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Friday, June 15, 2007 Cool stem cell development Parkinson's in primates has been successfully treated using embryonic stem cells. But that's just one big development. Their results mark the first successful stem cell therapy for Parkinson's in primates. The big news, however, is not simply that the treatment worked, but how it worked: by rescuing and rejuvenating, rather than replacing, diseased cells. "It's a different principle of stem cell action from what everyone's thinking about," said Richard Sidman, a Harvard Medical School neuroscientist and co-author of the research. The study is a landmark, both for treating Parkinson's disease and for highlighting a new therapeutic approach to stem cells. While most scientists are struggling to change stem cells into the types of cells they need -- neurons, insulin-producing cells, heart cells, etc. -- the new work shows that stem cells can perform the remarkable task of saving damaged cells. The findings, which will soon be published in the Proceedings of the National Academy of Sciences, show that neural stem cells have "therapeutic mechanisms other than replacement," said Cesar Borlongan, a Medical College of Georgia neurologist. Borlongan said he has observed similar effects when using stem cells to treat Parkinson's symptoms in rodents. The mechanism could provide an alternative to the tricky prospect of coaxing stem cells to take on specific functions, a process known as differentiation, and then meld seamlessly with the brain, Sidman said. "It's a lot nicer to protect a patient's own cells, because those cells are already in the brain and are wired to work the way the brain is supposed to work," Sidman said. "If you put in differentiated cells, you have to get them to connect with the other neurons and make a functional circuitry." [...] Sidman, along with Yale University's Eugene Redmond and Evan Snyder of the Burnham Institute for Medical Research, injected stem cells taken from the brains of 13-week-old aborted human fetuses into African green monkeys with damaged dopamine-producing brain cells. Dopamine is a neurotransmitter that affects motion and balance. The death of so-called dopaminergic neurons has been linked to Parkinson's disease, an incurable neurodegenerative disorder that affects about one million Americans. At the time of the injections, the monkeys couldn't feed themselves or walk without assistance, and alternated between periods of absolute stillness and uncontrollable tremors. Two months after the treatment, they were able to walk and eat. The tremors had disappeared. "The behavioral improvement was very impressive," Langston said. Four months after the injection, the effects started to wear off. Sidman's team sacrificed the monkeys and looked into their brains to see what had happened. They figured the stem cells, which when injected were on their way to becoming different types of brain cells but hadn't yet specialized, would replace the monkey's own neurons. That's how stem cells are expected to work. But far from turning into a mass of brand-new dopamine-producing neurons, most of the cells clustered around existing neurons, protecting them from further damage and rejuvenating those that had deteriorated. This has a long way to go, there still are a lot of unknowns and potential drawbacks, but the results are pretty impressive. To repeat: Parkinson's was successfully treated in primates. That's a high degree of likelihood we'd get the exact same results in humans. As well as that, these embryonic stem cells showed a possible new general mechanism for medical treatments via rejuvenation. The two most commonly cited examples for potential treatment via stem cells are Parkinson's and diabetes. We know diabetes can be treated/cured in humans (believe they'd qualify it as treatment in most cases, but I'm not sure); we now know Parkinson's likely can too due to these results. How is it possible that people can reject federal funding for this science with these very, very, slow but terrific early developments? It's simply unbelievable. Written by Callandor at 11:21 PM 0 comments Links to this post Rayilyn Brown Board Member AZNPF Arizona Chapter National Parkinson's Foundation [log in to unmask] ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn