Cell therapy extended the life of mice
Biologists rejuvenated the mouse by repairing the "aging center" in its brain
Scientists from the USA have discovered a special group of nerve cells in the brains of mice that control the work of the "aging program" and were able to slow down the process of their body's decrepitude by "seeding" this part of the brain with stem cells, according to an article published in the journal Nature (Zhang et al., Hypothalamic stem cells control aging speed partly through exosomal miRNAs).
"We found that the number of stem cells in the hypothalamus gradually decreases over time, and that this accelerates aging. As it turned out, the consequences of this are not irreversible – by replacing stem cells or adding the molecules they produce to the brain, you can not only slow down, but also reverse the aging of some parts of the body," said Dongsheng Cai from Albert Einstein College of Medicine in New York (in the press release Brain Cells Found to Control Aging – VM).
In recent years, a debate has been revived among scientists about what is the aging process and the death of humans and animals. Some biologists and evolutionists believe that this process is not random, and that it is controlled by a kind of "death program" – a certain set of genes that causes the body to become decrepit and die, giving way to a new generation of their own kind.
Trying to understand whether this is really the case, American geneticists have recently discovered a whole set of genes potentially related to the work of this "aging program", violations in the functioning of which can explain why long-lived people and African rodents, naked diggers, live several decades longer than the rest of the inhabitants of the planet and representatives of related im of animal species.
Tsai and his colleagues found out that a key part of this "program" can be hidden in the hypothalamus, the hormonal center of the human brain and all other mammals, observing how the brain of mice ages and how the life of small colonies of stem cells living in the nervous tissue of adult rodents changes as their bodies become decrepit.
As the scientists found, the number of stem cells in their brains remained stable until the mice began to age. Most of all, these processes affected the hypothalamus, whose stocks of stem cells began to decrease around the 10th month of life, a few weeks before the "official" onset of old age, and disappeared around the age of two, when rodents begin to die en masse.
Having discovered this unusual connection between aging and hypothalamic stem cells, Tsai and his colleagues decided to test what would happen if some of these cells were killed in middle-aged mice or a fresh portion of "blanks" of neurons and other brain tissues were added to the hypothalamus.
These experiments led to amazing results – mice with destroyed hypothalamic stem cells aged several times faster than their relatives from the control group, and rodents whose brains biologists introduced new stem cells, on the contrary, aged noticeably slower and lived 19% longer than normal mice.
The successful rejuvenation of mice forced scientists to go further and try to determine exactly how stem cells kept the mice from aging prematurely. The mechanism of their work is not yet fully clear, but Tsai and his colleagues found that the "blanks" of neurons produced a large number of microRNA molecules that control the work of different genes, and isolated them into the environment, from where they were absorbed by other cells.
Having isolated these molecules, the scientists injected them into the spinal cord of ordinary and rapidly aging mice and monitored whether this would affect their senility. Both groups of rodents lived noticeably longer than their relatives, which convinced Tsai's team that the aging process is "conducted" by RNA.
Now biologists are trying to understand which molecules slow down the aging of the body, brain and other organs of mice. Their discovery, according to Tsai and his colleagues, will be the first step towards finding an "aging program" and discovering methods for its partial or complete shutdown.
Portal "Eternal youth" http://vechnayamolodost.ru 27.07.2017