Fooling Alzheimers Disease With a Decoy Drug

March 17, 2005 -- Scientists are working on a new drug that outsmarts Alzheimer's disease, the most common form of mental decline in older adults.

The drug is in its fledgling stages. So far, it's only been tested on cell samples. It's not a cure; instead, it tricks toxic brain proteins linked to Alzheimer's disease, sidelining them before they form plaques and tangles that burden patients' brains.

"This work may lead to the development of new tools and/or therapeutics for use in Alzheimer's disease," says researcher Theresa Good, PhD, a chemist with the University of Maryland-Baltimore County.

Good says the drug has fared well in lab tests on cells, but it hasn't yet been tried in animals or people.

"Of course, there is a long way to go before one can use these molecules in the human body," she says. But so far, lab tests on cells look promising, she notes.

If successful in people, such decoy drugs might be used in injections or pills, says Good, in a news release. The drugs could be used for people who don't have Alzheimer's disease but are at high risk for it; they would probably have to take the drugs for the rest of their lives to hold off the disease, she continues.

An estimated 4.5 million people in the U.S. have Alzheimer's disease. That includes one in 10 people over age 65 and nearly half of those older than 85, says the Alzheimer's Association.

By the year 2050, as many as 11.3 to 16 million people in the U.S. could have Alzheimer's disease, says the Alzheimer's Association.

Alzheimer's disease progressively damages areas of the brain involved in memory, intelligence, judgment, behavior, and language. Memory loss is often the first sign people notice, but short-term forgetfulness in older people doesn't always point to Alzheimer's disease.

For instance, normal forgetfulness might be forgetting where your car is parked. Forgetfulness that may be caused by Alzheimer's could be forgetting how to drive a car at all. Check with your doctor for any concerns about memory lapses.

Today, doctors use patients' symptoms, medical history, physical exam, and mental tests to check for Alzheimer's disease. But the definitive diagnosis only comes when the brain is examined after death.

Autopsies have shown senile plaques and tangles in the brains of deceased Alzheimer's patients. Those tell-tale signs are made of beta-amyloid protein, which the new drug targets.

Baiting Toxic Brain Proteins

The experimental drug doesn't try to blast and bombard beta-amyloid. Instead, it takes a sneakier approach.

The drug is built to attract beta-amyloid proteins and hold on tight. That way, the proteins don't have the chance to form senile plaque. The drug could also serve as a marker for the harmful beta-amyloid proteins, perhaps leading to an Alzheimer's test for living patients.

The drug is also designed to resemble parts of healthy human brain cells. Hopefully, that will help avoid side effects, says Good, in a news release. She notes that many other promising drugs flunked over dangerous side effects. For instance, an experimental vaccine against beta-amyloid was dropped after it caused severe immune responses in animal tests.

Those hurdles lie ahead for the decoy drug, which is being developed by Good, and colleagues from Texas A&M University. "Eventually, we think we'll be able to make better decoys using molecular design," she says, in the news release.

The findings were presented in San Diego, at a national meeting of the American Chemical Society.