Irisin, a novel myokine is an independent predictor for sarcopenia and carotid atherosclerosis in dialysis patients

Objective: In end-stage renal disease, deleterious effect of sarcopenia on cardiovascular disease has been explained mainly by chronic inflammation. However, evidence emerged that skeletal muscles mediate their protective effect against sarcopenia by secreting myokines. Therefore, we sought to investigate the effect of irisin, a recently introduced myokine, on the association between sarcopenia and cardiovascular disease in peritoneal dialysis (PD) patients. Methods: Serum irisin concentrations were assessed by enzyme-linked immunosorbent assay in 102 prevalent PD patients and 35 age- and sex-matched controls. To determine sarcopenia and cardiovascular disease, anthropometric indices including mid-arm muscle circumference (MAMC) and carotid intima-media thickness (cIMT) were measured. Results: Serum irisin concentrations were significantly lower in PD patients than in controls (184.2 +/- 88.0 vs. 457.2 +/- 105.5 ng/mL, P < 0.001). In PD patients, univariate linear regression analysis showed that serum irisin was positively correlated with MAMC and thigh circumference, but negatively correlated with residual renal function and cIMT. Multivariate analysis revealed that MAMC (per 1 cm increase, B = 8.78, 95% confidence interval [CI] = 0.77-16.79, P = 0.03) had an independent association with serum irisin. In addition, serum irisin was a significant independent predictor for carotid atherosclerosis even after adjustment for high-sensitivity C-reactive protein in PD patients (per 1 g/mL increase, odds ratio = 0.990, 95% CI = 0.982-0.997, P = 0.007). Conclusion: This study demonstrated that serum irisin was significantly associated with sarcopenia and carotid atherosclerosis in PD patients. Additional studies to provide a confirmation and examine possible mechanisms are warranted. (C) 2015 Elsevier Ireland Ltd. All rights reserved.