Is the observed association between periodontitis and atherosclerosis causal?

The Effects of Porphyromonas gingivalis on Atherosclerosis-Related Cells

Atherosclerosis (AS), one of the most common types of cardiovascular disease, has initially been attributed to the accumulation of fats and fibrous materials. However, more and more researchers regarded it as a chronic inflammatory disease nowadays. Infective disease, such as periodontitis, is related to the risk of atherosclerosis. Porphyromonas gingivalis (P. gingivalis), one of the most common bacteria in stomatology, is usually discovered in atherosclerotic plaque in patients. Furthermore, it was reported that P. gingivalis can promote the progression of atherosclerosis. Elucidating the underlying mechanisms of P. gingivalis in atherosclerosis attracted attention, which is thought to be crucial to the therapy of atherosclerosis. Nevertheless, the pathogenesis of atherosclerosis is much complicated, and many kinds of cells participate in it. By summarizing existing studies, we find that P. gingivalis can influence the function of many cells in atherosclerosis. It can induce the dysfunction of endothelium, promote the formation of foam cells as well as the proliferation and calcification of vascular smooth muscle cells, and lead to the imbalance of regulatory T cells (Tregs) and T helper (Th) cells, ultimately promoting the occurrence and development of atherosclerosis. This article summarizes the specific mechanism of atherosclerosis caused by P. gingivalis. It sorts out the interaction between P. gingivalis and AS-related cells, which provides a new perspective for us to prevent or slow down the occurrence and development of AS by inhibiting periodontal pathogens.

Changes in the Biomarkers of Oxidative/Nitrosative Stress and Endothelial Dysfunction Are Associated with Cardiovascular Risk in Periodontitis Patients

Patients with cardiovascular disease (CVD) and periodontitis (PT) show shared risk factors as result of the altered molecular mechanisms associated with pathological conditions. The aim of our study was to evaluate if the plasma biomarkers associated with endothelial dysfunction may also be related to alterations in the inflammatory status in peripheral blood mononuclear cells (PBMC). Patients with PT, coronary heart disease (CHD), or both diseases as well as controls were enrolled. Plasma levels of coenzyme Q10 (CoQ10), 3-nitrotyrosine (NT), and asymmetric dimethylarginine (ADMA) were assessed using HPLC. mRNA levels of caspase-1 (CASP1), NLR family pyrin domain containing 3 (NLRP3), and tumor necrosis factor-α (TNF-α) in PBMC from the recruited subjects were quantified using real-time PCR. Patients with PT + CHD showed lower CoQ10 plasma levels and increased concentrations of NT in comparison to healthy subjects. ADMA levels were higher in CHD and PT + CHD patients compared to controls. Transcript levels of CASP1, NLRP3, and TNF-α were up-regulated in PBMC from all patient groups when compared to healthy subjects. Our results suggest a possible causal link between oxidative stress, high levels of NT and ADMA, and inflammasome activation, which may be involved in the endothelial inflammatory dysfunction leading to the pathogenesis and progression of CHD in PT patients.

Periodontal health and detection of periodontal bacteria in patients with acute coronary syndrome

Introduction: Recent studies have found that patients with periodontitis have greater risk of incurring fatal cardiovascular disease than patients without periodontitis. Emerging research has identified inflammation caused by periodontitis as significantly increasing the risk for ACS. Aim: The aim of this study was to investigate a periodontal status in the patients with ACS, and to assess the association of different periodontal parameters with ACS. Material and methods: In the first group, patients both with ACS and periodontitis were enrolled as cases. Patients were examined 3 days after ischemia. The second group consisted of patients who had only periodontitis. The control group consisted of healthy individuals. Periodontal parameters were measured and matched on the basis of demographic characteristics and assessed between the groups. The severity of periodontitis in both cases was analyzed. Results: Analysis of the periodontal parameters showed that median scores were higher in patients in the first and the second group compared to the third control group but significantly higher in group with ACS. Levels of inflammatory markers were highest in the first group, compared to the second group and the control group. Periodontal pathogens were more strongly present in patients with ACS than in the group with periodontitis, indicating that it was a serious illness in these patients. Conclusion: This study supports an association between periodontitis and ACS. Severe periodontitis is present in this patients indicating that periodontitis can further act on the development of ACS.

Oral Healthcare and Cardiovascular Disease: A Scoping Review of Current Strategies and Implications for Nurses

BACKGROUND

There is epidemiological evidence showing an association between periodontal disease and cardiovascular disease (CVD). Despite this evidence* no comprehensive review has been undertaken to identify strategies to improve the oral health of people with CVD.

OBJECTIVES

The aim of this review is to identify current evidence relating to the oral healthcare and management of patients with CVD.

METHODS

A scoping review was undertaken focusing on 4 key areas, namely, the impact of periodontal treatment on CVD, current recommendations regarding oral health and CVD, the role of nurses in promoting oral health, and available resources to support them. Databases were searched using a combination of keywords and search terms and 34 articles were selected.

RESULTS

Systematic reviews suggest that periodontal treatment may improve CVD outcomes by reducing systemic inflammation and improving endothelial function. However, there is insufficient evidence to confirm or refute these findings. International guidelines recognize the link between periodontal disease and CVD and recommend preventative strategies in this area. Non-oral health professionals, including nurses, can promote oral health and have been undertaking this role in areas like aged care and pregnancy. However, this aspect of nursing care has not been explored in the cardiac setting and no relevant training and assessment tools are available.

CONCLUSIONS

Maintaining oral health among cardiovascular patients is important, yet it appears to be neglected during cardiac care. Cardiac nurses are in an excellent position to promote oral health but further research is required to define their role and develop supporting resources.

Poor oral health and coronary artery disease: a case-control study

BACKGROUND

There is insufficient research on the relationship of oral health and coronary artery disease (CAD) from developing countries, such as Pakistan. This study observes the status of oral health in the CAD population.

METHODS

A case-control study was conducted on 145 cases and 145 controls. Otherwise healthy patients with CAD (cases) and individuals free from previous/current history of CAD (controls), having ≥14 remaining teeth, were examined for oral health status through missing teeth, plaque index (PI), and community periodontal index (CPI). Student t test, χ2 test, and multivariate regression analysis were applied at significance level of 95% (P ≤ 0.05) to compare study parameters between cases and controls.

RESULTS

A significant difference between cases and controls was observed in this study sample with respect to missing teeth (P = 0.027) and periodontal parameters of PI and CPI (P < 0.001). Cases were observed with significantly higher scores of PI (2 and 3) and CPI (3 and 4) compared with controls. Prevalence of periodontal parameters was observed to be higher in cases than controls at subgroup-level (sex and age group) analysis. A significant odds ratio (OR), unadjusted, between CAD and periodontal indicators of PI (mild to severe plaque/no plaque: OR = 5.04, 95% confidence interval [95% CI] = 2.24 to 11.36) and CPI (healthy/poor periodontal status: OR = 4.59, 95% CI = 1.81 to 11.61) scores was noted; cases were at odds of 1.20 (95% CI = 0.93 to 15.68, P = 0.017) for having poor oral health after adjusting age, sex, and education.

CONCLUSION

Poor oral health was significantly associated with CAD in this study sample matched for sociodemographic characteristics.

Potentially modifiable risk factors for dementia in identical twins

BACKGROUND

The purpose of this study was to test nongenetic factors that might explain discordance for dementia in monozygotic twin pairs. Risk factors included education, engaged lifestyle in midlife, and early life circumstances indexed by tooth loss, short adult height, and parental social class.

METHODS

Data are from the HARMONY study, including members of the Swedish Twin Registry age 65 and older and alive in 1998, who were screened and assessed clinically for dementia. Analyses included a case-control design to evaluate the risk factors and a co-twin control design that permits testing nongenetic risk factors while controlling for genetic influences. Case-control analyses included 310 dementia cases and 3,063 nondemented controls. There were 106 monozygotic twin pairs discordant for dementia. Risk factors were assessed independently by the Swedish Twin Registry three decades previously.

RESULTS

Case-control findings showed that history of tooth loss before age 35 and low educational attainment were significant risk factors for Alzheimer's disease, with short adult height also contributing to risk for total dementia. In co-twin control analyses, only history of tooth loss before age 35 was a significant risk factor for Alzheimer's disease, whereas low educational attainment also contributed to risk for total dementia and lack of physical exercise to risk for non-Alzheimer's dementias.

CONCLUSIONS

Potentially modifiable risk factors from early and midlife, with a cumulative detrimental effect on the brain, contribute to risk of dementia. Based on the association with tooth loss, further investigation of inflammatory load as a risk factor for Alzheimer's disease is warranted.

Microbiologic Analysis of Periodontal Pockets and Carotid Atheromatous Plaques in Advanced Chronic Periodontitis Patients

BACKGROUND

In recent years, many researchers have focused their attention on the ability of periodontal pathogens to colonize atheromatous plaques. Nevertheless, a clear correlation between the detection rates of periodontopathic bacterial DNA in atheromas and in subgingival plaque samples has not been established. The aim of our study was to assess the presence of five periodontal pathogens (Actinobacillus actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia [formerly Tannerella forsythensis]) in periodontal pockets and in carotid atheromas recovered from the same patients.

METHODS

Thirty-three patients with advanced chronic periodontitis scheduled for endarterectomy were enrolled in the study. DNA was extracted from subgingival plaque samples and carotid atheromas. Universal bacteria primers for general detection of bacteria and species-specific primers for detection of periodontal pathogens were used to amplify part of the 16S rRNA gene by polymerase chain reaction.

RESULTS

All subgingival plaque samples were positive for at least one target microorganism. The prevalence of T. forsythia, P. gingivalis, T. denticola, P. intermedia, and A. actinomycetemcomitans were 69.7%, 63.6%, 54.5%, 45.4%, and 33.3%, respectively. Bacterial DNA was detected in 31 out of 33 endarterectomy specimens. However, none of the samples tested positive for DNA from periodontal pathogens.

CONCLUSION

The presence of periodontal bacteria in atheromatous plaques was not confirmed by this investigation; thus, no correlation could be drawn between periodontitis bacteria and microorganisms involved in the atherosclerotic lesions.

Fimbria-dependent activation of pro-inflammatory molecules in Porphyromonas gingivalis infected human aortic endothelial cells

Epidemiological studies support that chronic periodontal infections are associated with an increased risk of cardiovascular disease. Previously, we reported that the periodontal pathogen Porphyromonas gingivalis accelerated atherosclerotic plaque formation in hyperlipidemic apoE-/- mice, while an isogenic fimbria-deficient (FimA-) mutant did not. In this study, we utilized 41 kDa (major) and 67 kDa (minor) fimbria mutants to demonstrate that major fimbria are required for efficient P. gingivalis invasion of human aortic endothelial cells (HAEC). Enzyme-linked immunosorbent assay (ELISA) revealed that only invasive P. gingivalis strains induced HAEC production of pro-inflammatory molecules interleukin (IL)-1beta, IL-8, monocyte chemoattractant protein (MCP)-1, intracellular adhesion molecule (ICAM)-1, vascular cellular adhesion molecule (VCAM)-1 and E-selectin. The purified native forms of major and minor fimbria induced chemokine and adhesion molecule expression similar to invasive P. gingivalis, but failed to elicit IL-1beta production. In addition, the major and minor fimbria-mediated production of MCP-1 and IL-8 was inhibited in a dose-dependent manner by P. gingivalis lipopolysaccharide (LPS). Both P. gingivalis LPS and heat-killed organisms failed to stimulate HAEC. Treatment of endothelial cells with cytochalasin D abolished the observed pro-inflammatory MCP-1 and IL-8 response to invasive P. gingivalis and both purified fimbria, but did not affect P. gingivalis induction of IL-1beta. These results suggest that major and minor fimbria elicit chemokine production in HAEC through actin cytoskeletal rearrangements; however, induction of IL-1beta appears to occur via a separate mechanism. Collectively, these data support that invasive P. gingivalis and fimbria stimulate endothelial cell activation, a necessary initial event in the development of atherogenesis.

Isolation and identification of hydroxyl-platelet-activating factor from natural sources

Platelet-activating factor (PAF), a potent inflammatory mediator that has previously been detected in elevated levels in inflamed gingival tissues, in gingival crevicular fluid (GCF) and in saliva, is implicated in periodontal disease. The biologically active phospholipid detected in gingival crevicular fluid is a hydroxyl-PAF analogue. In a preliminary study this bioactive molecule was detected for the first time in human blood derived from volunteers with chronic periodontitis as well as from periodontally healthy volunteers. Compounds isolated from natural sources as well as synthetic ones have been reported as biologically active lipids with physiological importance based on the fact that they induce platelet aggregation with EC50 values ranging from 100 to 0.01 microM through interaction with G-protein-coupled receptors like the PAF receptor, leading to altered signal transduction. In this study, the existence of hydroxyl-PAF analogue in human blood was further studied as well as its distribution in plasma and in blood components. The existence of hydroxyl-PAF analogue was also investigated in samples from rabbit blood hen's egg yolk. The hydroxyl-PAF analogue was purified by high-performance liquid chromatography, detected by biological assays and identified by electrospray MS analysis. Quantitative determination of PAF and hydroxyl-PAF analogue (expressed as PAF-like activity) showed a statistically significant increase in the ratio of plasma hydroxyl-PAF analogue levels to plasma PAF levels in volunteers with periodontitis. Moreover, hydroxyl-PAF analogue was also detected in rabbit blood and hen's egg yolk samples. These data support that this bioactive lipid may play a role in oral inflammation and suggest PAF as a member of a lipid molecule family with different structures and from different sources which share the same or similar biological activities, apparently with different physiological roles in human and animals.

Sensitization of human aortic endothelial cells to lipopolysaccharide via regulation of Toll-like receptor 4 by bacterial fimbria-dependent invasion

Toll-like receptors (TLRs) are differentially up-regulated in response to microbial infection and chronic inflammatory diseases such as atherosclerosis. Epidemiological data support the idea that periodontal disease may be a risk factor for acceleration of atherosclerosis. Porphyromonas gingivalis, the etiological agent of periodontal disease, invades endothelium, has been detected in human atheromatous tissue, and accelerates atheroma formation in apolipoprotein E-/- mice with concurrent induction of TLRs in the aorta. As endothelial cells can present antigen via TLRs and play an important role in the development of atherosclerosis, we examined TLR expression in human aortic endothelial cells (HAEC) cultured with wild-type P. gingivalis, a fimbria-deficient mutant, and purified antigens. We observed increased TLR expression in HAEC infected with wild-type P. gingivalis by fluorescence-activated cell sorter, but not with noninvasive, fimbria-deficient mutant or purified P. gingivalis antigens. Following a wild-type P. gingivalis challenge, functional TLR2 and TLR4 activation was assessed by subsequent stimulation with TLR agonists Staphylococcus aureus lipoteichoic acid (SLTA; TLR2 ligand) and Escherichia coli lipopolysaccharide (LPS; TLR4 ligand). Unchallenged HAEC failed to elicit monocyte chemoattractant protein 1 (MCP-1) in response to LPS or SLTA but did so when cultured with wild-type P. gingivalis. P. gingivalis-induced TLR2 and -4 expression on HAEC functionally reacted to SLTA and E. coli LPS as measured by a further increase in MCP-1 production. Furthermore, MCP-1 expression elicited by E. coli LPS was inhibitable with TLR4-specific antibody and polymyxin B. These results indicate that invasive P. gingivalis stimulates TLR expression on the surface of endothelium and these primed cells respond to defined TLR-specific ligands.

Identification of periodontal pathogens in atherosclerotic vessels

BACKGROUND

Epidemiological studies have shown that periodontitis may be associated with presence of atherosclerosis. DNA from periodontal pathogens has been detected in atherosclerotic lesions, but viable oral bacteria have not yet been isolated from atherosclerotic plaques. The purpose of the present study was to determine if viable oral bacteria could be isolated from atherosclerotic lesions and if DNA from periodontal pathogens could be detected by use of polymerase chain reaction (PCR) techniques.

METHODS

Seventy-nine specimens of atherosclerotic plaque removed from carotid or femoral arteries during surgery were immediately transferred to reduced transport fluid and brought to the laboratory. The calcified tissue was meticulously cut into fine pieces and used for cultivation of Porphyromonas gingivalis, Prevotella intermedia, P. nigrescens, Campylobacter rectus, Actinobacillus actinomycetemcomitans, Tannerella forsythensis, and oral streptococci. The material from 24 of the specimens was homogenized, DNA was extracted, and PCR amplification of 16S rDNA with universal and specific primers was carried out. Finally, the PCR products were sequenced.

RESULTS

None of the samples yielded growth of the oral bacteria under investigation. In all the 24 specimens bacterial DNA was detected and likewise DNA of P. intermedia was found in the samples. P. nigrescens and P. gingivalis were found sporadically.

CONCLUSIONS

Viable oral bacteria could not be isolated from the atheromas, but the data confirm that DNA of periodontal pathogens can be detected in atherosclerotic plaques. However, the finding that DNA from P. intermedia constantly occured in the examined samples was new. Further studies may focus on the simultaneous occurrence of identical clones of this species in subgingival plaque and atherosclerotic plaques.

Dental Caries, Periodontal Disease, and Cardiac Arrhythmias in Community-Dwelling Older Persons Aged 80 and Older: Is There a Link?

OBJECTIVES

To examine whether caries or periodontitis is associated with cardiac arrhythmias in community-dwelling people aged 80 and older.

SETTING

Urban, community-based population in Stockholm, Sweden.

DESIGN

Cross-sectional.

PARTICIPANTS

Eligible persons were identified through the Kungsholmen Project, which is an ongoing, longitudinal, population-based study of the oldest old. The present study included 125 dentate individuals.

MEASUREMENTS

Data from interviews, a medical examination, and an oral examination. The assessment of cardiac arrhythmia was based on a clinical examination by a physician or the Stockholm Inpatient Register. Active root caries, active coronal caries, and periodontitis were assessed using previously defined National Institute of Dental and Craniofacial Research diagnostic criteria.

RESULTS

The primary finding of the multivariate logistic regression analysis was that persons with three or more active root caries lesions had more than twice the odds of cardiac arrhythmias than persons without active root caries. The results did not notably change after adjusting for age, medications that reduce saliva, and number of teeth. Persons with one to two active coronal caries lesions had 2.8 times higher odds (95% confidence interval=1.1-7.0) of arrhythmia than persons without active coronal caries, but there was no greater risk for persons with three or more coronal caries lesions. There was no association between periodontal disease and arrhythmia.

CONCLUSION

The findings indicate that there may be a link between active root caries and cardiac arrhythmias in the oldest old. Nevertheless, although a biological pathway is not obvious, it is plausible that both are simply markers of declining general health. The results suggest the need for further study of these relationships.

Hydroxyl-platelet-activating factor exists in blood of healthy volunteers and periodontal patients

Periodontal diseases are localized chronic inflammatory conditions of the gingival and underlying bone and connective tissue. Platelet-activating factor (PAF), a potent inflammatory phospholipid mediator that has been previously detected in elevated levels in inflamed gingival tissues, in gingival crevicular fluid and in saliva, is implicated in periodontal disease. Our results from previous studies showed that the biologically active phospholipid detected in gingival crevicular fluid is a hydroxyl-PAF analogue. In this study, hydroxyl-PAF analogue was detected for the first time in human blood derived from patients with chronic periodontitis as well as from periodontally healthy volunteers. The hydroxyl-PAF analogue was purified by high-performance liquid chromatography, detected by biological assays and identified by electrospray analysis. In addition, the quantitative determination of PAF and hydroxyl-PAF analogue (expressed as PAF-like activity) showed a statistically significant increase in the ratio of hydroxyl-PAF analogue levels to PAF levels in periodontal patients, suggesting that this bioactive lipid may play a role in oral inflammation.

Oral health indicators poorly predict coronary heart disease deaths

Several earlier studies have suggested that development of coronary heart disease (CHD) is causally related to oral infections. The aim of this study was to investigate the association between oral health indicators and CHD deaths. Out of a nationally representative sample, 6527 men and women aged 30-69 years participated in the health examination with a dental check. Detailed oral health data included caries, periodontal and dental plaque status, presence of remaining teeth, and various types of dentures. Over a mean 12-year follow-up, persons dying of CHD were older and more often smoked, had hypertension, hypercholesterolemia, diabetes, and only a basic education compared with other persons. In univariate analyses, several oral health indicators were associated with CHD deaths. Adjustment for the established CHD risk factors reduced all these associations to statistical non-significance. The associations between oral health indicators and CHD are mostly explained by confounding factors, particularly those relating to health behavior.

Ecology of oral health: a complexity perspective

Health and disease are determined by many interwoven factors. Complexity theory may facilitate an understanding of oral health and disease by studying their complex interplay, and not focusing only on the importance of each individual factor involved. This introduces a theoretical basis for a dynamic, holistic approach to oral health with possible far-reaching consequences for dental education and diagnosis, prevention and treatment of oral diseases.

Oral health and health behavior in patients referred for open-heart surgery

OBJECTIVE

Little is known about the dental health and health behavior of patients referred for open-heart surgery because of severe heart disease. Yet, coronary atherosclerosis has been suggested to be an inflammatory disease in which chronic dental infections may trigger pathogenic mechanisms in the walls of arteries. In epidemiological studies periodontal disease in particular has been linked with coronary heart disease (CHD).

STUDY DESIGN

We set out to investigate by means of clinical examination, x-ray, and questionnaire the oral health status, health-related behavior, and conceptions of 256 CHD patients referred for open-heart surgery in the Kuopio University Hospital. The patients' heart disease was New York Heart Association grades II-IV. For comparison, 250 age- and sex-matched non-CHD patients were also studied. Differences between groups were analyzed conventionally and with the Total Dental Index (TDI), which uses linear modeling and logistic regression analyses to summarize periodontal factors and other signs of oral infections. We expected to find neglected dental care and worse oral health situation among the CHD patients.

RESULTS

Edentulousness was seen in 35% of the CHD group and in 15% of the non-CHD group (P < .001). The CHD group had significantly lower number of teeth (8.8 +/- 9.1) than the non-CHD group (17 +/- 10.5; P < .001). No dental appointment in the past 10 years was reported in 66% of the CHD patients and 35% of the non-CHD patients. Forty-nine percent of the CHD group and 69% of the non-CHD group had had a dental visit within the past 2 years (P < .001). Daily tooth brushing was reported by 46% of the CHD group and 56% of the non-CHD group (P < .05). Only 2% of the CHD group and 8% of the non-CHD group flossed daily (P < .001). TDI scores were significantly higher in the edentulous than in the dentate study groups (P < .001), but no difference was observed between CHD and non-CHD patients of the same dentate or edentulous status. Mean TDI score was 3.2 +/- 0.8 in edentulous CHD patients and 3.1 +/- 0.4 in edentulous non-CHD patients; the scores in the dentate patients were 2.5 +/- 0.9 in the CHD group and 2.4 +/- 2.0 in the non-CHD group. The TDI score appeared almost significant a predictor of CHD when used as a dependent variable in logistic regression analysis (P = .08).

CONCLUSION

Worse oral health status and less satisfactory oral health behavior were observed in the CHD patients than among the cardiologically healthy.

Induction of monocyte chemoattractant protein-1 by Porphyromonas gingivalis in human endothelial cells

The association between periodontal and cardiovascular diseases could be mediated by direct interaction of periodontal pathogens with cardiac tissue. In order to explore this possibility, the effect of the periodontal pathogen Porphyromonas gingivalis on monocyte chemoattractant protein-1 (MCP-1) production by endothelial cells was investigated. When incubated with live P. gingivalis 381, MCP-1 production by human umbilical vein endothelial cells (HUVEC) was potently increased. Compared to the type strain 381, non-adhesive/invasive strains (W50 and DPG3) did not increase MCP-1 production, which was also demonstrated at the mRNA level. Killed P. gingivalis 381 was much less effective than live bacteria for MCP-1 induction. Treatment of HUVEC with cytochalasin D, an inhibitor of endocytosis, prevented MCP-1 mRNA up-regulation by P. gingivalis 381, suggesting that internalization of P. gingivalis is necessary for MCP-1 induction. In conclusion, the secretion of high levels of MCP-1 resulting from interactions of P. gingivalis with endothelial cells could enhance atherosclerosis progression by contributing to the recruitment of monocytes.