Persistence of oxidative stress after heart transplantation:: A comparative study of patients with heart transplant versus chronic stable heart failure

Introduction and objective. Chronic heart failure (CHF) is associated with oxidative stress. Heart transplantation, an important therapeutic alternative in these patients, could reduce oxidative stress by improving cardiac function. Our aim was to evaluate post-heart transplantation oxidative stress. Patients and method. We studied three experimental groups: a) heart transplant recipients without evidence of rejection (n = 11); b) NYHA class III CHF patients (n = 19), and c) healthy control subjects (n = 14). Oxidative stress was assessed by measuring plasma malondialdehyde levels (MDA), and determining the enzymatic activities of glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD). Results. The demographic characteristics of the three groups were similar. Mean time from transplantation was 20.0 +/- 4.8 months. Mean MDA plasma levels in heart transplantation and CHF patients were significantly higher than in normal subjects (3.35 +/- 0.8; 3.27 +/-1.7 y 0.9 +/- 0.3 muM, respectively). GSH-Px activity increased after transplantation compared to control subjects (0.40 +/- 0.06 and 0.33 +/- 0.05 U/g Hb, respectively), but not the CHF group. A significant decrease in SOD activity was found in the heart transplant vs. CHF group (0.44 +/- 0.1 vs. 0.87 +/- 0.6 U/mg Hb). There were no differences in CAT values between heart transplant and CHF patients. Conclusion. These findings demonstrated the presence of permanent oxidative stress in patients who have undergone heart transplantation, characterized by an increase in MDA and a decrease in SOD activity, despite an increase in GSH-Px activity.