The effects of mannitol, albumin, and cardioplegia enhancers on 24-h rat heart preservation

During 24 h in vitro heart preservation and reperfusion, tissue damage occu rs that seriously reduces cardiac function. Prevention of free radical prod uction during preservation and reperfusion of ischemic tissue using free ra dical scavengers is of primary importance in maintaining optimal heart func tion in long-term preservation protocols. We examined whether mannitol (68 mM) and albumin (1.4 mu M) in combination with other cardioplegia enhancers decreased free radical formation and edema and increased cardiac function during 24-h cold (5 degrees C) heart preservation and warm (37 degrees C) r eperfusion in the Langendorff-isolated rat heart. The performance of mannit ol-treated hearts was significantly decreased compared with that of hearts without mannitol treatment after 24 h of preservation with regard to recove ry of diastolic pressure, contractility (+dP/dt), relaxation (-dP/dt), myoc ardial creatine kinase release, coronary flow, and lipid peroxidation. Albu min-treated hearts demonstrated higher cardiac function (contractility and coronary flow especially) than hearts not treated with albumin or hearts tr eated with mannitol, and this appears to be due to the positive effects of increased cellular metabolism and the enhancement of membrane stability.