ALTERATION OF ENDOGENOUS ANTIOXIDANT ENZYMES IN NATURALLY-OCCURRING HYPERTROPHIC CARDIOMYOPATHY

We have recently developed a porcine model with naturally occurring hy pertrophic cardiomyopathy (HCM). Similar to humans, occluded intramura l coronary artery and damaged mitochondria are frequently observed in these animals in which the disease is thought to be associated with th e local ischemia of myocardium. In view of antioxidant functions invol ved in the ischemic injury, we measured the expression of endogenous a ntioxidant enzymes in the tissues with and without HCM. The results sh owed a significant increase of Cu,Zn-superoxide dismutase (SOD), but n ot Mn-SOD, and decrease of catalase (CAT) activities in the various ar eas of HCM hearts. It was demonstrated that SOD/CAT ratios in the HCM hearts were significantly higher than those in normals and were found to be dramatically correlated with the severity of cardiac hypertrophy . The altered SOD/CAT ratio was also consistent with increase in lipid damage. We hypothesize that the elevated SOD combined with an inadequ ate amount of H2O2 scavenging enzyme may lead HCM heart at oxidative s tress risk. However, the pathogenic role of imbalanced antioxidant enz yme needs to be further explored.