Long-term exposure to periodontal disease bacteria causes inflammation and degeneration of brain neurons in mice that is similar to the effects of Alzheimer’s disease in humans, according to a new study from researchers at the University of Illinois at Chicago (UIC).
The findings, which are published in PLOS ONE, suggest that periodontal disease may be an initiator of Alzheimer’s.
Dr Keiko Watanabe, corresponding author on the study said: “Other studies have demonstrated a close association between periodontitis and cognitive impairment, but this is the first study to show that exposure to the periodontal bacteria results in the formation of senile plaques that accelerate the development of neuropathology found in Alzheimer’s patients.
“This was a big surprise. We did not expect that the periodontal pathogen would have this much influence on the brain, or that the effects would so thoroughly resemble Alzheimer’s disease.”
To study the impact of the bacteria on brain health, Watanabe and her colleagues established chronic periodontitis in 10 wild-type mice. Another 10 mice served as the control group. After 22 weeks of repeated oral application of the bacteria to the study group, the researchers studied the brain tissue of the mice and compared brain health.
The researchers found that the mice chronically exposed to the bacteria had significantly higher amounts of accumulated amyloid beta – a senile plaque found in the brain tissue of Alzheimer’s patients. The study group also had more brain inflammation and fewer intact neurons due to degeneration.
Watanabe said: “Oral hygiene is an important predictor of disease, including diseases that happen outside the mouth”.