CXCR4 and acute myocardial infarction: Numerous studies have found that SDF-1α not only stimulated haematopoietic stem cell engraftment but also recruited progenitor cells to the ischaemic region by interacting with CXCR4.16 After heart surgery or acute myocardial infarction, the expression of SDF-1α in the peri-injury zone was up-regulated, with profoundly increased numbers of stem/progenitor cells in the injured region.17,18