Effect of temperature on in vitro proliferative activity of human umbilical vein endothelial cells

Human umbilical vein endothelial cells, skin fibroblasts, and retinal pigment epithelial cells are cultivated in medium supplemented with 15 to 20% serum in our laboratory. The effects of various incubation temperatures on the proliferation of these cells was examined. Our study shows that the mitogenic response of the endothelial cells to a change of temperature differed markedly from that of the fibroblasts and epithelial cells. Cultivation of human umbilical vein endothelial at 37 degrees C required seeding densities as high as 1-2 x 10(4) cells/cm2, and yet resulted in a low growth rate and premature senescence. However, under the same culture conditions, but at 33 degrees C, the proliferative capacity of these endothelial cells was potentiated. The results were striking; at 33 degrees C the cells grew actively and the life span was extended. The number of cumulative population doublings increased fourfold compared with that for the same cells cultivated at 37 degrees C. The inoculum size could be reduced, since at 33 degrees C the endothelial cells were able to replicate at seeding densities as low as 20 cells/cm2. The cells serially subcultured at 33 degrees C retained morphological features and specific immunological markers of endothelial cells.