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CHANGING THE WAY DOCTORS VIEW MULTIPLE SCLEROSIS Cleveland Clinic report in New England Journal of Medicine says MS cuts nerve fibers, resulting in irreversible neurological impairment
A Cleveland Clinic study published today in the New England Journal of Medicine concludes that multiple sclerosis not only destroys the protective sheath around nerves, but also cuts nerve fibers.
Such a finding suggests MS may be more similar to diseases that cause irreversible neurological impairment, such as Parkinson's disease or amyotrophic lateral sclerosis (ALS). However, this knowledge also provides hope that new therapies can be developed to benefit patients in the early stages of MS.
"If you don't know what is precisely wrong, you cannot design adequate therapies. This study gives us a better understanding of multiple sclerosis and ultimately could lead to new therapies for patients," said Richard Rudick, M.D., director of the Cleveland Clinic's Mellen Center, one of the largest comprehensive programs in the country for research and the treatment of multiple sclerosis.
Traditionally, multiple sclerosis has been viewed as a disease that destroys myelin, the protective coating surrounding nerves. As the myelin is eroded, patients display symptoms typically associated with MS, such as numbness or weakness of the limbs, tremor and involuntary eye movement. As the myelin is replenished, the symptoms subside. However, the Cleveland Clinic's study indicates that MS also transects nerve fibers. Once the nerve fiber is cut, it cannot be restored.
"If you look at the nerve fibers and the myelin as wires and insulation, MS is usually viewed as a disease that destroys the insulation. Now we are saying MS cuts the wires, too," said Bruce D. Trapp, Ph.D., chairman of the Department of Neurosciences in the Cleveland Clinic's Lerner Research Institute and the lead author of the study. "This finding puts a whole new focus on how we view the disease process of multiple sclerosis, and it should have an impact on how the disease is treated in the future."
Diseases such as ALS and Parkinson's initially go through a "silent stage" that can last for years. During this stage, neurons are being destroyed, but because the brain compensates, patients display no symptoms and typically are not diagnosed. New medications are being developed for these patients to address the destruction of the nerve fibers, but by the time the silent stage ends and the disease is diagnosed, much irreversible damage has been done.
However, because the myelin is being eroded, MS patients display symptoms and typically are diagnosed much earlier -- before a large number of nerve fibers are destroyed. "This creates the opportunity to intervene with existing or novel therapies at an early stage of the illness before significant nerve damage has developed," said Dr. Rudick.
About 350,000 Americans have been diagnosed with multiple sclerosis. It can strike at almost any age but is most common among people in their 20s. Woman are almost twice as likely to be diagnosed with MS than men.
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