Study: Stem cells could restore cognitive function after brain irradiation
Human embryonic stem cells could be used to help restore cognitive abilities in patients after radiation for brain tumors, according to study appearing online Nov. 9 in the Proceedings of the National Academy of Sciences.

According to Charles L. Limoli, MD, and colleagues from the department of radiation oncology at the University of California, Irvine, cranial irradiation remains a “frontline” treatment for containing tumor growth. The problem is that if patients survive the treatment, it often results in side effects that include memory loss and learning deficits. This is caused, in part, the authors said, through radiation-induced depletion of stem/precursor cell pools in the brain, particularly those in the neurogenic region of the hippocampus.

To test the possibility of reversing this cognitive impairment the authors transplanted human embryonic stem cells into the hippocampal formation of rats two days after subjecting them to head-only radiation, and then analyzed them for stem cell survival, differentiation and cognitive function.

The authors found that rats receiving human embryonic stem cells were able to demonstrate superior performance on a hippocampal-dependent cognitive test—compared with irradiated rats that didn’t receive stem cells—four months after receiving the radiation treatments.

“Our findings provide the first evidence that such cells can be used to ameliorate radiation-induced damage of healthy tissue in the brain," said Limoli.