Reperfusion and calculated RISKs: pharmacological postconditioning of human myocardium.

The last five years have witnessed a remarkable resurgence of interest in myocardial reperfusion injury. Reperfusion is absolutely essential to salvage ischaemic myocardium but experimental and clinical studies show that reperfusion-associated injury may mask the full benefits of prompt reperfusion in acute myocardial infarction. In the current issue of the British Journal of Pharmacology, Mudalagiri et al demonstrate a protective effect against simulated reperfusion injury using exogenously applied erythropoietin in human isolated myocardium. Crucially, the benefits of erythropoietin were observed when it was administered specifically during re-oxygenation. The demonstration that the protective effects of the cytokine were dependent on PI3-kinase/Akt and ERK1/2 activation provides compelling evidence that reperfusion injury salvage kinases (RISKs) are key survival mechanisms in human myocardium, as they are in experimental animal species. Although erythropoietin may be only one of several potential pharmacological approaches in human patients, this study establishes the important proof-of-principle that activation of RISKs is protective in human myocardium and could be a promising therapeutic target in acute myocardial infarction.