Augmentation of interleukin-1 induced prostacyclin production by endothelial cell growth factor: implications for...

Interleukin-1 (IL-1) is a key inflammatory cytokine that has important effects both on endothelial cell (EC) growth and synthetic function. Fibroblast growth factors (FGF's), including endothelial cell growth factor (ECGF), are important regulators of EC growth, and their role in the pannus formation and synovial proliferation seen in chronic arthritis has been emphasized recently. While ECGF mediated EC proliferation is inhibited by IL-1, potential interaction of these peptides on other aspects of EC function has not been described. As both IL-1 and FGF may be important disease mediators in rheumatoid arthritis, we studied their combined effects on EC prostacyclin production. While ECGF alone had no measurable effects, it enhanced rIL-1 alpha induced prostacyclin production in a dose and time dependent fashion. Both pertussis and cholera toxins blocked the augmentation, suggesting a role for G proteins in mediating the synergism. These studies demonstrate that ECGF can alter certain effects of IL-1 on the endothelium, and point to an additional role that this family of growth factors may play in some inflammatory disorders.