Phospholipid composition of the respiratory tract lining fluid (RTLF) in subjects with Asthma and COPD

Phospholipids are the main component of surfactant in RTLF. Change in phospholipid composition in relation to respiratory diseases has rarely been studied. Thus, we aimed to investigate differences in the phospholipid profiles of small airways in subjects with physician-diagnosed asthma (n=39), those with COPD defined as symptoms of breathlessness+postbronchodilatory FEV1/FVC< 0.7 (n=36) and healthy controls (n=44). <bold>Methods:</bold> Subjects were recruited from the SCAPIS-study, all currently being non-smokers. RTLF was collected by the PExA method1 and phospholipids were analyzed by Liquid Chromatography with tandem mass spectrometry. Differences among the groups were tested by Kruskal-Wallis and Post-hoc (p<0.05). <bold>Results:</bold> In total, 90 phospholipid species were quantified, belonging to 8 lipid-classes. Of these, 5 classes (Ether-linked phosphatidyl-ethanolamine (PE O); phosphatidylcholine (PC); phosphatidylethanolamine (PE); phosphatidylglycerols (PG); and sphingomyelin (SM)) differed between the groups. Compared to the healthy subjects, 32 lipid-species differed in COPD, and 6 species differed in asthma (Figure 1). 21 species differed between asthma and COPD. <bold>Conclusion:</bold> Phospholipid composition in small airway surfactant may contribute to distinguish asthma and COPD. <fig><object-id>erj;64/suppl_68/PA2661/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> Reference 1. Almstrand AC et al. Airway monitoring by collection and mass spectrometric analysis of exhaled particles. Anal Chem. 2009;81:662-8.