IL-1-induced procoagulant and fibrinolytic activities of human endothelium grown on carbodiimide crosslinked proteins.

We examined the regulation of procoagulant activity and the production of fibrinolytic components by human vascular endothelium grown on coating membranes of gelatin, pure or mixed with albumin, crosslinked by carbodiimide ((G)C, (AG)C) in comparison with plastic culture dishes. Confluent monolayers were stimulated by human recombinant interleukin (IL-1 beta) and responses in terms of tissue factors like procoagulant activity, tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI-1) were followed for up to 72 h. Procoagulant activity of cell extracts displayed similar patterns whatever the substratum tested. Quantitative immunological assays revealed a 2-fold increase in tPA antigen released from monolayers grown on (G)C and on (AG)C compared to cells grown on plastic. Exposure of monolayers to IL-1 beta reduced the secretion of tPA antigen which still reached higher values on coated than on uncoated substratum. We found that the quasi-totality of tPA formed stable complexes with PAI-1, thereby suppressing measurable fibrinolytic activity. IL-1 beta stimulated the release of PAI-1 antigen quantified by immunoassay and the kinetics of secretion were comparable on both coated and uncoated substratum.