A prospective study of periodontal disease and risk of rheumatoid arthritis

Exploring the Bidirectional Relationship Between Periodontitis and Rheumatoid Arthritis in a Large Danish Cohort

OBJECTIVE

We investigated the bidirectional relationship between rheumatoid arthritis (RA) and periodontitis and their cross-sectional association using national administrative health care data.

METHODS

The sample included 3,308,903 individuals aged 20 to 79 years who resided in Denmark in 2000 and had remained free of RA and periodontitis in the previous 10 years. RA and periodontitis were defined using diagnosis and treatment codes. Marginal structural survival models were employed to estimate the effects of RA on periodontitis incidence and vice versa from 2000 to 2017. Using a cross-sectional sample of 2,574,536 individuals from 2017, the association of periodontitis with RA was investigated using regression analyses and probabilistic quantitative bias analyses, simulating RA and periodontitis misclassification and unmeasured confounding of smoking.

RESULTS

Between 2000 and 2017, 20,348 individuals developed RA and 740,799 developed periodontitis. The estimated hazard ratio (HR) for the effect of periodontitis on incident RA was 1.05 (95% confidence interval [CI] 0.88-1.25), resulting in a restricted mean survival time difference of one day. The HR for the effect of RA on incident periodontitis was 0.84 (95% CI 0.80-0.88), corresponding to a restricted mean survival time difference of 151 days. Cross-sectionally, the unadjusted prevalence ratio for the association was 1.15 (95% CI 1.11-1.19), whereas the estimate adjusted for measured and simulated confounding was practically null (0.99, 95% simulation interval 0.93-1.04).

CONCLUSION

These findings challenge previously reported bidirectional relationships between periodontitis and RA, pointing to potential residual confounding as an important link and prompting reconsideration of the biologic plausibility and clinical significance of these associations.

The Impact of Rheumatoid Arthritis on First Nations and How We Can Work With Communities to Prevent It

Rheumatoid arthritis (RA) is prevalent in many Indigenous North American First Nations (FN) and tends to be seropositive, familial, and disabling, as well as associated with highly unfavorable outcomes such as early mortality. The risk of developing RA is based on a perfect storm of gene-environment interactions underpinning this risk. The gene-environment interactions include a high frequency of shared epitope encoding HLA alleles, particularly HLA-DRB1*1402, in the background population, and prevalent predisposing environmental factors such as smoking and periodontal disease. Together, these provide a compelling rationale for an RA prevention agenda in FN communities. Our research team has worked in partnership with several FN communities to prospectively follow the first-degree relatives of FN patients with RA, with the aim of better understanding the preclinical stages of RA in this population. We have focused on specific features of the anticitrullinated protein antibodies (ACPA) and other proteomic biomarkers as predictors of future development of RA. These studies have now led us to consider interventions having a favorable risk-benefit ratio if applied at a stage prior to a hypothetical "point of no return," when the autoimmunity potentially becomes irreversible. Based on a supportive mouse model and available human studies of curcumin, omega-3, and vitamin D supplements, we are undertaking studies where we screen communities using dried blood spot technology adapted for the detection of ACPA, and then enrolling ACPA-positive individuals in studies that use a combination of these supplements. These studies are guided by shared decision-making principles.

The Association of Chronic Periodontitis as a Potential Risk Factor with Rheumatoid Arthritis: A Nested Case-Control Study Using a Korean National Health Screening Cohort

Growing research has proposed that rheumatoid arthritis (RA) and chronic periodontitis (CP) share similar pathophysiological mechanisms involving inflammation and tissue destruction. However, the potential correlation of CP as a contributing factor for the occurrence of RA warrants validation in the Korean population, where both diseases are prevalent, especially considering the increasingly aging demographic in Korea. This study examined 5139 RA cases and 509,727 matched controls from a Korean national cohort dataset (2002-2019) by carefully employing propensity score matching to ensure comparability between groups. Baseline characteristics were compared using standardized differences, and logistic regression was employed to estimate the impact of CP history on RA likelihood while controlling for covariates. We fully examined medical records documenting CP occurrences within the two-year period leading up to the index date, conducting comprehensive subgroup analyses. While a 1-year history of CP did not show a significant association with likelihood of RA, a 2-year history of CP increased RA likelihood by 12%, particularly among older adults, females, rural residents, and those with certain comorbidities such as hypercholesterolemia. Interestingly, this association persisted even among individuals with non-smoking habits, normal weight, and infrequent alcohol consumption. These findings suggest that chronic CP exposure for at least 2 years may independently elevate RA risk in Korean adults. The association in certain subgroups appears to suggest a predisposition toward genetic susceptibilities over lifestyle and environmental factors. Predicting RA in CP patients may be challenging, emphasizing the importance of regular RA screening, especially in high-risk subgroups.

Periodontitis and risk of immune-mediated systemic conditions: A systematic review and meta-analysis

INTRODUCTION

The aim of this review is to examine and quantify the long-term risk of immune-mediated systemic conditions in people with periodontitis compared to people without periodontitis.

METHODS

Medline, EMBASE and Cochrane databases were searched up to June 2022 using keywords and MeSH headings. The 'Risk of Bias in Non-Randomised Studies of Interventions' tool was used to assess bias. Cohort studies comparing incident metabolic/autoimmune/inflammatory diseases in periodontitis to healthy controls were included. Meta-analysis and meta-regression quantified risks and showed impact of periodontitis diagnosis type and severity.

RESULTS

The search retrieved 3354 studies; 166 studies were eligible for full-text screening, and 30 studies were included for review. Twenty-seven studies were eligible for meta-analysis. The risks of diabetes, rheumatoid arthritis (RA) and osteoporosis were increased in people with periodontitis compared to without periodontitis (diabetes-relative risk [RR]: 1.22, 95% CI: 1.13-1.33; RA-RR: 1.27, 95% CI: 1.07-1.52; osteoporosis-RR: 1.40, 95% CI: 1.12-1.75). Risk of diabetes showed gradient increase by periodontitis severity (moderate-RR = 1.20, 95% CI = 1.11-1.31; severe-RR = 1.34, 95% CI = 1.10-1.63).

CONCLUSION

People with moderate-to-severe cases of periodontitis have the highest risk of developing diabetes, while the effect of periodontal severity on risk of other immune-mediated systemic conditions requires further investigation. More homologous evidence is required to form robust conclusions regarding periodontitis-multimorbidity associations.

Differential associations of rheumatoid arthritis and periodontitis or tooth loss: A cross-sectional study

AIM

To study the association between periodontitis, tooth loss, and rheumatoid arthritis (RA) by using a large national dataset.

MATERIALS AND METHODS

An observational cross-sectional study was performed using the National Health and Nutrition Examination Survey cycles (2009-2014). RA status was detected using a questionnaire. Periodontal status was assigned on the basis of the clinical attachment level and periodontal pocket depth. Dentition status was assessed by the number of permanent teeth observed. We examined the association between RA as exposure and moderate/severe periodontitis and non-functional dentition as outcomes. We progressively adjusted our models for different sets of potential confounders.

RESULTS

Moderate/severe periodontitis was more prevalent in participants reporting RA (53% vs. 41.5%, p = .0003). Non-functional dentition was more prevalent in participants with RA (41% vs. 15.5%, p = .0001). The fully adjusted model showed that participants with RA had higher odds of having non-functional dentition (odds ratio 1.8, 95% confidence interval [CI] 1.3-2.3, p = .0001) but no association with moderate/severe periodontitis (prevalence ratio 1.01, 95% CI 0.9-1.1, p = .9).

CONCLUSION

RA was associated with a higher likelihood of having non-functional dentition but did not show any association with periodontitis after adjusting for the risk factors to control their confounding effect.

Association of Oral Health with Risk of Rheumatoid Arthritis: A Nationwide Cohort Study

Periodontitis and rheumatoid arthritis (RA) are inflammatory diseases that share many similarities. We aimed to investigate the associations of periodontitis and oral hygiene status and behaviors with RA in a nationwide general population cohort. Participants from the National Health Screening cohort database of Korea who underwent oral health screening by dentists between 2003 and 2004 were included. The occurrence of RA was analyzed according to the presence of periodontitis, oral health examination findings, and behaviors. Overall, 2,239,586 participants were included. During a median of 16.7 years, RA occurred in 27,029 (1.2%) participants. The risk for incident RA was higher when participants had periodontitis (hazard ratio (HR) 1.2, 95% confidence interval (CI), 1.08-1.24) and an increased number of missing teeth (HR 1.5, 95% CI, 1.38-1.69). In contrast, better oral hygiene behaviors, such as a higher frequency of daily tooth brushing (HR 0.76, 95% CI 0.73-0.79, p for trend <0.001) and a recent history of dental scaling (HR 0.96, 95% CI 0.94-0.99), were associated with a lower occurrence of RA. Periodontitis and increased missing teeth were associated with an increased risk of RA. Maintaining good oral hygiene through frequent tooth brushing and regular dental scaling may reduce the risk of RA occurrence.

Disease mechanisms in preclinical rheumatoid arthritis: A narrative review

In the last decades, the concept of preclinical rheumatoid arthritis (RA) has become established. In fact, the discovery that disease mechanisms start years before the onset of clinical RA has been one of the major recent insights in the understanding of RA pathogenesis. In accordance with the complex nature of the disease, preclinical events extend over several sequential phases. In a genetically predisposed host, environmental factors will further increase susceptibility for incident RA. In the initial steps of preclinical disease, immune disturbance mechanisms take place outside the joint compartment, namely in mucosal surfaces, such as the lung, gums or gut. Herein, the persistent immunologic response to altered antigens will lead to breach of tolerance and trigger autoimmunity. In a second phase, the immune response matures and is amplified at a systemic level, with epitope spreading and widening of the autoantibody repertoire. Finally, the synovial and bone compartment are targeted by specific autoantibodies against modified antigens, initiating a local inflammatory response that will eventually culminate in clinically evident synovitis. In this review, we discuss the elaborate disease mechanisms in place during preclinical RA, providing a broad perspective in the light of current evidence.

No Genetic Causal Association Between Periodontitis and Arthritis: A Bidirectional Two-Sample Mendelian Randomization Analysis

Objectives

Periodontitis (PD) has been linked to arthritis in previous epidemiological observational studies; however, the results are inconclusive. It remains unclear whether the association between PD and arthritis is causal. The purpose of this study was to investigate the causal association of PD with arthritis, including rheumatoid arthritis (RA) and osteoarthritis (OA).

Methods

We performed a two-sample bidirectional Mendelian randomization (MR) analysis using publicly released genome-wide association studies (GWAS) statistics. The inverse-variance weighted (IVW) method was used as the primary analysis. We applied four complementary methods, including weighted median, weighted mode, MR-Egger regression and MR pleiotropy residual sum and outlier (MR-PRESSO) to detect and correct for the effect of horizontal pleiotropy.

Results

Genetically determined PD did not have a causal effect on OA (OR = 1.06, 95% CI: 0.99-1.15, P = 0.09) and RA (OR = 0.99, 95% CI: 0.87-1.13, P = 0.89). Furthermore, we did not find a significant causal effect of arthritis on PD in the reverse MR analysis. The results of MR-Egger regression, Weighted Median, and Weighted Mode methods were consistent with those of the IVW method. Horizontal pleiotropy was unlikely to distort the causal estimates according to the sensitivity analysis.

Conclusions

Our MR analysis reveals non-causal association of PD with arthritis, despite observational studies reporting an association between PD and arthritis.

Etiology and Risk Factors for Rheumatoid Arthritis: A State-of-the-Art Review

Rheumatoid arthritis (RA) is the most common systemic inflammatory rheumatic disease. It is associated with significant burden at the patient and societal level. Extensive efforts have been devoted to identifying a potential cause for the development of RA. Epidemiological studies have thoroughly investigated the association of several factors with the risk and course of RA. Although a precise etiology remains elusive, the current understanding is that RA is a multifactorial disease, wherein complex interactions between host and environmental factors determine the overall risk of disease susceptibility, persistence and severity. Risk factors related to the host that have been associated with RA development may be divided into genetic; epigenetic; hormonal, reproductive and neuroendocrine; and comorbid host factors. In turn, environmental risk factors include smoking and other airborne exposures; microbiota and infectious agents; diet; and socioeconomic factors. In the present narrative review, aimed at clinicians and researchers in the field of RA, we provide a state-of-the-art overview of the current knowledge on this topic, focusing on recent progresses that have improved our comprehension of disease risk and development.

The Effect of Acknowledged and Novel Anti-Rheumatic Therapies on Periodontal Tissues-A Narrative Review

Rheumatoid arthritis (RA) and periodontal disease (PD) are chronic complex inflammatory diseases with several common susceptibility factors, especially genetic and environmental risk factors. Although both disorders involve a perturbation of the immune-inflammatory response at multiple levels, one major difference between the two is the different locations in which they develop. RA is triggered by an exaggerated autoimmune response that targets joints, while periodontal disease occurs as a consequence of the subgingival periodontopathogenic microbiota. Current treatment models in both pathologies involve the stratification of patients to allow therapeutic individualization according to disease stage, complexity, progression, lifestyle, risk factors, and additional systemic diseases. Therapeutic guidelines for RA comprise of five main classes of drugs: non-steroidal anti-inflammatory drugs (NSAIDs), analgesics, glucocorticoids, and disease-modifying anti-rheumatic drugs (DMARDs): biologic and non-biologic. Although various treatment options are available, a definitive treatment remains elusive, therefore research is ongoing in this area. Several alternatives are currently being tested, such as matrix metalloproteinases (MMP) inhibitors, toll-like receptors (TLR) blockers, pro-resolution mediators, anti-hypoxia inducing factors, stem cell therapy, NLRP3 inhibitors and even natural derived compounds. Although the link between PD and rheumatoid arthritis has been investigated by multiple microbiology and immunology studies, the precise influence and causality is still debated in the literature. Furthermore, the immunomodulatory effect of anti-rheumatic drugs on the periodontium is still largely unknown. In this narrative review, we explore the mechanisms of interaction and the potential influence that anti-rheumatoid medication, including novel treatment options, has on periodontal tissues and whether periodontal health status and treatment can improve the prognosis of an RA patient.

Association between rheumatoid arthritis and periodontitis in an adult population - A cross sectional study

Background

This investigation was aimed to analyse the existence of an association between rheumatoid arthritis and periodontitis among Indian subjects.

Material and Methods

This observational study included a total of 110 individuals between 18-78 years of age, which were divided equally into RA (Rheumatoid Arthritis) and NRA (Non-Rheumatoid Arthritis) groups. General, Oral and a complete Periodontal examination included recording of Gingival Index (GI), Plaque index (PI), Pocket Probing Depth (PPD), Clinical attachment level (CAL) in a questionnaire form. Laboratory and rheumatologcal parameters like C-reactive protein (CRP), Erythrocyte sedimentation rate (ESR) and Disease Activity Score 28(DAS 28), Health Assessment Questionnaire–Disability Index (HAQ), Rheumatoid factor (RF) were also respectively estimated.

Results

Prevalence of moderate or severe periodontitis was higher in RA than in NRA group. (41.8% vs 23.6%, p= 0.047). Periodontal structural damage represented by clinical attachment level was more in RA patients (2.89 mm v/s 2.54mm, p=0.261). Mean score of HAQ was co-related significantly in patients with CAL ≥ 2mm than with CAL < 2mm (0.69 v/s 0.455, p=0.0415). Through logistic regression analysis, periodontitis and CAL were related to RA with OR (Odds Ratio) of 2.1 and 2.89 respectively.

Conclusions

Indian RA patients have higher odds for periodontitis and CAL may act as a risk indicator for RA.

Key words:Chronic periodontitis, rheumatoid arthritis, disease activity score 28, health assessment questionnaire, rheumatoid factor, c-reactive protein , erythrocyte sedimentation rate.

Rheumatoid arthritis associated with the occurrence, severity and extension of periodontitis: A case-control study

Background

Emerging evidence pointed to a potential association between periodontitis (PE) and rheumatoid arthritis (RA), based on shared characteristics and similarities in risk factors, immunogenetics and pathways of tissue destruction. The aim of this study was to evaluate the potential association between RA and PE, as well as the influence of risk variables in this association.

Material and Methods

The present case-control study comprised 471 individuals (157 cases with RA and 314 controls) that underwent a full-mouth periodontal examination. The association between risk variables and the occurrence of AR and PE were evaluated through univariate and multivariate logistic analysis.

Results

Higher frequency (p<0.001), severity (p=0.006) and extension (p=0.018) of PE was observed among the cases when compared to controls. Variables retained in the final multivariate models for the occurrence of PE were: lower number of teeth, smoking, no use of dental floss, ≥4 daily toothbrushing and RA; for the occurrence of RA were: higher age, female gender, smoking, alcohol use and PE. It is important to stress that RA (OR=2.53; 95%CI 1.24-3.86; p<0.001) was retained in the model for PE, and PE (OR=3.12; 95%CI 1.47-4.26; p<0.001) was retained in the model for RA.

Conclusions

The present study demonstrated a high frequency of PE among individuals with RA and an important association among the occurrence, severity and extension of PE and RA and smoking. Key words:Case-control study, risk factors, periodontitis, rheumatoid arthritis.

Periodontitis as a risk factor for rheumatoid arthritis: a matched-cohort study

OBJECTIVE

The intent was to analyse the association of periodontitis with the development of rheumatoid arthritis (RA) using a representative population-based cohort and longitudinal matched-cohort design.

METHODS

Participants were 40 years of age or older and had not been diagnosed with RA between 2002 and 2006. Among the participants, those who were newly diagnosed with periodontitis between 2004 and 2006 (excluding cases that had already been diagnosed with periodontitis between 2002 and 2003) were allotted to the periodontitis group. Among the participants, those who had never been diagnosed with periodontitis between 2002 and 2006 formed the control group, matched by sex, age, and household income at a 1:1 ratio. From 2007 to 2018, the 2 groups (n = 691,506) were followed to monitor the development of RA. The t-test and χ² test compared the general characteristics and health-related variables of both groups. The Kaplan-Meier method with a log-rank test was conducted to compare the incidence of RA in both groups. The hazard ratio (HR) and adjusted hazard ratio (aHR) were calculated using a Cox proportional hazard regression analysis to evaluate the risk of subsequent RA.

RESULTS

Univariate analysis revealed that the periodontitis group was more likely to develop RA than the control group (hazard ratio 1.10), and multivariate analysis also revealed a higher incidence risk of RA (adjusted hazard ratio 1.09) in the periodontitis group.

CONCLUSIONS

Our findings demonstrate that periodontitis is associated with an increased risk of developing RA.

Investigating the relationship between the severity of periodontitis and rheumatoid arthritis: a cross-sectional study

OBJECTIVES

This paper evaluates the prevalence and severity of periodontitis (PD) in patients with rheumatoid arthritis (RA), focusing on the link between the severity of PD with RA disease activity/disability scores, the influence of RA treatment on PD, and levels of vitamin D.

METHODS

A total of 93 RA patients were enrolled in the cross-sectional study and analyzed accordingly as RA-PD (N = 63, 67.8%) and RA-only (N = 30, 32.2%) groups. A number of associations between rheumatological clinical data, i.e., Disease Activity Score (DAS28 CRP), health assessment questionnaires, and PD severity (measured by periodontal outcome parameters) with regard to serum levels of vitamin D were assessed. The outcome variables were compared by parametric and non-parametric tests.

RESULTS

A total of 29% of RA patients were diagnosed with severe PD. The RA-PD group presented a higher mean DAS28 CRP score in moderate-severe PD compared to periodontally healthy-initial stage PD subjects (4.49 ± 1.22 vs. 3.86 ± 1.58, p = 0.033). RA patients treated with biologic disease-modifying antirheumatic drugs (bDMARDs) were less likely to be diagnosed with PD (p = 0.022) and revealed significantly lower PD outcome parameters, i.e., bleeding on probing (%) and bone loss (%) (p < 0.05). Vitamin D concentration was significantly lower in RA-PD group with diagnosed advanced severe PD (IV stage) compared to moderate PD (II stage) (39.61 ± 17.12 vs. 52.07 ± 18.23 nmol/l, p = 0.031).

CONCLUSIONS

The study revealed a high prevalence of severe PD in RA patients, being significantly associated with higher RA disease activity and lower vitamin D level in RA-PD group, while bDMARD treatment was related to lower PD outcome parameters. Key Points • Severe PD is prevalent amongst RA patients and is associated with RA disease activity. The higher RA DAS28 CRP score is associated with moderate-severe PD compared to periodontally healthy-initial stage PD in RA patients. • Biologic DMARDs treatment used for RA is linked to lower PD rates and PD outcome parameters. • Significantly lower vitamin D level is found in advanced severe PD compared to moderate PD stage in RA-PD subjects.

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

BACKGROUND

The association of periodontitis and Porphyromonas gingivalis (Pg) with rheumatoid arthritis (RA) is incompletely understood. To gain further insights, we evaluated periodontal status, oral, serum and joint inflammatory profiles, and Pg biomarkers in RA patients.

METHODS

In this cross-sectional study, we evaluated 33 patients with predominantly untreated new-onset RA, 20 healthy individuals (HIs), and 20 non-RA chronic periodontitis patients. Thirteen mediators (IFN-γ, IL-10, IL-17A, IL-6, IL-8, CXCL10, TNF-α, CXCL13, IL-23, MMP-1, MMP-3, MMP-8, MMP-9) were measured in serum, synovial fluid, saliva and gingival crevicular fluid (GCF) by multiplex immunoassay. Serum Pg IgG antibodies and subgingival Pg DNA were determined.

RESULTS

Most RA patients (91%) received routine dental care; only one currently smoked. Ten (30.3%) had periodontal health, 13 (39.4%) had gingivitis, and 10 (30.3%) had periodontitis. Th1 and innate immune responses predominated in serum. Many mediators were concentrated in joints, particularly IL-6, IL-8, and CXCL10. However, salivary and GCF profiles were more restricted, emphasizing neutrophilic inflammation (IL-8, MMP-8) and MMP-9. Compared with HI, most RA patients, regardless of periodontal status, had significantly elevated oral fluid levels of these mediators, with suppression of GCF IL-10, a pattern similar to non-RA periodontitis patients. Pg antibodies or DNA however were primarily associated with clinical periodontitis.

CONCLUSIONS

Despite routine dental care, RA patients often had inflammation in oral fluids, but inflammatory profiles differed from serum and joints. Neutrophilic inflammatory profiles in oral fluids, regardless of periodontal status, suggests that gingival tissues are a common, and often unrecognized, site of extra-articular inflammation in RA.

Streptococcus species enriched in the oral cavity of patients with RA are a source of peptidoglycan-polysaccharide polymers that can induce arthritis in mice

OBJECTIVES

Analysis of oral dysbiosis in individuals sharing genetic and environmental risk factors with rheumatoid arthritis (RA) patients may illuminate how microbiota contribute to disease susceptibility. We studied the oral microbiota in a prospective cohort of patients with RA, first-degree relatives (FDR) and healthy controls (HC), then genomically and functionally characterised streptococcal species from each group to understand their potential contribution to RA development.

METHODS

After DNA extraction from tongue swabs, targeted 16S rRNA gene sequencing and statistical analysis, we defined a microbial dysbiosis score based on an operational taxonomic unit signature of disease. After selective culture from swabs, we identified streptococci by sequencing. We examined the ability of streptococcal cell walls (SCW) from isolates to induce cytokines from splenocytes and arthritis in ZAP-70-mutant SKG mice.

RESULTS

RA and FDR were more likely to have periodontitis symptoms. An oral microbial dysbiosis score discriminated RA and HC subjects and predicted similarity of FDR to RA. Streptococcaceae were major contributors to the score. We identified 10 out of 15 streptococcal isolates as S. parasalivarius sp. nov., a distinct sister species to S. salivarius. Tumour necrosis factor and interleukin 6 production in vitro differed in response to individual S. parasalivarius isolates, suggesting strain specific effects on innate immunity. Cytokine secretion was associated with the presence of proteins potentially involved in S. parasalivarius SCW synthesis. Systemic administration of SCW from RA and HC-associated S. parasalivarius strains induced similar chronic arthritis.

CONCLUSIONS

Dysbiosis-associated periodontal inflammation and barrier dysfunction may permit arthritogenic insoluble pro-inflammatory pathogen-associated molecules, like SCW, to reach synovial tissue.

Clinical and microbiological effects of non-surgical periodontal treatment in individuals with rheumatoid arthritis: a controlled clinical trial

The effect of periodontal treatment on clinical, microbiological and serological parameters of patients with rheumatoid arthritis (RA) are scarce and controversial. The aim of this study was to investigate the influence of non-surgical periodontal treatment on clinical periodontal status, subgingival bacterial levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola and RA activity through a controlled clinical trial on individuals with RA and periodontitis (PE). From a convenience sample, 107 individuals were considered eligible and consecutively allocated in four groups: (1) individuals without PE and RA (- PE-RA, n = 30); (2) individuals without PE and with RA (- PE + RA, n = 23); (3) individuals with PE and RA (+ PE + RA, n = 24); and (4) individuals with PE and without RA (+ PE-RA, n = 30). Full-mouth periodontal clinical examinations, microbiological analysis and Disease Activity Score (DAS-28) evaluations were performed at baseline (T1) and 45 days after non-surgical periodontal treatment (T2). At T1, individuals + PE + RA showed greater severity of PE than + PE-RA individuals. At T2, significant reductions were observed in all periodontal clinical parameters in both groups (p < 0.001) with a significant reduction in DAS-28 in + PE + RA (p = 0.011). Individuals + PE-RA and + PE-RA showed significant reductions for all bacteria (p < 0.001). Additionally, P. gingivalis demonstrated an expressively significant reduction in + PE + RA (p < 0.001). Non-surgical periodontal treatment was effective on improving the clinical periodontal condition, improving the RA clinical status and reducing the presence of periodontal pathogens. Brazilian Registry of Clinical Trials (ReBEC) protocol #RBR-8g2bc8 ( https://www.ensaiosclinicos.gov.br/rg/RBR-8g2bc8/ ).

Electroacupuncture Reduces Inflammation but Not Bone Loss on Periodontitis in Arthritic Rats

Periodontitis and rheumatoid arthritis (RA) are inflammatory diseases characterized by chronic inflammation and bone erosion. Electroacupuncture (EA) shows anti-inflammatory and anti-resorptive effects in experimental periodontitis (EP) and in RA. It is important to investigate whether EA shows these effects in periodontal tissues in the presence of these two inflammatory diseases or not. For this, Wistar rats were divided into six groups: control (C); experimental rheumatoid arthritis (RA; bovine type II collagen-induced (CII)); experimental periodontitis (EP); RA/EP (RA + EP); EP/EA (EP treated with EA); RA/EP/EA (RA + EP treated with EA). EP was induced 21 days after RA induction and EA was performed previously and during the EP induction period, every 3 days until the 36th experimental day. The rats were euthanized on day 39. RA was evaluated by edema and the withdrawal threshold of hind paws. The maxillae were removed, and alveolar bone loss (ABL) and bone radiographic density (BRD) were evaluated. Immunohistochemical analyses for interleukins (IL)-6 and -17 and nuclear factor (NF)-κB were performed. Our results showed that EA reduced only the pain intensity in arthritic rats. Histomorphometric, macroscopic, and radiographic analyses did not show differences between the control and EP/EA groups. EA caused a reduction in ABL and BRD only in the presence of EP. EA caused a reduction in IL-6 and -17 in all groups, but NF-κB was only reduced in the arthritic rats with EP. In conclusion, EA reduced the inflammation related to periodontitis in arthritic rats but did not prevent ABL.

Rheumatoid arthritis risk in periodontitis patients: A systematic review and meta-analysis

OBJECTIVE

Many clinical studies have been carried out to investigate the relationship between periodontitis and rheumatoid arthritis (RA). Owing to limited evidence and inconsistent findings among these studies, it is unclear whether periodontitis would increase the risk for RA. This meta-analysis was performed to evaluate whether periodontitis represents a risk factor for RA.

METHODS

PubMed, Cochrane Library, Embase, Web of Science, and Wanfang were searched for eligible studies that compared periodontitis patients with controls. A pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to assess the association between periodontitis and RA.

RESULTS

Thirteen studies including a total of 706611 periodontitis patients and 349983 control subjects were included. The pooled OR of RA risk between periodontitis and controls was (OR: 1.69; 95% CI: 1.31-2.17; P<0.0001), indicating that the patients in periodontitis group had a 69% greater risk for RA than people in control group. When stratified by disease type, the pooled results showed periodontitis represents a risk factor for incident RA (OR=1.70, 95%CI: 0.75-3.85, P<0.001) and mixed RA (OR=1.61, 95%CI: 1.26-2.06; P<0.001). When stratified by disease duration, the pooled results showed periodontitis represents a risk factor for RA disease duration>5 years (OR=2.88, 95%CI: 0.66-12.62, P=0.018), disease duration<5 years (OR=2.59, 95%CI: 0.83-8.11, P<0.001), mixed disease duration (OR=1.53; 95%CI: 1.05-2.22, P<0.001).

CONCLUSION

Our meta-analysis revealed an increased risk of RA in patients with periodontitis compared to healthy controls. Moreover, when stratified by disease type, there was a higher risk between incident RA and periodontitis. When stratified by disease duration, the patients with periodontitis might be more closely associated with the RA patients with disease duration >5 years.

Temporomandibular joint function, periodontal health, and oral microbiome in early rheumatoid arthritis and at-risk individuals: a prospective cohort study protocol

Objectives/aims

Rheumatoid arthritis (RA) is an autoimmune disease affecting the joints, including the temporomandibular joint (TMJ). Early diagnosis and treatment can alleviate symptoms and prevent progression. Predictors for disease outcome in individuals at risk for RA are therefore valuable. While limited information is available on the prevalence of TMJ involvement in early RA, previous studies suggest that RA, periodontitis and the oral microbiome are interrelated. Predictive factors for RA development may thus be present in the oral cavity. Our two aims are: (1) to assess the prevalence of TMJ involvement in early RA, and (2) to investigate the predictive value of oral factors in RA development.

Materials and methods

We will include 150 individuals in this multi-center, prospective cohort study: 50 patients with early RA, 50 at-risk individuals, and 50 healthy controls. At baseline, the TMJ, periodontal health, and the oral microbiome will be examined. The general health will be followed over time, on four occasions up to 3 years.

Discussion

Our results will provide insight into the prevalence and clinical characterization of TMJ involvement in early RA. For at-risk individuals, oral factors can be studied as possible predictors for the development of RA.

The microbiome and rheumatoid arthritis

Rheumatoid Arthritis (RA) is a severe, chronic autoimmune disease that affects 1% of the world's population. Familial risk contributes 50% of the risk of seropositive RA, with strongest risks seen in first-degree relatives. Smoking increases the risk of developing anti-citrullinated peptide antibody (ACPA)⁺ RA, particularly in individuals with high-risk RA-susceptibility alleles. Other contributory environmental risks including particulate exposure, periodontal disease, bronchiectasis, diet, obesity and the oral contraceptive impact respiratory, oral, intestinal and genital tract mucosal sites. Furthermore, the first signs of autoimmunity may appear at mucosal sites e.g. sputum ACPA-IgA and IgG. While oral and faecal dysbiosis are well described, there is no consistent single bacterial species that appears to drive RA. Animal and human data suggest a model in which multiple environmental influences impact mucosal immune function through the host genetics through enhanced mucosal permeability and the traffic of pro-inflammatory PAMPs and the amplification of autoimmune responses. In some cases, autoimmunity may be driven by cross-reactivity, or mimicry, to pathogen-specific antigens, particularly where the host immune system fails to support their rapid control and elimination.

A review of the influence of periodontal treatment in systemic diseases

The effects and consequences of periodontal diseases might not be confined to the oral cavity. A great body of evidence has arisen supporting the claim demonstrating an association with several systemic conditions and diseases. With different levels of evidence, an association between periodontal disease and cardiovascular disease, diabetes, psoriasis, rheumatoid arthritis, pregnancy outcomes and respiratory diseases has been established. However, the true nature of this association, if it is causal, still remains elusive. For a better understanding of the complex relationships linking different conditions, interventional studies now begin to focus on the possible outcomes of periodontal treatment in relation to the events, symptoms and biomarkers of several systemic disorders, assessing if periodontal treatment has any impact on them, hopefully reducing their severity or prevalence. Therefore, we proceeded to review the recent literature on the subject, attempting to present a brief explanation of the systemic condition or disease, what proposed mechanisms might give biological plausibility to its association with periodontal disease, and finally and more importantly, what data are currently available pertaining to the effects periodontal treatment may have. Raising awareness and discussing the possible benefits of periodontal treatment on overall systemic health is important, in order to change the perception that periodontal diseases are only limited to the oral cavity, and ultimately providing better and comprehensive care to patients.

Rheumatoid arthritis is associated with early tooth loss: results from Korea National Health and Nutrition Examination Survey V to VI

BACKGROUND/AIMS

To examine the association between rheumatoid arthritis (RA) and periodontitis or tooth loss.

METHODS

The study used data from the fifth and sixth Korea National Health and Nutrition Examination Surveys conducted from 2010 to 2015. RA was defined as participant-reported physician-diagnosed RA that was being treated. Periodontitis and the number of natural teeth were determined by dental examination. Periodontitis was defined according to the community periodontal index (periodontal probing depth ≥ 4 mm). The association between RA and periodontitis or tooth loss was examined after controlling for confounding variables (e.g., age, smoking status, socioeconomic status, dental caries, frequency of toothbrushing, body mass index, alcohol consumption, and diabetes) in men and women. Subgroup analyses stratified by age were also performed.

RESULTS

The study enrolled 20,297 participants aged ≥ 19 years (157 RA patients and 20,140 non-RA controls). There was no association between RA and periodontitis or tooth loss in men and women. Subgroup analyses in those aged < 60 years revealed a non-significant association between RA and periodontitis (adjusted odds ratio, 1.53; p = 0.162), but they revealed a significant association between RA and tooth loss (adjusted β, 0.20; p = 0.042).

CONCLUSION

RA was not associated with periodontitis, but was associated with tooth loss in younger adults. Younger RA patients are more likely to suffer tooth loss than general younger population; thus dental management is required.

The microbiome in autoimmune diseases

The microbiome is represented by microorganisms which live in a symbiotic way with the mammalian. Microorganisms have the ability to influence different physiological aspects such as the immune system, metabolism and behaviour. In recent years, several studies have highlighted the role of the microbiome in the pathogenesis of autoimmune diseases. Notably, in systemic lupus erythematosus an alteration of the intestinal flora (lower Firmicutes/Bacteroidetes ratio) has been described. Conversely, changes to the gut commensal and periodontal disease have been proposed as important factors in the pathogenesis of rheumatoid arthritis. At the same time, other autoimmune diseases (i.e. systemic sclerosis, Sjögren's syndrome and anti-phospholipid syndrome) also share modifications of the microbiome in the intestinal tract and oral flora. Herein, we describe the role of the microbiome in the maintenance homeostasis of the immune system and then the alterations of the microorganisms that occur in systemic autoimmune diseases. Finally, we will consider the use of probiotics and faecal transplantation as novel therapeutic targets.

Gums and joints: is there a connection? Part one: epidemiological and clinical links

Rheumatoid arthritis (RA) and chronic periodontitis are common chronic inflammatory diseases that share numerous clinical and pathobiological characteristics. Due to their similarities, despite manifesting at anatomically distinct sites, the relationship between these two diseases has been investigated for many years. This review attempts to summarise the state of the field based on evidence published in the last ten years.

The association between gravidity, parity and the risk of developing rheumatoid arthritis: A systematic review and meta-analysis

OBJECTIVE

To establish if gravidity and parity associate with the development of rheumatoid arthritis (RA), and to establish if this effect is influenced by the time elapsed since pregnancy/childbirth, the number of pregnancies/childbirths, and serological status, through systematically reviewing the literature and undertaking a meta-analysis.

METHODS

We searched Medline/EMBASE (from 1946 to 2018) using the terms "rheumatoid arthritis.mp" or "arthritis, rheumatoid/" and "pregnancy.mp" or "pregnancy/" or "parity.mp" or "parity/" or "gravidity.mp" or "gravidity/" (observational study filter applied). Case-control/cohort studies that examined the relationship between parity/gravidity and the risk of RA in women were included. Studies reporting effect size data for RA in ever vs. never parous/gravid women as ORs/RRs with 95% confidence intervals were included in a meta-analysis. Other relationships (i.e. risk by pregnancy/childbirth numbers) were analysed descriptively.

RESULTS

Twenty studies (from 626 articles) met our inclusion criteria, comprising 14 case-control (4799 cases; 11,941 controls) and 6 cohort studies (8575 cases; 2,368,439 individuals). No significant association was observed in the meta-analysis of studies reporting the risk of RA in ever vs. never parous women (OR 0.91; 95% CI 0.80-1.04) and ever vs. never gravid women (OR 0.86; 95% CI 0.46-1.62). No consistent evidence of a relationship between the number of pregnancies/childbirths and RA risk was seen. No significant association was observed between being pregnant, or in the immediate post-partum period, and the risk of developing RA.

CONCLUSION

Our systematic review does not support the concept that gravidity and parity are associated with the risk of RA development.

Does periodontitis represent a risk factor for rheumatoid arthritis? A systematic review and meta-analysis

Periodontitis is an inflammatory disease of dental supporting tissues (gingiva, periodontal ligament, and bone) and it has been suggested as a possible etiology for rheumatoid arthritis (RA). In this systematic review, we aim to verify if periodontitis represents a risk factor for RA. Electronic databases were consulted until March 2018 considering eligibility criteria focusing on: (P, participants) adults; (E, exposure) with periodontitis; (C, comparison) without periodontitis; and (O, outcome) development of RA. Quality assessment of studies and risk-of-bias evaluation were also performed. To undertake a quantitative analysis, the number of persons with RA and a total number of participants for the case group (with periodontitis) and control group (without periodontitis) were used to calculate the odds ratio (OR) with a 95% confidence interval (CI). A total of 3888 articles were identified, and nine studies were considered eligible. Seven of 9 articles suggested an association among diseases by the common pro-inflammatory profiles. The pooled analysis of 3 articles showed a higher RA prevalence for persons with periodontitis (n = 1177) than controls (n = 254) (OR 1.97; CI 1.68–2.31; p < 0.00001). However, considerable heterogeneity among studies was verified (I² = 96%, p < 0.00001). Periodontitis may represent a risk factor for RA by heredity, bacterial infection, and the pro-inflammatory profile shared between both diseases. Although most of the elective studies report an association between periodontitis and RA, the quantitative analysis showed a high heterogeneity, leading to the need for further studies.

Potential of Lifestyle Changes for Reducing the Risk of Developing Rheumatoid Arthritis: Is an Ounce of Prevention Worth a Pound of Cure?

PURPOSE

Lifestyle may be important in the development of rheumatoid arthritis (RA). Therefore, changing behaviors may delay or even prevent RA onset. This article reviews the evidence basis for the associations of lifestyle factors with RA risk and considers future directions for possible interventions to reduce RA risk.

METHODS

The literature was reviewed for cross-sectional studies, case-control studies, cohort studies, and clinical trials investigating potentially modifiable lifestyle factors and RA risk or surrogate outcomes on the path toward development such as RA-related autoimmunity or inflammatory arthritis. The evidence related to cigarette smoking, excess weight, dietary intake, physical activity, and dental health for RA risk were summarized.

FINDINGS

Cigarette smoking has the strongest evidence base as a modifiable lifestyle behavior for increased seropositive RA risk. Smoking may increase seropositive RA risk through gene-environment interactions, increasing inflammation and citrullination locally in pulmonary/oral mucosa or systemically, thereby inducing RA-related autoimmunity. Prolonged smoking cessation may reduce seropositive RA risk. Evidence suggests that excess weight can increase RA risk, although this effect may differ according to sex, serologic status, and age at RA onset. TDietary intake may also affect RA risk: overall healthier patterns, high fish/omega-3 polyunsaturated fatty acid consumption, and moderate alcohol intake may reduce RA risk, whereas caffeine and sugar-sweetened soda consumption might increase RA risk. The impact of physical activity is less clear, but high levels may reduce RA risk. Periodontal disease might induce citrullination and RA-related autoimmunity, but the effect of dental hygiene behaviors on RA risk is unclear. Although the effect size estimates for these lifestyle factors on RA risk are generally modest, there may be relatively large public health benefits for targeted interventions given the high prevalence of these unhealthy behaviors. With the exception of smoking cessation, the impact of behavior change of these lifestyle factors on subsequent RA risk has not been established. Nearly all of the evidence for lifestyle factors and RA risk were derived from observational studies.

IMPLICATIONS

There are many potentially modifiable lifestyle factors that may affect RA risk. Improving health behaviors could have large public health benefits for RA risk given the high prevalence of many of the RA risk-related lifestyle factors. However, future research is needed to establish the effects of lifestyle changes on RA risk or surrogate outcomes such as RA-related autoimmunity or inflammatory arthritis.

Periodontal status correlates with anti-citrullinated protein antibodies in first-degree relatives of individuals with rheumatoid arthritis

AIM

To evaluate periodontal status in first-degree relatives of patients with rheumatoid arthritis (FDR-RA) and detect correlation with the presence of anti-citrullinated protein antibodies (ACPAs).

MATERIALS AND METHODS

Rheumatologic status and periodontal status were evaluated in a nested case-control study of FDR-RA with no diagnosis of RA at enrolment. The following parameters were assessed in 34 ACPA-positive (ACPA+) and 65 ACPA-negative (ACPA-) subjects: gingival index (GI), plaque index (PI), probing depth (PD), bleeding on probing (BOP) and clinical attachment level (CAL). We compared the two groups using conditional logistic regression.

RESULTS

In ACPA+ individuals, the mean, PD, BOP, CAL and number of sites per person with PD > 4 mm and BOP were significantly higher compared to the ACPA- group. All ACPA+ subjects had periodontitis: 44.1% presenting moderate and 47.1% severe periodontitis. ACPA- subjects had mainly mild (30.8%) and moderate (27%) periodontitis, differences being significantly different for both moderate periodontitis (p = 0.001) and severe periodontitis (p < 0.001). In multivariable analyses, ACPA status (p = 0.04) and age (p = 0.002) were significantly and independently associated with periodontal conditions.

CONCLUSION

High prevalence and severity of periodontitis in FDR-RA was associated with seropositivity to ACPAs. This further strengthens the hypothesis that periodontitis may be a risk factor in the development of RA.

Periodontal Health and Oral Microbiota in Patients with Rheumatoid Arthritis

This study aimed to investigate the periodontal health of patients with established rheumatoid arthritis (RA) in relation to oral microbiota, systemic and oral inflammatory mediators, and RA disease activity. Forty patients underwent full-mouth dental/periodontal and rheumatological examination, including collection of blood, saliva, gingival crevicular fluid (GCF) and subgingival plaque. Composition of plaque and saliva microbiota were analysed using 16S rRNA sequencing and levels of inflammatory mediators by multiplex-immunoassay. The majority of the patients (75%) had moderate or severe periodontitis and the rest had no/mild periodontitis. Anti-citrullinated protein antibody (ACPA) positivity was significantly more frequent in the moderate/severe periodontitis (86%) compared to the no/mild group (50%). No significance between groups was observed for RA disease duration or activity, or type of medication. Levels of sCD30/TNFRSF8, IFN-α2, IL-19, IL-26, MMP-1, gp130/sIL-6Rß, and sTNF-R1 were significantly higher in serum or GCF, and April/TNFSF13 was significantly higher in serum and saliva samples in moderate/severe periodontitis. The microbial composition in plaque also differed significantly between the two groups. In conclusion, the majority of RA patients had moderate/severe periodontitis and that this severe form of the disease was significantly associated with ACPA positivity, an altered subgingival microbial profile, and increased levels of systemic and oral inflammatory mediators.

Personalization of biologic therapy in patients with rheumatoid arthritis: less frequently accounted choice-driving variables

Objective

To propose appropriate statements that drive the choice of biologic therapies in patients with rheumatoid arthritis (RA), factoring in their impact on the following issues: anti-drug antibody (ADAb) formation, suspicion and management of infections, lupus-like syndrome (LLS), effects on bone mass and sexual sphere, and relationship between RA and periodontal disease (PD).

Methods

An overview of existing evidence was undertaken by an expert panel on behalf of the Italian board for the TAilored BIOlogic therapy (ITABIO). Data were extracted from controlled trials, national registries, national health care databases, post-marketing surveys, and, when required by the paucity of controlled studies, from open-label clinical series. Anti-tumor necrosis factor (anti-TNF) and non-anti-TNF-targeted biologics approved for RA were investigated.

Results

ADAb formation is chiefly associated with anti-TNFs, and it is reduced by combination therapy with methotrexate. To date, ADAb titration is not advisable for clinical practice, and, in case of anti-TNF secondary failure, a non-anti-TNF biologic is indicated. LLS is observed in anti-TNF receivers and, in most cases, resolves without anti-TNF withdrawal. A non-anti-TNF biologic is advisable in patients experiencing LLS. Non-anti-TNFs demonstrated a low or absent infection risk and are preferable in patients with comorbidities. Due to their positive effects on bone mass, anti-TNFs are indicated in women at osteoporosis risk, whereas non-anti-TNF have been poorly investigated. The emerging evidence of the relationship between RA and PD and the effects on anti-TNF efficacy should lead clinicians to consider the periodontal status in RA patients. Anti-TNFs may exert a positive effect on fertility and sexuality, and clinicians should explore these aspects in RA patients.

Conclusion

The optimization of biologic therapies by taking into proper account the above issues would improve patient outcomes.

Association of Periodontitis with Rheumatoid Arthritis and the Effect of Non-Surgical Periodontal Treatment on Disease Activity in Patients with Rheumatoid Arthritis

BACKGROUND The association of periodontitis (PD) with the prevalence of rheumatoid arthritis (RA) remains controversial. Therefore, the aim of this study was to evaluate their correlation and investigate the effects of non-surgical periodontal treatment on RA. MATERIAL AND METHODS A total of 64 patients were enrolled in this study and divided into 4 groups: 18 PD patients (PD+RA-), 18 RA patients (PD-RA+), 18 RA with PD patients (PD+RA+), and 10 healthy controls (PD-RA-). Periodontal and rheumatologic parameters were examined at baseline and 1 month following non-surgical periodontal treatment. RESULTS Our results showed that RA patients had similar periodontal status. However, patients in the PD+RA+ group had significantly higher levels of rheumatologic parameters such as C-reactive protein (CRP), anti-cyclic citrulline peptide antibody (ACPA), erythrocyte sedimentation rate (ESR), and Disease Activity Score 28 (DAS28) than those in the PD-RA+ group. In addition, non-surgical periodontal treatment was efficacious in improving rheumatologic parameters of patients in the PD+RA+ group. CONCLUSIONS The presence of PD might contribute to the progression of RA, while RA might have little effect on accelerating the development of PD. In addition, RA patients with PD receiving non-surgical periodontal treatment resulted in noteworthy improvement in the clinical outcome for RA.

Hypoxia induces production of citrullinated proteins in human fibroblast-like synoviocytes through regulating HIF1α

Hypoxia is a prominent microenvironment feature in a range of disorders including cancer, rheumatoid arthritis (RA), atherosclerosis, inflammatory bowel disease (IBD), infection and obesity. Hypoxia promotes biological functions of fibroblast-like synoviocytes via regulating hypoxia-inducible factor 1α (HIF1α). Dysregulated protein citrullination in RA drives the production of antibodies to citrullinated proteins, a highly specific biomarker of RA. However, the mechanisms promoting citrullination in RA are not yet fully elucidated. In this study, we investigated whether pathophysiological hypoxia as found in the rheumatoid synovium modulates the citrullination in human fibroblast-like synoviocytes (HFLS). Here, we found that peptidylarginine deiminase 2 (PAD2) and citrullinated proteins were increased in HFLS after exposure to hypoxia. Moreover, knocking down HIF1α by HIF1α siRNA ameliorated the expression of PAD2 and citrullinated proteins. Collectively, this study provides a new mechanism involved in generating citrullinated proteins: hypoxia promotes citrullination and PAD production in HFLS. Concurrently, we also proposed a novel hypoxia involved mechanism in RA pathogenesis. This study deepens our understanding of the role of hypoxia in the pathogenesis of RA and provides a potential therapeutic strategy for RA.

Association Between Marginal Jawbone Loss and Onset of Rheumatoid Arthritis and Relationship to Plasma Levels of RANKL

OBJECTIVE

To investigate whether periodontitis, characterized by marginal jawbone loss, precedes the onset of symptoms of rheumatoid arthritis (RA), and to analyze plasma levels of RANKL (a cytokine that is crucial for bone resorption) and anti-citrullinated peptide antibodies (ACPAs) in presymptomatic individuals compared with matched referent controls.

METHODS

Marginal jawbone loss was measured on dental radiographs of the premolar/molar regions in the jaws in 176 subjects, 93 of whom subsequently developed RA. Among these participating subjects, 46 had documented radiographs predating symptom onset, and 45 cases could be matched to controls, according to sex, age, and smoking status. Plasma RANKL concentrations were analyzed using enzyme-linked immunosorbent assay. A receiver operating characteristic curve was used to define the cutoff value for RANKL positivity.

RESULTS

Bone loss was significantly greater in presymptomatic subjects classified as never smokers compared with that in controls, and increasing levels of bone loss were associated with a higher risk of the subsequent development of RA (hazard ratio 1.03, 95% confidence interval 1.01-1.05). No association between jawbone loss and RA was observed in smokers. A significantly greater extent of marginal jawbone loss was detected in RANKL-positive presymptomatic subjects, and even more pronounced jawbone loss was observed in those who were positive for both RANKL and ACPA.

CONCLUSION

Marginal jawbone loss preceded the clinical onset of RA symptoms, but this was observed only in nonsmokers. Moreover, marginal jawbone loss was significantly greater in RANKL-positive presymptomatic subjects compared with RANKL-negative presymptomatic subjects and was highest in presymptomatic subjects positive for both ACPA and RANKL.

Effects of lentivirus-mediated ornithine decarboxylase gene on the proliferation and apoptosis of fibroblast-like synoviocytes in rats with arthritis

OBJECTIVE

This study aimed to explore the effects of lentivirus-mediated ornithine decarboxylase (ODC) gene on the proliferation and apoptosis of fibroblast-like synoviocytes (FLSs) in rats with rheumatoid arthritis (RA).

METHODS

Twenty Lewis rats were randomized into control group (ten rats without processing) and RA group (ten rats of adjuvant-induced arthritis). The third-generation FLSs were randomized into test, control and blank groups. MTT assay and flow cytometry were employed to detect cell proliferation and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of tumor necrosis factor α (TNF-α), interferon-γ (IFN-γ), and interleukin-2 (IL-2).

RESULTS

Lewis rats in the RA group became ill from 11days on and got seriously ill 18days after modeling. However, rats in the control group had no obvious change. MTT assay showed that the test group had higher cell proliferation than the blank and control groups (P₁<0.001; P₂<0.001). Flow cytometry revealed that the apoptosis of FLSs in the test group was significantly lower than that in the blank and control groups (P₁<0.001; P₂<0.001). ELISA showed that the test group had higher TNF-α, IFN-γ and IL-2 level than the control and blank groups (all P<0.001), but no significant difference was found between the control and blank groups (all P>0.05).

CONCLUSION

The results indicated that overexpression of ODC gene promotes the proliferation while suppressing apoptosis of FLSs in rats with RA.

Role of human microbiome and selected bacterial infections in the pathogenesis of rheumatoid arthritis

Microorganisms inhabiting human body form a complex ecosystem. The mutual influence of the microbiome and the immune system of the host constitute the basis for numerous diseases, e.g. pseudomembranous colitis, inflammatory bowel disease, type 1 diabetes, atopic diseases, obesity, reactive arthritis. New molecular diagnostic methods and multi-center studies may help in understanding of the role of microbiota in health and disease. Rheumatoid arthritis has a multi-faceted etiology, and its causes are not entirely understood. There are indications for the influence of microbiomes of oral cavity, intestines, lungs and urinary tract on the development of rheumatoid arthritis. Interactions between microorganisms and human immune system play role in the pathogenesis of the disease.

Factors associated with the risk of gingival disease in patients with rheumatoid arthritis

Gingival disase and rheumatoid arthritis (RA) are linked at both the epidemiologic and pathogenesis levels. In this study, we aimed to identify environmental factors associated with RA and gingival disease and to investigate factors that protect the gingival tissue in RA patients. This retrospective study analyzed 754 RA patients with gingival disease selected from the NHANES database who completed the mobile examination center interview/examination between 1999 and 2004. Data collected included demographics, lifestyle, dietary intake, and biomarkers. The study included 173 RA patients with gingival disease. Multivariate logistic regression analysis showed that the odds of gingival disease were significantly increased with male gender. However, the odds of gingival disease was significantly decreased with increased vitamin C intake (OR = 0.996, p = 0.041), and higher serum vitamin D levels (OR = 0.979, p = 0.011). Given the significant association between the prevalence of gingival disease and RA, identification of risk factors of gingival disease will be useful as a screening tool in national health surveys to improve the management of periodontal disease in patients with RA.

The Infectious Basis of ACPA-Positive Rheumatoid Arthritis

Rheumatoid arthritis (RA) is associated with HLA-DRB1 shared epitope (HLA-DRB1SE) and anti-citrullinated protein autoantibodies (ACPAs). ACPAs precedes the onset of clinical and subclinical RA. There are strong data for three infectious agents as autoimmunity triggers in RA, namely Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans causes of periodontal disease (PD), and Epstein-Barr virus (EBV). P. gingivalis expresses arginine gingipains, that cleave proteins at the arginine residues, and peptidyl arginine deiminase (PPAD), which citrullinates arginine residues of proteins, thus forming neoantigens that lead to ACPA production. Peripheral blood plasmablasts from ACPA+RA patients produce ACPAs the majority of which react against P. gingivalis. A. actinocycetemcomitans produces leukotoxin A, a toxin that forms pores in the neutrophil membranes and leads to citrullination and release of citrullinated autoantigens in the gums. EBV can infect B cells and epithelial cells and resides as latent infection in resting B cells. Abs against citrullinated peptides derived from EBV nuclear antigen appear years before RA and cross-react with human citrullinated fibrin. Citrullinated proteins are potential arthritogenic autoantigens in RA. The conversion of arginine to citrulline increases the peptide binding affinity to HLA-DRB1SE. Also, citrullinated fibrinogen induces arthritis in HLA-DRB1^*0401 transgenic mice, and transfer of their splenic T cells causes arthritis to recipient mice.

Genetic and environmental risk factors for rheumatoid arthritis

Multiple genetic and environmental factors have been associated with an increased risk for rheumatoid arthritis (RA). Of these, the strongest associations have been seen with female sex, a family history of RA, the genetic factor the "shared epitope," and exposure to tobacco smoke. There is also renewed interest in mucosal inflammation and microbial factors as contributors to the development of RA. However, the identification of a "preclinical" period of RA that can be defined as local or systemic autoimmunity as measured by autoantibodies and other biomarkers prior to the development of clinically apparent synovitis suggests that the risk factors for RA are acting long prior to first clinical evidence of IA. As such, a major challenge to the field will be to investigate the full spectrum of the development of RA, from initiation and propagation of autoimmunity during preclinical RA and transition to clinically apparent synovitis and classifiable RA, to determine which genetic and environmental factors are important at each stage of disease development. Understanding the exact role and timing of action of risk factors for RA is especially important given the advent of prevention trials in RA, and the hope that a full understanding of genetic and environmental factors in RA could lead to effective preventive interventions.

Orofacial manifestations in patients with inflammatory rheumatic diseases

The main orofacial manifestation of the inflammatory rheumatic diseases is that of Sjögren's syndrome. In addition, there is a constellation of orofacial manifestations of the inflammatory rheumatic diseases, many of which are extra-articular with some constituting presenting signs of the underlying rheumatic disease. This review will discuss the orofacial manifestations in a variety of connective tissue diseases and will also allude to the oral adverse drug reactions that may occur as a consequence of therapy.

Infections as a cause of autoimmune rheumatic diseases

Exogenous and endogenous environmental exposures and particularly infections may participate in the breakage of tolerance and the induction of autoimmunity in rheumatic diseases. Response to infections apparently occurs years before clinical manifestations and features of autoimmunity, such as autoantibodies, are detected years before clinical manifestations in autoimmune rheumatic diseases. In this review, we summarize the current evidence for a potential causal link between infectious agents and rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, Sjogren’s syndrome and ANCA-associated vasculitis.

Immune recognition of citrullinated epitopes

Conversion of arginine into citrulline is a post-translational modification that is observed in normal physiological processes. However, abnormal citrullination can provoke autoimmunity by generating altered self-epitopes that are specifically targeted by autoantibodies and T cells. In this review we discuss the recognition of citrullinated antigens in human autoimmune diseases and the role that this modification plays in increasing antigenic diversity and circumventing tolerance mechanisms. Early published work demonstrated that citrullinated proteins are specifically targeted by autoantibodies in rheumatoid arthritis and that citrullinated peptides are more readily presented to T cells by arthritis-susceptible HLA class II 'shared epitope' proteins. Emerging data support the relevance of citrullinated epitopes in other autoimmune diseases, including type 1 diabetes and multiple sclerosis, whose susceptible HLA haplotypes also preferentially present citrullinated peptides. In these settings, autoimmune patients have been shown to have elevated responses to citrullinated epitopes derived from tissue-specific antigens. Contrasting evidence implicates autophagy or perforin and complement-mediated membrane attack as inducers of ectopic citrullination. In either case, the peptidyl deiminases responsible for citrullination are activated in response to inflammation or insult, providing a mechanistic link between this post-translational modification and interactions with the environment and infection. As such, it is likely that immune recognition of citrullinated epitopes also plays a role in pathogen clearance. Indeed, our recent data suggest that responses to citrullinated peptides facilitate recognition of novel influenza strains. Therefore, increased understanding of responses to citrullinated epitopes may provide important insights about the initiation of autoimmunity and recognition of heterologous viruses.

Impaired Porphyromonas gingivalis-Induced Tumor Necrosis Factor Production by Dendritic Cells Typifies Patients With Rheumatoid Arthritis

OBJECTIVE

The prevalence of periodontitis is increased in patients with rheumatoid arthritis (RA), and the severity of periodontitis can affect the level of arthritis. Porphyromonas gingivalis is one of the main bacteria involved in periodontitis. Our aim was to determine if there are differences in the innate immune response against P gingivalis between healthy controls and RA patients.

METHODS

Monocyte-derived dendritic cells (DCs) from healthy controls, RA patients, and patients with psoriatic arthritis (PsA) were stimulated with P gingivalis, a range of other bacteria, and Toll-like receptor agonists. Cytokine production was determined, and blocking studies were performed to determine which receptors were involved in differential recognition of P gingivalis. Effects on T cell cytokines were also determined in cultures of peripheral blood mononuclear cells (PBMCs).

RESULTS

Upon stimulation with P gingivalis, RA patient DCs produced less tumor necrosis factor as compared to healthy control DCs, which was not observed in PsA patients or upon stimulation with other bacteria. In addition, P gingivalis-mediated activation of RA patient PBMCs showed a clear reduction of interferon-γ production. Among the various possible underlying mechanisms investigated, only blockade of CR3 abolished the difference between RA patients and healthy controls, suggesting the involvement of CR3 in this process.

CONCLUSION

Immune cells from RA patients display a reduced response to P gingivalis, which has functional consequences for the immune response. This may result in prolonged survival of P gingivalis, possibly driving autoantibody formation and a self-perpetuating loop of chronic inflammation. The possible role of CR3 in this process warrants further investigation.

Periodontal bacterial colonization in synovial tissues exacerbates collagen-induced arthritis in B10.RIII mice

Background

It has been previously hypothesized that oral microbes may be an etiological link between rheumatoid arthritis (RA) and periodontal disease. However, the mechanistic basis of this association is incompletely understood. Here, we investigated the role of periodontal bacteria in induction of joint inflammation in collagen-induced arthritis (CIA) in B10.RIII mice.

Methods

CIA-prone B10.RIII mice were infected orally with a polybacterial mixture of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 24 weeks before induction of CIA. The ability of polybacterial mixture to colonize the periodontium and induce systemic response, horizontal alveolar bone resorption in infected B10.RIII mice was investigated. Arthritis incidence, severity of joint inflammation, pannus formation, skeletal damage, hematogenous dissemination of the infection, matrix metalloproteinase 3 (MMP3) levels, and interleukin-17 expression levels were evaluated.

Results

B10.RIII mice had gingival colonization with all three bacteria, higher levels of anti-bacterial immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies, significant alveolar bone resorption, and hematogenous dissemination of P. gingivalis to synovial joints. Infected B10.RIII mice had more severe arthritis, and higher serum matrix metalloproteinase 3 levels and activity. Histopathological analysis showed increased inflammatory cell infiltration, destruction of articular cartilage, erosions, and pannus formation. Additionally, involved joints showed had expression levels of interleukin-17.

Conclusion

These findings demonstrate that physical presence of periodontal bacteria in synovial joints of B10.RIII mice with collagen-induced arthritis is associated with arthritis exacerbation, and support the hypothesis that oral bacteria, specifically P. gingivalis, play a significant role in augmenting autoimmune arthritis due to their intravascular dissemination to the joints.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1056-4) contains supplementary material, which is available to authorized users.

Prevalence of Periodontitis in Patients with Established Rheumatoid Arthritis: A Swedish Population Based Case-Control Study

INTRODUCTION

The possible hypothesis of a link between periodontitis and rheumatoid arthritis (RA), specifically anti-citrullinated protein antibody (ACPA) positive RA, prompted us to investigate the prevalence of periodontitis in the Swedish Epidemiological Investigation of RA (EIRA), a well-characterised population-based RA case-control cohort.

METHODS

Periodontal status of 2,740 RA cases and 3,942 matched controls was retrieved through linking EIRA with the National Dental Health Registry (DHR), where dental diagnostic- and treatment codes on the adult Swedish population have been registered. Dental records from 100 cases and controls were reviewed to validate the periodontal diagnostic codes in DHR.

RESULTS

The reviewed dental records confirmed 90% of the periodontitis diagnoses in DHR among RA cases, and 88% among controls. We found the positive predictive value of periodontitis diagnoses in the DHR to be 89% (95% CI 78 to 95%) with a sensitivity of 77% (95% CI: 65 to 86%). In total, 86% of EIRA participants were identified in DHR. The risk for periodontitis increased by age and current smoking status in both cases as well as controls. No significant differences in prevalence of periodontal disease in terms of gingivitis, periodontitis, peri-implantitis or increased risk for periodontitis or peri-implantitis were observed between RA cases and controls. In addition, there was no difference on the basis of seropositivity, ACPA or rheumatoid factor (RF), among patients with RA.

CONCLUSIONS

Our data verify that smoking and ageing are risk factors for periodontitis, both in RA and controls. We found no evidence of an increased prevalence of periodontitis in patients with established RA compared to healthy controls, and no differences based on ACPA or RF status among RA subjects.

Periodontal systemic associations: review of the evidence

AIM

To critically appraise recent research into associations between periodontal disease and systemic diseases and conditions specifically respiratory disease, chronic kidney disease, rheumatoid arthritis, cognitive impairment, obesity, metabolic syndrome and cancer.

METHODS

A MEDLINE literature search of papers published between 2002 and April 2012 was conducted. Studies that included periodontitis as an exposure were identified. Cross-sectional epidemiological investigations on large samples, prospective studies and systematic reviews formed the basis of the narrative review. A threshold set for the identification of periodontitis was used to identify those studies that contributed to the conclusions of the review.

RESULTS

Many of the investigations were cross-sectional secondary analyses of existing data sets in particular the NHANES studies. There were a small number of systematic reviews and prospective studies. There was substantial variability in the definitions of exposure to periodontitis. A small number of studies met the threshold set for periodontitis and supported associations; however, in some of the chronic diseases there were no such studies. There was strong evidence from randomized controlled trials that interventions, which improve oral hygiene have positive effects on the prevention of nosocomial pneumonias.

CONCLUSIONS

There was substantial heterogeneity in the definitions used to identify periodontitis and very few studies met a stringent threshold for periodontitis. Published evidence supports modest associations between periodontitis and some, although not all, of the diseases and conditions reviewed. There is a need to reach a consensus on what constitutes periodontitis for future studies of putative associations with systemic diseases.