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Steroids May Reverse Loss Of Myelin

CHAMPAIGN, IL -- Oct. 2, 1998 -- Steroids help to reduce inflammation, but University of Illinois scientists suggest they also could be used to reverse a loss of myelin -- a major problem in multiple sclerosis and other demyelinating diseases and injuries associated with the central and peripheral nervous systems.

Treatment of MS already includes the use of steroids, because they relieve inflammation and speed remission. The new findings -- published in September's biochemistry section of the Proceedings of the National Academy of Sciences -- indicate that the steroids dexamethasone and progesterone actually signal the initiation and dramatically increase the rate of myelin synthesis.

"I think this work is very important in that it helps clarify the signals that are responsible for the synthesis of myelin," said Jonah Chan, a doctoral student in the department of biochemistry and neuroscience program at the U. of I.

Myelin is a white substance made of fat and proteins that forms in a protective spiral sheath around the axon of nerve fibres. The sheath is a vital component of the body's efficient and rapid nerve-communication system. When myelin fails to form, nerve signalling breaks down, jeopardising nerve communications and leading to altered sensations and a multitude of other problems.

What causes a loss of myelin -- demyelination -- in MS cases is not known, but is believed to be the result of an abnormal immune response to bacteria and viruses. While MS affects everyone differently, demyelination is a focal point of research around the world.

"Steroids seem to be very important in regulating the initiation and synthesis," said Michael Glaser, professor of biochemistry and lead investigator of the project. "They had been implicated as having a role in the overall process, but not for enhancing the actual synthesis. It is our hope that this line of work will lead to a line of treatment for nerve injuries and demyelinating diseases."

Last year in the Journal of Neuroscience Research, Glaser's team reported the first technique for observing the continual synthesis of myelin by Schwann cells around axons of neurons. In their new work, researchers added various forms of steroids and antagonists, observing their effects on the cells under a fluorescence digital-imaging microscope. When dexamethasone and progesterone were added, individually, to the tissue culture cells, the initiation of myelin production began 24 hours earlier than it did under control conditions, and the peak rate of myelin formation increased by more than 2-fold.

Their findings provided the first live look at the signals initiating myelin formation in live cells, Glaser said. Before his new assay was developed, researchers were restricted to simply observing myelin at a single stage of production.

Thanks to The Doctor's Guide to the Internet™ for the article


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