Early outgrowth cells versus endothelial colony forming cells functions in XXXX .

@entity1 @entity455 @entity1423 @entity4770 @entity842 @entity9859 @entity715 @entity2247 @entity65
BACKGROUND: Endothelial progenitor cells (EPCs) have been implicated in neoangiogenesis, endothelial repair and cell-based therapies for @entity65 . We have previously shown that the recruitment of EPCs to sites of @entity455 is facilitated by platelets where EPCs, in turn, modulate platelet function and @entity715 . However, EPCs encompass a heterogeneous population of progenitor cells that may exert different effects on platelet function. Recent evidence suggests the existence of two EPC subtypes: early outgrowth cells (EOCs) and endothelial colony-forming cells (ECFCs). We aimed at characterizing these two EPC subtypes and at identifying their role in @entity1423 . METHODS: EOCs and ECFCs were generated from @entity1 peripheral blood mononuclear cells (PBMCs) seeded in conditioned media on fibronectin and collagen, respectively. The morphological, phenotypical and functional characteristics of EOCs and ECFCs were assessed by optical and confocal laser scanning microscopes, cell surface markers expression, and Matrigel tube formation. The impact of EOCs and ECFCs on @entity1423 was monitored in collagen-induced optical aggregometry and compared with PBMCs and @entity1 umbilical vein endothelial cells (HUVECs). The levels of the anti-platelet agents' @entity842 (NO) and @entity4770 ( @entity4770 ) released from cultured cells as well as the expression of their respective producing enzymes NO synthases (NOS) and cyclooxygenases (COX) were also assessed. RESULTS: We showed that EOCs display a monocytic-like phenotype whereas ECFCs have an endothelial-like phenotype. We demonstrated that both EOCs and ECFCs and their supernatants inhibited @entity1423 ; however ECFCs were more efficient than EOCs. This could be related to the release of significantly higher amounts of NO and @entity4770 from ECFCs, in comparison to EOCs. Indeed, ECFCs, like HUVECs, constitutively express the endothelial (eNOS)-and inducible (iNOS)-NOS isoforms, and @entity9859 and weakly express @entity2247 , whereas EOCs do not constitutively express these NO and @entity4770 producing enzymes. CONCLUSION: The different morphological, phenotypic and more importantly the release of the anti-aggregating agents @entity4770 and NO in each EPC subtype are implicated in their respective roles in platelet function and thus, may be linked to the increased efficiency of ECFCs in inhibiting @entity1423 as compared to EOCs.
