Angiopoietin-2 and soluble Tie-2 receptor plasma levels in children with obstructive sleep apnea and obesity

Objective: Obstructive sleep apnea (OSA) is a prevalent condition, especially in children with obesity, and is associated with increased risk for metabolic syndrome (MetS). Angiopoietins have been identified as potential biomarkers of endothelial dysfunction and MetS. In adults, angiopoietin-2 (Ang-2) and its soluble receptor (sTie-2) are associated with diabetes, hypertension, and obesity and could be increased in children with OSA and obesity, particularly those with evidence of cardiometabolic alterations. Methods: One hundred twenty-six children (7.4 ± 2.0 years) were consecutively recruited and underwent overnight polysomnography, as well as endothelial function and BMI z score assessments and a fasting blood draw the morning after the sleep study. In addition to lipid profile, glucose and insulin levels, and homeostatic model assessment of insulin resistance (HOMA-IR), Ang-2 and sTie-2 concentrations were determined. Results: Children with obesity and OSA had significantly elevated plasma Ang-2 and sTie-2 levels compared to corresponding controls with and without obesity. Furthermore, endothelial function (Tmax) and HOMA-IR were linearly and independently associated with Ang-2 and sTie-2 levels. In a small subset of children (n = 14), treatment of OSA by adenotonsillectomy resulted in reductions of Ang-2 and sTie-2 (P < 0.01). Conclusions: Ang-2 and sTie-2 plasma levels are increased in pediatric OSA and obesity, particularly when endothelial dysfunction or insulin resistance is detectable, and appear to decrease upon OSA treatment.