Exhaled markers of oxidative stress in idiopathic pulmonary fibrosis

Authors


  • Department of Pneumonology (K. Psathakis, S. Loukides, P. Panagou) and the Clinical Research Unit (G. Papatheodorou), Army General Hospital of Athens, Athens; 3rd Department of Pneumonology, Sismanoglion Hospital of Athens, Athens (D. Mermigkis, V. Polychronopoulos); Department of Pneumonology, University Hospital of Heraklion, Medical School University of Crete, Heraklion (N. M. Siafakas); University Hospital of Alexandroupolis, Medical School University of Thrace, Alexandroupolis (D. Bouros), Greece.

Kostas Psathakis, MD, Department of Pneumonology, Army General Hospital of Athens, Liakataion 15, 11474, Gyzi, Athens, Greece. Tel.:/fax: +30 2106435278; e-mail: kpsazakis@hol.gr

Abstract

Background  Expired breath condensate (EBC) has never been used to explore the level of oxidative stress in idiopathic pulmonary fibrosis (IPF). Therefore, the aim of this study was to measure the levels of H2O2 and 8-isoprostane, as biomarkers of oxidative stress, in the EBC of patients with IPF.

Materials and methods  We investigated 16 patients with IPF and 15 healthy subjects as the control group. The levels of H2O2 and 8-isoprostane were measured in the EBC of all subjects and were compared between the IPF and control groups. In patients with IPF, H2O2 and 8-isoprostane were further correlated with pulmonary function tests (PFTs), the resting pO2 and the differential cell count from the bronchoalveolar lavage fluid (BALF).

Results  The mean (95%CI) concentration of H2O2 was increased in the patients with IPF compared with the normal subjects (0·36, 0·24–0·47 µM vs. 0·16, 0·10–0·23 µM, P = 0·003). The mean (95%CI) concentration of 8-isoprostane was also increased in the patients with IPF compared with the controls (74, 38–110 pg mL−1 vs. 33, 28–39 pg mL−1, P = 0·02). In the patients with IPF, the diffusing capacity of the lung for carbon monoxide was negatively correlated with the levels of H2O2 in EBC (P = 0·03, r = −0·58). No other correlation was found between the oxidative stress markers in the EBC and PFT values, pO2 or BALF cell count.

Conclusions  Our data suggest that H2O2 and 8-isoprostane are increased in the EBC of patients with IPF. H2O2 may be correlated with the severity of the disease in IPF.

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