Endocrine Abstracts

Non-thyroidal-illness syndrome (NTIS) is present in chronic diseases and considered an adaptive mechanism. However oxidative stress is linked to NTIS in a vicious circle, due to deiodinases alteration and negative effects of low T3 on antioxidant levels or activity. Moreover there is a tissue-specific thyroid hormone transport, receptor binding and hormone metabolism. Muscle is one of the main targets of thyroid hormone; on the other hand, Irisin is a novel discovered myokine firstly identified for its ability to induce browning of white adipose tissue, increase energy expenditure and finally protect against insulin resistance.

Unconclusive data have been reported about the role of Irisin in chronic diseases such as chronic heart and renal failure; moreover, no correlation between Irisin and antioxidant status has been investigated. Therefore, we performed a case-control study with the primary end-point to evaluate Irisin levels in two models of NTIS, such as chronic heart failure and chronic kidney disease during haemodialytic treatment; the secondary end-point was the correlation with total antioxidant capacity in order to establish a possible role of Irisin in the modulation of antioxidant systems. Two groups of patients were selected. Group A included Chronic heart failure patients (n=18; Aged 70.22 ± 2.78 ys; BMI ± 27.75 ± 1.28 Kg/m²); Group B included Chronic Kideny Disease patients (n=29; Aged 67.03 ± 2.64; BMI 24.53 ± 1.01); Finally, 11 normal subjects have been assumed as controls. Irisin has been evaluated by ELISA method and Total Antioxidant (TAC) capacity by spectrophotometric method. Irisin was significantly higher in Group B vs A and controls (Mean ± SEM: 20.18 ± 0.61 ng/ml vs 2.77 ± 0.77 and 13.06 ± 0.56, respectively; P<0.05); a significant correlation between Irisin and TAC was observed only in group B.

These preliminary data suggest a possible role of Irisin in modulation of antioxidant systems in two chronic syndromes characterized by low T3 syndrome, but with differential pattern in the two models studied. Further studies are needed to confirm these preliminary observations. That can be the basis for a longitudinal investigation, to assess a prognostic role of Irisin evaluation and possible therapeutical implications