Procoagulant and Prothrombotic Responses of Human Endothelium to Indomethacin and Endotoxin in Vitro Relevance to Non-Steroidal Anti-Inflammatory Drug Enteropathy

Abstract

Background: In view of the association between non-steroidal anti-inflammatory drugs (NSAIDs) and microvascular injury in the intestine, this study investigated the procoagulant changes in cultured human umbilical vein endothelial cells (HUVEC) when exposed to indomethacin either alone or in the presence of bacterial lipopolysaccharide (LPS). Methods: Confluent HUVEC cultures were cultured for 1, 6, 12, and 24 h in the presence of LPS (10 μg/ml) with or without indomethacin (1-100 μM). After incubation, supernatants were analysed for 6-keto-prostaglandin (PG) F_1α and PGE₂ content, whereas cells were freeze-fractured and assayed in a one-stage clotting assay for the expression of procoagulant activity (PCA). Results: LPS induced a significant expression of PCA at 6, 12, and 24 h, with a significantly increased production of 6-keto-PGF_1α, whereas the increased PGE₂ production was much less pronounced. Indomethacin alone induced a time-dependent PCA response; when coincubated with LPS the PCA response was greater than that produced by either indomethacin or LPS alone. Indomethacin totally abolished the synthesis of antithrombotic eicosanoids. Conclusion: Indomethacin induces PCA in HUVEC and augments LPS-induced PCA, while it abolishes the antithrombotic prostanoid response in these cells. These observations may be relevant to the microvascular injury and thrombosis observed in NSAID enteropathy.

Key Words:

• Haemostasis
• inflammation
• lipopolysaccharide
• procoagulant activity
• prostacyclin
• prostaglandin E₂
• tissue factor