(ORDO NEWS) — Molecular biologists have discovered the relationship between brain aging and the function of macrophages, one of the key types of immune cells in humans and other mammals. Thanks to this, scientists have figured out how to improve memory and mental abilities. For this, it is necessary to change the nature of the vital activity of macrophages. An article with the results of their work was published in the scientific journal Nature.
“Experiments on mice show that by fine-tuning the immune system, you can literally reverse the aging of the brain. And experiments on cultures of human cells suggest that a similar rejuvenation of the nervous system will work in the human body,” said Katherine Andreasson, professor Stanford University (USA) and one of the study authors.
Experiments in recent years on the partial or complete rejuvenation of animals have generated a lot of controversy regarding the nature of such operations. As a result, scientists became interested in what blood components can accelerate or slow down aging. In a new study, Andreasson and her colleagues may have found the answer to this question.
They monitored how aging of the body affects the functioning of immune cells that are inside the brain or periodically enter it from the circulatory system. To do this, scientists removed them from the body of the elderly and young people and analyzed how the vital activity of the cultures of these cells differs.
It turned out that aging greatly influenced the behavior of macrophages – “cleaner” cells that are responsible for processing protein waste and fighting bacteria that enter from the outside. Typically, macrophages do their job correctly in young people’s brains. However, as they age, their work is rapidly disrupted. As a result, due to macrophages, chronic inflammation of the nervous tissue begins, which negatively affects the functioning of the entire nervous system.
After examining these violations, Andreasson and her colleagues have hypothesized why they occur. According to scientists, the body of older people produced unusually many molecules of the hormone PGE2, which is responsible for triggering inflammation. Because of this hormone, macrophages stimulate inflammation, PGE2 is produced even more, and the inflammation increases progressively.
Guided by similar considerations, the scientists tracked what would happen if the receptors located on the surface of macrophages, which are responsible for reading PGE2 molecules, were blocked. To do this, biologists injected into the brain of several elderly mice an experimental drug C52, which prevents the molecules of this hormone from binding to the surface of macrophages.
As a result, the memory and mental abilities of the mice injected with this drug improved dramatically about a month after the start of the experiment. Such rodents just as well remembered where the exit from the maze was, and solved other problems in the same way as their young relatives. Similar changes occurred in the pattern of activity of their nerve cells, as well as in their protein composition.
Scientists have achieved the same results with another experimental drug, PF-04418948, which cannot penetrate the blood-brain barrier, which separates the brain from the rest of the body. This suggests that negative changes in the work of macrophages do not occur in the tissues of the nervous system, but at the level of the whole body. The implications of this remain to be studied by biologists.
Andreasson and her colleagues hope that further experiments will be able to prove that a similar effect can be achieved in experiments on primates and great apes. If these experiments end with success, then it will be possible to proceed to tests on humans.
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