The Way Your Brain 'Cleans House' Could Point to Alzheimer's Disease

A key protein involved in Alzheimer's disease is produced at a normal rate but is not sufficiently removed in the disease.

 Researchers have found that while beta-amyloid production was similar in Alzheimer's and healthy people, the clearing away of the amyloid plaques was significantly less in Alzheimer's patients. The discovery may point the way to improved testing measures for early diagnosis and better treatment.

Alzheimer's disease is characterized by dense protein clumps (amyloid plaques) that develop between brain cells. These plaques are made mostly of beta-amyloid, produced by nerve cells and released into surrounding brain fluid. Thanks to recent research, beta-amyloid levels in cerebrospinal fluid (CSF) are useful in diagnosing Alzheimer's.

For this study, Dr. Randall Bateman at Washington University in St. Louis and a team of cohorts measured beta-amyloid production and clearance rates in 12 late-onset Alzheimer's and in 12 control-group patients of the same age. The researchers were able to calculate how fast beta-amyloid was produced -- and cleared -- in participants' brains using a non-radioactive isotope. The clearance of beta-amyloid was roughly 30 percent slower in Alzheimer's patients, researchers found.

About 5 million Americans have Alzheimer's disease, the leading type of dementia in the United States.