Detection of specific periodontal microorganisms from bacteraemia samples after periodontal therapy using molecular-based diagnostics

Chronic Lipopolysaccharide Exposure Causes AD-Like Pathology in Male Mice With Intact Blood-Brain Barrier

Chronic inflammatory conditions like periodontitis and inflammatory bowel disease (IBD) are reported to contribute to the pathogenesis of late-onset Alzheimer's disease (AD). Gram-negative bacteria are the main bacterial species causing oral and gut mucosal infections. Lipopolysaccharide (LPS) is a major inflammation-inducing molecule in Gram-negative bacteria. LPS derived from the oral bacterium Porphyromonas gingivalis exhibits heterogeneous tetra-acylated and penta-acylated lipid A, while LPS from Escherichia coli exhibits the classical hexa-acylated lipid A. Whether P. gingivalis-LPS and E. coli-LPS play a similar role in the progression of late-onset AD is unknown. Using adult, wild-type C57BL/6J mice to mimic the adult population without genetically determined predisposition to AD, we showed that chronic inflammation induced by a 28-day, subcutaneous infusion of P. gingivalis-LPS or E. coli-LPS can lead to neuroinflammation and AD-like cognitive decline and pathology in male mice. At this relatively early stage (4 weeks) of chronic inflammation when the blood-brain barrier is intact, both P. gingivalis-LPS and E. coli-LPS cause neuroinflammation through Toll-like receptor 4 (TLR4) and Toll-like receptor 2 (TLR2) expressed at microglia in the brain. Notably, only E. coli-LPS induces significant inflammatory responses systemically. In short, our results suggest that chronic P. gingivalis-LPS release (occurring in chronic periodontitis) or E. coli-LPS release (occurring in IBD) could harm the brain before the blood-brain barrier is disrupted; continuous local P. gingivalis-LPS release might do harm to the brain before exhibiting adverse effects systemically.

Bacterial translocation signatures and subgingival microbiome in individuals with periodontitis

OBJECTIVES

To determine bacterial blood translocation signatures and their association with the subgingival microbiota in individuals with and without periodontitis.

MATERIALS AND METHODS

Cross-sectional study. DNA was extracted from blood and subgingival samples of individuals with periodontitis (n = 21) and control volunteers (n = 24). Subgingival microbiota was explored by 16 S rRNA gene sequencing. Detection frequency and loads of total bacteria, Porphyromonas gingivalis (Pg), Porphyromonas endodontalis (Pe) and Fusobacterium nucleatum (Fn) were determined in all samples using quantitative polymerase chain reaction (qPCR). The statistical analysis was performed using STATA 16.

RESULTS

Subgingival samples from individuals with periodontitis presented higher relative abundance of Prevotella intermedia, F. nucleatum subsp. vincentii, Treponema sp. HMT 237, Alloprevotella tannerae, Filifactor alocis, Pg, Treponema denticola and Pe, and higher loads of total bacteria, Pg, Pe and Fn, compared to the control group (p < 0.001). While Pg and Fn were not detected in blood, Pe was detected in 95% of individuals with periodontitis and 83% of the control ones (p = 0.205), with higher loads in blood samples from periodontitis (p = 0.034). No significant correlation was found between subgingival bacterial loads and blood loads of Pe in periodontitis and control groups (p > 0.05).

CONCLUSIONS

Individuals with periodontitis presented higher relative abundance and loads of periodontal bacteria in subgingival samples and higher Pe loads in blood samples, although further research is needed to understand the correlation between subgingival and blood bacterial loads.

CLINICAL RELEVANCE

The present study showed higher loads of Pe in the blood of individuals with periodontitis, suggesting potential extraoral dissemination and a linking mechanism with several systemic diseases.

Bacteraemia and proinflammatory response after non-surgical periodontal therapy and adjunctive antibiotics in patients with recent acute coronary syndrome

INTRODUCTION

This study compares the incidence of bacteraemia and proinflammatory cytokines in short and long periods after non-surgical periodontal therapy involving premedication with amoxicillin (AMX) followed by AMX and metronidazole (MTZ) in patients with Acute Coronary Syndrome (ACS).

METHODS

This pilot study included twelve individuals with periodontitis and recent ACS. Six patients were treated with subgingival instrumentation (SI), and six with supragingival ultrasonic scaling (US). Amoxicillin 2 g was administered as premedication in the first visit, followed by AMX-MTZ for one week. The incidence of bacteraemia was evaluated using hemoculture, qPCR, and next-generation sequencing (NGS) before the treatment (t0) and 30 min later (t1) (quadrants 1 and 2), and after one-week, pre-post-treatment samples were taken from the re-maining quadrants (t3 and t4). Proinflammatory cytokines were evaluated in serum at baseline (t0), one week (t1), and six months (t5).

RESULTS

Bacteraemia was low in 16.6 %, similar in both treatment groups. Porphyromonas gingivalis and Desulfobulbus oralis (16.6 %), Filifactor alocis, Eubacterium saphenum, Eubacterium brachy (8.3 %) were identified with qPCR. NGS was only detected in a single patient; at time t0, bacteria were more diverse than at t3 and were associated with the phyla Bacteroidetes and Proteobacteria. Interestingly, many clones observed in blood were non-oral. After treatment, all cytokines were reduced significantly in the SI group in the long term (p< 0.05).

CONCLUSIONS

Periodontal therapy reduced bacteremia: despite the antibiotic regimen, bacteria remained in peripheral blood, which could be associated with antimicrobial resistance. SI produced a more efficient reduction of proinflammatory cytokines after periodontal treatment in individuals with ACS.

Periodontal Treatment to Improve General Health and Manage Systemic Diseases

Periodontitis is increasingly recognized for its role in overall health and its associations with systemic conditions. Shared etiological factors, including microbiological, immunological, genetic, and environmental influences, have prompted interest in the potential impact of periodontal therapy on broader health outcomes. The oral microbiome plays a key role in the pathogenesis of periodontitis, with microbial imbalances (dysbiosis) contributing to inflammation and systemic disease progression. Additionally, immune responses to periodontal infection, such as chronic inflammation and dysregulated immune activity, are central to linking periodontitis with conditions like diabetes, cardiovascular disease, and autoimmune disorders. This chapter explores the connections between periodontal treatment and systemic diseases, such as diabetes, rheumatoid arthritis, cardiovascular disease, chronic kidney disease, Alzheimer's disease, digestive disorders, and respiratory disease. It also reviews the current research on the mechanisms, including microbial and immune factors, that underlie these associations. By emphasizing the role of periodontal health, the oral microbiome, and immune regulation in disease prevention and management, this chapter underscores the importance of integrated healthcare approaches to improve patient outcomes.

Periodontal Molecular Diagnostics: State of Knowledge and Future Prospects for Clinical Application

Periodontitis leads to immunologically mediated loss of periodontium and, if untreated, can result in tooth loss. Periodontal diseases are the most prevalent in the world and have a very strong impact on patients' well-being and general health. Their treatment generates enormous costs. Given the above, precise, prompt, and predictive diagnosis of periodontal disease is of paramount importance for clinicians. The aim of the study was to summarize the state-of-the-art knowledge of molecular periodontal diagnostics and the utility of its clinical application. There is a great need to have diagnostic tests that not only describe the periodontal destruction that has occurred in the tissues but also allow clinicians to detect disease at a subclinical level before the changes occur. A test that would enable clinicians to follow the course of the disease and detect areas prone to exacerbation could be used to evaluate the effectiveness of ongoing periodontal therapies. Unfortunately, there is no such diagnostic method yet. A hopeful prospect is molecular diagnostics. There are numerous studies on biomarkers of periodontal disease. Point-of-care tests are also emerging. There are possibilities for processing large biological datasets (omics data). However, all of the above have a minor role in the overall single-patient diagnostics process. Despite advances in microbiological, molecular, and genetic research, the basis of periodontal diagnosis is still clinical examination enriched by the evaluation of radiological images.

Exploring the oral-gut linkage: Interrelationship between oral and systemic diseases

The oral cavity harbors a diverse microbiota that plays a significant role in maintaining homeostasis. Disruption of this balance can lead to various oral diseases, including periodontitis. Accumulating evidence suggests a connection between periodontitis and extra-oral diseases such as cardiovascular disease, rheumatoid arthritis, obesity, and diabetes. During periodontitis, oral bacteria enter the bloodstream directly, impacting extra-oral organs. Furthermore, recent studies have uncovered another pathway, the direct oral-gut axis, where oral bacteria translocate to the gut through an enteral route, influencing gut microbiota and metabolism. Oral pathobionts associated with exacerbation of periodontal disease are implicated in gut pathology, including inflammatory bowel disease and colorectal cancer through ectopic gut colonization. Furthermore, oral bacteria can provoke host immune responses, leading to colitis and other inflammatory diseases. Conversely, mechanisms by which extra-oral conditions exacerbate oral diseases, such as periodontitis, are also beginning to be elucidated. This review discusses the bidirectional interrelationship between oral and systemic diseases based on the oral-gut linkage.

Human Coronary Artery Endothelial Cell Response to Porphyromonas gingivalis W83 in a Collagen Three-Dimensional Culture Model

P. gingivalis has been reported to be an endothelial cell inflammatory response inducer that can lead to endothelial dysfunction processes related to atherosclerosis; however, these studies have been carried out in vitro in cell culture models on two-dimensional (2D) plastic surfaces that do not simulate the natural environment where pathology develops. This work aimed to evaluate the pro-inflammatory response of human coronary artery endothelial cells (HCAECs) to P. gingivalis in a 3D cell culture model compared with a 2D cell culture. HCAECs were cultured for 7 days on type I collagen matrices in both cultures and were stimulated at an MOI of 1 or 100 with live P. gingivalis W83 for 24 h. The expression of the genes COX-2, eNOS, and vWF and the levels of the pro-inflammatory cytokines thromboxane A2 (TXA-2) and prostaglandin I2 (PGI2) were evaluated. P. gingivalis W83 in the 2D cell culture increased IL-8 levels at MOI 100 and decreased MCP-1 levels at both MOI 100 and MOI 1. In contrast, the 3D cell culture induced an increased gene expression of COX-2 at both MOIs and reduced MCP-1 levels at MOI 100, whereas the gene expression of eNOS, vWF, and IL-8 and the levels of TXA2 and PGI2 showed no significant changes. These data suggest that in the collagen 3D culture model, P. gingivalis W83 induces a weak endothelial inflammatory response.

Oral microbiome mediated inflammation, a potential inductor of vascular diseases: a comprehensive review

The dysbiosis of the oral microbiome and vascular translocation of the periodontopathic microorganism to peripheral blood can cause local and systemic extra-oral inflammation. Microorganisms associated with the subgingival biofilm are readily translocated to the peripheral circulation, generating bacteremia and endotoxemia, increasing the inflammation in the vascular endothelium and resulting in endothelial dysfunction. This review aimed to demonstrate how the dysbiosis of the oral microbiome and the translocation of oral pathogen-induced inflammation to peripheral blood may be linked to cardiovascular diseases (CVDs). The dysbiosis of the oral microbiome can regulate blood pressure and activate endothelial dysfunction. Similarly, the passage of periodontal microorganisms into the peripheral circulation and their virulence factors have been associated with a vascular compartment with a great capacity to activate endothelial cells, monocytes, macrophages, and plaquettes and increase interleukin and chemokine secretion, as well as oxidative stress. This inflammatory process is related to atherosclerosis, hypertension, thrombosis, and stroke. Therefore, oral diseases could be involved in CVDs via inflammation. The preclinic and clinical evidence suggests that periodontal disease increases the proinflammatory markers associated with endothelial dysfunction. Likewise, the evidence from clinical studies of periodontal treatment in the long term evidenced the reduction of these markers and improved overall health in patients with CVDs.

Impact of Polymicrobial Infection on Fitness of Streptococcus gordonii In Vivo

Pathogenic microbial ecosystems are often polymicrobial, and interbacterial interactions drive emergent properties of these communities. In the oral cavity, Streptococcus gordonii is a foundational species in the development of plaque biofilms, which can contribute to periodontal disease and, after gaining access to the bloodstream, target remote sites such as heart valves. Here, we used a transposon sequencing (Tn-Seq) library of S. gordonii to identify genes that influence fitness in a murine abscess model, both as a monoinfection and as a coinfection with an oral partner species, Porphyromonas gingivalis. In the context of a monoinfection, conditionally essential genes were widely distributed among functional pathways. Coinfection with P. gingivalis almost completely changed the nature of in vivo gene essentiality. Community-dependent essential (CoDE) genes under the coinfection condition were primarily related to DNA replication, transcription, and translation, indicating that robust growth and replication are required to survive with P. gingivalis in vivo. Interestingly, a group of genes in an operon encoding streptococcal receptor polysaccharide (RPS) were associated with decreased fitness of S. gordonii in a coinfection with P. gingivalis. Individual deletion of two of these genes (SGO_2020 and SGO_2024) resulted in the loss of RPS production by S. gordonii and increased susceptibility to killing by neutrophils. P. gingivalis protected the RPS mutants by inhibiting neutrophil recruitment, degranulation, and neutrophil extracellular trap (NET) formation. These results provide insight into genes and functions that are important for S. gordonii survival in vivo and the nature of polymicrobial synergy with P. gingivalis. Furthermore, we show that RPS-mediated immune protection in S. gordonii is dispensable and detrimental in the presence of a synergistic partner species that can interfere with neutrophil killing mechanisms. IMPORTANCE Bacteria responsible for diseases originating at oral mucosal membranes assemble into polymicrobial communities. However, we know little regarding the fitness determinants of the organisms that initiate community formation. Here, we show that the extracellular polysaccharide of Streptococcus gordonii, while important for streptococcal survival as a monoinfection, is detrimental to survival in the context of a coinfection with Porphyromonas gingivalis. We found that the presence of P. gingivalis compensates for immune protective functions of extracellular polysaccharide, rendering production unnecessary. The results show that fitness determinants of bacteria in communities differ substantially from those of individual species in isolation. Furthermore, constituents of communities can undertake activities that relieve the burden of energetically costly biosynthetic reactions on partner species.

Periodontitis as a promoting factor of T2D: current evidence and mechanisms

Periodontitis is an infectious disease caused by an imbalance between the local microbiota and host immune response. Epidemiologically, periodontitis is closely related to the occurrence, development, and poor prognosis of T2D and is recognized as a potential risk factor for T2D. In recent years, increasing attention has been given to the role of the virulence factors produced by disorders of the subgingival microbiota in the pathological mechanism of T2D, including islet β-cell dysfunction and insulin resistance (IR). However, the related mechanisms have not been well summarized. This review highlights periodontitis-derived virulence factors, reviews how these stimuli directly or indirectly regulate islet β-cell dysfunction. The mechanisms by which IR is induced in insulin-targeting tissues (the liver, visceral adipose tissue, and skeletal muscle) are explained, clarifying the influence of periodontitis on the occurrence and development of T2D. In addition, the positive effects of periodontal therapy on T2D are overviewed. Finally, the limitations and prospects of the current research are discussed. In summary, periodontitis is worthy of attention as a promoting factor of T2D. Understanding on the effect of disseminated periodontitis-derived virulence factors on the T2D-related tissues and cells may provide new treatment options for reducing the risk of T2D associated with periodontitis.

Association between cardiovascular diseases and periodontal disease: more than what meets the eye

Cardiovascular diseases (CVDs) are inflammatory diseases of coronary arteries accompanying atheroma formation that can spawn impairment and, in severe cases, death. CVDs are the leading cause of death in the world. In recent decades, investigators have focused their impact on CVD by periodontal disease (PD). PD is a risk factor that can trigger the formation, maturation, and instability of atheroma in the arteries. Two mechanisms have been proposed to explain this relationship: periodontopathic pathogens explicitly invade the circulation or indirectly increase systemic levels of inflammatory mediators. It has been suggested that improvement in disease state has a positive effect on others. This review summarizes evidence from epidemiological studies as well as researches focusing on potential causation channels to deliver a comprehensive representation of the relationship between PD and CVD.

Role of oral and gut microbiota in childhood obesity

Childhood obesity not only causes damage to children's respiratory, cardiovascular, endocrine, motor, and other systems but also is a significant risk factor for metabolic diseases such as obesity in adulthood, which has become one of the serious public health problems worldwide. The etiology and pathogenesis of obesity are complex. In addition to genetic and lifestyle factors, recent studies have found that the microbes in the digestive tract play a crucial role in the occurrence and development of obesity. Among them, the gut microbiota has been confirmed to be one of the important pathogenic factors of obesity, which can mediate the occurrence and development of obesity by interfering with the balance of host energy metabolism and inducing low-grade chronic inflammation throughout the host. Targeting the gut microbiota to treat obesity through various methods such as fecal microbiota transplantation, dietary intervention, and probiotic supplementation has become a research hotspot in obesity treatment. In addition, the oral microbiota is also considered closely related to the occurrence and development of obesity due to its regulatory effect on the balance of gut microbiota. Exploring the relationship between oral and gut microbiota and childhood obesity elucidates the pathogenesis and treatment concepts of childhood obesity from a new perspective. It may provide new methods for the prevention and treatment of childhood obesity in the future.

Zebrafish as model for studies in dentistry

INTRODUCTION

Over the last years, zebrafish has gained prominence in the biomedical community. It is currently considered one of the best vertebrate animal models for various types of studies, such as toxicology and developmental biology.

OBJECTIVE

The aim of this study was to conduct a literature review on the use of zebrafish in dentistry and whether this animal model could be a viable alternative for performing different types of studies in this area.

METHODS

A literature search was performed using the PubMed, Lilacs, Embase, and Dentistry and Oral Sciences Source. The keywords used as search terms were zebrafish and dentistry. The selection criteria were articles published in English that used zebrafish as an animal model in dentistry, oral health, and craniofacial growth/development.

RESULTS

The electronic search of literature yielded 421 articles. After the analysis of the abstracts, 29 articles were selected for an in-depth analysis and reading of the full text.

CONCLUSIONS

All studies included in this review confirm zebrafish's excellence as an animal model for various types of dentistry studies, as well as assisting and complementing other studies involving mammals.

Fusobacterium nucleatum mediates endothelial damage and increased permeability following single species and polymicrobial infection

BACKGROUND

Numerous lines of evidence link periodontal pathobionts and their virulence factors with endothelial damage. Most research has been conducted using single species infections at the exclusion of other periodontal microorganisms that have been identified in vascular tissue. Here, we assessed endothelial infection with either single or mixed periodontal species infection and examined their effect on endothelial damage and permeability.

METHODS

Cell surface abundance of platelet endothelial cell adhesion molecule-1 (PECAM-1) or endothelial permeability following infection with Porphyromonas gingivalis, Fusobacterium nucleatum subspecies (ssp) nucleatum, ssp polymorphum or Tannerella forsythia as single or mixed species infection was determined by flow cytometry and a fluorescent dextran permeability assay. Zebrafish embryos were infected systemically with either single or mixed species with mortality and disease measured over time.

RESULTS

F. nucleatum ssp nucleatum, ssp polymorphum and P. gingivalis significantly reduced PECAM-1 abundance in single species infection, whereas T. forsythia had no effect. F. nucleatum ssp polymorphum caused considerable mortality and morbidity in a zebrafish systemic infection model. Polymicrobial infection underscored the virulence of F. nucleatum ssp polymorphum in particular with increased endothelial cell death and reduced PECAM-1 abundance in co-infection studies with this organism. When injected systemically into zebrafish in polymicrobial infection, fluorescently labeled bacteria were distributed throughout the vasculature and cardiac region where, in some instances, they co-localized with each other.

CONCLUSIONS

These data provide further evidence on the effects of F. nucleatum on endothelium adhesion molecule abundance and permeability while also highlighting the importance of performing polymicrobial infection to study the molecular mechanisms associated with periodontal pathogen-induced vascular damage.

Association between Periodontitis and Carotid Artery Calcification: A Systematic Review and Meta-Analysis

Recent studies have supported the relationship between periodontitis and carotid artery calcification (CAC), but still uncertain. This systematic review is aimed at evaluating the association between periodontitis and CAC. The search was conducted in four electronic databases: PubMed, EMBASE, Web of Science, and The Cochrane Library, supplemented by checking references of included articles and related review articles. Eligibility assessment and data extraction were conducted independently. The quality assessment and publication bias analysis were performed. The association between periodontitis and CAC was presented in odd ratio (OR) with 95% confidence interval (CI). Additional outcomes included the percentage of alveolar bone loss in CAC versus non-CAC. Twelve studies were included, and 10 were performed quantity analysis. Periodontitis with secure definition (OR = 2.02, 95%CI = 1.18 - 3.45) and insecure definition (OR = 10.78, 95%CI = 4.41 - 26.34) was associated with CAC. And a higher average percentage of alveolar bone loss (weighted mean difference = 10.84%; 95%CI = 6.40 - 15.48) was also observed in CAC patients compared to non-CAC patients. No significant publication bias was found. The results of this systematic review and meta-analysis revealed a significant relationship between periodontitis and CAC.

Mechanisms of vascular damage by systemic dissemination of the oral pathogen Porphyromonas gingivalis

Several studies have shown a clear association between periodontal disease and increased risk of cardiovascular disease. Porphyromonas gingivalis (Pg), a key oral pathogen, and its cell surface-expressed gingipains, induce oedema in a zebrafish larvae infection model although the mechanism of these vascular effects is unknown. Here, we aimed to determine whether Pg-induced vascular damage is mediated by gingipains. In vitro, human endothelial cells from different vascular beds were invaded by wild-type (W83) but not gingipain-deficient (ΔK/R-ab) Pg. W83 infection resulted in increased endothelial permeability as well as decreased cell surface abundance of endothelial adhesion molecules PECAM-1 and VE-cadherin compared to infection with ΔK/R-ab. In agreement, when transgenic zebrafish larvae expressing fluorescently labelled PECAM-1 or VE-cadherin were systemically infected with W83 or ΔK/R-ab, a significant reduction in adhesion molecule fluorescence was observed specifically in endothelium proximal to W83 bacteria through a gingipain-dependent mechanism. Furthermore, this was associated with increased vascular permeability in vivo when assessed by dextran leakage microangiography. These data are the first to show that Pg directly mediates vascular damage in vivo by degrading PECAM-1 and VE-cadherin. Our data provide a molecular mechanism by which Pg might contribute to cardiovascular disease.

Influence of periodontal treatment on blood microbiotas: a clinical trial

Objective

To investigate the effects of periodontal treatment on the abundance and diversity of blood microbiota.

Methods and Materials

Twenty-seven periodontitis patients were randomly allocated to a control group (A) and two test groups (B1 and B2). Group A patients received full-mouth scaling and root planing (SRP), group B1 patients received subgingival glycine air polishing (GAP) right after SRP, and group B2 patients received subgingival glycine air polishing right before SRP. Peripheral blood samples were obtained at the baseline, the day after periodontal treatment, and 6 weeks after treatment and evaluated using nested polymerase chain reaction and 16SrRNA Gene Sequencing (Miseq platform).

Results

All participants exhibited significant improvements in the clinical parameters evaluated at the 6-week follow-up visit compared to the values at the baseline, but no significant differences were observed between the three groups. The total bacterial count was lowest in group B2. The bacterial species diversity (α-diversity) in group B1 was significantly higher (Chao-1 index, P = 0.03) and Porphyromonas and Pantoea were the dominant genera (linear discriminant analysis (LDA > 2)) in this group the day after treatment compared to the baseline. No significant difference was detected in the relative abundance and α-diversity of blood microbiota between the baseline and 6 weeks after treatment.

Conclusion

Local periodontal treatment merely disrupts the stability of blood microbiota in the short term. Periodontitis treatment using full-mouth SRP followed by adjunctive GAP is a promising approach to reduce the introduction of bacteria into the bloodstream during the procedure.

Periodontal diseases and depression: A pre-clinical in vivo study

AIM

To analyse, through a pre-clinical in vivo model, the possible mechanisms linking depression and periodontitis at behavioural, microbiological and molecular levels.

MATERIALS AND METHODS

Periodontitis (P) was induced in Wistar:Han rats (oral gavages with Porphyromonas gingivalis and Fusobacterium nucleatum) during 12 weeks, followed by a 3-week period of Chronic Mild Stress (CMS) induction. Four groups (n = 12 rats/group) were obtained: periodontitis and CMS (P+CMS+); periodontitis without CMS; CMS without periodontitis; and control. Periodontal clinical variables, alveolar bone levels (ABL), depressive-like behaviour, microbial counts and expression of inflammatory mediators in plasma and brain frontal cortex (FC), were measured. ANOVA tests were applied.

RESULTS

The highest values for ABL occurred in the P+CMS+ group, which also presented the highest expression of pro-inflammatory mediators (TNF-α, IL-1β and NF-kB) in frontal cortex, related to the lipoprotein APOA1-mediated transport of bacterial lipopolysaccharide to the brain and the detection of F. nucleatum in the brain parenchyma. A dysregulation of the hypothalamic-pituitary-adrenal stress axis, reflected by the increase in plasma corticosterone and glucocorticoid receptor levels in FC, was also found in this group.

CONCLUSIONS

Neuroinflammation induced by F. nucleatum (through a leaky mouth) might act as the linking mechanism between periodontal diseases and depression.

Association Between Periodontal Disease and Atherosclerotic Cardiovascular Diseases: Revisited

Atherosclerotic cardiovascular disease (ACVD) is an inflammatory disease of the coronary arteries associated with atheroma formation, which can cause disability and often death. Periodontitis is ranked as the sixth most prevalent disease affecting humans affecting 740 million people worldwide. In the last few decades, researchers have focused on the effect of periodontal disease (PD) on cardiovascular disease. The aim of this review was to investigate the association between these two diseases. PD is a potential risk factor that may initiate the development, maturation, and instability of atheroma in the arteries. Two mechanisms were proposed to explain such association, either periodontal pathogens directly invade bloodstream or indirectly by increasing systemic level of inflammatory mediators. Interestingly, it has been suggested that improvement in the condition of one disease positively impact the condition of the other one. Highlighting the association between these two diseases, the importance of early diagnosis and treatment of PD and its impact on cardiovascular status may be of great value in reducing the complications associated with ACVDs. Further in vitro and in vivo studies with longer follow up are necessary to confirm the causal relationship between PD and ACVDs.

Porphyromonas gingivalis Outer Membrane Vesicles Increase Vascular Permeability

Periodontitis is increasingly associated with increased risk of cardiovascular and other systemic diseases. The Gram-negative anaerobe, Porphyromonas gingivalis, is a key periodontal pathogen, and several lines of evidence link the presence of this bacterium in the circulation with vascular disease. The outer membrane vesicles (OMVs) produced by P. gingivalis have been shown to play a role in periodontitis, although, to date, little is known about their interaction with the vasculature; therefore, this study assessed the effects of P. gingivalis OMVs on the endothelium. OMVs were isolated from wild-type strain W83 and the gingipain-deficient strain ΔK/R-ab. Immunoblotting along with cryo-EM showed gingipain expression in W83 but not ΔK/R-ab-derived OMVs, where gingipains were localized to the cell wall surface. Confluent endothelial cell monolayers infected with either W83 or W83-derived OMV displayed significantly increased dextran permeability over those infected with ΔK/R-ab or its OMV. Moreover, W83-derived OMVs induced significantly more vascular disease in a zebrafish larvae systemic infection model over 72 h compared to those injected with gingipain-deficient OMVs or controls. In line with these data, human microvascular endothelial cells (HMEC-1) displayed an OMV-associated, gingipain-dependent decrease in cell surface levels of the intercellular adhesion molecule PECAM-1 (CD31) when examined by flow cytometry. These data show, for the first time, that OMVs from P. gingivalis mediate increased vascular permeability, leading to a diseased phenotype both in vitro and in vivo. Moreover, these data strongly implicate gingipains present on the OMV surface in mediating these vascular events, most likely via a mechanism that involves proteolytic cleavage of endothelial cell-cell adhesins such as PECAM-1. These data provide important evidence for the role of bacterial-derived OMVs in mediating systemic disease.

Clinical and microbiological effects of non-surgical periodontal treatment in individuals with rheumatoid arthritis: a controlled clinical trial

The effect of periodontal treatment on clinical, microbiological and serological parameters of patients with rheumatoid arthritis (RA) are scarce and controversial. The aim of this study was to investigate the influence of non-surgical periodontal treatment on clinical periodontal status, subgingival bacterial levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola and RA activity through a controlled clinical trial on individuals with RA and periodontitis (PE). From a convenience sample, 107 individuals were considered eligible and consecutively allocated in four groups: (1) individuals without PE and RA (- PE-RA, n = 30); (2) individuals without PE and with RA (- PE + RA, n = 23); (3) individuals with PE and RA (+ PE + RA, n = 24); and (4) individuals with PE and without RA (+ PE-RA, n = 30). Full-mouth periodontal clinical examinations, microbiological analysis and Disease Activity Score (DAS-28) evaluations were performed at baseline (T1) and 45 days after non-surgical periodontal treatment (T2). At T1, individuals + PE + RA showed greater severity of PE than + PE-RA individuals. At T2, significant reductions were observed in all periodontal clinical parameters in both groups (p < 0.001) with a significant reduction in DAS-28 in + PE + RA (p = 0.011). Individuals + PE-RA and + PE-RA showed significant reductions for all bacteria (p < 0.001). Additionally, P. gingivalis demonstrated an expressively significant reduction in + PE + RA (p < 0.001). Non-surgical periodontal treatment was effective on improving the clinical periodontal condition, improving the RA clinical status and reducing the presence of periodontal pathogens. Brazilian Registry of Clinical Trials (ReBEC) protocol #RBR-8g2bc8 ( https://www.ensaiosclinicos.gov.br/rg/RBR-8g2bc8/ ).

Evaluation of Antibiotic Resistance Pattern in Dental Bacteremia Detected by Multiplex PCR Technique

The aim of this study was to detect oral bacteremia and offer the antibiotic resistance patterns. Bacterial resistance pattern was evaluated in 50 patients. A spectrophotometer device equipped with UV and electrophoresis of the extracted samples on agarose gel for antibiogram test were used. PCR test 15 minutes after tooth extraction showed that bacterial strains were extracted from 16 patients. Lactobacillus, Enterococcus faecalis (E. faecalis), Streptococcus sanguinis (S. sanguinis), Streptococcus salivarius (S. salivarius), and Streptococcus mutans (S. mutans) were extracted from 5, 4, 4, 4, and 6 patients. 100% of Lactobacillus, E. faecalis, S. sanguinis, S. salivarius, and S. mutans were sensitive to tigecycline. Most of the Lactobacillus antibiotic resistance was against tetracycline and ciprofloxacin. Antibiotic resistance in S. salivarius was observed in 75% of the cases against piperacillin-tazobactam, ciprofloxacin, and cefotaxime, while in S. mutans was 84% of the cases against ceftriaxone. The results of the current study showed that tooth extraction causes bacteremia before, during, and after tooth extraction. Generally, the highest antibiotic resistance occurred against tetracycline, ciprofloxacin, and ampicillin-sulbactam. In most cases, the bacteria showed partial resistance to these antibiotics; however, tigecycline showed 100% efficacy on all types of bacteria. Streptococcus strains (salivarius, mutans, and sanguinis) were sensitive to most of the antibiotics while antibiotic sensitivity was less evident in Lactobacillus and E. faecalis. Antibiotic resistance has become a critical issue, since it leads to treatment failure when there is a need for antibiotic therapy.

Mechanisms underlying the association between periodontitis and atherosclerotic disease

Atherosclerosis is central to the pathology of cardiovascular diseases, a group of diseases in which arteries become occluded with atheromas that may rupture, leading to different cardiovascular events, such as myocardial infarction or ischemic stroke. There is a large body of epidemiologic and animal model evidence associating periodontitis with atherosclerotic disease, and many potential mechanisms linking these diseases have been elucidated. This chapter will update knowledge on these mechanisms, which generally fall into 2 categories: microbial invasion and infection of atheromas; and inflammatory and immunologic. With respect to the invasion and infection of atheromas, it is well established that organisms from the subgingival biofilm can enter the circulation and lodge in most distant tissues. Bacteremias resulting from oral interventions, and even oral hygiene activities, are well documented. More recently, indirect routes of entry of oral organisms (via phagocytes or dendritic cells) have been described for many oral organisms, into many tissues. Such organisms include the periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Tannerella forsythia, and Fusobacterium nucleatum. Intracellular survival of these organisms with dissemination to distant sites (The Trojan Horse approach) has been described. Their relative contribution to atheroma formation and progression has been studied mainly in experimental research, with results demonstrating that these organisms can invade endothelial cells and phagocytic cells within the atheroma, leading to pathogenic changes and progression of the atheroma lesion. The second category of mechanisms potentially linking periodontitis to atherosclerosis includes the dumping of inflammatory mediators originating from periodontal lesions into the systemic circulation. These inflammatory mediators, such as C-reactive protein, matrix metalloproteinases, fibrinogen, and other hemostatic factors, would further accelerate atheroma formation and progression, mainly through oxidative stress and inflammatory dysfunction. Moreover, direct effects on lipid oxidation have also been described. In summary, the evidence supports the concept that periodontitis enhances the levels of systemic mediators of inflammation that are risk factors for atherosclerotic diseases.

Periodontal disease and adverse pregnancy outcomes

Periodontal diseases are considered not only to affect tooth-supporting tissues but also to have a cause-and-effect relationship with various systemic diseases and conditions, such as adverse pregnancy outcomes. Mechanistic studies provide strong evidence that periodontal pathogens can translocate from infected periodontium to the feto-placental unit and initiate a metastatic infection. However, the extent and mechanisms by which metastatic inflammation and injury contribute to adverse pregnancy outcomes still remain unclear. The presence of oral bacteria in the placenta of women with term gestation further complicates our understanding of the biology behind the role of periodontal pathogens in pregnancy outcomes. Epidemiological studies demonstrate many methodological inconsistencies and flaws that render comparisons difficult and conclusions insecure. Therefore, despite the fact that a number of prospective studies show a positive association between periodontal diseases and various adverse pregnancy outcomes, the evidence behind it is still weak. Future well-designed explanatory studies are necessary to verify this relationship and, if present, determine its magnitude. The majority of high-quality randomized controlled trials reveal that nonsurgical periodontal therapy during the second trimester of gestation does not improve pregnancy outcomes. From a biological standpoint, this can be partially explained by the fact that therapy rendered at the fourth to sixth months of pregnancy is too late to prevent placental colonization by periodontal pathogens and consequently incapable of affecting pathogen-induced injury at the feto-placental unit. Thus, interventions during the preconception period may be more meaningful. With the increase in our understanding on the potential association between periodontal disease and adverse pregnancy outcomes, it is clear that dental practitioners should provide periodontal treatment to pregnant women that is safe for both the mother and the unborn child. Although there is not enough evidence that the anti-infective therapy alters pregnancy outcomes, it improves health-promoting behavior and periodontal condition, which in turn advance general health and risk factor control.

Oral health in patients with chronic kidney disease

Objective: In the available literature data, there is not much information about problems of patients with end stage kidney disease in relation to oral health. Our objective was to show the importance of oral diseases for patients on hemodialysis. Data sources: In this review article, the sources of data are review articles and scientific articles in the English language published in MEDLINE database. The choice of studies was based on keywords: Chronic kidney disease, Hemodialysis, Oral health, Periodontal diseases. Results: It is assumed that almost 90% patients with chronic kidney disease manifest some symptoms of oral disease. Therefore, it is important to determine the impact of periodontal disease on the progression of kidney failure in these individuals, to evaluate inflammatory parameters in this patient population, to assess the degree of bone loss and periodontal disease index, to determine the presence of bacterial strains, paradontopathy of gingival fluid and antibody titers, to examine correlations of proinflammatory cytokines in the gingival sulcus and serum, as well as to determine the relationship between periodontal tissue and inflammatory mediators. Periodontal diseases can increase the possibility of developing chronic kidney disease by 1.5 to 2 times. These oral diseases include gingival hyperplasia, periodontitis, xerostomia, unpleasant breath, changes in the oral mucosa, malignancies, oral infections, dental abnormalities and bone lesions. Conclusion: This requires serious cooperation between nephrologists and dentists to make proper communication possible, in order to provide quality dental care for this growing patient population in accordance with new treatment strategies.

Pathogenomics of Emerging Campylobacter Species

Campylobacter is among the four main causes of gastroenteritis worldwide and has increased in both developed and developing countries over the last 10 years. The vast majority of reported Campylobacter infections are caused by Campylobacter jejuni and, to a lesser extent, C. coli; however, the increasing recognition of other emerging Campylobacter pathogens is urgently demanding a better understanding of how these underestimated species cause disease, transmit, and evolve. In parallel to the enhanced clinical awareness of campylobacteriosis due to improved diagnostic protocols, the application of high-throughput sequencing has increased the number of whole-genome sequences available to dozens of strains of many emerging campylobacters. This has allowed for comprehensive comparative pathogenomic analyses for several species, such as C. fetus and C. concisus These studies have started to reveal the evolutionary forces shaping their genomes and have brought to light many genomic features related to pathogenicity in these neglected species, promoting the development of new tools and approaches relevant for clinical microbiology. Despite the need for additional characterization of genomic diversity in emerging campylobacters, the increasing body of literature describing pathogenomic studies on these species deserves to be discussed from an integrative perspective. This review compiles the current knowledge and highlights future work toward deepening our understanding about genome dynamics and the mechanisms governing the evolution of pathogenicity in emerging Campylobacter species, which is urgently needed to develop strategies to prevent or control the spread of these pathogens.

Multiplex polymerase chain reaction for detection of bacteremia during dental extraction

AIM

Incidence of transient bacteremia following dental extractions ranges 30%-70% among adults and 58%-100% in children. This study aims to assess the multiplex polymerase chain reaction (PCR) technique in detection of transient bacteremia during dental extraction.

METHODS

Twenty volunteers for dental extraction entered the study. Blood samples were taken at baseline and 30 seconds and 15 minutes after extraction. Five types of bacteria were selected, namely Streptococcus mutans, S. salivarius, S. sanguinis, Enterococcus faecalis and Lactobacillus. Blood samples were evaluated by microbial culture and multiplex PCR.

RESULTS

Blood culture showed rates of 0%, 80% and 25% for bacteremia before, during and after dental extraction, respectively. A significant difference was observed between baseline and during extraction. Using PCR, bacteremia was deemed 20%, 100% and 30% before, during and after extraction, respectively, and a significant difference was witnessed between the baseline and during extraction. The highest incidence was at the 30-second mark after extraction, and the most prevalent type of bacteria was S. mutans.

CONCLUSIONS

Multiplex PCR can be used to determine bacterial diversity with high accuracy during occurrence of bacteremia. Therefore, in cases where positive blood cultures only indicate the presence of one species, we recommend the use of this method to detect more diverse bacteria types.

Subgingival microbiome in Chinese patients with generalized aggressive periodontitis compared to healthy controls

OBJECTIVE

The aim of the study was to profile the subgingival microbiome of Chinese adults with generalized aggressive periodontitis (GAgP) using human oral microbe identification microarray (HOMIM), and to compare the results with matched periodontal healthy controls.

DESIGN

15 subjects with GAgP and 15 age- and gender- matched periodontal healthy controls were included. Subgingival plaque samples were collected from the deepest pockets of patients with GAgP and matched sites in controls and then analyzed by 16S rRNA-based microarrays. Student's paired t-test was used to compare clinical parameters and mean number of bacterial taxa detected between the two groups. Fisher's exact probability test and Wilcoxon Rank Sum were used to compare bacterial species between all samples. A multiple linear regression model was used for correlations among age, gender and bacterial with clinical parameters.

RESULTS

From a total sum of 379 strains tested, 171 bacterial strains were detected from subgingival plaques of the GAgP patients, more than the 157 strains detected in control group. Mean number of subgingival bacterial taxa detected in GAgP group was 68 (SD = 21.06) while in control group was 45 (SD = 21.60). 47 bacterial taxa were detected more frequently in GAgP group while 12 taxa were more prevalent in control group. The significantly more prevalent and abundant taxa of bacteria in GAgP group included Filifactor alocis, Desulfobulbus sp., Fretibacterium sp., Porphyromonas gingivalis, Tannerella forsythia, Porphyromon as endodontalis, Peptostreptococcaceae spp., Parvimonas micra, Eubacterium nodatum and Eubacterium saphenum. Meanwhile the more abundant taxa in control group were Streptococcus spp. and Pseudomonas aeruginosa.

CONCLUSIONS

There are more taxa of bacteria in subgingival plaques of Chinese patients with GAgP than in healthy controls. F. alocis, Desulfobulbus sp., Fretibacterium sp., P. gingivalis and T. forsythia are strongly associated with GAgP. High-throughout microbiological results may help dentists have a better understanding of subgingival microbiome of GAgP.

Detection and quantification of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in bacteremia induced by interdental brushing in periodontally healthy and periodontitis patients

OBJECTIVE

This study was aimed to compare the presence and amounts of bacteremia induced by interdental brushing in periodontally healthy (H) and periodontitis (P) individuals using culture based (direct culture [DC]) and molecular based techniques (real-time quantitative polymerase chain reaction [qPCR]) in a cross-sectional study model.

MATERIALS AND METHODS

After a full mouth periodontal evaluation, blood samples were taken before and 1 min after professionally-administered interdental brushing. These samples were analyzed by DC and qPCR, targeting Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Subgingival samples were also collected and analyzed. Student t-test, chi-squar tests and correlations were used for analyzing the data.

RESULTS

Thirty individuals per group were included. P. gingivalis and A. actinomycetemcomitans were detected with qPCR methods, but not with DC. At baseline, bacteremia was observed in 5 P patients (16.7%) and in 2 H individuals (6.6%) (p = 0.421). After interdental brushing, bacteremia was only observed in 2 P patients (6.6%) (p = 0.901). A positive correlation between subgingival and blood levels of A. actinomycetemcomitans was observed (r = 0.3; p = 0.013).

CONCLUSION

Bacteremia related to A. actinomycetemcomitans and P. gingivalis did not significantly increase after a single session of use of interdental brushes.

Defining the gut microbiota in individuals with periodontal diseases: an exploratory study

Background: This exploratory study aimed to characterize the gut microbiome of individuals with different periodontal conditions, and correlate it with periodontal inflammation and tissue destruction. Methods: Stool samples were obtained from individuals presenting periodontal health (PH = 7), gingivitis (G = 14) and chronic periodontitis (CP = 23). The intestinal microbiome composition was determined by Illumina MiSeq sequencing. Results: A lower alpha-diversity in the gut microbiome of individuals with CP was observed, although no significant difference among groups was found (p > 0.01). Firmicutes, Proteobacteria, Verrucomicrobia and Euryarchaeota were increased, whereas Bacteroidetes were decreased in abundance in patients with periodontitis compared to PH. Prevotella (genus), Comamonadaceae (family) and Lactobacillales (order) were detected in higher numbers in G, while Bacteroidales (order) was predominant in PH (p < 0.01). Significant correlations (rho = 0.337-0.468, p < 0.01) were found between OTUs representative of periodontal pathogens and attachment loss. Mogibacteriaceae, Ruminococcaceae and Prevotella were able to discriminate individuals with periodontal diseases from PH (overall accuracy = 84%). Oral taxa were detected in high numbers in all stool samples. Conclusions: Individuals with periodontal diseases present a less diverse gut microbiome consistent with other systemic inflammatory diseases. High numbers of oral taxa related to periodontal destruction and inflammation were detected in the gut microbiome of individuals regardless of periodontal status.

A meta-analysis of emotional disorders as possible risk factors for chronic periodontitis

The aim of the present meta-analysis was to evaluate scientific evidence on the association between emotional disorder (depression and anxiety) and chronic periodontitis. An overall electronic literature search in PubMed, ISI Web of Science, Cochrane Library, and China National Knowledge Infrastructure was undertaken up to November 2017. Newcastle-Ottawa scale was applied to ascertain the validity of each eligible study. Stata statistical software was used to perform meta-analysis. The strength of the association between periodontitis and emotional disorder was measured by odds ratios (ORs) with their 95% confidence intervals (95% CIs). Subgroup analysis and sensitivity analysis were performed. Publication bias was assessed through funnel plots and Begger's test. A total of 14 eligible articles were included in the meta-analysis, 6 of them were focused exclusively on depression, whereas 8 studies investigated both depression and anxiety. There was significant association between emotional disorder and chronic periodontitis (OR = 1.54, 95% CI = 1.27-1.86). Sensitivity analyses confirmed the stability of the present results. No evidence of asymmetry was observed in Begger's test. This meta-analysis demonstrates significant association between emotional disorder (including anxiety and depression) and chronic periodontitis. Nevertheless, the result should be interpreted with caution because of the potential bias and confounding in the included studies.

Bacteremia after supragingival scaling and dental extraction: Culture and molecular analyses

OBJECTIVE

To study the incidence and magnitude of bacteremia after dental extraction and supragingival scaling.

SUBJECTS AND METHODS

Blood samples were taken before and 5 and 30 min after dental extraction and supragingival scaling from individuals at high (n = 44) or negligible risk (n = 51) for infective endocarditis. The former received prophylactic antibiotic therapy. Samples were subjected to aerobic and anaerobic culture and quantitative real-time polymerase chain reaction to determine the incidence of bacteremia and total bacterial levels.

RESULTS

Patients who did not receive prophylactic antibiotic therapy had a higher incidence of positive blood cultures (30% 5 min after extraction) than patients who received prophylactic antibiotic therapy (0% 5 min after extraction; p < .01). Molecular analysis did not reveal significant differences in the incidence or magnitude of bacteremia between the two patient groups either 5 or 30 min after each of the procedures evaluated. Extraction was associated with higher incidence of bacteremia than supragingival scaling by blood culture (p = .03) and molecular analysis (p = .05).

CONCLUSIONS

Molecular methods revealed that dental extraction and supragingival scaling were associated with similar incidence of bacteremia in groups receiving or not prophylactic antibiotic therapy. However, blood culture revealed that antibiotic therapy reduced viable cultivable bacteria in the bloodstream in the extraction group.

Zebrafish as a new model to study effects of periodontal pathogens on cardiovascular diseases

Porphyromonas gingivalis (Pg) is a keystone pathogen in the aetiology of chronic periodontitis. However, recent evidence suggests that the bacterium is also able to enter the bloodstream, interact with host cells and tissues, and ultimately contribute to the pathogenesis of cardiovascular disease (CVD). Here we established a novel zebrafish larvae systemic infection model showing that Pg rapidly adheres to and penetrates the zebrafish vascular endothelium causing a dose- and time-dependent mortality with associated development of pericardial oedemas and cardiac damage. The in vivo model was then used to probe the role of Pg expressed gingipain proteases using systemically delivered gingipain-deficient Pg mutants, which displayed significantly reduced zebrafish morbidity and mortality compared to wild-type bacteria. In addition, we used the zebrafish model to show efficacy of a gingipain inhibitor (KYT) on Pg-mediated systemic disease, suggesting its potential use therapeutically. Our data reveal the first real-time in vivo evidence of intracellular Pg within the endothelium of an infection model and establishes that gingipains are crucially linked to systemic disease and potentially contribute to CVD.

The effects of periodontal treatment on pregnancy outcomes

BACKGROUND

Preterm infants are at greater risk than term infants for physical and developmental disorders. Morbidity and mortality increases as gestational age at delivery decreases. Observational studies indicate an association between poor periodontal health and risk for preterm birth or low birthweight, making periodontitis a potentially modifiable risk factor for prematurity.

AIM

To identify randomized controlled trials (RCTs) published between January 2011 and July 2012 and discuss all published RCTs testing whether periodontal therapy reduces rates of preterm birth and low birthweight.

METHODS

Search of databases including PubMed, ISI Web of Science and Cochrane Library.

RESULTS

The single RCT identified showed no significant effect of periodontal treatment on birth outcomes.

DISCUSSION

All published trials included non-surgical periodontal therapy; only two included systemic antimicrobials as part of test therapy. The trials varied substantially in terms of sample size, obstetric histories of subjects, study preterm birth rates and the periodontal treatment response. The largest trials--also judged to be high-quality and at low risk of bias--have yielded consistent results, and indicate that treatment does not alter rates of adverse pregnancy outcomes.

CONCLUSION

Non-surgical periodontal therapy, scaling and root planing, does not improve birth outcomes in pregnant women with periodontitis.

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 effects of periodontal treatment on pregnancy outcomes

BACKGROUND

Preterm infants are at greater risk than term infants for physical and developmental disorders. Morbidity and mortality increases as gestational age at delivery decreases. Observational studies indicate an association between poor periodontal health and risk for preterm birth or low birthweight, making periodontitis a potentially modifiable risk factor for prematurity.

AIM

To identify randomized controlled trials (RCTs) published between January 2011 and July 2012 and discuss all published RCTs testing whether periodontal therapy reduces rates of preterm birth and low birthweight.

METHODS

Search of databases including PubMed, ISI Web of Science and Cochrane Library.

RESULTS

The single RCT identified showed no significant effect of periodontal treatment on birth outcomes.

DISCUSSION

All published trials included non-surgical periodontal therapy; only two included systemic antimicrobials as part of test therapy. The trials varied substantially in terms of sample size, obstetric histories of subjects, study preterm birth rates and the periodontal treatment response. The largest trials - also judged to be high-quality and at low risk of bias - have yielded consistent results, and indicate that treatment does not alter rates of adverse pregnancy outcomes.

CONCLUSION

Non-surgical periodontal therapy, scaling and root planing, does not improve birth outcomes in pregnant women with periodontitis.

Association between maternal periodontitis and preterm and/or low birth weight infants in normal pregnancies

OBJECTIVE

To relate the periodontal condition with the presence of periodontal bacteria in pregnant that had babies with preterm delivery or/and low weight at birth (PTLBW).

METHODS

We recruited 134 pregnant women without systemic diseases attending at the Gynaecology and Obstetrics Room, from Maternal Provincial Hospital, Córdoba, Argentine. Pregnant were grouped according to the International Classification for a System of Periodontal Disease. A sample from periodontal pocket was extracted to identify Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf) Prevotella intermedia (Pi) and Agreggatibacter actinomycemcomitans (Aa).

RESULTS

We identified 7 (5%) cases of children born underweight or preterm of mothers diagnosed with Gingivitis, 6 (4%) in Mild Periodontitis and 4 (3%) in Moderate Periodontitis. We estimated that when Pi and/or Aa were not detected in the periodontal pockets of mothers, the infants had more than 129% chance of having normal birth weights (OR 3.47 for Pi and OR and 2.29 for Aa). The average age of the mothers who has PTLBW was 21 ± 3.5. The age showed an association with PTLBW (p < 0.0008).

CONCLUSIONS

The presences of periodontal pathogens in periodontal pockets from pregnant with different periodontal status would associate with PTLBW infants when the mothers are young, and the normal term and normal birth weight infant are associated with the absence of periodonto bacteria like Pi and Aa.

Porphyromonas gingivalis lipopolysaccharide upregulates insulin secretion from pancreatic β cell line MIN6

BACKGROUND

A close association between periodontitis and diabetes has been demonstrated in human cross-sectional studies, but an exact relationship between periodontitis and prediabetes has not been established. Previous studies using animal model systems consistently have shown that hyperinsulinemia occurs in animals with periodontitis compared to animals with healthy periodontium (while maintaining normoglycemia). Because bacterial lipopolysaccharide (LPS) plays an important role in the pathogenesis of periodontitis, we hypothesized that LPS may stimulate insulin secretion through a direct effect on β cell function. To test this hypothesis, pancreatic β cell line MIN6 cells were used to determine the effect of Porphyromonas gingivalis (Pg) LPS on insulin secretion. Furthermore, expression of genes altered by Pg LPS in innate immunity and insulin-signaling pathways was determined.

METHODS

MIN6 cells were grown in medium with glucose concentration of normoglycemia (5.5 mM). Pg LPS was added to each well at final concentrations of 50, 200, and 500 ng/mL. Insulin secretion was measured using enzyme-linked immunosorbent assay. Gene expression levels altered by Pg LPS were determined by polymerase chain reaction (PCR) array for mouse innate and adaptive immunity response and mouse insulin-signaling pathways, and results were confirmed for specific genes of interest by quantitative PCR.

RESULTS

Pg LPS stimulated insulin secretion in the normoglycemic condition by ≈1.5- to 3.0-fold depending on the concentration of LPS. Pg LPS treatment altered the expression of several genes involved in innate and adaptive immune response and insulin-signaling pathway. Pg LPS upregulated the expression of the immune response-related genes cluster of differentiation 8a (Cd8a), Cd14, and intercellular adhesion molecule-1 (Icam1) by about two-fold. LPS also increased the expression of two insulin signaling-related genes, glucose-6-phosphatase catalytic subunit (G6pc) and insulin-like 3 (Insl3), by three- to four-fold.

CONCLUSIONS

We have demonstrated for the first time that Pg LPS stimulates insulin secretion by pancreatic β cell line MIN cells. Pg LPS may have significant implications on the development of β cell compensation and insulin resistance in prediabetes in individuals with periodontitis.

Infectious burden and atherosclerosis: A clinical issue

Atherosclerotic cardiovascular diseases, chronic inflammatory diseases of multifactorial etiology, are the leading cause of death worldwide. In the last decade, more infectious agents, labeled as “infectious burden”, rather than any single pathogen, have been showed to contribute to the development of atherosclerosis through different mechanisms. Some microorganisms, such as Chlamydia pneumoniae (C. pneumoniae), human cytomegalovirus, etc. may act directly on the arterial wall contributing to endothelial dysfunction, foam cell formation, smooth muscle cell proliferation, platelet aggregation as well as cytokine, reactive oxygen specie, growth factor, and cellular adhesion molecule production. Others, such as Helicobacter pylori (H. pylori), influenza virus, etc. may induce a systemic inflammation which in turn may damage the vascular wall (e.g., by cytokines and proteases). Moreover, another indirect mechanism by which some infectious agents (such as H. pylori, C. pneumoniae, periodontal pathogens, etc.) may play a role in the pathogenesis of atherosclerosis is molecular mimicry. Given the complexity of the mechanisms by which each microorganism may contribute to atherosclerosis, defining the interplay of more infectious agents is far more difficult because the pro-atherogenic effect of each pathogen might be amplified. Clearly, continued research and a greater awareness will be helpful to improve our knowledge on the complex interaction between the infectious burden and atherosclerosis.

Dissemination of periodontal pathogens in the bloodstream after periodontal procedures: a systematic review

BACKGROUND

To date, there is no compilation of evidence-based information associating bacteremia and periodontal procedures. This systematic review aims to assess magnitude, duration, prevalence and nature of bacteremia caused by periodontal procedures.

STUDY DESIGN

Systematic Review.

TYPES OF STUDIES REVIEWED

MEDLINE, EMBASE and LILACS databases were searched in duplicate through August, 2013 without language restriction. Observational studies were included if blood samples were collected before, during or after periodontal procedures of patients with periodontitis. The methodological quality was assessed in duplicate using the modified Newcastle-Ottawa scale (NOS).

RESULTS

Search strategy identified 509 potentially eligible articles and nine were included. Only four studies demonstrated high methodological quality, whereas five were of medium or low methodological quality. The study characteristics were considered too heterogeneous to conduct a meta-analysis. Among 219 analyzed patients, 106 (49.4%) had positive bacteremia. More frequent bacteria were S. viridans, A. actinomycetemcomitans P. gingivalis, M. micros and species Streptococcus and Actinomyces, although identification methods of microbiologic assays were different among studies.

CLINICAL IMPLICATIONS

Although half of the patients presented positive bacteremia after periodontal procedures, accurate results regarding the magnitude, duration and nature of bacteremia could not be confidentially assessed.

Porphyromonas gingivalis promotes neointimal formation after arterial injury through toll-like receptor 2 signaling

We previously demonstrated that Porphyromonas gingivalis infection induces neointimal hyperplasia with an increase in monocyte chemoattractant protein (MCP)-1 after arterial injury in wild-type mice. Toll-like receptor (TLR) 2 is a key receptor for the virulence factors of P. gingivalis. The aim of this study was to assess whether TLR2 plays a role in periodontopathic bacteria-induced neointimal formation after an arterial injury. Wild-type and TLR2-deficient mice were used in this study. The femoral arteries were injured, and P. gingivalis or vehicle was injected subcutaneously once per week. Fourteen days after arterial injury, the murine femoral arteries were obtained for histopathologic and immunohistochemical analyses. The immunoglobulin-G levels of the P. gingivalis-infected groups were significantly increased in comparison with the level in the corresponding noninfected groups in both wild-type and TLR2-deficient mice. TLR2 deficiency negated the P. gingivalis-induced neointimal formation in comparison with the wild-type mice, and reduced the number of positive monocyte chemoattractant protein-1 cells in the neointimal area. These findings demonstrate that P. gingivalis infection can promote neointimal formation after an arterial injury through TLR2 signaling.