Lower circulating irisin is associated with nonalcoholic fatty liver disease and type 2 diabetes

Irisin, a novel adipokine secreted by adipose tissue, is hypothesized to play a crucial role in metabolism. The objective of this study was to determine the plasma levels of irisin and adiponectin in patients with NAFLD (n=41), T2DM (n=41) and NAFLD with T2DM (NAFLD+T2DM) (n=40) in comparison with healthy subjects (n=40) and also to investigate the possible association of irisin levels with NAFLD and diabetes-related indices. The anthropometric and biochemical parameters were measured in all subjects. Plasma levels of irisin and adiponectin were measured by ELISA. The levels of irisin was significantly lower in NAFLD, T2DM and NAFLD+T2DM patients, compared to the controls (p<0.001). Irisin levels were negatively correlated with BMI, WHR, visceral fat, HOMA-IR, FBG, insulin, liver stiffness and liver enzymes. We also observed a positive correlation between plasma levels of adiponectin and irisin. Based on multiple stepwise linear regression, ALT (β [SE]=0 0.056 [0.012], p<0.001) and irisin concentrations (β [SE]=-1.672 [0.414], p<0.001) were two independent predictors for liver stiffness. Moreover, increased irisin was associated with reduce the risk of T2DM, NAFLD and NAFLD+T2DM. The receiver operating characteristic (ROC) curves analysis for diagnostic value of irisin circulating levels to differentiate between each condition also showed that the area under the curve were 0.78 for NAFLD, 0.8 forT2DM, and 0.86 for T2DM+NAFLD. It seems that the decreased circulating levels of irisin and adiponectin might be associated with T2DM and NAFLD.