Adipocytokines and Associations With Abnormal Body Composition in Rheumatoid Arthritis

The role of anti-citrullinated protein antibody in pathogenesis of RA

Rheumatoid arthritis (RA) is a common autoimmune rheumatic disease that causes chronic synovitis, bone erosion, and joint destruction. The autoantigens in RA include a wide array of posttranslational modified proteins, such as citrullinated proteins catalyzed by peptidyl arginine deiminase4a. Pathogenic anti-citrullinated protein antibodies (ACPAs) directed against a variety of citrullinated epitopes are abundant both in plasma and synovial fluid of RA patients. ACPAs play an important role in the onset and progression of RA. Intensive and extensive studies are being conducted to unveil the mechanisms of RA pathogenesis and evaluate the efficacy of some investigative drugs. In this review, we focus on the formation and pathogenic function of ACPAs.

Association Between the Quality of Life Domains with Anthropometric and Adiposity Indices in Rheumatoid Arthritis: A Cross-Sectional Study from a Single Centre in Erbil-Iraq

Objective

The aim of this study was to assess the association between the anthropometric/adiposity indices or ratios with the status of quality of life (QoL) in rheumatoid arthritis (RA) patients.

Methods

This study was carried out in the Rizgary Teaching Hospital in the Kurdistan Region of Iraq between 1st December 2021 and 31st March 2022. Seventy-five women with a mean value of 11.3 years' duration of disease were included in this study. The data relating to the demographic characteristics, disease activity score (DAS-28), biochemical measurements of the rheumatic profile, and anthropometric/adiposity indices and the ratios were included. The QoL of each patient was assessed using the WHOQOL-BREF.

Results

The mean ± SD of the age and duration of disease were 49.6± 12.0, and 11.3±8.4 year. 70 out of 75 (93.3%) patients have a DAS-28 score of >2.6. The median values of the transform scores of the WHOQOL-BREF domains were less than 50. There were significant inverse correlations between BMI, and waist-to-height ratio with physical activity (r = -0.167, p = 0.05, and r = -0.168, p = 0.05, respectively). Social domain was significantly and inversely correlated with waist-to-hip, estimated total body fat, and waist-adjusted weight index. A higher BMI and a lower hip index were associated significantly with a lower mean scores of physical health.

Conclusion

In RA patients, obesity is frequently observed. Over-weight and obese patients had a significantly lower mean score of physical health.

Lower body mass and lower adiposity are associated with differential responses to two treatment strategies for rheumatoid arthritis

PURPOSE

To determine if body mass index (BMI) and adipokine levels identify rheumatoid arthritis (RA) patients most likely to benefit from initiation of tumour necrosis factor inhibitors (TNFi) after methotrexate inadequate response.

METHODS

This is a secondary analysis of the Rheumatoid Arthritis Comparison of Active Treatments (RACAT) trial and the (TEAR) trial. Both studies compared treatment strategies starting with conventional disease-modifying anti-rheumatic drugs (DMARDs) (triple therapy) versus etanercept plus methotrexate. We compared response rates between TNFi and triple therapy among patients with different BMI. Adipokines were measured at enrolment and associations with treatment response were examined using regression, adjusting for age, sex, BMI and baseline disease activity.

RESULTS

In RACAT (n=306), participants who were normal/underweight were more likely to benefit from TNFi versus triple therapy, with greater change in Disease Activity Score in 28 and greater ACR20 response (ACR 20: 64% vs 23%, p=0.001). In contrast, overweight/obese participants had similar response to TNFi versus triple therapy (p-for-interaction=0.001). Similarly, but modest patterns were observed in TEAR (n=601; ACR20: 67% vs 52%, p=0.05). In RACAT, adipokine scores consistent with lower adiposity also predicted greater response to TNFi (ACR20: 58% vs 37%, p=0.01) with better model fit compared with BMI alone.

CONCLUSIONS

Lower BMI and evidence of lower adiposity based on adipokine profiles were associated with a superior response to TNFi compared with triple therapy. There was no difference between treatments among overweight/obese participants. The results support TNFi being a particularly important therapeutic among normal/underweight patients, with implications for clinical decisions and trial design.

Adipokines in Rheumatoid Arthritis: Emerging Biomarkers and Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic inflammatory disease manifested by joint involvement, extra-articular manifestations, and general symptoms. Adipose tissue, previously perceived as an inert energy storage organ, has been recognised as a significant contributor to RA pathophysiology. Adipokines modulate immune responses, inflammation, and metabolic pathways in RA. Although most adipokines have a pro-inflammatory and aggravating effect on RA, some could counteract this pathological process. The coexistence of RA and sarcopenic obesity (SO) has gained attention due to its impact on disease severity and outcomes. Sarcopenic obesity further contributes to the inflammatory milieu and metabolic disturbances. Recent research has highlighted the intricate crosstalk between adipose tissue and skeletal muscle, suggesting potential interactions between these tissues in RA. This review summarizes the roles of adipokines in RA, particularly in inflammation, immune modulation, and joint destruction. In addition, it explores the emerging role of adipomyokines, specifically irisin and myostatin, in the pathogenesis of RA and their potential as therapeutic targets. We discuss the therapeutic implications of targeting adipokines and adipomyokines in RA management and highlight the challenges and future directions for research in this field.

Obesity, Adipokines, and Chronic and Persistent Pain in Rheumatoid Arthritis

We aimed to determine whether adipokines are associated with pain and polysymptomatic distress in patients with rheumatoid arthritis (RA) over time in a large patient registry. The cohort study was conducted in a subset of Forward; a patient-based multi-disease, multipurpose rheumatic disease registry with patients enrolled from community-based rheumatology practices across the U.S. Adipokines (adiponectin, leptin, and fibroblast growth factor[FGF]-21) were measured on stored serum as part of a multi-analyte panel. Body mass index (BMI), pain, polysymptomatic distress, and other patient-reported outcomes (PROs) were reported on biannual questionnaires. Linear regression was used to evaluate independent associations between BMI, adipokines, and PROs. Cox proportional hazards models evaluated independent associations between adipokines and clinically meaningful changes in pain over time (change in numerical rating>1.1 [range 0-10], sustained over 1 year). Among 645 patients included in these analyses, there were significant differences in RA characteristics, comorbidity, PROs, and adipokines across obesity categories. Of note, severely obese patients were more likely to experience greater pain, polysymptomatic distress, and fatigue. Patients with higher FGF-21 levels had higher pain and polysymptomatic stress at baseline, were more likely to use opioids, and were more likely to have sustained worsening pain over time [HR (per 1 SD) (95% CI): 1.22 (1.02,1.46) P = .03] independent of BMI. Obesity and elevated levels of FGF-21 are associated with pain and polysymptomatic distress in RA. Elevated FGF-21 levels may help identify those at risk of worsening pain trajectories over time, independent of BMI. PERSPECTIVE: This study characterizes the relationship between severe obesity and pain and polysymptomatic distress in patients with rheumatoid arthritis and demonstrates that the adipocytokine fibroblast growth factor-21 is independently associated with pain and predicts a worsening trajectory over time. Further mechanistic studies are needed.

Circulating Adipokines and Associations With Incident Cardiovascular Disease in Rheumatoid Arthritis

OBJECTIVE

To assess whether circulating levels of adiponectin, leptin, and fibroblast growth factor 21 (FGF-21) are associated with incident cardiovascular disease (CVD) in rheumatoid arthritis (RA).

METHODS

Adipokines were measured using banked enrollment serum from patients with RA and dichotomized above/below the median value. Incident CVD events (coronary artery disease [CAD], stroke, heart failure [HF] hospitalization, venous thromboembolism, CVD-related deaths) were identified using administrative data and the National Death Index. Covariates were derived from medical record, biorepository, and registry databases. Multivariable Cox models were generated to quantify associations between adipokine concentrations and CVD incidence. Five-year incidence rates were predicted.

RESULTS

Among 2,598 participants, 639 (25%) had at least 1 CVD event over 19,585 patient-years of follow-up. High adiponectin levels were independently associated with HF hospitalization (hazard ratio [HR] 1.39 [95% confidence interval (95% CI) 1.07-1.79], P = 0.01) and CVD-related death (HR 1.49 [95% CI 1.16-1.92], P = 0.002) but not with other CVD events. High leptin was independently associated with CVD-related death (HR 1.44 [95% CI 1.05-1.97], P = 0.02). High FGF-21 levels were independently associated with lower rates of CAD (HR 0.75 [95% CI 0.58-0.97], P = 0.03). In subgroup analyses, associations between high adiponectin and leptin levels with CVD-related death were driven by strong associations in nonobese patients.

CONCLUSION

Adipokines are associated with HF hospitalization and CVD-related death in patients with RA, with stronger associations in nonobese participants. These findings suggest that adipokines effectively predict clinically important outcomes in RA perhaps through an association with body composition and metabolic health. Further study is needed to determine whether adipokine measures might augment existing tools to identify RA patients at increased risk of CVD.

Muscle mass loss is associated with physical dysfunction in patients with early rheumatoid arthritis

Background

Muscle mass loss is common in long-standing rheumatoid arthritis (RA). The aim was to explore the prevalence and effects of RA disease characteristics in patients with early RA.

Methods

This cross-sectional study was carried out based on a Chinese RA cohort and control subjects. The body composition (BC) was assessed using bioelectric impedance analysis. Myopenia was defined by an appendicular skeletal muscle mass index of ≤ 7.0 kg/m² in men and ≤ 5.7 kg/m² in women. Physical dysfunction was defined as a health assessment questionnaire disability index > 1. Propensity score matching was performed to balance age and gender differences among patients with early RA (disease duration ≤ 12 months) and established RA, and controls (with 1:3:3 matching).

Results

In total, 2017 controls and 1,008 patients with RA were recruited for this study. Among the patients with RA, there were 190 (18.8%) patients with early RA, with a median disease duration of 7 (4, 11) months. The matched patients with early RA (n = 160) showed a higher prevalence of myopenia than the matched controls (41.3 vs. 15.8%, P < 0.0167), but no difference was found in the matched patients with established RA (41.3 vs. 50.4%, P > 0.0167). Compared with the patients with established RA, the patients with early RA exhibited higher disease activity scores [disease activity score in 28 joints with four variables including C-reactive protein (DAS28-CRP): median 4.76 vs. 3.93, P < 0.001] and a higher prevalence of physical dysfunction (26.3 vs. 19.4%, P = 0.035). In the patients with early RA, patients with myopenia showed a higher prevalence of physical dysfunction than those without myopenia (41.3 vs. 15.5%, P < 0.001), among which walking and common daily activities were the most involved subdimensions. Multivariate logistic regression analysis showed that DAS28-CRP was positively associated with myopenia [adjusted odds ratio (AOR) 1.558, 95% CI (1.138-2.132)], and myopenia [AOR 2.983, 95% CI (1.192-7.465)] was independently associated with physical dysfunction in the patients with early RA.

Conclusion

Our data indicate the importance of early detection of muscle involvement in the early stage of RA and imply the significance of early aggressive control of disease activity for the prevention of myopenia and physical dysfunction in patients with early RA. Our study provides a new perspective on RA management.

Association between Plasma FGF21 Levels and Body Composition in Patients with Gastric Cancer

BACKGROUND

Accumulating evidence has suggested that Fibroblast growth factor 21 (FGF21) plays an important role in metabolic diseases. This study aimed to investigate the relationship between plasma FGF21 levels and body composition parameters in gastric cancer (GC) patients.

METHODS

This study was cross-sectional based on a prospective cohort of GC patients in a single center. Computer tomography (CT) and bioelectrical impedance analysis (BIA) were used to estimate skeletal muscle and adipose tissue mass. Blood samples were collected and plasma concentrations of FGF21 were measured by ELISA. Spearman's rank correlation test and logistic regression analysis were performed to assess associations between plasma FGF21 levels and these body composition parameters.

RESULTS

A total of 66 GC patients were enrolled in this study. Plasma FGF21 levels were significantly higher in women compared with men. The plasma FGF21 levels were positively correlated with fat mass index (FMI), fat mass percentage (FM%), and subcutaneous adipose tissue index (SATI). Furthermore, after adjustment for confounders, the lower plasma FGF21 levels were remain associated with increased odds for low SATI.

CONCLUSIONS

Plasma FGF21 levels were positively associated with FMI, FM%, and SATI in GC patients, suggesting a potential mechanistic link between FGF21 and subcutaneous adipose tissue in GC.

Perivascular adipose tissue in autoimmune rheumatic diseases

Perivascular adipose tissue (PVAT) resides at the outermost boundary of the vascular wall, surrounding most conduit blood vessels, except for the cerebral vessels, in humans. A growing body of evidence suggests that inflammation localized within PVAT may contribute to the pathogenesis of cardiovascular disease (CVD). Patients with autoimmune rheumatic diseases (ARDs), e.g., systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), psoriasis, etc., exhibit heightened systemic inflammation and are at increased risk for CVD. Data from clinical studies in patients with ARDs support a linkage between dysfunctional adipose tissue, and PVAT in particular, in disease pathogenesis. Here, we review the data linking PVAT to the pathogenesis of CVD in patients with ARDs, focusing on the role of novel PVAT imaging techniques in defining disease risk and responses to biological therapies.

Adipocytokines and achievement of low disease activity in rheumatoid arthritis

PURPOSE

To determine if adipocytokines are independently associated with the achievement of low disease activity (LDA) over long-term follow-up in a large rheumatoid arthritis (RA) registry.

METHODS

This cohort study evaluated adults with RA from the Veteran's Affairs RA Registry. Adipocytokines (adiponectin, leptin, and fibroblast growth factor [FGF]-21) and inflammatory cytokines were measured as part of a multi-analyte panel on banked serum from enrollment. Covariates were derived from medical record, biorepository, and registry databases. Multivariable Cox proportional hazard models evaluated associations between adipocytokines and rates of 1) DAS28 LDA and remission, 2) individual Boolean remission criteria and 3) initiation of a new bDMARD or tsDMARD.

RESULTS

There were 1,276 participants with a DAS28 >3.2 at enrollment. Of these, 827 achieved LDA and 598 achieved remission over 2,287 and 4,096 person-years, respectively. Patients in the highest quartile of adiponectin had lower rates LDA before and after adjustment [aHR Q4: 0.68 (0.53,0.87) p<0.001]. Those in the highest quartile of leptin and FGF-21 also had lower rates of LDA. Higher quartiles of adipocytokines were also associated with lower rates of achieving a low patient/evaluator global scores and low tender joint counts. Among 1,236 biologic-naïve participants, values above the median for adiponectin [HR: 1.67 (1.23,1.26) p = 0.001] and FGF-21 [HR: 1.27 (1.09,1.47) p = 0.002] were associated with a greater likelihood of initiating a b/tsDMARD.

CONCLUSIONS

Adipocytokines may serve as prognostic biomarkers of a more severe RA disease course. Additional study is needed to determine whether adipocytokines are phenotypic markers or whether they actively promote disease progression.

Organokines in Rheumatoid Arthritis: A Critical Review

Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily affects the joints. Organokines can produce beneficial or harmful effects in this condition. Among RA patients, organokines have been associated with increased inflammation and cartilage degradation due to augmented cytokines and metalloproteinases production, respectively. This study aimed to perform a review to investigate the role of adipokines, osteokines, myokines, and hepatokines on RA progression. PubMed, Embase, Google Scholar, and Cochrane were searched, and 18 studies were selected, comprising more than 17,000 RA patients. Changes in the pattern of organokines secretion were identified, and these could directly or indirectly contribute to aggravating RA, promoting articular alterations, and predicting the disease activity. In addition, organokines have been implicated in higher radiographic damage, immune dysregulation, and angiogenesis. These can also act as RA potent regulators of cells proliferation, differentiation, and apoptosis, controlling osteoclasts, chondrocytes, and fibroblasts as well as immune cells chemotaxis to RA sites. Although much is already known, much more is still unknown, principally about the roles of organokines in the occurrence of RA extra-articular manifestations.

Adiponectin Is a Component of the Inflammatory Cascade in Rheumatoid Arthritis

Adiponectin is a secretory protein of adipocytes that plays an important role in pathological processes by participation in modulating the immune and inflammatory responses. The pro-inflammatory effect of adiponectin is observed in rheumatoid arthritis (RA). In this study, we examined adiponectin plasma levels and the expression of adiponectin in bone marrow tissue samples, synovium samples, and infrapatellar fat pad samples from patients with osteoarthritis (OA) and RA. Additionally we examined the expression of adiponectin receptors AdipoR1 and AdipoR2 in synovium samples and infrapatellar fat pad samples from patients with OA and RA. We also assessed the correlations between adiponectin plasma concentrations, adiponectin expression in bone marrow, synovium, infrapatellar fat pad, and plasma levels of selected cytokines. We found increased expression of adiponectin in synovium samples and infrapatellar fat pad samples from patients with RA as compared to patients with OA. There were no statistically significant differences of adiponectin plasma levels and adiponectin expression in bone marrow tissue samples between OA and RA patients. There were no differences in the expression of AdipoR1 and AdipoR2 at the mRNA level in synovial tissue and the infrapatellar fat pad between RA and OA patients. However, in immunohistochemical analysis in samples of the synovial membrane from RA patients, we observed very strong expression of adiponectin in intima cells, macrophages, and subintimal fibroblasts, such as synoviocytes, vs. strong expression in OA samples. Very strong expression of adiponectin was also noted in adipocytes of Hoffa’s fat pad of RA patients. Expression of AdipoR1 was stronger in RA tissue samples, while AdipoR2 expression was very similar in both RA and OA samples. Our results showed increased adiponectin expression in the synovial membrane and Hoffa’s pad in RA patients compared to that of OA patients. However, there were no differences in plasma adiponectin concentrations and its expression in bone marrow. The results suggest that adiponectin is a component of the inflammatory cascade that is present in RA. Pro-inflammatory factors enhance the expression of adiponectin, especially in joint tissues—the synovial membrane and Hoffa’s fat pad. In turn, adiponectin also increases the expression of further pro-inflammatory mediators.

Elevations in adipocytokines and mortality in rheumatoid arthritis

OBJECTIVES

This study assessed whether circulating levels of adiponectin and leptin are associated with higher mortality in patients with RA.

METHODS

Participants were adults from the Veterans Affairs RA Registry. Adipokines and inflammatory cytokines were measured as part of a multi-analyte panel on banked serum at enrolment. Dates and causes of death were derived from the Corporate Data Warehouse and the National Death Index. Covariates were derived from medical record, biorepository and registry databases. Multivariable Cox proportional hazard models evaluated associations between biomarkers and all-cause and cause-specific mortality.

RESULTS

A total of 2583 participants were included. Higher adiponectin levels were associated with older age, male sex, white race, lower BMI, autoantibody seropositivity, radiographic damage, longer disease duration, prednisone use and osteoporosis. Higher adiponectin concentrations were also associated with higher levels of inflammatory cytokines but not higher disease activity at enrolment. Leptin was primarily associated with greater BMI and comorbidity. The highest quartile of adiponectin (vs lowest quartile) was associated with higher all-cause mortality [hazard ratio (HR): 1.46 (95% CI: 1.11, 1.93), P = 0.009] and higher cardiovascular mortality [HR: 1.85 (95% CI: 1.24, 2.75), P = 0.003], after accounting for covariates. Higher leptin levels were also associated with greater all-cause and cancer mortality.

CONCLUSIONS

Elevations in adipokines are associated with age, BMI, comorbidity and severe disease features in RA and independently predict early death. Associations between adiponectin and inflammatory cytokines support the hypothesis that chronic subclinical inflammation promotes metabolic changes that drive elevations in adipokines and yield adverse health outcomes.