Endothelial progenitor cell (EPC)

Endothelial progenitor cells are a heterogeneous group of stem/progenitor cells capable of differentiating into mature endothelial cells. They play a critical role in the regeneration and repair of blood vessel linings through processes such as vasculogenesis and angiogenesis. First described in the late twentieth century, these cells are found primarily in bone marrow but also circulate at low levels in peripheral blood. There is ongoing debate about their precise definition due to overlapping markers with hematopoietic stem cells and monocytes; however, they are generally characterized by expression patterns including CD34, VEGFR2, and sometimes CD133 for early-stage populations. EPCs have been implicated as therapeutic targets for cardiovascular diseases—such as myocardial infarction, heart failure, stroke—as well as wound healing disorders. Their ability to home to sites of vascular injury makes them attractive candidates for regenerative medicine strategies aiming to restore damaged endothelium or promote new vessel formation. Clinical studies have explored both autologous transplantation approaches using patient-derived EPCs as well as pharmacologic interventions that boost endogenous populations. Therapeutically relevant subtypes include early outgrowth "colony forming unit-Hill" cells—which share features with monocytes—and late outgrowth "endothelial colony-forming cells" that display robust proliferative capacity akin to mature endothelium. Drugs such as glucocorticoids, TNF inhibitors, antimalarials, and prostanoids like iloprost have shown potential effects on increasing numbers or improving function of these progenitors. Despite promise for tissue engineering applications—including seeding grafts/stents—challenges remain regarding standardizing definitions/assays across studies; there is also concern about promoting pathological neovascularization under certain conditions such as cancer.

Other names

EPCendothelial colony-forming cell (ECFC)circulating angiogenic cell (CAC)colony forming unit-Hill cell (CFU-Hill)myeloid angiogenic cell (MAC)

Enhancement of EPC mobilization or function to promote vascular repair or neovascularization - For example, anti-inflammatory agents may increase endogenous EPC numbers or activity; prostanoids like iloprost can enhance mobilization and survival of ECFCs.