Serum Heme Oxygenase-1 Measurement is Useful for Evaluating Disease Activity and Outcomes in Patients With Acute Respiratory Distress Syndrome and Acute Exacerbation of Interstitial Lung Disease

Abstract

Background: Oxidative stress plays an important role in acute lung injury, which is associated with the development and progression of acute respiratory failure. Here, we investigated whether the degree of oxidative stress as indicated by serum heme oxygenase-1 (HO-1) is clinically useful for the patients with acute lung injury including ARDS and AE-ILDs.Methods: Serum HO-1 levels of newly diagnosed or untreated ARDS and AE-ILD patients were measured at diagnosis. Relationships between serum HO-1 and other clinical parameters and 1-month mortality were evaluated. Results: Fifty-five ARDS (n = 22) and AE-ILD (n = 33) patients were assessed. Serum HO-1 level at diagnosis was significantly higher in ARDS patients than AE-ILD patients (87.8 ± 60.0 ng/mL vs. 52.5 ± 36.3 ng/mL, P < 0.001). Serum HO-1 correlated with serum T-bil (R = 0.454, P < 0.001) and serum LDH (R = 0.500, P < 0.001). Serum HO-1 level significantly decreased from diagnosis to 2 weeks after diagnosis (81.1 ± 9.3 ng/mL vs. 60.9 ± 52.4 ng/mL, P = 0.016), however normalized. Composite parameters including serum HO-1, diagnosis, partial pressure of oxygen in arterial blood/fraction of inspired oxygen ratio, and sex for prediction of 1-month mortality showed a higher AUC (0.932) than did AUCs of a single predictor or combination of two or three predictors. Conclusion: Oxidative stress assessed by serum HO-1 is persistently high in patients with acute lung injury against intensive treatment. Also, serum HO-1 measurement could be clinically useful for evaluating disease activity and prognosis in patients with ARDS and AE-ILDs.