How Do Periodontal Pathogens Contribute to Atherosclerosis?

HELSINKI, FINLAND -- June 12, 2007 -- Periodontitis and periodontal pathogens raise the risk of atherosclerosis and cardiovascular diseases (CVD) events through an increase in serum lipopolysaccharide (LPS), according to new research presented here at the 76th Congress of the European Atherosclerosis Society (EAS).


Periodontitis, an infection in tooth-supporting tissues, is recognised as an independent risk factor for CVD. However, the exact mechanism behind the association between periodontitis and CVD is not known.


"One of the basic hypotheses behind the mechanism for the association between periodontitis and CVD is endotoxemia caused by gram-negative periodontal pathogens, since they have an open access to circulation through bleeding gums," said lead investigator Pirkko Pussinen, PhD, adjunct professor, Institute of Dentistry, University of Helsinki, Helsinki, Finland.


LPS in the circulation is a potent activator of inflammatory cells leading to macrophage-derived foam cell formation, a hallmark of early atherosclerosis, and it has been hypothesised that an increase in serum LPS concentration might mediate the association between periodontitis and CVD, Dr. Pussinen explained. "However, this hypothesis has not been tested before," she said.


To investigate the association between the risk of incident CVD events and serum antibody levels to major periodontal pathogens, as well as total LPS concentration and various inflammatory markers, Dr. Pussinen and colleagues conducted a prospective case-cohort study involving a cohort of 6,051 people between 25 and 64 years of age, with a median follow-up of 10 years. During that time, 189 incident CVD events occurred. A stratified random sample (n=320) of the original cohort served as control.


The researchers found that a high combined antibody response to periodontal pathogens independently predicted incident CVD events, and high LPS concentration was also associated with increased CVD risk.


These results suggest that systemic exposure to periodontal pathogens or LPS induces systemic inflammation leading to increased risk for CVD, the researchers concluded. "We've also found that endotoxemia is especially harmful for subjects with a low HDL cholesterol concentration," Dr. Pussinen noted.


In view of these data, it is very important that practising clinicians pay attention to the oral health of their patients and refer them to see a dentist regularly, Dr. Pussinen suggested.