Stromal cell-derived factor-1α signals via the endothelium to protect the heart against ischaemia-reperfusion injury.

•SDF-1α protects against ischaemia-reperfusion injury, but the mechanism is unknown.•Exogenous SDF-1α is protective when delivered just prior to reperfusion.•The acute infarct-sparing effect appears to be mediated by endothelial cells.•Cardiomyocyte-specific deletion of CXCR4 was found to be cardioprotective per se.