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Still Hope for Stem Cells in Parkinson's Disease Fri Aug 22, 5:26 PM ET By Karla Gale NEW YORK (Reuters Health) - Even though stem cell transplants have yet to clearly benefit Parkinson's disease patients, there is promise that further refinement of the technique could lead to long-term relief of symptoms. Parkinson's disease occurs when specific kinds of brain cells die. Patients with the disorder develop involuntary movements and tremor that progress over time because the brain cells no longer produce a chemical called dopamine. Drugs used to treat the disease work by replacing dopamine, but the drugs are less effective over time, so the disease usually worsens despite treatment. It was hoped that replacing the cells that produce dopamine would reverse the disease. Initial experiments where stem cells from fetuses were surgically implanted into the brains of laboratory animals were "spectacular," Dr. C. Warren Olanow, from Mount Sinai School of Medicine in New York, told Reuters Health. And when the same technique was first performed in patients with Parkinson's disease, their symptoms improved. However, Olanow and other neurosurgeons then conducted a trial in which 22 patients underwent surgery and 11 patients underwent a fake, or "sham," procedure. Two years after the surgery, the patients treated with stem cells were no better off than the ones who had the sham treatment. This was puzzling to the research team, because when the patients' brains were scanned, their cells looked almost normal, according to the report in the Annals of Neurology. In addition, autopsy results in five of the patients who died from unrelated causes showed healthy-appearing nerve cells in the region of the transplants and evidence that the stem cells had properly grown into the brain. So the doctors decided to reexamine their data based on different subgroups of patients. And in fact, in those who underwent the real procedures, there was a significant improvement for the first 9 months after surgery. This time frame coincided with the time in which patients were taking a drug called cyclosporine to prevent graft rejection. It appears that when this drug was discontinued, their bodies rejected the grafts and impaired the new cells' ability to produce dopamine. The researchers also observed that patients without advanced disease experienced more lasting benefits from the stem cells and that patients who had been treated with more cells were better off. More than half of the transplanted patients developed abnormal, disabling involuntary movements. Even though this is a serious symptom, Olanow told Reuters Health, he believes that it is not a sign of damage from the stem cells. Instead, he and his colleagues attribute it to poor graft survival that could not produce enough dopamine in the brain. "There has been a lot of hype about stem cell transplants and optimism that it could be a revolutionary new treatment," Olanow commented. While some may see his group's results as discouraging, he wants them to recognize that new techniques are rarely 100 percent perfect when they are first tried. Now he will perform more experiments in the laboratory to see if they could overcome the side effects by continuing immunosuppressive drugs long-term, treating the disease earlier, and transplanting more cells. SOURCE: Annals of Neurology, September 2003. SOURCE: Yahoo / Reuters http://tinyurl.com/kx66 * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn