Common oral pathogen found to increase heart attack damage

Dental Tribune International

Mon. 23. October 2023

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TOKYO, Japan: Researchers from Tokyo Medical and Dental University have added to the literature linking periodontal disease and cardiovascular disease by confirming that the oral pathogen Porphyromonas gingivalis increases damage from myocardial infarction. The pathogen is found in 86% of chronic periodontal disease samples, and the researchers say that treating the disease could help to reduce the risk of deadly cardiovascular events.

Dr Yuka Shiheido-Watanabe, lead author of the study, said in a university press release that P. gingivalis has been shown to “exacerbate post-infarction myocardial fragility”, but “[the] mechanisms underlying this effect remained unknown”.

The researchers engineered a P. gingivalis variant without gingipain—a key virulence factor known to hinder programmed cell death—and used the bacterium to infect rat cardiac muscle cells and mice.

“The results were very clear,” commented co-author Dr Yasuhiro Maejima. “The viability of cells infected with the mutant bacterium lacking gingipain was much higher than that of cells infected with the wild-type bacterium. In addition, the effects of myocardial infarction were significantly more severe in mice infected with wild-type P. gingivalis than in those infected with the mutant P. gingivalis lacking gingipain,” Dr Maejima explained.

“Our findings suggest that infection with P. gingivalis producing gingipain results in excessive autophagosome accumulation, which can lead to cellular dysfunction, cell death, and ultimately cardiac rupture,” Dr Shiheido-Watanabe concluded.

Periodontal disease affects over 50% of adults and ranks as the sixth most common disease globally. The disease has been linked to systemic diseases like rheumatoid arthritis and Alzheimer’s disease, and its connection with cardiovascular disease has been the subject of increasing research.

The study, titled “Porphyromonas gingivalis, a periodontal pathogen, impairs post-infarcted myocardium by inhibiting autophagosome–lysosome fusion”, was published on 18 September 2023 in the International Journal of Oral Science.