Tuesday, October 05, 2010
ScienceDaily (Oct. 3, 2010) — "Unlike nerves of the spinal cord, the peripheral nerves that connect our limbs and organs to the central nervous system have an astonishing ability to regenerate themselves after injury. Now, a new report in the October 1st issue of Cell, a Cell Press publication, offers new insight into how that healing process works.
"We know a lot about how various cell types differentiate during development, but after a serious injury like an amputation, nerves must re-grow," said Allison Lloyd of University College London. "They need a new mechanism to do that because the developmental signals aren't there."
That kind of regrowth isn't easy to pull off. Peripheral nerves are long cells; their nucleus is in the spinal cord and the axons that extend from them and relay nerve messages can reach all the way down a leg. "When a nerve gets cut, all the axons downstream degenerate," Lloyd said. Regrowth requires that the two ends somehow find their way back to each other through damaged tissue.
Scientists knew that Schwann cells were important to that process. Those cells are found wrapped around axons, where under normal circumstances they are rather "quiet" cells. All of that changes when an injury occurs; those Schwann cells de-differentiate back to a stem-cell-like state and play an important role in bridging the gap to repair damaged neurons."
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