030425 - Cholesterol Drugs May Improve Alzheimer Risk Marker

By Linda Carroll 

NEW YORK (Reuters Health) - Cholesterol-lowering drugs called statins may lower levels of a substance that appears to raise the risk of Alzheimer's disease (news - web sites), a new study shows. 

Blood levels of a substance called 24S-hydroxycholesterol were reduced by over 20 percent after six weeks of treatment with a statin, researchers report in the journal Archives of Neurology. 

Studies have shown that Alzheimer's patients tend to have high levels of 24S-hydroxycholesterol, which is produced almost exclusively by the brain. And scientists suspect that high levels of the compound reflect high cholesterol levels in the organ. 

One line of evidence comes from animal studies, study co-author Dr. Myron F. Weiner, a professor of psychiatry at the University of Texas Southwestern Medical Center in Dallas, explained in an interview with Reuters Health. 

"When you lower the level of cholesterol in mice that are a model for Alzheimer's disease, then you get fewer plaques in the brain," Weiner said. Amyloid plaques are one of the hallmarks of Alzheimer's disease in humans. These waxy build-ups appear to damage brain cells. 

In the new study, Weiner and his colleagues treated 44 Alzheimer's patients with one of three statins -- lovastatin, simvastatin or pravastatin sodium -- or extended-release niacin, which is a non-statin cholesterol-lowering drug. 

At the beginning of the study patients had total cholesterol levels of at least 200 milligrams per deciliter of blood (mg/dL). 

At the end of six weeks, all four groups experienced a lowering of both LDL cholesterol -- the "bad" form of cholesterol -- and 24-S-hydroxycholesterol. 

Statins produced the largest declines in both substances. Levels of 24-S-hydroxycholesterol dropped by about 21% in people taking statins and about 10% in people taking niacin. Statins lowered LDL levels by about 35%, while niacin reduced "bad" cholesterol by 18%. 

"Our assumption is that this means that their brains are producing less cholesterol," Weiner said. 
The study doesn't prove that statins help stave off or slow Alzheimer's, Weiner said. But there is an ongoing clinical trial designed to test that very hypothesis, he added. 

"We've demonstrated that you can give statins to patients with normal blood cholesterol and not cause any harm, while reducing the brain's production of cholesterol," Weiner said. 

SOURCE: Archives of Neurology 2003;60:510-515. 
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