INFECTION CONTROL: Bacterium Could Be Alzheimer’s Risk*

by R.A. Clappison, DDS, FRCD(C)

Brian J. Balin and his team at the Allegheny University of the Health Sciences in Philadelphia, PA, reported that his team discovered segments of the DNA of the bacterium, Chlamydia pneumoniae , in the brain samples of 17 of 19 dead Alzheimer patients. On the other hand, 18 of 19 people without Alzheimer’s disease showed no sign of the bacteria.

Brain cells infected by the organism create inflammatory chemicals called cytokines to deal with the infection. These cytokines can damage adjacent nerve cells.

Chlamydia pneumoniae has also been observed in the fatty plaques that clog heart arteries although it is not known if it is responsible for the clogging. Late-onset Alzheimer’s was also associated with infection with herpes simplex type 1.

Zaven Khachaturian, a consultant to the Alzheimer’s Association and former Director of the Office of Alzheimer’s Disease Research at the National Institutes of Health in Washington, said that it would be important to discover whether the bacteria set the stage for the disease or whether the brain, damaged by the Alzheimer’s disease, allowed the bacteria to enter.

Chlamydia pneumoniae is commonly found in the sinuses and lungs and its discovery in the brain was not expected since the organism must penetrate the protective blood-brain barrier. Khachaturian found the findings “exciting” because the issue of what is causing the degenerative process needs to be answered.

* Jane E. Allen, Associated Press, Naples Daily News, Nov. 12, 1998