Plasma Protein Carbonyl and Thiol Stress Before and After Laparoscopic Gastric Banding in Morbidly Obese Patients

Abstract

The aim of this study is to examine the relationship between oxidative plasma protein and thiol stress and weight loss after laparoscopic adjustable gastric banding (LAGB). Plasma protein carbonyl (PCO) concentration as a marker of protein oxidation, plasma thiol (P-SH) and erythrocyte glutathione concentration (GSH, major intracellular thiol), as an antioxidant and metabolic markers, such as Homeostatic Model Assessment - Insulin resistance (HOMA-IR), BMI and plasma lipids were determined in morbidly obese patients (n 22, mean age 34.7 +/- 11 years, BMI 48.4 +/- 6.4 kg/m2) at baseline and 1 and 6 months after operation. Baseline levels in patients were also compared with the levels in age-matched controls (n 20, BMI 21.3 +/- 1.8 kg/m2). Plasma PCO and thiols and erythrocyte GSH concentrations were determined spectrophotometrically. Plasma PCO were significantly higher and plasma and erythrocyte thiol concentrations were significantly lower in morbidly obese patients than in controls (for each comparison, P<0.01). BMI, plasma triglycerides and HOMA-IR were positively correlated with plasma PCO and negatively correlated with plasma P-SH and erythrocyte GSH (for each comparison, P<0.01). Plasma HDL-cholesterol levels were positively correlated with plasma erythrocyte GSH (r = 0.405, P<0.01) and negative correlated with plasma PCO (r = -0.273, P<0.01). One and 6 months after the LAGB operation, total weight loss was 13.2 +/- 6.3 and 35.5 +/- 7.5 kg, respectively. Plasma PCO concentrations were decreased and P-SH and erythrocyte GSH concentrations were elevated following weight loss (for each, P<0.01). Only plasma P-SH levels were restored to the control levels 6 months after LAGB. Obesity and insulin resistance appear to be associated with plasma protein oxidation and thiol concentrations. Protein and thiol oxidative stress was improved by weight loss after LAGB in the short-term.