The integrated analysis of changes in the metabolic profile could be critical for the discovery of biomarkers of lung injury, and also for generating new pathophysiological hypotheses and designing novel therapeutic targets for the acute respiratory distress syndrome (ARDS). This study aimed at developing a nuclear magnetic resonance (NMR)-based approach for the identification of the metabolomic profile of ARDS in patients with H1N1 influenza virus pneumonia.
Serum samples from 30 patients (derivation set) diagnosed of H1N1 influenza virus pneumonia were analyzed by unsupervised principal component analysis to identify metabolic differences between patients with and without ARDS by NMR spectroscopy. A predictive model of partial least squares discriminant analysis (PLS-DA) was developed for the identification of ARDS. PLS-DA was trained with the derivation set and tested in another set of samples from 26 patients also diagnosed of H1N1 influenza virus pneumonia (validation set).
Decreased serum glucose, alanine, glutamine, methylhistidine and fatty acids concentrations, and elevated serum phenylalanine and methylguanidine concentrations, discriminated patients with ARDS versus patients without ARDS. PLS-DA model successfully identified the presence of ARDS in the validation set with a success rate of 92% (sensitivity 100% and specificity 91%). The classification functions showed a good correlation with the Sequential Organ Failure Assessment score (R = 0.74, P < 0.0001) and the PaO2/FiO2 ratio (R = 0.41, P = 0.03).
The serum metabolomic profile is sensitive and specific to identify ARDS in patients with H1N1 influenza A pneumonia. Future studies are needed to determine the role of NMR spectroscopy as a biomarker of ARDS.
*CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
†Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
‡Department of Critical Care, Hospital Universitario de Getafe, Madrid, Spain
§Hospital del Mar Medical Research Institute (IMIM), Hospital Universitario del Mar, Barcelona, Spain
||School of Pharmacy, Universidad Complutense de Madrid, Madrid, Spain
¶Universidad Europea, Madrid, Spain
Address reprint requests to Jose A. Lorente, Department of Critical Care, Hospital Universitario de Getafe, 28905 Madrid, Spain. E-mail: email@example.com
Received 13 September, 2017
Revised 29 September, 2017
Accepted 21 December, 2017
JLI-G and NN contributed equally to the manuscript.
This research was supported by the Spanish Ministry of Economy, Industry and Competitiveness (MEIC-AEI) grants SAF2016-79593P and SAF2014-59118-JIN, by European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement ITN-FP7-608027 and by European Union Funding ERDF (FIS 15/01942). JLI-G is a CNIC IPP COFUND Fellow and has received funding from the People Programme (Marie Curie Actions) of the FP7/2007-2013 under REA grant agreement no 600396. The CNIC is supported by MEIC-AEI and the Pro CNIC Foundation, and is a Severo Ochoa Centre of Excellence (MEIC award SEV-2015-0505).
The authors report no conflicts of interest.