Plasma irisin is associated with insulin resistance in men (854.4)

Abstract

The hormone irisin has been described as increasing energy expenditure and improving glucose tolerance in mice, yet its potential role in humans remains controversial. Objective: We describe the association between circulating irisin and insulin resistance in men with wide‐ranging fitness levels and metabolic health. Methods: Fifty‐two men aged 34‐53 yrs from 4 groups were compared: sedentary non‐obese controls (BMI<25 kg/m2), sedentary obese (BMI>30 kg/m2), sedentary obese glucose intolerant, and non‐obese highly trained endurance active. All participants were evaluated for fitness (VO2max), anthropometric profile, circulating metabolic profile, insulin resistance (hyperinsulinemic‐euglycemic clamp), and baseline plasma irisin levels (EIA, Phoenix Pharamaceuticals, Inc.). Results: Baseline plasma irisin levels were significantly different between groups (ANOVA p=0.01), being lowest in trained men (1406±382 ng/mL) and highest in metabolically deteriorated glucose intolerant subjects (2040±505 ng/mL). Including all subjects, irisin levels were positively associated with percent body fat (r=0.445, p<0.01), and negatively associated with fitness (r=‐0.369, p<0.01) and insulin sensitivity (M/I, r=‐0.355, p<0.01). The strength of these associations was reduced and lost statistical significance when excluding the active individuals, except for that with insulin resistance, which was slightly increased (r=‐0.413, p<0.01). Conclusion: Plasma irisin levels are associated with decreased insulin sensitivity in men, but the association appears to be influenced by training status.Grant Funding Source: Supported by the CIHR and CRIUCPQ.