Locally Transplanted CD34+ Bone Marrow–Derived Cells Contribute to Vascular Healing After Vascular Injury

Abstract Introduction Vascular progenitor cells contribute to repair of injured vasculature. In this study, we aimed to investigate the role of bone marrow–derived cells in the intimal formation after arterial injury. Methods and Results Balloon injury of the femoral artery of wild-type mice was followed by local delivery of bone marrow–derived cells from GFP transgenic mice. The arteries were collected 1, 4, 7, and 14 days after injury and studied for morphology, localization, and phenotypes of delivered cells. Bone marrow–derived cells were present in the intima only at the early stages of arterial injury and expressed endothelial progenitor cell markers (CD31, CD34, and VEGFR-2). In the areas where intima was thicker, bone marrow–derived cells differentiated to intimal smooth muscle cells but they did not fuse with intimal cells. Delivery of CD34+ cells contributed to a 1.5-fold inhibition of intimal hyperplasia. Conclusion Bone marrow–derived endothelial cells differentiated but did not fuse with vascular smooth muscle cells at the early stages of intimal formation and contributed to intimal hyperplasia.