Abstract:

BACKGROUND: Endothelial progenitor cells (EPCs) not only participate in embryonic angiogenesis, but also participate in postnatal angiogenesis and vascular intima damage repair, exhibiting a great significance for the treatment of ischemic diseases. Nevertheless, the isolation, culture and identification of endothelial progenitor cells remain controversial.
OBJECTIVE: To isolate and culture endothelial progenitor cells from peripheral blood and bone marrow in vitro, and to compare their biological characteristics.
METHODS: SD rat bone marrow and peripheral blood mononuclear cells were isolated by density gradient centrifugation, inoculated on fibrinin-coated culture flask and cultured with complete medium containing vascular endothelial growth factor, basic fibroblast growth, and epidermal growth factor. Cell morphplogy, immunocytochemical staining, flow cytometry and transmission electron microscopy as well as Dil-acLDL, FITC-UEA-1 double fluorescence staining were performed on the harvested adherent cells.
RESULTS AND CONCLUSION: A large number of endothelial progenitor cells were harvested from bone marrow, and they were grown in a colony-like manner and show strong proliferative capacity. A small number of endothelial progenitor cells were harvested from peripheral blood. They were grown in a sparse manner and could adhere to flask wall but could not be passaged. Immunocytochemical staining showed that adherent cells from two sources were positive for CD133, CD34, Flk-1 and VII factors at different time periods. Laser confocal microscopy showed that adherent cells from two sources can stain Dil-acLDL and FITC-UEA-1. Transmission electron microscopy showed that W-P body was found in the peripheral blood endothelial progenitor cells. These results indicate that endothelial progenitor cells can be cultured from both bone marrow and peripheral blood, but early-stage endothelial progenitor cells can be cultured from bone marrow and late-stage endothelial progenitor cells can be cultured from peripheral blood. These two kinds of cells show different biological characteristics.

Key words: stem cells, stem cell culture and differentiation, endothelial progenitor cells, bone marrow, peripheral blood, isolation, identification, immunocytochemical staining, early endothelial progenitor cell, late-stage endothelial progenitor cells, biological characteristics, rats, stem cell photographs-containing paper