RESUMO
OBJECTIVES: The aim of the study was to assess proliferative ability of the stem cells in the umbilical cord blood and their potential to differentiate in in vitro culture. MATERIAL AND METHODS: The material consisted of 14 samples of umbilical cord blood collected from the umbilical cord vein. Mononuclear cells were isolated using the method of density gradient medium. Next, CD34 cells were isolated from the interphase with the use of the VarioMACS sorter and anti-CD34 antibodies. Long-term cultures were conducted on Iscove's modified Dulbecco medium (IMDM) with addition of granulocyte-macrophage colony stimulating factor (GM-CSF) and nerve growth factor (NGF). Qualitative identification was performed using the May-Grunwald-Giemsy staining method, taking photographs with a confocal microscope, and with the immunoenzymatic method. RESULTS: In our research, CD34+ stem cells constituted 1.16% of the mononuclear cells, and after centrifugation in medium 0.37% of leukocytes in whole umbilical cord blood. Even after 60 days of culture without addition of the growth factors, CD34+ cells were present in the fraction of adherent cells. After stimulation with GM-CSF and NGF a part of the umbilical cord blood cells were transformed into nerve cells (presence of neuron-specific enolase was shown) and into cells morphologically similar to fibroblast and dendritic cells. CONCLUSIONS: After stimulation with GM-CSF and NGF cytokines, the umbilical cord blood cells proliferate in long-term medium, transform into nerve cells and into cells similar to fibroblast and dendritic cells.