Long-lived nematodes: another record
A group of scientists from the University of Arkansas has shown that a mutation in a gene that is similar to the human gene involved in the formation of insulin and insulin-like growth factor (IGF-1) increases the life cycle of the nematode up to ten times. The work of Srinivas Ayyadevara et al. Remarkable longevity and stress resistance of nematode PI3K-null mutants is published in the journal Aging Cell.
The nematode Caenorhabditis elegans, a round worm about one millimeter long, is one of the most common laboratory animals, thanks to which many discoveries have been made. The patterns established for C.elegans often work in more highly developed organisms.
Scientists led by Robert Shmookler Reis have shown that worms carrying a mutation in a gene encoding one of the important components of the signaling pathway in which insulin and insulin-like growth factor are involved in humans live significantly longer than their "normal" relatives. In addition, they are more resistant to some external influences, for example, oxidative stress. True, mutants are more sensitive to high temperatures.
The average life expectancy of a nematode is two to three weeks. Mutant worms remained alive for six months, and some lived up to nine months. They developed slightly slower than worms that did not carry mutations, but throughout their lives their mobility and food preferences remained at a normal level.
In the last 15 years, scientists have found more than 80 mutations that have increased the lifespan of C.elegans. However, so far it has been possible to extend the life of the worm by a maximum of four times. To achieve this effect, in addition to introducing mutations, it was necessary to change the diet of the nematode, or rather, to reduce the amount of food consumed.
When trying to reproduce experiments on mice, it was possible to increase their life span by 1.7 times. In this case, it was also necessary to reduce the number of calories to the mice.
The mutation discovered by Rice's group has the strongest effect on increasing life expectancy and does not require a change in diet. In the future, Rice plans to repeat his success on mice. If the experiment is successful, in the future we can try to use this discovery to treat people.
However, Rice clarifies that it is not worth waiting for a rapid increase in human life expectancy to 800 years. "Worms have a short life cycle, and it's easy enough to 'force' them to live longer," he says.
Insulin reduces the amount of glucose in the blood, increasing its absorption by cells, and IGF-1 stimulates growth. Experiments have shown that disruption of the genes responsible for the production of insulin can lead to diabetes. Interference with processes affecting IGF-1 synthesis causes changes in mammals similar to those that Rice's group observed in C.elegans. Mice that partially lacked IGF-1 receptors live longer than normal and at the same time remain healthy. According to Rice, in humans, centenarians often have certain defects affecting IGF-1.
Source: UAMS Researchers Report 10-Fold Life Extension in a Complex Animal – University of Arkansas, 02/06/2008
Portal "Eternal youth" www.vechnayamolodost.ru11.02.2008