Researchers
Make Progress In Finding Ways To Treat MS
March Is National
Multiple Sclerosis Education and Awareness Month
There are no clear or easy answers when
it comes to multiple sclerosis (MS).
MS, a central nervous system disease,
is one of the most common neurological disorders among young adults.
According to the National Multiple
Sclerosis Society, about 400,000 Americans and 2.5 million
people worldwide suffer from the disease, more often women than men.
Consider the following statistics on MS, compiled by
the National Center for Health Statistics (NCHS) of
the Centers for Disease Control and Prevention (CDC):
-
In 1999 to 2000, there were approximately 700,000
visits to a physician each year that included a diagnosis of multiple
sclerosis.
-
In 1999 to 2000, 24,000 annual hospitalizations
listed multiple sclerosis as the first diagnosis. Nearly 63,000
other hospitalizations listed it as an additional diagnosis.
-
Females accounted
for 75 percent of all hospitalizations that mentioned MS.
The diagnosis of MS is most often made
when the person is young, between the ages of 20 and 30. This is exactly
the time many men and women are planning marriage, contemplating children,
and establishing careers.
No one knows what causes MS, for which
there is no cure, although promising treatments are under review. But
the likely cause appears to be a combination of genetics and environmental
factors, and involves an immune system gone awry.
"We believe it is an autoimmune disease
where the immune system is targeting its own body," says Patricia O'Looney,
director of biomedical research at the National Multiple Sclerosis
Society in New York City.
While symptoms of MS can include numbness
or weakness in the arms or legs, unsteady gait and blurred vision, no
two people experience the disease the same way.
"One year the person is fine with or without
treatment and the next year they have an exacerbation, with or without
treatment," O'Looney says. "It's very difficult."
The progression of the disease is generally
not a steady one, but involves exacerbations - or flare-ups - punctuated
by periods of stability. No one knows what triggers an exacerbation.
But as the nation marks National
Multiple Sclerosis Education and Awareness Month in March,
the news is not all bad.
Patient
Experiences Vary from Year to Year
For instance, researchers at the Mayo Clinic
in Rochester, Minn., followed all residents with MS in Olmsted County,
Minn., from 1991 to 2001.
They found that only about one-third have
severe disease, with about 70 percent reporting only a mild increase
in disability over the 10-year time span.
"I think that's very, very comforting to
patients with MS," says Dr. Moses Rodriguez, senior author of the research,
which appeared in the medical journal Neurology.
"A lot of patients do very, very well,
and the reason is that they have protective responses," Dr. Rodriguez
says. "If we could figure out more about what makes those patients do
well, we'd have an important clue. This tells us this is a disease we
can live with."
Until that is determined, however, existing
treatments serve mainly to limit the number, duration, or severity of
exacerbations, but they don't eliminate attacks. Other treatments try
to turn off the immune system one way or another.
None of these treatments, obviously, constitutes
a cure. Research today is looking toward a cure and toward more successful
therapies.
"The direction of clinical treatment today
is to find a better treatment and most likely it will be a combination
treatment," O'Looney says.
"The available therapies that we have give
us a 30 to 35 percent reduction in our measures of relapse rate and
disability," adds Dr. Fred Lublin, director of the Corinne Goldsmith
Dickinson Center for Multiple Sclerosis at Mount Sinai Medical Center
in New York City.
"Ten years ago, we didn't have any therapies,"
Dr. Lublin says. "We're delighted to have those, but we now need to
move forward and do better. One way would be to combine therapies that
have different putative mechanisms of action."
Immune
System Studied
Dr. Lublin's center recently received a
$30 million National Institutes of Health grant to
look at the combined effect of the drugs interferon beta 1a and glatiramer
acetate on immune functioning.
Experts do know that MS involves the destruction
of myelin, or the protective sheath of fatty tissue that surrounds nerve
fibers and helps them conduct electrical impulses.
More recently, researchers have discovered
that the axon or nerve cell is also damaged, which makes sense. Because
it has lost its protective covering, the axon becomes vulnerable to
attack from the body's own immune cells.
"There is an immediate need to not only
control the immune system but to try to find ways to repair myelin so
as to protect the axons," O'Looney says.
The big challenge is figuring out how to
replace myelin that is being destroyed. Scientists are grappling with
basic questions such as: Can you stimulate cells that make myelin? Can
you stimulate them to make more using growth factors?
The other problem is that the myelin damage
is not just in one location, but several.
"These are troubling questions for researchers
to try to identify which cells to use to repair myelin," O'Looney says.
"Can it repair cells? Does it restore function? How do you repair damage
in all areas?"
Last year saw a number of other research
gains. An early phase clinical trial of the monoclonal antibody AntegrenTM showed
promising results. Another study found that ZocorTM,
a cholesterol-lowering drug, reduced the number of new brain lesions
in a small group of people.
Other studies suggest that smoking may
somehow increase susceptibility to MS, and that sun exposure from age
six to 15 may actually be associated with a lower risk for MS. This
last point may have to do with increased production of vitamin D, which
occurs in the body as a result of sun exposure.
Always consult your physician for more
information.
|
March 2004
Researchers
Make Progress In Finding Ways To Treat MS
Patient
Experiences Vary from Year to Year
Immune
System Studied
MS
Expert Talks About A Promising Approach
Online
Resources
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MS
Expert Talks About A Promising Approach
When
Dr. Moses Rodriguez started researching multiple sclerosis two decades
ago, the prevailing wisdom was that repairing the nervous system was
impossible.
Now
he knows that's not true.
Dr. Rodriguez, a professor of neurology and immunology at the Mayo Clinic
in Rochester, Minn., was intrigued by MS patients who had devastating
attacks and then, one year later, seemed to be dramatically better.
"We
hadn't done anything," he says. "The body had been able to do something
to induce repair."
In
the intervening years, Dr. Rodriguez has been able to identify a whole
series of antibodies that were able to perform dramatic repairs in animal
tests of MS.
"We
have been able to show definitely that we can get very significant repair
of the nervous system," he says.
These
antibodies are part of the body's natural defense system.
"They
are present in all of us and are playing a role in repairing our bodies,"
Dr. Rodriguez explains. In people with MS, however, they are present
at only low levels.
"It's
very exciting, because theoretically it should be very nontoxic," Dr.
Rodriguez says. "You're giving back. It's a normal, very natural, reparative
kind of approach. Most approaches in MS have been destructive. People
are trying to get rid of T cells or immunosuppress people or take away
things."
Now
Dr. Rodriguez and his colleagues have identified antibodies in humans
and have unraveled the complete molecular sequence, meaning they can
manufacture them.
In
fact, Dr. Rodriguez is planning clinical trials in collaboration with
Acorda Therapeutics.
"The
company is committed to taking this forward; I think it's going to happen
relatively soon," Dr. Rodriguez says.
Dr.
Rodriguez has departed from conventional MS research in another way
as well.
Traditionally,
experts have focused on the myelin sheath, which insulates the axon
or nerve cell.
"What
we're finding is the real problem is in the neuron or axon, not the
myelin," Dr. Rodriguez says. "We may be concentrating on the wrong thing.
Once we get over that big step, we may be able to find more effective
therapies."
Without
myelin, the axon is like "a tree without bark," Dr. Rodriguez explains.
"All of a sudden, anything can get into it and the axon is going to
die. One of the things you've got to do is protect those axons from
dying."
Killer
T-cells, which are part of the body's immune system and the most common
T cells in the brains of MS patients, appear to be killing the axons.
When
Dr. Rodriguez and his colleagues deleted killer T-cells in animal models,
the animals showed no neurological problems.
"That
shows that killer T cells are the bad guys," he says. "If we can get
rid of killer T-cells, we can do a lot."
Always
consult your physician for more information.
Online
Resources
Centers
for Disease Control and Prevention (CDC)
Multiple
Sclerosis Association of America
National
Institute of Neurological Disorders and Stroke
National
Institutes of Health (NIH)
National
Multiple Sclerosis Society
US
Department of Heath and Human Services
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