Detection and localization of periodontopathic bacteria in abdominal aortic aneurysms

Relationship between Gut, Blood, Aneurysm Wall and Thrombus Microbiome in Abdominal Aortic Aneurysm Patients

Previous research confirmed gut dysbiosis and translocation of selected intestinal bacteria into the vessel wall in abdominal aortic aneurysm patients. We studied the stool, blood, thrombus and aneurysm microbiomes of 21 abdominal aortic aneurysm patients using 16S rRNA sequencing. Our goals were to determine: 1. whether the microbiome characteristic of an aneurysm differs from that of a healthy vessel, 2. whether bacteria detectable in the aneurysm are translocated from the gut through the bloodstream, 3. whether the enzymatic activity of the aneurysm microbiome can contribute to the destruction of the vessel wall. The abundance of Acinetobacter, Burkholderia, Escherichia, and Sphingobium in the aneurysm samples was significantly higher than that in the microbiome of healthy vessels, but only a part of these bacteria can come from the intestine via the blood. Environmental bacteria due to the oral cavity or skin penetration route, such as Acinetobacter, Sphingobium, Enhydrobacter, and Aquabacterium, were present in the thrombus and aneurysm with a significantly higher abundance compared to the blood. Among the enzymes of the microbiome associated with the healthy vessel wall, Iron-chelate-transporting ATPase and Polar-amino-acid-transporting ATPase have protective effects. In addition, bacterial Peptidylprolyl isomerase activity found in the aneurysm has an aggravating effect on the formation of aneurysm.

Investigating the association between gut microbiome and aortic aneurysm diseases: a bidirectional two-sample Mendelian randomization analysis

Objective

This study aims to investigate the associations between specific bacterial taxa of the gut microbiome and the development of aortic aneurysm diseases, utilizing Mendelian Randomization (MR) to explore these associations and overcome the confounding factors commonly present in observational studies.

Methods

Employing the largest available gut microbiome and aortic aneurysm Genome-Wide Association Study databases, including MiBioGen, Dutch Microbiome Project, FinnGen, UK Biobank, and Michigan Genomics Initiative, this study performs two-sample bidirectional MR analyses. Instrumental variables, linked to microbiome taxa at significant levels, were selected for identifying relationships with abdominal aortic aneurysms (AAA), thoracic aortic aneurysms (TAA), and aortic dissection (AD). Methods like inverse variance weighted, MR-PRESSO, MR-Egger, weighted median, simple mode, and mode-based estimate were used for MR analysis. Heterogeneity was assessed with the Cochran Q test. MR-Egger regression and MR-PRESSO addressed potential unbalanced horizontal pleiotropy.

Results

The analysis did not find any evidence of statistically significant associations between the gut microbiome and aortic aneurysm diseases after adjusting for the false discovery rate (FDR). Specifically, while initial results suggested correlations between 19 taxa and AAA, 25 taxa and TAA, and 13 taxa with AD, these suggested associations did not hold statistical significance post-FDR correction. Therefore, the role of individual gut microbial taxa as independent factors in the development and progression of aortic aneurysm diseases remains inconclusive. This finding underscores the necessity for larger sample sizes and more comprehensive studies to further investigate these potential links.

Conclusion

The study emphasizes the complex relationship between the gut microbiome and aortic aneurysm diseases. Although no statistically significant associations were found after FDR correction, the findings provide valuable insights and highlight the importance of considering gut microbiota in aortic aneurysm diseases research. Understanding these interactions may eventually contribute to identifying new therapeutic and preventive strategies for aortic aneurysm diseases.

Altered salivary microbiota profile in patients with abdominal aortic aneurysm

Evidence suggests that the DNA of oral pathogens is detectable in the dilated aortic tissue of abdominal aortic aneurysm (AAA), one of the most fatal cardiovascular diseases. However, the association between oral microbial homeostasis and aneurysm formation remains largely unknown. In this study, a cohort of individuals, including 53 AAA patients and 30 control participants (CTL), was recruited for salivary microbiota investigation by 16S rRNA gene sequencing and bioinformatics analysis. Salivary microbial diversity was decreased in AAA compared with CTL, and the microbial structures were significantly separated between the two groups. Additionally, significant taxonomic and functional changes in the salivary microbiota of AAA participants were observed. The genera Streptococcus and Gemella were remarkably enriched, while Selenomonas, Leptotrichia, Lautropia and Corynebacterium were significantly depleted in AAA. Co-occurrence network analysis showed decreased potential interactions among the differentially abundant microbial genera in AAA. A machine-learning model predicted AAA using the combination of 5 genera and 14 differentially enriched functional pathways, which could distinguish AAA from CTL with an area under the receiver-operating curve of 90.3 %. Finally, 16 genera were found to be significantly positively correlated with the morphological parameters of AAA. Our study is the first to show that AAA patients exhibit oral microbial dysbiosis, which has high predictive power for AAA, and the over-representation of specific salivary bacteria may be associated with AAA disease progression. Further studies are needed to better understand the function of putative oral bacteria in the etiopathogenesis of AAA.

Importance

Host microbial dysbiosis has recently been linked to AAA as a possible etiology. To our knowledge, studies of the oral microbiota and aneurysms remain scarce, although previous studies have indicated that the DNA of some oral pathogens is detectable in aneurysms by PCR method. We take this field one step further by investigating the oral microbiota composition of AAA patients against control participants via high-throughput sequencing technologies and unveiling the potential microbial biomarker associated with AAA formation. Our study will provide new insights into AAA etiology, treatment and prevention from a microecological perspective and highlight the effects of oral microbiota on vascular health.

Torque Teno virus DNA is found in the intracranial aneurysm wall-Is there a causative role?

Objective

Torque Teno virus (TTV) is a recently discovered virus with high prevalence worldwide, that has been associated with vascular diseases. The aim of this study is to investigate the prevalence of TTV molecular DNA in the intracranial aneurysm (IA) artery walls.

Method

Samples of IA walls were collected after microsurgical clipping from 35 patients with IA (22 ruptured/13 unruptured cases). The samples were submitted to molecular DNA extraction using the EasyMag automatized extractor and performed with Qiagen DNA extraction Minikit 250. The samples underwent PCR examination with primers for β-globin as internal control using the Nanodrop ^® 2000 spectrophotometer. A quantitative (real-time) PCR with TTV-specific primers was performed. Clinical and radiological data of patients included was collected.

Results

TTV was detected in 15 (42.85%) cases, being 10 (45.4%) ruptured and 5 (38.4%) unruptured (p = 0.732) lesions. Multiple IAs accounted for 14 (40%) cases. Five cases (17.2%) had TTV+ and multiple aneurysms (p = 0.73). Association between presence of virus and aneurysm rupture was not statistically significant (p = 0.96).

Conclusion

This study demonstrated a relatively high prevalence of viral DNA in the walls of IAs. This is the first study to identify the presence of TTV DNA in IA's samples, which was found more often in ruptured lesions. This is an exploratory study, therefore, larger studies are required to clarify the relationships between inflammation, viral infection, IA formation and rupture.

Periodontal status and the incidence of selected bacterial pathogens in periodontal pockets and vascular walls in patients with atherosclerosis and abdominal aortic aneurysms

The aim of the study was to examine the periodontal status of patients with atherosclerosis and abdominal aortic aneurysms. The occurrence of 5 periodontopathogens was evaluated in periodontal pockets and atheromatous plaques together with specimens from pathologically changed vascular walls of aortic aneurysms. The study comprised 39 patients who qualified for vascular surgeries. Patients with periodontitis and concomitant atherosclerosis or aneurysms were enrolled in the study. Periodontal indices were evaluated, and subgingival plaque samples were examined together with atheromatous plaques or specimens from vascular walls to identify, by polymerase chain reaction (PCR), the following periodontopathogens: Porphyromonas gingivalis, Tanarella forsythia, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Treponema denticola. The majority of patients had chronic severe generalized periodontitis in stages III and IV. Laboratory investigations showed the occurrence of one or more of the five targeted periodontopathogens in 94.6% of the periodontal pockets examined. Of the examined periodontopathogens, only Porphyromonas gingivalis was confirmed in 1 atheromatous plaque sample collected from the wall of an aortic aneurysm. Therefore, the occurrence of this bacterium in these vessels was considered to be occasional in patients with chronic periodontitis.

Topical application of Porphyromonas gingivalis into the gingival pocket in mice leads to chronic‑active infection, periodontitis and systemic inflammation

Porphyromonas gingivalis (Pg), one of the 'red-complex' perio-pathogens known to play a critical role in the development of periodontitis, has been used in various animal models to mimic human bacteria-induced periodontitis. In order to achieve a more realistic animal model of human Pg infection, the present study investigated whether repeated small-volume topical applications of Pg directly into the gingival pocket can induce local infection, including periodontitis and systemic vascular inflammation in wild-type mice. Freshly cultured Pg was topically applied directly into the gingival pocket of the second molars for 5 weeks (3 times/week). After the final application, the mice were left in cages for 4 or 8 weeks and sacrificed. The status of Pg colony formation in the pocket, gingival inflammation, alveolar bone loss, the expression levels of pro-inflammatory cytokines in the serum and aorta, the presence of anti-Pg lipopolysaccharide (LPS) and gingipain (Kpg and RgpB) antibodies in the serum, as well as the accumulation of Pg LPS and gingipain aggregates in the gingiva and arterial wall were evaluated. The topical application of Pg into the gingival pocket induced the following local and systemic pathohistological changes in mice when examined at 4 or 8 weeks after the final topical Pg application: Pg colonization in the majority of gingival pockets; increased gingival pocket depths; gingival inflammation indicated by the increased expression of TNF-α, IL-6 and IL-1β; significant loss of alveolar bone at the sites of topical Pg application; and increased levels of pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-17, IL-13, KC and IFN-γ in the serum in comparison to those from mice receiving PBS. In addition, the Pg application/colonization model induced anti-Pg LPS and gingipain antibodies in serum, as well as the accumulation of Pg LPS and gingipain aggregates in the gingivae and arterial walls. To the best of our knowledge, this mouse model represents the first example of creating a more sustained local infection in the gingival tissues of wild-type mice and may prove to be useful for the investigation of the more natural and complete pathogenesis of the bacteria in the development of local oral and systemic diseases, such as atherosclerosis. It may also be useful for the determination of a treatment/prevention/efficacy model associated with Pg-induced colonization periodontitis in mice.

Pathological and immunological differences of arterial thrombi and wall caused by three different periodontal bacterial injections in rat models and proposals on the pathogeneses of vascular diseases

OBJECTIVES

Periodontal bacteria that have been studied show a strong connection to various vascular diseases. Among the many kinds of periodontal bacteria, Porphyromonas gingivalis (Pg) is well examined in the general aspects and in a rat model. However, whether other periodontal bacteria work or react differently is not studied well.

MATERIAL AND METHODS

We chose Aggregatibacter actinomycetemcomitans (Aa) and Prevotella intermedia (Pi) as different types of periodontal bacteria. Low-density and high-density bacterial solutions were injected in the small artery of rats' groins using our rat model. Eighteen limbs of 9 SD male rats (500-650 g) were used. After 7 days, 14-18 days, and 28 days, the rats were sacrificed. A pathological and an immuno-histochemical study was conducted and reported on the low-density group with 12 limbs because the Pi group lacked a high-density study. Immuno-histochemical staining of live Pg was performed on three limbs of three rats at 1 h, 3 h, and 1 week after injection.

RESULTS

The appearances from the acute, at 7 days, to chronic phases, at 28 days, were observed. The differences of the species were certainly observed in the internal elastic lamina (IEL), and immuno-histochemical reactions. The inflammatory reactions, such as cellular distribution or intra-thrombus materials, were similar in all. One week later, we could not see any living bacteria in the specimen or immunological observation.

CONCLUSIONS

The three species were essentially the same, except for Aa's stronger disruption of IEL, and more CD3 (Pan T cell) in Pi and more CD79a (Pan B cell) in Pg. We propose a new concept of a possible mechanism of vascular diseases, in which the work of LPS (lipopolysaccharides) and a toll-like receptor (TLR) is emphasized.

Dynamic analysis of Porphyromonas gingivalis invasion into blood capillaries during the infection process in host tissues using a vascularized three-dimensional human gingival model

Porphyromonas gingivalis, the pathogen of periodontal disease, is thought to be involved in various diseases throughout the body via gingival tissue blood capillaries. However, the dynamic analysis of the infection mechanism, particularly the deep invasion process of the gingival tissue, has not yet been elucidated because of the lack of both in vivo and in vitro models. In this study, we developed a vascularized three-dimensional (3D) gingival model with an epithelial barrier expressing cell-cell junctions using collagen microfibers (CMFs) to enable the dynamic analysis of the P. gingivalis invasion process. Lipid raft disruption experiments in the gingival epithelial cell layer demonstrated that P. gingivalis migrates into the deeper epithelium via the intercellular pathway rather than intracellular routes. P. gingivalis was shown to invade the 3D gingival model, being found inside blood capillaries during two days of culture. Notably, the number of bacteria had increased greatly at least two days later, whereas the mutant P. gingivalis lacking the cysteine proteases, gingipains, showed a significantly lower number of survivors. The secretion of interleukin-6 (IL-6) from the gingival tissue decreased during the two days of infection with the wild type P. gingivalis, but the opposite was found for the mutant suggesting that P. gingivalis infection disturbs IL-6 secretion at an early stage. By allowing the dynamic observation of the P. gingivalis invasion from the epithelial cell layer into the blood capillaries for the first time, this model will be a powerful tool for the development of novel therapeutics against periodontal infection related diseases.

Systemic immune response against the oral pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans is associated with the formation and rupture of intracranial aneurysms

BACKGROUND AND PURPOSE

Periodontal infections are associated with the formation and rupture of intracranial aneurysms (IAs). This study investigated the role of two key periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.

METHODS

Immunoglobulin A (IgA) and IgG antibodies against P. gingivalis and A. actinomycetemcomitans were measured with enzyme immune assay from the serum of 227 IA patients, of whom 64 also underwent clinical oral examination. As a control group, 1096 participants in a cross-sectional health survey, Health 2000, underwent serological studies and oral examination. Logistic regression was used for multivariate analysis. Immunohistochemistry was performed to demonstrate bacteria-derived epitopes in the IA wall.

RESULTS

Widespread gingivitis and severe periodontitis were more common in IA patients than in controls (2× and 1.5×, respectively). IgA antibodies against P. gingivalis and A. actinomycetemcomitans were 1.5× and 3-3.4× higher, respectively, in both unruptured and ruptured IA patients compared to controls (p ≤ 0.003). IgG antibodies against P. gingivalis were 1.8× lower in unruptured IA patients (p < 0.001). In multivariate analysis, high IgA, but low IgG, antibody levels against P. gingivalis (odds ratio [OR] = 1.4, 95% confidence interval [Cl] = 1.1-1.8 and OR = 1.5, 95% Cl = 1.1-1.9; OR = 0.6, 95% Cl = 0.4-0.7 and OR = 0.5, 95% Cl = 0.4-0.7) and against A. actinomycetemcomitans (OR = 2.3, 95% Cl = 1.7-3.1 and OR = 2.1, 95% Cl = 1.5-2.9; OR = 0.6, 95% Cl = 0.4-0.8 and OR = 0.6, 95% Cl = 0.5-0.9) were associated with the risk of IA formation and rupture. Immunohistochemistry showed P. gingivalis epitopes in the IA wall.

CONCLUSIONS

Exposure to the periodontal pathogens P. gingivalis and A. actinomycetemcomitans and dysfunctional acquired immune response against them may increase the risk of IA formation and IA rupture.

Pathophysiological Aspects of the Development of Abdominal Aortic Aneurysm with a Special Focus on Mitochondrial Dysfunction and Genetic Associations

Abdominal aortic aneurysm (AAA) is a complex degenerative vascular disease, with considerable morbidity and mortality rates among the elderly population. The mortality of AAA is related to aneurysm expansion (the enlargement of the aortic diameter up to 30 mm and above) and the subsequent rupture. The pathogenesis of AAA involves several biological processes, including aortic mural inflammation, oxidative stress, vascular smooth muscle cell apoptosis, elastin depletion, and degradation of the extracellular matrix. Mitochondrial dysfunction was also found to be associated with AAA formation. The evidence accumulated to date supports a close relationship between environmental and genetic factors in AAA initiation and progression. However, a comprehensive pathophysiological understanding of AAA formation remains incomplete. The open surgical repair of AAA is the only therapeutic option currently available, while a specific pharmacotherapy is still awaited. Therefore, there is a great need to clarify pathophysiological cellular and molecular mechanisms underlying AAA formation that would help to develop effective pharmacological therapies. In this review, pathophysiological aspects of AAA development with a special focus on mitochondrial dysfunction and genetic associations were discussed.

Role of Periodontal Infection, Inflammation and Immunity in Atherosclerosis

BACKGROUND

Inflammation plays a major role in the development and progression of cardiovascular disease (CVD) morbidity and mortality. The well-established relationship between periodontal disease (PD) and CVD may be causal. Left untreated, PD can lead to high systemic inflammation, thus contributing to inflammatory CVD, such as atherosclerosis. Multiple mechanisms have been proposed to elucidate the causal relationship between PD and its contribution to CVD.

OBJECTIVE

This review article highlights the current evidence supporting the role of PD in the development and progression of atherosclerosis.

METHODS

After creating a list of relevant medical subject heading (MeSH) terms, a systematic search within PubMed in English for each MeSH term between 2000 and 2019 was used to generate evidence for this review article.

CONCLUSION

There is overwhelming evidence in the current literature that supports an association between PD and CVD that is independent of known CVD risk factors. However, the supporting evidence that PD directly causes CVD in humans continues to remain elusive. Multiple biologically plausible mechanisms have been proposed and investigated, yet most studies are limited to mouse models and in vitro cell cultures. Additional studies testing the various proposed mechanisms in longitudinal human studies are required to provide deeper insight into the mechanistic link between these 2 related diseases.

Porphyromonas gingivalis and Its Systemic Impact: Current Status

The relationship between periodontitis and systemic diseases, notably including atherosclerosis and diabetes, has been studied for several years. Porphyromonas gingivalis, a prominent component of oral microorganism communities, is the main pathogen that causes periodontitis. As a result of the extensive analysis of this organism, the evidence of its connection to systemic diseases has become more apparent over the last decade. A significant amount of research has explored the role of Porphyromonas gingivalis in atherosclerosis, Alzheimer's disease, rheumatoid arthritis, diabetes, and adverse pregnancy outcomes, while relatively few studies have examined its contribution to respiratory diseases, nonalcoholic fatty liver disease, and depression. Here, we provide an overview of the current state of knowledge about Porphyromonas gingivalis and its systemic impact in an aim to inform readers of the existing epidemiological evidence and the most recent preclinical studies. Additionally, the possible mechanisms by which Porphyromonas gingivalis is involved in the onset or exacerbation of diseases, together with its effects on systemic health, are covered. Although a few results remain controversial, it is now evident that Porphyromonas gingivalis should be regarded as a modifiable factor for several diseases.

The oral health status of patients with peripheral vascular disorders: A systematic review

Objectives

Periodontal disease and tooth loss were found to be associated with several peripheral vascular disorders. Nonetheless, an evaluation of the literature on the broader domains of oral health in individuals with peripheral vascular disorders is lacking. This systematic review aims to collate the current evidence on the oral health status of individuals with peripheral vascular disorders.

Methods

Five electronic databases were searched for studies assessing oral health parameters in individuals with peripheral vascular disorders. Outcome measures considered were periodontal health, dentition status, caries indices, oral prostheses, oral pathologies and oral hygiene behaviours. The Newcastle-Ottawa scale was used to appraise the quality of the studies.

Results

From 3025 records identified, 24 studies involving 1232 participants with peripheral vascular disorders were included in this review. In nine studies, periodontitis was significantly more prevalent in peripheral vascular disorders compared to non-peripheral vascular disorders participants. A further six studies reported individuals with peripheral vascular disorders also had significantly fewer teeth and increased rates of edentulism. Only one study reported a higher incidence of dental caries in peripheral vascular disorders participants. Other aspects of oral health such as oral prosthesis, oral pathology and oral hygiene behaviours were seldom assessed.

Conclusions

The scarcity of studies reporting on broader domains limited our ability to arrive at a conclusion regarding the oral health status of individuals with peripheral vascular disorders. Future studies ought to assess these domains in individuals with peripheral vascular disorders and controls to gain a more complete understanding of oral health and its potential association with peripheral vascular disorders.

Further evidence on the relationship between abdominal aortic aneurysm and periodontitis: A cross-sectional study

BACKGROUND

Periodontitis is a chronic inflammatory disease characterized by Gram-negative bacteria responsible for the degradation of tissues surrounding tooth. Moreover, periopathogens can invade the bloodstream, disseminate and promote cardiovascular disease, such as the link between Porphyromonas gingivalis and atherosclerosis. The aim of this study was to explore the relationship between the severity of periodontitis and of abdominal aortic aneurysm (AAA).

METHODS

This cross-sectional study compared patients with stable AAA (n = 30) and patients with unstable AAA (n = 31) based on aortic diameter, growth rate, and eligibility for surgical intervention. Periodontal clinical parameters were recorded as well as the Periodontal Inflamed Surface Area and the Periodontal Index for Risk of Infectiousness (PIRI). Microbiological analyses were performed on saliva and supragingival and subgingival plaque. Quantification of Tannerella forsythia (Tf), Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), and Prevotella intermedia (Pi) was done by quantitative polymerase chain reaction.

RESULTS

The two AAA groups were homogeneous for age, sex, and most risk factors except hypertension and chronic obstructive pulmonary disease. Periodontal parameters were comparable but the proportion of patients with high PIRI scores was greater in those with unstable AAA (51.6% versus 23.3%). The probing depth (PD) and the proportion of PD >6 mm were positively correlated with AAA size and thrombus volume. Several associations were found between periopathogens such as Pg and AAA diameters and volumes, but no difference could be evidenced between stable and unstable AAA groups.

CONCLUSIONS

Periodontitis was highly prevalent in both stable and unstable AAA patients. Severe and progressive periodontitis (stage IV and grade C) tended to be more frequent in the group of patients with unstable AAA. Moreover, Pg was observed in all the samples (saliva, supragingival, and subgingival plaque) and was correlated with AAA diameters and volumes. The study evidenced potential relationships between periodontitis severity and size of AAA.

Microbiome composition comparison in oral and atherosclerotic plaque from patients with and without periodontitis

There is no conclusive evidence regarding a causal relationship between periodontitis and atherosclerosis. In this study, we examined the microbiome in the oral cavity and atheromatous plaques from atherosclerosis patients with or without periodontitis to investigate the role of oral bacteria in the formation of atheromatous plaques. We chose four patients with and without periodontitis, who had undergone carotid endarterectomy. Bacterial samples were extracted from the tongue surface, from periodontal pocket (during the oral examination), and from the atheromatous plaques (APs). We investigated the general and oral conditions from each patient and performed next-generation sequencing (NGS) analysis for all bacterial samples. There were no significant differences between both groups concerning general conditions. However, the microbiome patterns of the gingival pocket showed differences depending on the absence or presence of periodontitis, while those of the tongue surface were relatively similar. The microbiome pattern of the atheromatous plaques was entirely different from that on the tongue surface and gingival pocket, and oral bacteria were seldom detected. However, the microbiome pattern in atheromatous plaques was different in the presence or absence of periodontitis. These results suggested that oral bacteria did not affect the formation of atheromatous plaques directly.

Innovative application of nested PCR for detection of Porphyromonas gingivalis in human highly calcified atherothrombotic plaques

Atherothrombosis, leading to stroke and myocardial infarction, is responsible for most of the deaths in the world. An increased risk of atherothrombotic vascular events has been reported in patients with periodontitis. Periodontitis is a chronic multifactorial inflammatory disease, which involves a dysbiotic microbiota, and leads to a progressive destruction of the tooth-supporting apparatus. Transcient periodontal pathogen blood translocation, mainly bacteremia, has been associated with the severity of gingival inflammation. The identification of periodontal bacteria within atherothrombotic plaques is challenging and unpredictable. This review aims to summarize existing molecular technics for identifying periodontal microbiota in human atherothrombotic samples. A secondary objective is to describe a protocol for the identification of Porphyromonas gingivalis from highly calcified, atherothrombotic human samples that is based on our experience in translational cardiovascular research. Compared to direct real-time PCR, our protocol based on nested PCR has increased the detection of Porphyromonas gingivalis by 22.2% with good specificity.

Role of oral pathogens in the pathogenesis of intracranial aneurysm: review of existing evidence and potential mechanisms

Degeneration of intracranial aneurysm wall is under active research and recent studies indicate an increased risk of rupture of intracranial aneurysm among patients with periodontal diseases. In addition, oral bacterial DNA has been identified from wall samples of ruptured and unruptured aneurysms. These novel findings led us to evaluate if oral diseases could predispose to pathological changes seen on intracranial aneurysm walls eventually leading to subarachnoid hemorrhage. The aim of this review is to consider mechanisms on the relationship between periodontitis and aneurysm rupture, focusing on recent evidence.

Repeated Porphyromonas gingivalis W83 exposure leads to release pro-inflammatory cytokynes and angiotensin II in coronary artery endothelial cells

The role of Porphyromonas gingivalis (P. gingivalis) or its virulence factors, including lipopolysaccharide (LPS) not only has been related with periodontitis but also with endothelial dysfunction, a key mechanism involved in the genesis of atherosclerosis and hypertension that involving systemic inflammatory markers as angiotensin II (Ang II) and cytokines. This study compares the effect of repeated and unique exposures of P. gingivalis W83 LPS and live bacteria on the production and expression of inflammatory mediators and vasoconstrictor molecules with Ang II. Human coronary artery endothelial cells (HCAEC) were stimulated with purified LPS of P. gingivalis (1.0, 3.5 or 7.0 μg/mL) or serial dilutions of live bacteria (MOI 1: 100 - 1:0,1) at a single or repeated exposure for a time of 24 h. mRNA expression levels of AGTR1, AGTR2, IL-8, IL-1β and MCP-1 were determined by RT-qPCR, and IL-6, MCP-1, IL-8, IL-1β and GM-CSF levels were measured by flow cytometry, ELISA determined Ang II levels. Live bacteria in a single dose increased mRNA levels of AGTR1, and repeated doses increased mRNA levels of IL-8 and IL-1β (p < 0.05). Repeated exposure of live-P. gingivalis induced significant production IL-6, MCP-1 and GM-CSF (p < 0.05). Moreover, these MCP-1, IL-6 and GM-CSF levels were greater than in cells treated with single exposure (p < 0.05), The expression of AGTR1 and production of Ang II induced by live-P. gingivalis W83 showed a vasomotor effect of whole bacteria in HCAEC more than LPS. In conclusion, the findings of this study suggest that repeated exposure of P. gingivalis in HCAEC induces the activation of proinflammatory and vasoconstrictor molecules that lead to endothelial dysfunction being a key mechanism of the onset and progression of arterial hypertension and atherosclerosis.

Periodontitis and gingival bleeding associate with intracranial aneurysms and risk of aneurysmal subarachnoid hemorrhage

Oral bacteria DNA has been found in intracranial aneurysms (IA) and a high prevalence of periodontitis was reported in IA patients. We investigated whether periodontitis associates with IA formation and aneurysmal subarachnoid hemorrhage (aSAH). First, we compared in a case-control setting the prevalence of periodontal disease in IA patients (42 unruptured IA, 34 ruptured IA) and in age- and gender-matched controls (n = 70) from the same geographical area (Health 2000 Survey, BRIF8901). Next, we investigated whether periodontitis at baseline associated with aSAH in a 13-year follow-up study of 5170 Health 2000 Survey participants. Follow-up data was obtained from national hospital discharge and cause of death registries. Univariate analysis, logistic regression, and Cox-regression were used. Periodontitis (≥ 4mm gingival pocket) and severe periodontitis (≥ 6mm gingival pocket) were found in 92% and 49% of IA patients respectively and associated with IAs (OR 5.3, 95%CI 1.1–25.9, p < 0.000 and OR 6.3, 95%CI 1.3–31.4, p < 0.001, respectively). Gingival bleeding had an even stronger association, especially if detected in 4–6 teeth sextants (OR 34.4, 95%CI 4.2–281.3). Severe periodontitis in ≥ 3 teeth or gingival bleeding in 4–6 teeth sextants at baseline increased the risk of aSAH during follow-up (HR 22.5, 95%CI 3.6–139.5, p = 0.001 and HR 8.3, 95%CI 1.5–46.1, p = 0.015, respectively). Association of periodontitis and gingival bleeding with risk of IA development and aSAH was independent of gender, smoking status, hypertension, or alcohol abuse. Periodontitis and gingival bleeding associate with increased risk for IA formation and eventual aSAH. Further epidemiological and mechanistic studies are indicated.

Antithrombotic therapy in abdominal aortic aneurysm: beneficial or detrimental?

Abdominal aortic aneurysm (AAA) is a degenerative vascular pathology resulting in significant morbidity and mortality in older adults due to rupture and sudden death. Despite 150 000 new cases and nearly 15 000 deaths annually, the only approved treatment of AAA is surgical or endovascular intervention when the risk for aortic rupture is increased. The goal of the scientific community is to develop novel pharmaceutical treatment strategies to reduce the need for surgical intervention. Because most clinically relevant AAAs contain a complex structure of fibrin, inflammatory cells, platelets, and red blood cells in the aneurysmal sac known as an intraluminal thrombus (ILT), antithrombotic therapies have emerged as potential pharmaceutical agents for the treatment of AAA progression. However, the efficacy of these treatments has not been shown, and the effects of shrinking the ILT may be as detrimental as they are beneficial. This review discusses the prospect of anticoagulant and antiplatelet (termed collectively as antithrombotic) therapies in AAA. Herein, we discuss the role of the coagulation cascade and platelet activation in human and animal models of AAA, the composition of ILT in AAA, a possible role of the ILT in aneurysm stabilization, and the implications of antithrombotic drugs in AAA treatment.

Oral hygiene and periodontal conditions in the Chinese patients with aortic aneurysm

Background

This cross-sectional study aims to evaluate the association of periodontal conditions and oral hygiene habits in the Chinese patients with an aortic aneurysm (AA).

Methods

A questionnaire and periodontal examinations were carried out in the AA patients and non-AA volunteers recruited from the Center for Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University between August 2011 and June 2016. General information (e.g., height and weight), history of systemic diseases, and oral hygiene habits (e.g., brushing methods and regular oral examinations) were collected in the self-reported survey. Periodontal examinations, such as plaque index and bleeding index, were conducted in all the subjects. The correlation between periodontal indices and AA was further explored using univariate and multivariate analyses.

Results

Our analyses revealed that 87.6% of AA patients have chronic periodontitis, which is significantly higher than that of the non-AA patients (55.8%). In addition, AA patients demonstrated more severe periodontal damages with 69.3% moderate and severe periodontitis, compared to only 16.0% in the non-AA group. Using AA as the dependent variable and all the potential risk factors as covariates (e.g., gender, age, smoking, obesity, diabetes, hypertension, and hyperlipidemia), a logistic regression analysis was performed to show clinical attachment loss (CAL) being an independent risk factor for AA (OR = 2.309, 95% CI: 1.623–3.284, p = 0.000). In comparison with the non-AA patients, more AA patients have poor oral hygiene habits and don’t have regular dental appointments for supra-gingival cleaning.

Conclusion

Poor periodontal condition and dental hygiene were identified in the AA patients, suggesting that periodontitis-induced CAL may play a role in AA disease mechanisms.

Association of Tongue Bacterial Flora and Subtypes of Liver-Fire Hyperactivity Syndrome in Hypertensive Patients

Structural changes in symbiotic human microorganisms can affect host phenotype. Liver-fire hyperactivity syndrome (LFHS) presents as bitter taste, halitosis, xerostomia, odontalgia, and other oral symptoms. LFHS is associated with hypertension (EH). In this study, tongue flora was analyzed to further understand the intrinsic relationship between tongue flora and LFHS. Samples of tongue coating, from 16 patients with EH-LFHS, 16 with EH-non-LFHS, and 16 controls, were obtained; then, 16S rRNA variable (V3-V4) regions were amplified and sequenced by MiSeq PE300 Sequencing. Tag clustering and Operational Taxonomic Units (OTUs) abundance analysis were used to compare the OTU sequence with the 16S database. The species were classified, and diversity and structure of the bacterial flora were compared between the three groups. Alpha diversity analysis, including Observed Species index and Chao index, indicated significantly higher richness of species in patients with EH-LFHS (p < 0.05). Higher phylogenetic diversity, in patients with EH-non-LFHS, indicates greater differences in evolutionary history than in patients with EH-LFHS. Streptococcus, Rothia, Neisseria, and Sphingomonas were the most prevalent in patients with EH-LFHS, differed from the other two groups. This indicates that richer bacterial diversity, and structure associated with EH-LFHS, may affect the occurrence, development, and outcome of hypertension and syndrome subtypes recognized by TCM.

An Experimental Model of Peripheral Vascular Disease Involving the Intravenous Injection of Oral Bacteria

Objective: The purpose of this study was to observe the direct effects of oral bacteria, such as Porphyromonas gingivalis (Pg) and Treponema denticola (Td), on the peripheral vasculature. Materials and Methods: Beagles were directly injected (at various doses) with Pg or Td. Each leg vein was exposed, ligated at proximal and distal sites, and then injected with bacteria diluted with sterile saline. The collected vascular tissue was examined microscopically, and samples of the vascular tissue and blood were cultured and then subjected to the polymerase chain reaction (PCR) in order to detect the bacterial deoxyribonucleic acid (DNA). Results: No genes of the injected bacteria were detected in the Td-inoculated blood or vascular tissue samples collected 2 weeks after the injection. The Pg gene was also not detected in the blood samples collected 4 weeks after the injection although it was detected in the vascular tissue using PCR. Microscopic examinations showed that the inflammatory reactions in the perivascular tissue increased in a bacterial dose-dependent manner, as expected. Conclusion: We observed the direct effects of oral bacteria on vascular tissue. Further studies are needed to investigate the correlations between oral bacteria and systemic diseases. (This article is a translation of Jpn J Phlebol 2015; 26: 41-6.).

Periodontal bacterial invasion and infection: contribution to atherosclerotic pathology

OBJECTIVE

The objective of this review was to perform a systematic evaluation of the literature reporting current scientific evidence for periodontal bacteria as contributors to atherosclerosis.

METHODS

Literature from epidemiological, clinical and experimental studies concerning periodontal bacteria and atherosclerosis were reviewed. Gathered data were categorized into seven "proofs" of evidence that periodontal bacteria: 1) disseminate from the oral cavity and reach systemic vascular tissues; 2) can be found in the affected tissues; 3) live within the affected site; 4) invade affected cell types in vitro; 5) induce atherosclerosis in animal models of disease; 6) non-invasive mutants of periodontal bacteria cause significantly reduced pathology in vitro and in vivo; and 7) periodontal isolates from human atheromas can cause disease in animal models of infection.

RESULTS

Substantial evidence for proofs 1 to 6 was found. However, proof 7 has not yet been fulfilled.

CONCLUSIONS

Despite the lack of evidence that periodontal bacteria obtained from human atheromas can cause atherosclerosis in animal models of infection, attainment of proofs 1 to 6 provides support that periodontal pathogens can contribute to atherosclerosis.

Periodontal bacterial invasion and infection: contribution to atherosclerotic pathology

OBJECTIVE

The objective of this review was to perform a systematic evaluation of the literature reporting current scientific evidence for periodontal bacteria as contributors to atherosclerosis.

METHODS

Literature from epidemiological, clinical and experimental studies concerning periodontal bacteria and atherosclerosis were reviewed. Gathered data were categorized into seven "proofs" of evidence that periodontal bacteria: 1) disseminate from the oral cavity and reach systemic vascular tissues; 2) can be found in the affected tissues; 3) live within the affected site; 4) invade affected cell types in vitro; 5) induce atherosclerosis in animal models of disease; 6) non-invasive mutants of periodontal bacteria cause significantly reduced pathology in vitro and in vivo; and 7) periodontal isolates from human atheromas can cause disease in animal models of infection.

RESULTS

Substantial evidence for proofs 1 to 6 was found. However, proof 7 has not yet been fulfilled.

CONCLUSIONS

Despite the lack of evidence that periodontal bacteria obtained from human atheromas can cause atherosclerosis in animal models of infection, attainment proofs 1 to 6 provides support that periodontal pathogens can contribute to atherosclerosis.

The Epidemiologic and Clinical Findings of Patients with Buerger Disease

BACKGROUND

Buerger disease is a nonatherosclerotic peripheral arterial disease, which is mostly observed in young male smokers. Buerger disease is characterized by the observation of peripheral arterial occlusion by angiography. The condition may be caused by microembolization in the small-sized arteries of the distal extremities. Buerger disease is diagnosed based on the Shionoya's clinical diagnostic criteria, which include: (1) a history of smoking, (2) onset before the age of 50 years, (3) the presence of infrapopliteal arterial occlusions, (4) either upper limb involvement or phlebitis migrans, and (5) the absence of atherosclerotic risk factors other than smoking. Several studies have reported that oral bacterial infections (periodontitis) could activate the onset of Buerger disease. In this study, we report the epidemiologic and clinical manifestations of patients with Buerger disease.

METHODS

Fifty-eight patients who were surgically treated between July 1989 and June 2014 at Tokyo Medical and Dental University Hospital were enrolled in this study. All of the patients clinically diagnosed with Buerger disease based on Shionoya's clinical diagnostic criteria. Fifty-five male and 3 female patients were treated. The mean age of the patients was 48 years (range, 21-73 years).

RESULTS

All of the patients were either smokers or had a history of smoking. The mean Brinkman index score was 780 (range, 150-1,640). Their mean age at the onset of Buerger disease was 38 years (range, 21-50). The arterial lesions extended to the femoral arteries in 25% of cases, to the iliac arteries in 8% and to the abdominal aorta and/or visceral arteries in 6% of cases. Upper limb involvement, including cyanosis, paleness, and gangrene, was obvious in 84% of patients, and phlebitis migrans was recognized in 34%. The lower extremities symptoms involved intermittent claudication in 23% of the patients, rest pain in 13% of the patients, and ulceration or gangrene in 64% of the patients. Fifteen patients had undergone surgical arterial reconstruction, 4 patients had received endovascular therapy, 33 patients had undergone lumbar sympathectomy and 8 patients had undergone thoracic sympathectomy. Twenty percent of the patients needed minor limb amputations, and 4% required major limb amputations. In the patients who were examined for their oral conditions, periodontitis corresponding to grades B (moderate periodontitis), C (severe periodontitis), and D (edentulous patients) was revealed in 31%, 56%, and 13% of the patients, respectively.

CONCLUSIONS

More than half of the Buerger disease patients in this study were suffering from severe periodontitis. It is possible that not only the cessation of smoking, but also the improvement of periodontal care could improve the clinical symptoms related to Buerger disease.

Periodontal Disease-Induced Atherosclerosis and Oxidative Stress

Periodontal disease is a highly prevalent disorder affecting up to 80% of the global population. Recent epidemiological studies have shown an association between periodontal disease and cardiovascular disease, as oxidative stress plays an important role in chronic inflammatory diseases such as periodontal disease and cardiovascular disease. In this review, we focus on the mechanisms by which periodontopathic bacteria cause chronic inflammation through the enhancement of oxidative stress and accelerate cardiovascular disease. Furthermore, we comment on the antioxidative activity of catechin in atherosclerosis accelerated by periodontitis.

Propionibacterium acnes Recovered from Atherosclerotic Human Carotid Arteries Undergoes Biofilm Dispersion and Releases Lipolytic and Proteolytic Enzymes in Response to Norepinephrine Challenge In Vitro

In the present study, human atherosclerotic carotid arteries were examined following endarterectomy for the presence of the Gram-positive bacterium Propionibacterium acnes and its potential association with biofilm structures within the arterial wall. The P. acnes 16S rRNA gene was detectable in 4 of 15 carotid artery samples, and viable P. acnes was one among 10 different bacterial species recoverable in culture. Fluorescence in situ hybridization analysis of 5 additional atherosclerotic carotid arteries demonstrated biofilm bacteria within all samples, with P. acnes detectable in 4 samples. We also demonstrated that laboratory-grown cultures of P. acnes biofilms were susceptible to induction of a biofilm dispersion response when challenged with physiologically relevant levels of norepinephrine in the presence of iron-bound transferrin or with free iron. The production and release of lipolytic and proteolytic extracellular enzymes by P. acnes were shown to increase in iron-induced dispersed biofilms, and these dispersion-induced P. acnes VP1 biofilms showed increased expression of mRNAs for the triacylglycerol lipases PPA2105 and PPA1796 and the hyaluronate lyase PPA380 compared to that in untreated biofilms. These results demonstrate that P. acnes can infect the carotid arteries of humans with atherosclerosis as a component of multispecies biofilms and that dispersion is inducible for this organism, at least in vitro, with physiologically relevant levels of norepinephrine resulting in the production and release of degradative enzymes.

Acute cervical artery dissection after a dental procedure due to a second inferior molar infection

Periodontal infections might represent one of the causative factors for cervical artery dissection. We present a case of a 49-year-old woman admitted due to headache. The patient had been suffering from a right second inferior molar infection with a cervical phlegmon for 1 week prior to admission. On 2 October 2014, the patient went to the dentist and a molar extraction was performed in the morning. In the afternoon, the patient began to experience right hemifacial pain that progressed towards an intense and bilateral headache. Neurological status at the time of admission revealed right miosis, ptosis and conjuntival hyperaemia. A CT angiography showed a right internal carotid artery dissection provoking a high-degree stenosis. The relationship between periodontal infection and vascular disease has been previously presented. Microbial agents may directly, and inflammatory and immunological host response indirectly, influence inflammatory changes in cervical arteries favouring dissections with minor traumas.

Comparative study of abdominal and thoracic aortic aneurysms: their pathogenesis and a gingival fibroblasts-based ex vivo treatment

Aortic aneurysms (AAs) consist of slow proteolysis and loss of both collagen and elastin matrix in the aorta wall, leading to wall dilation, weakening and rupture in well-advanced lesions. This can occur in both abdominal aorta (Abdominal Aortic Aneurysm: AAA) and thoracic aorta (Thoracic Aortic Aneurysm: TAA). To date, no non-surgical therapy has been proposed to slow or stop AA progression. Previously published preclinical studies from our team using an aneurysm rabbit model showed a promising concept for treatment of AAs with gingival fibroblast (GFs) which are readily available cells. In this study, we investigated the possible tissue repair of human AAAs and TAAs using ex vivo models co-cultured with GFs. Histological analysis showed that TAA and AAA are two distinct pathologies. Both lesions presented destruction of the aorta wall, highly evidenced in AAA samples. The results have confirmed the presence of the bacterial Porphyromonas gingivalis (Pg) protein in all AAA samples, but not in TAA samples, indicating the possible role of an infectious factor in the developing and progression of AAA lesions compared to TAA. The co-culture of GFs with AA lesions shows increased expression of TIMP-1, the inhibitor of the aneurysm severity marker MMP-9. Our study indicates that GFs might ameliorate aorta wall reestablishment in both AA types by their regenerative and immunomodulatory capacities. It also demonstrates the possible infectious cause of AAA compared with TAA that may explain their different behavior.

Influence of periodontitis on abdominal aortic aneurysms

Periodontitis is known to be a risk factor for abdominal aortic aneurysm (AAA). However, the influence of periodontitis on AAA development is to be elucidated. This article is to review the relationship between periodontitis and AAA. We focused on the roles of specific periodontopathic bacteria in AAA, matrix metalloproteinases and toll-like receptors in the pathophysiology in the section of experimental analysis. Furthermore, we showed clinical data of periodontitis in patients with AAA. We concluded that periodontal pathogens play a critical role in the AAA development.

Bacteria present in carotid arterial plaques are found as biofilm deposits which may contribute to enhanced risk of plaque rupture

Atherosclerosis, a disease condition resulting from the buildup of fatty plaque deposits within arterial walls, is the major underlying cause of ischemia (restriction of the blood), leading to obstruction of peripheral arteries, congestive heart failure, heart attack, and stroke in humans. Emerging research indicates that factors including inflammation and infection may play a key role in the progression of atherosclerosis. In the current work, atherosclerotic carotid artery explants from 15 patients were all shown to test positive for the presence of eubacterial 16S rRNA genes. Density gradient gel electrophoresis of 5 of these samples revealed that each contained 10 or more distinct 16S rRNA gene sequences. Direct microscopic observation of transverse sections from 5 diseased carotid arteries analyzed with a eubacterium-specific peptide nucleic acid probe revealed these to have formed biofilm deposits, with from 1 to 6 deposits per thin section of plaque analyzed. A majority, 93%, of deposits was located proximal to the internal elastic lamina and associated with fibrous tissue. In 6 of the 15 plaques analyzed, 16S rRNA genes from Pseudomonas spp. were detected. Pseudomonas aeruginosa biofilms have been shown in our lab to undergo a dispersion response when challenged with free iron in vitro. Iron is known to be released into the blood by transferrin following interaction with catecholamine hormones, such as norepinephrine. Experiments performed in vitro showed that addition of physiologically relevant levels of norepinephrine induced dispersion of P. aeruginosa biofilms when grown under low iron conditions in the presence but not in the absence of physiological levels of transferrin.

IMPORTANCE

The association of bacteria with atherosclerosis has been only superficially studied, with little attention focused on the potential of bacteria to form biofilms within arterial plaques. In the current work, we show that bacteria form biofilm deposits within carotid arterial plaques, and we demonstrate that one species we have identified in plaques can be stimulated in vitro to undergo a biofilm dispersion response when challenged with physiologically relevant levels of norepinephrine in the presence of transferrin. Biofilm dispersion is characterized by the release of bacterial enzymes into the surroundings of biofilm microcolonies, allowing bacteria to escape the biofilm matrix. We believe these enzymes may have the potential to damage surrounding tissues and facilitate plaque rupture if norepinephrine is able to stimulate biofilm dispersion in vivo. This research, therefore, suggests a potential mechanistic link between hormonal state and the potential for heart attack and stroke.

Periodontal pathogens and atherosclerosis: implications of inflammation and oxidative modification of LDL

Inflammation is well accepted to play a crucial role in the development of atherosclerotic lesions, and recent studies have demonstrated an association between periodontal disease and cardiovascular disease. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, causative agents of destructive chronic inflammation in the periodontium, can accelerate atheroma deposition in animal models. Emerging evidence suggests that vaccination against virulence factors of these pathogens and anti-inflammatory therapy may confer disease resistance. In this review, we focus on the role of inflammatory mechanisms and oxidative modification in the formation and activation of atherosclerotic plaques accelerated by P. gingivalis or A. actinomycetemcomitans in an ApoE-deficient mouse model and high-fat-diet-fed mice. Furthermore, we examine whether mucosal vaccination with a periodontal pathogen or the anti-inflammatory activity of catechins can reduce periodontal pathogen-accelerated atherosclerosis.

High incidence of periodontitis in Japanese patients with abdominal aortic aneurysm

Periodontitis is known to be a risk factor for abdominal aortic aneurysm (AAA). However, the influence of periodontitis on AAA in Japanese patients has not yet been elucidated. The aim of this clinical investigation was to assess the relationship between periodontal bacterial burden in AAA patients.We studied 12 AAA patients and 24 age- and sex-matched non-AAA cardiovascular patients. We examined periodontitis and the presence of the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia in oral samples using polymerase chain reaction assays.We found that the AAA patients had deeper pocket depth compared to the non-AAA patients (3.53 ± 0.38 mm versus 2.67 ± 0.17 mm, P < 0.05). However, the populations of periodontal bacteria were comparable between the two groups. Periodontitis may have a greater effect on aneurysm progression compared to other cardiovascular diseases.

Update on abdominal aortic aneurysm research: from clinical to genetic studies

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta with a diameter of at least 3.0 cm. AAAs are often asymptomatic and are discovered as incidental findings in imaging studies or when the AAA ruptures leading to a medical emergency. AAAs are more common in males than females, in individuals of European ancestry, and in those over 65 years of age. Smoking is the most important environmental risk factor. In addition, a positive family history of AAA increases the person's risk for AAA. Interestingly, diabetes has been shown to be a protective factor for AAA in many large studies. Hallmarks of AAA pathogenesis include inflammation, vascular smooth muscle cell apoptosis, extracellular matrix degradation, and oxidative stress. Autoimmunity may also play a role in AAA development and progression. In this Outlook paper, we summarize our recent studies on AAA including clinical studies related to surgical repair of AAA and genetic risk factor and large-scale gene expression studies. We conclude with a discussion on our research projects using large data sets available through electronic medical records and biobanks.

Incidence of periodontitis in Japanese patients with cardiovascular diseases: a comparison between abdominal aortic aneurysm and arrhythmia

Although there is a link between periodontitis and cardiovascular disease (CVD), the influence of periodontitis on CVD is unclear. The aim of this study was to assess the relationship between periodontal bacterial burden and CVD. We studied 142 patients with tachyarrhythmia (TA) and 25 patients with abdominal aortic aneurysm (AAA). We examined periodontitis and the presence of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Prevotella intermedia in the patients' saliva and subgingival plaque using PCR. We also measured serum antibody titers against the pathogens using ELISA. We found that the patients with AAA had fewer remaining teeth (14.6 ± 2.0 vs. 20.9 ± 0.7, P < 0.05) and deeper pocket depth (3.01 ± 0.26 vs. 2.52 ± 0.05 mm, P < 0.05) compared to the TA patients. The existence of each periodontal bacterium in their saliva or subgingival plaque and serum antibody titers was comparable between the two groups. Periodontitis may have a larger affect on aneurysm progression compared to arrhythmia.

Periodontitis as a risk factor of atherosclerosis

Over the last two decades, the amount of evidence corroborating an association between dental plaque bacteria and coronary diseases that develop as a result of atherosclerosis has increased. These findings have brought a new aspect to the etiology of the disease. There are several mechanisms by which dental plaque bacteria may initiate or worsen atherosclerotic processes: activation of innate immunity, bacteremia related to dental treatment, and direct involvement of mediators activated by dental plaque and involvement of cytokines and heat shock proteins from dental plaque bacteria. There are common predisposing factors which influence both periodontitis and atherosclerosis. Both diseases can be initiated in early childhood, although the first symptoms may not appear until adulthood. The formation of lipid stripes has been reported in 10-year-old children and the increased prevalence of obesity in children and adolescents is a risk factor contributing to lipid stripes development. Endothelium damage caused by the formation of lipid stripes in early childhood may lead to bacteria penetrating into blood circulation after oral cavity procedures for children as well as for patients with aggressive and chronic periodontitis.

Atherosclerosis and Alzheimer--diseases with a common cause? Inflammation, oxysterols, vasculature

BACKGROUND

Aging is accompanied by increasing vulnerability to pathologies such as atherosclerosis (ATH) and Alzheimer disease (AD). Are these different pathologies, or different presentations with a similar underlying pathoetiology?

DISCUSSION

Both ATH and AD involve inflammation, macrophage infiltration, and occlusion of the vasculature. Allelic variants in common genes including APOE predispose to both diseases. In both there is strong evidence of disease association with viral and bacterial pathogens including herpes simplex and Chlamydophila. Furthermore, ablation of components of the immune system (or of bone marrow-derived macrophages alone) in animal models restricts disease development in both cases, arguing that both are accentuated by inflammatory/immune pathways. We discuss that amyloid β, a distinguishing feature of AD, also plays a key role in ATH. Several drugs, at least in mouse models, are effective in preventing the development of both ATH and AD. Given similar age-dependence, genetic underpinnings, involvement of the vasculature, association with infection, Aβ involvement, the central role of macrophages, and drug overlap, we conclude that the two conditions reflect different manifestations of a common pathoetiology.

MECHANISM

Infection and inflammation selectively induce the expression of cholesterol 25-hydroxylase (CH25H). Acutely, the production of 'immunosterol' 25-hydroxycholesterol (25OHC) defends against enveloped viruses. We present evidence that chronic macrophage CH25H upregulation leads to catalyzed esterification of sterols via 25OHC-driven allosteric activation of ACAT (acyl-CoA cholesterol acyltransferase/SOAT), intracellular accumulation of cholesteryl esters and lipid droplets, vascular occlusion, and overt disease.

SUMMARY

We postulate that AD and ATH are both caused by chronic immunologic challenge that induces CH25H expression and protection against particular infectious agents, but at the expense of longer-term pathology.

Quantification of periodontal pathogens in vascular, blood, and subgingival samples from patients with peripheral arterial disease or abdominal aortic aneurysms

BACKGROUND

The aim of this investigation is to quantify periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Campylobacter rectus, and Tannerella forsythia) in vascular, blood, and subgingival samples. As a secondary objective, two molecular bacterial identification methods (nested polymerase chain reaction [PCR] and quantitative PCR [qPCR]) are compared.

METHODS

Seventy consecutive patients provided a vascular lesion, a blood sample, and 36 subgingival samples. Bacterial DNA was extracted, and qPCR was used to determine the prevalence and amounts of the target pathogens in each sample. Nested PCR was performed only in the samples from vascular lesions. Periodontal examination was performed in 42 patients. Mann-Whitney U or χ(2) tests were used to compare microbiologic results according to periodontal diagnosis.

RESULTS

All targeted periodontal pathogens (A. actinomycetemcomitans, P. gingivalis, T. forsythia, or C. rectus) were detected in subgingival samples, with a prevalence rate of 72.2%, 47.2%, 74.3%, and 82.9%, respectively. In 7.1% and 11.4% of vascular and blood samples, bacterial DNA was detected. One patient was positive for A. actinomycetemcomitans in the three types of samples. No differences were found in the levels of targeted bacteria when comparing patients with and without periodontitis. Prevalence rates obtained with nested PCR were significantly higher than those obtained with qPCR.

CONCLUSIONS

The presence of A. actinomycetemcomitans was demonstrated in vascular, blood, and subgingival samples in one of 36 patients. These results, although with a very low frequency, may support the hypothesis of a translocation of periodontal pathogens from subgingival microbiota to the bloodstream and then to atheromatous plaques in carotid or other peripheral arteries. Nested PCR is not an adequate method for identifying DNA of periodontal pathogens in low quantities because of the high number of false-negative results.