Altered prostanoid production by fibroblasts cultured from the lungs of human subjects with idiopathic pulmonary fibrosis

Background: Prostanoids are known to participate in the process of fibrogenesis. Because lung fibroblasts produce prostanoids and are believed to play a central role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), we hypothesized that fibroblasts (HF) cultured from the lungs of patients with IPF (HF-IPF) have an altered balance between profibrotic (thromboxane [TX]A(2)) and antifibrotic (prostacyclin [PGI(2)]) prostaglandins (PGs) when compared with normal human lung fibroblasts (HF-NL). Methods: We measured inducible cyclooxygenase (COX)-2 gene and protein expression, and a profile of prostanoids at baseline and after IL-1 stimulation. Results: In both HF-IPF and HF-NL COX-2 expression was undetectable at baseline, but was significantly upregulated by IL-1. PGE(2) was the predominant COX product in IL-1-stimulated cells with no significant difference between HF-IPF and HF-NL (28.35 [9.09-89.09] vs. 17.12 [8.58-29.33] ng/10(6) cells/30 min, respectively; P = 0.25). TXB2 (the stable metabolite of TXA(2)) production was significantly higher in IL-1-stimulated HF-IPF compared to HF-NL (1.92 [1.27-2.57] vs. 0.61 [0.21-1.64] ng/10(6) cells/30 min, respectively; P = 0.007) and the ratio of PGI(2) (as measured by its stable metabolite 6-keto-PGF(1alpha)) to TXB2 was significantly lower at baseline in HF-IPF (0.08 [0.04-0.52] vs. 0.12 [0.11-0.89] in HF-NL; P = 0.028) and with IL-1 stimulation (0.24 [0.05-1.53] vs. 1.08 [0.51-3.79] in HF-NL; P = 0.09). Conclusion: An alteration in the balance of profibrotic and antifibrotic PGs in HF-IPF may play a role in the pathogeneses of IPF.