Hirudin stimulates prostacyclin but not endothelin-1 production in cultured human vascular endothelial cells.
To study the effect of hirudin on endothelial cell prostacyclin (PGI2) and endothelin-1 (ET-1) production, we cultured human umbilical vein endothelial cells (HUVECs), stimulated them with 0.00001-10 kU/l of hirudin for 12-24 hours, and measured by radioimmunoassays the concentrations of 6-ketoprostaglandinF1 alfa (6-keto, a metabolite of PGI2) and ET-1 in the incubation medium. In incubation medium containing 10% serum hirudin stimulated PGI2-production dose-dependently. The lowest stimulatory hirudin concentration was 0.001 kU/l, which increased the concentration of 6-keto by 10.8 +/- 4.4% (mean +/- S.E) (p < 0.01). The greatest stimulation rate (28.6 +/- 6.2%, p < 0.001) was obtained with the highest hirudin concentration (10 kU/l), when the culture medium contained 10% human serum. The PGI2-stimulating activity was exaggerated in the absence of serum, when 1 kU/l of hirudin increased PGI2-production by 59.7 +/- 6.2% (p < 0.001, n = 14). Stimulation of PGI2 appeared after 12 hour incubation. Hirudin had no effect on the conversion of exogenous arachidonic acid to 6-keto or on the production of ET-1. We thus conclude that hirudin stimulates PGI2-production through de novo protein synthesis. Stimulation of PGI2-production by hirudin may contribute to its antithrombotic activity, since PGI2 favours vasodilatation and attenuates platelet aggregation.
Turunen
P
P
Department of Clinical Chemistry, University of Helsinki, Finland.
Mikkola
T
T
Ylikorkala
O
O
Viinikka
L
L
D000925:Anticoagulants / Q000494:pharmacology*; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D011464:Epoprostenol / Q000096:biosynthesis*; D006629:Hirudins / Q000494:pharmacology*; D006801:Humans; D013268:Stimulation, Chemical
D000925:Anticoagulants; D019332:Endothelin-1; D006629:Hirudins; D011464:Epoprostenol