Thromboxane and prostacyclin generation by intact human vessels in response to balloon catheter trauma.

Recent description of thromboxane (TXA2) synthesis by endothelial cells in addition to prostacyclin (PGI2) has stimulated interest in the significance of TXA2 generation by vessel walls. We studied TXA2 and PGI2 release from human umbilical veins with intact and continuous endothelium. Resting TXB2 (stable metabolite of TXA2) concentrations in umbilical vein effluent (mean 0.45 +/- 0.07 ng/ml) were lower than those of 6-keto-PGF1 alpha (stable metabolite of PGI2) (mean 92 +/- 26 ng/ml). Following mechanical trauma to the umbilical veins with a balloon catheter, documented by adherence of indium111-labeled platelets, both TXA2 and PGI2 increased in the venous effluent. Increase in TXB2 (65%) was less than that in 6-keto-PGF1 alpha (199%). These data show that a) human vessel walls generate both TXA2 and PGI2, b) both TXA2 and PGI2 increase following mechanical trauma, the former less than the latter. Vessel wall TXA2 generation may become pathologically relevant in conditions of decreased PGI2 generation.