No one knows just what causes Parkinson’s disease, but 400,000 to 1 million Americans suffer its crippling effects. When a brain is functioning normally, cells within a region called the substantia nigra initiate motor activity by releasing the chemical messenger dopamine. In a Parkinson’s sufferer, those cells gradually die off, causing a progressive loss of muscle control. The disease causes tremors, rigidity and, eventually, paralysis. The traditional therapy, a drug called levodopa, can relieve the symptoms by forcing the dying cells to produce more dopamine. But the treatment is nearly as awful as the disease-psychosis is one common side effect-and it does nothing to address the underlying problem. The dopamine-producing cells continue to die, often rendering the drug useless within 10 years.
Fetal-cell therapy cuts closer to the root of the problem. Its goal is not to stimulate dying brain cells but to replace them. Neurologists have long reasoned that if they could harvest substantia-nigra cells from the embryonic brain of an aborted fetus and inject them strategically into the brain of a Parkinson’s sufferer, the cells might take root and thrive, creating a fresh source of dopamine. The trick has proved feasible in laboratory animals, and the studies reported last week offer convincing evidence that it can work just as well in humans. The new reports describe 13 fetal-cell transplants performed since 1988. The three research teams used different techniques and different measures of success. But there was a common thread to their findings. Ten of their 13 patients improved after treatment, and brain scans indicated that the transplanted tissue was responsible.
Researchers at the Yale School of Medicine treated four patients, grafting fetal cells to only one side of the brain. The sickest patient died a few months after the operation, but the other three showed modest improvements, even while reducing their medications by as much as 60 percent. Doctors at the University of Colorado Health Sciences Center, in Denver, claimed more impressive results in a group of seven patients, most of whom received implants in both sides of the brain. Five of the seven registered gains on tests that measure specific motor skills. None returned to normal, but some reclaimed crucial aspects of their lives. A 64-year-old woman who’d suffered “unanticipated falling spells many times a day” now falls less than once a month, the researchers report, and a 53-year-old man who couldn’t speak intelligibly or drive a car now does both.
A team based at the University Hospital in Lund, Sweden, described still more dramatic results in a couple from San Jose, Calif, who had developed a permanent Parkinson’s-like syndrome after injecting tainted synthetic heroin in 1982. Both patients received liberal injections of cells taken from several aborted fetuses, and both had their lives transformed. One of them, 40-year-old Juanita Lopez, had been unable to feed, bathe or dress herself before undergoing surgery. Two years later she “could perform any movement,” despite a 70 percent reduction in her medication, and her muscle rigidity had “virtually disappeared.”
Together, the new findings represent “a real step forward,” says Dr. Stanley Fahn, a Parkinson’s specialist at Columbia University. The next step is to determine, through larger studies, which implantation techniques produce the best results and how long the benefits might last. Such studies are hard to organize without help from government research agencies. Ronald Reagan barred federal funding for most fetal-tissue research in 1988, and President Bush has upheld the ban despite opposition from Congress and the National Institutes of Health. More than 40 health and research groups have protested the moratorium, and President-elect Clinton is now promising to lift it. Not surprisingly, researchers are elated. “I’m reminded of the episode in ‘The Wizard of Oz’ when the house falls on the witch,” says Dr. William Langston, a California Parkinson’s specialist who collaborated on the Swedish study. “All of a sudden, everything has turned from black and white into color.”
