Written by Joyce Smith, BS. This study demonstrates how an oral infection with P. ginivalis can lead to chronic periodontal disease and the development and progression of atherosclerotic vascular disease.
Atherosclerotic vascular disease (ASVD), the leading cause of death in the united Stated, inflicts one third of all Americans; yet one- half of them have no demonstrable risk factors for the disease 1. Although no causal relationship between periodontal disease (PD) and AVSD has been proven, studies have demonstrated the presence of periodontal bacteria in the arterial plaque in humans. In particular, the oral gram-negative bacterium, P. gingivalis (Porphyromonas gingivalis), has been isolated from samples of human arterial plaque, thus demonstrating its ability to replicate.
To examine the role of these bacteria in the development and progression of atherosclerotic plaque, researchers in this study infected twenty-four Apo null mice with P. gingivalis cells while 24 control mice were infection free. Mice were euthanized at 12 and 24 weeks and blood and tissue samples were collected for analyses.
Chronic infection with P. gingivalis cells produced the following classical PD symptoms in the 12-week and 24-week infected mice:
- Significant alveolar bone resorption 2 occurred relative to control mice at 12 and 24 weeks of infection (P<0.001)
- Demonstrates that chronic oral infection with P. gingivalis induced PD in mice as evidenced by active tissue invasion
- Both 12- and 24-week infected mice had significantly higher levels of P. gingivalis -specific IgG relative to controls (P<0.05) while only 24 week-infected mice had significantly higher levels of IgM relative to controls. (P<0.01)
- Demonstrates a systemic humoral immune response to P. gingivalis-induced PD
- P. gingivalis genomic DNA was found in the hearts and aorta of 12-week and in the hearts, aorta, liver, spleen and kidneys of the 24-week- infected mice
- Demonstrates that P. gingivalis has the ability to spread from the mouth to the body organs
- Aorta cross sections of the 12-week and 24-week infected mice, when examined histologically, had significantly greater aortic plaque relative to the infection-free control mice (P<0.05 and P<0.01 respectively)
- Demonstrates invasion of the aorta and the development and progression of atherosclerotic plaque
- VLDL (very low-density lipoprotein), LDL (low-density lipoprotein), HDL (high-density lipoprotein), and oxidized LDL in serum of 24-week-infected mice were significantly higher than in controls (P<0.01). Infected mice also had significantly elevated levels of serum amyloid A and significantly reduced serum nitric oxide relative to control mice (P< 0.05)
- Demonstrates that P. gingivalis infection increased the systemic risk factors for atherosclerosis
Researchers believe this study is the first to demonstrate a causal association between the role of P. gingivalis-induced chronic periodontal disease and the formation of atherosclerotic plaque formation in an Apo null mouse model.
Source: Velsko IM, Chukkapalli SS, Rivera MF, Lee J-Y, Chen H, Zheng D, et al. (2014) Active Invasion of Oral and Aortic Tissues by Porphyromonas gingivalis in Mice Causally Links Periodontitis and Atherosclerosis. PLoS ONE 9(5): e97811. https://doi.org/10.1371/journal.pone.0097811
© 2014 Velsko et al. This is an open-access article distributed under the terms of the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Posted March 13, 2018.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
References:
- Lockhart PB, Bolger AF, Papapanou PN, et al. Periodontal disease and atherosclerotic vascular disease: does the evidence support an independent association?: a scientific statement from the American Heart Association. Circulation. 2012;125(20):2520-2544.
- Verma R, Bhattacharyya I, Sevilla A, et al. Virulence of major periodontal pathogens and lack of humoral immune protection in a rat model of periodontal disease. Oral diseases. 2010;16(7):686-695.
