3-Nitrotyrosine, a marker of nitrosative stress, is increased in breath condensate of allergic asthmatic children.
BACKGROUND
Asthmatic patients have high exhaled nitric oxide (NO) levels. NO-mediated inflammatory actions are mainly due to NO conversion into reactive nitrogen species, which can lead to nitrotyrosine formation. The aim of this study was to assess 3-nitrotyrosine (3-NT) levels in exhaled breath condensate (EBC) of asthmatic and healthy children and to investigate whether there is any relationship with exhaled NO (FE(NO)) and lung function.


METHODS
The study included 20 asthmatic children (10 steroid-naive with intermittent asthma, 10 steroid-treated with unstable persistent asthma) and 18 healthy controls. They underwent FE(NO) measurement, EBC collection and spirometry. 3-NT was measured by a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in isotopic dilution.


RESULTS
The median EBC concentration of 3-NT (expressed as nitrotyrosine/tyrosine ratio x 100) in asthmatic children was fivefold higher than in healthy subjects [0.23% (0.12-0.32) vs 0.04% (0.02-0.06), P < 0.001] with no difference between steroid-naive and unstable steroid-treated asthmatic patients. FE(NO) levels were higher in asthmatic [44.6 ppb (36.0-66.0)] than in healthy children [7.5 ppb (6.0-8.8), P < 0.001]. No correlation was found among 3-NT, FE(NO) and lung function parameters.


CONCLUSIONS
Nitrotyrosine is high in EBC of asthmatic children and could be considered as a noninvasive marker of nitrosative events in the airways.
Baraldi
E
E
Department of Pediatrics, University of Padova, Padova, Italy.
Giordano
G
G
Pasquale
M F
MF
Carraro
S
S
Mardegan
A
A
Bonetto
G
G
Bastardo
C
C
Zacchello
F
F
Zanconato
S
S
D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D011336:Probability; D012016:Reference Values; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013147:Spirometry / Q000379:methods; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis
D018927:Anti-Asthmatic Agents; D015415:Biomarkers; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine