Objective: To investigate the effect of Angiotensin II (AngII) on the quantity proliferation, migration and adhesion of endothelial progenitor cells (EPCs).
Methods: Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation and then the cells were plated on fibronectin-coated culture dishes. After 7 days of culture, several groups of attached cells were incubated with AngII (to make a series of concentrations: 10(-3) mol/L, 10(-5) mol/L, 10(-7) mol/L, 10(-9) mol/L) or vehicle control for the respective time points (6, 12, 24 h and 48 h). In other groups of EPCs, valsartan (1 x 10(-5) mol/L) and AngII were added to the culture medium together.EPCs were characterized as adherent cells double positive for DiLDL-uptake and lectin binding by direct fluorescent staining under a laser scanning confocal microscope. EPCs were further documented by demonstrating the expression of KDR, VEGFR-2 and AC133 with flow cytometry. EPCs proliferation, migration and in vitro vasculogenesis activity were assayed with MTT assay, modified Boyden chamber assay and in vitro vasculogenesis kit, respectively. EPCs adhesion assay was performed by replating MNCs on fibronectin-coated dishes.
Results: Incubation of isolated human MNCs with AngII increased the number of EPCs, with a maximum at 10(-3) mol/L after 24 hours (P < 0.01). In addition, AngII promotes EPCs proliferative, migratory, adhesive and in vitro vasculogenetic capacity. The effect of AngII was blocked by pretreatment of valsartan.
Conclusions: It is suggested that angiotensin II may promote EPCs augmentation and enhance its functional activity through angiotensin receptor.