PP.27.01

Abstract

Objective: Endothelial progenitor cells (EPC) regenerate endothelium in several cardiovascular pathologies. Nevertheless, cardiovascular risk factors such as hypertension, could impair the EPC physiology required for this reendotelization. Microparticles harboring Sonic Hedgehog (Shh) (MP+) correct endothelial dysfunction in animal models and on endothelial cells. Recently, we developed a method to obtain human EPC from peripheral blood. Our aims were to test the effect of MP+ on expression of endothelial-associated genes and to evaluate nitric oxide (NO) production and vasculogenesis in cultured human EPC. Design and method: EPC isolated from peripheral blood of five healthy donnors were exposed for 24 hours to MP+ generated from human lymphoid cell line under mitogenic conditions. The gene expression of endothelial-relevant genes (eNOS, VEGF, VCAM, ICAM and E-Selectin) was determined by quantitative RT-PCR. Protein expression and phosphorylation of eNOS were measured by Western Blot and NO production was assessed by DAF-FM diacetate probe. In vitro vasculogenesis was performed by Matrigel assay. Results: Exposure to MP+ increased EPC gene expression of eNOS, VEGF and ICAM (p < 0.001 vs. control) whereas VCAM and E-Selectin were downregulated (p < 0.05 vs. control). The regulation of NO showed that eNOS expression and phosphorylation were increased (180% and 210% of control values, respectively, p < 0.05), thus resulting in increased NO production (212% of control values, p < 0.001). The in vitro vasculogenic capacity, evaluated by the formation of tubular-like structures, was increased by 254% (p < 0.01 vs. control) in MP+ exposed EPC. Conclusions: Microparticles harboring Shh are able to switch EPC gene expression profile towards and enhancement of NO production and vasculogenic capacity. Therefore, MP+ could be considered as a new therapeutic tool for improving EPC endothelial function that can be used for treating patients suffering cardiovascular conditions.