Serum lipopolysaccharide neutralizing capacity in ischemic stroke

Anti-Porphyromonas gingivalis Antibody Levels in Patients With Stroke and Atrial Fibrillation: A Systematic Review and Meta-Analysis

OBJECTIVES

Atrial fibrillation (AF) and stroke are two highly related conditions, with periodontitis and periodontal pathogens, such as Porphyromonas gingivalis (Pg), appearing to be the most prominent common risk factors. In this study, we evaluated studies assessing Pg infection via serum/plasma anti-Pg antibodies in patients with AF and/or stroke.

MATERIAL AND METHODS

Online databases (PubMed, Scopus, Embase, and the Web of Science) were screened for studies showing the association between anti-Pg antibodies with stroke and/or AF. Relevant data were extracted, and a subsequent random-effects meta-analysis was performed to calculate the pooled odds ratio (OR) or standardized mean difference (SMD) and 95% confidence intervals (CIs) for Pg seropositivity or anti-Pg antibody levels in stroke patients compared to controls.

RESULTS

Sixteen studies were included in the systematic review. Based on the meta-analysis performed, there was no significant difference in Pg IgA and IgG levels between patients with stroke and controls (IgA: SMD 0.11, 95% CI -0.02 to 0.25, p = 0.1; IgG: SMD -0.12, 95% CI -1.24 to 0.99, p = 0.83). Similarly, no difference was observed between these groups in terms of Pg IgA and IgG seropositivity (IgA: OR 1.63, 95% CI 1.06-2.50, p = 0.026; IgG: OR 2.30, 95% CI 1.39-3.78, p < 0.001). Subsequently, we reviewed the results of six articles investigating serum or plasma IgG antibodies against Pg in patients with AF. Our results revealed a strict association between Pg infection and AF, with AF patients exhibiting either higher anti-Pg antibody levels or a higher prevalence of positive serum Pg antibodies.

CONCLUSIONS

Our study supports the clinical utility of Pg infection assessment in patients with periodontitis and those with AF and solicits more focused studies to corroborate its use in clinical settings to enhance overall outcomes, reduce the risk of complications like stroke, and help fine-tune personalized therapies.

The Oral Microbiota, Microbial Metabolites, and Immuno-Inflammatory Mechanisms in Cardiovascular Disease

Cardiovascular diseases (CVDs) remain a leading cause of global morbidity and mortality. Recent advancements in high-throughput omics techniques have enhanced our understanding of the human microbiome's role in the development of CVDs. Although the relationship between the gut microbiome and CVDs has attracted considerable research attention and has been rapidly evolving in recent years, the role of the oral microbiome remains less understood, with most prior studies focusing on periodontitis-related pathogens. In this review, we summarized previously reported associations between the oral microbiome and CVD, highlighting known CVD-associated taxa such as Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans. We also discussed the interactions between the oral and gut microbes. The potential mechanisms by which the oral microbiota can influence CVD development include oral and systemic inflammation, immune responses, cytokine release, translocation of oral bacteria into the bloodstream, and the impact of microbial-related products such as microbial metabolites (e.g., short-chain fatty acids [SCFAs], trimethylamine oxide [TMAO], hydrogen sulfide [H2S], nitric oxide [NO]) and specific toxins (e.g., lipopolysaccharide [LPS], leukotoxin [LtxA]). The processes driven by these mechanisms may contribute to atherosclerosis, endothelial dysfunction, and other cardiovascular pathologies. Integrated multi-omics methodologies, along with large-scale longitudinal population studies and intervention studies, will facilitate a deeper understanding of the metabolic and functional roles of the oral microbiome in cardiovascular health. This fundamental knowledge will support the development of targeted interventions and effective therapies to prevent or reduce the progression from cardiovascular risk to clinical CVD events.

Exosomal miR-155-5p promote the occurrence of carotid atherosclerosis

Periodontitis is a significant independent risk factor for atherosclerosis. Yet, the exact mechanism of action is still not fully understood. In this study, we investigated the effect of exosomes-miR-155-5p derived from periodontal endothelial cells on atherosclerosis in vitro and in vivo. Higher expression of miR-155-5p was detected in the plasma exosomes of patients with chronic periodontitis (CP) and carotid atherosclerosis (CAS) compared to patients with CP. Also, the expression level of miR-155-5p was associated with the severity of CP. miR-155-5p-enriched exosomes from HUVECs increased the angiogenesis and permeability of HAECs and promoted the expression of angiogenesis, permeability, and inflammation genes. Along with the overexpression or inhibition of miR-155-5p, the biological effect of HUVECs-derived exosomes on HAECs changed correspondingly. In ApoE-/- mouse models, miR-155-5p-enriched exosomes promoted the occurrence of carotid atherosclerosis by increasing permeable and angiogenic activity. Collectively, these findings highlight a molecular mechanism of periodontitis in CAS, uncovering exosomal miR-155-5p derived periodontitis affecting carotid endothelial cells in an 'exosomecrine' manner. Exosomal miR-155-5p may be used as a biomarker and target for clinical intervention to control this intractable disease in future, and the graphic abstract was shown in Figure S1.

Periodontitis, Dental Procedures, and Young-Onset Cryptogenic Stroke

Periodontitis is associated with an increased risk of ischemic stroke, and the risk may be particularly high among young people with unexplained stroke etiology. Thus, we investigated in a case-control study whether periodontitis or recent invasive dental treatments are associated with young-onset cryptogenic ischemic stroke (CIS). We enrolled participants from a multicenter case-control SECRETO study including adults aged 18 to 49 y presenting with an imaging-positive first-ever CIS and stroke-free age- and sex-matched controls. Thorough clinical and radiographic oral examination was performed. Furthermore, we measured serum lipopolysaccharide (LPS) and lipotechoic acid (LTA) levels. Multivariate conditional regression models were adjusted for stroke risk factors, regular dentist visits, and patent foramen ovale (PFO) status. We enrolled 146 case-control pairs (median age 41.9 y; 58.2% males). Periodontitis was diagnosed in 27.5% of CIS patients and 20.1% of controls (P < 0.001). In the fully adjusted models, CIS was associated with high periodontal inflammation burden (odds ratio [OR], 95% confidence interval) with an OR of 10.48 (3.18-34.5) and severe periodontitis with an OR of 7.48 (1.24-44.9). Stroke severity increased with the severity of periodontitis, having an OR of 6.43 (1.87-23.0) in stage III to IV, grade C. Invasive dental treatments performed within 3 mo prestroke were associated with CIS, with an OR of 2.54 (1.01-6.39). Association between CIS and invasive dental treatments was especially strong among those with PFO showing an OR of 6.26 (1.72-40.2). LPS/LTA did not differ between CIS patients and controls but displayed an increasing trend with periodontitis severity. Periodontitis and recent invasive dental procedures were associated with CIS after controlling for multiple confounders. However, the role of bacteremia as a mediator of this risk was not confirmed.

Placental TLR recognition of salivary and subgingival microbiota is associated with pregnancy complications

BACKGROUND

Pre-term birth, the leading cause of neonatal mortality, has been associated with maternal periodontal disease and the presence of oral pathogens in the placenta. However, the mechanisms that underpin this link are not known. This investigation aimed to identify the origins of placental microbiota and to interrogate the association between parturition complications and immune recognition of placental microbial motifs. Video Abstract METHODS: Saliva, plaque, serum, and placenta were collected during 130 full-term (FT), pre-term (PT), or pre-term complicated by pre-eclampsia (PTPE) deliveries and subjected to whole-genome shotgun sequencing. Real-time quantitative PCR was used to measure toll-like receptors (TLR) 1-10 expression in placental samples. Source tracking was employed to trace the origins of the placental microbiota.

RESULTS

We discovered 10,007 functionally annotated genes representing 420 taxa in the placenta that could not be attributed to contamination. Placental microbial composition was the biggest discriminator of pregnancy complications, outweighing hypertension, BMI, smoking, and maternal age. A machine-learning algorithm trained on this microbial dataset predicted PTPE and PT with error rates of 4.05% and 8.6% (taxonomy) and 6.21% and 7.38% (function). Logistic regression revealed 32% higher odds of parturition complication (95% CI 2.8%, 81%) for every IQR increase in the Shannon diversity index after adjusting for maternal smoking status, maternal age, and gravida. We also discovered distinct expression patterns of TLRs that detect RNA- and DNA-containing antigens in the three groups, with significant upregulation of TLR9, and concomitant downregulation of TLR7 in PTPE and PT groups, and dense correlation networks between microbial genes and these TLRs. 70-82% of placental microbiota were traced to serum and thence to the salivary and subgingival microbiomes. The oral and serum microbiomes of PTPE and PT groups displayed significant enrichment of genes encoding iron transport, exosome, adhesion, quorum sensing, lipopolysaccharide, biofilm, and steroid degradation.

CONCLUSIONS

Within the limits of cross-sectional analysis, we find evidence to suggest that oral bacteria might translocate to the placenta via serum and trigger immune signaling pathways capable of inducing placental vascular pathology. This might explain, in part, the higher incidence of obstetric syndromes in women with periodontal disease.

Cytokine dysregulation despite immunoglobulin replacement therapy in common variable immunodeficiency (CVID)

Introduction

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiency. CVID is a heterogeneous disorder with a presumed multifactorial etiology. Intravenous or subcutaneous immunoglobulin replacement therapy (IgRT) can prevent severe infections but not underlying immune dysregulation.

Methods

In this study, we evaluated the serum concentrations of proinflammatory (TNF-α, IL-1β, IL-6) and immunoregulatory cytokines (IL-10), as well as lipopolysaccharide (LPS) and soluble CD14 (sCD14) in CVID individuals with infectious only (INF-CVID), and those with additional systemic autoimmune and inflammatory disorders (NIC-CVID), and healthy donors (HD).

Results

Our results showed increased serum concentrations of TNF-α, IL-1β, IL-6, and IL-10 in both INF-CVID and NIC-CVID subjects compared to HD. However, elevations of TNF-α, IL-1β, IL-6, and IL-10 were significantly more marked in NIC-CVID than INF-CVID. Additionally, LPS concentrations were increased only in NIC-CVID but not in INF-CVID compared to HD. Circulating levels of sCD14 were significantly increased in NIC-CVID compared to both INF-CVID and HD.

Discussion

These findings indicate persistent cytokine dysregulation despite IgRT in individuals with CVID. Moreover, the circulating cytokine profile reveals the heterogeneity of immune dysregulation in different subgroups of CVID subjects.

The role of the oral microbiome in smoking-related cardiovascular risk: a review of the literature exploring mechanisms and pathways

Cardiovascular disease is a leading cause of morbidity and mortality. Oral health is associated with smoking and cardiovascular outcomes, but there are gaps in knowledge of many mechanisms connecting smoking to cardiovascular risk. Therefore, the aim of this review is to synthesize literature on smoking and the oral microbiome, and smoking and cardiovascular risk/disease, respectively. A secondary aim is to identify common associations between the oral microbiome and cardiovascular risk/disease to smoking, respectively, to identify potential shared oral microbiome-associated mechanisms. We identified several oral bacteria across varying studies that were associated with smoking. Atopobium, Gemella, Megasphaera, Mycoplasma, Porphyromonas, Prevotella, Rothia, Treponema, and Veillonella were increased, while Bergeyella, Haemophilus, Lautropia, and Neisseria were decreased in the oral microbiome of smokers versus non-smokers. Several bacteria that were increased in the oral microbiome of smokers were also positively associated with cardiovascular outcomes including Porphyromonas, Prevotella, Treponema, and Veillonella. We review possible mechanisms that may link the oral microbiome to smoking and cardiovascular risk including inflammation, modulation of amino acids and lipids, and nitric oxide modulation. Our hope is this review will inform future research targeting the microbiome and smoking-related cardiovascular disease so possible microbial targets for cardiovascular risk reduction can be identified.

Periodontitis and cardiometabolic disorders: The role of lipopolysaccharide and endotoxemia

Lipopolysaccharide is a virulence factor of gram-negative bacteria with a crucial importance to the bacterial surface integrity. From the host's perspective, lipopolysaccharide plays a role in both local and systemic inflammation, activates both innate and adaptive immunity, and can trigger inflammation either directly (as a microbe-associated molecular pattern) or indirectly (by inducing the generation of nonmicrobial, danger-associated molecular patterns). Translocation of lipopolysaccharide into the circulation causes endotoxemia, which is typically measured as the biological activity of lipopolysaccharide to induce coagulation of an aqueous extract of blood cells of the assay. Apparently healthy subjects have a low circulating lipopolysaccharide activity, since it is neutralized and cleared rapidly. However, chronic endotoxemia is involved in the pathogenesis of many inflammation-driven conditions, especially cardiometabolic disorders. These include atherosclerotic cardiovascular diseases, obesity, liver diseases, diabetes, and metabolic syndrome, where endotoxemia has been recognized as a risk factor. The main source of endotoxemia is thought to be the gut microbiota. However, the oral dysbiosis in periodontitis, which is typically enriched with gram-negative bacterial species, may also contribute to endotoxemia. As endotoxemia is associated with an increased risk of cardiometabolic disorders, lipopolysaccharide could be considered as a molecular link between periodontal microbiota and cardiometabolic diseases.

Genetic Profile of Endotoxemia Reveals an Association With Thromboembolism and Stroke

Background Translocation of lipopolysaccharide from gram-negative bacteria into the systemic circulation results in endotoxemia. In addition to acute infections, endotoxemia is detected in cardiometabolic disorders, such as cardiovascular diseases and obesity. Methods and Results We performed a genome-wide association study of serum lipopolysaccharide activity in 11 296 individuals from 6 different Finnish study cohorts. Endotoxemia was measured by limulus amebocyte lysate assay in the whole population and by 2 other techniques (Endolisa and high-performance liquid chromatography/tandem mass spectrometry) in subpopulations. The associations of the composed genetic risk score of endotoxemia and thrombosis-related clinical end points for 195 170 participants were analyzed in FinnGen. Lipopolysaccharide activity had a genome-wide significant association with 741 single-nucleotide polymorphisms in 5 independent loci, which were mainly located at genes affecting the contact activation of the coagulation cascade and lipoprotein metabolism and explained 1.5% to 9.2% of the variability in lipopolysaccharide activity levels. The closest genes included KNG1, KLKB1, F12, SLC34A1, YPEL4, CLP1, ZDHHC5, SERPING1, CBX5, and LIPC. The genetic risk score of endotoxemia was associated with deep vein thrombosis, pulmonary embolism, pulmonary heart disease, and venous thromboembolism. Conclusions The biological activity of lipopolysaccharide in the circulation (ie, endotoxemia) has a small but highly significant genetic component. Endotoxemia is associated with genetic variation in the contact activation pathway, vasoactivity, and lipoprotein metabolism, which play important roles in host defense, lipopolysaccharide neutralization, and thrombosis, and thereby thromboembolism and stroke.

Systemic burden and cardiovascular risk to Porphyromonas species in apical periodontitis

OBJECTIVE

Porphyromonas (P.) species (spp.) are a major etiological agent of apical periodontitis (AP), which in turn represents a risk factor for cardiovascular diseases. This study explored the associations between endodontic infection with Porphyromonas species, the systemic bacterial burden, and cardiovascular risk, based on high-sensitivity C-reactive protein (hsCRP), in young adults with AP.

MATERIALS AND METHODS

Cross-sectional study. Otherwise, healthy individuals with AP and controls (n = 80, ≤ 40 years) were recruited at the University Dental Clinic. Oral parameters and classic cardiovascular risk factors were registered. Endodontic Porphyromonas endodontalis and Porphyromonas gingivalis were identified using conventional PCR. Serum concentrations of anti-P. endodontalis and anti-P. gingivalis antibodies, and endotoxins were determined through ELISA and Limulus-amebocyte assays. Serum hsCRP was determined for cardiovascular risk stratification.

RESULTS

Intracanal detection of P. endodontalis and P. gingivalis in AP were 33.3% and 22.9%, respectively. Serum anti-P. endodontalis and anti-P. gingivalis IgG was higher in AP than controls (p < 0.05 and p = 0.057, respectively). Intracanal P. endodontalis associated with higher endotoxemia (p < 0.05). Among endodontic factors, the presence (OR 4.2-5.5, p < 0.05) and the number of apical lesions (OR 2.3, p < 0.05) associated with moderate-severe cardiovascular risk, whereas anti-P. endodontalis IgG were protective (OR 0.3, p > 0.05).

CONCLUSIONS

AP and infection with P. endodontalis positively associated with cardiovascular risk based on hsCRP levels and endotoxemia, respectively, whereas anti-P. endodontalis IgG response seems to be protective against low-grade systemic inflammation.

CLINICAL RELEVANCE

Apical periodontitis and endodontic P. endodontalis can influence the systemic burden with impact on the surrogate cardiovascular risk marker hsCRP, providing mechanistic links.

Bacterial Lipase Neutralized Toxicity of Lipopolysaccharide on Chicken Embryo Cardiac Tissue

It has been shown that near all organs, especially the cardiovascular system, are affected by bacterial lipopolysaccharide via the activation of Toll-like receptor signaling pathways. Here, we tried to find the blunting effect of bacterial lipase on lipopolysaccharide (LPS)-induced cardiac tissue toxicity in chicken embryos. 7-day fertilized chicken eggs were divided randomly into different groups as follows; Control, Normal Saline, LPS (0.1, 0.5 and 1 mg/kbw), and LPS (0.1, 0.5 and 1 mg/kbw) plus 5 mg/ml Lipase. On day 17, the hearts were sampled. The expression of genes such as GATA4, NKX2.5, EGFR, TRIF, and NF-ƙB was monitored using real-time PCR analysis. Using western blotting, we measured NF-ƙB protein level. Total antioxidant capacity, glutathione peroxidase, and Catalase activity were also studied. Microvascular density and anterior wall thickness were monitored in histological samples using H&E staining. High dose of LPS (1 mg/kbw) increased the expression of TRIF but not NF-ƙB compared to the control group (p < 0.05). We found a statistically significant reduction in groups that received LPS + Lipase compared to the control and LPS groups (p < 0.05). Western blotting revealed that the injection of Lipase could reduce LPS-induced NF-ƙB compared to the control group (p < 0.05). The expression of GATA4, NKx2.5, and EGFR was not altered in the LPS group, while the simultaneous application of LPS and Lipase significantly reduced GATA4, NKx2.5, and EGFR levels below the control (p < 0.05). We found non-significant differences in glutathione peroxidase, and Catalase activity in all groups (p > 0.05), while total antioxidant capacity was increased in groups that received LPS + Lipase. Anterior wall thickness was diminished in LPS groups and the use of both lipase and LPS returned near-to-control values (p < 0.05). Despite a slight increase in microvascular density, we found statistically non-significant differences in all groups (p > 0.05). Bacterial lipase reduces detrimental effects of LPS on chicken embryo heart induced via Toll-like receptor signaling pathway.