Though no tests have been conducted on humans yet, a series of experiments, first in cultures and then on mice, indicate that the drug promotes the growth of new neurons. In a classic behavioral test, mice that had been treated with metformin were able to form new memories faster than those mice who had been treated with a control substance.
Freda Miller, PhD, of the Hospital for Sick Children in Toronto and her colleagues, who conducted the metformin experiments, revealed that metformin could be an important aid to stem cell therapies by activating the aPKC—CBP pathway in neural stem cells, thus creating new neurons. Experiments in culture have been quite promising, showing that metformin promotes neurogenesis in human neural stem cells. In living mice, a 12-day treatment of metformin increased the number of new neurons by about 30%.
Interestingly enough, Chaim Pick of Tel Aviv University’s Sackier Faculty of Medicine and the Us National Institute of Aging’s Dr. Nigel Grieg have discovered that another FDA-approved diabetes drug, Exendin-4, significantly minimizes TBI animal models when administered after an accident.
To test the hypothesis, anesthetized mice were exposed to controlled explosions 8-11 meters away and their resulting injuries were then analyzed. Mice treated with Exendin-4 showed brain function nearly on par with the control group, while the group of mice who were exposed to the blast without being treated with Exendin-4 showed more severe brain injuries.
According to Chaim Pick, “Now we need to find the right dosage and delivery system, then build a cocktail of drugs that will increase the therapeutic value of this concept.”
Chaim Pick has worked with the U.S. military, conducting research to minimize the damage of soldiers exposed to the types of blasts that could be caused by IUDs or terrorist attacks. Exendin-4 could be used in the not-too-distant future as a brain injury treatment for U.S. soldiers.
While the possible breakthroughs offered by these diabetes drugs have yet to help human patients with brain injuries, they offer hope that new treatments are around the corner.