Human fetal endothelial cells in cluture.

Human endothelial cells were isolated from the umbilical cord vein by collagenase treatment and cultured for periods up to 6 weeks. The cultured cells were identified as endothelium by cell morphology and growth pattern, the presence of Weibel-Palade bodies, and their ability to stimulate allogeneic lymphocytes (Hirschberg et al 1974). Cultured fibroblast-like cells derived from the umbilical cord were clearly different in all three respects. Approximately one third of the primary endothelial cultures showed clear evidence of proliferation during the first 3-4 days in culture as judged by cell counting. Replicating ability in a culture was correlated with cell density at the time of seeding. Autoradiography of endothelial cells after exposure to 3-H-thymidine showed a 30-fold increase in nuclear labelling from day 1 to day 3 in culture. The endothelial cells have so far been subcultured three times.