MS and Gray Matter

Multiple Sclerosis may originate in cortex

(RxWiki News) Multiple sclerosis manifests in a wide range of symptoms, from difficulty with balance to fatigue and vision problems. These problems all originate in the brain, but how?

New research has found that multiple sclerosis (MS) progresses through the brain by taking a different path than previously thought. The theory was that MS begins in the myelin deep inside the brain, the sheath that covers and protects the nerve cells.

But it may be opposite, with the disease progressing from the outer layers of the brain in. Understanding how the disease progresses can help inform treatment and drug development.

"Ask your doctor about current treatment options for MS."

Scientists do not fully understand the underlying causes of MS. But it's considered an autoimmune disease in which the body attacks itself. By damaging myelin, MS disrupts the communication between nerve cells and the rest of the body, leading to worsening and irreversible dysfunction.

The study was led by Richard Ransohoff, M.D., Director of the Neuroinflammation Research Center of the Department of Neurosciences at Cleveland Clinic's Lerner Research Institute, and Claudia Lucchinetti, M.D., of the Mayo Clinic's Department of Neurology.

The study marks the first time that early multiple sclerosis brain lesions were examined in the cerebral cortex, or the outer portion of the front of the brain. The cerebral cortex is associated with memory, attention, thought, and awareness, among other functions. It's also called gray matter.

The researchers examined 563 brain biopsies, or pieces of brain tissue, which had received a diagnosis of inflammatory demyelinating disease of the central nervous system. Of the 138 biopsies that had enough gray matter to study, 77 had follow-up data. 75 percent of these cases went on to develop full blown MS.

They found that in the early stages of MS, it was common to see cortical demyelination, or damage to the myelin in the gray matter, in other words. These lesions were inflammatory in nature.

That led to speculation about how MS might progress from these early stages. In the study, the authors write that myelin-laden macrophages, a type of immune cell, move from the cortex to the cerebrospinal fluid, and access the cervical lymph nodes to propagate the disease process.

Dr. Ransohoff said that the take-home message for patients is that they may have discovered an “entirely new concept” of how MS starts.

The study was published in the December 8, 2011 issue of The New England Journal of Medicine.

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Review Date: 
December 11, 2011