Characterisation of betatrophin concentrations in childhood and adolescent obesity and insulin resistance.

ABSTRACT

BACKGROUND AND OBJECTIVE: Betatrophin, a novel hormone, is correlated with insulin resistance and promotes pancreatic ß-cell growth in mice. The aim of this study was to determine circulating betatrophin levels in overweight or obese children and adolescents. METHODS: The following pairs of subjects were included (i) normal-weight healthy (n = 27) and overweight or obese (n = 28); (ii) non-insulin-resistant overweight or obese (n = 25) and insulin-resistant obese (n = 15); (iii) normal-weight males (n = 18) and females (n = 20); (4) 5 to 8 yr olds (n = 20) and 8 to 14 yr olds (n = 18). Circulating betatrophin levels were measured using enzyme-linked immunosorbent assay (ELISA). In addition, clinical data were recorded and anthropometrical measurements were performed. RESULTS: Circulating betatrophin levels were increased significantly in obese children and adolescents with insulin resistance (365.77 ± 30.86 pg/mL) compared with overweight or obese subjects without insulin resistance (274.25 ± 26.52 pg/mL; p < 0.05). However, no differences in betatrophin levels were seen between lean and overweight or obese children (323.18 ± 25.91 vs. 348.27 ± 18.91 pg/mL, respectively; p > 0.05). In the normal-weight cohort, males had higher serum betatrophin level than did females, and subjects <8 yr old had lower serum betatrophin levels compared with those >8 yr. Surprisingly, betatrophin concentrations were correlated negatively with body mass index (BMI), but not with the BMI Z-score, in non-insulin-resistant children and adolescents. CONCLUSIONS: These results demonstrated that circulating betatrophin levels were increased in insulin-resistant obese children or adolescents and might act as a potential biomarker of insulin resistance in these populations. Furthermore, serum betatrophin concentrations might vary during the development of children and adolescents, as well as between genders.