Improvement of microvascular endothelial dysfunction induced by exercise and diet is associated with microRNA-126 in obese adolescents

Objective: Microvascular endothelial dysfunction, which is at the early stage of atherosclerosis, precedes macrovascular endothelial dysfunction. The study is aimed to investigate the mechanism underlying the improvement of microvascular endothelial dysfunction by exercise and diet in obese adolescents. Methods: A quasi-randomized study was carried out with 2 cohorts: the experimental group (57 obese male adolescents; age: 15.38 +/- 2.82 years, BMI: 33.21 +/- 4.23 kg/m(2)) completed a 6-week exercise program with dietary intervention, and control group (10 normal weight adolescents; age: 15.38 +/- 2.82 years, BMI: 23.21 +/- 4.23 kg/m(2)) maintained sedentary. Clinical characteristics, circulating NO, ET-1 and microRNA-126 (miR-126) levels were measured before and after 6 weeks. The Reactive Hyperemia Index (RHI) was measured using EndoPAT-2000 system. Results: After 6-weeks intervention, obese adolescents' body circumferences and glucolipid metabolism are significantly improved. RHI (p < 0.01) and serum levels of NO/ET-1 (p < 0.01) are significantly increased, while microRNA-126 significantly decreased (p < 0.01). Delta MiR-126 were positive correlated with Delta BMI (r = 0.60, p < 0.01), Delta RHI (r = 0.69, p < 0.05), and Delta NO/ET-1 (r = 0.68, p < 0.05). Conclusions: Combination of exercise and diet control can effectively improve glycolipid metabolism of obese adolescents, and thus their microvascular endothelial function, which might be related to changes in serum miRNA-126.