NMR spectroscopy metabolomic profiling of exhaled breath condensate in patients with stable and unstable cystic fibrosis

Abstract

Background Metabolomics could provide new insights into the pathophysiology of cystic fibrosis (CF) by identifying profiles of endogenous metabolites. Objectives To investigate whether metabolomics of exhaled breath condensate could discriminate between patients with unstable CF, stable CF and healthy subjects, and whether selected metabolites were responsible for between-group differences. Methods Twenty-nine patients with stable CF, 24 with unstable CF and 31 healthy subjects (age 9e24 years) participated in a cross-sectional study. Metabolomics was performed with high-resolution nuclear magnetic resonance spectroscopy. Partial least squaresdiscriminant analysis was used as classifier. The results were validated in a second independent study. Results Intraclass correlation coefficients for betweenday and technical repeatability were 0.93 and 0.96, respectively. BlandeAltman analysis showed good within-day repeatability. Correct classification rate of CF (n¼53) vs healthy subjects (n¼31) was 96% (R 2 ¼0.84; Q 2 ¼0.79). Model validation with a testing sample set obtained from subjects not included in the primary analysis (23 CF and 25 healthy subjects) showed a sensitivity of 91% and a specificity of 96%. The classification rate of stable CF (n¼29) vs unstable CF patients (n¼24) was 95% (R 2 ¼0.82; Q 2 ¼0.78). Model external validation in 14 patients with stable CF and 16 with unstable CF showed a sensitivity of 86% and a specificity of 94%. Ethanol, acetate, 2-propanol and acetone were most discriminant between patients with CF and healthy subjects, whereas acetate, ethanol, 2-propanol and methanol were the most important metabolites for discriminating between patients with stable and unstable CF. Conclusions Nuclear magnetic resonance spectroscopy of exhaled breath condensate is reproducible, discriminates patients with CF from healthy subjects and patients with unstable CF from those with stable CF, and identifies the metabolites responsible for between-group differences.

Exhaled breath condensate: a comprehensive update

“…Although NMR has a lower sensitivity compared to enzyme-linked immunosorbent assay (ELISA) and mass spectrometry, it is a non-destructive analytical method that requires minimal sample preparation and has rapid acquisition time of about 10 -15 min [ 104 ]. NMR-based metabolomics of EBC may have a potential use in characterising respiratory diseases as it was able to discriminate patients with COPD [ 104 ], asthma [ 106 ], stable and unstable cystic fibrosis [ 107 ] from healthy subjects. In addition, a recent NMR spectroscopic study has also shown that the repeated use of the EcoScreen ® condenser does not cause any carry-over effect and the disinfectant Milton does not alter EBC metabolomics [ 100 ], as opposed to another study that reported artificial signals when the Anacon condenser was used and disinfected with Descogen [ 108 ].…”

Developmental Regulation of Antioxidant Enzymes and Their Impact on Neonatal Lung Disease

“…Advances in electronic-nose and NMR spectroscopy technologies represent a novel option as direct quantification of pulmonary oxidative stress can be obtained from exhaled breath and monitored serially for change with clinical interventions (79,80,120). In a small study, peak exhaled pentane levels in premature infants correlated with the risk of ROP, but not BPD (87).…”

Metabolomics of Exhaled Breath Condensate: A Means for Phenotyping Respiratory Diseases?

“…Montuschi et al [19] evaluated the possibility to discriminate between patients with stable and unstable CF by NMR-based metabolomics. In their controlled and validated study, "Recently, our group characterized the respiratory metabotype of obese a sthmatic patients, and compared it to that of lean asthmatic patients.…”