Human embryonic stem cells for vascular development and repair.

Embryonic stem cells, derived from the inner cell mass of embryos in the blastocyst stage, are cells capable of perpetual self-renewal and long-term propagation and hold the potential to differentiate to progeny of the three embryonic germ layers. Since their derivation approximately two decades ago, exploration of mouse ES cells made major advances in ES cell differentiation research and in the successful development and propagation of various cell types. The subsequent derivation of ES cells from human embryos allows detailed study of early developmental events practically unreachable in early human embryos, and the potential derivation of a variety of adult cell types differentiated from the ES cells holds immense therapeutic promise. Recently, the study of ES cell-derived teratomas identified the partial presence of human ES cell-derived premature vessels within the teratoma, and a preliminary protocol for the in vitro derivation of a vascular progenitor was developed based on the study with the mouse ES cells. Furthermore, genetic profiling identified a pattern of expression of various endothelial and vascular smooth muscle cell genes that provide additional information on the degree of vascular development that ES cells undergo. Finally, the clinical application of ES cells in transplantation medicine is closer than ever following the affirmation that human ES cell-derived endothelial progenitors conferred increased neovascularization in transplanted engineered skeletal muscle. This review summarizes these recent advances in vascular development from human ES cells and their potential clinical applications.