The Effect of Sleeve Gastrectomy on Oxidative Stress in Obesity

High concentrations of free radicals are present in the blood of obese patients. Free radicals are associated with endothelial dysfunction, diabetes, and neoplastic transformation, all conditions that are closely related to obesity. The purpose of our study was to determine whether bariatric surgery modifies the production of free radicals in obese patients. In total, 20 patients with morbid obesity, who were candidates for laparoscopic sleeve gastrectomy (SG), and 18 controls were enrolled in the study. Oxidative stress was studied in obese subjects before and after sleeve gastrectomy. The evaluation of oxidative stress was carried out on blood samples using electron paramagnetic resonance, a refined spectroscopic technique used to identify and quantify the major free radicals, such as ^•OH, O₂^•, ONOO^-, and NO. Oxidative stress was higher in subjects with morbid obesity prior to surgery, compared to the controls (CP• 9.9 ± 0.3 µM vs. 5.8 ± 0.2 µM). After SG, values decreased to levels comparable to those of controls (CP• 5.4 ± 0.2 µM). Further analysis identified O₂^• as the main free radical responsible for the oxidative stress. Obesity is associated with an increased blood concentration of free radicals. The normalization of free radicals after sleeve gastrectomy highlights another important benefit of this bariatric surgery technique.