Gout and multiple sclerosis (MS) may seem worlds apart, but researchers may have found a positive link between the two disorders. A new study indicates that uric acid - a compound that forms in the tissues in people with gout - prevents paralysis and death in mice with lesions resembling those seen in MS humans. The results, reported in the current issue of Proceedings of the National Academy of Sciences , suggest that this unlikely candidate drug could one day be used to treat a condition that in the United States now affects some 300,000 people, most of whom are between 35 and 65.
people with MS - a mysterious degenerative disease characterized by muscle weakness and, in advanced cases, paralysis and mental disorders - have damage to nerve cells in the brain and spinal cord containing high levels of neurotransmitter nitric oxide (NO). Thinking that high concentrations of corrosive NO may play a role in nerve damage, Hilary Koprowski and colleagues at Thomas Jefferson University in Philadelphia tested three compounds in mice - uric acid, PTIO and D609 - which are known to trap or inhibit NO production.
They first injected a fragment of myelin protein in the brains of test mice, which causes nerve damage similar to that seen in patients with multiple sclerosis. Normally, the fixed paralysis within 2 weeks, the mice died within 3 weeks. The group Koprowski found that daily injections of 20 milligrams of uric acid prevented the paralysis in mice; other drugs conjured paralysis for a few days. Some scientists believe that the low uric acid levels may even play a role in the disease. "The idea that the reduction of certain natural chemicals in the body may cause MS is a new concept," says Mohamed Rostami neurologist at the University of Pennsylvania.
Because uric acid is not a foreign compound body- -that a metabolite of caffeine and other purines - Koprowski think it an ideal drug candidate. "You're not bringing in a new strange substance or drug," he said. "You have to increase the natural levels in the body." Other experts are more skeptical. "There are many things who worked in [the mouse model] who have not worked in MS, or have only modest effects, "says neurologist Robert Lisak of Wayne State University in Detroit. Koprowski said his group plans to determine whether people with MS have lower levels of uric acid than the healthy people and if the gout patients have a lower incidence MS.
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