Preclinical Rheumatoid Arthritis Research Articles

Evaluation of the clinical performance of anti-mutated citrullinated vimentin antibody and 14-3-3 eta testing in rheumatoid arthritis.

Early rheumatoid arthritis (RA) detection is crucial for improving patient prognosis. Anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factors (RF) support RA diagnosis but are undetectable in ∼20 % of cases. Recently, antibodies against mutated citrullinated vimentin (anti-MCV) and detection of 14-3-3 eta have emerged with implications for preclinical RA diagnosis and monitoring treatment. The objective of this study was to assess the clinical performance of anti-MCV antibodies and 14-3-3 eta in RA and to compare it to current RA criteria anti-CCP and RF markers, individually and in combination. A retrospective chart review of 326 subjects submitted for RA serology testing identified 134 RA positive and 192 RA negative disease control individuals. Fifty healthy controls specimens were also included. Performance of anti-MCV and 14-3-3 eta, alone and combined with CCP3.1 and RF, was assessed. Anti-MCV had a sensitivity of 71 % and a specificity of 92 %. 14-3-3 eta had a sensitivity of 43 % and a specificity of 90 %. In comparison, CCP3.1 and RF displayed a sensitivity of 79 % and 84 % and a specificity of 92 % and 61 %, respectively. ROC curve analysis demonstrated CCP3.1 and anti-MCV had superior diagnostic performance compared to RF and 14-3-3 eta. In our cohort, anti-MCV and 14-3-3 eta failed to identify seronegative RA patients. Different combinations of double antibody positivity increased specificity at the cost of lost sensitivity. Individually, 14-3-3 eta, anti-MCV and CCP3.1 assays had≥90 % specificity in diagnosed RA patients, with better sensitivities for anti-MCV and CCP3.1 than 14-3-3 eta. Overall diagnostic performance of anti-MCV was similar to CCP3.1 and RF, all of which outperformed 14-3-3 eta in our cohort.

Biomarkers in the diagnosis, prognosis and management of rheumatoid arthritis: A comprehensive review.

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune condition that primarily affects the joints and periarticular soft tissues. In the past two decades, the discovery of new biomarkers has contributed to advances in the understanding of the pathogenesis and natural history of RA. These biomarkers, including genetic, clinical, serological and imaging biomarkers, play a key role in the different stages and aspects of RA, from the so called 'pre-clinical RA', which is characterized by subclinical pathological events, such as autoimmunity and inflammation, to diagnosis (including differential diagnosis), treatment decision making and disease monitoring.This review will provide an overview on the current role of traditional and newer biomarkers in the main aspects of RA management, from the identification of individuals 'at-risk' of RA who are likely to progress to clinically evident disease, to 'early' diagnosis of RA, prognosis, precision medicine, and prediction of response to treatment.

Calcitonin treatment for osteoarthritis and rheumatoid arthritis - a systematic review and meta-analysis of preclinical data.

The aim of this study was to investigate the efficacy of calcitonin (CT) in animal models of experimental osteoarthritis (OA) and rheumatoid arthritis (RA), as new stabilized CT formulations are currently being introduced. A comprehensive and systemic literature search was conducted in PubMed/MEDLINE and Embase databases to identify articles with original data on CT treatment of preclinical OA and RA. Methodological quality was assessed using the Systematic Review Centre for Laboratory Animal Experimentation's risk of bias tool for animal intervention studies. To provide summary estimates of efficacy, a meta-analysis was conducted for outcomes reported in four or more studies, using a random-effects model. Subgroup analyses were employed to correct for study specifics. Twenty-six studies were ultimately evaluated and data from 16 studies could be analyzed in the meta-analysis, which included the following outcomes: bone mineral density, bone volume, levels of cross-linked C-telopeptide of type I collagen, histopathological arthritis score, and mechanical allodynia. For all considered outcome parameters, CT-treated groups were significantly superior to control groups (P = 0.002; P = 0.01; P < 0.00001; P < 0.00001; P = 0.04). For most outcomes, effect sizes were significantly greater in OA than in RA (P ≤ 0.025). High in-between study heterogeneity was detected. There is preclinical evidence for an antioxidant, anti-inflammatory, antinociceptive, cartilage- and bone-protective effect of CT in RA and OA. Given these effects, CT presents a promising agent for the treatment of both diseases, although the potential seems to be greater in OA.

Cachexia in preclinical rheumatoid arthritis: Longitudinal observational study of thigh magnetic resonance imaging from osteoarthritis initiative cohort.

Preclinical rheumatoid arthritis (Pre-RA) is defined as the early stage before the development of clinical RA. While cachexia is a well-known and potentially modifiable complication of RA, it is not known if such an association exists also in the Pre-RA stage. To investigate such issue, we aimed to compare the longitudinal alterations in the muscle composition and adiposity of participants with Pre-RA with the matched controls. In this observational cohort study, the Osteoarthritis Initiative (OAI) participants were categorized into Pre-RA and propensity score (PS)-matched control groups. Pre-RA was retrospectively defined as the absence of RA from baseline to year-2, with progression to physician-diagnosed clinical RA between years 3-8 of the follow-up period. Using a validated deep learning algorithm, we measured MRI biomarkers of thigh muscles and adiposity at baseline and year-2 follow-ups of the cohort. The outcomes were the differences between Pre-RA and control groups in the 2-year rate of change for thigh muscle composition [cross-sectional area (CSA) and intramuscular adipose tissue (Intra-MAT)] and adiposity [intermuscular adipose tissue (Inter-MAT) and subcutaneous adipose tissue (SAT)]. Linear mixed-effect regression models were used for comparison. After 1:3 PS-matching of the groups for confounding variables (demographics, risk factors, co-morbidities, and knee osteoarthritis status), 408 thighs (102 Pre-RA and 306 control) of 322 participants were included (age mean±SD: 61.7±8.9years; female/male: 1.8). Over a 2-year period, Pre-RA was associated with a larger decrease in total thigh muscle CSA [estimate, 95% confidence interval (CI): -180.13mm2/2-year, -252.80 to -107.47, P-value<0.001]. Further examination of thigh muscle composition showed that the association of the presence of Pre-RA with a larger decrease in muscle CSA over 2years was noticeable in the quadriceps, flexors, and sartorius muscle groups (P-values<0.05). Comparison of changes in total adipose tissue showed no difference between Pre-RA and control participants (estimate, 95% CI: 48.48mm2/2-year, -213.51 to 310.47, P-value=0.691). However, in the detailed analysis of thigh adiposity, Pre-RA presence was associated with a larger increase in Inter-MAT (estimate, 95% CI: 150.55mm2/2-year, 95.58 to 205.51, P-value<0.001). Preclinical rheumatoid arthritis is associated with a decrease in muscle cross-sectional area and an increase in intermuscular adipose tissue, similar to rheumatoid cachexia in clinical rheumatoid arthritis. These findings suggest the presence of cachexia in the preclinical phase of rheumatoid arthritis. Given that cachexia, which can exacerbate health outcomes, is potentially modifiable, this study emphasizes the importance of early identification of patients in their preclinical phase.

Predicting Rheumatoid Arthritis Development Using Hand Ultrasound and Machine Learning-A Two-Year Follow-Up Cohort Study.

The early diagnosis and treatment of rheumatoid arthritis (RA) are essential to prevent joint damage and enhance patient outcomes. Diagnosing RA in its early stages is challenging due to the nonspecific and variable clinical signs and symptoms. Our study aimed to identify the most predictive features of hand ultrasound (US) for RA development and assess the performance of machine learning models in diagnosing preclinical RA. We conducted a prospective cohort study with 326 adults who had experienced hand joint pain for less than 12 months and no clinical arthritis. We assessed the participants clinically and via hand US at baseline and followed them for 24 months. Clinical progression to RA was defined according to the ACR/EULAR criteria. Regression modeling and machine learning approaches were used to analyze the predictive US features. Of the 326 participants (45.10 ± 11.37 years/83% female), 123 (37.7%) developed clinical RA during follow-up. At baseline, 84.6% of the progressors had US synovitis, whereas 16.3% of the non-progressors did (p < 0.0001). Only 5.7% of the progressors had positive PD. Multivariate analysis revealed that the radiocarpal synovial thickness (OR = 39.8), PIP/MCP synovitis (OR = 68 and 39), and wrist effusion (OR = 12.56) on US significantly increased the odds of developing RA. ML confirmed these US features, along with the RF and anti-CCP levels, as the most important predictors of RA. Hand US can identify preclinical synovitis and determine the RA risk. The radiocarpal synovial thickness, PIP/MCP synovitis, wrist effusion, and RF and anti-CCP levels are associated with RA development.

The Role of Mesenchymal Stromal Cells in the Treatment of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterised by the formation of a hyperplastic pannus, as well as cartilage and bone damage. The pathogenesis of RA is complex and involves broad interactions between various cells present in the inflamed synovium, including fibroblast-like synoviocytes (FLSs), macrophages, and T cells, among others. Under inflammatory conditions, these cells are activated, further enhancing inflammatory responses and angiogenesis and promoting bone and cartilage degradation. Novel treatment methods for RA are greatly needed, and mesenchymal stromal cells (MSCs) have been suggested as a promising new regenerative and immunomodulatory treatment. In this paper, we present the interactions between MSCs and RA-FLSs, and macrophages and T cells, and summarise studies examining the use of MSCs in preclinical and clinical RA studies.

The Role of Mesenchymal Stem/Stromal Cells and Their Extracellular Vesicles in Rheumatoid Arthritis

There is presently no cure for the chronic inflammatory disease rheumatoid arthritis (RA), which affects the joints and other organs. Mesenchymal stem/stromal cells (MSCs) are adult stem cells that are widely studied in inflammatory diseases. Several studies have shown the therapeutic effects of MSCs in preclinical and clinical RA. However, there are a few concerns regarding the use of MSCs, such as immune rejection and malignancy. Since MSCs exert their potential effects in a paracrine manner, more attention has been paid to their extracellular vesicles (MSC-EVs). In the current study, we reviewed the application of MSCs and their EVs in RA. A better understanding of the mechanisms driving MSC and MSC-EVs in RA offers insight into possible treatment options for RA.

Gut microbiome and intestinal inflammation in preclinical stages of rheumatoid arthritis

BackgroundFaecal Prevotellaceae, and other microbes, have been associated with rheumatoid arthritis (RA) and preclinical RA. We have performed a quantitative microbiome profiling study in preclinical stages of RA.MethodsFirst-degree relatives of...

Tibialis Posterior Tenosynovitis as a First Presenting Feature of Pre-clinical Rheumatoid Arthritis: A Case Report and Literature Review

Tenosynovitis in Preclinical Rheumatoid Arthritis (RA) has been reported. The Tibialis posterior (TP) tendon is the second most commonly affected tendon in the foot and ankle in established RA, but in preclinical RA has not been reported. In this case report, we present a 27-year old lady from Dhading, Nepal, with Preclinical RA with first presentation with Tibialis posterior Tenosynovitis. She was anti-cyclic citrullinated Peptide (CCP) positive but had no arthralgia or morning stiffness. Initial treatment with Non-Steroidal anti-inflammatory drugs failed to alleviate her symptoms. Methotrexate helped improve her symptoms. Keywords: Methotrexate; Rheumatoid Arthritis; Tenosynovitis; Tibialis Posterior Dysfunction

Lipid profile and NT-proBNP changes from pre-clinical to established rheumatoid arthritis: A 12 years follow-up explorative study

ObjectivesThe aim of the current study was to explore the changes in lipid and NT-proBNP levels in rheumatoid arthritis (RA) patients through different phases of the disease: from the pre-clinical stage and RA onset up to the treatment phase with biological disease-modifying anti-rheumatic drugs (bDMARDS). MethodsThirty-eight consecutive patients, initially with arthralgia and rheumatoid factor and/or anti-citrullinated protein antibodies without arthritis, who later developed RA and eventually started treatment with bDMARDs, were included. Lipid spectrum and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured longitudinally from several months before diagnosis through treatment with bDMARDs. ResultsFrom baseline, C-reactive protein (CPR) initially increased sharply, decreasing with the start of biological treatment. Low-density lipoprotein-cholesterol (LDL-c) remained stable, high-density lipoprotein-cholesterol (HDL-c) increased, apolipoprotein A1 (ApoA1 and lipoprotein (a) (Lp(a)), and total cholesterol (TC)/HDL-c ratio and apolipoprotein B (ApoB) decreased during follow-up. NT-proBNP closely followed progression of CRP. TC, LDL-c, TC/HDL-c ratio, ApoA and ApoB inverse correlated with CRP, while Lp(a) positively correlated. HDL-c and triglycerides showed no correlation. ConclusionChanges in the lipid profile and NT-proBNP in RA patients seem to be related to inflammation, with changes reflecting an increase in CVD risk occurring along with rises in CRP levels. These changes seem to already be present at diagnosis, indicating the need for timely control of inflammation.

Performance of Anti-Carbamylated Protein Antibody Testing in the Routine Evaluation of Rheumatoid Arthritis from a Single Center.

Detection of anticyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factors (RF) in sera support the diagnosis of rheumatoid arthritis (RA); however, these markers are not detected in about 20% of RA patients. More recently, antibodies against carbamylated proteins (anti-CarP) have emerged with implications for preclinical RA diagnosis. The objective of this study was to assess the clinical performance of anti-CarP and correlate with disease severity in routine clinical practice. Retrospective chart review of 331 subjects submitted for RA panel serology: 136 clinically defined RA-positive and 195 RA-negative patients. Fifty additional individuals were recruited for healthy controls. Patients' sera were tested for anti-CCP, anti-CarP, and RF antibodies. Clinical performance characteristics were evaluated for anti-CarP individually and in combination with anti-CCP and RF. Documented erosions and synovitis were correlated with anti-CarP positivity. Anti-CarP had a clinical sensitivity and specificity of 27% and 94%, respectively, for established RA. This sensitivity was lower than anti-CCP (79%) and RF (85%). The specificity of anti-CarP was similar to anti-CCP (93%) and higher than RF (69%). Anti-CarP in combination with anti-CCP and RF increased specificity (100%) but decreased sensitivity (21%). There was no correlation of anti-CarP positivity with presence of bone erosions; however, there was an increase in anti-CarP positivity among patients with synovitis. Anti-CarP demonstrates high specificity in diagnosis of established RA but lacks clinical sensitivity. In combination, anti-CarP does not improve clinical performance of anti-CCP and RF but may be useful in anti-CCP negative patients and in identifying patients with more active disease.

Updates on Novel Treatments for Rheumatoid Arthritis

Chronic joint inflammation is a hallmark of the systemic inflammatory illness known as rheumatoid arthritis (RA), which ultimately causes severe disability and early death. Around 1% of people worldwide are affected by it, and women are 2-3 times more likely to be affected than males. Preclinical RA, genetic influences and environmental influences all have a role in the etiology of the illness. Since there is no recognized treatment for RA, achieving the lowest disease activity and, if possible, recovery remains the key goals of care. The literature on the various RA therapy options, their mechanisms of action, side effects and innovative drug delivery systems that are currently being used for medication administration are highlighted in this review, with non-steroidal anti-inflammatory drug delivery systems receiving the most attention. The most popular medications from each class are reviewed, including corticosteroids, non-steroidal anti-inflammatory medicines (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs) and biologics. Traditional medication therapy has various drawbacks, including inadequate bioavailability, first pass metabolism, gastrointestinal enzyme degradation, limited solubility and permeability, food interactions and toxicity. Innovative drug delivery technologies such as microspheres, nanoparticles, dendrimers, liposomes and others, hold great promise since they have been able to overcome the drawbacks of traditional drug delivery systems. The current review compares and contrasts numerous unique drug delivery methods that have been investigated for using anti-rheumatic medications, as well as the benefits of using these novel methods over traditional drug delivery methods.

Symposium 7

Pre-clinical rheumatoid arthritis (RA) is a phase of the disease that occurs before the characteristic symptoms and clinical manifestations of RA become evident. One key aspect of pre-clinical RA research has been the identification of biomarkers that can predict the development of RA in individuals who are at risk. Rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) are often detectable in the pre-clinical phase, sometimes years before clinical onset. These biomarkers, along with genetic and environmental factors contribute to the risk profile for RA development. Synovial biopsy, serum and peripheral blood cell characterization, magnetic resonance imaging (MRI) and ultrasound, have allowed researchers to capture subclinical joint inflammation in individuals who do not yet exhibit clinical symptoms. This has provided valuable insights into the progression of RA, as well as the potential for early intervention to prevent irreversible joint damage. Understanding the pathogenesis of pre-clinical RA has revealed the role of several initial pathways that are relevant for the onset of the disease, paving the way for new treatment intervention and new very early diagnostic strategies. Ongoing research will continue to refine our understanding of this phase of the disease and optimize strategies for its management.

Rheumatoid arthritis and the risk of postpartum psychiatric disorders: a Nordic population-based cohort study

BackgroundPostpartum psychiatric disorders (PPD) are common complications of childbirth. A common explanation for their development is that the psychological, hormonal, and immune changes associated with pregnancy and parturition may trigger psychiatric symptoms postpartum. Rheumatoid arthritis (RA) is characterized by abnormalities in the activity of the hypothalamic–pituitary–adrenal axis and of the immune system, but its association with PPD is unknown. We analyzed whether women with RA before childbirth have an increased risk of PPD.MethodsWe conducted a large population-based cohort study including mothers of singleton births in the Danish (1995–2015), Finnish (1997–2013), and Swedish Medical Birth Registers (2001–2013) (N = 3,516,849). We linked data from the Medical Birth Registers with data from several national socioeconomic and health registers. Exposure was defined as having a diagnosis of RA before childbirth, while the main outcome was a clinical diagnosis of psychiatric disorders 90 days postpartum. We analyzed the association between RA and PPD using Cox proportional hazard models, stratified by a personal history of psychiatric disorders.ResultsAmong women without a history of psychiatric disorders, the PPD incidence rate was 32.2 in the exposed and 19.5 per 1000 person-years in the unexposed group; women with RA had a higher risk of overall PPD than their unexposed counterparts [adjusted hazard ratio (HR) = 1.52, 95% confidence intervals (CI) 1.17 to 1.98]. Similar associations were also observed for postpartum depression (HR = 1.65, 95% CI 1.09 to 2.48) and other PPD (HR = 1.59, 95% CI 1.13 to 2.24). Among women with a history of psychiatric disorders, the incidence rate of overall PPD was 339.6 in the exposed and 346.6 per 1000 person-years in the unexposed group; RA was not associated with PPD. We observed similar associations between preclinical RA (RA diagnosed after childbirth) and PPD to those corresponding to clinical RA.ConclusionsRheumatoid arthritis was associated with an increased PPD risk in women without, but not in those with a psychiatric history. If our findings are confirmed in future studies, new mothers with RA may benefit from increased surveillance for new-onset psychiatric disorders postpartum.

Low-Intensity Physical Exercise Decreases Inflammation and Joint Damage in the Preclinical Phase of a Rheumatoid Arthritis Murine Model

Lifestyle modifications in preclinical Rheumatoid Arthritis (RA) could delay the ongoing pathogenic immune processes and potentially prevent its onset. Physical exercise (PE) benefits RA patients; however, its impact in reducing the risk of developing RA has scarcely been studied. The objective was to describe the effects of low-intensity PE applied at the disease's preclinical phase on the joints of DBA/1 mice with collagen-induced arthritis (CIA). Twelve mice with CIA were randomly distributed into two groups: the CIA-Ex group, which undertook treadmill PE, and the CIA-NoEx, which was not exercised. The effects of PE were evaluated through clinical, histological, transcriptomics, and immunodetection analyses in the mice's hind paws. The CIA-Ex group showed lower joint inflammation and damage and a decreased expression of RA-related genes (Tnf Il2, Il10, Il12a, IL23a, and Tgfb1) and signaling pathways (Cytokines, Chemokines, JAK-STAT, MAPK, NF-kappa B, TNF, and TGF-beta). TNF-α expression was decreased by PE in the inflamed joints. Low-intensity PE in pre-arthritic CIA reduced the severity through joint down-expression of proinflammatory genes and proteins. Knowledge on the underlying mechanisms of PE in preclinical arthritis and its impact on reducing the risk of developing RA is still needed.

Preclinical Rheumatoid Arthritis And Its Relationship With Changes In Thigh Muscle Quality

Preclinical Rheumatoid Arthritis And Its Relationship With Changes In Thigh Muscle Quality

Characterization of serum biomarkers and antibody responses against Prevotella spp. in preclinical and new-onset phase of rheumatic diseases.

The characterization of the influence of the microbiota on the development and drug responses during rheumatic diseases has intensified in recent years. The role of specific bacteria during disease development has become a central research question. Notably, several lines of evidence point to distinct microbes, e.g., Prevotella copri (P. copri) being targeted by antibodies in clinical phases of rheumatic diseases. In the present study, we compiled a broad collection of human serum samples from individuals at risk of developing RA, chronic RA patients as well as patients with new-onset of rheumatic diseases. We evaluated the presence of inflammatory biomarkers in our serum collection as well as serum antibody responses against novel, genetically distinct isolates of P.copri and several oral pathobionts. Our analysis revealed the presence of increased levels of inflammatory markers already in pre-clinical and new onset rheumatoid arthritis. However, antibody reactivity against the microbes did not differ between patient groups. Yet, we observed high variability between the different P.copri strains. We found total serum IgG levels to slightly correlate with IgG antibody responses against P.copri, but no relation between the latter and presence or prevalence of P.copri in the intestine. In conclusion, our work underlined the importance of strain-level characterization and its consideration during further investigations of host-microbiota interactions and the development of microbiome-based therapeutic approaches for treating rheumatic diseases.

Gut bacteriome, mycobiome and virome alterations in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic destructive autoimmune disease of the joints which causes significant pain, functional disability, and mortality. Although aberrant immune cell activation induced by the imbalance between T helper Th1/Th17 and Treg cells is implicated in the RA development, its etiopathogenesis remains unclear. The presence of mucosal inflammation and systemic IgA-isotype-autoantibodies (anti-citrullinated peptide antibodies and rheumatoid factor) in pre-clinical RA supports the mucosal origin hypothesis involving altered microbiota in disease development. The gut microbiota comprises diverse bacteria, fungal and viral components, which are critical in developing host immunity. Alterations in microbial abundance are known to exacerbate or attenuate immune responses in the gut microenvironment subsequently affecting the joints. Further, these changes can provide biomarkers for disease activity and outcome in RA. Most of the research till date has been focused on describing gut bacterial components in RA. Studies on gut mycobiome and virome components in RA are relatively new and burgeoning field. Given the paucity of mycobiome or virome specific studies in RA, this review, discusses the recent findings on alterations in gut bacterial, fungal, and viral components as well as their role in regulating the spectrum of immune-pathogenic events occurring in RA which might be explored in future as a potential therapeutic target. Further, we provide an overview on inter-kingdom interactions between bacteria, fungi, and viruses in RA. The current understanding on gut microbiota modulation for managing RA is also summarised.

Differential effects of periodontal microbiome on the rheumatoid factor induction during rheumatoid arthritis pathogenesis

Association between exposure to periodontal bacteria and development of autoantibodies related to rheumatoid arthritis (RA) has been widely accepted; however, direct causal relationship between periodontal bacteria and rheumatoid factor (RF) is currently not fully understood. We investigated whether periodontal bacteria could affect RF status. Patients with preclinical, new-onset, or chronic RA underwent periodontal examination, and investigation of subgingival microbiome via 16S rRNA sequencing. Degree of arthritis and RF induction was examined in collagen-induced arthritis (CIA) mice that were orally inoculated with different periodontal bacteria species. Subsequently, single-cell RNA sequencing analysis of the mouse spleen cells was performed. Patients with preclinical RA showed an increased abundance of the Porphyromonadacae family in the subgingival microbiome compared to those with new-onset or chronic RA, despite comparable periodontitis severity among them. Notably, a distinct subgingival microbial community was found between patients with high-positive RF and those with negative or low-positive RF (p=0.022). Oral infections with the periodontal pathogens P. gingivalis and Treponema denticola in CIA mice similarly enhanced arthritis score, but resulted in different levels of RF induction. Genes related to B cell receptor signaling, B cell proliferation, activation, and differentiation, and CD4+ T cell costimulation and cytokine production were involved in the differential induction of RF in mice exposed to different bacteria. In summary, periodontal microbiome might shape RF status by affecting the humoral immune response during RA pathogenesis.

A high-fiber diet synergizes with Prevotella copri and exacerbates rheumatoid arthritis.

Both preclinical and established rheumatoid arthritis (RA) patients display alterations in the gut microbiome. Prevotella spp. are preferentially enriched in a subset of RA patients. Here, we isolated a Prevotella strain, P. copri RA, from the feces of RA patients and showed that colonization of P. copri RA exacerbated arthritis in a collagen-induced arthritis (CIA) model. With the presence of P. copri RA colonization, a high-fiber diet exacerbated arthritis via microbial alterations and intestinal inflammation. Colonization of P. copri together with a high-fiber diet enabled the digestion of complex fiber, which led to the overproduction of organic acids, including fumarate, succinate and short-chain fatty acids. Succinate promoted proinflammatory responses in macrophages, and supplementation with succinate exacerbated arthritis in the CIA model. Our findings highlight the importance of dysbiosis when evaluating the effects of dietary interventions on RA pathogenesis and provide new insight into dietary interventions or microbiome modifications to improve RA management.