title: 3-Chlorotyrosine in sputum of COPD patients: relationship with airway inflammation.
abstract: The airways of patients with chronic obstructive pulmonary disease (COPD) are associated with increased numbers of inflammatory cells, in particular neutrophils and macrophages. Contained within the primary granules of neutrophils is the heme enzyme called myeloperoxidase (MPO) that has been used as a biomarker of neutrophilic inflammation in COPD and other inflammatory diseases. MPO is the only enzyme in the body that produces hypochlorous acid (HOCl), which effectively chlorinates tyrosine residues in proteins. The presence of 3-chlorotyrosine (3Cl-Tyr) in sputum of COPD patients has yet to be established. Spontaneously produced sputum was collected from 14 stable COPD patients, and ultra-centrifuged to prepare sol phase samples for analysis. Sputum 3Cl-Tyr levels were measured using Mass Spectrometry (LC-MSMS). Sputum MPO activity was measured using a standard chromogenic substrate assay. The Spearman rank correlation was used to analyse the data. We report for the first time the measurement of 3Cl-Tyr in sputum from stable COPD patients. The sputum levels of 3Cl-Tyr correlated well with sputum MPO activity (r = 0.88; p < 0.0001). The presence of 3Cl-Tyr in the sputum of stable COPD patients suggests an active process related to MPO that may play a role in the pathophysiology of this disease.
authors.affiliation: DMPK, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leicestershire LE11 5RH, United Kingdom. CharlesJO'Donnell@astrazeneca.com
authors.forename: Charles
authors.initials: C
authors.lastname: O'Donnell
authors.forename: Paul
authors.initials: P
authors.lastname: Newbold
authors.forename: Peter
authors.initials: P
authors.lastname: White
authors.forename: Bob
authors.initials: B
authors.lastname: Thong
authors.forename: Helen
authors.initials: H
authors.lastname: Stone
authors.forename: Robert A
authors.initials: RA
authors.lastname: Stockley
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002470:Cell Survival; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism*; D013183:Sputum / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D014443:Tyrosine; D009195:Peroxidase; C087259:3-chlorotyrosine