U.S. researchers have discovered that some painkillers may be protective against Alzheimer's disease. The drugs appear to prevent the formation of brain plaques, a hallmark of Alzheimer's disease.
Scientists first learned of the potential benefits of so-called non-steroidal anti-inflammatory drugs, or NSAIDS, by accident. Todd Golde of the Mayo Clinic in Jacksonville, Florida says the connection emerged in studies of elderly individuals conducted years earlier. He said, "They looked at people taking high doses of non-steroidals, for example, rheumatoid arthritics. And they showed, in this population, they had a big decrease in the incidence of Alzheimer's disease you know, 50 percent, 60 percent."
Experts believe that brain deposits of a protein known as amyloid beta cause Alzheimer's disease.
Researcher Todd Golde and colleagues at the University of California wanted to find out whether non-steroidal anti-inflammatory drugs reduce the formation of harmful amyloid-beta brain plaques. Using mice and human cell cultures, the investigators describe their work in the journal Proceedings of the National Academy of Sciences.
Dr. Golde says their discovery surprised researchers because they had always assumed the protein deposits were the product of inflammation, or infection and swelling, somewhere in the body. And non-steroidal anti-inflammatory drugs work by eliminating one mechanism of inflammation.
He says the latest study suggests the anti-inflammatory action of the drugs is not what is working to prevent Alzheimer's. "People have done trials with steroids," he said, "which are potent anti-inflammatory molecules, and they have not been effective in reducing the prevalence of Alzheimer's disease or slowing down the progression of Alzheimer's disease."
Instead, scientists believe Alzheimer's is being prevented by a side effect of some non-steroidal anti-inflammatory drugs.
Leon Thal is chairman of the Department of Neurology at the University of California in San Diego, where the study's other investigators are located. "Many neuroscientists," he said, "now believe that the cause of Alzheimer's disease is either an overproduction or a misprocessing of amyloid. So, there is an intense search underway for drugs that can reduce the production of amyloid. So, if it turns out that certain classes of non-steroidal anti-inflammatory drugs reduce the production of amyloid, this is a good thing. But in all probability, the doses that are needed are such that current non-steroidal anti-inflammatory drugs would probably not be useful. Because the doses needed to give people are way too high."
Work is continuing to figure out why some non-steroidal anti-inflammatory drugs are effective in reducing Alzheimer's brain plaques and others are not. Since the harmful amyloid deposits begin to form many years before the appearance of symptoms, like dementia, investigators are also trying to learn how soon these drugs would have to be given to patients to be effective.