Blood Marker Could Point to Alzheimer's Risk

Taking advantage of the ongoing Framingham Heart Study, Tan and his colleagues periodically tested the blood of 691 healthy elderly participants averaging 79 years of age. Then they tracked the volunteers' mental health for the next seven years.

Over that period of time, 44 of the participants developed Alzheimer's disease.

The researchers found that individuals with the highest levels of mononuclear cell-derived inflammatory cytokines were twice as likely to develop the illness as those with the lowest levels of the inflammatory markers.

"So, our hypothesis now is that it is possible to indirectly measure [Alzheimer's-linked] brain inflammation by looking at the amount of inflammatory markers released by these blood cells, cells that may eventually make it to the brain," Tan said.

One expert agreed the finding could someday lead to a real advance in the care and understanding of Alzheimer's disease.

"What this study does is take us to another level in terms of diagnostics," said Paul Sanberg, director of the Center of Excellence for Aging and Brain Repair at the University of South Florida College of Medicine, in Tampa. "They are finding a more consistent result when they look at the inflammatory markers in mononuclear cells."

He said the jury is still out on whether treating inflammation might prevent or treat Alzheimer's, since no one is sure whether inflammation helps cause the disease or is simply a product of the illness.

But if it turns out that dampening inflammation can help, a blood test measuring these cytokines might be of great use to doctors, Sanberg said. "If you can find a consistent marker, then maybe some patients might be treated by anti-inflammatories better than others, depending on the [blood] level of these markers," he said.

Tan agreed that it's too early to talk about treatments, but he believes the new finding brings effective diagnostics and therapy that much closer.

"This is another piece of the puzzle in the mechanism of Alzheimer's disease," he said.

More information

There's more on Alzheimer's disease at the Alzheimer's Association.

SOURCES: Zaldy Tan, M.D., director, Memory Disorders Clinic, Beth Israel Deaconess Medical Center, Boston; Paul Sanberg, Ph.D., distinguished professor, and director, Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa; May 29, 2007,Neuroloy