Abstract
BACKGROUND: We previously reported that a vascular endothelial stem cell population resides in pre-existing blood vessels in mice and may contribute to vascular endothelial cells in liver injury or hind limb ischemia models in the long-term. However, whether such stem cells exist in humans and can differentiate specifically into vascular endothelial cells have not been determined. We hypothesized that CD157(+) vascular endothelial cells in humans may also possess high angiogenic potential. METHODS: First, human-derived induced pluripotent stem cells were differentiated into vascular endothelial cells and the expression of CD157 was monitored during the differentiation process. We found that CD157 emerged 11 days after the induction of differentiation, peaked at 14 days, and then declined by 24 days. We also evaluated blood vessel formation by 14- and 24-day-old vascular endothelial cells. RESULTS: It was found that 14-day-old cells, when CD157 expression was at its peak, formed more blood vessels than 24-day-old cells. CONCLUSION: These results suggest that vascular endothelial cells expressing CD157 have high angiogenic potential and may exist as vascular endothelial stem cells.