Sputum metabolomic profiling of bronchial asthma based on quadruple time-of-flight mass spectrometry.

To improve diagnosis of asthma, we tend to confirm potential biomarkers by comparing sputum metabolome profiles between asthma patients and healthy controls, using ultra-high-performance liquid chromatography coupled to quadruple time-of-flight mass spectrometry (UHPLC-QTOF/MS). Thirty endogenous metabolites contributing to the separation of asthma patients and healthy controls were tentatively identified in positive mode, such as 1-hexadecanoyl-sn-glycerol, glycerol 1-stearate, sphingosine, Phe-Ser, Tyr-Ala and Phe-Gln, and 12 endogenous metabolites were identified in negative mode, such as cytidine 2',3'-cyclic phosphate, 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phospho-(1'-rac-glycerol), 1-octadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phosphoserine, thymidine, gamma-L-glutamyl-L-valine and adenine. Those differential metabolites were mainly participatedin glycerophospholipid metabolism, retrograde endocannabinoid signaling and metabolic pathways in positive mode and 2-oxocarboxylic acid metabolism, biosynthesis of amino acids, phenylalanine, tyrosine and tryptophan biosynthesis, valine, leucine and isoleucine degradation and metabolic pathways in negative mode. Importantly, several metabolic pathways including glycerophospholipid metabolism, inositol phosphate metabolism, and glycolysis or gluconeogenesis were found most important. These findings suggest sputum metabolomics can be used for the early diagnosis and risk prediction of asthma. IJCEP