Exhaled cysteinyl-leukotrienes and 8-isoprostane in patients with asthma and their relation to clinical severity.

BACKGROUND

Collection of exhaled breath condensate (EBC) is a safe, non-invasive method to collect droplets of the airway surface liquid and measure mediators of airway inflammation and oxidative stress, such as cysteinyl-leukotrienes (cys-LTs) and 8-isoprostane.

OBJECTIVE

The aim of our study was to investigate baseline values of inflammatory lipid mediators in EBC and their relation to asthma severity.

METHODS

Nineteen healthy subjects, 16 mild, 12 moderate and 15 severe asthmatics were studied. All subjects attended a clinic visit for spirometry and EBC collection. The concentrations of exhaled cys-LTs and 8-isoprostane were measured by means of specific enzyme immunoassays.

RESULTS

8-isoprostane levels were significantly increased in mild (49.1+/-5.2 pg/mL, p<0.001), moderate (49.7+/-5.2 pg/mL, p<0.001) and severe asthmatics (77.7+/-7.3 pg/mL, p<0.001), compared to healthy controls (16.4+/-1.6 pg/mL). Moreover, 8-isoprostane levels were significantly higher in severe compared to mild and moderate asthmatics (p<0.01). Cys-LT levels were significantly higher in moderate (34.6+/-4.4 pg/mL, p<0.05) and severe asthmatics (47.9+/-6.0 pg/mL, p<0.001), while no significant difference was found between healthy controls and mild asthmatics. 8-isoprostane levels in EBC of asthmatics strongly correlated with cys-LT levels (r=0.61, p<0.0001).

CONCLUSIONS

8-isoprostane and cys-LT are detectable in EBC of healthy subjects and their levels progressively increase in asthmatic patients according to disease severity. The correlation found between these two lipid mediators indicating a link between oxidative stress and airway inflammation.