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Elevation of nitrotyrosine and nitrate concentrations in cystic fibrosis sputum
Author(s) -
Jones Kimberly L.,
Hegab Alaa H.,
Hillman Bettina C.,
Simpson Keith L.,
Jinkins Patricia A.,
Grisham Matthew B.,
Owens Michael W.,
Sato Etsuro,
Robbins Richard A.
Publication year - 2000
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/1099-0496(200008)30:2<79::aid-ppul1>3.0.co;2-1
Subject(s) - nitrotyrosine , peroxynitrite , nitrite , sputum , cystic fibrosis , nitric oxide , myeloperoxidase , nitrate , medicine , exhaled breath condensate , superoxide , immunology , endocrinology , pathology , biochemistry , chemistry , asthma , nitric oxide synthase , inflammation , enzyme , tuberculosis , organic chemistry
Nitric oxide (NO) is increased in the exhaled air of some patients with inflammatory lung disorders, but not in others. NO may combine with superoxide to form peroxynitrite, which lowers NO gas concentrations, increases formation of nitrate, and increases nitration of tyrosine residues on proteins. We hypothesized that superoxide released from neutrophils in the lower respiratory tract of cystic fibrosis (CF) results in increased nitrate and nitrotyrosine levels in sputum. In order to test this hypothesis, exhaled NO was collected from 5 stable adult CF subjects and from 5 nonsmoking normal controls. Consistent with previous reports, exhaled NO concentrations were not increased in CF exhaled air (22.6 ± 1.5 ppb vs. 28.6 ± 1.5 ppb in normals, P > 0.05). Sputum was collected from 9 adult CF subjects and the same 5 normal controls and evaluated for nitrite, nitrate, and nitrotyrosine. Nitrate and nitrotyrosine levels, but not nitrite, were significantly elevated in CF. Recently, myeloperoxidase has also been implicated as a mechanism of nitrotyrosine formation. Therefore, myeloperoxidase was measured and found to be elevated in the CF sputum (64.2 ± 35.9 vs. 0.73 ± 0.16 U/mL, P < 0.001), and was found to correlate with concentrations of nitrotyrosine (r = 0.87, P < 0.05). However, in vitro studies with myeloperoxidase and murine lung epithelial cells did not demonstrate a reduction of NO gas with nitrotyrosine or an increase in nitrate formation. These data demonstrate that nitrate and nitrotyrosine are elevated in the sputa of CF subjects and suggest increased production of NO in the lower respiratory tract of CF patients, despite the relatively low exhaled NO levels. Pediatr Pulmonol. 2000; 30:79–85. Published 2000 Wiley‐Liss, Inc.