Protein Klotho, supposedly protecting the body from early aging, has proven to be a potent brain booster that dramatically improved cognitive performance in young and elderly mice, according to an article published in the journal Cell Reports.
“This discovery made us think once again about the nature of the connections between the brain and the body. What happens to the brain after a large dose of Klotho is injected into the body of mice may resemble the effects in our body after exercise, which also improves memory and brain health. On the other hand, we don't yet understand how it works,”says Dena Dubal of the University of California at San Francisco (USA).
Over the past 10 years, scientists have found a lot of evidence that the health and many features in the functioning of the brain largely depend not on what happens inside the cranium itself, but on various processes and signaling molecules occurring in other parts of the body and contained in the blood.
For example, in April of this year, Stanford biologists proved that transfusing human umbilical cord blood into the body of an elderly mouse rejuvenated its brain and improved its memory. This happened because the umbilical cord blood contains an unusual enzyme TIMP2, which makes the brain cells "rejuvenate" themselves and start working the way they did in their youth.
Dubal and her colleagues have discovered another substance with similar properties that improves brain function both in old age and in youth, experimenting with the putative hormone of longevity - the protein Klotho, which is found in high concentrations in the body of long-lived people.
This substance, as shown by experiments on transgenic mice, whose DNA contains additional copies of the Klotho gene, significantly prolongs their life and at the same time slows down the aging of the brain, making them more intelligent in their old years.
Experimental results like these led Dubal's team to test what would happen if a large dose of this hormone was injected into the body of ordinary rodents, whose cells produce normal amounts of this protein.
These experiments quickly showed that the result of such injections was more than obvious - all mice, both young rodents and elderly individuals at an age equivalent to 65 years of age for humans, began to find a way out of the maze much faster and solve other memory problems and quick wits. The effect was especially noticeable among the elderly mice, which learned to remember the correct exit from the trap after taking Klotho, which they could not do before the start of the experiments.
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On average, they completed the tasks of scientists about twice as fast as individuals from the control group, and this effect persisted for at least two weeks after the biologists stopped injecting the hormone. Moreover, a similar effect can be achieved by introducing not whole molecules, but Klotho trimmings, which usually enter the bloodstream after the integration of its molecule into the cell membrane and cutting off the protein tail.
With their success, the scientists went further and tested how Klotho would affect the brain function of mice suffering from an analogue of Parkinson's disease, which results from the accumulation of protein "junk" in nerve cells. As it turned out, the injections of the hormone almost completely relieved them of spasms and other problems associated with the development of this disease and the massive death of nerve cells in the center of movement in the cerebral cortex.
How Klotho works, scientists do not yet know, since this substance cannot penetrate the barrier between the circulatory system and the brain and therefore cannot directly act on brain cells. So far, Dubal and her colleagues speculate that this protein somehow influences how often new long-term connections between neurons are formed, since blocking this process nullifies the positive effect of taking Klotho.
Further study of its effect on the body, as neurophysiologists hope, will help to understand exactly how this substance accelerates the brain, and will enhance its positive effects.