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FROM: Sign On San Diego.com http://www.signonsandiego.com/news/science/20041025-9999-1m25stem.html Scientists discuss uses, potential of stem cells Tissue-regeneration progress reported By Bruce Lieberman UNION-TRIBUNE STAFF WRITER October 25, 2004 Injured spinal cords, Parkinson's disease and brain tumors – all are targets for the regenerative power of stem cells, neuroscientists said yesterday. The researchers, joining 30,000 of their colleagues in San Diego this week for the largest annual meeting of neuroscientists in the world, spoke of the latest studies to manipulate stem cells to help restore health. The scientists discussed potential approaches using both embryonic stem cells, which can develop into every other cell in the body, and adult stem cells, the storehouse of replacement cells identified in several tissues and organs. The briefing yesterday came a little more than a week before California voters determine the fate of Proposition 71, an initiative that would raise $3 billion in state bond proceeds to fund research grants. President Bush has restricted funding to a small number of stem cell lineages available as of Aug. 9, 2001, saying the destruction of further embryos would be tantamount to killing human lives. Scientists argue that they need access to new embryos, many of them discarded each year by fertility clinics, to study their full potential. Yesterday, a handful of researchers at the Society for Neuroscience meeting spoke about areas that show the potential power of stem cells to fight injury and disease. Hans Keirstead from UC Irvine reported that his lab was able to coax human embryonic stem cells into developing into oligodendrocytes, a type of cell in the brain that forms myelin, a fatty substance that insulates the long, wire-like extensions of nerve cells, called axons. The myelin sheaths, which are also destroyed in people suffering from multiple sclerosis, allow electrical signals to travel between nerve cells in the brain and body. After much effort to purify oligodendrocytes in the lab, Keirstead transplanted the cells into rats seven days after their spinal cords had been surgically severed. The transplanted oligodendrocytes survived, migrated to the proper place in the animals' damaged nervous system and restored myelin to the axons that had lost it after injury, Keirstead said. As a result, the animals were able to support their weight, re-animate their tails and gain some walking ability. "It's not perfect," said Keirstead. "They're not playing soccer, but they're doing extremely well." In other work, University of Wisconsin researcher Clive N. Svendsen reported that neural stem cells taken from fetal tissue can be quickly multiplied in the lab. The cells, then engineered to produce a naturally-occurring molecule called a growth factor, glial-derived neurotrophic factor or GDNF, were transplanted directly into the brains of rats. Once inside the brain, the stem cells producing GDNF led to increased levels of dopamine, a key neurotransmitter lost in Parkinson's. The federal government wants to make sure that researchers can control the release of GDNF in the brain. If they can, then clinical trials could begin in coming years, he said. Evan Snyder, a stem cell biologist at The Burnham Institute in La Jolla, said he is studying how stem cells transplanted into the brain appear to attack tumors there. In mice studies, Snyder has found that neural stem cells grown in the lab and transplanted into mice migrated from one side of the brain to the other, homing in on, surrounding and infiltrating tumors. They even attack the blood vessels that feed them, he said. Exactly why, or how, the stem cells find and attack brain tumors is uncertain, but Snyder said the cells could be genetically engineered to express proteins lethal to tumor cells. "I have a lot of confidence that this will have an impact," Snyder said of his preliminary work with animals. "It's not a cure, but I think it could extend life." ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn