Oral infection with a periodontal pathogen accelerates early atherosclerosis in apolipoprotein E-null mice

The Dynamics of Oxidized LDL during Atherogenesis

Accumulating evidence indicates that oxidized low-density lipoprotein (OxLDL) is a useful marker for cardiovascular disease. The uptake of OxLDL by scavenger receptors leads to the accumulation of cholesterol within the foam cells of atherosclerotic lesions. OxLDL has many stimulatory effects on vascular cells, and the presence of OxLDL in circulating blood has been established. According to the classical hypothesis, OxLDL accumulates in the atherosclerotic lesions over a long duration, leading to advanced lesions. However, recent studies on time-course changes of OxLDL in vivo raised a possibility that OxLDL can be transferred between the lesions and the circulation. In this paper, the in vivo dynamics of OxLDL are discussed.

Porphyromonas gingivalis lipopolysaccharide alters atherosclerotic-related gene expression in oxidized low-density-lipoprotein-induced macrophages and foam cells

BACKGROUND AND OBJECTIVE

The molecular mechanism linking atherosclerosis formation and periodontal pathogens is not clear, although a positive correlation between periodontal infections and cardiovascular diseases has been reported. The aim of this study was to determine whether stimulation with Porphyromonas gingivalis lipopolysaccharide (LPS) affected the expression of atherosclerosis-related genes, during and after the formation of foam cells.

MATERIAL AND METHODS

Macrophages from human THP-1 monocytes were treated with oxidized low-density lipoprotein (oxLDL) to induce the formation of foam cells. P. gingivalis LPS was added to cultures of either oxLDL-induced macrophages or foam cells. The expression of atherosclerosis-related genes was assayed by quantitative real-time PCR, and the production of granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein-1, interleukin (IL)-1β, IL-10 and IL-12 proteins was determined using ELISA. Nuclear translocation of nuclear factor-kappaB (NF-κB) P(65) was detected by immunocytochemistry, and western blotting was used to evaluate inhibitory kappa B-α (IκΒ-α) degradation to confirm activation of the NF-κB pathway.

RESULTS

P. gingivalis LPS stimulated atherosclerosis-related gene expression in foam cells and increased the oxLDL-induced expression of chemokines, adhesion molecules, growth factors, apoptotic genes and nuclear receptors in macrophages. Transcription of the proinflammatory cytokines IL1β and IL12 was elevated in response to LPS in both macrophages and foam cells, whereas transcription of the anti-inflammatory cytokine, IL10, was not affected. Increased activation of the NF-κB pathway was also observed in macrophages costimulated with LPS + oxLDL.

CONCLUSION

P. gingivalis LPS appears to be an important factor in the development of atherosclerosis by stimulation of atherosclerosis-related gene expression in both macrophages and foam cells via activation of the NF-κB pathway.

The effect of proatherogenic microbes on macrophage cholesterol homeostasis in apoE-deficient mice

BACKGROUND

Pathogens such as Aggregatibacter actinomycetemcomitans (Aa) and Chlamydia pneumoniae (Cpn) associate with an increased risk for cardiovascular diseases by inducing inflammation. We hypothesized that the pathogens affect the vascular wall by disturbing cholesterol homeostasis and endothelial function.

METHODS

Aa- and Cpn-infections were induced in apoE-deficient mice by intravenous and intranasal applications, respectively. Cholesterol efflux from mouse peritoneal macrophages to apo(lipoprotein)A-I was assessed. The efflux capacity of mouse sera as acceptors of cholesterol from RAW264.7-macrophages was determined. Additionally, endothelial function was studied by following the relaxation capacity of rat mesenteric arteries after incubation in the conditioned culture media of the peritoneal macrophages isolated from the mice.

RESULTS

Infection increased serum phospholipid transfer protein (PLTP) and lipopolysaccharide (LPS) activity, as well as serum amyloid A (SAA) and TNF-α concentrations. Peritoneal macrophages of mice with Aa-infection showed increased cholesterol uptake and reduced cholesterol efflux. Sera of Cpn and Cpn + Aa-infected mice had reduced cholesterol efflux capacity from RAW264.7-macrophages. Conditioned macrophage medium from mice with chronic C. pneumoniae infection induced endothelial dysfunction. Additionally, concentrations of serum adhesion molecules, intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) in Cpn-groups and E-selectin in Cpn + Aa-group, were elevated. The serum markers of endothelial function correlated positively with SAA.

CONCLUSIONS

Aa- and Cpn-infections may generate proatherogenic changes in the vascular wall by affecting the macrophage cholesterol homeostasis and endothelial function.

Diet, commensals and the intestine as sources of pathogen-associated molecular patterns in atherosclerosis, type 2 diabetes and non-alcoholic fatty liver disease

Stimulation of the innate immune receptors Toll-like receptor (TLR)-2 and TLR4 has been shown to promote the development of a variety of diseases involving dysregulated metabolism, including atherosclerosis, type 2 diabetes and non-alcoholic fatty liver disease. However, the origin and nature of the agents responsible for stimulating TLR2 or TLR4 signalling in these conditions remain to be clearly identified. This review summarises the evidence supporting the proposal that 'pathogen-associated molecular patterns' (PAMPs) derived from dietary and commensal sources may contribute to the chronic inflammatory processes that underpin the development of these diseases via stimulation of TLR2 and TLR4. In particular, insights gained from recent studies employing TLR-transfectant based bioassays to quantify the abundance of PAMPs in foodstuffs and specific commensal compartments are discussed. Finally, the major mechanisms by which TLR-stimulants may gain access to the circulation to promote systemic low-grade inflammation are considered.

The periodontal anaerobe Porphyromonas gingivalis induced platelet activation and increased aggregation in whole blood by rat model

INTRODUCTION

More and more evidence show that periodontal anaerobes contribute to pathogenesis of peripheral artery diseases. As a typical oral anaerobe that results in periodontitis, P.gingivalis aggregates platelets in PRP in vitro and participated in artery thrombosis. However, in vivo effect on platelet activation and aggregation remains unclear. This study aimed to clarify its role on platelets activation on more physiological environment, that is, on whole blood and systemic circulation.

MATERIALS AND METHODS

To fully estimate platelet activation, CD62P(P-selectin) expression on platelet surface and fibrinogen binding of platelet via conjugated glycoprotein GPIIb/IIIa in whole blood were assayed by flow cytometry, and platelet aggregation was measured on an impedance aggregometor. As primary study, platelet reactivity was assessed after in vitro rat whole blood incubation with P.gingivalis strain 381 in tubes, followed or not followed by ADP and arachidonic acid stimulation. In addition, PBS solution of P.gingivalis was infused into rat to produce transient bacteremia model for 5 minutes and blood samples were subjected to analysis for platelet activation in vivo.

RESULTS

P.gingivalis could not induce rat platelet aggregation in whole blood in vitro, but increased aggregation when irritated by collagen stimulation. Flow cytometric study showed that incubation with P.gingivalis increased CD62P expression and fibrinogen binding of platelet. Moreover, further stress by 10 μmol/L ADP and 260 mmlol/L arachidonic acid yielded additional expression. As in vivo study, after P.gingivalis solution challenged, rat platelet aggregability was enhanced, and CD62P positive percentage of platelets and further reactivity to ADP stimulation improved.

CONCLUSION

In whole blood and in systemic circulation, P.gingivalis could induce rat platelet activation and increase aggregability transiently. The results helped to understand the mechanism underlining which P.gingivalis promoted arteriosclerosis and thrombo-embolic disorders. Further study about chronic infection with P.gingivalis on platelet activity is expected.

Alterations of Serum Lipid and Inflammatory Cytokine Profiles in Patients with Coronary Heart Disease and Chronic Periodontitis: A Pilot Study

Serum lipid and inflammatory cytokine profiles were assessed in 124 in-patients with coronary heart disease (CHD) (CHD group) and 43 inpatients with no evidence of CHD (control group). In all patients, research questionnaires and examinations of periodontal health were conducted and venous blood samples were analysed. Both groups were divided into two subgroups according to the presence or absence of chronic periodontitis in individual patients. The prevalence of chronic periodontitis was higher in patients from the CHD group than in the control group. Levels of total cholesterol, triglycerides, low-density lipoprotein, oxidized low-density lipoprotein, high-sensitivity C-reactive protein, interleukin-6 and tumour necrosis factor-a were significantly higher in CHD patients with chronic periodontitis than in those without periodontitis. In conclusion, chronic periodontitis may be associated with CHD.

Molecular survey of atheromatous plaques for the presence of DNA from periodontal bacterial pathogens, archaea and fungi

BACKGROUND AND OBJECTIVE

Chronic infections, such as periodontitis, have been associated with the development and progression of atherosclerosis. The mechanisms through which this occurs have yet to be elucidated. This study was carried out to detect periodontopathic bacteria as well as archaea and fungi in atheromatous plaques and search for factors associated with their occurrence in atheromas.

MATERIAL AND METHODS

  A cross-sectional study was carried out including 30 patients diagnosed with atherosclerosis in the carotid, coronary or femoral arteries. Plaques were collected during surgery and analysed using PCR to detect Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola and members of the Synergistetes group. Samples were also surveyed with universal primers for bacterial, archaeal and fungal DNA. Patients responded to a questionnaire to determine factors associated with PCR results.

RESULTS

All dentate individuals (66.7%) had periodontal disease, 95% of which was severe and 65% extensive. None of the targeted periodontopathic bacteria was found in the atheromas. No sample yielded positive results for fungal and archaeal DNA. Four samples (13%) were positive for the presence of bacterial DNA. Of these, three participants were dentate (two with severely chronic generalized periodontitis and one with severely chronic localized periodontitis).

CONCLUSION

This study did not confirm previous findings of periodontal pathogens in atheromas, making it impossible to establish factors associated with their presence in plaques. Presence of bacterial DNA in some samples indicates that periodontal or nonoral bacterial species other than the ones targeted in this study may be involved with some cases of atherosclerosis.

Polymicrobial infection with periodontal pathogens specifically enhances microRNA miR-146a in ApoE-/- mice during experimental periodontal disease

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia are periodontal pathogens associated with the etiology of adult periodontitis as polymicrobial infections. Recent studies demonstrated that oral infection with P. gingivalis induces both periodontal disease and atherosclerosis in hyperlipidemic and proatherogenic ApoE(-/-) mice. In this study, we explored the expression of microRNAs (miRNAs) in maxillas (periodontium) and spleens isolated from ApoE(-/-) mice infected with P. gingivalis, T. denticola, and T. forsythia as a polymicrobial infection. miRNA expression levels, including miRNA miR-146a, and associated mRNA expression levels of the inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) were measured in the maxillas and spleens from mice infected with periodontal pathogens and compared to those in the maxillas and spleens from sham-infected controls. Furthermore, in response to these periodontal pathogens (as mono- and polymicrobial heat-killed and live bacteria), human THP-1 monocytes demonstrated similar miRNA expression patterns, including that of miR-146a, in vitro. Strikingly, miR-146a had a negative correlation with TNF-α secretion in vitro, reducing levels of the adaptor kinases IL-1 receptor-associated kinase 1 (IRAK-1) and TNF receptor-associated factor 6 (TRAF6). Thus, our studies revealed a persistent association of miR-146a expression with these periodontal pathogens, suggesting that miR-146a may directly or indirectly modulate or alter the chronic periodontal pathology induced by these microorganisms.

Why should a doctor be interested in oral disease?

Oral health has been implicated in systemic disease throughout the ages; however, the understanding of the relationship between oral disease and systemic diseases such as cardiovascular disease and Type 2 diabetes mellitus is still emerging today. Chronic periodontal disease is widespread in the general population and a significant proportion of adults suffer from the most severe form of the disease. Dental plaque biofilm is necessary for the development of chronic periodontal disease with genetic and environmental factors contributing towards the pathogenesis. The putative biological mechanisms of the association between oral disease and atherogenesis are discussed, although there is insufficient evidence to establish causality at this time. Regardless of a direct causal relationship between oral disease and cardiovascular disease, treatment of oral disease leads to both a reduction in the systemic inflammatory burden as reflected in inflammatory markers and an improvement in endothelial function and hence improved overall health outcomes. A brief overview of periodontal disease including etiology, pathogenesis, screening and therapeutic implications is presented.

Relationship between tooth loss and carotid intima-media thickness in Korean adults

PURPOSE

The aim of this study was to examine the relationship between tooth loss and sub-clinical atherosclerosis in Korean adults.

MATERIALS AND METHODS

The subjects were part of a cohort study conducted in Ansan city by the Korea University medical school as part of the Korean Genome project. 749 subjects over than 40 years old were evaluated. After taking panoramic radiography, the amount of tooth loss was calculated. The intima-media thickness (IMT) was assessed by using ultrasonography at the common carotid artery. Traditional cardiovascular risk factors for atherosclerosis were also evaluated. The relationship between tooth loss and the IMT was evaluated using ANOVA with Scheffe's multiple comparison method in univariate analysis. Multiple regression analysis was also performed to determine the significance between the IMT and tooth loss.

RESULTS

With age, tooth loss increased, but there was no significant increase in other traditional cardiovascular risk factors. Univariate analysis revealed the IMT to be positively related with the amount of tooth loss. Regression analysis of the IMT in the anterior and posterior tooth loss revealed that only the posterior tooth loss was significantly related with the IMT at all sites of the common carotid artery (right far wall, P = .015; left far wall, P = .008; right near wall, P < .001; left near wall, P = .001).

CONCLUSION

This study verified the positive relationship between the increased tooth loss at the posterior area and the accumulation of atheroma in arteries.

Virulence of major periodontal pathogens and lack of humoral immune protection in a rat model of periodontal disease

OBJECTIVE

This study was designed to test the hypothesis that periodontal pathogens Tannerella forsythia and Porphyromonas gingivalis are synergistic in terms of virulence potential using a model of mixed-microbial infection in rats.

MATERIALS AND METHODS

Three groups of rats were infected orally with either T. forsythia or P. gingivalis in mono-bacterial infections or as mixed-microbial infections for 12 weeks and a sham-infected group were used as a control. This study examined bacterial infection, inflammation, immunity, and alveolar bone loss changes with disease progression.

RESULTS

Tannerella forsythia and P. gingivalis genomic DNA was detected in microbial samples from infected rats by PCR indicating their colonization in the rat oral cavity. Primary infection induced significantly high IgG, IgG2b, IgG1, and IgG2a antibody levels indicating activation of mixed Th1 and Th2 immune responses. Rats infected with the mixed-microbial consortium exhibited significantly increased palatal horizontal and interproximal alveolar bone loss. Histological examinations indicated significant hyperplasia of the gingival epithelium with moderate inflammatory infiltration and apical migration of junctional epithelium. The results observed differ compared to uninfected controls.

CONCLUSION

Our results indicated that T. forsythia and P. gingivalis exhibit virulence, but not virulence synergy, resulting in the immuno-inflammatory responses and lack of humoral immune protection during periodontitis in rats.

Porphyromonas gingivalis accelerates inflammatory atherosclerosis in the innominate artery of ApoE deficient mice

OBJECTIVE

Studies in humans support a role for the oral pathogen Porphyromonas gingivalis in the development of inflammatory atherosclerosis. The goal of this study was to determine if P. gingivalis infection accelerates inflammation and atherosclerosis in the innominate artery of mice, an artery which has been reported to exhibit many features of human atherosclerotic disease, including plaque rupture.

METHODS AND RESULTS

Apolipoprotein E-deficient (ApoE-/-) mice were orally infected with P. gingivalis, and magnetic resonance imaging (MRI) was used to monitor the progression of atherosclerosis in live mice. P. gingivalis infected mice exhibited a statistically significant increase in atherosclerotic plaque in the innominate artery as compared to uninfected mice. Polarized light microscopy and immunohistochemistry revealed that the innominate arteries of infected mice had increased lipids, macrophages and T cells as compared to uninfected mice. Increases in plaque, total cholesterol esters and cholesterol monohydrate crystals, macrophages, and T cells were prevented by immunization with heat-killed P. gingivalis prior to pathogen exposure.

CONCLUSIONS

These are the first studies to demonstrate progression of inflammatory plaque accumulation in the innominate arteries by in vivo MRI analysis following pathogen exposure, and to document protection from plaque progression in the innominate artery via immunization.

Porphyromonas gingivalis accelerates inflammatory atherosclerosis in the innominate artery of ApoE deficient mice

OBJECTIVE

Studies in humans support a role for the oral pathogen Porphyromonas gingivalis in the development of inflammatory atherosclerosis. The goal of this study was to determine if P. gingivalis infection accelerates inflammation and atherosclerosis in the innominate artery of mice, an artery which has been reported to exhibit many features of human atherosclerotic disease, including plaque rupture.

METHODS AND RESULTS

Apolipoprotein E-deficient (ApoE-/-) mice were orally infected with P. gingivalis, and magnetic resonance imaging (MRI) was used to monitor the progression of atherosclerosis in live mice. P. gingivalis infected mice exhibited a statistically significant increase in atherosclerotic plaque in the innominate artery as compared to uninfected mice. Polarized light microscopy and immunohistochemistry revealed that the innominate arteries of infected mice had increased lipids, macrophages and T cells as compared to uninfected mice. Increases in plaque, total cholesterol esters and cholesterol monohydrate crystals, macrophages, and T cells were prevented by immunization with heat-killed P. gingivalis prior to pathogen exposure.

CONCLUSIONS

These are the first studies to demonstrate progression of inflammatory plaque accumulation in the innominate arteries by in vivo MRI analysis following pathogen exposure, and to document protection from plaque progression in the innominate artery via immunization.

Porphyromonas gingivalis-dendritic cell interactions: consequences for coronary artery disease

An estimated 80 million US adults have one or more types of cardiovascular diseases. Atherosclerosis is the single most important contributor to cardiovascular diseases; however, only 50% of atherosclerosis patients have currently identified risk factors. Chronic periodontitis, a common inflammatory disease, is linked to an increased cardiovascular risk. Dendritic cells (DCs) are potent antigen presenting cells that infiltrate arterial walls and may destabilize atherosclerotic plaques in cardiovascular disease. While the source of these DCs in atherosclerotic plaques is presently unclear, we propose that dermal DCs from peripheral inflamed sites such as CP tissues are a potential source. This review will examine the role of the opportunistic oral pathogen Porphyromonas gingivalis in invading DCs and stimulating their mobilization and misdirection through the bloodstream. Based on our published observations, combined with some new data, as well as a focused review of the literature we will propose a model for how P. gingivalis may exploit DCs to gain access to systemic circulation and contribute to coronary artery disease. Our published evidence supports a significant role for P. gingivalis in subverting normal DC function, promoting a semimature, highly migratory, and immunosuppressive DC phenotype that contributes to the inflammatory development of atherosclerosis and, eventually, plaque rupture.

Cardiovascular disease and the role of oral bacteria

In terms of the pathogenesis of cardiovascular disease (CVD) the focus has traditionally been on dyslipidemia. Over the decades our understanding of the pathogenesis of CVD has increased, and infections, including those caused by oral bacteria, are more likely involved in CVD progression than previously thought. While many studies have now shown an association between periodontal disease and CVD, the mechanisms underpinning this relationship remain unclear. This review gives a brief overview of the host-bacterial interactions in periodontal disease and virulence factors of oral bacteria before discussing the proposed mechanisms by which oral bacterial may facilitate the progression of CVD.

Nasal immunization with a fusion protein consisting of the hemagglutinin A antigenic region and the maltose-binding protein elicits CD11c(+) CD8(+) dendritic cells for induced long-term protective immunity

We assessed the efficacy of a fusion protein consisting of the 25-kDa antigenic region of Porphyromonas gingivalis hemagglutinin A and the Escherichia coli maltose-binding protein (25k-hagA-MBP) as a nasal vaccine for the prevention of oral infection with P. gingivalis. Nasal immunization with 25k-hagA-MBP induced high levels of 25k-hagA-specific serum IgG, serum IgA, and salivary IgA antibodies in a Toll-like receptor 4 (TLR4)-dependent manner. These antibody responses were maintained for at least 1 year after immunization. Analysis of cytokine responses showed that nasal administration of 25k-hagA-MBP induced antigen-specific CD4(+) T cells producing interleukin 4 (IL-4) and IL-5, but not gamma interferon (IFN-γ), in the spleen and cervical lymph nodes (CLNs). Furthermore, increased numbers of CD11c(+) CD8α(+), but not CD11c(+) CD11b(+) or CD11c(+) B220(+), dendritic cells with upregulated expression of CD80, CD86, CD40, and major histocompatibility complex class II (MHC II) molecules were noted in the spleen, CLNs, and nasopharynx-associated lymphoreticular tissues (NALT). Interestingly, when 25k-hagA-MBP or cholera toxin (CT) was given intranasally to enable examination of their presence in neuronal tissues, the amounts of 25k-hagA-MBP were significantly lower than those of CT. Importantly, mice given 25k-hagA-MBP nasally showed a significant reduction in alveolar bone loss caused by oral infection with P. gingivalis, even 1 year after the immunization. These results suggest that 25k-hagA-MBP administered nasally would be an effective and safe mucosal vaccine against P. gingivalis infection and may be an important tool for the prevention of chronic periodontitis in humans.

LPS from Porphyromonas gingivalis increases the sensitivity of contractile response mediated by endothelin-B (ET(B)) receptors in cultured endothelium-intact rat coronary arteries

The purpose of our study was to examine if lipopolysaccharide (LPS) from Porphyromonas gingivalis (P.g.) modifies the vasomotor responses to Endothelin-1 (ET-1) and Sarafotoxin 6c (S6c) in rat coronary arteries. The arteries were studied directly or following organ culture for 24 h in absence and presence of 2.5EU/ml LPS. The contractile responses of coronary arteries were investigated by using the selective ETB receptor agonist S6c (1 pM-0.3 μM) and ET-1 (1 pM-0.3 μM). The functional studies demonstrated an augmented contractile response only to S6c in isolated rat coronary arteries after organ culture (with or without LPS). These contractile responses by S6c were blocked by the selective ETB receptor antagonist BQ788 in both vessel groups. The augmented contractile response to S6c was supported by immunohistochemistry, where a significant increase in fluorescence intensity for ETB receptors in smooth muscle cells was observed after organ culture. The presence of LPS in the culture medium significantly increased the sensitivity of endothelium-intact coronary artery to S6c as compared to endothelium-denuded segments. Our results showed a significant increase in both ETB receptor protein levels and S6c-induced maximal contraction in coronary arteries upon 24 h of organ culture, which was further sensitized by LPS.

Presence of periodontopathic bacteria in coronary arteries from patients with chronic periodontitis

In this study the presence of periodontopathic pathogens in atheromatous plaques removed from coronary arteries of patients with chronic periodontitis and periodontally healthy subjects by PCR was detected. Our results indicate a significant association between the presence of Porphyromonas gingivalis and atheromas, and the periodontal bacteria in oral biofilm may find a way to reach arteries.

Receptor for advanced glycation endproducts mediates pro-atherogenic responses to periodontal infection in vascular endothelial cells

OBJECTIVE

A link between periodontal infections and an increased risk for vascular disease has been demonstrated. Porphyromonas gingivalis, a major periodontal pathogen, localizes in human atherosclerotic plaques, accelerates atherosclerosis in animal models and modulates vascular cell function. The receptor for advanced glycation endproducts (RAGE) regulates vascular inflammation and atherogenesis. We hypothesized that RAGE is involved in P. gingivalis's contribution to pro-atherogenic responses in vascular endothelial cells.

METHODS AND RESULTS

Murine aortic endothelial cells (MAEC) were isolated from wild-type C57BL/6 or RAGE-/- mice and were infected with P. gingivalis strain 381. P. gingivalis 381 infection significantly enhanced expression of RAGE in wild-type MAEC. Levels of pro-atherogenic advanced glycation endproducts (AGEs) and monocyte chemoattractant protein 1 (MCP-1) were significantly increased in wild-type MAEC following P. gingivalis 381 infection, but were unaffected in MAEC from RAGE-/- mice or in MAEC infected with DPG3, a fimbriae-deficient mutant of P. gingivalis 381. Consistent with a role for oxidative stress and an AGE-dependent activation of RAGE in this setting, both antioxidant treatment and AGE blockade significantly suppressed RAGE gene expression and RAGE and MCP-1 protein levels in P. gingivalis 381-infected human aortic endothelial cells (HAEC).

CONCLUSION

The present findings implicate for the first time the AGE-RAGE axis in the amplification of pro-atherogenic responses triggered by P. gingivalis in vascular endothelial cells.

"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.

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.

Porphyromonas gingivalis and Treponema denticola Mixed Microbial Infection in a Rat Model of Periodontal Disease

Porphyromonas gingivalis and Treponema denticola are periodontal pathogens that express virulence factors associated with the pathogenesis of periodontitis. In this paper we tested the hypothesis that P. gingivalis and T. denticola are synergistic in terms of virulence; using a model of mixed microbial infection in rats. Groups of rats were orally infected with either P. gingivalis or T. denticola or mixed microbial infections for 7 and 12 weeks. P. gingivalis genomic DNA was detected more frequently by PCR than T. denticola. Both bacteria induced significantly high IgG, IgG2b, IgG1, IgG2a antibody levels indicating a stimulation of Th1 and Th2 immune response. Radiographic and morphometric measurements demonstrated that rats infected with the mixed infection exhibited significantly more alveolar bone loss than shaminfected control rats. Histology revealed apical migration of junctional epithelium, rete ridge elongation, and crestal alveolar bone resorption; resembling periodontal disease lesion. These results showed that P. gingivalis and T. denticola exhibit no synergistic virulence in a rat model of periodontal disease.

Roles of oral bacteria in cardiovascular diseases--from molecular mechanisms to clinical cases: Implication of periodontal diseases in development of systemic diseases

Periodontal diseases, some of the most common infectious diseases seen in humans, are characterized by gingival inflammation, as well as loss of connective tissue and bone from around the roots of the teeth, which leads to eventual tooth exfoliation. In the past decade, the association of periodontal diseases with the development of systemic diseases has received increasing attention. Although a number of studies have presented evidence of close relationships between periodontal and systemic diseases, the majority of findings are limited to epidemiological studies, while the etiological details remain unclear. Nevertheless, a variety of recent hypothesis driven investigations have compiled various results showing that periodontal infection and subsequent direct oral-hematogenous spread of bacteria are implicated in the development of various systemic diseases. Herein, we present current understanding in regard to the relationship between periodontal and systemic diseases, including cardiovascular diseases, preterm delivery of low birth weight, diabetes mellitus, respiratory diseases, and osteoporosis.

Pathogen-mediated inflammatory atherosclerosis is mediated in part via Toll-like receptor 2-induced inflammatory responses

Studies in humans have established that polymorphisms in genes encoding the innate immune Toll-like receptors (TLRs) are associated with inflammatory atherosclerosis. In hyperlipidemic mice, TLR2 and TLR4 have been reported to contribute to atherosclerosis progression. Human and mouse studies support a role for the oral pathogen Porphyromonas gingivalis in atherosclerosis, although the mechanisms by which this pathogen stimulates inflammatory atherosclerosis via innate immune system activation is not known. Using a genetically defined apolipoprotein E-deficient (ApoE(-/-)) mouse model we demonstrate that pathogen-mediated inflammatory atherosclerosis occurs via both TLR2-dependent and TLR2-independent mechanisms. P. gingivalis infection in mice possessing functional TLR2 induced the accumulation of macrophages as well as inflammatory mediators including CD40, IFN-gamma and the pro-inflammatory cytokines IL-1 beta, IL-6 and tumor necrosis factor-alpha in atherosclerotic lesions. The expression of these inflammatory mediators was reduced in atherosclerotic lesions from P. gingivalis-infected TLR2-deficient (TLR2(-/-)) mice. These studies provide a mechanistic link between an innate immune receptor and pathogen-accelerated atherosclerosis by a clinically and biologically relevant bacterial pathogen.

Mechanisms of oral bacteria-induced platelet activation

The oral cavity is inhabited by over 500 different bacterial species that normally exist in ecological balance both with each other and with the host. When this equilibrium is disturbed, an overgrowth of individual organisms can occur, which, in turn, can lead to the onset of pathological processes, notably dental caries and periodontitis. Generally, bacteraemias occur more frequently in individuals with periodontal disease, and these bacteraemias have been implicated in the development of a range of systemic diseases, including atherothrombotic disorders. The mechanism underlying this relationship remains to be precisely defined, although studies have shown a link between bacteria of oral origin and platelet activation. Several orally derived species of bacteria interact with platelets, including those of the Streptococcus ( Streptococcus sanguinis , Streptococcus mutans , Streptococcus agalactiae , Streptococcus pyogenes , Streptococcus gordonii , Streptococcus pneumoniae , Streptococcus mitis ) and Staphylococcus ( Staphylococcus epidermidis , Staphylococcus capitis ) genera, as well as Pseudomonas aeruginosa and Porphyromonas gingivalis . In addition, some members of both the Streptococcus and the Staphylococcus genera, as well as Porphyromonas gingivalis , can activate platelets in vitro. The current review describes the heterogeneous mechanisms of platelet activation employed by individual bacterial species. The pathological and clinical implications of platelet activation by orally derived bacteria are discussed.

Aggregatibacter actinomycetemcomitans accelerates atherosclerosis with an increase in atherogenic factors in spontaneously hyperlipidemic mice

Cariogenic and periodontal pathogens are thought to be etiological factors in the development of cardiovascular disease. We assessed the involvement of the periodontal pathogen Aggregatibacter actinomycetemcomitans and cariogenic pathogen Streptococcus mutans in the development of atherosclerosis in apolipoprotein E-deficient spontaneously hyperlipidemic (Apoe(shl)) mice. The mice were treated intravenously with A. actinomycetemcomitans HK1651, S. mutans GS-5, or phosphate-buffered saline three times a week for 3 weeks and killed at 15 weeks of age. The areas of the aortic sinus that were covered with atherosclerotic plaque were significantly larger in Apoe(shl) mice challenged with A. actinomycetemcomitans compared with S. mutans- or vehicle-challenged mice. Aggregatibacter actinomycetemcomitans challenge increased serum high-sensitive C-reactive protein and lipopolysaccharide levels. Bacterial DNA was detected in the blood, heart, and spleen, but not in the liver. Furthermore, serum interleukin-6 (IL-6), IL-8, tumor necrosis factor alpha, and MCP-1 levels and Toll-like receptor (TLR)2, TLR4, ICAM-1, E-selectin, P-selectin, LOX-1, HSP60, CCL19, CCL21, CCR7, and MCP-1 expressions in the aorta were significantly increased in mice challenged with A. actinomycetemcomitans. These results suggest that systemic infection with A. actinomycetemcomitans accelerates atherosclerosis in Apoe(shl) mice by exposing the whole microorganisms or their products, followed by initiating inflammation. Increases in proatherogenic factors may explain the aggravation of atherosclerosis by A. actinomycetemcomitans infection.

Modulation of allergic airway inflammation by the oral pathogen Porphyromonas gingivalis

Accumulating evidence suggests that bacteria associated with periodontal disease may exert systemic immunomodulatory effects. Although the improvement in oral hygiene practices in recent decades correlates with the increased incidence of asthma in developed nations, it is not known whether diseases of the respiratory system might be influenced by the presence of oral pathogens. The present study sought to determine whether subcutaneous infection with the anaerobic oral pathogen Porphyromonas gingivalis exerts a regulatory effect on allergic airway inflammation. BALB/c mice sensitized and subsequently challenged with ovalbumin exhibited airway hyperresponsiveness to methacholine aerosol and increased airway inflammatory cell influx and Th2 cytokine (interleukin-4 [IL-4], IL-5, and IL-13) content relative to those in nonallergic controls. Airway inflammatory cell and cytokine contents were significantly reduced by establishment of a subcutaneous infection with P. gingivalis prior to allergen sensitization, whereas serum levels of ovalbumin-specific IgE and airway responsiveness were not altered. Conversely, subcutaneous infection initiated after allergen sensitization did not alter inflammatory end points but did reduce airway responsiveness in spite of increased serum IgE levels. These data provide the first direct evidence of a regulatory effect of an oral pathogen on allergic airway inflammation and responsiveness. Furthermore, a temporal importance of the establishment of infection relative to allergen sensitization is demonstrated for allergic outcomes.

Aggregatibacter actinomycetemcomitans leukotoxin: from threat to therapy

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that colonizes the human oral cavity and is the causative agent for localized aggressive periodontitis (LAP), an aggressive form of periodontal disease that occurs in adolescents. A. actinomycetemcomitans secretes a protein toxin, leukotoxin (LtxA), which helps the bacterium evade the host immune response during infection. LtxA is a membrane-active toxin that specifically targets white blood cells (WBCs). In this review, we discuss recent developments in this field, including the identification and characterization of genes and proteins involved in secretion, regulation of LtxA, biosynthesis, newly described activities of LtxA, and how LtxA may be used as a therapy for the treatment of diseases.

Intranasal immunization with Porphyromonas gingivalis and atherosclerosis

Periodontal disease is a highly prevalent disorder affecting up to 90% of the global population. Recent epidemiological studies have shown that an association exists between periodontal disease and cardiovascular disease. Porphyromonas gingivalis, the causative agent of destructive chronic inflammation in the periodontium, can accelerate atheroma deposition in animal models. Emerging evidence suggests that vaccination against this pathogen's virulence factors may confer disease resistance. In this review, we focus on the role of inflammatory mechanisms in the formation and activation of atherosclerotic plaques accelerated by P. gingivalis in an apo E-deficient mouse model. Further, we examine whether a nasal vaccine-induced antigen-specific mucosal response can reduce P. gingivalis-accelerated atherosclerosis.

Relationship between gingival angiopoietin-1 concentrations and depth of the adjacent gingival sulcus

BACKGROUND

The purpose of this study was to assess concentrations of angiopoietin (Ang)-1 at various stages of gingival inflammation. Ang-1 is an anti-inflammatory mediator present in various inflammatory diseases. However, its presence during the pathogenesis of gingival inflammation has not been established in vivo.

METHODS

Gingiva was obtained from 110 human donors before extraction of the adjacent teeth. The tissue was grouped based on adjacent probing depth and bleeding on probing (BOP). Gingiva adjacent to a <or=3-mm sulcus without BOP was classified as "normal" (N); gingiva adjacent to a 3-mm sulcus with BOP was classified as "diseased, slight" (DS); gingiva adjacent to a 4- to 6-mm sulcus featuring BOP was classified as "diseased, moderate" (DM); and gingiva adjacent to >6-mm sulci was classified as "diseased, severe" (DSev). Tissues were solublized, and concentrations of interleukin (IL)-1beta and -6, tumor necrosis factor (TNF)-alpha, endothelin (ET)-1, Ang-1, vascular cell adhesion molecule (VCAM)-1, and vascular endothelial growth factor (VEGF) were assessed by enzyme-linked immunosorbent assay. Data were compared by factorial analysis of variance, the post hoc Tukey test, and the Pearson correlation test. Groups were defined as significantly different when P <0.05.

RESULTS

Gingival concentrations of IL-1beta and -6, TNF-alpha, VEGF, and ET-1 were significantly greater, and VCAM-1 and Ang-1 were significantly lower, in DSev and DM than in N and DS tissues (P <0.05). In addition, gingival concentrations of IL-6, VEGF, and ET-1 were significantly greater, and VCAM-1 and Ang-1 were significantly lower, in DSev than in DM tissues (P <0.05). There were significant positive correlations among sulcular depth, IL-1beta and -6, TNF-alpha, VEGF, and ET-1 and negative correlations among VCAM-1, Ang-1, sulcular depth, and the other biomarkers (P <0.001).

CONCLUSIONS

Depleted tissue concentrations of Ang-1 may allow gingival inflammation to become more severe because VEGF and ET-1 secretion become less inhibited. Thus, the tissues become edematous and more likely to develop BOP.

Association between periodontal diseases and systemic diseases

Current evidence suggests that periodontal disease may be associated with systemic diseases. This paper reviewed the published data about the relationship between periodontal disease and cardiovascular diseases, adverse pregnancy outcomes, diabetes and respiratory diseases, focusing on studies conducted in the Brazilian population. Only a few studies were found in the literature focusing on Brazilians (3 concerning cardiovascular disease, 7 about pregnancy outcomes, 9 about diabetes and one regarding pneumonia). Although the majority of them observed an association between periodontitis and systemic conditions, a causal relationship still needs to be demonstrated. Further studies, particularly interventional well-designed investigations, with larger sample sizes, need to be conducted in Brazilian populations.

Molecular analysis of aortic intimal hyperplasia caused by Porphyromonas gingivalis infection in mice with endothelial damage

BACKGROUND AND OBJECTIVE

Porphyromonas gingivalis infection is thought to be a significant etiological factor in the development of cardiovascular diseases. However, scant definitive evidence has been presented concerning the pathological molecular mechanisms of these disorders. In the present study, we performed a molecular analysis of the developmental mechanisms of aortic intimal hyperplasia induced by P. gingivalis.

MATERIAL AND METHODS

The effects of P. gingivalis-induced bacteremia on intimal hyperplasia were evaluated using a mouse model of aortic hyperplasia created by photochemical-induced endothelial cell injury. Alterations of gene expression profiles in injured blood vessels of the mice were extensively analyzed using DNA microarray assays to identify the key molecules involved in P. gingivalis-induced hyperplasia. In addition, human aneurismal specimens from patients with or without P. gingivalis infection were analyzed histochemically.

RESULTS

Intravenous administration of P. gingivalis dramatically induced intimal hyperplasia in the mouse model. Concomitantly, S100 calcium-binding protein A9 (S100A9) and embryonic isoform of myosin heavy chain (SMemb), a proliferative phenotypic marker of smooth muscle cells, were significantly overexpressed on the surfaces of smooth muscle cells present in the injured blood vessels. Similarly, increased expressions of S100A9 and SMemb proteins were observed in aneurismal specimens obtained from P. gingivalis-infected patients.

CONCLUSION

We found that bacteremia induced by P. gingivalis leads to intimal hyperplasia associated with overexpressions of S100A9 and SMemb. Our results strongly suggest that oral-hematogenous spreading of P. gingivalis is a causative event in the development of aortic hyperplasia in periodontitis patients.

Detection of oxidized low-density lipoproteins in gingival crevicular fluid from dental patients

BACKGROUND AND OBJECTIVE

Oxidative modification of low-density lipoprotein (LDL) occurs in various diseased tissues and sites of local inflammation. For example, an increased plasma oxidized low-density lipoprotein (OxLDL) level is a well-known risk marker for cardiovascular diseases. Gingival crevicular fluid, the exudate from gingival tissues into the sulci, can be easily collected in a non-invasive manner. However, the possible presence of OxLDL in gingival crevicular fluid has not been studied. In this study, we established a procedure to measure OxLDL in human gingival crevicular fluid.

MATERIAL AND METHODS

Human gingival crevicular fluid was sampled with paper points or paper strips. The gingival crevicular fluid samples from healthy gingival sulci (pocket depth < 4 mm, n = 14) were subjected to western blot and/or sandwich ELISA. The amounts of OxLDL and LDL were measured by sandwich ELISA using an anti-oxidized phosphatidylcholine monoclonal antibody and two anti-apolipoprotein B antibodies. Venous blood samples were analyzed biochemically.

RESULTS

We tested two methods of gingival crevicular fluid collection, namely paper points and paper strips. Gingival crevicular fluid could be collected very safely with paper points and they showed good recovery of LDL and OxLDL throughout the analysis. Apolipoprotein B, the major protein component in LDL, was detected in gingival crevicular fluid by western blot, and OxLDL was found to be present in gingival crevicular fluid by ELISA. The OxLDL/LDL ratio in gingival crevicular fluid was 17.0 times higher than that in plasma.

CONCLUSION

This is the first report to show the presence of apolipoprotein B and apolipoprotein B- oxidized phosphatidylcholine complex, which correspond to LDL and OxLDL, respectively, in gingival crevicular fluid.

Circulating matrix metalloproteinase-8 (MMP-8) and MMP-9 are increased in chronic periodontal disease and decrease after non-surgical periodontal therapy

BACKGROUND

Periodontal disease shares risk factors with cardiovascular diseases and other systemic inflammatory diseases. The present study was designed to assess the circulating matrix metalloproteinases (MMPs) from chronic periodontal disease patients and, subsequently, after periodontal therapy.

METHODS

We compared the plasma concentrations of MMP-2, MMP-3, MMP-8, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2, and total gelatinolytic activity in patients with periodontal disease (n=28) with those of control subjects (n=22) before and 3 months after non-surgical periodontal therapy.

RESULTS

Higher plasma MMP-3, MMP-8, and MMP-9 concentrations were found in periodontal disease patients compared with healthy controls (all P<0.05), whereas MMP-2, TIMP-1, and TIMP-2 levels were not different. Treatment decreased plasma MMP-8 and MMP-9 concentrations by 35% and 39%, respectively (both P<0.02), while no changes were found in controls. MMP-2, MMP-3, TIMP-1, and TIMP-2 remained unaltered in both groups. Plasma gelatinolytic activity was higher in periodontal disease patients compared with controls (P<0.001) and decreased after periodontal therapy (P<0.05).

CONCLUSIONS

This study showed increased circulating MMP-8 and MMP-9 levels and proteolytic activity in periodontal disease patients that decrease after periodontal therapy. The effects of periodontal therapy suggest that it may attenuate inflammatory chronic diseases.

Innate immune signals in atherosclerosis

Atherosclerosis is a chronic disease characterised by lipid retention and inflammation in the arterial intima. Innate immune mechanisms are central to atherogenesis, involving activation of pattern-recognition receptors (PRRs) and induction of inflammatory processes. In a complex tissue, such as the atherosclerotic lesion, innate signals can originate from several sources and promote atherogenesis through ligation of PRRs. The receptors recognise conserved molecular patterns on pathogens and endogenous products of tissue injury and inflammation. Activation of PRRs might affect several aspects of atherosclerosis by acting on lesion resident cells. Scavenger receptors mediate antigen uptake and clearance of lipoproteins, thereby promoting foam cell formation. Signalling receptors, such as Toll-like receptors (TLRs), lead to induction of pro-inflammatory cytokines and antigen-specific immune responses. In this review we describe the innate mechanisms present in the plaque. We focus on TLRs, their cross-talk with other PRRs, and how their signalling cascades influence inflammation within the atherosclerotic lesion.

The 5-lipoxygenase as a common pathway for pathological brain and vascular aging

Epidemiological studies indicate age as a strong risk factor for developing cardiovascular and neurodegenerative diseases. During the aging process, changes in the expression of particular genes can influence the susceptibility to these diseases. 5-Lipoxygenase (5-LO) by oxidizing fatty acids forms leukotrienes, potent mediators of oxidative and inflammatory reactions, two key pathogenic events in both clinical settings. This enzyme is widely distributed in the cardiovascular as well as in the central nervous system, where its expression levels increase with age, suggesting that it may be involved in their diseases of aging. The central theme of this article is that during aging, 5-LO acts as biologic link between different stressors and the development of cardiovascular and neurodegenerative diseases. We hypothesize that the age-dependent upregulation of 5-LO represents a "priming" factor in the vasculature as well as in the brain, where a subsequent exposure to triggering stimuli (i.e., infections) leads to an abnormal chronic inflammatory reaction, and ultimately results in increased organ vulnerability and functional deficits.

Periodontitis and risk for atherosclerosis: an update on intervention trials

AIMS

Periodontitis has been associated with an increased risk of cardiovascular events. The nature of the association is unclear because both periodontitis and cardiovascular disease (CVD) share a host of risk factors. Intervention trials are critical to explore the relationship. If the association were causal, successful periodontal therapy will lead to an attenuation of the effect - CVD.

MATERIAL AND METHODS

The paper reviewed the design and the results of intervention trials aimed at improving systemic inflammation, endothelial dysfunction, carotid atherosclerosis and cardiovascular events.

RESULTS

Early systematic reviews and a definitive controlled clinical trial indicate that intensive periodontal therapy results in a decrease in systemic inflammation and an improvement of endothelial dysfunction in systemically healthy subjects. A pilot trial has indicated the feasibility to assess the impact of periodontal therapy on carotid atherosclerosis in a primary cardiac prevention design.

CONCLUSIONS

Efforts to test causality in the relationship between periodontitis and CVD are ongoing. Evidence to date is consistent with the notion that severe generalized periodontitis causes systemic inflammation and endothelial dysfunction. Periodontitis has effects that go beyond the oral cavity and its treatment and prevention may contribute to the prevention of atherosclerosis.

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.

Lipopolysaccharide associates with pro-atherogenic lipoproteins in periodontitis patients

INTRODUCTION

Periodontitis patients are known to suffer from endotoxemia, which may be among the major risk factors for atherosclerosis. In health, lipopolysaccharide (LPS) is mainly carried with high density lipoprotein (HDL) particles. Shift of LPS toward lipoproteins with lower densities may result in less effective endotoxin scavenging. Our aim was to determine plasma LPS activity and lipoprotein-distribution before and after treatment in periodontitis patients.

PATIENTS AND METHODS

Very low and intermediate density (VLDL-IDL), low density (LDL), HDL 2, HDL3, and lipoprotein-deficient plasma (LPDP) were isolated by sequential ultracentrifugation. Patients included 34 subjects aged 53.5 +/- 8.3 years, before and 6 months after periodontal treatment.

RESULTS

The mean LPS distribution decreased among lipoprotein classes as follows: VLDL-IDL 41.3 +/- 12.1%, LPDP 25.0 +/- 7.0%, HDL3 13.1 +/- 5.2%, LDL 11.5 +/- 3.7%, and HDL2 9.2 +/- 2.8%. Plasma and VLDL-IDL-associated LPS correlated positively, and LDL- and HDL-associated LPS negatively with clinical periodontal parameters and plasma cytokine concentrations. Mean plasma LPS activity increased after periodontal treatment from 44.0 +/- 17.0 to 55.7 +/- 24.2 EU/ml (P = 0.006). No significant changes were found in LPS lipoprotein distribution and lipoprotein compositions after the treatment.

CONCLUSIONS

Endotoxemia increases with severity of periodontitis. In periodontitis, LPS associates preferentially with the pro-atherogenic VLDL-IDL fraction. Periodontal treatment has only minor effects on plasma LPS activity or distribution, which reflects persistence of the disease.