Exhaled breath condensate as a potential biomarker tool for idiopathic pulmonary fibrosis - a pilot study.

Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease with poor survival. There is an urgent need to better diagnose and monitor IPF patients as new treatments are now available which slow down disease progression. Exhaled breath condensate (EBC) is easily and non-invasively collected, but analysis of potential biomarkers is difficult due to low concentrations and methodological limitations. We now used a non-targeted metabolomics approach to identify further discriminatory metabolic profiles that distinguish IPF patients from controls.
 We collected EBC from 10 stable IPF patients and 10 lung healthy controls. Samples were analyzed by ultra high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) in positive and negative ion mode. An in-house established bioinformatics pipeline was applied for data processing and analysis. In total 31 metabolites were found to be discriminative between IPF patients and controls. By univariate statistics of both datasets, 8 metabolic features remained significant (standardized abundance, FDR p-value < 0.05). Of them, all were detected in positive ion mode. Changes up to 3-fold were observed and all candidates were down-regulated in IPF patients compared to controls. Even though a discriminative metabolite signature was found between IPF patients and controls, the identities of the individual metabolites still remain elusive.
 Our preliminary results identified a distinguished EBC profile of IPF patients compared to controls. Although these results need to be confirmed in additional individuals, EBC sampling as a method to diagnose and/or monitor IPF patients is a promising, exciting new method, which deserves further exploration.
 The EBC samples have been obtained within the clinical trial NCT02173145 at baseline