X-Message-Number: 14786 From: "Jan Coetzee" <> Subject: Gene Therapy Date: Thu, 26 Oct 2000 17:37:38 -0400 This is a multi-part message in MIME format. ------=_NextPart_000_010F_01C03F73.6F798E00 Content-Type: text/plain; charset="iso-8859-1" Gene Therapy May Help in Parkinson's, Study Finds By Maggie Fox, Health and Science Correspondent WASHINGTON (Reuters) - A gene therapy treatment using a gutted version of the AIDS virus and a protein that nourishes brain cells may help prevent the onset of Parkinson's in patients with early symptoms of the disease, researchers said on Thursday. Tests done in monkeys suggest that it may be possible to save the brain cells lost in Parkinson's, the international team of researchers reports in Friday's issue of the journal Science. ``We were able to completely reverse motor deficits in these animals and also completely prevent the destruction of the substantia nigra (the part of the brain damaged in Parkinson's),'' Jeffrey Kordower, a neurologist at Rush Presbyterian-St. Luke's Medical Centre in Chicago who led the study, said in a telephone interview. Parkinson's, which affects an estimated 500,000 people in the United States alone, is a progressive and incurable disease that involves the destruction of brain cells that produce dopamine, an important message-carrying chemical linked with movement. Patients start out with tremors or a strange sort of freezing, and can become paralyzed and die. There is no cure and treatments can delay the disease for a while but eventually stop working. Kordower's team. including scientists at the Swiss Federal Institute of Technology in Lausanne, Switzerland and in France, wanted to see if there was some way to stop this. They used two monkey ``models'' of Parkinson's -- old monkeys whose brains have started to degenerate, and monkeys with a Parkinson's-like disease caused by chemically damaging the brain. ``Aged monkeys lose dopamine,'' Kordower said. ``That models the earliest cellular changes in patients with Parkinson's.'' Monkeys with the damaged brains show symptoms of later Parkinson's. They are taught to do tasks -- such as getting fruit out of a box -- that can easily be measured so scientists can monitor the changes caused by the damage. The researchers gutted the HIV virus to make it harmless. HIV attaches to cells and pumps its genetic material inside, so it is a good vector, or carrier, of gene therapy. Inside the hollowed-out virus they put the gene for glial-derived neurotrophic factor (GDNF), a protein shown in previous studies to affect the dopamine-producing neurons. Then they injected this combination, or a virus carrying a dummy gene, into the brains of their monkeys. Brain Cells Work Better After Injections In both cases, the gene therapy made the dopamine-producing cells work better. It lasted for months, and the effects could be clearly seen in the tasks done by the second group of monkeys, Kordower said. ``We anticipate that we can get long-term benefit from a single treatment,'' said Kordower, who presented his findings to a meeting at the National Institutes of Health this week. It may even work too well and need to be toned down. ``This is the most potent gene therapy delivery system seen in Parkinson's,'' Kordower said. ``In fact, it is so potent our main concern is it could be too potent. What we need to do before we can go into humans is to have a gene that we could control.'' Kordower hopes to do this by using a common method -- engineering the gene so that it can be turned on and off with the use of the antibiotic tetracycline. ``So if we put it into the brain of a patient and things go bad, there is too much dopamine, we can shut it off,'' he said. Kordower does not think the method will work for patients with advanced Parkinson's, because they have already lost too many brain cells. Experimental treatments for such patients include injections of brain cells from human and pig embryos. Foster City, California-based Cell Genesys Inc. owns the patent for the virus vector used in the experiment and Amgen Inc. owns the patent for the GDNF, Kordower said. ------=_NextPart_000_010F_01C03F73.6F798E00 Content-Type: text/html; [ AUTOMATICALLY SKIPPING HTML ENCODING! ] Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=14786