California scientists say a statin drug already used by millions of heart patients to lower harmful cholesterol levels has improved and even reversed some of the debilitating symptoms of multiple sclerosis in mice.

And while that does not prove the drug would work for humans, another study using a second statin drug on a small number of MS patients is showing early positive signs.

“The animal data is quite striking,” said the senior author of the mouse study, neurologist Scott Zamvil of the University of California-San Francisco. “We didn’t have any conflicting data.”

Other researchers said the California results, if they can be repeated in humans, could help launch statins into the exceptional class of drugs like aspirin that were developed to treat one type of illness but turn out to offer a range of medical benefits.

They said the drugs’ anti-inflammatory effects might also be effective in treating rheumatoid arthritis, juvenile diabetes and other autoimmune diseases in which the body mistakenly turns its biochemical guns on healthy tissue. Other trials suggest statins might protect against Alzheimer’s, too.

But scientists urged physicians and their patients not to rush to use statins to treat MS until the mice study finding is safely evaluated in humans, which could take several years.

Currently, the small clinical trial is evaluating simvastatin sold as Zocor on 32 MS patients in three states. Those results could be published next spring, researchers said.

“There is accumulating data that would strongly suggest that statins should have a positive effect,” said neurologist William Tyor of the Medical University of South Carolina in Charleston who is coordinating part of the human trial.

MS is a degenerative disease of the central nervous system. High levels of one of the body’s immune chemicals gamma interferon wrongly activate T-helper cells to mount an inflammatory attack on the myelin sheath that insulates nerve fibers.

Accumulating scar tissue slows the transmission of nerve impulses and interrupts cell communication, leading to episodes of paralysis, tremors and blurry vision.

The California study published in the current issue of the journal Nature was limited to high doses of atorvastatin, sold under the brand-name Lipitor.

At UCSF and Stanford University, mice were bred to develop experimental autoimmune encephalomyelitis, or EAE, which mimics MS in lab animals.

The mice were given doses of atorvastatin equal to 80 milligrams, the highest dosage approved for humans. Heart patients typically receive lower doses to reduce cholesterol.

Among mice experiencing their first MS-like attack, Zamvil said high doses prevented the animals from developing permanent symptoms.

Among animals that were suffering a relapse, the drug reversed emerging paralysis and restored mobility.