respect to the telomere theory, antioxidants alone seems too simple to achieve longevity. People questioned, mainly in three aspects: First, the human body is like a huge "biochemical factory", a simple "antioxidant" can not solve all the problems. Secondly, oxide free radicals can cause many diseases, even to some extent in antioxidants can fight free radicals, but can not stop that may occur during the development of human infection of bacteria, gene mutation, metabolic problems, cancer cell invasion and so on. Finally, a total of 14 power of human cells 10, which is an astronomical figure, how can this antioxidant is injected into each cell in the game? People are eating, or injection?
Metabolic state of mitochondria affect life
Some theories suggest that mitochondria as cellular energy engine, in the aging process plays a key role. In addition to its supply of useful energy than people, but also produce harmful by-products - reactive oxygen free radicals that attack and damage various cell components. Eventually leading to cell loss can not be repaired because of its ability to maintain important functions of the body begin to age. Other studies also show that the fungi, worms and flies, some mitochondrial dysfunction can delay aging, but the mechanism of action has not been determined.
Gothenburg University School of Cellular and Molecular Biology research team found that a group of mitochondrial proteins called MTC with such regulation of the aging process. MTC mitochondrial protein synthesis is required for normal protein, but it can also affect the stability of the genome and affect cell damage and scavenging harmful proteins. When MTC cells lack certain proteins, other MTC proteins will be self-adjusting, the development of a new feature: they will get more reinforcement genome signal in order to compete with the protein damage, thereby prolonging life. This "aging-dependent control of the MTC" same signal path is used, and "caloric restriction" strategy active path.
Another study demonstrated that the mitochondrial DNA (mtDNA) damage can also cause aging.
Growth hormone and insulin affect aging
US researchers monkeys for 20 years after the study summary, reduce the intake of calories in the diet, extend their life, they die of heart disease, cancer and diabetes are reduced to one-third chance. Researchers in the past research on yeast, worms, flies and rodents also obtained similar results, which are able to demonstrate control calorie intake can prolong the life of the animal. This seems to imply, by reducing human diet to prolong life.
Scientists then conducted in-depth research. They finally found the biological basis of control calorie intake prolong life: growth hormone and insulin signaling pathway plays a key role. Southern Illinois University Andrezej Bartke of the Study Group on normal mice and mutant mice can not produce growth hormone in a series of experiments and found that the mutant mice was significantly reduced insulin levels, and compared with normal mice, its longer life and aging more slowly. Furthermore, recent studies have shown that insulin-like molecules that can affect many lives body aging and life cycle.
Gene hidden secrets of aging and longevity
A large number of research data shows the highest average life expectancy of species and life is fairly constant, so that the life of the species to some extent controlled by genes, so the animal or human body, naturally there will be related to the gene, which the scientists say the "aging gene" or "longevity gene." Aging and longevity gene refers to a gene is not a single gene, the gene generally refers to those who have caused or anti-aging effect. Scientists found that with aging and longevity related genes mainly in the following:
TERC gene. TERC gene can be manipulated to generate telomerase. In British scientists published in "Genetics" magazine paper, they found through research, people carrying the gene TERC, shorter telomeres, the situation with those who do not carry the gene TERC, larger than they aged 3 to 4-year-old man is similar, in other words, a person carrying the gene TERC faster aging 3-4 years. TERC gene is found in "Time" named the 2010 top ten scientific discoveries.
DAF-16 gene. ? Robin Meyer University of Birmingham team compared longevity, immunity and resistance close to the situation four kinds of worms, they found differences in DAF-16 activity with longevity, resistance and immunity complementary: DAF-16 the activity, the longer the life of the worm, anti-infection immunity, the better.
SIRT1 gene. Howard Hughes Medical Institute at Children's Hospital Boston, Dr. Frederick W. Alt and his colleagues analyzed a total of seven members of the family of SIRT genes, and found that the gene produces an enzyme SIRT - deacetylase capable of activating a variety of target molecules. Experiments show that, SIRT1 gene in mice can inhibit cell survival. They therefore presumed to improve mammalian SIRT1 gene may promote longevity.
SIR2 gene. Harvard Medical School, Paul F. Glenn, director of geriatric laboratory molecular biologist David Sinclair and colleagues found that four kinds of SIR2 genes associated with longevity, and the whole family of SIR2 genes are related to control life. SIR2 gene is one of the longevity gene was first identified.
PHA-4 gene. California Salk Institute biologist Andrew Dearing led the research team found that earthworms once ate "off" the bacteria PHA-4 gene, even if they go on a diet, and do not live longer than normal. While another test found that if you have a PHA-4 gene, earthworms even maintain a normal diet, life expectancy will be extended 20-30%. More surprising is that such a worm in addition to longevity than its similar, but also more dynamic than other worms.
CETP VV gene mutation. Nir Einstein College of Medicine Institute on Aging research team led by Dr. Barzilai found that good brain function in the elderly, with the CETP VV gene mutations in the elderly is not twice the gene elderly. Number of people live to a hundred elderly people having CETP VV accounted for 75%, and carry CETP VV elderly clearly have larger lipoprotein particles. CETP VV mutant protein can change cholesterol ester. It foreshadowed the CETP VV can not only live longer, but also to protect the integrity of the brain's cognitive functions.
FOXO3A genes. A survey of Kiel University School of Medicine have shown that human DNA in the presence of one kind "FOXO3A" genes can be called to help others live longer, compared with young people, this gene is present in the body of centenarians more common. In addition, the study also identified when there is a gene on FOXO3A nitrogenous bases in DNA, and the chance to live healthy people 90 years of age will be higher.
Anti-tune: just longevity genetic defects
Scientists are still struggling to find longevity genes control the aging time, a new study has revealed that the genetic defect is immortal, it is not conducive to evolution. In October 2011, an evolutionary biologist at the University of Sao Paulo, Brazil's Andre Martins (Andre Martins) published the results of this study. His computer simulation results showed that the test subjects, the emergence of an aging population, the population tends to become more advantageous. And we think we can live forever, "immortal legend" of the species, but the actual situation at a disadvantage. Thus, biologists speculated that a "longevity" of the population, may be a genetic defect on. Aging occurs or the presence of death update populations seem more competitive, and the evolution of a population, it is a very good news, when there is a change or a certain type of variation in function, can make the population of each generation slightly or to better adapt to the new environment. If a population is "longevity" of the population, the evolution of the population becomes "stagnant", the ability to adapt to the environment is poor.
So, we see that having a significant population aging and death would quickly adapt to the environment, because if not suited to the environment, they will be extinct away. This adaptability to some extent compensate for the adverse effects of the death of part of the population composition. Although Andre Martins models consider all aspects in great detail, but that can not be simulated and the degree of complexity of real-world analogy, but our real features of the world is changing fast, and many unknown elements.
Epilogue
At this stage, aging, death or human irresistible, perhaps in a few years or decades, centuries, humans can really clear the mechanism of aging and can control the aging process. It was a really good dream, this dream realized in the past, we only have to follow the law of nature, try to make their own flies every hour every day meaningful, so that their minds stay young. This we can do.
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