Immune System Problem Linked to Alzheimer's

Defective Cells May Be Unable to Clean Up Brain Plaque in Alzheimer's Disease

From the WebMD Archives

June 10, 2005 -- New research shows that plaque buildup in the brains of Alzheimer's patients may be related to immune system problems.

Researchers in California recently studied 24 people with probable or possible Alzheimer's disease, as well as 20 healthy people. The results appear in the Journal of Alzheimer's Disease.

Alzheimer's disease Alzheimer's disease gradually damages areas of the brain involved in memory, intelligence, judgment, language, and behavior. A main cause is thought to be the buildup of plaque in the brain. It's the most common form of dementia, or mental decline, in older adults.

Alzheimer's disease is most common among older adults, but it's not a normal part of aging. The Alzheimer's Association says 4.5 million Americans have Alzheimer's disease. That's twice as many as in 1980, but far less than the 11-16 million cases that the group says could be seen by 2050 due to the aging population.

Immune System Problem

In the new study, scientists tested participants' blood. The researchers spotted a difference in immune system cells called macrophages.

"Macrophages are the janitors of the innate immune system, gobbling up waste products in the brain and throughout the body," says researcher Milan Fiala, MD, in a news release. Fiala works in the medical school of the University of California Los Angeles (UCLA), as well as the Greater Los Angeles VA Medical Center.

Participants' macrophages took a test-tube challenge: Clear away amyloid-beta, a building block of Alzheimer's-related brain plaque. Macrophages from healthy participants were up to the task, but those from Alzheimer's patients couldn't clean up adequately. Other parts of the immune system may have to step in to get the job done, say the researchers.

Searching for Solutions

"If further study shows that this defective macrophage function is present in most Alzheimer's disease patients, new hormonal or immune-boosting approaches may offer new approaches to treating the disease," says Fiala.

He says the immune system glitch may also be present in other diseases involving a buildup of waste and plaques, such as heart disease and Gaucher disease, a rare metabolic condition.

Fiala and colleagues are currently doing lab tests with a naturally occurring hormone called insulin-like growth factor. They also plan to investigate other natural substances, such as curcumin, a chemical in the curry spice turmeric, says the news release. Curcumin has shown potential against Alzheimer's diseaseCurcumin has shown potential against Alzheimer's disease and cancer in other experiments on mice.

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SOURCES: Fiala, M. Journal of Alzheimer's Disease, June 10, 2005. WebMD Medical Reference from Healthwise: "Alzheimer's Disease -- Topic Overview." Alzheimer's Association, "About Alzheimer's -- Statistics About Alzheimer's Disease." News release, UCLA. WebMD Medical News: "Curry Spice May Fight Alzheimer's Disease." WebMD Medical News: "Curry Spice May Curb Breast Cancer's Spread."

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