Oxidative stress and airway inflammation after allergen challenge evaluated by exhaled breath condensate analysis.
BACKGROUND
Allergen exposure may increase airway oxidative stress, which causes lipid membrane peroxidation and an increased formation of 8-isoprostane.


OBJECTIVE
The aim of the study was to investigate oxidative stress induced by allergen challenge in mild asthmatics, by measuring 8-isoprostane in exhaled breath condensate (EBC), and to examine their relationship with mediators derived from arachidonic acid. Methods 8-isoprostane, cysteinyl leukotrienes (cys-LTs) and prostaglandin E2 (PGE(2) ) concentrations in EBC were measured at baseline and after allergen challenge in 12 patients with mild allergic asthma sensitized to cat allergen.


RESULTS
At 24 h after allergen challenge, compared with baseline values, EBC 8-isoprostane increased [48.64 pg/mL (44.14-53.61) vs. 21.56 pg/mL (19.92, 23.35), P<0.001], cys-LTs increased [27.37 pg/mL (24.09-31.10) vs. 13.28 pg/mL (11.32, 15.57), P<0.001] and PGE(2) decreased [18.69 pg/mL (12.26, 28.50) vs. 39.95 pg/mL (34.37, 46.43), P<0.001]. The trend of increasing 8-isoprostane after allergen challenge was significantly correlated with the trend of increasing cys-LTs (R(2) =0.85, P<0.001) whereas the trend of decreasing PGE(2) after allergen challenge was significantly correlated with the trend of increasing cys-LTs (R(2) =0.52, P=0.001).


CONCLUSIONS
The increase in EBC 8-isoprostane observed after allergen challenge indicates that allergen exposure increases airway oxidative stress in allergic asthma. The strict correlation between cys-LTs and 8-isoprostane underlines the relationship between allergic inflammation and oxidative stress. A shift of arachidonic acid metabolism towards lipoxygenase pathway is induced by the allergen challenge. Airway oxidative stress occurs after allergen challenge even in patients with mild intermittent allergic asthma.
Brussino
L
L
Department of Biomedical Sciences and Human Oncology, Allergy and Clinical Immunology, University of Torino & AO Mauriziano Umberto I, Largo Turati 62, Turin, Italy.
Badiu
I
I
Sciascia
S
S
Bugiani
M
M
Heffler
E
E
Guida
G
G
Malinovschi
A
A
Bucca
C
C
Rolla
G
G
D000280:Administration, Inhalation; D000328:Adult; D000485:Allergens / Q000008:administration & dosage*; D000818:Animals; D001249:Asthma / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D016022:Case-Control Studies; D002415:Cats; D015237:Dinoprost / Q000031:analogs & derivatives / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D015289:Leukotrienes / Q000378:metabolism; D015227:Lipid Peroxidation; D008168:Lung / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult
D000485:Allergens; D015415:Biomarkers; D015289:Leukotrienes; C075750:8-epi-prostaglandin F2alpha; D009569:Nitric Oxide; D015237:Dinoprost; D015232:Dinoprostone