Scientists reverse brain birth defects in animal models

Prof Joseph Yanai and his associates at the Hebrew University were able to overcome neural and behavioral birth defects in mice by using mouse embryonic neural stem cells. These cells migrate in the brain, search for the deficiency that caused the defect, and then differentiate into becoming the cells needed to repair the damage.

Neural and behavioral birth defects, such as learning disabilities, are said to be particularly difficult to treat, compared to defects with known cause factors such as Parkinson’s or Alzheimer’s disease, because the prenatal teratogen — the substances that cause the abnormalities — act diffusely in the fetal brain, resulting in multiple defects.

In the animal model, researchers were able to reverse learning deficits in the offspring of pregnant mice who were exposed to organophosphate (a pesticide) and heroin. This was done by direct neural stem cell transplantation into the brains of the offspring. According to the scientists, the recovery was almost 100 percent, as proved in behavioral tests in which the treated animals improved to normal behavior and learning scores after the transplantation. On the molecular level, brain chemistry of the treated animals was also restored to normal.

However, the researchers have also discovered that the neural stem cells succeed before they die in inducing the host brain itself to produce large number of stem cells, which repair the damage. This discovery was published earlier this year in one of the leading journals in the field, Molecular Psychiatry.

The scientists are now in the midst of developing procedures for the least invasive method for administering the neural stem cells, which is probably via blood vessels, thus making the therapy practical and clinically feasible.

The research on the project was supported by the US National Institutes of Health, the US-Israel Bi-national Science Foundation and the Israel anti-drug authorities.