Downregulation of interleukin 6 signaling might reduce the risk of periodontitis: a drug target Mendelian randomization study

Review of the mechanism of infection induced cerebral small vessel disease

Cerebral small vessel disease (CSVD) refers to a group of pathological syndromes that affect the brain's microcirculation. These conditions involve damage to small arteries, arterioles, capillaries, venules, and small veins. Cerebrovascular risk factors, immunosenescence, and inflammatory responses contribute to the pathogenesis of cerebral small vessel disease. The global impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has drawn significant attention to chronic inflammation caused by infections. Research into the mechanisms by which infections induce CSVD has made continual advancements. It is imperative to reassess the importance of managing infections and the chronic inflammatory phase that follows, highlighting their critical role in the pathogenesis. Our focus encompasses SARS-CoV-2, Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), Zika Virus(ZIKV), Treponema pallidum, as well as the microbial communities within the gut and oral cavity. These pathogen infections and chronic inflammation can contribute to CSVD through mechanisms such as neuroinflammation, blood-brain barrier disruption, microthrombosis, and endothelial cell damage, thereby promoting the occurrence and progression of the disease. This highlights the need for detailed mechanistic research on CSVD associated with these pathogens. Furthermore, we hope that in the future, we will be able to devise targeted prevention and treatment strategies for CSVD based on the unique characteristics of the pathogenic mechanisms associated with various infections.

Evaluating the Efficacy of Resveratrol-Containing Mouthwash as an Adjunct Treatment for Periodontitis: A Randomized Clinical Trial

OBJECTIVES

 To evaluate the effectiveness of resveratrol mouthwash as an adjunct to nonsurgical periodontal treatment of periodontitis.

MATERIALS AND METHODS

 This study was a randomized, double-blind clinical trial study. The study included 57 participants with periodontitis. Clinical parameters (plaque index [PI], bleeding on probing [BOP], probing pocket depth [PPD], and clinical attachment loss [CAL]) were examined at the baseline visit, after 7 days, and after 30 days of using resveratrol mouthwash as an adjunct to nonsurgical periodontal treatment. The salivary levels of (interleukin [IL]-6) and RANKL (receptor activator of nuclear factor-kappa B ligand) were measured and compared before and after treatment. The participants answered the visual analog scale-based assessment questionnaire at the last visit.

STATISTICAL ANALYSIS

 A one-way ANOVA (analysis of variance) test was used to compare the means of multiple groups (test, positive control, negative control) at baseline and after treatment. A paired t-test was also used to compare the means of a single group before and after treatment. In addition, Tukey's multiple comparisons test was used to identify specific pairwise differences between the three groups after finding significant differences with ANOVA. The Chi-square test was also used to compare the distribution of categorical variables like sex between the groups.

RESULTS

 All interventions significantly reduced PI, BOP, PPD, and CAL, but resveratrol and chlorhexidine had a higher significant effect than placebo except for CAL without a significant difference between them. All mouthwashes significantly reduced the salivary concentration of IL-6. However, resveratrol and chlorhexidine had a significantly higher effect than placebo, while the concentration of RANKL was decreased in all groups without a significant difference between them. The participants' responses to the mouthwash questionnaire showed that resveratrol and chlorhexidine had the same feedback without significant differences.

CONCLUSION

 Resveratrol-containing mouthwash could be used as an alternative to chlorhexidine as an adjunct to nonsurgical periodontal treatment of periodontitis.

Exploring Relationships Between Circulating Interleukins and Pulp and Periapical Diseases: A Bidirectional Mendelian Randomization Study

INTRODUCTION

The aim of this study was to comprehensively evaluate the links of genetic predisposition among 13 common circulating interleukins (ILs) and endodontic diseases by using a 2-sample Mendelian randomization method.

METHODS

Single nucleotide polymorphisms were chosen as instrumental variables from summary data of genome-wide association studies (GWASs), using the inverse-variance-weighted method as the primary analysis. In addition, a variety of sensitivity analyses was conducted to evaluate the resilience of the primary outcomes and identify any inherent pleiotropic effects.

RESULTS

After multiple comparison corrections, 4 circulating ILs were genetically predicted to significantly play a role in endodontic diseases. Among these, circulating IL-17 (odds ratio [OR]IVW, 1.33; 95% confidence interval [CI], 1.15-1.54; P < 3.85 × 10-3) were significantly identified as potential risk-increasing factors toward pulp and periapical diseases, and circulating IL-16 (ORIVW, 0.89; 95% CI, 0.83 to 0.94; P < 3.85 × 10-3) may exert protective effects on the development of periapical abscess. In the reverse analyses, null significantly association was found between genetic liability to endodontics disorders and the corresponding circulating inflammatory biomarkers. Overall, sensitivity analyses were consistent with the estimates direction of primary analyses results, supporting the reliability of findings.

CONCLUSIONS

Given the unavoidable limitations presented in this study, our findings provided significant evidence to support the identification of elevated IL-16 levels as a potential risk-mitigating factor, whereas elevated IL-17 levels exhibit potentially deleterious effects on endodontic disorders. Future validation is warranted to examine the conclusions of our study and to evaluate the potential application of these circulating ILs as lifestyle or pharmacological targets for oral health care.

Transcriptional regulation of human follicular dendritic cell-secreted protein gene by interleukin-6

Follicular dendritic cell-secreted protein (FDC-SP) is produced by follicular dendritic cells, periodontal ligament and junctional epithelium (JE). JE exists immediately apical to the bottom of the pocket and binds enamel with hemidesmosomes to protect the periodontium from bacterial infection. To analyze the transcriptional regulation of the FDC-SP gene by interleukin-6 (IL-6), we performed real-time PCR, Western blotting, immunofluorescence, luciferase (LUC) assays, gel mobility shift and chromatin immunoprecipitation (ChIP) assays using Ca9-22 and Sa3 gingival epithelial cells. IL-6 increased FDC-SP mRNA and protein levels at 3-24 h. IL-6 increased LUC activities of the LUC constructs containing FDC-SP gene promoter sequences from -116 to -717 bp upstream from the transcriptional start site. IL-6 induced LUC activities of -345FDCSP were inhibited by protein kinase A, tyrosine kinase, mitogen-activated protein kinase kinase, phosphoinositide 3-kinase, signal transducer, activator of transcription 3 (STAT3) and glycoprotein 130 inhibitors. Gel shift and ChIP assays showed that IL-6 induced Yin Yang1 (YY1), GATA binding protein (GATA), CCAAT/enhancer-binding protein (C/EBP) β, phosphorylated STAT3 (p-STAT3) binding to YY1, GATA, C/EBP2, C/EBP3 and GAS2-3 elements. These results indicate that IL-6 induces FDC-SP gene transcription YY1, GATA, C/EBP2, GAS2-3 and C/EBP3 elements in the human FDC-SP gene promoter, and suggesting that FDC-SP may be involved in the defense against JE in periodontium during the progression of periodontitis.

Population Proteomics: A Tool to Gain Insights Into the Inflamed Periodontium

Periodontitis, characterized by inflammatory loss of tooth-supporting tissues associated with biofilm, is among the most prevalent chronic diseases globally, affecting approximately 50% of the adult population to a moderate extent and cases of severe periodontitis surpassing the one billion mark. Proteomics analyses of blood, serum, and oral fluids have provided valuable insights into the complex processes occurring in the inflamed periodontium. However, until now, proteome analyses have been primarily limited to small groups of diseased versus healthy individuals. The emergence of population-scale analysis of proteomic data offers opportunities to uncover disease-associated pathways, identify potential drug targets, and discover biomarkers. In this review, we will explore the applications of proteomics in population-based studies and discuss the advancements it brings to our understanding of periodontal inflammation. Additionally, we highlight the challenges posed by currently available data and offer perspectives for future applications in periodontal research. This review aims to explain the ongoing efforts in leveraging proteomics for elucidating the complexities of periodontal diseases and paving the way for clinical strategies.

Clinical Outcomes and Cytokine Profile of Standard and Short Implant-supported Prostheses in Diabetics Treated for Periodontal Disease: A 5-year Study

PURPOSE

The present cross-sectional study aimed to assess the clinico-radiographic parameters as well as salivary levels of receptor activator of nuclear factor kappa-Β ligand (RANKL), osteoprotegerin (OPG), interleukin (IL)-6, and tumor necrosis factor-alpha (TNF-α) around standard and short dental implants (SDIs)-supported fixed partial denture in partially dentate type-II diabetes mellitus (T2DM) patients treated for periodontitis.

MATERIALS AND METHODS

The study comprised 4 groups: group 1 included T2DM patients with standard implants (n = 20); group II included non-T2DM patients with standard implants (n = 20); group III included T2DM patients with SDIs (n = 20); and group IV included non-T2DM patients with SDIs (n = 20). Participants eligible for the study included medically diagnosed T2DM patients with glycated hemoglobin (HbA1c) levels ≥ 6.5%, and non-T2DM participants with HbA1c levels between 4.0% and 5.0%. All had undergone previous periodontal therapy and had at least one standard implant and one SDI in the posterior maxillary or mandibular region. Exclusions were subjects with systemic conditions other than T2DM, recent use of steroids or antimicrobials, pregnancy or lactation, edentulism, misaligned dentition, or alcohol/tobacco use. Treatment involved non-surgical periodontal therapy, implant placement, and prosthetic procedures, with assessments including clinical (plaque index [PI], bleeding on probing [BOP], probing depth [PD]), radiographic (crestal bone loss [CBL]) parameters, and salivary cytokine levels including RANKL, OPG, IL-6, and TNF-α.

RESULTS

The study groups, each comprising 20 participants, showed no significant differences in demographics, restoration type, T2DM duration, family history, body mass index, or brushing routine (p>0.05). At baseline and 5-year follow-up, T2DM participants exhibited poorer periodontal parameters compared to non-T2DM, with higher PI (baseline: 62.2 ± 5.8% vs 29.6 ± 3.7%; 5-year follow-up: 69.2 ± 6.1% vs 32.8 ± 3.8%), BOP (baseline: 30.5 ± 3.2% vs 18.2 ± 2.6%; 5-year follow-up: 35.5 ± 3.9% vs 20.5 ± 2.5%), PD (baseline: 5.5 ± 1.1 mm vs 3.1 ± 0.9 mm; 5-year follow-up: 4.2 ± 0.8 mm vs 2.4 ± 0.7 mm), and CBL (baseline: 4.4 ± 0.4 mm vs 2.0 ± 0.2 mm; 5-yearfollow-up: 4.9 ± 0.5 mm vs 2.3 ± 0.3 mm), regardless of implant type. Salivary cytokine levels (RANKL, OPG, IL-6, TNF-α) were consistently higher in T2DM groups than non-T2DM across both implant types. Participants with SDIs showed comparable clinico-radiographic outcomes and salivary levels of cytokines to standard implants.

CONCLUSION

The application of SDI-supported rehabilitation in T2DM and non-diabetics showed comparable clinico-radiographic outcomes and salivary levels of cytokines to standard dental implants. Furthermore, T2DM patients exhibit poorer periodontal health and elevated inflammatory markers in patients with standard implants and SDIs.

Genetically Supported Drug Targets and Dental Traits: A Mendelian Randomization Study

Current interventions for oral/dental diseases heavily rely on operative/surgical procedures, while the discovery of novel drug targets may enable access to noninvasive pharmacotherapy. Therefore, this study aims to leverage large-scale data and Mendelian randomization (MR) techniques, utilizing genetic variants as instruments, to identify potential therapeutic targets for oral and dental diseases supported by genetic evidence. By intersecting 4,302 druggable genes with expression quantitative trait loci from 31,684 blood samples, we identified 2,580 druggable targets as exposures. Single nucleotide polymorphisms associated with dental disease/symptom traits were collected from FinnGen R9, the Gene-Lifestyle Interactions in Dental Endpoints consortium, and the UK Biobank to serve as outcomes for both discovery and replication purposes. Through MR analysis, we identified 43 druggable targets for various dental disease/symptom traits. To evaluate the viability of these targets, we replicated the analysis using circulating protein quantitative trait loci as exposures. Additionally, we conducted sensitivity, colocalization, Gene Ontology/Kyoto Encyclopedia of Genes and Genomes annotation, protein-protein interaction analyses, and validated dental trait-associated druggable gene expression in animal models. Among these targets, IL12RB1 (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.01-1.01) and TNF (OR, 0.98; 95% CI, 0.97-0.99) exhibited therapeutic promise for oral ulcers, whereas CXCL10 (OR, 0.84; 95% CI, 0.76-0.91) was for periodontitis. Through a rigorous quality control and validation pipeline, our study yields compelling evidence for these druggable targets, which may enhance the clinical prognosis by developing novel drugs or repurposing existing ones.

Periodontitis adversely affects lipoprotein subfractions - results from the cohort study SHIP-TREND: Periodontitis adversely affects lipoprotein subfractions

AIM

We aimed to investigate the medium-term associations of periodontitis and the number of missing teeth with serum lipoproteins and their plasma subfractions using follow-up data from the population-based Study of Health in Pomerania (SHIP-TREND).

METHODS

A total of 2,058 participants with 7-year follow-up data underwent periodontal examinations, serum lipid panel tests, and proton nuclear magnetic resonance (1H-NMR) spectroscopy of plasma lipoproteins and their subfractions. Generalized models with gamma distribution and loglink were used to analyze associations between periodontal variables and lipoproteins and their subfractions, adjusting for confounders using propensity score weighting.

RESULTS

Periodontal variables were consistently associated with elevated follow-up serum levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels. When plasma lipoprotein subfractions were evaluated, periodontal variables were associated with elevated levels of triglycerides and cholesterol-enriched apolipoprotein B-containing lipoprotein particles, particularly small dense low-density lipoprotein, very-low-density lipoprotein and intermediate density lipoprotein. In addition, altered high-density lipoprotein particle composition was observed, suggesting potential functional changes.

CONCLUSION

This study provides evidence for causal effects of periodontitis on conventional serum lipids and plasma lipoprotein subfractions. As the underlying biological mechanisms are not fully understood, further research is needed.

Mendelian randomization studies of periodontitis: Understanding benefits and natural limitations in an applied context

Mendelian randomization (MR) is a flexible analytical tool that has been widely applied to strengthen causal inference in observational epidemiology and is now gaining attention in many areas including periodontal research. The interpretation of results drawn from MR is based on a series of assumptions, which can be unrealistic or difficult to meet faithfully in some settings. However, we argue that with care, this does not necessarily prevent valuable deployment of the approach. We argue that clarity of presentation as well as careful assessment of specific analytical conditions is a fundamental part of all MR analyses. To that end, awareness of its limitations should also guide the design of MR investigations and the presentation of results rather than rule out its use altogether. Notably, considerations similar to those known to be important in conventional epidemiological settings apply to MR. While MR studies are valuable in their contrast to other study limitations, the application of this technique must be carefully cross-examined. Specific considerations include possible confounders, recruitment strategy and phenotypic measurement and differential analysis properties across studies. In the case of periodontal research, current MR applications are limited by the available evidence base for genetic contributions to periodontitis; however, this sets a specific scene for the strategic use of MR and shines light on a need for greater research emphasis on the genetics of the condition and intermediaries. This article provides a perspective on the uses and inherent limitations of MR studies and the importance of adhering to basic epidemiological principles when designing them.

Inhibition of DCUN1D1 attenuates periodontitis by suppressing NF-κB signaling

Nuclear factor kappa-B (NF-κB) signaling-mediated inflammation contributes greatly to the pathogenesis of periodontitis. Neddylation, a ubiquitin-like posttranslational modification, is known to regulate NF-κB signaling. DCUN1D1 (defective in cullin neddylation 1 domain containing 1) is a critical factor in neddylation and has been shown to regulate NF-κB activation. However, the previse roles of DCUN1D1 in periodontitis are not fully elucidated. To explore the roles of DCUN1D1 in periodontitis, the expression of DCUN1D1 was measured in gingival tissues of patients with periodontitis. We inhibited DCUN1D1 by siRNA knocking down or using inhibitor in gingival fibroblasts and the lipopolysaccharides (LPS)-induced expression of IL-6 and TNF-α, and activation of NF-κB were measured. The expression of DCUN1D1 was increased in gingival tissues of patients with periodontitis. Knocking down or inhibiting DCUN1D1 suppressed LPS-induced production of IL-6 and TNF-α, decreased NF-κB activity, and inhibited LPS-induced activation of NF-κB. Inhibiting DCUN1D1 ameliorates periodontitis by suppressing NF-κB signaling.

The impact of interleukin-6 (IL-6) and mesenchymal stem cell-derived IL-6 on neurological conditions

Interleukin-6 (IL-6) is a versatile cytokine crucial for immune response modulation, inflammation regulation, and various physiological processes in the body. Its wide-ranging functions underscore its importance in maintaining health. Dysregulated IL-6 is closely associated with many diseases, making it a key research and therapeutic target. Elevated IL-6 levels in the central nervous system worsen neuroinflammation in neurodegenerative diseases by activating microglia and astrocytes and releasing pro-inflammatory cytokines and neurotoxic molecules. Moreover, dysregulated IL-6 weakens the blood-brain barrier, exacerbating neuroinflammation and neuronal damage by allowing peripheral immune cells and inflammatory mediators to enter the brain. Mesenchymal stem cells (MSCs) show promise in modulating neuroinflammation by regulating IL-6 levels. They effectively suppress pro-inflammatory cytokines, including IL-6, while promoting anti-inflammatory factors. This therapeutic approach highlights the importance of targeting IL-6 and other inflammatory mediators to alleviate neuroinflammation and its adverse effects on neurological disorders. This review provides a comprehensive overview of IL-6's involvement in neurological disorders, examining endogenous IL-6 and IL-6 derived from MSCs. We explore IL-6's mechanisms affecting neuronal function, survival, and immune modulation in the central nervous system. Additionally, we discuss the potential of MSC-derived IL-6 in neuroregeneration and neuroprotection. By elucidating IL-6's interplay with neurological pathologies, this review offers insights into novel therapeutic strategies targeting IL-6 signaling pathways for neurological disorders.

Therapeutic potential of single-nucleotide polymorphism-mediated IL6R inhibitors in ankylosing spondylitis treatment

Objective

Interleukin-6 (IL-6) is a multiple-effect cell factor implicated in the etiopathogenesis of several rheumatologic disorders. The blockade of the IL-6 pathway via IL6R inhibitors effectively treats these disorders. However, the clinical significance of the IL6R blockade for ankylosing spondylitis (AS) therapy remains controversial. With advances in genomics, increasing evidence has revealed the role of heritability in the etiology of disease, and Mendelian randomization (MR) analyses are being used more broadly to infer causation. Therefore, this MR study aims to evaluate the potential therapeutic utility of IL6R-targeted approaches in AS.

Methods

The C-reactive protein (CRP) level was used as an exposure factor, and rheumatoid arthritis (RA) was used as a positive control. As-related genome-wide association study (GWAS) data were used as the primary outcome of drug-targeted MR analyses to test the relation between IL6R blockers and AS. Inverse variance weighting (IVW) is the primary analytical approach. Various sensitivity tests were performed to check the robustness and trustworthiness of the causality estimation, including consistency, heterogeneity, and pleiotropy analyses. In addition, repeated analysis was conducted using different GWAS data related to exposures and outcomes to examine the results for stability.

Results

According to the IVW results, IL6R inhibitors significantly reduced the risk of AS in ukb-b-18194 (OR: 0.995, 95% CI 0.993-0.996, P = 5.12 × 10-08) and ukb-a-88 (OR: 0.994, 95% CI 0.993-0.996, P = 6.25 × 10-15). Moreover, repeated analyses were performed using different exposure-related GWAS data, yielding similar results, ukb-b-18194 (OR: 0.995, 95% CI 0.993-0.997, P = 1.25 × 10-06) and ukb-a-88 (OR: 0.995, 95% CI 0.994-0.997, P = 7.81 × 10-09). Heterogeneity analyses and pleiotropy analyses indicated no significant heterogeneity or pleiotropy.

Conclusion

This MR analysis result further validates that the IL-6 pathway may contribute to the pathogenesis of AS and that the inhibition of IL6R reduces the risk of AS. These findings may guide future studies and provide more favorable drug treatment options for people at high risk of AS.

Interleukin-6 signaling pathway in Mendelian randomization: A 10-year bibliometric analysis

Interleukin 6 (IL-6), a pleiotropic cytokine, is crucial in a variety of inflammatory and immunological disorders. In recent years, mendelian randomization, which is a widely used and successful method of analyzing causality, has recently been investigated for the relationship between the IL-6 pathway and related diseases. However, no studies have been conducted to review the research hotspots and trends in the field of IL-6 signaling pathway in Mendelian randomization. In this study, the Web of Science Core Collection (WoSCC) served as our literature source database to gather articles about the IL-6 signaling pathway in Mendelian randomization from 2013 to 2023. VOSviewer (version 1.6.18), Microsoft Excel 2021, and Scimago Graphica were employed for bibliometric and visualization analysis. A total of 164 documents that were written by 981 authors coming from 407 institutions across 41 countries and published in 107 journals were located from January 2013 to August 2023. With 64 and 25, respectively, England and the University of Bristol had the highest number of publications. Frontiers in Immunology is the most prolific journal, and Golam M Khandaker has published the highest number of significant articles. The most co-cited article was an article entitled the interleukin-6 receptor as a target for prevention of coronary-heart-disease: a Mendelian randomization analysis, written by Daniel I Swerdlow. The most popular keywords were "mendelian randomization," "interleukin-6," "il-6," "c-reactive protein," "association," "coronary-heart-disease," "inflammation," "instruments," "risk," "rheumatoid arthritis," "depression." The full extent of the existing literature over the last 10 years is systematically revealed in this study, which can provide readers with a valuable reference for fully comprehending the research hotspots and trends in the field of IL-6 signaling pathway in Mendelian randomization.

Diabetes mellitus and prostate cancer risk: A mendelian randomization analysis

BACKGROUND

Some studies have directed towards an association between diabetes mellitus (DM) and prostate cancer (PCa); however, this specific relationship remains inconclusive. In recent years, Mendelian randomization (MR) has become a widely used analytical method for inferring epidemiological causes.

AIM

To investigated the potential relationship between DM and PCa using MR.

METHODS

We downloaded relevant data on "diabetes" and "PCa" from the IEU OpenGWAS project database, performed three different methods to conduct MR, and carried out sensitivity analysis for verification.

RESULTS

The results indicated that DM was an independent risk factor for PCa. The odds ratio (OR) values obtained using the inverse variance weighted method in this study were as follows: OR = 1.018 (95% confidence interval: 1.004-1.032), P = 0.014.

CONCLUSION

We found that DM could increase the incidence rate of PCa.