Exhaled ethane: an in vivo biomarker of lipid peroxidation in interstitial lung diseases.

BACKGROUND Oxidative stress plays a role in the pathogenesis and progression of interstitial lung disease (ILD). Exhaled ethane is a product of lipid peroxidation that has been proposed as a biomarker of oxidative stress in vivo. OBJECTIVES To determine whether the exhaled ethane level is elevated in patients with ILD and to compare it with other clinical parameters. METHODS Breath samples were collected from 34 patients with ILD, including 13 with idiopathic pulmonary fibrosis (IPF), 9 patients with cryptogenic organizing pneumonia, 6 patients with collagen vascular disease-associated interstitial pneumonia, and 6 patients with pulmonary sarcoidosis. Gas samples were obtained at hospital admission and after 3 weeks. After each expired sample was concentrated using a trap-and-purge procedure, the ethane level was analyzed by gas chromatography. RESULTS Exhaled ethane levels were elevated in ILD patients (n = 34, mean +/- SD, 8.5 +/- 8.0 pmol/dL) compared with healthy volunteers (n = 16, 2.9 +/- 1.0 pmol/dL; p < 0.001). Serial measurements revealed that increase and decrease of ethane levels were largely consistent with the clinical course. Four patients with IPF who had persistently high ethane levels died or deteriorated, whereas those with ethane levels < 5.0 pmol/dL remained stable or improved. Exhaled ethane concentrations were positively correlated with levels of lactate dehydrogenase (Spearman rank correlation coefficient [rs], 0.28, p = 0.026) and C-reactive protein (rs, 0.38, p = 0.025) and were inversely correlated with Pa(O2) (rs, - 0.40, p = 0.0026). Patients showing increased uptake on (67)Ga scintigraphy demonstrated higher ethane levels (n = 19, 7.5 +/- 5.7 pmol/dL) compared with those who did not show increased uptake on scintigraphy (n = 10, 3.0 +/- 2.4 pmol/dL; p < 0.01). CONCLUSIONS Exhaled ethane is elevated in patients with ILD and is correlated with the clinical outcome, suggesting that it provides useful information about ongoing oxidative stress, and thereby disease activity and severity in ILD.

[1]  B. Fischer,et al.  Interactions of oxygen radicals with airway epithelium. , 1994, Environmental health perspectives.

[2]  M. Kondo,et al.  EFFECTS OF REACTIVE OXYGEN SPECIES ON INTRACELLULAR CALCIUM IN BOVINE TRACHEAL EPITHELIUM: Modulation by Nitric Oxide , 2000, Experimental lung research.

[3]  C. Kneepkens,et al.  The hydrocarbon breath test in the study of lipid peroxidation: principles and practice. , 1992, Clinical and investigative medicine. Medecine clinique et experimentale.

[4]  Paul J. Friedman,et al.  American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. This joint statement of the American Thoracic Society (ATS), and the European Respiratory Society (ERS) was adopted by the ATS board of directors , 2002, American journal of respiratory and critical care medicine.

[5]  K. Brigham.  Role of free radicals in lung injury. , 1986, Chest.

[6]  H. Garewal,et al.  Cigarette smoking and ethane exhalation in humans. , 1995, American journal of respiratory and critical care medicine.

[7]  T. Risby,et al.  Utility of Breath Ethane as a Noninvasive Biomarker of Vitamin E Status in Children , 1991, Pediatric Research.

[8]  R. Crystal,et al.  Oxidant-mediated epithelial cell injury in idiopathic pulmonary fibrosis. , 1987, The Journal of clinical investigation.

[9]  W. MacNee,et al.  Systemic and pulmonary oxidative stress in idiopathic pulmonary fibrosis. , 1999, Free radical biology & medicine.

[10]  I. Horváth,et al.  "Haemoxygenase-1 induction and exhaled markers of oxidative stress in lung diseases", summary of the ERS Research Seminar in Budapest, Hungary, September, 1999. , 2001, The European respiratory journal.

[11]  C. Kneepkens,et al.  The potential of the hydrocarbon breath test as a measure of lipid peroxidation. , 1994, Free radical biology & medicine.

[12]  N. Shinomiya,et al.  Oxygen stress effects on proliferation rates and heat shock proteins in lymphocytes. , 2004, Aviation Space and Environmental Medicine.

[13]  S. Suzuki.  Probable lung injury by long-term exposure to oxygen close to 50 kilopascals. , 1994, Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc.

[14]  A. Mooradian,et al.  Effect of diabetes, insulin, and glucose load on lipid peroxidation in the rat. , 1994, Metabolism: clinical and experimental.

[15]  Kevin Gleeson,et al.  Detection of lung cancer with volatile markers in the breath. , 2003, Chest.

[16]  C. Cochrane.  Cellular injury by oxidants. , 1991, The American journal of medicine.

[17]  T. Okubo,et al.  Analysis of exhaled nitric oxide by the helium bolus method. , 2002, Chest.

[18]  P. Barnes,et al.  Elevation of exhaled ethane concentration in asthma. , 2000, American journal of respiratory and critical care medicine.

[19]  F. Viteri,et al.  A practical and reliable method for measuring ethane and pentane in expired air from humans. , 1999, Free radical biology & medicine.

[20]  I. Horváth,et al.  Heme oxygenase-1 induction and exhaled markers of oxidative stress in lung diseases , 2001 .

[21]  P. Barnes,et al.  Exhaled ethane, a marker of lipid peroxidation, is elevated in chronic obstructive pulmonary disease. , 2000, American journal of respiratory and critical care medicine.

[22]  David A. Lynch,et al.  Idiopathic pulmonary fibrosis: Diagnosis and treatment: International Consensus Statement , 2000 .