Bovine vascular endothelial cells plated at low cell density in the presence of high (10%) concentrations of serum and maintained on plastic tissue culture dishes proliferate slowly. If the cultures were exposed to fibroblast growth factors (FGF), the cells proliferated actively and, after a week, a monolayer composed of closely apposed and highly contact-inhibited mononucleated cells formed. In contrast to cultures maintained on plastic, cultures maintained on dishes coated with an extracellular matrix produced by corneal endothelial cells proliferated rapidly and no longer required FGF to reach confluence. Addition of FGF to such cultures did not decrease the mean doubling time, which was already at a minimum (18 h), nor did it result in a higher final cell density, which was already at a maximum (700-1,000 cells/mm2). Likewise, although human umbilical vein endothelial cells plated at low density on plastic did not proliferate, they proliferated rapidly when plated on dishes coated with an extracellular matrix. However, unlike bovine vascular endothelial cells, they still required FGF if the cultures were to become confluent.
Denis Gospodarowicz, Charles Ill