By Peggy Peck – The cholesterol-lowering drug Lipitor may also be good for the brain, according to new research that suggests high doses of the drug can slow the progression of Alzheimer's disease.
The link, says Alzheimer's disease researcher D. Larry Sparks, PhD, is cholesterol, which serves as fuel for formation of plaque, the waxy clumps and tangles of protein that are found in the brains of Alzheimer's disease patients. This plaque, according to Alzheimer's disease researchers, interferes with brain functioning, destroying memory and thinking ability.
Lower Cholesterol Stabilizes Alzheimer’s Disease
Sparks, who presented his study results at the American Heart Association's Scientific Sessions 2004, tells WebMD that when "you lower the cholesterol; you lower the level of beta-amyloid." Beta-amyloid (search) is the sticky substance that forms the plaque.
In the study, 25 people with early signs of Alzheimer's disease took 80 mg of Lipitor for a year, while 17 with Alzheimer's disease took a placebo. Those who took Lipitor "had a clear clinical benefit,” Sparks says. He found that their memory and thinking abilities did not decline.
“At minimum, the drug delays entrance to nursing homes; at best, it improves the quality of a patient's life," he says.
On memory and thinking tests, Alzheimer’s disease patients taking Lipitor showed no change over the 12-month study, while many patients taking a placebo showed evidence that the disease had progressed.
Overall, 53 percent of the Alzheimer’s disease patients taking Lipitor stabilized or improved, compared with 28 percent of patients taking a placebo. Sparks conducted the study at the Sun Health Research Institute in Sun City, Ariz., where he is senior scientist and chief of the Roberts Laboratory for Neurodegenerative Disease Research.
He says initially, Alzheimer’s disease patients taking Lipitor were no different than patients taking a placebo, but "after three months, they took off. That is when the difference was really apparent." Lipitor does not enter the brain, so the observed improvements must be related to decreases in cholesterol levels in the blood, says Sparks.
How Lipitor Helps Alzheimer’s Disease
Sparks theorizes that when the cholesterol levels in the blood go down in response to treatment, levels of beta-amyloid also decline. This leads to excess beta-amyloid moving from the brain to the blood, he suggests.
Another possibility is that Lipitor breaks down the beta-amyloid into a form that is more easily cleared from the body.That, however, is theory since the only way to really measure amyloid is to autopsy the brain, William Thies, PhD, vice president of medical and scientific affairs for the Alzheimer's Association, tells WebMD. "All he is reporting in this study is clinical results; there is no autopsy evidence that amyloid in the brain is reduced," says Thies, who wasn't involved in the study.
Thies says, however, that the results of the new study are promising.Samuel Gandy, MD, PhD, professor of neurology and director of the Farber Institute at Thomas Jefferson University in Philadelphia, tells WebMD Sparks’ study is encouraging but preliminary. He says Sparks was the first researcher to begin pursuing the cholesterol-Alzheimer's link."And this is definitely the first clinical trial to report a benefit," says Gandy.
He says two other studies of similar cholesterol-lowering drugs are under way, including a National Institutes of Health study of the drug Zocor, which not only treats cholesterol in the blood but also enters the brain.Though Sparks is enthusiastic about his results, he says it is too early to recommend giving Lipitor or other cholesterol-lowering drugs to prevent or treat Alzheimer's disease.
SOURCES: American Heart Association Scientific Sessions 2004, New Orleans, Nov. 7-10, 2004 D. Larry Sparks, PhD, senior scientist, Roberts Laboratory for Neurodegenerative Disease Research, Sun City, Ariz. Samuel Gandy, MD, PhD, professor of neurology and director, Farber Institute, Thomas Jefferson University, Philadelphia. William Thies, PhD, vice president of medical and scientific affairs, Alzheimer's Association.