2. Department of Otolaryngology, Jagiellonian University Medical College, ul. Śniadeckich 2, 31-501 Krakow, Poland.
Background: Histamine is used as a direct stimulus to measure airway responsiveness. This short-acting biogenic amine acts mainly on airway smooth muscle receptors causing bronchoconstriction and is used for the airway hyperresponsiveness assessment in asthmatic patients. In aspirin-induced asthma (AIA) special regulatory role of eicosanoids is postulated. The aim of the study was to assess the influence of histamine on a wide profile of eicosanoids measured in exhaled breath condensate (EBC) in AIA patients and asthmatics tolerating aspirin well (ATA).
Methods: The study population consisted of seventeen asthmatics. Ten of them were AIA patients. Eicosanoid concentrations in EBC were determined using gas chromatography/mass spectrometry or high-performance liquid chromatography/tandem mass spectrometry. Measurements were performed at baseline and following bronchial histamine challenge.
Results: Bronchial reactions were precipitated by histamine in all patients and accompanied only by decrease of leukotriene (LT) C4 and trans-LTC4 mean level. The AIA group was characterized by higher levels of cysteinyl leukotrienes, LTC4, and prostaglandin (PG) E2 in EBC at baseline, and decrease in EBC concentration of LTC4, trans-LTC4 and tetranor-PGE-M following histamine challenge. In the ATA group no significant changes in eicosanoids levels after histamine were noticed.
Conclusions: AIA patients present different baseline profile of EBC eicosanoids in comparison to patients with ATA. Histamine administered locally during a bronchial challenge test may influence inflammatory mediators and thus trigger indirect effects in the respiratory tract. This response for histamine differentiates two studied phenotypes of asthma; only in the AIA group histamine precipitates alterations of the eicosanoid synthesis in the lungs.
Keywords: Aspirin, asthma, hypersensitivity, eicosanoids, histamine