Immunoglobulin G antibodies against Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans in cardiovascular disease and periodontitis

Abstract

Objectives: The aim was to elucidate whether levels of circulating antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis correlate to loss of attachment, as a marker for periodontitis and cardiovascular disease (CVD). Design: Sera were collected from 576 participants of the Danish Health Examination Survey (DANHES). Immunoglobulin G antibodies against lipopolysaccharide (LPS) and protein antigens from the a, b and c serotypes of A. actinomycetemcomitans and P. gingivalis were quantified by titration in ELISA plates coated with a mixture of antigens prepared by disintegration of bacteria. Results: Levels of antibodies against P. gingivalis (OR = 1.48) and A. actinomycetemcomitans (1.31) associated with periodontitis, as determined by univariable logistic regression analysis. These antibody levels also associated with CVD (1.17 and 1.37), respectively, However, after adjusting for other risk factors, including age, smoking, gender, alcohol consumption, overweight, and level of education using multivariable logistic regression analysis, only increasing body mass index (BMI; 1.09), previous smoking (1.99), and increasing age (decades) (2.27) remained associated with CVD. Increased levels of antibodies against P. gingivalis (1.34) remained associated with periodontitis after adjusting for other risk factors. Conclusions: CVD and periodontitis were associated with levels of IgG antibodies to P. gingivalis or A. actinomycetemcomitans in univariable analyses, but only the association of P. gingivalis antibody levels with periodontitis reached statistical significance after adjustment for common confounders. Age, in particular, influenced this relationship.

Keywords: Cardiovascular disease; antibody; atherosclerosis; cohort study; hypertension; immunoglobulin; myocardial infarction; periodontal disease; periodontitis; risk factor.

Figure 1.

Analysis of antigen preparations from A. actinomycetemcomitans (A.a.) and P. gingivalis (P.g.) as used for coating of ELISA plates. Lanes of sodium dodecyl sulfate polyacrylamide (7%) gels were loaded with amounts of antigens equal to those used for coating of one 96-well plate. Staining with Coomassie Blue (polysaccharides and LPS) are not visible. M_r markers in kilo Daltons.

Figure 2.

Validation of assay sensitivity and specificity to antigen preparations from A. actinomycetemcomitans. A) Homologous titration curves for serum from a patient with aggressive periodontitis colonized with the JP2 clone (serotype b) of A. actinomycetemcomitans in wells saturated with disintegrated serotype b bacterial antigen (●) and whole, formalin-treated serotype b bacteria (■), respectively. B) Comparative titration of sera from four microbiologically and clinically characterized individuals in an ELISA plate coated with an equivalent mixture of antigens from three strains of A. actinomycetemcomitans representing serotypes a, b, and c. The four sera were from a patient with aggressive periodontitis colonized with the JP2 clone of A. actinomycetemcomitans (●), a healthy individual colonized by a non-JP2 clone of A. a. (∎), two healthy individuals without detectable A.a. (▲,▼). C) Comparative titrations of a serum from a patient with aggressive periodontitis colonized with the JP2 clone (serotype b) of A. actinomycetemcomitans in ELISA wells coated with antigens from either A. actinomycetemcomitans serotype b (●), serotype a (∎), or serotype c (▲).