head drain

Two recent studies support the approach of Weizmann Institute of Science scientists - which offers hope to stroke and head injury victims

One of the reasons for the devastating damage caused by strokes and other head injuries is an increased production of a substance called glutamate, which destroys the brain cells that come into contact with it. As of today, it is not possible to fight excess glutamate and prevent the damage, because most drugs get "stuck" in the blood-brain barrier that prevents them from entering the brain, while the drugs that manage to penetrate it do not work as planned. A method developed by scientists from the Weizmann Institute of Science may, in the future, offer a way to prevent the damage caused by excess glutamate.

Prof. Vivian Teichberg from the Department of Neurobiology at the Weizmann Institute of Science was the first to point out, in 2003, a possible way to circumvent this problem - using a method based on a natural mechanism in the body to regulate glutamate levels. Glutamate is a neurotransmitter - a short-lived substance whose function is to transmit messages between nerve cells, and normally it is almost never found in cerebrospinal fluid. After a stroke or head injury, there is a "flooding" of glutamate levels in the brain, which causes overexcitation of the "flooded" nerve cells, and their death. Although most glutamate is created and consumed in the brain, it can be found throughout the body, especially in the blood.
Contrary to the methods that try to treat excess glutamate by directing drugs into the brain, Prof. Teichberg came up with an idea, in 1995, to use the capillary system that reaches every corner of the brain, and through it to transfer the glutamate from the brain into the blood. The system is based on tiny "pumps", located on the side of the brain facing the brain, and activated by the differences in glutamate concentrations in the brain and blood. Therefore, one way to speed up this transfer may be to lower the levels of glutamate in the blood - something that will increase the concentration difference and encourage the extraction of the substance from the brain. Prof. Teichberg also realized that he could enlist his help in a certain enzyme found naturally in the blood. Activating the enzyme, called GOT, causes it to look for and "hunt" the glutamate in the blood. Eight years later, Prof. Teichberg was able to show - in experiments he performed on rats - that the mechanism he proposed was indeed successful in lowering glutamate levels in the blood to a considerable extent.

A few more years later, Prof. Teichberg and his colleagues were able to show that in rats suffering from head injuries, in which the GOT enzyme was activated, the destructive damage to the brain cells was prevented. However, it was still not possible to determine with certainty that the protection of the brain cells is indeed a direct and exclusive result of the decrease recorded in the levels of glutamate in the blood and in the damaged area of ​​the brain. The "Yeda Research and Development" company issued a patent for the method.

Two new studies support Prof. Teichberg's approach - one done in the laboratory and a clinical trial in patients - provide proof that the activation of the GOT enzyme in the blood indeed contributes to the protection of brain cells. In the first experiment, conducted by Francisco Campos and his colleagues in the laboratory of Prof. Jose Castillo at the University of Santiago de Compostela in Spain, the scientists used magnetic resonance spectroscopy and showed unequivocally that the activation of the GOT enzyme in the blood of rats suffering from stroke-like brain injuries lowers the levels of glutamate in the blood and in the damaged area of ​​the brain, and also causes a significant reduction in brain cell death and edema - which usually appears in stroke cases. In the second study, a team of neurologists tested the levels of glutamate and the GOT enzyme in several hundred stroke patients during their hospitalization, in two hospitals. The doctors discovered that these two data are the most significant predictors of the patient's future condition - to what extent he will recover within three months, and the degree of brain damage he will suffer. Both studies indicate that treatment using GOT activation may improve the chances of recovery of patients who have undergone strokes and brain injuries, and even speed up the process.

In addition to stroke and head injury, excess glutamate characterizes other diseases, such as Alzheimer's, Parkinson's, multiple sclerosis, epilepsy, glaucoma, certain brain tumors and ALS. It is possible that treatments based on lowering glutamate levels will alleviate the symptoms of these diseases.