Common Bacteria Linked to Alzheimer's Disease

Newswise — The paper "Chlamydia pneumoniae induces Alzheimer-like Amyloid Plaques in Brains of BALB/c Mice," to be published in the April issue of Neurolobiology of Aging shows a link between the bacteria Chlyamydia pneumoniae and the amyloid plaques found in the brains of people who have sporadic, non-hereditary Alzheimer's Disease.

Researchers at Philadelphia College of Osteopathic Medicine's Center for the Study of Chronic Diseases of Aging have been studying a link between this common respiratory bacteria and pathology consistent with Alzheimer's Disease for several years. This most recent work builds on their ground-breaking research published in Medical Microbiology and Immunology in 1998 that discovered Chlamydia pneumoniae in 90 percent of brains taken from individuals who had suffered from Alzheimer's Disease. Their new work shows that the bacteria, when sprayed into the noses of mice not predisposed to amyloid plaques, can cause progressive deposition of amyloid plaques, in essence creating a partial model of Alzheimer's Disease.

"We believe this could be a trigger mechanism for the pathology in Alzheimer's Disease," says lead researcher Brian Balin, Ph.D. "People have been suspecting this for decades but could not find anything. It is very difficult to pinpoint an infectious cause for a progressive, chronic disease. We also believe that our isolation of Chlamydia pneumoniae from the human Alzheimer's Diseased brain and induction of pathology in normal mice is proof of principle that this can be a causative mechanism turning on pathology."

At one time, Alzheimer's was thought to be a hereditary disease. Research has shown that only two-to-five percent of Alzheimer's cases have a genetic tie. Fifty percent of people who reach age 85 will develop Alzheimer's

Balin is already looking further ahead. He wants to set up clinical trials in patients with late-onset AD to investigate the effect of typical antibiotics used for treating C. pneumoniae infections. But there is a lot of controversy now whether any existing antibiotics for C. pneumoniae can truly clear the organism from our bodies. "We try to intervene by using an antibiotic approach initially," says Balin. "I think it would offer hope to a patient that would have sporadic AD and would be diagnosed with having chlamydia infection as well. But in reality we are not sure whether the antibiotic approach will be sufficient to actually eradicate. Right now, we are thinking that combining antibiotics and anti-inflammatory drugs might be instrumental in treating AD, but obviously we do not have a final answer on that."

To access Neurobiology of Aging: http://www.sciencedirect.com/science/journal/01974580