Scientists slow progress of Huntington's in mice

May 20, 1999
Web posted at: 11:44 AM EDT (1544 GMT)

(AP) -- Scientists have found a way to delay the onset of Huntington's disease and slow its progress in mice by targeting an enzyme that is believed to trigger cell death.

The finding, published in Thursday's issue of the journal Nature, is a promising lead for drug researchers working to extend the lives of Huntington's sufferers.

"I think this is important and exciting. This is the first demonstration of a drug that can slow the progress of HD in an animal model," said Dr. Christopher Ross, a Johns Hopkins Medical School professor and a scientific adviser to the Huntington's Disease Society of America. "It says this goal of slowing progress probably can be accomplished."

Huntington's has been linked to enzymes called caspases, which cause brain cells to die slowly.

In the new study, scientists from Harvard University's Brigham and Women's Hospital blocked a particular caspase in mice that had been genetically engineered to contract the disease. These mice developed Huntington's symptoms about 10 percent later in life and lived about 20 percent longer.

Caspase-1 apparently plays a role in the cell death that marks Huntington's, which usually kills sufferers within 15 to 20 years. How the enzyme works is unclear, but scientists think that it slices up the so-called huntingtin gene, and that the fragments then kill the cell.

The Harvard researchers slowed that process by breeding mice with a mutant protein that counteracts caspase-1.

The mice showed Huntington's symptoms -- walking trouble, weight loss and seizures -- after 84 days, on average, compared with 77 days in the other mice. The mice with the caspase blocker lived an average of 121 days, compared with 101 days for the other mice.

"If one drug can do this, hopefully, in the future, you can find others," said one of the researchers, Dr. Robert M. Friedlander.

Huntington's, which killed folk singer Woody Guthrie, afflicts 30,000 Americans.

What is exciting, Friedlander said, is that the same mechanism at work in this study may be applied to research on brain injuries and illnesses such as Lou Gehrig's disease and Parkinson's.

"Caspase inhibition may turn out to be the magic bullet against neurodegenerative disease," University of Munich biochemist Christian Haass said in an accompanying editorial.

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