Cardioprotection by ε-Protein Kinase C Activation From Ischemia

Background— We previously showed that a selective activator peptide of e-protein kinase C (PKC), ψeRACK, conferred cardioprotection against ischemia-reperfusion when delivered ex vivo before the ischemic event. Here, we tested whether in vivo continuous systemic delivery of ψeRACK confers sustained cardioprotection against ischemia-reperfusion in isolated mouse hearts and whether ψeRACK treatment reduces infarct size or lethal arrhythmias in porcine hearts in vivo. Methods and Results— After ψeRACK was systemically administered in mice either acutely or continuously, hearts were subjected to ischemia-reperfusion in an isolated perfused model. Whereas ψeRACK-induced cardioprotection lasted 1 hour after a single intraperitoneal injection, continuous treatment with ψeRACK induced a sustained preconditioned state during the 10 days of delivery. There was no desensitization to the therapeutic effect, no downregulation of ePKC, and no adverse effects after sustained ψeRACK delivery. Porcine hearts were subjecte...