Metabolic aspects of cardiac and skeletal muscle tissues in the condition of hypoxia, ischaemia and reperfusion induced by extracorporeal circulation.

Extracorporeal circulation (ECC) during aortopulmonary bypass surgery allows the investigation of the metabolic and biochemical effects of hypoxia (skeletal muscle), ischaemia (cardiac muscle) and reperfusion (skeletal and cardiac muscle) in homogeneous groups of patients. In this study we examined the mitochondrial enzymic response to oxidative stress in 40 subjects, and analysis was carried out on heart and skeletal-muscle biopsies taken before, during and after aortic clamping and 115 min of ECC. The results obtained constitute a clinical and biochemical picture characterized by some peculiar adaptive changes of enzymic activities which thus antagonize the oxidative damage due to acute hypoxia, ischaemia and reperfusion. Consequently it seems that this cellular protective mechanism plays a crucial role in the reversibility of oxidative damage in hypoxic and ischaemic tissues.