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.

Adiponectin in asthma: implications for phenotyping.

Asthma is a heterogeneous inflammatory airway disease, which exhibits multiple phenotypes, mainly defined by a combination of different clinical features. Asthma phenotypes include age at onset, smoking status, exacerbations frequency, and co-existence of obesity. Links between specific biological pathways and phenotypes are emerging. The genetic background together with detectable biomarkers could more accurately identify asthma phenotypes consistent with clinical-physiological characteristics and response to therapies. Several cross-sectional studies indicate a strict correlation between adipose tissue, obesity, and asthma suggesting that obesity is not only a risk factor for asthma but also a predictor of poor prognosis. Despite the strong clinical correlation between obesity and asthma, the underlying biological pathways have not been extensively investigated. Recently, a pivotal role for adiponectin has been recognized in physio-pathological conditions of lung. Adiponectin is expressed as a 247 residues long protein and secreted as oligomers of low, medium and high molecular weight. The larger oligomers seem to have a more pronounced insulinsensitizing, anti-atherogenic, and anti-inflammatory effects. Interestingly, the three receptors AdipoR1, AdipoR2, and Tcadherin mediating adiponectin activity are expressed on lung cells mediating adiponectin beneficial effects. Recently, different studies demonstrated the involvement of adiponectin in asthma since its levels and the expression of AdipoR1, AdipoR2 and T-cadherin are modulated in asthma patients and in asthma mouse models. In the present study, we review the literature reporting adiponectin impact on expression of specific clinical asthma phenotypes.