Background: 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).
Methods: 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.
Results: 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.
Conclusions: 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.