Growth factor responses of human arterial endothelial cells in vitro

Human arterial endothelial cells were cultured in vitro for up to 40 cumulative population doublings. Culture conditions similar to those required for long-term propagation of human umbilical vein endothelial cells were employed. These included fibronectin-coated culture vessels, 5 to 20% fetal bovine serum, endothelial cell growth factor, and heparin. Thoracic aorta endothelial cells were larger than iliac artery endothelial cells. Both cell types stained positively for Factor VIII antigen by immunofluorescence. A decrease in confluent density as a function of population doubling level was correlated with the appearance of large, senescent cells in the cultures. Serum growth factors to which the arterial endothelial cells responded included insulin, transferrin, epidermal growth factor, thrombin, and somatomedins. The effect of thrombin did not require the availability of the active site of the protease. The effect of the somatomedins was only seen in the presence of heparin. Neither platelet-derived growth factor nor hydrocortisone induced arterial endothelial cell proliferation. These growth factor responses were also observed on the part of human umbilical vein endothelial cells.