Ischemia affects cardiac proteins in healthy animals less severely than in human patients

Recently, our group showed that in human hearts proteins are extremely sensitive to ischemic injury. The purpose of this investigation was to evaluate the effects of ischemia on contractile and cytoskeletal proteins in rabbit and pig hearts and to compare these findings with those obtained in humans. Rabbit hearts were arrested by perfusion with Euro-Collins solution at different temperatures. Hearts perfused with buffer served as controls. Tissue samples were incubated for varying time intervals and processed for immunohistochemistry and electron microscopy. Porcine hearts were treated in the same manner. Changes in the localization of myosin, desmin, and tropomyosin antibodies were evaluated and the degree of ischemic injury was determined by electron microscopy. Healthy animal hearts tolerate ischemia better than human hearts. Cardiac proteins are more sensitive to ischemia than the ultrastructural cellular organelles. Temperatures as low as 0°C produce more cell damage than 4°C and should therefore be avoided. The Euro-Collins solution protects the myocardium better than buffer. We conclude that healthy animal hearts are more resistant to ischemia than diseased human hearts and that results from experimental studies should be interpreted with caution with regard to the human situation.