Alzheimer's Disease Linked to Common Bacterium

Researchers have found a link between Chlamydia pneumoniae, a common airborne bacterium, and Alzheimer's disease (AD). Their findings were published in the April 2004 issue of Neurobiology of Aging.

The researchers demonstrated that bacteria sprayed into the noses of mice not predisposed to amyloid plaques could cause progressive deposition of plaques, creating a partial model of AD. This finding builds on previous research that found Chlamydia pneumoniae in 90% of brains taken from patients with Alzheimer's disease.

"We believe this could be a trigger mechanism for the pathology in Alzheimer's disease,” said lead researchers Denah Appelt, Ph.D., and Brian Balin, Ph.D., of the Center for the Study of Chronic Diseases of Aging at the Philadelphia College of Osteopathic Medicine (PA, USA). "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.”

The researchers want to arrange clinical trials in patients with late-onset AD to investigate the effect of typical antibiotics used for treating C pneumoniae infections. However, they note there is controversy whether any existing antibiotics for C pneumoniae can truly clear the organism from the human body. "But in reality we are not sure whether the antibiotic approach will be sufficient to actually eradicate the infection. 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.”

Although AD was thought to be a hereditary disease, research has shown that only 2-5% of cases have a tie to genetic mutations. Of all the people who reach the age of 85, about 50% will develop AD.




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