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Refinement of metabolite detection in cystic fibrosis sputum reveals heme correlates with lung function decline

Glasser, Nathaniel R. and Hunter, Ryan C. and Liou, Theodore G. and Newman, Dianne K. (2019) Refinement of metabolite detection in cystic fibrosis sputum reveals heme correlates with lung function decline. PLoS ONE, 14 (12). Art. No. e0226578. ISSN 1932-6203. PMCID PMC6919587. doi:10.1371/journal.pone.0226578.

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The bacterial growth environment within cystic fibrosis (CF) sputum is complex, dynamic, and shaped by both host and microbial processes. Characterization of the chemical parameters within sputum that stimulate the in vivo growth of airway pathogens (e.g. Pseudomonas aeruginosa) and their associated virulence factors may lead to improved CF treatment strategies. Motivated by conflicting reports of the prevalence and abundance of P. aeruginosa-derived metabolites known as phenazines within CF airway secretions, we sought to quantify these metabolites in sputum using quadrupole time-of-flight mass spectrometry. In contrast to our previous work, all phenazines tested (pyocyanin (PYO), phenazine-1-carboxylic acid (PCA), phenazine-1-carboxamide, and 1-hydroxyphenazine) were below detection limits of the instrument (0.1 μM). Instead, we identified a late-eluting compound that shared retention time and absorbance characteristics with PCA, yet generated mass spectra and a fragmentation pattern consistent with ferriprotoporphyrin IX, otherwise known as heme B. These data suggested that UV-vis chromatographic peaks previously attributed to PCA and PYO in sputum were mis-assigned. Indeed, retrospective analysis of raw data from our prior study found that the heme B peak closely matched the peaks assigned to PCA, indicating that the previous study likely uncovered a positive correlation between pulmonary function (percent predicted forced expiratory volume in 1 second, or ppFEV1) and heme B, not PCA or any other phenazine. To independently test this observation, we performed a new tandem mass-spectrometry analysis of 71 additional samples provided by the Mountain West CF Consortium Sputum Biomarker study and revealed a positive correlation (ρ = −0.47, p<0.001) between sputum heme concentrations and ppFEV1. Given that hemoptysis is strongly associated with airway inflammation, pulmonary exacerbations and impaired lung function, these new data suggest that heme B may be a useful biomarker of CF pathophysiology.

Item Type:Article
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URLURL TypeDescription CentralArticle Paper
Glasser, Nathaniel R.0000-0002-2833-5166
Hunter, Ryan C.0000-0003-3841-1676
Liou, Theodore G.0000-0003-0121-4847
Newman, Dianne K.0000-0003-1647-1918
Alternate Title:Refinement of metabolite detection in cystic fibrosis sputum reveals heme negatively correlates with lung function
Additional Information:© 2019 Glasser et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: August 26, 2019; Accepted: November 28, 2019; Published: December 18, 2019. The MWCFC Sputum Biomarker investigators included Frederick R Adler, Fadi Asfour, Barbara A Chatfield, Jessica A Francis, John R Hoidal, Judy L Jensen, Yanping Li, Theodore G Liou, Kristyn A Packer, Jane Vroom (University of Utah); Natalia Argel, Peggy Radford (Phoenix Children’s Hospital); Perry S Brown, Dixie Durham (St. Luke’s Cystic Fibrosis Center of Idaho); Cori L Daines, Osmara Molina (University of Arizona); Barbara Glover, Craig Nakamura, Ryan Yoshikawa (Cystic Fibrosis Center, Las Vegas); Theresa Heynekamp, Abby J Redway (University of New Mexico); Ruth Keogh (London School of Hygiene and Tropical Medicine); Carol M Kopecky, Scott D Sagel (Children's Hospital Colorado, University of Colorado School of Medicine); Noah Lechtzin (Johns Hopkins University School of Medicine); Jerimiah Lysinger, Shawna Sprandel (Montana Cystic Fibrosis Center, Billings Clinic); Katie R Poch, Jennifer L Taylor-Cousar (National Jewish Health); Alexandra L Quittner (Miami Children's Research Institute, Nicklaus Children's Hospital); John P Clancy (University of Cincinnati); J Stuart Elborn (Queen’s University, Belfast and Royal Brompton Hospital, London); Kenneth N Olivier (Laboratory of Chronic Airway Infection, Pulmonary Branch, National Heart Lung and Blood Institute, National Institutes of Health). All MWCFC Correspondence should be addressed to Theodore G. Liou ( We thank Dr. Nathan Dalleska at the Environmental Analysis Center (Caltech) for analytical support. MWCFC work was supported by grants from the Cystic Fibrosis Foundation (LIOU13A0, LIOU14Y4), the National Center for Advancing Translational Science at the NIH (NCATS/NIH 8UL1TR000105 [formerly UL1RR025764]), the Ben B and Iris M Margolis Foundation of Utah and the Claudia Ruth Goodrich Stevens Endowment Fund. This work was also supported by grants to DKN from the NIH (5R01HL117328-03 and 1R01AI127850-01A1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Data Availability: All relevant data are within the paper. Author Contributions: Conceptualization: Nathaniel R. Glasser, Dianne K. Newman. Data curation: Nathaniel R. Glasser, Ryan C. Hunter, Theodore G. Liou. Formal analysis: Nathaniel R. Glasser, Ryan C. Hunter, Theodore G. Liou, Dianne K. Newman. Funding acquisition: Theodore G. Liou, Dianne K. Newman. Investigation: Nathaniel R. Glasser, Theodore G. Liou, Dianne K. Newman. Methodology: Nathaniel R. Glasser. Project administration: Ryan C. Hunter, Theodore G. Liou, Dianne K. Newman. Supervision: Dianne K. Newman. Validation: Nathaniel R. Glasser. Writing – original draft: Nathaniel R. Glasser, Ryan C. Hunter, Theodore G. Liou, Dianne K. Newman. Writing – review & editing: Nathaniel R. Glasser, Ryan C. Hunter, Theodore G. Liou, Dianne K. Newman. The authors have declared that no competing interests exist.
Group:Division of Geological and Planetary Sciences
Funding AgencyGrant Number
Cystic Fibrosis FoundationLIOU13A0
Cystic Fibrosis FoundationLIOU14Y4
Ben B. and Iris M. Margolis FoundationUNSPECIFIED
Claudia Ruth Goodrich Stevens Endowment FundUNSPECIFIED
Issue or Number:12
PubMed Central ID:PMC6919587
Record Number:CaltechAUTHORS:20181128-093526010
Persistent URL:
Official Citation:Glasser NR, Hunter RC, Liou TG, Newman DK, for the Mountain West CF Consortium Investigators (2019) Refinement of metabolite detection in cystic fibrosis sputum reveals heme correlates with lung function decline. PLoS ONE 14(12): e0226578.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91271
Deposited By: George Porter
Deposited On:28 Nov 2018 18:01
Last Modified:01 Jun 2023 23:48

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