title: Blood-forming potential of vascular endothelium in the human embryo.
abstract: Hematopoietic cells arise first in the third week of human ontogeny inside yolk sac developing blood vessels, then, one week later and independently, from the wall of the embryonic aorta and vitelline artery. To address the suggested derivation of emerging hematopoietic stem cells from the vessel endothelium, endothelial cells have been sorted by flow cytometry from the yolk sac and aorta and cultured in the presence of stromal cells that support human multilineage hematopoiesis. Embryonic endothelial cells were most accurately selected on CD34 or CD31 surface expression and absence of CD45, which guaranteed the absence of contaminating hematopoietic cells. Yet, rigorously selected endothelial cells yielded a progeny of myelo-lymphoid cells in culture. The frequency of hemogenic endothelial cells in the yolk sac and aorta reflected the actual blood-forming activity of these tissues, as a function of developmental age. Even less expected, a subset of endothelial cells sorted similarly from the embryonic liver and fetal bone marrow also exhibited blood-forming potential. These results suggest that a part at least of emerging hematopoietic cells in the human embryo and fetus originate in vascular walls.
authors.affiliation: INSERM Unité 506, Villejuif, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Oberlin
authors.forename: Manuela
authors.initials: M
authors.lastname: Tavian
authors.forename: Istvàn
authors.initials: I
authors.lastname: Blazsek
authors.forename: Bruno
authors.initials: B
authors.lastname: Péault
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D001853:Bone Marrow / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D004622:Embryo, Mammalian / Q000098:blood supply* / Q000502:physiology; D004730:Endothelium, Vascular / Q000196:embryology / Q000502:physiology*; D005434:Flow Cytometry; D006410:Hematopoiesis / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008099:Liver / Q000502:physiology; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D017154:Stromal Cells; D015017:Yolk Sac / Q000502:physiology
chemical_list: D018952:Antigens, CD34; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D017493:Leukocyte Common Antigens