Abstract
BACKGROUND: Irisin is a recently identified exercise-induced hormone that stimulates the "browning" of the white adipose tissue, at least in mice. In chronic kidney disease (CKD) patients, irisin regulation is not fully understood, and little attention has been given to the effects of exercise on irisin levels in these patients. The purpose of this study was to assess the effects of high intensity exercise on irisin plasma levels in CKD patients under hemodialysis (HD). METHODS: Fifteen HD patients (5 men, 44.4 ± 15.1 years old) were studied and served as their own controls. High intensity (single session) intradialytic strength exercises consisted of three sets of ten repetitions with four different movements in both lower limbs during 30 minutes. Blood samples were collected on different days (exercise and non-exercise day) at exactly the same time (30 and 60 minutes after the start of dialysis session). Plasma irisin levels were measured by ELISA assay and anthropometric and biochemical parameters were evaluated. RESULTS: Irisin plasma levels were significantly reduced in both exercise day (125.0 ± 18.5 to 117.4 ± 15.0 ng/mL, p=0.02) and non-exercise day (121.5 ± 13.7 to 115.4 ± 17.2 ng/mL, p=0.02) after 60 minutes of dialysis. CONCLUSION: These data suggest that intense intradialytic strength exercise was unable to increase the circulating concentration of irisin in HD patients. Moreover, our data show that after one hour of dialysis session, irisin plasma levels may be reduced.