Exhaled leukotrienes and prostaglandins in asthma.
BACKGROUND
Most of the studies investigating the role of leukotrienes (LTs) and prostaglandins (PGs) in asthma have used invasive (eg, bronchoalveolar lavage fluid) or semi-invasive (eg, sputum induction) techniques. Others have measured eicosanoids in plasma or urine, probably reflecting systemic rather than lung inflammation. Collection of exhaled breath condensate (EBC) is a noninvasive method to collect airway secretions.


OBJECTIVE
We sought to investigate whether eicosanoids are measurable in EBC, to show possible differences in their concentrations in asthmatic patients and healthy subjects, and to investigate whether exhaled eicosanoids correlate with exhaled nitric oxide (NO), a marker of airway inflammation.


METHODS
Twelve healthy nonsmokers and 15 steroid-naive patients with mild asthma were studied. Subjects attended on one occasion for pulmonary function tests, collection of EBC, and exhaled NO measurements. Exhaled LTB(4)-like immunoreactivity, LTE(4)-like immunoreactivity, PGE(2)-like immunoreactivity, PGD(2)-methoxime, PGF(2)(alpha)-like immunoreactivity, and thromboxane B(2)-like immunoreactivity were measured by means of enzyme immunoassays.


RESULTS
LTE(4)-like immunoreactivity and LTB(4)-like immunoreactivity were detectable in EBC in healthy subjects, and their levels in asthmatic patients were increased about 3-fold (P <.0001) and 2-fold (P <.0005), respectively. Exhaled NO was increased in asthmatic patients compared with healthy subjects (P <.0001). There was a correlation between exhaled LTB(4) and exhaled NO (r = 0.56, P <.04) in patients with asthma. When measurable, prostanoid levels were similar in asthmatic patients and control subjects.


CONCLUSIONS
Exhaled LTE(4) and LTB(4) are increased in steroid-naive patients with mild asthma. EBC may be proved to be a novel method to monitor airway inflammation in asthma.
Montuschi
Paolo
P
Department of Pharmacology, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy.
Barnes
Peter J
PJ
D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D001944:Breath Tests; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007975:Leukotriene B4 / Q000032:analysis / Q000378:metabolism*; D017999:Leukotriene E4 / Q000032:analysis / Q000378:metabolism*; D008168:Lung / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism; D011453:Prostaglandins / Q000032:analysis / Q000378:metabolism*
D011453:Prostaglandins; D007975:Leukotriene B4; D009569:Nitric Oxide; D017999:Leukotriene E4