Abstract (249 words)
Background: Dysregulation of eicosanoids is associated with
asthma and a composite of oxylipins, including exhaled
LTB4, but their potential utility in monitoring the
therapeutic outcomes has not been comprehensively assessed.
Objectives: We aimed to examine the levels of major eicosanoids
representing different metabolic pathways in exhaled breath condensates
(EBCs) of children with asthma during exacerbation and after treatment.
Methods: Levels of 6 exhaled eicosanoid species in asthmatic
children and healthy subjects were evaluated using ELISA.
Results: In addition to those previously reported, including
LTB4, LTE4, LXA4 and
PGE2, the levels of exhaled 15-HETE, but not
TXB2, showed significant difference between asthmatics
(N=318) and healthy controls (N=97). When the asthmatic population was
stratified into different severity groups, the severe group was
characterized by significantly lower levels of 15-HETE and
15-HETE/LTB4 ratio, as compared to the mild and control
groups. Receiver Operating Characteristic (ROC) analyses revealed
similar distinguishing power for the level of exhaled 15-HETE and those
of FEV1 and FeNO. Analysis of asthmatics (N=75) during
exacerbation and convalescence showed significant improvement in lung
function (FEV1; p<0.001), but not FeNO,
concomitant with significantly increased levels of 15-HETE
(p<0.001) and reduced levels of TXB2(p<0.05) after therapy, particularly for those who at the top
30% level during exacerbation. Further, decreased LTB4and LXA4 at convalescence were noted only in those at
the top 30 percentile during exacerbation.
Conclusion: The exhaled 15-HETE was found to discriminate
childhood asthma while decreased levels of exhaled TXB2and increased levels of 15-HETE were prominent after treatment.
Keywords: childhood asthma, exhaled breath condensates
(EBCs), 15-HETE, TXB2