Human iliac artery endothelial cells express both genes encoding the chains of platelet‐derived growth factor (PDGF) and synthesize PDGF‐like mitogen

In human umbilical vein and bovine aortic endothelial cells in culture c‐sis gene expression and secretion of platelet‐derived growth factor (PDGF) has been previously demonstrated. We now report the presence of PDGF‐1 and PDGF‐2/sis mRNA transcripts in primary cultures of human iliac artery endothelial cells (HIA‐EC). Concomitantly, these cells synthesize and secrete PDGF‐like proteins identified by direct immunoprecipitation with specific PDGF antiserum. The PDGF proteins secreted by HIA‐EC have molecular weights of 31 and 35 kd under nonreducing conditions. Upon reduction these proteins are converted to the monomeric 15‐ and 16‐kd forms. Conditioned media derived from HIA‐EC stimulated the incorporation of 3H‐thymidine by 3T3 cells and competed with 125I‐PDGF for its binding to 3T3 cell membrane receptors. The biologic activity was stable to heating at 100°C for 10 min and sensitive to reducing agents, properties similar to those of authentic PDGF. Production of PDGF‐like mitogen by the human arterial endothelial cells may play an important role in the paracrine modulation of arterial wall regeneration following vascular injury.