Biologists from California conducted repeated experiments on blood transfusion of young mice into the body of old rodents and did not confirm that such a procedure leads to any noticeable rejuvenation of the organs and skeleton of rodents, according to an article published in the journal Nature Communications.
“Our research shows that“young blood”by itself is not able to rejuvenate the body and somehow influence it. It would be more correct to say that “old blood” contains some molecules that we must destroy in order to reverse old age and slow it down, said Irina Conboy from the University of California at Berkeley (USA).
Since 2005, when Conboy and other biologists from the University of Berkeley conducted the first experiments on "gluing" the circulatory systems of several young and old animals, scientists began to be actively interested in the difference between "young" and "old" blood and whether it is possible to somehow use the first to renew and rejuvenate organs and the circulatory system.
Subsequent experiments both confirmed this phenomenon and made scientists doubt its existence. In their new work, Conboy and her colleagues have shown that this idea is fundamentally wrong, having created a special device that allows you to control the amount of "young" and "old" blood entering the circulatory system of "sewn" rodents.
Scientists say that testing the positive properties of "vampirism", as a similar procedure was called in the media, was extremely difficult in the past due to the fact that scientists could not accurately measure the strength of the action of "young blood" on an elderly organism. In particular, Californian biologists did not know how much of it gets into the rodent's body, and how the interaction of blood with two sets of organs affects their functions and the properties of the blood itself.
Using the "separator" of young and old blood they created, Conboy's group tested what would happen if they replaced about 50% of the blood in the body of elderly mice with "young" blood, and vice versa, if half of the blood in the body of young rodents was obtained by them from old individuals.
The results of these experiments were extremely unusual. On the one hand, the introduction of "young" blood did indeed somewhat rejuvenate the body of elderly rodents, and the effect of this was almost instantaneous.
Literally a day after the transfusion, the rate of cell renewal in their muscles increased slightly, but noticeably, and other positive effects from such a procedure appeared, which scientists wrote about earlier. Interestingly, at the same time, scientists did not notice any positive effects from such a procedure in the brain, in the liver and in other organs of the body.
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But on the other hand, the transfusion of "old" blood led to much more serious consequences - a few days after the replacement of blood, the muscles of young mice began to age rapidly, their brain cells began to die and the level of activity decreased, which was accompanied by a deterioration in memory and smell, and in others organs also developed typical "senile" disorders.
Such large differences in the body's response to "young" and "old" blood, according to Konboy, suggests that the press and some scientists were fundamentally wrong in attributing the rejuvenating properties of "young blood". In fact, the situation is exactly the opposite - “old” blood accelerates decrepitude, forcing body cells and organs to age faster, and transfusion of “young” blood simply stops this process, giving the impression that the body is rejuvenating.
Conboy and her colleagues are now comparing the chemistry of young and old blood samples, trying to isolate the molecules that cause the brain, liver, muscles and other tissues and organs to age as they age. Suppressing them, the Russian-American biologist hopes, will help us slow down or even stop old age.
