Myostatin is a cytokine produced and released by myocytes that might have an outstanding role not only in muscle wasting during cachexia but also in inflammation. Herein we explore the association between myostatin levels and inflammatory parameters in rheumatoid arthritis (RA). One hundred twenty-seven women without rheumatic diseases and 84 women with a diagnosis of RA were assessed in a cross-sectional study. Outcomes reflecting the activity of the arthritis including Disease Activity Score (DAS28-ESR) and impairment in functioning by the Health Assessment Questionnaire-Disability Index were assessed in RA. We obtained Skeletal muscle mass index (SMI), fat-free mass index (FFMI), and fat mass index using dual-energy x-ray absorptiometry. Serum myostatin was determined by enzyme-linked immunosorbent assay. Myostatin levels were correlated with disease activity and parameters of muscle mass. The SMI was lower and concentration of myostatin was higher in RA patients than in controls (P = .008 and P < .001, respectively). Myostatin significantly positively correlated with C-reactive protein (rho = 0.48, P < .001), erythrocyte sedimentation rate (rho  = 0.28, P = .009), and DAS28-ESR (rho = 0.22, P  = .04), and negatively correlated with SMI (rho = −0.29, P = .008), (FFMI) (rho = −0.24, P = .027). In the multivariate logistic regression analysis, levels of myostatin remained associated with disease activity in RA (P = .027). In our study, myostatin was associated with disease activity in RA patients, suggesting a mechanistic link between myostatin, muscle wasting and inflammation in RA.

Purpose: The increase of visceral abdominal fat (VAF) and oxidative stress (OS) are independent predictors for cardiovascular risk. This study aimed to determine the association of VAF with proinflammatory cytokines, oxidants, antioxidants, and oxidative damage to DNA in subjects with normal weight, overweight, and obesity. Patients and Methods: A cross-sectional study that included 21 men and 71 women who attended for a medical check-up was conducted. Dual-energy X-ray absorptiometry (DXA) was used to measure the VAF volume. ELISA and colorimetric techniques were used for chemical analysis.Results: Low activity of superoxide dismutase (SOD) was found in overweight and obese subjects compared to the normal weight group (p=0.005). In contrast, the activity of glutathione peroxidase (GPx) was higher in the overweight and obesity groups compared to the normal weight subjects (p=0.017). The total antioxidant capacity (TAC) was also increased in the overweight group compared to the normal weight group (p=0.04). According to the volume of VAF, the levels of tumor necrosis factor alfa and interleukin 6 showed no differences between subjects with normal and high VAF. Subjects with high VAF show higher levels of 8-isoprostans compared to normal VAF group (p=0.039). Less concentration of 8-oxoguanine-DNA-N-glycosylase-1 (hOGG1) was found in the high VAF group (p=0.032) compared to the normal VAF subjects. VAF was positively correlated with lipoperoxides (LPO) (r=0.27, p<0.05) and 8-isoprostanes (r=0.25, p<0.05). We also found correlations between oxidative stress markers and anthropometric ratios for intra-abdominal fat. The waist-hip ratio was positively correlated with LPO (r=0.30, p<0.05) and TAC (r=0.24, p<0.05). Conclusion: These findings suggest that the predominantly oxidative damage associated with VAF in overweight or obesity is lipoperoxidation and oxidative DNA damage. Alterations in endogenous antioxidant defenses may not be linked to the amount of VAF.

Background. Neuropeptide Y (NPY) is a sympathetic neurotransmitter with effects on the regulation of inflammatory cells. The role of NPY on autoimmune inflammatory diseases such as rheumatoid arthritis (RA) is not completely understood. Therefore, we evaluate if NPY levels are markers of disease activity in RA and if there is a correlation between NPY levels and tumor necrosis factor-alpha (TNF-α), leptin, and interleukin 6 (IL-6) levels. Methods. Cross-sectional design, including 108 women with RA. We assessed disease activity by DAS28-ESR (considering active disease a score of ≥2.6). Serum NPY levels and anti-CCP2 antibody, TNF-α, IL-6, and leptin levels were quantified (ELISA). Results. Sixty-eight RA had an active disease (RA-active), and 40 were in remission (RA-remission). RA-active patients had higher NPY levels vs. RA-remission (22.8±13.6 vs. 17.8±10.3; p=0.04). NPY levels correlated with increased TNF-α levels (r=0.32, p=0.001). Leptin or IL-6 did not correlate with NPY levels. In the logistic regression analysis, NPY increased the risk of disease activity (OR: 1.04, 95% CI 1.006-1.09, and p=0.03). Conclusion. Higher NPY levels are an independent marker of disease activity in RA. This study encourages the quantification of NPY levels as a surrogate marker for RA-active. Future studies evaluating the role of NPY levels interacting with other proinflammatory cytokines are required.

Introduction: Controversies exist regarding the relationship between body fat and disease activity in patients with rheumatoid arthritis. The evaluation of the disease is critical for establishing treatment and prognosis. Fat mass could be a predictive factor for poor prognosis in rheumatoid arthritis because of its association with low- and high-grade inflammation. Objective: To evaluate the correlation between fat mass values and disease activity in patients with rheumatoid arthritis. Materials and methods: This was a cross-sectional study. Eighty female patients diagnosed with rheumatoid arthritis (American College of Rheumatology of 1987) were evaluated. For each one, the evaluation determined fat mass using bioelectrical impedance analysis and disease activity using the Disease Activity Score on 28 joints (DAS28). Results: The mean age was 59.11 ± 9.92 years, with an average disease duration of 14.13 ± 10.13 years; 85% of patients showed a high body fat percentage. Pearson’s correlation between DAS28 values and fat mass was r = 0.035 ( p = 0.76). Conclusion: The levels of DAS28 showed no correlation with fat mass percentage. Further studies are required to clarify the factors that can modify these levels.

Background Low muscle mass (myopenia) is frequent in rheumatoid arthritis (RA) patients with a long-disease duration. Although, the use of combined therapy with conventional synthetic DMARDs (csDMARDs) is one of the main strategies observed in these patients; there is a lack of information if the failure to these therapies increases the risk of myopenia. Objective: To evaluate whether the treatment failure to combined therapy with conventional synthetic DMARDs is an independent risk factor for low skeletal muscle mass in women with RA. Methods This cross-sectional study compared 277 women with RA (cases) and 237 women from non-rheumatic population (controls). In RA patients, we assessed clinical, epidemiological, and therapeutic variables (identifying treatment failure to combined therapy with csDMARDs. The skeletal muscle index (SMI) was estimated by DXA. Low skeletal muscle mass was defined as SMI<5.45 kg/m2. Multivariate logistic regression analyses were used to a) evaluate whether RA is an independent risk factor of myopenia in comparison with non-rheumatic population and b) identify if treatment failure with csDMARDs is an independent risk factor of myopenia in RA. Results RA patients had a higher prevalence of low skeletal muscle mass than controls (27.8% vs. 15.6%, p=0.001). After adjusting for other factors, RA patients had higher risk of low skeletal muscle mass than controls (OR: 2.7, 95%CI:1.7 to 4.5). Risk factors of low muscle mass in RA patients; were: menopause (OR: 2.3, 95%CI: 1.2 to 4.6, p=0.02) and a failure to combined therapy with csDMARDs (OR: 2.4, 95%CI: 1.10 to 5.81, p=0.03). Conclusions Rheumatoid arthritis is associated with an increased risk of myopenia. Treatment Failure with conventional-synthetic DMARDs constitutes a strong risk factor for deteriorated skeletal muscle mass.