Adiponectin profile and Irisin expression in Italian obese children: Association with insulin-resistance

Adiponectin (Acrp30), its high molecular weight (HMW) oligomers, and Irisin are molecules involved in several metabolic processes. To investigate if these cytokines could represent new metabolic markers, we evaluated the expression of Acrp30 and Irisin in serum of obese children from South Italy affected by different degrees of insulin resistance (IR). The anthropometric and metabolic features were evaluated in 27 obese children versus 13 age-matched controls. The expression of Acrp30, its pattern and Irisin were investigated by ELISA, western blotting and fast protein liquid chromatography. The HOMA index was significantly higher in obese children versus controls, and metabolic syndrome was more prevalent in obese children with elevated IR versus those with normal HOMA (38% vs 16%). Total Acrp30 and HMW oligomers were significantly lower in obese than in control children, and the difference was more pronounced in children with HOMA >3.4. In control and obese children, total Acrp30 and HMW oligomers were inversely related to HOMA (r-0.38, p 0.02; r-0.35, p 0.03). Irisin was significantly higher in obese than in control children, and was inversely correlated with Acrp30 and HMW (r-0.32, p 0.04; r-0.39, p 0.01). The inverse correlation of Acpr30 and HMW oligomers with HOMA indicates that Acpr30 is directly involved in IR status. Moreover, the inverse correlation between Irisin and Acrp30 and, more significantly, between Irisin and HMW oligomers suggests that the two cytokines are closely connected. The use of Acrp30, HMW oligomers and Irisin as predictive factors of IR in obese children remains to be further elucidated.