A common tuberculosis drug may help patients with Parkinson's disease — and, perhaps, Alzheimer's and Huntington's diseases as well.

The drug is rifampicin (search). Although better known as a tuberculosis drug, rifampicin is also an effective treatment for leprosy (search). More than a decade ago, researchers discovered that leprosy patients on long-term rifampicin therapy had less dementia and senile plaques (search) in their brains than untreated patients.

That finding led to intense research on how the drug might affect brain diseases. Now researchers led by Anthony Fink, PhD, at the University of California, Santa Cruz, have at least part of the answer.

During Parkinson's disease (search), a common brain protein called alpha-synuclein gathers into fiber-like particles — fibrils — that clog the brain. Fink's team shows that rifampicin stops these fibrils from forming. More importantly, the researchers find that the drug causes already-formed fibrils to unravel.

The implication: Rifampicin may work as a treatment for Parkinson's disease.

"Clearly, more work is needed to determine if this would work therapeutically," Fink says, in a news release. "But if it does, it would probably be most useful as a [preventive] therapy used in the early stages of the disease before there is general neurological damage."

Fink and colleagues report their findings in the November issue of Chemistry & Biology. In an accompanying editorial, Aphrodite Kapurniotu of the Institute of Biochemistry, RWTH Aachen, Germany, notes that the findings may lead to new treatments for Parkinson's disease.

The gathering — biochemists prefer the term "aggregation" — of normal proteins into disease-causing fibers isn't unique to Parkinson's disease, Kapurniotu notes. Other diseases come from similar processes: Alzheimer's disease, Huntington's disease, mad cow disease, and even type 2 diabetes.

"Recent evidence suggests that common molecular events may underlie the pathogenesis of [these] different 'protein aggregation' diseases," she writes.

By Daniel J. DeNoon, reviewed by Brunilda Nazario, MD

SOURCES: Li, J. Chemistry & Biology, November 2004; vol 11: pp 1513-1521. Kapurniotu, A. Chemistry & Biology, November 2004; vol 11: pp 1476-1478. News release, University of California, Santa Cruz.