Endothelial progenitor cells and vascular repair

PURPOSE OF REVIEW: This review identifies recent advances in the field of vascular repair by regenerative endothelial cells and endothelial progenitor cells (EPCs). RECENT FINDINGS: A growing number of studies indicate that bone marrow-derived circulating EPCs do not engraft into blood vessels, but that such circulating cells may regulate vascular repair via paracrine mechanisms. Novel modes of paracrine regulation are being uncovered, such as the release of endothelial cell-derived microparticles or microvesicles that contain microRNAs which can promote vascular repair. Instead of circulating cells, tissue-resident endothelial cells or EPCs may primarily drive the restoration of vascular function after endothelial injury. In addition to the generation of endothelial cells/EPCs from pluripotent stem cells, direct reprogramming of fibroblasts to endothelial cells/EPCs is becoming an important source of regenerative vascular cells. SUMMARY: Ongoing efforts to understand the mechanisms that regulate vascular repair by resident regenerative vascular cells as well as their generation from fibroblasts and pluripotent stem cells will form the basis of future regenerative therapies.