Researchers at Columbia and Stanford universities believe that Alzheimer's disease may result from the malfunctioning of brain cells called astrocytes, raising hopes that activating these astrocytes may benefit sufferers of the disease.

Most experts believe that Alzheimer's disease is caused when small peptides called beta-amyloid accumulate in the brain. Such peptides are made at all times during a person's life, but Alzheimer's sufferers seem to have too many of them. The excessive peptides aggregate together to form plaques that cause neurons to die.

The new research, reported in the April issue of Nature Medicine, suggests that beta-amyloid accumulates in people with Alzheimer's disease because the astrocytes fail to destroy it.

"This is the first study to show that astrocytes can remove beta-amyloid deposits from brain tissue," said study author Dr. Jens Husemann, associate research scientist at Columbia University College of Physicians and Surgeons. "Now researchers will explore ways to activate astrocytes to increase beta-amyloid removal."

In their study, the researchers found that astrocytes ingest beta-amyloid when they placed cultured adult mouse astrocytes onto brain tissue taken from mice with Alzheimer's disease. The cells reduced the amount of beta amyloid in the brain tissue by 40 percent during the 24-hour experiment.

Though improving the ability of astrocytes to destroy beta-amyloid may be therapeutic, the researchers caution that other astrocyte functions such as inflammation may actually contribute to Alzheimer's disease.

"It will be a delicate balancing act to stimulate plaque removal while keeping inflammation down at the same time," said Husemann.

Other sources: Columbia University College of Physicians and Surgeons