Stem cells restored heroin-damaged brain

The harm from heroin was canceledPyotr Smirnov, "Newspaper.
ru"Any addiction, be it gambling, drugs, alcohol or cigarettes, will sooner or later affect your health.

Joseph Yanai and Tamir ben-Hur from the Hebrew University in Jerusalem have found a way to restore the nervous system damaged by heroin inherited from a parent by transplanting nerve stem cells (HU scientists use stem cell therapy to reverse brain birth defects in animal models).

Pregnant mice who received the drug during the week before giving birth acted as "wayward mothers". The nervous tissue of the fetus suffers more than others from the bad habits of the parents, and it's not just a matter of greater susceptibility to poisons. Unlike other organs. the spinal cord and brain have a much more complex structural organization, and even the slightest violation often leads to serious consequences.

Although the work of the brain has not been a secret for scientists and doctors for a long time, it is not so easy to treat congenital anomalies. Even with the notorious Alzheimer's disease, there is a target for drugs – amyloid plaques formed along the vessels. In the case of the consequences of an "unfavorable and violent pregnancy", various defects are scattered throughout the entire volume of the brain.

It is not surprising that Yanai and colleagues chose the appropriate solution – stem cell transplantation. The mechanisms of action of this method of treatment, as well as the mechanisms of development of various brain defects, are not completely clear, but the result is both there and there.

Those who doubt the negative effect of drugs on the fetal brain should look at the results of Yanai's previous work, where relatively small doses of the drug led to significant damage to the hippocampus involved in the formation of emotions and memory. The formation of new cells in its dentate gyrus was reduced by 39%, and the cubs born coped with the traditional maze much worse than their counterparts.

After stem cell transplantation, everything, although not completely, fell into place.

Scientists promise to present the revolutionary results of their research at the annual congress of the International Society for Stem Cell Research, which will be held in Barcelona next year. Perhaps, the prospects for the clinical application of the method will become clear there. 

However, from a fundamental point of view, the patterns revealed by specialists are much more interesting. Firstly, for every 3,000 stem cells injected, only one survived. Secondly, most of the surviving cells turned not into neurons, but into astrocytes – supporting cells that isolate nerve tissue and provide it with nutrition.

But the transplantation activated "local", native stem cells – the number of their divisions increased dramatically (new neurons, the formation of which induced the introduction of stem cells, are shown in green). This helped to restore the structure of the hippocampus and immediately affected the functions: after a while, the mice coped perfectly with the maze. Thus, scientists have once again refuted the hypothesis that stem cells differentiate and are embedded in a tissue defect. At least in the nervous system.

Currently, Yanai and his colleagues are working out ways to inject stem cells not directly, but through blood vessels. But to do this, you will have to teach them to penetrate through all the layers of the barrier that isolates the nervous tissue from the rest of the body. Although, as recent studies have shown with another "barrier" organ – the placenta, this is not such a big problem.

There is another development perspective – obtaining nerve stem cells from the patient's own cells. Autologous, that is, using its own tissues, transplantation is not available due to the need to "climb into the brain" for stem cells. And a transplant from another organism, albeit genetically similar, is fraught with rejection reactions that can seriously disrupt the brain. For example, macrophages and T-lymphocytes were found in the nervous tissue of Yanai's "wards"; they were probably responsible for the destruction of most of the transplanted cells.

Now scientists already have access to induced pluripotent stem cells obtained from any piece of skin. And they, in turn, can be turned into neural stem cells.

However, do not think that now doctors will be able to easily restore the brain with congenital and even more so acquired injuries.

For example, a brain that has suffered from illegal heroin or completely legal, but no less harmful alcohol, each drop of which eventually deprives several nerve cells of life. Such procedures will remain a fantasy for a very, very long time – the interval from the first experiments on mice to clinical practice rarely takes less than a decade. To survive them, try to limit alcohol consumption, including in the next two weeks.

Portal "Eternal youth" www.vechnayamolodost.ru30.12.2008