Nitric oxide production is increased in severely obese children and related to markers of oxidative stress and inflammation

Objective: Nitric oxide (NO) is the major endothelium-derived relaxing factor. The aim of the present study was to evaluate NO synthesis and metabolism in severely obese children with different degrees of metabolic risk and to ascertain their relation with the parameters of oxidative stress and inflammation. Methods: The study involved 60 obese children evaluated with respect to metabolic risk factors (MRFs) (32 < 4 MRFs and 28 >= 4 MRFs) and 50 normal weight children between 7 and 14 years of age. Nutritional status was assessed by clinical and anthropometric examination. MRFs (serum lipid profile, insulin resistance indexes, blood pressure) in addition to uric acid, homocysteine, leptin, and inflammatory markers were measured. Plasma nitrite, nitrate and nitrotyrosine concentrations, and urinary nitrate were determined as markers of NO production and nitrosative stress. Malondialdehyde, 8-isoprostane F-2 alpha, and advanced oxidation protein products were analyzed in plasma to assess oxidative stress. Results: Compared with healthy controls, the obese children had significantly increased concentrations of markers of NO synthesis and nitrosative and oxidative stress that were correlated with each another. Increased NO production in obese children was associated with MRFs; plasma nitrate to waist circumference (r = 0.388, p = 0.003), uric acid (r = 0.404, p < 0.001), and tumor necrosis factor alpha. (r = 0.302, p = 0.021), and plasma nitrite to triglycerides (r = 0.432, p < 0.001). Conclusion: NO synthesis and nitrosative stress are increased in severely obese children and correlated with anthropometric parameters indicative of abdominal obesity, oxidative stress and inflammatory markers. (C) 2011 Elsevier Ireland Ltd. All rights reserved.