CONICET | Buscador de Institutos y Recursos Humanos

Epicardial adipose tissue (EAT) is a visceral fat adjacent to coronary arteries and the myocardium. EAT is considered an endocrine organ, and its volume an independent risk factor for coronary artery disease (CAD). Catalase (CAT) and Superoxide dismutase (SOD) are antioxidant enzymes that protect cells against potentially harmful effects of reactive oxygen species. Until now, there is no evidence about the behavior of these enzymes in EAT from patients with CAD. Aim: to evaluate CAT and SOD activity in EAT from patients with CAD and their relationship with insulin-resistance (IR). Subjects and Methods: Peripheral venous blood, EAT and subcutaneous adipose tissue (SAT) were obtained from patients undergoing heart surgery for coronary artery bypass graft (CAD, N=10) or valve replacement (No CAD, N=10). In serum glucose, lipids and lipoproteins profile was assessed. In EAT and SAT, CAT activity was evaluated by decomposition of H2O2 at 240 nm, and SOD activity according to pyrogallol autoxidation method at 420 nm. The study was approved by the Ethic Committee of the Hospital de Clínicas, UBA. Results: In both groups there were no differences in age, body mass index, glucose or lipoprotein profile. In EAT from CAD patients, SOD activity was decreased compared to No CAD (p=0.024) without differences in CAT activity. SOD and CAT activities were not associated with lipoprotein profile, however both enzymes showed a negative correlation with TG/HDL-chol as IR marker (p=0.01). Moreover, in EAT, CAT activity was decreased in patients with TG/HDL-chol ≥3 (p=0.038). In both groups, no differences in SOD and CAT activity was found between EAT and SAT. Conclusions: this is the first time that CAT and SOD activities are reported in EAT. Our findings suggest a possible regulation of these enzymes by IR in EAT, suggesting an increase in oxidative stress in this tissue; future studies are necessary to explain the regulation of both enzymes.