21 November 2008

Biological age can be determined by the activity of genes

Worms of youthPyotr Smirnov, "Newspaper.

Ru»Biologists have learned to measure the true age by analyzing the cells of the body.

Now any biochemical laboratory will be able to find out exactly how many "rejuvenating" products rejuvenate. So far, however, only for roundworms.

Thanks to plastic surgery, physiotherapy, dietetics and sports coaches, many of us look "much younger than our years." And what is "much younger than his years", or, who is not so lucky, "much older"? Intuitively quite understandable. But after all, such a formulation implies the presence of at least two ages – "passport" and "biological".

And if there is no question with calculating the first for law–abiding citizens, then calculating the "biological", or, as it is also called, "physiological" age is not an easy task. The main problem is the lack of a specific definition, because all comparisons are made with respect to physiological parameters averaged over the entire population.

Attempts to assess the "safety margin" of the body have been made repeatedly, but most often they were reduced to assessing the work of the cardiovascular, muscular and respiratory systems. And even then, everyone who wanted to capture himself in a physiology textbook, the author did not fail to take advantage of the uncertainty of the situation.

Simon Melov and his colleagues proposed to go a fundamentally different way and measure aging by gene activity. However, it has been possible to implement this idea so far only on the example of roundworms – the favorite of geneticists Caenorhabditis elegans.

Unlike humans, the organisms available to scientists live and develop according to a very clear pattern, because the lifespan of C. elegans worms, as well as drosophila or pure-line laboratory mice, can be predicted with accuracy up to several days. That is, their passport age practically coincides with the biological age, traditionally estimated by mobility and appearance.

This allowed Melov and co-authors of the publication in the specialized journal Aging Cell to construct a curve of changes in gene expression depending on age.

Measuring the amount of informational or matrix RNA (mRNA) corresponding to a particular gene is currently the most effective way to assess the "status" of processes occurring in a cell. After all, the entire metabolism is somehow tied to proteins that are built according to the mRNA matrix, which, in turn, is read from DNA depending on the needs of the cell.

In order to average the results, the scientists did not mince words and isolated RNA from the entire worm, simply dropping it into a test tube entirely. Having done this with a whole hundred defenseless creatures, geneticists selected a third of the 25,000 evaluated genes, the activity of which really changes with age, both passport and "biological". The genes of collagens, proteins that determine the strength of our tissues, fell into this group, as well as well–known markers of Alzheimer's disease and enzymes responsible for the metabolism of carbohydrates and fats.

The connection with aging of daf group genes controlled by sirtuin proteins, which are influenced by the extension of life so popular in the scientific community due to "calorie restriction of the diet", has been confirmed. The "countdown genes" encoding, among other things, the so-called "death proteins", death associated protein, have not escaped scientists either.

Using this "profile", Melov and colleagues tried to calculate the age of "wild" worms. Like their laboratory counterparts, they were also completely dissolved into RNA, having previously estimated the "biological" age in the traditional way. The calculation showed that the developed method has approximately 70% accuracy. Not bad for the first attempt, although the authors noted that it could be significantly improved by increasing the number of "participants" in the experiment and the estimated physiological parameters.

The new age assessment method has not only general scientific or laboratory, but even marketing implications. After all, with its help, you can check how effective the proposed methods of life extension and "rejuvenation" of the body are.

The experiments conducted so far, as a rule, showed an increase in chronological and only occasionally reproductive indicators. But the main goal of gerontology is to increase the "active period", during which the elderly according to the passport are really full–fledged members of society who do not suffer from age-related changes in body and mind.

It is not necessary to expect a repetition of such work on humans yet, because in this case it will be necessary to take dozens of biopsies and thousands of cells from different organs and tissues of our body, and then compare the data of the polymerase chain reaction with measurements of physiological parameters. And after all, no one guarantees that it will be possible to detect at least some kind of dependence.

Portal "Eternal youth" www.vechnayamolodost.ru21.11.2008

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