0125 GMT February 17, 2019
Researchers at the University of Illinois at Chicago studied the effects of periodontal disease, a common but preventable gum infection, with Alzheimer's, which currently has no treatment or cure. The findings were published in PLOS One, UPI reported.
"This was a big surprise," corresponding author Dr. Keiko Watanabe, a professor of periodontics at the UIC College of Dentistry, said in a press release. "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."
Watanabe noted other studies found 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."
In the study, researchers established chronic periodontitis, which is characterized by soft tissue damage and bone loss in the oral cavity, in 10 mice. Another 10 mice served as the control group.
After 22 weeks of repeated oral application of the bacteria, the researchers studied the brain tissue of the mice and compared brain health.
Mice chronically exposed to the bacteria had significantly higher amounts of accumulated amyloid beta as well as more brain inflammation and fewer intact neurons because of degeneration.
Amyloid beta protein and RNA analyses also displayed greater expression of genes associated with inflammation and degeneration in the study group. In addition, DNA from the periodontal bacteria was also found in the brain tissue of mice and a bacterial protein was observed inside their neurons in the study group.
"Our data not only demonstrate the movement of bacteria from the mouth to the brain, but also that chronic infection leads to neural effects similar to Alzheimer's," Watanabe said.