Immune System Problem Linked to Alzheimer's
Defective Cells May Be Unable to Clean Up Brain Plaque in Alzheimer's Disease
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.
dementia, or mental decline, in older adults.
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
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
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
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. and cancer
in other experiments on mice.