Brain stem cells help Parkinson’s monkeys

Monkeys with a Parkinson’s disease–like disorder showed signs of improvement after receiving transplants of human-brain stem cells. The treated monkeys began to walk and eat again, while their untreated companions continued to degenerate.

In Parkinson’s, neurons that produce the nerve-signal transmitter dopamine die off. Researchers have implanted fully mature dopamine-producing neurons into the brains of a few people with Parkinson’s, but those cells sometimes produced too much of the chemical, causing spasms.