Setback for Parkinson's disease research

The first full trial of a new technique to treat Parkinson's disease using transplanted fetal brain cells has produced disappointing results, with serious side effects occurring in some patients. The study was published in the New England Journal of Medicine.

Parkinson's disease is caused by a gradual loss of dopamine-producing cells in the area of the brain that controls movement. Scientists at the University of Colorado School of Medicine in Denver and Columbia University in New York, attempted to replace these cells with similar cells from the brains of aborted fetuses. The study was the first supported by the National Institutes of Health (NIH) following a lifting of the ban on the use of federal funds for research involving fetal tissue.

Although the symptoms of a small number of patients improved, in several others they became much worse. Curt Freed, head of the University of Colorado team, thinks the side effects are due either to an overgrowth of the transplanted cells, or an overreaction to the dopamine (a brain cell communication chemical) they produce. 'Few in the field anticipated that too much dopamine would be an issue', neurosurgeon Thomas Freeman told Science last week.

Robert Meadowcroft of the UK's Parkinson's Disease Society said the results were disappointing, but did not spell the end of attempts to 'seed' the brain with either fetal cells, or in the future, stem cells. 'We need to learn how to switch these cells off once they have done their job' he said.