Targeted eicosanoids lipidomics of exhaled breath condensate in healthy subjects

Background d breath condensate collection is a non-invasive method of sampling the respiratory tract that can be repeated several times in a wide range of clinical settings. Quantitation of non-volatile compounds in the condensate requires highly sensitive analytical methods, e.g. mass spectrometry. ive idate cross-platform measurements of eicosanoids using high performance liquid chromatography or gas chromatography coupled with mass spectrometry in exhaled breath condensate sampled from 58 healthy individuals. s different eicosanoid compounds, representing major arachidonic acid lipoxygenation and cyclooxygenation pathways were measured using a stable isotope dilution method. We applied a free palmitic acid concentration as a surrogate marker for the condensate dilution factor. s noids concentrations in the condensates were consistent with their content in other biological fluids. Prostaglandin E2 was the most abundant mediator, represented by its stable metabolite tetranor-PGEM. Prostaglandin D2 products were at low concentration, while hydroxyacids derived from lipoxygenation were abundant. 5-HETE was elevated in current tobacco smokers. Leukotriene B4 has the highest concentration of all 5-LO products. 15-LO analogues of cysteinyl leukotrienes–eoxins were detectable and metabolized to eoxin E4. Two main vascular prostanoids: prostacyclin and thromboxane B2 were present as metabolites. A marker for non-enzymatic lipid peroxidation, 8-iso-PGF2α isoprostane was increased in smokers. sion ted targeted lipidomics analysis of exhaled breath condensate in healthy subjects justifies its application to investigation of inflammatory lung diseases. Measurements of non-volatile mediators of inflammation in the condensates might characterize disease-specific pathological mechanisms and responses to treatment.