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Researchers determine that multiple sclerosis and diabetes are closely
linked diseases
March
21, 2001
TORONTO, March 20 /CNW/ via NewsEdge Corporation
A team of researchers led
by Hospital for Sick Children (HSC) senior scientist Michael
Dosch has determined that multiple sclerosis and type I
(juvenile) diabetes mellitus are far more closely linked than
previously thought, including the role cow milk protein plays as
a risk factor in the development of both diseases for people who
are genetically susceptible. This research is published in
recent issues of The Journal of Immunology (April 1 and February
15, 2001).
Multiple
sclerosis (MS) and type I diabetes mellitus are autoimmune
disorders, where the body's immune system attacks its own
tissue. The diseases are entirely different clinically, but have
nearly identical ethnic and geographic distribution, genetic
similarities, and, as is now known, shared environmental risk
factors.
In
a collaboration between The Hospital For Sick Children, St.
Michael's Hospital and the Pittsburgh Children's Hospital, Dr.
Dosch's laboratory discovered a high degree of similarity in the
autoimmunity of MS and diabetes patients, and that a widely used
mouse model for diabetes could also develop an MS-like disease.
"Much
to our surprise, we found that immunologically, type I diabetes
and multiple sclerosis are almost the same - in a test tube you
can barely tell the two diseases apart," said Dr. Dosch,
the study's principal investigator, a senior scientist in the
HSC Research Institute, and a professor of Pediatrics and
Immunology at the University of Toronto (U of T). "We found
that the autoimmunity was not specific to the organ system
affected by the disease. Previously it was thought that in MS
autoimmunity would develop in the central nervous system, and in
diabetes it would only be found in the pancreas. We found that
both tissues are targeted in each disease."
In
diabetes and MS, there is a long, drawn-out period of silent
disease years before the appearance of symptoms and diagnosis of
the disease. In diabetes, it is this "pre-diabetes"
phase that is targeted by interventions to stop the development
of the full-blown disease. Similar efforts are planned for
individuals at high risk for MS.
"We
are planning a large international study with centers in Canada
and the US to test the possibility of interventions during the
pre-MS phase," added Dr. Dosch.
One
of the major environmental risk factors for diabetes is exposure
to cow milk protein. Based on the role of cow milk protein as a
risk factor in the development of type I diabetes, an
international global diabetes prevention trial called TRIGR -
Trial to Reduce Insulin-dependent diabetes in the Genetically at
Risk - is expected to begin later this year, with Dr. Dosch as
the trial's basic science chair. In the first step to test just
how far the similarities between MS and diabetes go, the study's
researchers looked for signs of abnormal immunity to cow milk in
MS patients. Such abnormalities were indeed found in most
patients, suggesting that similar processes may contribute to
both diseases. If confirmed in a larger and prospective family
study, it may become possible to design dietary means to
influence the course of MS as well as diabetes.
"The
similarities found between MS and type I diabetes will open new
avenues of research. Our next focus will be to study MS family
members for signs of early MS," said Dr. Paul O'Connor,
head of the MS clinic at St. Michael's Hospital, a co-author of
the study and Associate Professor of Neurology at U of T.
Other
collaborators on this research were: Shawn Winer, Igor
Astsaturov, Roy K. Cheung, Lakshman Gunaratnam, Denise D. Wood
and Professor Mario Moscarello, all from the HSC Research
Institute; Colin McKerlie, Sunnybrook and Women's Health
Sciences Center and the University of Toronto; and Professor
Dorothy J. Becker, Children's Hospital of Pittsburgh and the
University of Pittsburgh.
Funding
for this research was provided by the Canadian Institutes of
Health Research, the Juvenile Diabetes Foundation, the Canadian
Diabetes Association, the US National Institutes of Health and
the Renziehausen Fund.
For
further information: please contact: Laura Greer, Public
Affairs, The Hospital for Sick Children, (416) 813-5046,
laura.greer@sickkids.ca; Tracy MacIsaac, Media Relations, St.
Michael's Hospital, (416) 864-5047, macisaact@smh.toronto.on.ca
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