Clinical periodontal status and inflammatory cytokines in primary Sjögren syndrome and rheumatoid arthritis

Exploration of the shared diagnostic genes and mechanisms between periodontitis and primary Sjögren's syndrome by integrated comprehensive bioinformatics analysis and machine learning

BACKGROUND

Accumulating evidence has showed a bidirectional link between periodontitis (PD) and primary Sjögren's syndrome (pSS), but the mechanisms of their occurrence remain unclear. Hence, this study aimed to investigate the shared diagnostic genes and potential mechanisms between PD and pSS using bioinformatics methods.

METHODS

Gene expression data for PD and pSS were acquired from the Gene Expression Omnibus (GEO) database. Differential expression genes (DEGs) analysis and weighted gene co-expression network analysis (WGCNA) were utilized to search common genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted to explore biological functions. Three machine learning algorithms (least absolute shrinkage and selection operator (LASSO), support vector machine recursive feature elimination (SVM-RFE), and random forest (RF)) were used to further identify shared diagnostic genes, and these genes were assessed via receiver operating characteristic (ROC) curves in discovery and validation datasets. CIBERSORT was employed for immune cell infiltration analysis. Transcription factors (TFs)-genes and miRNAs-genes regulatory networks were conducted by NetworkAnalyst. Finally, relevant drug targets were predicted by DSigDB.

RESULTS

Based on DEGs, 173 overlapping genes were obtained and primarily enriched in immune- and inflammation-related pathways. WGCNA revealed 34 common disease-related genes, which were enriched in similar biological pathways. Intersecting the DEGs with WGCNA results yielded 22 candidate genes. Moreover, three machine learning algorithms identified three shared genes (CSF2RB, CXCR4, and LYN) between PD and pSS, and these genes demonstrated good diagnostic performance (AUC>0.85) in both discovery and validation datasets. The immune cell infiltration analysis showed significant dysregulation in several immune cell populations. Regulatory network analysis highlighted that WRNIP1 and has-mir-155-5p might be pivotal co-regulators of the three shared gene expressions. Finally, the top 10 potential gene-targeted drugs were screened.

CONCLUSION

CSF2RB, CXCR4, and LYN may serve as potential biomarkers for the concurrent diagnosis of PD and pSS. Additionally, we identified common molecular mechanisms, TFs, miRNAs, and candidate drugs between PD and pSS, which may provide novel insights and targets for future research on the pathogenesis, diagnosis, and therapy of both diseases.

Serum transthyretin levels and disease activity in patients with primary Sjögren's syndrome

Background

A strong association has been demonstrated between serum transthyretin (TTR) levels and autoimmune diseases. However, there is limited information regarding the role of serum TTR in patients with primary Sjögren's syndrome (pSS).

Objectives

This study was designed to explore the association between serum TTR and disease activity in patients with pSS.

Design

This study was a retrospective observational study.

Methods

This study included 84 patients with pSS and 135 age- and sex-matched healthy controls retrospectively, and collected data were analyzed. The European League Against Rheumatism (EULAR) Sjögren's Syndrome Disease Activity Index (ESSDAI) and Clinical ESSDAI (ClinESSDAI) scores were used to assess the disease activity in patients with pSS.

Results

Serum TTR levels were significantly lower in patients with pSS than those in healthy controls (181.9 ± 69.2 vs 241.8 ± 48.9 mg/L, p < 0.001). Serum TTR levels were significantly and negatively correlated with ESSDAI (r = -0.385, p < 0.001) and ClinESSDAI (r = -0.340, p = 0.002) scores in patients with pSS, respectively. Multivariable linear regression analysis showed that serum TTR was significantly associated with ESSDAI (Beta = -0.248, p = 0.017) and ClinESSDAI (Beta = -0.215, p = 0.036) scores in patients with pSS, respectively.

Conclusion

Serum TTR is a potential marker for assessing disease activity in patients with pSS, which may contribute to the clinical management of pSS.

Association between Sjögren's Syndrome and Periodontitis: Epidemiological, Fundamental and Clinical Data: A Systematic Review

In recent decades, researchers have investigated the bidirectional links between periodontal disease and systemic diseases, and the results have allowed the development of the concept of periodontal medicine. This concept incorporates and analyzes the mutually influential interactions that can occur between periodontitis and systemic diseases such as diabetes mellitus or cardiovascular diseases. Sjögren's syndrome (SS) is a chronic autoimmune disorder that targets the exocrine glands of the body, such as the lacrimal and salivary glands. The amount of saliva produced may gradually decrease with the progression of the disease, which can have an impact on the structures within the oral cavity. Although the reduction in saliva flow produces negative effects in the oral cavity, a direct association between Sjögren's syndrome and periodontal disease has not yet been demonstrated. Available studies on this topic have not identified significant differences in the periodontal status of patients with Sjögren's syndrome and control groups at the clinical and bacteriological levels. On the other hand, other studies on this topic consider that patients with periodontitis have a higher risk of developing Sjögren's syndrome than the general population. Therefore, the results remain inconclusive, highlighting the need for further complementary studies.

Association of caspase-1 gene polymorphisms with rheumatoid arthritis risk in a Chinese Han population

The goals of present research are to investigate if the genetic polymorphisms in the caspase-1 (CASP1) gene are associated with the risk of rheumatoid arthritis (RA) and the clinical characteristics of the illness in Han patients from China. Our team studied the CASP1 rs2409062 A/G polymorphisms in 1095 healthy controls and 805 RA patients, while the genotype was identified via a custom-by-design 48-Plex single nucleotide polymorphism (SNP) scan™ Kit. The mRNA expression levels of the CASP1 in 40 RA cases and 40 healthy controls were detected by qRT-PCR, while blood plasma levels of the CASP1 in 40 RA cases and 40 paired controls measured via ELISA. Our research showed that the CASP1 rs2409062 A/G polymorphisms were related to an elevated risk for RA. By stratified analysis, our team discovered a remarkably elevated RA risk in females sufferers, age ≥ 55, CRP-positive, or DAS28 < 3.20. In contrast to the control group, the mean level of CASP1 protein in the plasma of RA cases rised significantly. Moreover, RA cases displayed significantly greater levels of CASP1 mRNA versus the control group (P < 0.05). Those outcomes reveal that the CASP1 rs2409062 A/G gene polymorphisms are associated with an elevated risk for RA in a Chinese Han population.

Key Genes of Immunity Associated with Pterygium and Primary Sjögren's Syndrome

Pterygium and primary Sjögren's Syndrome (pSS) share many similarities in clinical symptoms and ocular pathophysiological changes, but their etiology is unclear. To identify the potential genes and pathways related to immunity, two published datasets, GSE2513 containing pterygium information and GSE176510 containing pSS information, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of pterygium or pSS patients compared with healthy control conjunctiva, and the common DEGs between them were analyzed. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted for common DEGs. The protein-protein interaction (PPI) network was constructed using the STRING database to find the hub genes, which were verified in clinical samples. There were 14 co-upregulated DEGs. The GO and KEGG analyses showed that these common DEGs were enriched in pathways correlated with virus infection, antigen processing and presentation, nuclear factor-kappa B (NF-κB) and Th17 cell differentiation. The hub genes (IL1R1, ICAM1, IRAK1, S100A9, and S100A8) were selected by PPI construction. In the era of the COVID-19 epidemic, the relationship between virus infection, vaccination, and the incidence of pSS and pterygium growth deserves more attention.

The association of periodontal diseases and Sjogren's syndrome: A systematic review and meta-analysis

Background

The relationship between periodontal diseases and Sjogren's syndrome were found inconsistent in current studies. Our objective is to clarify the relationship between periodontal diseases and Sjogren's syndrome.

Methods

A systematic review was performed and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic databases (EMBASE, PubMed, Web of Science, and Cochrane Library, from inceptions until 24 November 2021) were searched. The Newcastle-Ottawa Scale (NOS) and Agency for Healthcare Research and Quality (AHRQ) were applied to evaluate the quality of studies. Quality assessment of the certainty of evidence was performed based on the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines. When the output is the ratio, Odds ratio (OR) of periodontal diseases with Sjogren's syndrome were calculated. When the output is the mean, weighted mean difference (WMD) of periodontal diseases with Sjogren's syndrome was calculated. We conducted meta-analysis and estimated the pool sensitivity. Begg's test was used to test the possibility of publication bias. We also carried out meta-regression to clarify the source of heterogeneity (I2 > 50%). Finally, we performed a trial sequential analysis (TSA) to identify the false positive or false negative outcomes that might occur during repeated updates.

Results

21 studies were included in this systematic review, with a total of 11435 subjects. Meta-analysis of 5 studies showed that there is a positive correlation between periodontitis and Sjogren's syndrome (OR = 2.12, 95% CI = 1.43-3.17; 5 studies, 6927 participants; low certainty of evidence). Meta-analysis of 16 studies showed that the periodontal condition of patients with Sjogren's syndrome was worse compared with the control group, and the scores of clinical periodontal parameters were relatively high.

Conclusion

Sjogren's syndrome patients seem to be more likely to be diagnosed with periodontal diseases. However, our results should be interpreted with caution considering the high heterogeneity.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42021261322].

Salivary and serum concentrations of monocyte chemoattractant protein-1, macrophage inhibitory factor, and fractalkine in relation to rheumatoid arthritis and periodontitis

BACKGROUND

Monocyte chemoattractant protein-1 (MCP-1), macrophage migration inhibitory factor (MIF), and fractalkine are chemokines that are expressed by a variety of cell types to regulate macrophage inflammatory response. The aim of the study was to examine the effects of periodontitis and rheumatoid arthritis (RA) on their serum and salivary concentrations.

METHODS

Adults with either periodontitis (P, n = 21), or with rheumatoid arthritis (RA, n = 23), or with both diseases (RA+P, n = 23) were included in the study. Systemically and periodontally healthy individuals (n = 22) served as controls. Saliva and serum samples were collected from all participants before the medical and periodontal examinations. Salivary and serum MCP-1, MIF, and fractalkine concentrations were measured by the Luminex technique. Total salivary protein levels were determined by the Bradford assay.

RESULTS

Salivary MCP-1, MIF, and fractalkine concentrations were elevated in both RA groups (RA+P and RA) in comparison with systemically healthy controls. As related to total salivary protein levels, higher MCP-1 (P = 0.003) and fractalkine (P = 0.045) concentrations were found in controls compared with the P group. In serum, MCP-1 concentrations in the RA+P group were higher (P = 0.003) than those of group P. Elevated serum fractalkine concentrations were observed in both periodontitis groups (RA+P, P = 0.014; and P, P = 0.013) compared with controls.

CONCLUSIONS

In RA, MCP-1, MIF, and fractalkine concentrations are elevated in saliva. These chemokines may disrupt oral macrophage responses and potentially take part in the interaction between periodontitis and RA.

Cytokines in gingivocrevicular fluid of rheumatoid arthritis patients: A review of the literature

OBJECTIVE

Rheumatoid arthritis (RA) and periodontitis share several pathological features including bone and soft tissue destruction and high levels of circulating inflammatory proteins. Studies related to cytokines in the periodontal inflammatory exudate (gingivocrevicular fluid, GCF) of RA patients might provide insight into the association between periodontitis and RA. The aim of our study was to review the literature on cytokines in GCF of RA patients including the effect of anti-rheumatic treatment with biological disease-modifying anti-rheumatic drugs (DMARDs) and periodontal treatment on these cytokines.

MATERIALS AND METHODS

MedLine/PubMed searches with different combinations of keywords "rheumatoid arthritis or RA" and "crevicular fluid or GCF" until June 2019 revealed 64 articles. Ten cross-sectional observational studies and nine treatment studies fulfilled the inclusion criteria.

RESULTS

Rheumatoid arthritis patients have increased circulating and GCF levels of pro-inflammatory cytokines and proteins, despite anti-rheumatic treatment with biological DMARDs. Presence of periodontitis was accompanied by higher cytokine and protein levels. Treatment of periodontitis resulted in a decrease of these levels.

CONCLUSION

Analysis of GCF of RA patients reveals that the relationship between periodontitis and RA is bidirectional, probably caused by a non-specific inflammatory burden. Data for a specific relationship are barely present in GCF.

Increased expression of caspase 1 during active phase of connective tissue disease

Key factors of pyroptosis play an important role in the inflammatory response to connective tissue disease (CTD). However, information on active and stable stages of CTD is scarce. To distinguish the differences of concentrations of C-reactive protein (CRP), caspase 1, caspase 4, caspase 5 and sCD14 in plasma between the patients with active and stable stages of CTD. A cohort study was conducted to recruit patients diagnosed with CTD of active phase and stable phase as well as health control. These data included the analysis of the concentration of sCD14, caspase 1, caspase 4 and caspase 5 in peripheral plasma by ELISA. The Wilcoxon rank-sum test was used to compare the two groups. The sex ratio and ages of the three groups were not different statistically. The concentrations of sCD14, caspase4 and caspase5 of plasma in the CTD of active phase and the stable phase as well as the health control. The concentration of caspase 1 in active phase of CTD (470.19 [422.33–513.14] pmol/L) was significantly higher than that in stable group (203.95 [160.94–236.12] pmol/L) and healthy control (201.65 [191.11–240.35] pmol/L] pmol/L) (p < 0.001, both), but there was no significant difference between stable group and healthy control (p = 0.2312). Similarly, the concentration of CRP in the active phase of CTD (8.96 [3.06–20.28] mg/L) was significantly higher than that in the stable group (3.00 [1.30–11.40] mg/L) and the healthy control (3.70 [2.30–4.73] mg/L) (p = 0.0013, p = 0.0006, respectively), but there was no significant difference between the stable group and the healthy control (p = 0.3205). However, there were no significant differences in the concentration of sCD14, caspase 4 and caspase 5 in the active phase of CTD and the stable group as well as the health group. Consequently, the patients of the active phase of CTD showed increased expression of caspase 1.

Main Oral Manifestations in Immune-Mediated and Inflammatory Rheumatic Diseases

Oral manifestations are frequent in patients with rheumatic diseases. The aim of this review is to offer readers practical advice concerning the onset, diagnosis and treatment of the main oral manifestations encountered in rheumatological and dental clinics. Signs and symptoms such as oral hyposalivation, xerostomia, temporomandibular joint disorders, periodontal disease, and dysphagia may be the first expression of a number of rheumatic diseases. Some of these manifestations are aspecific and very frequent, such as oral aphthosis, which can be the first manifestation in patients with systemic lupus erythematosus; some are potentially dangerous, such as jaw claudication during the course of giant cell arteritis; and some are very rare but peculiar, such as strawberry-like gingivitis in patients with granulomatosis with polyangiitis. Other oral manifestations are due to adverse reactions to disease-modifying anti-rheumatic drugs. Oral alterations in rheumatic diseases are frequently overlooked in clinical practice, but their prompt recognition not only allows the local lesions to be appropriately treated, but also makes it possible to identify an underlying systemic disease.