Hidden Source Of Alzheimer’s May Lie Outside Brain, Study Finds
Joe Lombardi
Alzheimer’s disease, long seen as a disorder of the aging brain, may actually begin in an unexpected place: the mouth
Sept. 13, 2025 (Daily Voice) – Researchers reported evidence that a bacterium commonly associated with chronic gum disease could play a direct role in the development of Alzheimer’s.
The study, published in Science Advances, details how Porphyromonas gingivalis, the pathogen behind periodontitis, was detected in the brains of Alzheimer’s patients.
The findings come from an international team of scientists that included Jan Potempa, a microbiologist at the University of Louisville.
Potempa said the research offers some of the strongest evidence yet linking gum infection to Alzheimer’s pathology, though he stressed more work is needed to prove causation.
In animal studies, the team found that oral infection with P. gingivalis led to brain colonization.
It also triggered production of amyloid beta, a sticky protein fragment that forms the plaques widely recognized as a hallmark of Alzheimer’s disease.
Researchers also identified toxic enzymes produced by the bacterium, called gingipains, in neurons of Alzheimer’s patients.
The higher the gingipain levels, the greater the buildup of proteins linked to brain cell damage.
The study also explored a potential treatment pathway. By using a small-molecule drug to block gingipains, researchers reported reduced bacterial load, less amyloid beta production, and protection of neurons in the hi
Potempa noted that while the work opens the door to new therapeutic strategies, it also reinforces a simpler message: oral health could be more closely tied to brain health than previously understood.