Kline, Jeffrey A.Steuerwald, Nury M.Watts, John A.Courtney, MarkBonkovsky, Herbert L.2016-12-152016-12-152015-10Kline, J. A., Steuerwald, N. M., Watts, J. A., Courtney, M., & Bonkovsky, H. L. (2015). Leukocyte expression of heme oxygenase-1 [hmox1] varies inversely with severity of tricuspid regurgitation in acute pulmonary embolism. Thrombosis Research, 136(4), 769–774. https://doi.org/10.1016/j.thromres.2015.08.0170049-3848 1879-2472https://hdl.handle.net/1805/11619Objective: Pulmonary embolism (PE) can cause intracardiac hemolysis and increased plasma hemoglobin and arginase-1, which can worsen pulmonary vasoconstriction. We test the hypothesis that patients with PE that causes tricuspid regurgitation (TR), indicative of higher pulmonary arterial pressures, have decreased leukocyte expression of hmox-1 compared with patients with PE and no TR and patients without PE. Design: Prospective, noninterventional study. Patients: Normotensive patients with suspected PE (n=87) who underwent CT pulmonary angiography and transthoracic Doppler-echocardiography. Measurements: Significant TR was defined as a jet velocity > 2.7m/s. Leukocyte expression of hmox-1, haptoglobin, haptoglobin related gene, the haptoglobin receptor, CD163 and cox-2 genes were assessed by quantitative rtPCR, and the hmox-1 promoter was examined for the −413 A→T SNP and GT repeat polymorphisms. Results: Of the 44 (50%) with PE+, 22 had TR+, and their mean pulmonary vascular occlusion (39±32%) did not differ significantly from patients who were TR− (28±26%, P=0.15). Patients with PE+ and TR+ had significantly lower expression of hmox-1 and haptoglobin genes than patients without PE+ and no TR. Expression of hmox-1 varied inversely with TR velocity (r2=0.45, P<0.001) for PE+ (n=22) but not patients without PE. Hmox-1 expression did not vary significantly with genotype. Cox-2 did not differ between groups and had no correlation with TR. Conclusions: Severity of TR varied inversely with hmox-1 expression, suggesting that hmox-1 expression affects pulmonary vascular reactivity after PE.en-USPublisher's PolicyFibrinolysisHaptoglobinHeme oxygenaseHemolysisPulmonary hypertensionArticle