FNDC5 and metabolic disease: Subsequent studies have shown that irisin is involved in obesity, cardiovascular diseases, telomere length and ageing, and hippocampal neurogenesis.14 Moreover, a recent study verified that irisin can directly bind to the αv class of integrin receptors in osteocytes.19 Previous studies have demonstrated that gut barrier dysfunction after gut IR is mainly caused by metabolic disorders and destruction of enterocytes, which can benefit from exercise.30, 31 However, the effects of irisin on the intestinal barrier have not been elucidated to date.