Determination of thiocyanate in exhaled breath condensate

• Type of Material: Article
• Authors: Joshua Chandler, Emory University; Hamed Horati, Erasmus MC; Douglas Walker, Emory University; Enea Pagliano, National Research Council of Canada; Rabindra Tirouvanziam, Emory University; Mieke Veltman, Erasmus MC; Bob J. Scholte, Erasmus MC; Hettie M. Janssens, Erasmus MC; Young-Mi Go, Emory University; Dean Jones, Emory University
• Language: English
• Date: 2018-10-01
• Publisher: ELSEVIER SCIENCE INC
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2018 Elsevier Inc.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.freeradbiomed.2018.08.012
• Title of Journal or Parent Work: FREE RADICAL BIOLOGY AND MEDICINE
• Volume: 126
• Start Page: 334
• End Page: 340
• Grant/Funding Information: This study was supported in part by R01 ES023485 (DPJ, YMG), R21 ES025632 (DPJ, YMG), P30 ES019776 (DPJ), U2C ES026560 (DPJ); R01 MH107205 (DPJ, DIW); NHLBI F32 HL132493 (JDC), CFF CHANDL16F0 (JDC); and NHLBI R01 HL126603 (RT, HMJ, BJS).
• Keywords: Life Sciences & Biomedicine; PLASMA; Antioxidant; Biomarkers; Science & Technology; Biochemistry & Molecular Biology; UREA; BRONCHOALVEOLAR LAVAGE; Clinical chemistry; HOST-DEFENSE; Redox; HYDROGEN-PEROXIDE; SYSTEM; LACTOPEROXIDASE; Endocrinology & Metabolism; Myeloperoxidase; THYROID-FUNCTION; CYSTIC-FIBROSIS; MASS-SPECTROMETRY
• Research Categories: Biology, Molecular; Chemistry, Biochemistry

Abstract

Thiocyanate is a heme peroxidase substrate that scavenges oxidants produced during inflammation and regulates host defense. In cystic fibrosis (CF) patients, increased airway thiocyanate levels are associated with improved lung function. Research on airway thiocyanate is limited, however, because convenient non-invasive airway sampling methods, such as exhaled breath condensate (EBC), yield low concentrations that are difficult to detect with available assays. In the present study, we developed a method for the determination of thiocyanate in dilute samples using isotope dilution headspace gas chromatography-coupled high-resolution, accurate-mass mass spectrometry (GC-HRMS). The method reliably quantified as little as 4 pmol thiocyanate in EBC and could detect even lower amounts. We successfully measured thiocyanate in EBC from seven healthy donors, with a mean ± SD of 27 ± 16 nM and a median inter-assay coefficient of variation of 10.4% over six months. The method was applied to other biological fluids (plasma from the same visit as EBC donation; bronchoalveolar lavage fluid [BALF] from infants with CF; and healthy adult mouse BALF), giving reliable quantification of samples ranging from 10 nM to 100 µM. Thiocyanate concentrations in fluids besides EBC were (from lowest to highest): 0.73 ± 0.39 µM in BALF of healthy adult mice (n = 6); 1.4 ± 1.4 µM in BALF from infants with CF (n = 24); 46 ± 22 µM in the plasma of adult volunteers (n = 7). These results demonstrate the utility of this new method for clinical determination of thiocyanate in EBC and other biological fluids.