Brain drain might help Alzheimer's patients
Dec. 27, 2002

By DAN VERGANO
Gannett News Service

A brain fluid “oil change” may help Alzheimer’s patients, neurosurgeons report.

In the latest issue of Neurology, researchers describe early success using a shunt device, which when implanted in the brain constantly drains off small amounts of the fluid the brain produces. Researchers theorize that the poor turnover of this fluid may contribute to the buildup of plaques and tangled nerve fibers that are the hallmark of Alzheimer’s.

Afflicting about 4 million people nationwide, Alzheimer’s is the most common cause of dementia in the elderly. Health experts view the disease with increasing concern, given the overall aging of the U.S. population and a lack of effective treatments.

In a year-long experiment led by Gerald Silverberg of California’s Stanford University School of Medicine, researchers tested the drain in the hope that it would increase brain fluid production and in turn remove harmful proteins.

Limited turnover of fluid, continually produced and reabsorbed by the brain, has long been linked to dementia. “In a healthy person, the fluid may turn over three to four times a day,” Silverberg says. “In an Alzheimer’s patient, it may drop to once a day.”

Experiments in the 1960s that removed fluid in dementia patients produced mixed benefits, but they also triggered bleeding in the brain because of sudden drops in fluid pressure.

To avoid those problems, Silverberg’s team implanted a “low-flow” drain, or shunt, in 12 Alzheimer’s patients. Similar in size to the tip of a pinkie finger, the shunt maintains a constant low flow of spinal fluid and avoids overdraining to prevent bleeding. It removes about 3 ounces of fluid daily from the brain, which regularly produces perhaps 15 ounces.

In follow-up tests, researchers found that drain patients’ scores on dementia tests had stabilized, while patients without a shunt received worsening scores. Furthermore, Alzheimer’s related proteins in the shunt-equipped patient’s brains decreased over time.

None of the shunt patients suffered bleeding in the brain.

One patient suffered an infection that was treated with antibiotics. Other patients experienced and recovered from seizures, which is not uncommon in Alzheimer’s patients.

Despite the results, “the likelihood we’re going to shunt 4 million people with Alzheimer’s is very small,” says Bill Thies of the Alzheimer’s Association. He cautions against too many expectations over the shunt study, noting that it was designed primarily to test for safety, not disease-fighting benefits. “We don’t know whether it works really. This is very preliminary data.”

The researchers plan additional tests during an 18-month study involving hundreds of patients.

Silverberg suspects the increased turnover in brain fluid triggered by the drains may help clear proteins from the brain. Or draining fluid may improve the pumping action of blood vessels and move proteins away from the recesses of the brain.

Eunoe Inc., a company started by Silverberg and his colleagues, funded the research. The firm makes the shunts used in the study. A Stanford Alzheimer’s research fund also contributed to the research.

“It still is very experimental,” Silverberg says.