PAFAH2 and fibrosis: 19,20-EpDPE administrations significantly improved PH by suppressing advanced pulmonary vascular remodeling including perivascular fibrosis both in the WT mice and in the Pafah2 KO mice, but DHA or ω-6 epoxide, 14,15-EET, did not exhibit the beneficial effects (Fig. 5a–d, Supplementary Fig. 10a–d).