1H NMR to Explore the Metabolome of Exhaled Breath Condensate in α1-Antitrypsin Deficient Patients: A Pilot Study

The metabolomic analysis of exhaled breath condensate (EBC) may provide insights on both the pathology of pulmonary disorders and the response to therapy. This pilot study describes the ability of nuclear magnetic resonance (NMR)-based metabolomics to discriminate α1-antitrypsin deficient (AATD)-patients, who were diagnosed with moderate to severe emphysema, from healthy individuals. Comparative analysis of samples from these two homogeneous cohorts of individuals resulted in the generation of NMR profiles that were different from both a qualitative and a quantitative point-of-view. Among the identified metabolites that separated patients from controls, acetoin, propionate, acetate, and propane-1,2 diol were those presenting the biggest difference. Unambiguous confirmation that the two groups could be completely differentiated on the basis of their metabolite content came from the application of univariate and multivariate statistical analysis (principal component analysis, partial least squares discriminant analysis (PLS-DA), and orthogonal PLS-DA). MetaboAnalyst 3.0 platform, used to define a relationship among metabolites, allowed us to observe that pyruvate metabolism is the most-involved pathway, most of metabolites being originated from pyruvate. These preliminary data suggest that NMR, with its ability to differentiate the metabolic fingerprint of EBC of AATD patients from that of healthy controls, has a potential "clinical applicability" in this area.