 Finally, both ECs and adipocytes have been suggested to influence HSC activity in the bone marrow.Studies using antibody-mediated disruption of the VEGF receptors on ECs correlated with poor engraftment of donor cells.HUVECs, or endothelial cells isolated from umbilical veins, that were programmed via viral gene manipulation to signal through the Notch and Angiopoietin pathways were found to support and maintain LT-HSCs.