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I heard about this on Air America today. Good news for someone, but I think I'm too old, Ray ----- Original Message ----- From: "Peggy Willocks" <[log in to unmask]> To: <[log in to unmask]> Sent: Tuesday, June 20, 2006 10:36 PM Subject: New hope with stem cells/GDNF >A must-read! > > Peggy > > http://www.forbes.com/forbeslife/health/feeds/hscout/2006/06/20/hscout533366 > .html > Stem-Cell Therapy Restores Movement in Paralyzed Mice > 06.20.06, 12:00 AM ET > TUESDAY, June 20 (HealthDay News) -- In what experts are describing as a > major advance, scientists have used embryonic stem cells to form new, > functional nerve cell connections in formerly paralyzed mice that > effectively restored the animals' limb movement. > > While success in humans remains a distant goal, the achievement is "proof > of > principle" that stem-cell grafts such as these might someday be used to > treat spinal cord injury, ALS (Lou Gehrig's disease), Parkinson's disease > and other crippling neurological conditions, one expert said. > > "This is something that we've been looking for for 30 years," said Naomi > Kleitman, program director of the Extramural Research Program at the U.S. > National Institute of Neurological Disorders and Stroke. > > Kleitman was not involved in the study, but her office helped fund the > research. She called the finding "exciting, because it proves the > principle > that with the right combination, we can coax [nerve] cells out, and now we > know what to build on." > > The findings will be published Monday in the journal Annals of > Neurology. > > Numerous studies have come out over the past few years showing that > embryonic stem cells can form nerve cells in areas of the spinal cord > damaged by injury or disease. But getting these motor neurons to make > functional connections to muscle has been a frustrating roadblock. > > "In the simplest [neuronal] relay, a brain cell talks to the motor neuron > in > the spinal cord and says, 'Move that muscle,' " Kleitman explained. > "Then, the motor neuron reaches out of the spinal cord to the muscle using > these long fibers called axons. They communicate with the muscle, send an > impulse, and the muscle contracts." > > But this seemingly simple network relies on a complex partnership of > growth > factors and signaling chemicals -- each vital to the process. So, research > aimed at deciphering these players and their connections has continued. > > "It's like a detective story where if you don't put all the clues in > order, > you wind up going off in the wrong direction," Kleitman said. > > The new study was conducted by a team at Johns Hopkins University School > of > Medicine, led by Dr. Douglas Kerr. His group concocted a kind of neural > "recipe" that satisfied all of the conditions needed for the successful > growth and networking of new motor neurons. > > Starting in the laboratory, they first used specific growth factors to > spur > mouse embryonic stem cells to differentiate into motor neurons. Then they > added two chemicals -- retinoic acid and sonic hedgehog protein -- to help > these new cells feel more at home in the spinal-cord environment. > > The next step was to deliver these primed cells into the spinal cords of > mice previously paralyzed by a viral infection. > But another roadblock loomed. > > "We know that there are proteins in this area that inhibit axons from > growing in adult animals," Kleitman explained. The proteins are linked to > the protective myelin sheath that coats nerve fibers. "They're part of how > we keep our nervous system from going haywire during normal function," she > said. > > To overcome this resistance, the Hopkins team added two agents -- cyclic > AMP > (cAMP) and the drug rolipram -- to the mix. According to Kleitman, these > molecules "block the 'stop sign,' so that now the axons can grow." > > But there was one more hurdle -- it's one thing to allow axons the freedom > to grow, but to grow where? "You've got pretty long distances to cover, so > one of the things you need is a 'target' that's screaming out like a neon > sign, 'Come here!' " Kleitman said. > > The Hopkins group created just such a target by applying a powerful neural > growth factor, called GDNF, to the remains of nearby, deadened sciatic > nerve > cells. The GDNF -- derived from fetal mouse neural stem cells -- > essentially > "called out" to the growing axons, urging them to make the connection. > In the end, this complex biochemical "recipe" worked, the Hopkins team > reported. > > Of the more than 4,100 new motor neurons created in one mouse's spinal > cord, > about 200 exited the cord and 120 found their way to skeletal muscle. > These > new connections looked identical under the microscope to those seen in > healthy mice, the researchers said. > What's more, 11 of the 15 treated, previously paralyzed mice began to > regain > muscle strength and function and were more mobile in their cages. > > However, this restoration of function did not occur when the researchers > left out even one of the ingredients from the mix. > According to Kerr, his team has simply tried to recreate the environment > that directs neural formation early in fetal development. > > "As adults, our cells no longer respond to early developmental cues > because > those cues are usually gone," he explained in a statement. "That's what we > believe we have changed [here]. We asked what was there when motor neurons > were born, and specifically what let motor neurons extend outward. Then we > tried to bring that environment back, in the presence of adaptable, > receptive stem cells." > > Kleitman called the work "elegant," but stressed that much more research > needs to be done before this strategy could be applied to human patients. > "To take this to a person you need to work with something larger than a > rat > leg -- that's only about an inch of [neuronal] growth," she said. > Scientists > also need to make sure that certain risks associated with stem-cell > therapy > -- most notably, increased tumor formation -- can be minimized. > > However, Kerr said his group is already engaged in a federally funded > study, > set to start this summer,that will try and replicate the mouse findings in > a > larger model -- a pig -- using human embryonic stem cells. If that effort > proves successful, FDA-approved human clinical trials might be a few years > away, the researcher said. > Kleitman said the new advance has everyone in her field optimistic. > > "We get really excited when good science leads to more good science, that > then leads in a direction that can really help people," she said. > > ---------------------------------------------------------------------- > To sign-off Parkinsn send a message to: > mailto:[log in to unmask] > In the body of the message put: signoff parkinsn ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn