Platelets and stromal cell-derived factor-1 in progenitor cell recruitment.

Stromal cell-derived factor-1 (SDF-1) is a CXC chemokine that binds to its sole counterreceptor, CXCR4. It is well reported that the SDF-1/CXCR4 signaling pathway is of vital importance to human development and to various pathophysiological phenomena, including hematopoiesis, angiogenesis, atherosclerosis, cancer growth, metastasis, and human immunodeficiency virus infection. SDF-1 promotes mobilization of bone marrow-derived endothelial progenitor cells (EPCs) to the circulation in response to vascular injury. Recently, we found that platelets express and release SDF-1 into the microcirculation upon activation and we observed that platelet-derived SDF-1 is functionally involved in recruitment of EPCs to arterial thrombi in vivo. This review discusses the unique functions of this chemokine and the newly discovered impact of platelet-derived SDF-1 into the recruitment of progenitor cells to vascular injury areas, and its subsequent effects in atherosclerosis, vascular repair, and angiogenesis.