Sca-1 + Progenitors Derived From Embryonic Stem Cells Differentiate Into Endothelial Cells Capable of Vascular Repair After Arterial Injury

Background— Embryonic stem cells possess the ability to differentiate into endothelium. The ability to produce large volumes of endothelium from embryonic stem cells could provide a potential therapeutic modality for vascular injury. We describe an approach that selects endothelial cells using magnetic beads that may be used therapeutically to treat arterial injury. Methods and Results— Large numbers of endothelial cells (ECs) with high purity were produced using Sca-1 + cells isolated with magnetic beads from predifferentiated embryonic stem cells (ESCs) cultured in α-MEM containing 10 ng/mL VEGF 165 for a minimum of 21 days (esEC). The transcription regulator histone deacetylase (HDAC3) was essential for VEGF-induced EC differentiation. Immunofluorescence or fluorescence-activated cell sorter (FACS) analysis revealed that esECs expressed a full range of EC lineage-specific markers including CD31, CD106, CD144, Flk-1, Flt-1, and von Willebrand factor (vWF). FACS analysis confirmed that 99% of esECs were CD31-positive and 75% vWF-positive. Furthermore, almost all cells were positive for DiI-acLDL uptake. When matrigel containing esECs was subcutaneously implanted into mice, various vessel-like structures were observed indicating their endothelial cell like phenotype. In keeping with this, when esECs infected with adenovirus-LacZ were injected into denuded femoral arteries of mice, they were found to form a neo-endothelium that covered the injured areas (86%±13.6%), which resulted in a 73% decrease in neointimal area 2 weeks after injury. Conclusions— We conclude that Sca-1 + cells can differentiate into functional ECs via activation of HDAC3, accelerating re-endothelialization of injured arteries and reducing neointima formation.