Pregnancy hormone key to repairing nerve
cell damage
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Medical Update Memo
February 22, 2007
SUMMARY
University of Calgary researchers have shown
that a pregnancy-related hormone encourages
the spontaneous rebuilding of myelin, the
protective coating around nerve cells that
is attacked in multiple sclerosis. The results
of a two year study have been published in
the February 21 edition of The Journal
of Neuroscience.
The study was partially funded by the Multiple
Sclerosis Society of Canada.
DETAILS
In the February 21 issue of The Journal
of Neuroscience (2007 27: 1812-1823), a team
of researchers from the University of Calgary’s
Faculty of Medicine reports that a study
conducted on mice found that the hormone
prolactin encourages the spontaneous production
of myelin, the fatty substance that coats
nerve cells and plays a critical role in
transmitting messages in the central nervous
system. The study is the first to determine
that prolactin, which increases in the body
during pregnancy, is directly responsible
for the formation of new myelin in the brains
and spinal cords of pregnant mice. Further,
when non-pregnant mice with MS-like lesions
were injected with prolactin, their myelin
was also repaired.
The study compared pregnant and virgin female
mice of the same age and found that pregnant
mice had twice as many myelin-producing cells,
called oligodendrocytes, and continued to generate
new ones during pregnancy. By chemically destroying
myelin around nerve cells, the researchers
found that pregnant mice had twice as much
new myelin two weeks following the damage as
virgin mice and that introducing prolactin
mimicked the effects of pregnancy on myelin
production and repair in mice that weren’t
pregnant.
The research was based on evidence that MS,
which is more common in women than men, goes
into remission when women become pregnant. “It
is thought that during pregnancy, women’s
immune systems no longer destroyed the myelin,” said
Dr. Weiss, director of the Hotchkiss Brain
Institute and senior author of the study. “However,
no previous study has tested whether pregnancy
actually results in the production of new myelin,
which may lead to improvement of symptoms.” The
paper’s findings represent the first
example of a natural, biological mechanism
that produces new myelin in the adult brain
and spinal cord and identifies prolactin as
a potential therapeutic substance for future
testing in people with MS.
Subsequent tests of prolactin in animal models
of MS will be required before testing of
prolactin on humans can take place, but
MS researchers are hopeful human trials can
take place within the next several years.
“This discovery has the potential to
take MS therapy a step further than current
treatments that stabilize the disease in its
early stages. By promoting repair, which is
the goal of prolactin therapy, we have hope
of actually improving symptoms in people with
MS,” says Dr. Luanne Metz, director of
the Calgary MS Clinic in the Department of
Clinical Neurosciences, University of Calgary
and Calgary Health Region.
“The results of this study should be
well received by people living with MS today,” said
Dr. William McIlroy, national medical advisor
for the Multiple Sclerosis Society of Canada. “It
represents a new insight of how we might be
able to reverse some of the effects of the
disease and improve the quality of life for
those who live under its influence.”
The study was funded by the Multiple Sclerosis
Society of Canada and the Canadian Institutes
of Health Research with the support of the
Alberta Heritage Foundation for Medical Research
and the Stem Cell Network.
ASK MS Information System Code: 2.6.3.c
National Research Department
National Marketing and Communications Department
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