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------------------------------------------------------------------------ Testicular Cells May Slow Parkinson's ------------------------------------------------------------------------ NEW YORK, Oct 02 (Reuters) -- Transplanting specialized testicular cells into the brain may help slow the progression of Parkinson's disease, experts say. Transplants of fetal brain tissue from aborted fetuses have been shown to improve Parkinson's symptoms, but raised questions about the ethics of using such tissue. Surgical procedures using Sertoli cells -- cells that help the development of sperm in the testes -- "may provide a useful alternative treatment for Parkinson's disease and other neurodegenerative disorders," according to researchers at the University of South Florida (USF) College of Medicine in Tampa. Their findings appear in this month's issue of the journal Nature Medicine. Parkinson's disease occurs when production of the neurotransmitter dopamine declines in some areas of the brain. The disease leads to problems with motor functions -- such as walking, tremor, and loss of facial expression. Treatment with the drug levodopa (L-dopa) restores motor function, at least temporarily, to many Parkinson's patients. However, the beneficial effects of the drug tend to gradually decrease over time, often rendering it ineffective after about 7 or 8 years of use. "Drugs also don't help slow the progression of disease," points out study lead author Dr. Paul Sanberg, professor and chair of neuroscience at USF. He believes slowing disease progression means preventing the Parkinson's-related death of neurons themselves. Sertoli cells may do just that. These cells are found within the testes of many animals, providing both nutrients and immunological protection to sperm. Sanberg notes that "Sertoli cells are (constantly) releasing a lot of growth factors." In experiments his team conducted on rats, Sertoli cells were injected into the brain. Sanberg relates that, once introduced, Sertoli cells began releasing "growth factors (which) are then interacting with the remaining neurons, or terminals. And they are inducing 're-sprouting' or regrowth of those terminals." These re-activated neuron terminals "then release dopamine and produce recovery of (neurological) function," he said. Human Sertoli cells, unfortunately, may be hard to come by. Sanberg explains that, after human males reach puberty, their Sertoli cells tend to bind very tightly to each other within the testes. This makes their removal from adult male humans nearly impossible. But Sanberg says a previous USF study has shown that "(pre-pubertal) pig Sertoli cells could survive in a rat brain without any anti-rejection drugs." "Normally," he says, "cross-species transplants get killed right off. But because these Sertoli provide immune protection in the testes, they also provide immune protection for themselves (in the host brain). So we envisage being able to put an animal Sertoli cell into a human, as a treatment." The technique may have much broader implications. "Because it helps in protecting cells from dying, this could be used in other disorders besides Parkinson's," Sanberg said. One of those disorders might include Alzheimer's, whose progression is also tied to brain-cell death. Sanberg says he hopes to conduct the first Sertoli transplantation on a human subject within two years. By E.J. Mundell SOURCE: Nature Medicine (1997;3(10):1129-1132) Copyright 1997 Reuters Limited. <http://www.reutershealth.com/news/rhdn/199710/1997100204.html> ------------------------------------------------------------------------