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Center Director Discusses New Research,
Cautions Reporters at Stem Cell Symposium The results, which involve nervous system cells called astrocytes, shore up new ideas on the biology of ALS and support the first very early steps on a novel therapeutic path. Rothstein began his talk with a description of ALS, then discussed use of animal models such as the SOD1 mice and rats----both containing the same defective human gene as is found in some inherited forms of the disease. He explained that a body of new work by researchers at the Center and elsewhere shows that not only are motor neuron cells abnormal in ALS, but also neighboring cells called astrocytes undergo changes even before symptoms appear in the animals. Also he cited Center studies that involve mice engineered to have cells with the inherited ALS defect and normal cells next to each other in the same mouse. The behavior of cells in these "chimeric" animals is revealing, Rothstein said, and may provide a basis for a stem cell approach to therapy. If astrocytes are healthy, he said, neighboring motor neuron cells' decline is either much less likely or is far slower, even if the motor cells contain the defect. In the reverse situation, mutant astrocytes are able to pass their toxic properties on to their motor neuron neighbors. "ALS, then, isn't just a disease of motor neurons," Rothstein said. "It's also a disease of the cells that surround motor neurons, such as astrocytes. And if you think of stem cell therapy, it's not just the motor neurons you want to fix. It's also the astrocytes." Further, he said, Center studies are showing how this might work in lab situations. Cultures of motor neurons that contain a defect typical of inherited ALS, where the cells are in danger of dying, can be protected when researchers add stem cells that produce "improved" astrocytes to the cultures. The stem cells contain an added gene that makes their "offspring" astrocytes especially neuroprotective. * * * * In the last part of his presentation, Rothstein cautioned science writers against saying stem cell therapy is around the corner. "My patients ask, 'Why can't I have stem cells now?' and I tell them we still have too many questions: What kind do we use? How many do we put into patients-a thousand? a million? How often do we add them? These are practical issues of therapeutics." And how do you introduce the cells? Rothstein said this is a great unknown. "You just can't stick them in blood or the skin, as we hear some unscrupulous people are trying. The body has a blood-brain barrier that naturally keeps cells from entering the central nervous system, where they'd presumably have any effect on ALS patients." He also raised important safety issues. Some stem cells under certain conditions could form tumors. And what about immune reactions? The body could attack foreign cells and cause inflammation. The spinal cord, Rothstein explained, won't tolerate inflammation. The swelling and pressure that come with inflammation in that narrow organ could cause severe pain or paralysis, he said. "We can see that there's promise, there's potential with stem cells," Rothstein told the reporters. "But we need to get answers, we need to do things in the proper order. That doesn't mean we're not being proactive. We know patients are dying. But we need to make sure they'll be helped in the future."
The Center for ALS Research at Johns Hopkins is a collaborative effort by some of the best ALS and non-ALS scientists to aggressively and rapidly develop new treatments and find a cure for ALS, also know as Lou Gehrig's disease. It's the only institution of its kind dedicated solely to the disease. Research conducted by the Center is meant to translate from bench to bedside in a expedited time frame. Center scientists from institutions around the world have made some of the most important discoveries in ALS, leading to advances in understanding and treatment of the disease. The nature of ALS shapes the Center's aggressive, results-oriented scientific approach. ALS is a divesting, progressive neuromuscular disease that causes complete paralysis and loss of function-including the ability to eat, speak, and breathe-and eventually, death. ALS progresses quickly and is not curable. Most patients die within five years of diagnosis. |
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