Parkinson’s implants survive in brain
By Nathan Seppa
Human embryonic stem cells transplanted into the brains of people with Parkinson’s disease survive and grow better in patients under age 60 than in older patients, researchers report. Physicians have been transplanting the cells as a new source of dopamine–a brain chemical necessary for muscle movement that’s in short supply in Parkinson’s patients.
However, side effects seen in some of the patients suggest the cells might be overproducing dopamine. These transplant patients exhibit jerky movements similar to those often seen after long-term use of the dopamine-replacement drug levodopa, says study coauthor Curt R. Freed, a neuroscientist at the University of Colorado School of Medicine in Denver. This drug typically works initially but can eventually cause side effects.