Porphyromonas gingivalis disrupts vascular endothelial homeostasis in a TLR-NF-κB axis dependent manner

P. Gingivalis induce macrophage polarization by regulating hepcidin expression in chronic apical periodontitis

INTRODUCTION

Hepcidin, a central regulatory molecule of iron metabolism, is upregulated through the IL-6/STAT3 signaling pathway in inflammatory and infectious states, contributing to the pathogenesis of various diseases. In chronic apical periodontitis (CAP), Porphyromonas gingivalis (P. gingivalis) and its lipopolysaccharides (LPS) activate various immune responses in vivo, contributing to disease progression. This study evaluated the role and mechanism of hepcidin in P. gingivalis-induced bone tissue damage in CAP, focusing on its promotion of macrophage M1 polarization via the IL-6/STAT3 signaling pathway.

METHODS

We analyzed a GSE77459 dataset from the GEO database, containing data from inflammatory and normal dental pulp tissues. RT-qPCR and immunofluorescence staining were used to detect the expression of hepcidin in human CAP tissues and its relationship with macrophages. Mouse bone marrow derived macrophages (BMDMs) were cultured in vitro and stimulated with P. gingivalis LPS. The effects of Stattic on macrophage hepcidin expression, IL-6 expression, STAT3 phosphorylation, and macrophage polarization were detected by ELISA, western blotting, RT-qPCR, and flow cytometry, respectively.

RESULTS

Hepcidin expression in human inflammatory dental pulp tissues was upregulated via the IL-6/STAT3 pathway and correlated with macrophage polarization. Hepcidin-encoding genes were found to be highly expressed and primarily associated with M1 macrophages in CAP tissues. In vitro experiments revealed that P. gingivalis LPS stimulation induced macrophages to express hepcidin through the IL-6/STAT3 pathway and polarize to M1. Additionally, the IL-6/STAT3 pathway inhibitor Stattic suppressed these changes.

CONCLUSIONS

Our study demonstrates that in CAP, macrophages highly express hepcidin, which subsequently alters macrophage metabolism, regulates M1 polarization, and leads to bone tissue destruction.

Porphyromonas gingivalis inducing autophagy-related biological dysfunction in alveolar epithelial cells: an in vitro study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a respiratory disease with high morbidity and mortality. Notably, the pathogenesis and progression of COPD are related to lung infection, inflammatory response, and biological dysfunction in alveolar epithelial cells. Studies also found that periodontitis is an independent risk factor for COPD. The inhalation of periodontal pathogens into the respiratory system is the most common method for periodontal pathogens to promote the development of COPD. Porphyromonas gingivalis (P. gingivalis), the keystone pathogen in periodontitis, has been found to migrate to the lungs, triggering inflammatory reactions and causing decreased lung function. However, the impact of P. gingivalis infection on the biological function of alveolar epithelial cells remains unclear. Therefore, this study aimed to investigate the effects of P. gingivalis infection on the biological functions of alveolar epithelial cells.

METHODS

Mouse alveolar epithelial cells (MLE-12) were co-cultured with P. gingivalis and treated with autophagy inhibitor chloroquine (CQ) or LC3 siRNA in vitro. MTT assay and EdU staining were used to detect cell viability, and the TUNEL assay kit and Annexin V-FITC/PI method were used to detect cell apoptosis. Western blot was used to detect autophagic markers LC3 and P62, and mRFP-GFP-LC3 was used to observe autophagic flux.

RESULTS

P. gingivalis inhibited the viability of alveolar epithelial cells in a dose- and time-dependent manner. P. gingivalis also promoted autophagy and apoptosis of alveolar epithelial cells in a dose-dependent manner. Interestingly, we found that inhibiting autophagy using CQ or silencing LC3 with siRNA significantly reduced cell apoptosis and viability damage induced by P. gingivalis. Thus, these data indicated the synergistic effect of autophagy in P. gingivalis-induced biological dysfunction of alveolar epithelial cells.

CONCLUSION

P. gingivalis infection can cause biological dysfunction of alveolar epithelial cells, manifested as decreased cell viability, increased autophagy and apoptosis. Notably, the up-regulation of autophagy induced by P. gingivalis plays a synergistic role in this dysfunction.

Exploring links between oral health and infective endocarditis

Infective endocarditis (IE) is a bacterial infection of the heart's inner lining. A low incidence rate combined with a high mortality rate mean that IE can be difficult to treat effectively. There is currently substantial evidence supporting a link between oral health and IE with the oral microbiome impacting various aspects of IE, including pathogenesis, diagnosis, treatment, and mortality rates. The oral microbiome is highly diverse and plays a crucial role in maintaining oral health by providing protective functions. However, when dysbiosis occurs, conditions such as periodontal or peri-implant disease can arise, offering a pathway for bacteraemia to develop. The role of the oral microbiome as a coloniser, facilitator and driver of IE remains to be uncovered by next-generation sequencing techniques. Understanding the dysbiosis and ecology of the oral microbiome of IE patients will allow improvements into the diagnosis, treatment, and prognosis of the disease. Furthermore, an increased awareness amongst those at high-risk of developing IE may encourage improved oral hygiene methods and lower incidence rates. This narrative review examines current findings on the relationship between oral health and IE. It draws from key studies on both topics, with manuscripts selected for their pertinence to the subject. It highlights the link between the oral microbiome and IE by exploring diagnostic techniques and treatments for IE caused by oral commensals.

Visualize the time dynamics and research trends of macrophage associated periodontitis research from 2004 to 2023: Bibliometrix analysis

BACKGROUND

Macrophages play an important role in the symptoms and structural progression of periodontitis, and are receiving increasing attention. In recent years, research has shown significant progress in macrophage associated periodontitis. However, there is still lack of comprehensive and methodical bibliometric analysis in this domain. Therefore, this research aims to describe the state of the research and current research hotspots of macrophage associated periodontitis from the perspective of bibliometrics.

METHODS

This study collected and screened a total of 1424 articles on macrophage associated periodontitis retrieved between 2004 and 2023 from Web of Science Core Collection database. Use Citespace (6.1. R6), Bibliometrix-R (4.1.3), VOSviewer (1.6.19), and Graphpad Prism8 software to analyze and plot countries/regions, institutions, journals, authors, literature, and keywords to explore the research hotspots and development trends of macrophage associated periodontitis.

RESULT

After analysis, the amount of macrophage associated periodontitis publications has been rising consistently over time, with China having the most publications (29.32%). 3 countries accounted for 65.57% of the total publications: the United States, China, and Japan, occupying a dominant position in this research field. China publications have the fastest growth rate and played a driving role. The most productive institution is the Sichuan University in China. Journal of Periodontal Research is highly popular in the field of macrophage associated periodontitis, with the highest number of publications. Grenier, Daniel is the most prolific author. Inflammation and Bone Loss in Periodontal Disease are the most cited literature. "Biological pathogenic factors," "immune regulation," "mechanism research," "susceptibility factor research," "pathological processes and molecular correlation," "pathological characteristics," "inflammatory response" are the main keyword groups in this field.

CONCLUSION

This study systematically analyzes and describes the development process, direction, and hotspots of macrophage associated periodontitis using bibliometric methods, providing a reference for future researchers who continue to study macrophage associated periodontitis.

Advances and challenges in the development of periodontitis vaccines: A comprehensive review

Periodontitis is a prevalent polymicrobial disease. It damages soft tissues and alveolar bone, and causes a significant public-health burden. Development of an advanced therapeutic approach and exploration of vaccines against periodontitis hold promise as potential treatment avenues. Clinical trials for a periodontitis vaccine are lacking. Therefore, it is crucial to address the urgent need for developing strategies to implement vaccines at the primary level of prevention in public health. A deep understanding of the principles and mechanisms of action of vaccines plays a crucial role in the successful development of vaccines and their clinical translation. This review aims to provide a comprehensive summary of potential directions for the development of highly efficacious periodontitis vaccines. In addition, we address the limitations of these endeavors and explore future possibilities for the development of an efficacious vaccine against periodontitis.

Analysis of vaginal flora diversity and study on the role of Porphyromonas asaccharolytica in promoting IL-1β in regulating cervical cancer

Cervical cancer, a prevalent malignancy in the female reproductive tract, exhibits a high incidence. Existing evidence indicates a robust correlation between alterations in vaginal flora composition and the progression of cervical cancer. Nevertheless, there is a lack of clarity concerning the specific microorganisms within the vaginal microbiota that are linked to the onset and development of cervical cancer, as well as the mechanisms through which they exert carcinogenic effects. The 16 S ribosomal (rRNA) and metagenomic sequencing technology were used to analyze vaginal microorganisms, and screening for human papillomavirus (HPV) positive cervical cancer-associated microbial markers using fold change in mean bacterial abundance. Moreover, vaginal microenvironmental factors were detected, and the local vaginal inflammatory state in patients with cervical cancer was subjected to assay via qRT-PCR and ELISA. The hub inflammatory genes were screened by transcriptome sequencing after co-culture of bacteria and normal cervical epithelial cells, and an in vitro model was utilized to assess the impacts of inflammatory factors on cervical cancer. Both cervical cancer patients and HPV-positive patients showed significant changes in the composition of the vaginal flora, characterised by a decrease in the abundance of Lactobacillus and an increase in the abundance of a variety of anaerobic bacteria; The microbial sequencing identified Porphyromonas, Porphyromonas_asaccharolytica, and Porphyromonas_uenonis as microbial markers for HPV-associated cervical cancer. Vaginal inflammatory factors in patients with cervical cancer were overexpressed. After Porphyromonas_asaccharolytica intervention on cervical epithelial H8 cells, interleukin (IL)-1β, a hub differential gene, markedly promoted tumor-associated biological behaviors at the in vitro cytological level in cervical cancer. This study for the first demonstrated that Porphyromonas, Porphyromonas_asaccharolytica, and Porphyromonas_uenonis could serve as novel microbial markers for cervical cancer. Moreover, Porphyromonas_asaccharolytica was identified as having the ability to induce the overexpression of inflammatory genes in cervical epithelial cells to create a favorable microenvironment for the onset and development of cervical cancer. The effects of dysbacteriosis on cervical cancer were microbiologically elucidated.

Engineering Versatile Bacteria-Derived Outer Membrane Vesicles: An Adaptable Platform for Advancing Cancer Immunotherapy

In recent years, cancer immunotherapy has undergone a transformative shift toward personalized and targeted therapeutic strategies. Bacteria-derived outer membrane vesicles (OMVs) have emerged as a promising and adaptable platform for cancer immunotherapy due to their unique properties, including natural immunogenicity and the ability to be engineered for specific therapeutic purposes. In this review, a comprehensive overview is provided of state-of-the-art techniques and methodologies employed in the engineering of versatile OMVs for cancer immunotherapy. Beginning by exploring the biogenesis and composition of OMVs, unveiling their intrinsic immunogenic properties for therapeutic appeal. Subsequently, innovative approaches employed to engineer OMVs are delved into, ranging from the genetic engineering of parent bacteria to the incorporation of functional molecules. The importance of rational design strategies is highlighted to enhance the immunogenicity and specificity of OMVs, allowing tailoring for diverse cancer types. Furthermore, insights into clinical studies and potential challenges utilizing OMVs as cancer vaccines or adjuvants are also provided, offering a comprehensive assessment of the current landscape and future prospects. Overall, this review provides valuable insights for researchers involved in the rapidly evolving field of cancer immunotherapy, offering a roadmap for harnessing the full potential of OMVs as a versatile and adaptable platform for cancer treatment.

Current status of superoxide dismutase 2 on oral disease progression by supervision of ROS

The recent Global Burden of Disease results have demonstrated that oral diseases are some of the most significant public health challenges facing the world. Owing to its specific localization advantage, superoxide dismutase 2 (SOD2 or MnSOD) has the ability to process the reactive oxygen species (ROS) produced by mitochondrial respiration before anything else, thereby impacting the occurrence and development of diseases. In this review, we summarize the processes of common oral diseases in which SOD2 is involved. SOD2 is upregulated in periodontitis to protect the tissue from the distant damage caused by excessive ROS and further reduce inflammatory progression. SOD2 also participates in the specific pathogenesis of oral cancers and dental diseases. The clinical application prospects of SOD2 in oral diseases will be discussed further, referencing the differences and relationship between oral diseases and other clinical systemic diseases.

The spatial transcriptomic landscape of human gingiva in health and periodontitis

The gingiva is a key oral barrier that protects oral tissues from various stimuli. A loss of gingival tissue homeostasis causes periodontitis, one of the most prevalent inflammatory diseases in humans. The human gingiva exists as a complex cell network comprising specialized structures. To understand the tissue-specific pathophysiology of the gingiva, we applied a recently developed spatial enhanced resolution omics-sequencing (Stereo-seq) technique to obtain a spatial transcriptome (ST) atlas of the gingiva in healthy individuals and periodontitis patients. By utilizing Stereo-seq, we identified the major cell types present in the gingiva, which included epithelial cells, fibroblasts, endothelial cells, and immune cells, as well as subgroups of epithelial cells and immune cells. We further observed that inflammation-related signalling pathways, such as the JAK-STAT and NF-κB signalling pathways, were significantly upregulated in the endothelial cells of the gingiva of periodontitis patients compared with those of healthy individuals. Additionally, we characterized the spatial distribution of periodontitis risk genes in the gingiva and found that the expression of IFI16 was significantly increased in endothelial cells of inflamed gingiva. In conclusion, our Stereo-seq findings may facilitate the development of innovative therapeutic strategies for periodontitis by mapping periodontitis-relevant genes and pathways and effector cells.

Cardiovascular diseases and the heart-gut cross talk

The purpose of this narrative review is to provide a comprehensive overview of current research on heart-gut cross talk and its implications for cardiovascular disease. To uncover relevant preclinical and clinical research examining heart-gut cross talk, a thorough literature search was undertaken utilising electronic databases. The chosen publications were critically examined, and major findings were synthesised to offer a thorough perspective on the subject. We want to synthesise the most recent study findings, explain the underlying mechanisms, and provide potential treatment techniques. By exploring bidirectional connection between the heart and the gut, we shed light on novel future options for the prevention and treatment of cardiovascular diseases. The heart-gut cross talk is an exciting field of study with implications for cardiovascular disease. Understanding the complex connection between the heart and the gastrointestinal tract may lead to the development of novel therapeutic targets and therapies for the prevention and management of cardiovascular diseases. Future research should concentrate on identifying the specific processes driving this crosstalk as well as assessing the efficacy of therapies targeting the gut microbiota and the gut-brain axis in improving cardiovascular outcomes.

Exploring the presence of oral bacteria in non-oral sites of patients with cardiovascular diseases using whole metagenomic data

Cardiovascular diseases (CVDs) encompass various conditions affecting the heart and its blood vessels and are often linked with oral microbes. Our data analysis aimed to identify oral bacteria from other non-oral sites (i.e., gut, arterial plaque and cultured blood) that could be linked with CVDs. Taxonomic profiling identified bacteria to the species level and compared with the Human Oral Microbiome Database (HOMD). The oral bacteria in the gut, cultured blood and arterial plaque samples were catalogued, with their average frequency calculated for each sample. Additionally, data were filtered by comparison with the Human Microbiome Project (HMP) database. We identified 17,243 microbial species, of which 410 were present in the HOMD database and further denominated as "oral", and were found in at least one gut sample, but only 221 and 169 species were identified in the cultured blood and plaque samples, respectively. Of the 410 species, 153 were present solely in oral-associated environments after comparison with the HMP database, irrespective of their presence in other body sites. Our results suggest a potential connection between the presence of specific species of oral bacterial and occurrence of CVDs. Detecting these oral bacterial species in non-oral sites of patients with CVDs could help uncover the link between oral health and general health, including cardiovascular conditions via bacterial translocation.

Regulation of toll-like receptor (TLR) signaling pathways in atherosclerosis: from mechanisms to targeted therapeutics

Atherosclerosis, one of the life-threatening cardiovascular diseases (CVDs), has been demonstrated to be a chronic inflammatory disease, and inflammatory and immune processes are involved in the origin and development of the disease. Toll-like receptors (TLRs), a class of pattern recognition receptors that trigger innate immune responses by identifying pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), regulate numerous acute and chronic inflammatory diseases. Recent studies reveal that TLRs have a vital role in the occurrence and development of atherosclerosis, including the initiation of endothelial dysfunction, interaction of various immune cells, and activation of a number of other inflammatory pathways. We herein summarize some other inflammatory signaling pathways, protein molecules, and cellular responses associated with TLRs, such as NLRP3, Nrf2, PCSK9, autophagy, pyroptosis and necroptosis, which are also involved in the development of AS. Targeting TLRs and their regulated inflammatory events could be a promising new strategy for the treatment of atherosclerotic CVDs. Novel drugs that exert therapeutic effects on AS through TLRs and their related pathways are increasingly being developed. In this article, we comprehensively review the current knowledge of TLR signaling pathways in atherosclerosis and actively seek potential therapeutic strategies using TLRs as a breakthrough point in the prevention and therapy of atherosclerosis.

The Roles of Periodontal Bacteria in Atherosclerosis

Atherosclerosis (AS) is an inflammatory vascular disease that constitutes a major underlying cause of cardiovascular diseases (CVD) and stroke. Infection is a contributing risk factor for AS. Epidemiological evidence has implicated individuals afflicted by periodontitis displaying an increased susceptibility to AS and CVD. This review concisely outlines several prevalent periodontal pathogens identified within atherosclerotic plaques, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum. We review the existing epidemiological evidence elucidating the association between these pathogens and AS-related diseases, and the diverse mechanisms for which these pathogens may engage in AS, such as endothelial barrier disruption, immune system activation, facilitation of monocyte adhesion and aggregation, and promotion of foam cell formation, all of which contribute to the progression and destabilization of atherosclerotic plaques. Notably, the intricate interplay among bacteria underscores the complex impact of periodontitis on AS. In conclusion, advancing our understanding of the relationship between periodontal pathogens and AS will undoubtedly offer invaluable insights and potential therapeutic avenues for the prevention and management of AS.

The Diagnostic Potential of the Human Blood Microbiome: Are We Dreaming or Awake?

Human blood has historically been considered a sterile environment. Recently, a thriving microbiome dominated by Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes phyla was detected in healthy blood. The localization of these microbes is restricted to some blood cell populations, particularly the peripheral blood mononuclear cells and erythrocytes. It was hypothesized that the blood microbiome originates from the skin-oral-gut axis. In addition, many studies have evaluated the potential of blood microbiome dysbiosis as a prognostic marker in cardiovascular diseases, cirrhosis, severe liver fibrosis, severe acute pancreatitis, type 2 diabetes, and chronic kidney diseases. The present review aims to summarize current findings and most recent evidence in the field.

Porphyromonas gingivalis regulates atherosclerosis through an immune pathway

Atherosclerosis (AS) is a chronic inflammatory disease, involving a pathological process of endothelial dysfunction, lipid deposition, plaque rupture, and arterial occlusion, and is one of the leading causes of death in the world population. The progression of AS is closely associated with several inflammatory diseases, among which periodontitis has been shown to increase the risk of AS. Porphyromonas gingivalis (P. gingivalis), presenting in large numbers in subgingival plaque biofilms, is the “dominant flora” in periodontitis, and its multiple virulence factors are important in stimulating host immunity. Therefore, it is significant to elucidate the potential mechanism and association between P. gingivalis and AS to prevent and treat AS. By summarizing the existing studies, we found that P. gingivalis promotes the progression of AS through multiple immune pathways. P. gingivalis can escape host immune clearance and, in various forms, circulate with blood and lymph and colonize arterial vessel walls, directly inducing local inflammation in blood vessels. It also induces the production of systemic inflammatory mediators and autoimmune antibodies, disrupts the serum lipid profile, and thus promotes the progression of AS. In this paper, we summarize the recent evidence (including clinical studies and animal studies) on the correlation between P. gingivalis and AS, and describe the specific immune mechanisms by which P. gingivalis promotes AS progression from three aspects (immune escape, blood circulation, and lymphatic circulation), providing new insights into the prevention and treatment of AS by suppressing periodontal pathogenic bacteria.

Alzheimer's Disease: A Systems View Provides a Unifying Explanation of Its Development

Alzheimer's disease (AD) is a debilitating neurodegenerative disorder affecting 50 million people globally. It is characterized by the presence of extracellular senile plaques and intracellular neurofibrillary tangles, consisting of amyloid-β and hyperphosphorylated tau proteins, respectively. Despite global research efforts, there is currently no cure available, due in part to an incomplete understanding of the disease pathogenesis. Numerous possible mechanisms, or hypotheses, explaining the origins of sporadic or late-onset AD have been proposed, including the amyloid-β, inflammatory, vascular, and infectious hypotheses. However, despite ample evidence, the failure of multiple trial drugs at the clinical stage illuminates the possible pitfalls of these hypotheses. Systems biology is a strategy which aims to elucidate the interactions between parts of a whole. Using this approach, the current paper shows how the four previously mentioned hypotheses of AD pathogenesis can be intricately connected. This approach allows for seemingly contradictory evidence to be unified in a system-focused explanation of sporadic AD development. Within this view, it is seen that infectious agents, such as P. gingivalis, may play a central role. The data presented here shows that when present, P. gingivalis or its virulence factors, such as gingipains, may induce or exacerbate pathologies underlying sporadic AD. This evidence supports the view that infectious agents, and specifically P. gingivalis, may be suitable treatment targets in AD.

[Developments in Research on the Relationship Between Porphyromonas gingivalis and Non-Oral Diseases]

Porphyromonas gingivalis ( P. gingivalis) is a common periodontal pathogen. Recently, there has been increasing evidence suggesting that P. gingivalis is not only a common pathogen in the oral cavity, but is also closely associated with non-oral diseases, including inflammatory bowel disease, cancer, cardiovascular diseases, Alzheimer's disease, rheumatoid arthritis, diabetes mellitus, premature birth and non-alcoholic hepatitis, etc. Herein, we reviewed the developments in recent years in research on the relationship between P. gingivalis, a periodontal pathogen, and non-oral diseases, which will help determine whether P. gingivalis could be used as an auxiliary diagnostic biomarker or a potential therapeutic target for these non-oral diseases, thus contributing to the development of treatment strategies for the relevant diseases.

The interplay between oral microbes and immune responses

Oral microbes play a critical role in maintaining oral homeostasis. Microbial dysbiosis promotes disease pathogenesis through several mechanisms. Recent studies have revealed that microbial imbalance and sustained inflammation are involved in disease progression. The adverse interaction triggered by a host immune response to microorganisms can lead to oral and systemic diseases. Here, we reviewed how oral microbes communicate with hosts during the development of local and distant inflammation. Elucidation of these processes may reveal future directions in this field and the potential targets of novel biological therapies for oral and systemic diseases.

Porphyromonas gingivalis Virulence Factors and Clinical Significance in Periodontal Disease and Coronary Artery Diseases

Porphyromonas gingivalis is a gram-negative, anaerobic bacterium that lives in the oral cavity. It is an integral part of the oral microbiome, which includes more than 500 types of bacteria. Under certain circumstances, as a consequence of virulence factors, it can become very destructive and proliferate to many cells in periodontal lesions. It is one of the causative agents present extremely often in dental plaque and is the main etiological factor in the development of periodontal disease. During various therapeutic procedures, P. gingivalis can enter the blood and disseminate through it to distant organs. This primarily refers to the influence of periodontal agents on the development of subacute endocarditis and can facilitate the development of coronary heart disease, atherosclerosis, and ischemic infarction. The action of P. gingivalis is facilitated by numerous factors of virulence and pathogenicity such as fimbriae, hemolysin, hemagglutinin, capsules, outer membrane vesicles, lipopolysaccharides, and gingipains. A special problem is the possibility of biofilm formation. P. gingivalis in a biofilm is 500 to 1000 times less sensitive to antimicrobial drugs than planktonic cells, which represents a significant problem in the treatment of infections caused by this pathogen.

Association between periodontitis and heart failure in the general population

AIMS

Data on the association between periodontitis and preclinical cardiac alterations remain scarce. The aim of the current study is to determine if periodontitis is associated with morphological and functional cardiac changes measured by transthoracic echocardiography as well as different heart failure (HF) phenotypes.

METHODS

Participants from the population-based Hamburg City Health Study [ClinicalTrial.gov (NCT03934957)], who underwent transthoracic echocardiography and periodontal screening were included. Periodontitis was classified according to Eke and Page (none/mild, moderate, severe). The 2021 ESC HF guidelines were applied and HF was classified into HF with preserved ejection fraction (HFpEF, ejection fraction ≥50%), HF with mid-range and reduced ejection fraction [HF(m)rEF, ejection fraction <50%], and HF in general [HFpEF and HF(m)rEF]. Due to limited size, all subjects with LVEF <50% and symptoms or signs of HF were classified as HF with reduced and mildly reduced ejection fraction [HF(m)rEF].

RESULTS

Within 6209 participants with full periodontal examination, we identified an overlap of n = 167 participants with periodontitis and HF. Participants with severe periodontitis showed a higher burden of cardiovascular risk factors (men at advanced age, diabetes mellitus, hypertension) when compared with participants with none/mild periodontitis. After adjustment for age, sex, body mass index, smoking, diabetes, hypertension, atrial fibrillation, and coronary artery disease, severe periodontitis was significantly associated with HF(m)rEF (odds ratio: 3.16; 95% CI: 1.21, 8.22; P = 0.019), although no association was found for HFpEF and HF in general.

CONCLUSIONS

The current study demonstrated that severe periodontitis was significantly associated with HF(m)rEF, although no relevant associations were found with HFpEF and HF in general as well as echocardiographic variables. The results implicate a potential target group, who need special attention from cooperating physicians and dentists. Future studies are warranted to verify whether systemic inflammation could be the link between the two diseases.

Interaction Between Autophagy and Porphyromonas gingivalis-Induced Inflammation

Autophagy is an immune homeostasis process induced by multiple intracellular and extracellular signals. Inflammation is a protective response to harmful stimuli such as pathogen microbial infection and body tissue damage. Porphyromonas gingivalis infection elicits both autophagy and inflammation, and dysregulation of autophagy and inflammation promotes pathology. This review focuses on the interaction between autophagy and inflammation caused by Porphyromonas gingivalis infection, aiming to elaborate on the possible mechanism involved in the interaction.

Deciphering mechanisms and implications of bacterial translocation in human health and disease

Significant increases in potential microbial translocation, especially along the oral-gut axis, have been identified in many immune-related and inflammatory diseases, such as inflammatory bowel disease, colorectal cancer, rheumatoid arthritis, and liver cirrhosis, for which we currently have no cure or long-term treatment options. Recent advances in computational and experimental omics approaches now enable strain tracking, functional profiling, and strain isolation in unprecedented detail, which has the potential to elucidate the causes and consequences of microbial translocation. In this review, we discuss current evidence for the detection of bacterial translocation, examine different translocation axes with a primary focus on the oral-gut axis, and outline currently known translocation mechanisms and how they adversely affect the host in disease. Finally, we conclude with an overview of state-of-the-art computational and experimental tools for strain tracking and highlight the required next steps to elucidate the role of bacterial translocation in human health.

Periodontitis exacerbates endothelial dysfunctions partly via endothelial-mesenchymal transition in streptozotocin-induced diabetes rats

OBJECTIVES

Periodontal infections are related to the expansion of diabetes cardiovascular problems. However, the pathological process and probable mechanism remain unexplained. This study investigated the impact of periodontitis on streptozotocin (STZ)-induced diabetes rats' carotid artery.

METHODS

We randomized 24 Sprague-Dawley (SD) rats into four groups: control, chronic periodontitis (CP), diabetes mellitus (DM), and DM +CP groups. Fasting blood glucose (FBG) and hemoglobin A_1c (HBA_1c ) were measured to verify the establishment of the DM model. After euthanasia, the maxillary was collected for further studies like hematoxylin-eosin (HE), Masson staining, and micro-computed tomography (micro-CT) analysis. Immunofluorescence (IF) staining was used to detect endothelial-mesenchymal transition (EndMT)-related markers in carotid artery wall. We further used ELISA and quantitative real-time PCR to investigate the effect of high glucose (HG) and Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) on human umbilical vein endothelial cells (HUVECs).

RESULTS

Compared with DM and CP groups, bone resorption and pathological changes of the vascular wall were the most serious in the DM+CP group. The vascular wall of the DM+CP group had a higher level of interleukin (IL)-6 and vascular cell adhesion molecule 1 (VCAM-1). The carotid artery vascular wall of the DM+CP group contained more cells that expressed both mesenchymal and endothelial cell markers, along with elevated transcription factor levels. Furthermore, P.g-LPS and HG upregulated the inflammatory cytokines expression and caused phenotypic changes of HUVECs in vitro.

CONCLUSION

Periodontitis exacerbates endothelial dysfunctions partly via endothelial-mesenchymal transition in STZ-induced diabetes rats.

Effects of BMAL1 on dentinogenic differentiation of Dental Pulp Stem Cells via PI3K / Akt / mTOR pathway

AIM

The present study was aimed to investigate the effect of the circadian clock gene Bmal1 on dentinogenic differentiation of dental pulp stem cells (DPSCs) under inflammatory conditions.

METHODOLOGY

DPSCs were isolated from the pulp tissue of the healthy donor and were then stimulated with different concentrations of lipopolysaccharide (LPS) to mimic inflammatory conditions. Real-time polymerase chain reaction (PCR) was used to detect the gene expression of circadian clock genes Bmal1, Clock, Per1, Per2, Cry1, and Cry2. Western blot (WB) was applied to analyze the protein expression of circadian clock proteins (BMAL1, CLOCK) and dentinogenic differentiation related proteins (DSPP, DMP1). In addition, the apoptosis and osteogenic differentiation of DPSCs were also analyzed in the presence of different concentrations of LPS.

RESULTS

The expression of circadian clock genes of DPSCs significantly changed in an inflammatory environment. WB analysis shows that BMAL1 is relevant to the dentinogenic differentiation of DPSCs. In low concentrations of LPS-mimicked inflammatory condition, the expression of BMAL1 increased and promoted the dentinogenic differentiation of DPSCs. However, under high concentrations of LPS-mimicked inflammatory condition, the expression of BMAL1 decreased and inhibited the dentinogenic differentiation of DPSCs. Moreover, the effects of BMAL1 on dentinogenic differentiation of DPSCs may be through PI3K / Akt / mTOR pathway.

CONCLUSIONS

This study showed that the circadian clock gene Bmal1 affected dentinogenic differentiation of DPSCs, providing a new insight for clinical stem cell-based restorative dentinogenesis therapies.

Periodontopathic Microbiota and Atherosclerosis: Roles of TLR-Mediated Inflammation Response

Atherosclerosis is a chronic inflammatory disease with a high prevalence worldwide, contributing to a series of adverse cardiovascular and cerebrovascular diseases. Periodontal disease induced by pathogenic periodontal microbiota has been well established as an independent factor of atherosclerosis. Periodontal microorganisms have been detected in atherosclerotic plaques. The high-risk microbiota dwelling in the subgingival pocket can stimulate local and systematic host immune responses and inflammatory cascade reactions through various signaling pathways, resulting in the development and progression of atherosclerosis. One often-discussed pathway is the Toll-like receptor-nuclear factor-κB (TLR-NF-κB) signaling pathway that plays a central role in the transduction of inflammatory mediators and the release of proinflammatory cytokines. This narrative review is aimed at summarizing and updating the latest literature on the association between periodontopathic microbiota and atherosclerosis and providing possible therapeutic ideas for clinicians regarding atherosclerosis prevention and treatment.

The Effects of Porphyromonas gingivalis on Atherosclerosis-Related Cells

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

Unexpected Relationships: Periodontal Diseases: Atherosclerosis-Plaque Destabilization? From the Teeth to a Coronary Event

Atherosclerotic cardiovascular disease (ASCVD) and periodontal disease (PD) are global health problems. High frequency of ASCVD is associated with the spread of many risk factors, including poor diet, sedentary lifestyle, diabetes, hyperlipidemia, obesity, smoking, hypertension, chronic kidney disease, hypertension, hyperhomocysteinemia, hyperuricemia, excessive stress, virus infection, genetic predisposition, etc. The pathogenesis of ASCVD is complex, while inflammation plays an important role. PD is a chronic, multifactorial inflammatory disease caused by dysbiosis of the oral microbiota, causing the progressive destruction of the bone and periodontal tissues surrounding the teeth. The main etiological factor of PD is the bacteria, which are capable of activating the immune response of the host inducing an inflammatory response. PD is associated with a mixed microbiota, with the evident predominance of anaerobic bacteria and microaerophilic. The "red complex" is an aggregate of three oral bacteria: Tannerella forsythia Treponema denticola and Porphyromonas gingivalis responsible for severe clinical manifestation of PD. ASCVD and PD share a number of risk factors, and it is difficult to establish a causal relationship between these diseases. The influence of PD on ASCVD should be treated as a factor increasing the risk of atherosclerotic plaque destabilization and cardiovascular events. The results of observational studies indicate that PD significantly increases the risk of ASCVD. In interventional studies, PD treatment was found to have a beneficial effect in the prevention and control of ASCVD. This comprehensive review summarizes the current knowledge of the relationship between PD and ASCVD.

Association between metabolic syndrome and periodontitis: The role of lipids, inflammatory cytokines, altered host response, and the microbiome

Periodontitis has been associated with many systemic diseases and conditions, including metabolic syndrome. Metabolic syndrome is a cluster of conditions that occur concomitantly and together they increase the risk of cardiovascular disease and double the risk of type 2 diabetes. In this review, we focus on the association between metabolic syndrome and periodontitis; however, we also include information on diabetes mellitus and cardiovascular disease, since these two conditions are significantly intertwined with metabolic syndrome. With regard to periodontitis and metabolic syndrome, to date, the vast majority of studies point to an association between these two conditions and also demonstrate that periodontitis can contribute to the development of, or can worsen, metabolic syndrome. Evaluating the effect of metabolic syndrome on the salivary microbiome, data presented herein support the hypothesis that the salivary bacterial profile is altered in metabolic syndrome patients compared with healthy patients. Considering periodontitis and these three conditions, the vast majority of human and animal studies point to an association between periodontitis and metabolic syndrome, diabetes, and cardiovascular disease. Moreover, there is evidence to suggest that metabolic syndrome and diabetes can alter the oral microbiome. However, more studies are needed to fully understand the influence these conditions have on each other.

Porphyromonas gingivalis infection promotes mitochondrial dysfunction through Drp1-dependent mitochondrial fission in endothelial cells

Porphyromonas gingivalis (P. gingivalis), a key pathogen in periodontitis, has been shown to accelerate the progression of atherosclerosis (AS). However, the definite mechanisms remain elusive. Emerging evidence supports an association between mitochondrial dysfunction and AS. In our study, the impact of P. gingivalis on mitochondrial dysfunction and the potential mechanism were investigated. The mitochondrial morphology of EA.hy926 cells infected with P. gingivalis was assessed by transmission electron microscopy, mitochondrial staining, and quantitative analysis of the mitochondrial network. Fluorescence staining and flow cytometry analysis were performed to determine mitochondrial reactive oxygen species (mtROS) and mitochondrial membrane potential (MMP) levels. Cellular ATP production was examined by a luminescence assay kit. The expression of key fusion and fission proteins was evaluated by western blot and immunofluorescence. Mdivi-1, a specific Drp1 inhibitor, was used to elucidate the role of Drp1 in mitochondrial dysfunction. Our findings showed that P. gingivalis infection induced mitochondrial fragmentation, increased the mtROS levels, and decreased the MMP and ATP concentration in vascular endothelial cells. We observed upregulation of Drp1 (Ser616) phosphorylation and translocation of Drp1 to mitochondria. Mdivi-1 blocked the mitochondrial fragmentation and dysfunction induced by P. gingivalis. Collectively, these results revealed that P. gingivalis infection promoted mitochondrial fragmentation and dysfunction, which was dependent on Drp1. Mitochondrial dysfunction may represent the mechanism by which P. gingivalis exacerbates atherosclerotic lesions.

Exacerbation of AMD Phenotype in Lasered CNV Murine Model by Dysbiotic Oral Pathogens

Emerging evidence underscores an association between age-related macular degeneration (AMD) and periodontal disease (PD), yet the biological basis of this linkage and the specific role of oral dysbiosis caused by PD in AMD pathophysiology remains unclear. Furthermore, a simple reproducible model that emulates characteristics of both AMD and PD has been lacking. Hence, we established a novel AMD+PD murine model to decipher the potential role of oral infection (ligature-enhanced) with the keystone periodontal pathogen Porphyromonas gingivalis, in the progression of neovasculogenesis in a laser-induced choroidal-neovascularization (Li-CNV) mouse retina. By a combination of fundus photography, optical coherence tomography, and fluorescein angiography, we documented inflammatory drusen-like lesions, reduced retinal thickness, and increased vascular leakage in AMD+PD mice retinae. H&E further confirmed a significant reduction of retinal thickness and subretinal drusen-like deposits. Immunofluorescence microscopy revealed significant induction of choroidal/retinal vasculogenesis in AMD+PD mice. qPCR identified increased expression of oxidative-stress, angiogenesis, pro-inflammatory mediators, whereas antioxidants and anti-inflammatory genes in AMD+PD mice retinae were notably decreased. Through qPCR, we detected Pg and its fimbrial 16s-RrNA gene expression in the AMD+PD mice retinae. To sum-up, this is the first in vivo study signifying a role of periodontal infection in augmentation of AMD phenotype, with the aid of a pioneering AMD+PD murine model established in our laboratory.