Endothelial progenitor cells from embryonic stem cells

Stem cell research has gained significant interest due to their potential to repopulate damaged or diseased cell tissues. Pluripotent embryonic stem (ES) cells, able to rapidly and stably proliferate in vitro, provide an excellent system for studying cellular differentiation events. Our lab is particularly interested in stem cell differentiation of the endothelial lineage. Recent evidence has demonstrated that induction of Flk-1 positive expressing cells can be achieved by culturing ES cells on type IV collagen-coated dishes. Vascular endothelial growth factor (VEGF), a cytokine for the Flk-1 receptor, can stimulate endothelial cells to mimic vasculogenesis through cell migration and the formation of line, or tube-like structures in vitro. ES cells were; induced to differentiate on collagen type IV coated-dishes. Flk-l+ cells were then sorted and replated on collagen type IV and treated with VEGF. Spontaneous tube-like formations were observed in the unsorted endothelial progenitor cells without VEGF exposure. Two distinct cell morphologies arose from the Flkl+ sorted cells: a cobblestone morphology and smooth muscle-like cells that stained positive for α-smooth muscle actin. Current efforts are being made to further characterize the maturing cell types arising from Flk-1+ cell populations and develop methodology to isolate a pure population of endothelial cells.