The study, reported in the November 7 issue of Nature, was conducted in mice with experimental autoimmune encephalomyelitis (EAE), the standard animal model for multiple sclerosis. Multiple sclerosis causes a variety of symptoms, mostly related to motor control. A primary symptom is temporary, recurring paralysis in the limbs, as occurs in the mice.
The researchers examined the effects of atorvastatin in two models of mouse EAE that may reflect conditions that occur in multiple sclerosis. When atorvastatin was given at the onset of symptoms in a model where mice develop chronic paralysis, which can occur in some forms of later-stage multiple sclerosis, the drug lessened the paralysis. In this same model, when the drug was given during the acute attack, it suppressed paralysis.
When the drug was given to mice with relapsing-remitting disease, the most common form of multiple sclerosis, the results were more dramatic. In mice experiencing their first attack, the drug prevented the animals from progressing to the fully established disease. In animals that had already had an initial attack and were developing the symptoms of a first relapse (second attack), the drug reversed the emerging paralysis.
"The findings are provocative," said the senior author of the study, Scott S. Zamvil, MD, PhD, assistant professor of neurology at University of California, San Francisco. At the same time, he cautioned, "we need to do clinical trials in patients to determine if we see the same positive results."