Development of endothelial cell lines from embryonic stem cells - A tool for studying genetically manipulated endothelial cells in vitro

Totipolent embryonic stem cells can be induced to differentiate to endothel ium in vitro. This may be a useful tool for obtaining cultures of genetical ly manipulated endothelial cells because embryonic stem cells are relativel y easy to transfect and are commonly used for gene inactivation experiments in mice, However, embryonic stem cell-derived endothelial cells could not be easily separated from embryoid bodies and maintained in culture. In this study, we describe the isolation acid characterization of immortalized end othelial cell lines obtained from embryonic stem cells differentiated in vi tro. The cell lines were analyzed for expression of endothelial cell marker s, including growth factor receptors and adhesion molecules, and compared w ith endothelial cells obtained from the yolk sac, the embryo proper, or the heart microcirculation of the adult. We propose that this approach may be useful for obtaining endothelial cells carrying gene mutations that are let hal at very early stages of development.