Targeted eicosanoids lipidomics of exhaled breath condensate in healthy subjects.

BACKGROUND: Exhaled 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. OBJECTIVE: To validate 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. METHODS: Twenty 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. RESULTS: Eicosanoids concentrations in the condensates were consistent with their content in other biological fluids. Prostaglandin E(2) was the most abundant mediator, represented by its stable metabolite tetranor-PGEM. Prostaglandin D(2) products were at low concentration, while hydroxyacids derived from lipoxygenation were abundant. 5-HETE was elevated in current tobacco smokers. Leukotriene B(4) has the highest concentration of all 5-LO products. 15-LO analogues of cysteinyl leukotrienes-eoxins were detectable and metabolized to eoxin E(4). Two main vascular prostanoids: prostacyclin and thromboxane B(2) were present as metabolites. A marker for non-enzymatic lipid peroxidation, 8-iso-PGF(2alpha) isoprostane was increased in smokers. CONCLUSION: Presented 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.

A controlled study of 9alpha,11beta-PGF2 (a prostaglandin D2 metabolite) in plasma and urine of patients with bronchial asthma and healthy controls after aspirin challenge.

BACKGROUND: Prostaglandin D(2) (PGD(2)) is the predominant cyclooxygenase product of mast cells, the number of which is increased in bronchial asthma. Release of PGD(2) might reflect mast cell activation and disordered function of the asthmatic lung. OBJECTIVE: We sought to determine blood and urinary levels of 9alpha,11beta-PGF(2), a major stable PGD(2) metabolite in 2 well-defined phenotypes of asthma, aspirin-induced asthma (AIA) and aspirin-tolerant asthma (ATA), and in healthy control subjects and to study the effects of aspirin on PGD(2) release. METHODS: Using gas chromatography/mass spectrometry, we determined plasma and urinary concentrations of 9alpha,11beta-PGF(2) at baseline in 131 stable asthmatic patients, 65 of whom had AIA and 66 of whom had ATA. Fifty healthy nonatopic subjects served as the control group. The measurements were also performed after an aspirin challenge in 26 of 65 patients with AIA and in 24 of 50 control subjects. RESULTS: At baseline, patients with AIA had significantly higher plasma levels of 9alpha,11beta-PGF(2) than either patients with ATA or healthy subjects. A similar significant elevation of serum tryptase was observed in patients with AIA compared with patients with ATA and control subjects. Mean urinary 9alpha,11beta-PGF(2) values did not differ among the 3 groups. In patients with AIA, as opposed to healthy subjects, aspirin challenge invariably precipitated a clinical reaction, accompanied in most patients by a further rise in plasma levels of PGD(2) metabolite and tryptase. CONCLUSIONS: In stable AIA, though not in ATA, there is a steady release of PGD(2) into the blood, accompanied by the release of tryptase. Aspirin enhances this reaction in most patients. Release of bronchoconstrictive PGD(2) might contribute to the severe clinical course of AIA.