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International Physician Update
| NEUROREGENERATION |
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| January 2005 |
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Stem Cells Jump First Hurdle
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| Doug Kerr studies rodents’ motor neurons to find cures for neurodegenerative diseases. |
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Like Humphrey Bogart and Lauren Bacall, stem cells and the broad neuro- degenerative diseases like ALS appear made for each other. Yet, so far—a la Hollywood—the relationship has been a construct of the imagination.
Most neurological stem cell work has focused on Parkinson’s or stroke, where damage in the brain is both clear and contained. Diseases with widely spread pathology—ALS, MS or Alzheimer’s—still wait.
But now, in a study that’s reversed some of the ravages of more neuron disease, at least in animals, neurologist Douglas Kerr and his Hopkins co-researchers suggest stem cells may prove more broadly useful. Kerr recently created a rat model of spinal motor atrophy (SMA) using Sinbis virus—a potent one that destroys rodents’ motor neurons. True to that neurological disease, the rats lost lower motor neurons, dragging their paralyzed lower trunks and hind legs behind otherwise normal bodies.
The researchers then injected a modified version of human embryonic stem cells—cultured by Hopkins’ stem cell pioneer John Gearhart—into the spinal fluid of the paralyzed animals. Three months later, most of the injected rats could flex their hips and place feet firmly enough to bear weight. A few of the rats could hobble.
“As thrilling as that was, the most dramatic finding,” says Kerr, “was proof that stem cells migrated to the ventral horn of the spinal cord, exactly where neurons had died.” Further, the cells displayed molecular nerve cell markers and sent axons outward. “They even look like motor neurons.”
Although the rats improved, Kerr believes they’ll plateau far short of normal. “To regain full movement, you’d likely have to reconstitute the entire incredible system—the thousands of axons at the spinal cord level—each with its unique destination.
But Kerr thinks nervous systems can make do with considerably less. “We may not have to replace all the original circuitry.”
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