FRIDAY, March 19, 2004 (HealthDayNews) -- There are no clear or easy answers when it comes to multiple sclerosis.
The 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.
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.
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 January 2004 issue of Neurology. "A lot of patients do very, very well, and the reason is that they have protective responses. 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. 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."
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 Antegren showed promising results. Another study found that Zocor, 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.
More information
The National Multiple Sclerosis Society has more on research and on treatments for MS.
