Abstract 614: 1,25-dihydroxyvitamin D Enhances Vegf-stimulated Porcine Adipose-derived Mesenchymal Stem Cells Toward the Endothelial Phenotype Involving Wnt/β-catenin Pathway

Abstract

Background: Cell-based therapy using adipose-derived mesenchymal stem cells (AMSCs) is an attractive option for re-endothelialization post-angioplasty procedures. Vitamin D levels in circulating blood may regulate AMSC-based re-endothelialization of injured arteries. To our knowledge, the role of vitamin D and vascular endothelial growth factor (VEGF) in the differentiation of adipose-derived AMSCs into endothelial cells (ECs) has not been examined. In this study, we investigated the effect of vitamin D on VEGF-induced differentiation of MSCs into ECs. Methods and Results: MSCs isolated from porcine adipose tissue were CD11b-CD34-CD44+CD73+CD90+ and showed characteristics of MSCs. The MSCs were stimulated and differentiated into ECs with endothelial growth media (EGM+50ng/ml of VEGF) and EGM media containing 10nM of calcitriol (EGM+50ng/ml of VEGF +10nM calcitriol) for 10 days. The EC differentiation was assessed by mRNA expression by qPCR and protein expression by flow cytometry for endothelial cell markers. Calcitriol enhanced EGM+VEGF-induced differentiation of MSCs into ECs, as revealed by 2-fold increase in mRNA and 4-fold increase in protein expression of EC markers. Angiogenesis assay and acetylated low density lipoprotein (LDL) uptake assay were used to assess the endothelial functionality that showed significant increase in capillary tube sprouting, and an increase in LDL uptake by the differentiated cells in response to EGM +VEGF+ calcitriol. Examination of the findings from Wnt Pathway array revealed a 3-fold decrease in β-catenin and 3-fold increase in KREMEN1 protein in the cells treated with EGM + VEGF+calcitriol. Conclusion: Vitamin D significantly enhanced VEGF-induced differentiation of MSCs into endothelial cells. Thus, vitamin D status of the patients undergoing coronary intervention might regulate the development of thrombosis and intimal hyperplasia.