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 degrees 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.