Cool News About MS

Chilling Out Relieves Symptoms and Gives New Clues About the Disease
By Neil Osterwell

Sept. 10, 2001 -- There's hot news about cool clothing for people with multiple sclerosis (MS) -- and we're not talking about the latest fashions. Researchers from the Netherlands report that the symptom relief that many MS patients experience when they wear specially designed cooling garments may be due to a temporary decrease in the body's production of the chemical nitric oxide.

The finding suggests that it may be possible to develop a drug that mimics the effects of cooling and brings at least temporary relief of symptoms to people with MS, write E.A.C. Beenakker, MD, and colleagues in the Sept. 11 issue of the journal Neurology.

"This is exciting, because it's a relatively easy treatment that brings an immediate benefit," says senior author Jacques De Keyser, MD, PhD, from the University Hospital in Groningen, Netherlands, in a written statement.

MS is a disease that attacks the outer insulation of nerve fibers, which, when healthy, is supposed to help maintain the speed of nerve impulses shuttling back and forth. About 80% of people with MS say their blurred vision, muscle weakness, balance problems, and other symptoms get worse in the summer or whenever they are exposed to high temperatures. Researchers say that this occurs because heat makes the weakened nerve impulses even weaker.

Now the Dutch investigators think they know why heat makes a bad thing worse for people with MS, and why cooling the body with icy baths, air conditioning, or special clothing provides temporary relief. It appears that when these people are overheated, the immune system releases nitric oxide, which then might be blocking the transmission of important nerve signals. This could make MS symptoms noticeably worse.

They arrived at this conclusion after studying the effects of cooling at different temperatures in five men and five women with MS. The participants were given a refrigerated head-vest garment that could be set at different temperatures. Half of the group were randomly assigned to "active cooling" with vests cooled to 7 degrees Celsius (44.6 degrees Fahrenheit) and half were assigned to "sham cooling" with vests chilled to a more moderate 26 degrees Celsius (78.8 degrees Fahrenheit).

The vest with the warmer setting still feels cold to the touch because it is about 20 degrees lower than body temperature. But its actual cooling effect on the body is only minimal. This means that participants would not be able to tell which group they had been assigned to, and the group with the warmer vest could be used as a comparison.

The authors found that "in contrast to sham cooling, active cooling resulted in a significant improvement of fatigue, muscle strength in the lower limbs, and standing balance with eyes closed."

When they measured the concentration of nitric oxide (NO) in the white blood cells of the patients and healthy volunteers, they found that people with MS have higher concentrations of NO than people without the disease. And they also found that active cooling decreased the amount by about 41%, whereas sham cooling did not affect the concentration of NO.

"Contrary to popular belief, the beneficial effects of the cooling garment can't be explained simply by direct cooling of the central nervous system," De Keyser says. "These results raise the intriguing possibility that lowering of nitric oxide productions may play an important role in this."

"Other studies have shown some benefit from cooling, especially if you don't use the mechanical kind of vest [the type used in the current study]," says Nicholas LaRocca, PhD, director of healthcare delivery and policy research at the National Multiple Sclerosis Society in New York City, who discussed the study with WebMD.

"What's new is this concept of the possible role of nitric oxide in this process," LaRocca says. "But it's unclear from the study if that's really the explanation for the findings or if there might be another explanation. Part of the problem is that when you cool the body, you are affecting almost every metabolic process. So yes, nitric oxide levels might be affected, but if you evaluated all sorts of physiological factors, you would find that they are also affected."

Medically Reviewed
By Dr. Gary Vogin
© 2001 WebMD Corporation. All rights reserved.

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