Objective: To investigate the effects of endothelial cells on the proliferations of granulocytic, erythrocytic and megakaryocytic progenitor cells.
Methods: Human umbilical vein endothelial cells were collected within 12 hours after cesarean section and were cultured according to Jaffe's method. The human endothelial culture supernatant (HECS) harvested from primary culture medium was centrifuged. Bone marrow mononuclear cells of mice were prepared and then cultured in semi-solid agar or methylcellulose with the addition of HECS.
Results: Colony-forming yields were increased in the culture systems with HECS. But in the systems with no HECS, exogenous GM-CSF, EPO and IL-3 added to the hematopoietic progenitor cultures were necessary to induce colony-forming. Synergistic increase in progenitor cell expansion was observed when both HECS and exogenous cytokines were added to hematopoietic progenitor cultures.
Conclusion: 1. Endothelial cells can support the proliferation and differentiation of hematopoietic stem and progenitor cells. 2. HECS as a source of standard hematopoietic growth factors can be used in the expansion of stem cells in vitro and in the therapy of hemopathy. 3. Interactions between endothelial cells and hematopoietic stem cell or progenitors may play an important role in the regulation of hematopoiesis in vivo. 4. Endothelial cells may produce other soluble growth factors potentiating the action of a set of cytokines such as GM-CSF and IL-6.