Periodontal inflammation and distinct inflammatory profiles in saliva and gingival crevicular fluid (GCF) compared with serum and joints in rheumatoid arthritis patients

Exploring the relationship between infectious agents and autoimmune diseases: a review

The relationship between infectious agents and autoimmune diseases is a complex issue. In recent years, increasing clinical cases have indicated that infectious agents play an important role in the development of autoimmune diseases. Molecular mimicry is currently widely regarded as the primary pathogenic mechanism of various autoimmune diseases in humans. Components of infectious agents can undergo molecular mimicry with components in patients' bodies, leading to the development of various autoimmune diseases. In this article, we provide a brief overview of current research of the current research status on the relationship between infectious agents and autoimmune diseases, and describe our current understanding of their mechanisms of action in order to better understand the pathogenesis, diagnosis, and treatment of autoimmune diseases.

Advances in periodontal biomarkers

Due to technologic advancements, periodontology has witnessed a boost in biomarker research over the past three decades. Indeed, with the aid of omics, our understanding of the healthy periodontium, pathogenesis of periodontal diseases, and healing after periodontal treatment has improved significantly. Yet, the traditional methods, periodontal probing and radiographies, remain the most common methods to diagnose periodontal disease and monitor treatment. Although these approaches can produce reliable diagnostic outcomes, they generally detect disease only after significant tissue degradation thus making treatment outcome highly uncertain. Accordingly, laboratories worldwide have collaborated with clinicians to design accurate, rapid and cost-effective biomarkers for periodontal disease diagnosis. Despite these efforts, biomarkers that can be widely used in early disease diagnosis and for treatment outcome prediction are far from daily use. The aim of this chapter is to give a general overview on periodontal health and diseases, and review recent advancements in periodontal biomarker research. A second aim will discuss the strengths and limitations of translating periodontal biomarker research to clinical practice. Genetic biomarkers of periodontitis are not discussed as the available confirmatory data is scarce.

Periodontitis and rheumatoid arthritis-Global efforts to untangle two complex diseases

Understanding the impact of oral health on rheumatoid arthritis (RA) will inform how best to manage patients with both periodontitis and RA. This review seeks to provide an update on interventional and mechanistic investigations, including a brief summary of European Research programs investigating the link between periodontitis and RA. Recent clinical studies are described that evaluate how the treatment of one disease impacts on the other, as are studies in both humans and animal models that have sought to identify the potential mechanisms linking the two diseases.

An In Vivo Investigation of Non-Metallic vs. Metallic Hand Scalers on Zirconia Implant-Supported Crowns: A Year-Long Analysis of Peri-Implant Maintenance

This study examined whether the degree of abutment surface modification that may occur with regular periodontal instrumentation has a clinical impact in terms of increased plaque accumulation and increased peri-implant tissue inflammation on zirconia implant abutments. Thirteen patients who had zirconia implant crowns were recruited in this randomized clinical trial. Each patient acted as their control and had either the buccal or lingual surface of their screw-retained implant restoration scaled with a metallic scaler and the other surface with a non-metallic scaler at 3, 6, 9, and 12 months. Cytokine testing of the peri-implant crevicular fluid was completed at 0, 3, and 12 months for IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, or IFNγ. Implant crowns were removed at 12 months and evaluated under an atomic force microscope for the average roughness (Ra). The implant crowns were polished and re-inserted. The results were analyzed using the Kruskal-Wallis test, and post hoc tests were conducted with a significance level of α = 0.05. Significant differences in surface roughness (Ra) were observed between the metallic and non-metallic scalers. The median Ra values were 274.0 nm for metallic scalers and 147.1 nm for non-metallic scalers. However, there were no significant differences between the type of scaler used and the amount of clinical inflammation or cytokine production. Metallic scalers produced deeper, more aggressive surface alterations to the abutment/crown zirconia surface, but there was no statistically significant difference between the degree of surface alterations, amount of BOP, and the amplitude of cytokine inflammation produced.

Association of Periodontitis and Atopic Dermatitis with the Levels of IL-13, IL-31, and TSLP in the Gingival Crevicular Fluid

Emerging epidemiological evidence links atopic dermatitis (AD) and periodontitis, although the mechanisms remain unclear. Th2-derived cytokines are key in the development of both diseases, and different gingival crevicular fluid (GCF) profiles among healthy and diseased subjects have been previously reported. This case-control study examined the GCF levels of interleukins (IL)-13, IL-31, and thymic stromal lymphopoietin (TSLP) in 29 subjects with moderate-to-severe AD and 33 controls. All subjects underwent comprehensive clinical and oral evaluations, followed by GCF collection. GCF levels of IL-13, IL-31, and TSLP were assessed using a multiplex-bead immunoassay. Demographic and periodontal parameters were similar among groups (p > 0.05). The GCF levels of IL-31 and TSLP were higher in AD subjects compared to controls (p < 0.05), whereas no significant differences in the GCF levels of IL-13 were noticed (p = 0.377). Moderate-to-severe AD was positively associated with the GCF levels of IL-31 and TSLP, whereas severe periodontitis was negatively associated with IL-31 (p < 0.05). The GCF levels of IL-13 showed no significant associations with either condition (p = 0.689). There was no significant interaction between AD and periodontitis for IL-31 (p < 0.869). These results suggest that AD and periodontitis independently influence the GCF levels of IL-31 in opposing ways, whereas AD alone influences the levels of TSLP.

Salivary Alterations of Myeloperoxidase in Patients with Systemic Diseases: A Systematic Review

Salivary myeloperoxidase (MPO) is a key mediator of the oral immune system, acting as an enzyme that utilises H2O2 to generate molecules with high bactericidal activity. While MPO determination in plasma is quite common, the use of saliva is still rare. Our systematic review was designed to answer the question "Are salivary levels of myeloperoxidase altered in patients with systemic diseases?". Following the inclusion and exclusion criteria, we included twenty-six studies. Altered MPO levels in saliva were most commonly found in patients with cardiovascular and gastrointestinal diseases. Most studies concerned unstimulated whole saliva, and only a few of them stimulated, mainly by chewing paraffin. Enzyme-linked immunosorbent assay (ELISA) was the most common method for determination of MPO concentrations in saliva. Increased salivary MPO levels were more often observed for inflammatory diseases, except patients with inflammatory bowel diseases who were eligible for biologic therapy. In conclusion, MPO could be altered in the saliva of patients with systematic diseases, especially cardiovascular or gastrointestinal diseases. However, further investigations are recommended to validate these outcomes.

Rapid specific detection of oral bacteria using Cas13-based SHERLOCK

Decades of ongoing research has established that oral microbial communities play a role in oral diseases such as periodontitis and caries. Yet the detection of oral bacteria and the profiling of oral polymicrobial communities currently rely on methods that are costly, slow, and technically complex, such as qPCR or next-generation sequencing. For the widescale screening of oral microorganisms suitable for point-of-care settings, there exists the need for a low-cost, rapid detection technique. Here, we tailored the novel CRISPR-Cas-based assay SHERLOCK for the species-specific detection of oral bacteria. We developed a computational pipeline capable of generating constructs suitable for SHERLOCK and experimentally validated the detection of seven oral bacteria. We achieved detection within the single-molecule range that remained specific in the presence of off-target DNA found within saliva. Further, we adapted the assay for detecting target sequences directly from unprocessed saliva samples. The results of our detection, when tested on 30 healthy human saliva samples, fully aligned with 16S rRNA sequencing. Looking forward, this method of detecting oral bacteria is highly scalable and can be easily optimized for implementation at point-of-care settings.

Influence of periodontitis on levels of autoantibodies in rheumatoid arthritis patients: A systematic review

BACKGROUND AND OBJECTIVE

Periodontitis (PD) is a dysbiotic disease of tooth-supporting structures that has been associated with various systemic diseases including rheumatoid arthritis (RA). To date, evidence demonstrated increased prevalence of RA among PD patients and postulated PD to have a role in the development of autoantibodies in RA patients. Therefore, a systematic review was conducted to assess the available evidence to ascertain the effect of PD on levels of autoantibodies in the serum, saliva and gingival crevicular fluid (GCF) of RA patients.

MATERIAL AND METHODS

The systematic review was conducted in compliance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Relevant literature was searched from PubMed, Web of Science, Scopus and Ebscohost databases from inception until 31 August 2020. The risk of bias in each study was determined based on the Newcastle-Ottawa Scale tool. Results from random-effect meta-analyses were presented as summary estimates of odds ratios (ORs) for seropositivity and standardised mean difference (SMD) of autoantibody levels with 95% confidence intervals. Sensitivity tests and meta-regression were performed to assess the robustness of the results and potential cause of heterogeneity.

RESULTS

The electronic and manual searches gathered 932 articles. Following screening and full-text assessment, a total of 29 studies were included in the analysis. Twenty-eight published observational studies were included in the quantitative analysis in the form of random-effect meta-analysis which revealed that PD was associated with anti-citrullinated proteins autoantibodies (ACPAs) and Rheumatoid Factor (RF) seropositive RA patients (OR for ACPA seropositivity: 1.82; 95% CI: 1.13-2.93) (OR for RF seropositivity: 1.53; 95% CI: 1.05-2.24). Also, RA patients with PD had increased serum levels of ACPA and RF. However, high heterogeneity among studies' results, partially ascribed to the unstandardised case definition of PD and laboratory testing of autoantibodies. Apart from ACPA and RF in serum, studies which reported on other RA-related autoantibodies, as well as autoantibody levels in saliva and GCF were scarce.

CONCLUSION

RA patients with PD tend to have greater ACPA and RF levels in their serum when compared with the RA patients without PD supporting the plausible role of PD in the development of systemic autoimmunity in RA patients.

Potential Impact of Prosthetic Biomaterials on the Periodontium: A Comprehensive Review

The success of a prosthetic treatment is closely related to the periodontal health of the individual. The aim of this article was to review and present the importance of prosthetic restorative materials on the condition of the periodontium, the changes that occur in the composition of the subgingival microbiota and the levels of inflammatory markers in gingival crevicular fluid. Articles on the influence of different prosthetic restorative materials on subgingival microbiota and proinflammatory cytokines were searched for using the keywords "prosthetic biomaterials", "fixed prosthesis", "periodontal health", "subgingival microbiota", "periodontal biomarkers" and "gingival crevicular fluid" in PubMed/Medline, Science Direct, Scopus and Google Scholar. The type of material used for prosthesis fabrication together with poor marginal and internal fit can result in changes in the composition of the subgingival microbiota, as well as increased accumulation and retention of dentobacterial plaque, thus favoring the development of periodontal disease and prosthetic treatment failure. Biological markers have helped to understand the inflammatory response of different prosthetic materials on periodontal tissues with the main purpose of improving their clinical application in patients who need them. Metal-free ceramic prostheses induce a lower inflammatory response regardless of the fabrication method; however, the use of CAD/CAM systems is recommended for their fabrication. In addition, it is presumed that metal-ceramic prostheses cause changes in the composition of the subgingival microbiota producing a more dysbiotic biofilm with a higher prevalence of periodontopathogenic bacteria, which may further favor periodontal deterioration.

Entamoeba gingivalis is associated with periodontal conditions in Chinese young patients: A cross-sectional study

Background

This study investigated the prevalence and relative abundance of Entamoeba gingivalis (E. gingivalis) in Chinese young patients with different periodontal conditions, and its association with subgingival microbial composition, periodontal parameters, and cytokines in gingival crevicular fluid.

Methods

Participants (age: 18–45 years) diagnosed with stage II–IV periodontitis, gingivitis, or periodontal health underwent periodontal examination and sampling. Subgingival plaque was analyzed by 16S+18S sequencing for E. gingivalis detection and microbial analysis. The distribution of E. gingivalis in subgingival plaque was illustrated by fluorescence in situ hybridization. Interleukin-1β, interleukin-8, and tumor necrosis factor-α in gingival crevicular fluid were measured by multiplexed flow cytometric assay.

Results

This cross-sectional study included 120 sites from 60 participants. The prevalence and relative abundance of E. gingivalis were significantly increased in periodontitis (p<0.05). The sites were classified into three subgroups according to the relative abundance of E. gingivalis: negative group (Eg0, n=56); low-abundance group (Eg1, n=32); and high-abundance group (Eg2, n=32). The subgingival microflora in the subgroups showed stepwise changes at both the phylum and genus levels. The microflora compositions were significantly altered from Eg0 to Eg2 (p<0.001). Co-occurrence network analysis showed that Porphyromonas, Treponema, Tannerella, Filifactor, TG5, and Desulfobulbus were highly correlated with E. gingivalis (r>0.6, p<0.001). Correlation analysis showed that E. gingivalis was closely associated with important periodontal parameters and cytokines (p<0.01).

Conclusion

E. gingivalis was enriched in periodontitis and closely associated with subgingival microbial dysbiosis, periodontal parameters and cytokines in gingival crevicular fluid. Thus, it may be an important pathogen in periodontal disease.

Biomarkers in Oral Fluids as Diagnostic Tool for Psoriasis

Psoriasis is a prevalent worldwide chronic immuno-inflammatory skin disease with various variants and atypical cases. The use of biomarkers for the diagnosis of psoriasis can favor timely treatment and thus improve the quality of life of those affected. In general, the search for biomarkers in oral fluids is recommended as it is a non-invasive and fast technique. This narrative review aimed to identify biomarkers in gingival crevicular fluid (GCF) and saliva to diagnose psoriasis. To achieve this goal, we selected the available literature using the following MESH terms: “psoriasis”, “saliva” and “gingival crevicular fluid”. The studies analyzed for this review cover original research articles available in English. We found three full articles available for psoriasis biomarkers in GCF and ten articles available for psoriasis biomarkers in saliva. Studies showed that in the saliva of healthy individuals and those with psoriasis, there were differences in the levels of inflammatory cytokines, immunoglobulin A, and antioxidant biomarkers. In GCF, individuals with psoriasis showed higher levels of S100A8, IL-18 and sE-selectin in comparison to healthy individuals, independent of periodontal status. Despite these findings, more studies are required to determine an adequate panel of biomarkers to use in saliva or GCF for psoriasis.

Phase 2a clinical trial of complement C3 inhibitor AMY-101 in adults with periodontal inflammation

BACKGROUND

Gingivitis and periodontitis are prevalent inflammatory diseases of the periodontal tissues. Current treatments are often ineffective or do not prevent disease recurrence. Uncontrolled complement activation and resulting chronic gingival inflammation is a hallmark of periodontal diseases. We determined efficacy and safety of a complement 3-targeted therapeutic, AMY-101, locally administered in adults with periodontal inflammation.

METHODS

Thirty-two patients with gingival inflammation were enrolled into a randomized, placebo-controlled, double-blind, split-mouth design phase 2a trial, after dose-escalation study to select safe and effective dose with additional 8 patients. Half of the mouth was randomly assigned to AMY-101 (0.1mg/site) or placebo injections at sites of inflammation, administered on days 0, 7 and 14 and evaluated for safety and efficacy outcomes at days 28, 60 and 90. The primary efficacy outcome was change in gingival inflammation, measured by modified gingival index (MGI), and secondary outcomes included changes in bleeding-on-probing (BOP), amount of plaque, pocket depth, clinical attachment level, and gingival crevicular fluid levels of matrix metalloproteinases (MMPs) over 90 days.

RESULTS

A once-per-week intragingival injection of AMY-101 for 3 weeks was safe and well-tolerated in all participants resulting in significant (P<0.001) reductions in clinical indices measuring gingival inflammation (MGI and BOP). AMY-101 significantly (P<0.05) reduced MMP-8 and MMP-9 levels, indicators of inflammatory tissue destruction. These therapeutic effects persisted for at least 3 months post-treatment.

CONCLUSION

AMY-101 causes significant and sustainable reduction in gingival inflammation without adverse events and merits further investigation for the treatment of periodontitis and other oral or peri-implant inflammatory conditions.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03694444.

FUNDING

Amyndas Pharmaceuticals. Amyndas contributed to the design and conducts of the clinical trial and in the writing of the manuscript.

Lyme arthritis: linking infection, inflammation and autoimmunity

Infectious agents can trigger autoimmune responses in a number of chronic inflammatory diseases. Lyme arthritis, which is caused by the tick-transmitted spirochaete Borrelia burgdorferi, is effectively treated in most patients with antibiotic therapy; however, in a subset of patients, arthritis can persist and worsen after the spirochaete has been killed (known as post-infectious Lyme arthritis). This Review details the current understanding of the pathogenetic events in Lyme arthritis, from initial infection in the skin, through infection of the joints, to post-infectious chronic inflammatory arthritis. The central feature of post-infectious Lyme arthritis is an excessive, dysregulated pro-inflammatory immune response during the infection phase that persists into the post-infectious period. This response is characterized by high amounts of IFNγ and inadequate amounts of the anti-inflammatory cytokine IL-10. The consequences of this dysregulated pro-inflammatory response in the synovium include impaired tissue repair, vascular damage, autoimmune and cytotoxic processes, and fibroblast proliferation and fibrosis. These synovial characteristics are similar to those in other chronic inflammatory arthritides, including rheumatoid arthritis. Thus, post-infectious Lyme arthritis provides a model for other chronic autoimmune or autoinflammatory arthritides in which complex immune responses can be triggered and shaped by an infectious agent in concert with host genetic factors.