Inhibition of Apoptosis Signal–Regulating Kinase 1 Reduces Myocardial Ischemia–Reperfusion Injury in the Mouse

BACKGROUND Despite the clear advantages of reperfusion in acute myocardial infarction, part of the myocardium is injured during reperfusion by reactive oxygen species. Reactive oxygen species activate apoptosis signal-regulating kinase-1, a key mediator in cell death. We hypothesized that inhibition of apoptosis signal-regulating kinase-1 at the time of reperfusion would protect the heart from ischemia-reperfusion injury. METHODS AND RESULTS Male CD1 mice underwent transient coronary artery ligation (30 minutes) followed by reperfusion or underwent sham surgery (n=10 to 12 per group). A selective small-molecule inhibitor of apoptosis signal-regulating kinase-1 (GS-459679) was given immediately after reperfusion (10 or 30 mg/kg IP). Infarct size was measured early (at 24 hours, in a subgroup of mice) by triphenyl tetrazolium chloride staining and late (at 7 days) by Masson's trichrome staining for fibrosis. Apoptosis was assessed by measurement of caspase-3 activity and by determination of DNA fragmentation in cardiomyocytes bordering the infarct. Transthoracic echocardiography was performed before surgery and then at 24 hours and 7 days later. Treatment with GS-459679 at reperfusion led to a significant dose-related reduction in infarct size (31% for 10 mg/kg [P<0.001 versus vehicle] and 60% for 30 mg/kg [P<0.001 versus vehicle]), inhibition of apoptotic cell death, and preservation of left ventricular dimension and systolic function at both 24 hours and 7 days. CONCLUSIONS Inhibition of apoptosis signal-regulating kinase-1 at the time of reperfusion limits infarct size and preserves left ventricular function in a model of acute myocardial infarction in the mouse.