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Source of this story and video on the Retinal Cell clinical trial: http://tinyurl.com/3vh76 Retinal cells help Parkinson's 7/10/2004 3:27 PM By: Ivanhoe Broadcast News According to the American Parkinson Disease Association, more than 1.5 million people in the United States are living with Parkinson's disease. Clinically, the disease is characterized by a decrease in spontaneous movements, gait difficulty, postural instability, rigidity and tremor. Men and women alike are affected. It's more common in the over-60 age group, even though there are an increasing number of patients of younger age. The drug levodopa has been the standard treatment for Parkinson's disease. Once it reaches the brain, levodopa is changed to dopamine, which replaces the same substance that patients with Parkinson's disease lack. Treatment with levodopa does not, however, prevent the progressive changes of the brain that are typical of the disease. Levodopa may also produce side effects in some people due to its conversion to dopamine before reaching the brain. "You start off with replacing the [dopamine] that is absent and that corrects the problem in the initial stages really quite well. The problems is, that as the patients get older, the number of cells drop off and the symptoms get worse and within five years, most of the patients are having very bad side effects from medication. You get what's called 'on-off' effects. Patients go from being frozen and unable to move to being uncontrollably moving. So, this fluctuation comes when the medicines are not working effectively," Dr. Roy Bakay, from Rush University, said. Bakay and other researchers are involved in a clinical trial to replace a certain type of cell that produces levodopa. "There are cells in the body that are capable of naturally producing the L-dopa, the precursor to dopamine," he said. His team is using retinal cells taken from the back of the eye. "If you look in the back of the eye, there are dark cells in there, black cells that keep the light from bouncing around inside the eye," Bakay said. "These cells are very important for a large number of things that they do and one of the things that they do is to produce pigment. A by-product of that pigment is the L-dopa. The same drug that is used orally for Parkinson's patients." In this study, Bakay and colleagues implant retinal cells deep into the brain. The cells are placed on gelatin beads. The cells wrap themselves around the beads and form a ball. "The cells themselves stay on the beads, so they don't go migrating around the brain like stem cells do. They stay right where they're put, and they produce the drug -- the idea is to smooth out the delivery of the medication. In other words, part of this fluctuation between freezing and excess movement is that the drug levels in the brain fluctuate up and down. So by keeping it more level, you increase the patient's performance," Bakay said. After one year, the six patients who were initially transplanted improved their motor behavior by up to 50 percent. "That's a huge amount of improvement, and at two years they had maintained it at about 41 percent," Bakay said. Patients also improved in their activity of daily living and in terms of their mental outlook. The study is currently ongoing. There will be a total of 64 patients enrolled. Watch the video of this story: ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn