| [ Summary ] |
Endothelial progenitor cells (EPCs) are bone marrow-derived stem cells that have the ability to differentiate into functional endothelial cells. EPCs also circulate in the blood and appear to home in on sites of vascular or tissue injury, contributing to both reendothelialization and neovascularization. When EPC mobilization from the bone marrow and recruitment to sites of vascular injury are impaired, vascular homeostasis may be diverted toward endothelial dysfunction and susceptibility to atherogenesis. Hemodialysis patients exhibit decreased EPC numbers compared to healthy subjects, which may be related to impaired vascular repair mechanisms and susceptibility to atherogenesis in those patients. Although the mechanisms of reduced EPC counts in hemodialysis patients remain unknown, it is possible that increased inflammatory cytokines and oxidative stress may be the culprits. New therapeutic strategies, which increase circulating EPCs, may prevent atherosclerotic vascular diseases. |