CHAMPAIGN, Ill. -- 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 R. 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 fibers. The sheath is a
vital component of the body's efficient and rapid
nerve-communication system. When myelin fails to form, nerve signaling
breaks down, jeopardizing 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.
The PNAS paper was written by Chan, Glaser and Lornie J. Phillips II, a
Howard Hughes Medical Institute predoctoral fellow. The research is
supported by the Multiple Sclerosis Society.
Editor's Note: The original news release can be found at
http://www.admin.uiuc.edu/NB/98.10/mstip.html