title: Evidence that heparin but not hirudin reduces PAI-1 expression in cultured human endothelial cells.
abstract: Heparin and other antithrombotic drugs besides their anticoagulant action could have a profibrinolytic effect. We have analyzed the effect of unfractionated heparin (UFH) and hirudin on PAI-1 gene expression in human umbilical vein endothelial cells (HUVEC). Cells were stimulated with UFH (1 and 10 IU/ml) and hirudin (20 and 100 TIU/ml). Samples were obtained before and 2, 6, and 24 hours after stimulation. mRNA analysis was conducted by reverse transcription followed by polymerase chain reaction, and PAI-1 antigen was determined by ELISA. Addition of UFH (10 IU/ml) to HUVEC resulted in a decrease of PAI-1 mRNA at 6 hours (40% reduction) and 24 hours (60% reduction) and PAI-1 antigen. Hirudin, however, did not modify significantly the PAI-1 mRNA nor the inhibitor secretion. The addition of UFH (10 or 100 IU/ml) to endotoxin-stimulated HUVEC also reduced the increased PAI-1 mRNA and antigen secretion (45%), whereas no effect could be observed with hirudin. Our results suggest that UFH, but not hirudin, by reducing the endothelial expression of PAI-1 might have a profibrinolytic effect.
mesh_terms: D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism*; D004731:Endotoxins / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology; D005343:Fibrinolytic Agents / Q000494:pharmacology; D005784:Gene Amplification; D015870:Gene Expression / Q000187:drug effects; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000235:genetics; D006493:Heparin / Q000494:pharmacology*; D006629:Hirudins / Q000494:pharmacology*; D006801:Humans; D007231:Infant, Newborn; D017395:Plasminogen Activator Inhibitor 1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014471:Umbilical Veins