Novel approach for analysis of bronchoalveolar lavage fluid (BALF) using HPLC-QTOF-MS-based lipidomics: Lipid levels in asthmatics and corticosteroid-treated asthmatic patients

To better understand the respiratory lipid phenotypes of asthma, we developed a novel method for lipid profiling of bronchoalveolar lavage fluid (BALF) using HPLC-QTOF-MS with an internal spectral library and high-throughput lipid-identifying software. The method was applied to BALF from 38 asthmatic patients (18 patients with nonsteroid treated bronchial asthma [NSBA] and 20 patients with steroid treated bronchial asthma [SBA]) and 13 healthy subjects (NC). We identified 69 lipids, which were categorized into one of six lipid classes: lysophosphatidylcholine (LPC), phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylserine (PS), sphingomyelin (SM) and triglyceride (TG). Compared with the NC group, the individual quantity levels of the six classes of lipids were significantly higher in the NSBA subjects. In the SBA subjects, the PC, PG, PS, SM, and TG levels were similar to the levels observed in the NC group. Using differentially expressed lipid species (p value < 0.05, FDR < 0.1 and VIP score of PLS-DA > 1), 34 lipid biomarker candidates with high prediction performance between asthmatics and controls were identified (AUROC > 0.9). These novel findings revealed specific characteristics of lipid phenotypes in asthmatic patients and suggested the importance of future research on the relationship between lipid levels and asthma.