Distribution of Porphyromonas gingivalis fimA genotypes in cardiovascular specimens from Japanese patients

"Gum bug, leave my heart alone!"--epidemiologic and mechanistic evidence linking periodontal infections and atherosclerosis

Evidence from epidemiologic studies suggests that periodontal infections are independently associated with subclinical and clinical atherosclerotic vascular disease. Although the strength of the reported associations is modest, the consistency of the data across diverse populations and a variety of exposure and outcome variables suggests that the findings are not spurious or attributable only to the effects of confounders. Analysis of limited data from interventional studies suggests that periodontal treatment generally results in favorable effects on subclinical markers of atherosclerosis, although such analysis also indicates considerable heterogeneity in responses. Experimental mechanistic in vitro and in vivo studies have established the plausibility of a link between periodontal infections and atherogenesis, and have identified biological pathways by which these effects may be mediated. However, the utilized models are mostly mono-infections of host cells by a limited number of 'model' periodontal pathogens, and therefore may not adequately portray human periodontitis as a polymicrobial, biofilm-mediated disease. Future research must identify in vivo pathways in humans that may (i) lead to periodontitis-induced atherogenesis, or (ii) result in treatment-induced reduction of atherosclerosis risk. Data from these studies will be essential for determining whether periodontal interventions have a role in the primary or secondary prevention of atherosclerosis.

Distribution of Porphyromonas gingivalis fimA genotypes in primary endodontic infections

OBJECTIVE

Long fimbriae (FimA) are important virulence factors of Porphyromonas gingivalis. Based on the diversity of the fimA gene, this species is classified into 6 genotypes. This study surveyed samples from primary endodontic infections for the presence of these P. gingivalis fimA variants.

STUDY DESIGN

Genomic DNA isolated from samples taken from 25 root canals of teeth with chronic apical periodontitis and 25 aspirates from acute apical abscess was used as template in polymerase chain reaction (PCR) assays directed toward the detection of the different P. gingivalis fimA genotypes.

RESULTS

Porphyromonas gingivalis was detected by a 16S rRNA gene-based PCR in 36% of the total number of cases sampled (44% of chronic apical periodontitis and 28% of abscess aspirates). In cases of chronic apical periodontitis, P. gingivalis variant type IV was the most prevalent (24%), followed by types I (20%), II (16%), and III (8%). In acute abscess samples, variant type II was the most prevalent (12%), followed by types III and IV (8% of each) and type I (4%). Combinations of up to 3 different genotypes were detected in a few cases. No single fimA genotype variant or combination thereof was significantly associated with symptoms. Overall, fimA types IV (16%), II (14%), and I (12%) were the most prevalent.

CONCLUSIONS

Findings demonstrated that different P. gingivalis fimA genotypes can be present in primary endodontic infections.

High Antibody Levels to P. gingivalis in Cardiovascular Disease

Recent evidence suggests that strain variation in the serum IgG response to Porphyromonas gingivalis occurs in periodontal disease and cardiovascular disease (CVD). This study aimed to test the hypothesis that different P. gingivalis strains would elicit different levels of IgG, depending on a patient’s cardiovascular (CV) and periodontal health. For CVD patients, serum antibody levels increased significantly with increasing numbers of deep pockets for all strains of P. gingivalis, except W50 (p < 0.001). We used a two-way analysis of variance to examine differences in antibody responses across several CV and periodontal groups simultaneously. There was a significant interaction effect (p < 0.05) between periodontal status and CV status for antibody levels to ATCC33277, UQD605, and Su63. This study shows variation in strain type with respect to serum IgG response in several CV and periodontal categories, providing further support for the role of the immune response to P. gingivalis in the relationship between periodontal disease and CVD.

Lipoproteins and lipoprotein metabolism in periodontal disease

A growing body of evidence indicates that the incidence of atherosclerosis is increased in subjects with periodontitis - a chronic infection of the oral cavity. This article summarizes the evidence that suggests periodontitis shifts the lipoprotein profile to be more proatherogenic. LDL-C is elevated in periodontitis and most studies indicate that triglyceride levels are also increased. By contrast, antiatherogenic HDL tends to be low in periodontitis. Periodontal therapy tends to shift lipoprotein levels to a healthier profile and also reduces subclinical indices of atherosclerosis. In summary, periodontal disease alters lipoprotein metabolism in ways that could promote atherosclerosis and cardiovascular disease.

Roles of oral bacteria in cardiovascular diseases--from molecular mechanisms to clinical cases: Involvement of Porphyromonas gingivalis in the development of human aortic aneurysm

Accumulating evidence suggests the involvement of Porphyromonas gingivalis (P. gingivalis), a periodontal pathogen, in cardiovascular diseases. Clinical specimens of aneurysmal tissue and dental plaque collected from patients infected with or without P. gingivalis were analyzed. The number of aneurysms in the distal aorta in the P. gingivalis-infected group was significantly higher than that in the non-infected group. Cellular accumulation of adipocytes in aneurysms was less frequently identified in the infected group. The expression of embryonic myosin heavy chain isoform, a phenotypic marker for proliferative smooth muscle cells, was higher in the P. gingivalis-infected group than the non-infected group. Clinical and histopathological features of aortic aneurysms associated with P. gingivalis infection are different from those present in non-infected patients. The major characteristic of P. gingivalis infection associated with aneurysms is smooth muscle cell proliferation in the distal aorta.

Monoclonal antibodies produced against lipopolysaccharide from fimA Type II Porphyromonas gingivalis

An important periodontal pathogen, Porphyromans gingivalis strains are classified into six genotypes (types I-V and Ib), based on the genotype of the fimbriae A (fimA). Among the genotypes, fimA type II strains are thought to be most strongly related to advanced periodontitis. To develop passive immunotherapy, over 300 hybridoma clones were constructed through immunization of cell extracts of fimA type II strain P. gingivalis TDC60 using hybridoma technology. Among these clones, 15 MAbs recognized TDC60 lipopolysaccharide (LPS) with an individual ladder-like structure by Western blot analysis. Further Western blotting of the 15 MAbs against LPS from TDC60, FDC381 (fimA type I), and W83 (fimA type IV) of P. gingivalis and Escherichia coli was carried out. None of these MAbs recognized E. coli LPS, and divided into at least three different Western blot patterns. To confirm the specificity to LPS, three clones were selected and competition assays were carried out using TDC60 LPS. All three MAbs reduced the reactivity against TDC60 LPS after absorption of the LPS in a dose-dependent manner. These findings suggest that MAbs recognizing different epitopes of P. gingivalis LPS were successfully constructed, and these MAbs may be useful in neutralizing P. gingivalis infection.

Quantification of Porphyromonas gingivalis and fimA genotypes in smoker chronic periodontitis

AIM

Porphyromonas gingivalis fimA genotypes were associated with virulence factors in vitro, but little evidence of an association with disease severity were shown in humans. We aimed to correlate levels of P. gingivalis fimA genotypes II and IV and probing depth in smoker-chronic periodontitis subjects.

MATERIAL AND METHODS

One hundred and sixty eight subgingival samples of 20 smokers non-treated chronic periodontitis subjects obtained from sites with different probing depths [shallow (< or =3 mm), intermediate (4-6 mm), deep (> or =7 mm)] were analysed by real-time PCR for P. gingivalis and genotypes fimA II and IV.

RESULTS

P. gingivalis and fimA IV were detected in all subjects, whereas fimA II was detected in 18 subjects (90%). One hundred and fifty two sites (90.5%) harboured P. gingivalis. Genotypes II and IV were detected in 28% and 69.6% of sites, respectively. The proportions of genotypes II and IV in relation to P. gingivalis levels were similar in shallow, intermediate and deep probing sites (2.4%, 4.6%, 1.4% for genotype II and 15.5%, 17.7%, 11.7% for genotype IV, respectively), indicating that other non-tested genotypes were more abundant. Increased levels of genotype IV were associated with increasing probing depth, but not of genotype II.

CONCLUSIONS

The data suggested an association between P. gingivalis genotype fimA IV and disease severity in smoker-chronic periodontitis subjects.

Quantitative detection of periodontopathic bacteria in atherosclerotic plaques from coronary arteries

Oral pathogens, including periodontopathic bacteria, are thought to be aetiological factors in the development of cardiovascular disease. In this study, the presence of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum-periodonticum-simiae group, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Tannerella forsythia in atheromatous plaques from coronary arteries was determined by real-time PCR. Forty-four patients displaying cardiovascular disease were submitted to periodontal examination and endarterectomy of coronary arteries. Approximately 60-100 mg atherosclerotic tissue was removed surgically and DNA was obtained. Quantitative detection of periodontopathic bacteria was performed using universal and species-specific TaqMan probe/primer sets. Total bacterial and periodontopathic bacterial DNA were found in 94.9 and 92.3 %, respectively, of the atheromatous plaques from periodontitis patients, and in 80.0 and 20.0 %, respectively, of atherosclerotic tissues from periodontally healthy subjects. All periodontal bacteria except for the F. nucleatum-periodonticum-simiae group were detected, and their DNA represented 47.3 % of the total bacterial DNA obtained from periodontitis patients. Porphyromonas gingivalis, A. actinomycetemcomitans and Prevotella intermedia were detected most often. The presence of two or more periodontal species could be observed in 64.1 % of the samples. In addition, even in samples in which a single periodontal species was detected, additional unidentified microbial DNA could be observed. The significant number of periodontopathic bacterial DNA species in atherosclerotic tissue samples from patients with periodontitis suggests that the presence of these micro-organisms in coronary lesions is not coincidental and that they may in fact contribute to the development of vascular diseases.

Periodontal disease and risk of atherosclerotic coronary heart disease

Atherosclerosis is an important component of coronary heart disease (CHD), which is the leading cause of death worldwide, including in Japan. Because atherosclerotic processes are typified by chronic inflammatory responses, which are similar to those elicited by chronic infection, the role of infection in promoting or accelerating atherosclerosis has received considerable focus. Increasing evidence supports the notion that periodontitis is associated with increased risk of atherosclerosis through dysfunction of endothelial cells induced by either periodontopathic bacteria or their products, or inflammatory mediators derived from infected periodontal tissue. Here we review whether periodontitis represents a risk factor for CHD or atherosclerosis, particularly in a Japanese population.