Effects of aspirin on number, activity and inducible nitric oxide synthase of endothelial progenitor cells from peripheral blood.

Aim: To investigate whether aspirin has an influence on endothelial progenitor cells (EPC).

Methods: Total mononuclear cells (MNC) were isolated from peripheral blood by Ficoll density gradient centrifugation, then cells were plated on fibronectin-coated culture dishes. After 7 d of culture, attached cells were stimulated with aspirin (to achieve final concentrations of 1, 2, 5, and 10 mmol/L) for 3, 6, 12, and 24 h. EPC were characterized as adherent cells that were double positive for 1,1-dioctadecyl-3,3,3,3-tetramethylindocarbocyanine low density lipoprotein (DiLDL) uptake and lectin binding by direct fluorescent staining. EPC proliferation and migration were assayed using a 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and a modified Boyden chamber assay, respectively. An EPC adhesion assay was performed by replating the EPC on fibronectin-coated dishes, and then adherent cells were counted. In vitro vasculogenesis activity was assayed by using an in vitro vasculogenesis kit. Inducible nitric oxide synthase (iNOS) was assayed by Western blotting.

Results: Incubation of isolated human MNC with aspirin decreased the number of EPC. Aspirin also decreased the proliferative, migratory, adhesive, and in vitro vasculogenesis capacity of EPC, and also their iNOS levels in a concentration- and time-dependent manner.

Conclusion: Aspirin decreases (1) the number of EPC; (2) the proliferative, migratory, adhesive and in vitro vasculogenesis capacities of EPC; and (3) iNOS levels in EPC.