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BACKGROUND: Changes of both stem cell markers and endothelial cell phenotype help understand characteristics of endothelial progenitor cells during adherent differentiation. However, there is still no specific cell marker to distinguish from mature endothelial cells.
OBJECTIVE: To study the changes of stem cell markers and endothelial cell phenotype during the differentiation of rat peripheral blood mononuclear cells into endothelial cells.
DESIGN, TIME AND SETTING: Cell observation study was performed in the Laboratory of Cardiac Surgery, Qingdao Municipal Hospital between June 2004 and December 2008.
MATERIALS: Peripheral blood was drawn from male SD rats to obtain mononuclear cells by Ficoll density gradient centrifugation.
METHODS: Mononuclear cells were in vitro cultured in fibronectin culture medium and induced by vascular endothelial growth factors (VEGF) and basic fibroblast growth factors (bFGF) in order to stimulate a differentiation into endothelial cells.
MAIN OUTCOME MEASURES: Adherent cells in the culture system were identified for CD31, CD34, Flk-1 and vWF with immunochemistry within 1-7 days.
RESULTS: The expressions of CD31, CD34, Flk-1, vWF on adherent cells were different in different time durations. The expressions of CD31 and CD34 started on the 2nd day of culture, reached the peak on the 4th day, gradually decreased and even disappeared on the 6th day. While, Flk-1 expressed on the 3rd day of culture, gradually increased, and reached at the peak on the 7th day. vWF expressed gradually until 100% on the 7th day.
CONCLUSION: The differentiation of peripheral blood stem cells into endothelial progenitor cells is characterized by the appearance of endothelial cell phenotypes and the disappearance of stem cell markers, both in the manner of gradual progression. |