Lipitor is one of the statin drugs used to lower cholesterol. Statins have additional properties, such as regulating nitric oxide syntheses and inflammatory response, that may treat HD. (ref)
It is curious that many HD patients develop AD lesions early in the course of HD but the AD pathology progresses slowly. (ref) It is as if patients with AD and HD are protected from the progression of AD by having HD. --Jerry, 09-Sep-01
LOS ANGELES (Reuters) 06-Sep-01
| A popular cholesterol-lowering drug, Lipitor, is being studied as a treatment for Alzheimer's Disease, researchers said on Thursday. |
``We have found that individuals with high cholesterol levels have an increased risk of developing Alzheimer's,'' Dr. Larry Sparks, senior scientist at the Sun Health Research Institute in Sun City, Arizona, and the study's lead researcher, told Reuters.
``We believe cholesterol from the blood, over a long period of time, also gets in the brain where it promotes the production of a toxin that causes the disorder,'' he added.
The scientist said he thinks that people who are healthy enough not to succumb to heart disease, but have elevated cholesterol, still face the risk of future dementia.
Alzheimer's, the most common form of dementia, affects an estimated 4 million Americans, with the number expected to rise sharply in line with an aging population. The degenerative brain disease is caused by buildup in the brain of sticky plaques made up of deposits of a protein called amyloid beta, which is toxic to cells.
``There is a lot of data from studies in test tubes and animals showing that cholesterol plays an important role in the deposition of amyloid in the brain,'' explained Dr. Howard Fillit, executive director of the Institute for the Study of Aging in New York, which is partly funding the study.
Retrospective studies have also shown that people who take cholesterol-lowering drugs for heart disease are at lower risk of developing Alzheimer's, he said.
Statins, on the market since 1987, are a class of drugs that lower blood levels of low-density lipoprotein -- LDLs, the so-called bad cholesterol -- by 25 percent to 50 percent. The drugs, which limit cholesterol production in the liver, are commonly prescribed for people who are at risk of heart disease.
Sparks said he chose Lipitor, made by Pfizer Inc. over the other drugs in the class, which include Merck & Co.'s Zocor and Bristol-Myers Squibb Co's. Pravachol, because it offered the best safety profile.
Another drug in the class, Bayer AG's Baycol, was pulled from the market last month after being linked to 52 deaths from severe muscle weakness.
``This is an investigator-initiated study. I chose Lipitor because it doesn't cross the blood-brain barrier,'' Sparks said, noting that Pfizer decided to partly fund the study after being contacted.
He explained that a cholesterol-lowering drug that directly penetrates the brain could present a danger to patients since it could inhibit cholesterol synthesis within the brain.
``The idea is to make the blood act like a sponge that passively draws out the cholesterol,'' Sparks said.
As yet, there are no drugs to treat the underlying causes of Alzheimer's. A relatively new class of drugs known as cholinterase inhibitors are used to reverse mild cognitive problems in patients in the early stages of the disease.
``If cholesterol induces production of the toxin that cause AD (Alzheimer's Disease), we would actually have a disease-modifying effect, rather than just treating symptoms,'' Sparks said.
Enrollment in the single-site trial of 120 patients with mild to moderate Alzheimer's has begun and results are expected in about two years, the scientist said.