Increased circulating levels of irisin are associated with cardiovascular risk factors in subjects with acromegaly.

Abstract

Irisin, a peptide secreted from muscle and adipose tissues, is associated with insulin resistance as well as metabolic and cardiovascular diseases. Acromegaly is a rare disorder caused by overproduction of growth hormone (GH) and is associated with functional and structural differentiation of adipose and muscle tissues. Acromegalic subjects are also at risk of vascular diseases and metabolic dysfunctions. We aimed to determine the altered levels of irisin in subjects with active acromegaly and controlled acromegaly and in controls, and to ascertain whether there is an association between irisin and hormonal and cardiometabolic parameters. We enrolled 40 subjects with active acromegaly, 30 subjects with controlled acromegaly, and 40 control subjects of matched age, gender, BMI, and occurrence of hypertension, diabetes, and metabolic syndrome distribution in the present cross-sectional study. Hormonal and metabolic parameters, carotid intima media thickness (cIMT), and epicardial fat thickness (EFT) of the subjects were evaluated. Irisin levels were measured using ELISA. Circulating levels of irisin were significantly higher in acromegalic subjects compared to both controlled acromegalic subjects and controls. Moreover, irisin levels were elevated in controlled acromegalic subjects compared to controls. Irisin displayed a positive correlation with insulin resistance, cIMT, EFT, BMI, GH, and insulin-like growth factor (IGF-1) in acromegalic subjects. Irisin levels were independently associated with cIMT and EFT according to multiple regression analyses. There was an independent relationship between irisin and IGF-1. Elevated irisin levels in acromegalic subjects were associated with cIMT and EFT, suggesting that irisin is a surrogate marker for cardiovascular risk in acromegalic subjects.