Increased levels of irisin in people with long-standing Type 1 diabetes.

BACKGROUND: Irisin stimulates browning of white adipose tissue and improves metabolic control in mice. Betatrophin, another recently described hormone, improves metabolic control in mice by inducing β-cell proliferation. In vitro, irisin stimulates the expression of betatrophin in rat adipocytes. There is a great interest in developing drugs that target or use these hormones for the treatment of obesity and diabetes. We have previously reported on increased levels of betatrophin in people with Type 1 diabetes, but the levels of irisin are currently unknown.

AIM: To characterize the levels of irisin in Type 1 diabetes and investigate a potential correlation with betatrophin.

METHODS: Irisin and betatrophin were measured by enzyme-linked immunosorbant assay (ELISA) in 45 individuals with Type 1 diabetes and in 25 healthy controls.

RESULTS: Irisin levels were increased in people with Type 1 diabetes, and especially in women. Negative correlations between irisin levels and age at onset of Type 1 diabetes and plasma triacylglycerol levels were observed. Interestingly, in women with Type 1 diabetes a negative correlation between irisin and insulin doses was also observed. When computing correlations for all study participants, a positive correlation between irisin and total betatrophin was observed, but not between irisin and full-length betatrophin.

CONCLUSION: We report on increased circulating levels of irisin in people with Type 1 diabetes, especially in women. For women with Type 1 diabetes, the levels of irisin correlated with lower insulin requirements. Further studies are clearly needed to determine the role of irisin in Type 1 diabetes.