Exhaled eicosanoids following oral aspirin challenge in patients with asthma

Abstract

Rationale Since eicosanoids are involved in pathogenesis of asthma we hypothesized that their exhaled pattern may differ in various asthma phenotypes. Methods We measured cysteinyl leukotrienes (CysLTs) using radioimmunoassay, and prostaglandins E 2 and F 2α using GC-MS, in exhaled air condensates from patients with aspirin-induced asthma (AIA; n=13, age=40.6 ± 14.1 y., M/F=6/7), aspirin-tolerant asthma (n=18, age=35.8 ± 11.3, M/F=4/14) and healthy subjects (n=10, age=31.7 ± 10.3, M/F=6/4). The measurements were carried out at baseline and following aspirin challenge, and were coupled with urinary leukotriene E 4 (uLTE 4) estimations by ELISA. Results At baseline, the eicosanoid content in exhaled air did not differ between the groups. Following aspirin challenge, a rise in exhaled CysLTs was observed only in AIA (from 10.0 ± 10.3 to 36.5 ± 33.5 pg/ml; p=0.005). Only AIA patients had elevated uLTE 4 at baseline (2.97 ± 1.7 ng/mg creatinine; p=0.001), which increased further following aspirin provocation (9.8 ± 9.0; p=0.002). In AIA patients, there was an inverse relationship (Spearman's ρ=-0.7, p=0.008) between magnitude of CysLTs response to aspirin measured in exhaled air, as compared to urine. Conclusions 1) Measurement of eicosanoids in expiratory air condensates, though sensitive to detect CysLTs increase during aspirin challenge in AIA patients, offers no additional clinical advantage over uLTE 4 estimation. 2) Unexpected negative correlation between breath and urinary CysLTs responses awaits further inquires.