Experimental Studies On Endothelial Cell Differentiation From Umbilical Cord Blood Hematopoietic Stem Cells In Vitro

[Obsjective] Endothelial cell is the foundation of the neovascularization.It has become a new treatment strategy for the ischemic disease. The presentstudy aimed at setting up a culture system in vitro and looking for the effectivefactors for endothelial cells differentiation from human umbilical cord bloodcells (HUCBCs), to conform the presence of endothelial cell precursors inumbilical cord blood. [Methods] Fresh human umbilical cord blood cells were cultured in vitro anddivided into four groups: ① control group, cultured without cytokine; ② PHAgroup, cultured with PHA M form; ③ bFGF+IGF-I group, cultured withbFGF+IGF-I; ④ VEGF group, cultured with VEGF+bFGF+IGF-I. Cultured cells were observed by inverted-microscope on 0,5,7,14 days, vWF wasdetected by flow-cytometry and Weibel-Palade body was detected by electron-microscope on 8,14 days.[Results] 14 days after HUCBCs were cultured with VEGF+ bFGF+IGF-I, alarge number of caudated adherent cells were observed. Flow cytometric analysisshowed endothelial marker vWF expressed in the about 80% of the cultured cellsand the endothelial –specific Weibel-Palade body was detected in the cytoplasmby electron-microscope. In the bFGF+IGF-I group, cells growed slowly and weredeath of the seventh day. 24 hour after HUCBCs were cultured with PHA M form,we found that mononuclear cells aggregated, 8 days later, a number of caudatedadherent cells were observed and flow cytometric analysis showed endothelialmarker vWF expressed in the about 60% of culture cells, also the endothelial–specific Weibel-Palade body was detected in the cytoplasm by electron-microscope. In the control group, cells growed slowly and were death of the fifth day.[Conclusion] ① Endothelial cell precursors circulate in human umbilical cordblood. Human umbilical cord blood mononuclear cells can be differentiated intoendothelial cells by VEGF+bFGF+IGF-I/PHA. ② VEGF is a critical factor forendothelial cell differentiation and bFGF + IGF-I can promote synergistic effectswith VEGF. However, both bFGF and IGF-I cannot do. ③ Endothelial cells alsocan be induced with PHA from human umbilical cord blood mononuclear cells inshort-term culture, but the number of vWF+ cells are less than that in VEGFgroup. ④ Human umbilical cord blood cells may be an ideal source of stem cellsfor the treatment of the ischemic disease.