Changes in the fibrinolytic components of cultured human umbilical vein endothelial cells induced by endotoxin, tumor necrosis factor-alpha and interleukin-1alpha.
OBJECTIVE
Vascular fibrinolysis, a major natural defense mechanism against thrombosis, is a highly regulated process. The aim of this study was to evaluate the effect of endotoxin, tumor necrosis factor-alpha (TNFalpha) and interleukin-1alpha (IL-1alpha), on the fibrinolytic potential of cultured human umbilical vein endothelial cells (HUVEC).


METHODS
Samples of stimulated conditioned media were collected over a period of 24 hours to determine: plasminogen activator (PA) and plasminogen activator inhibitor (PAI) activity, PAI-1 mRNA, tissue-type plasminogen activator (t-PA) antigen and urokinase-type plasminogen activator (u-PA) antigen.


RESULTS
Similar changes were observed after endotoxin and cytokine stimulation: there was a significant increase of PAI activity (p<0.01), starting at 6 hours, which remained 24 hours after stimulation. PAI-1 mRNA also showed an important rise with these agents, although cytokines induced an earlier and more intense inhibitor response (up to 6-fold increase). PA activity increased significantly at 6 hours (p<0.01) to drop at 24 hours and was mainly related to the presence of u-PA.


CONCLUSIONS
We conclude that endotoxin,+TNFalpha and IL-1alpha induce profound alterations in the fibrinolytic potential of HUVEC, characterized by an initial rise of activators (u-PA) followed by a strong increase of PAI-1. These changes may be of pathophysiologic significance for thrombosis and inflammatory reactions.
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Laboratory of Vascular Biology and Thrombosis, Hematology Service, School of Medicine, University of Navarra, Pamplona, Spain.
Chordá
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D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000032:analysis; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D004731:Endotoxins / Q000494:pharmacology*; D005342:Fibrinolysis / Q000187:drug effects*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis; D010960:Plasminogen Activators / Q000032:analysis; D010959:Tissue Plasminogen Activator / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis
D017077:Culture Media, Conditioned; D004731:Endotoxins; D007375:Interleukin-1; D017395:Plasminogen Activator Inhibitor 1; D014409:Tumor Necrosis Factor-alpha; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator