Metabolic profiling in human lung injuries by high-resolution nuclear magnetic resonance spectroscopy of bronchoalveolar lavage fluid (BALF)

We present a method for identifying biomarkers in human lung injury. The method is based on high-resolution nuclear magnetic resonance (NMR) spectroscopy applied to bronchoalveolar lavage fluid (BALF) collected from lungs of critically ill patients. This biological fluid can be obtained by bronchoscopic and non-bronchoscopic methods. The type of lung injury in acute respiratory failure presenting as acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), continues to challenge critical care physicians. We characterize different metabolites in BAL fluid by non-bronchoscopic method (mBALF) for better diagnosis and understanding of ALI/ARDS by NMR spectroscopy. NMR spectra of mBALF collected from 30 patients (9 controls, 10 ARDS and 11 ALI) were analyzed for the identification of biomarkers. Statistical methods such as principal components analysis and partial least square discriminant analysis were carried out on H-1 NMR spectrum of mBALF to identify biomarker responsible for separation among different lung injuries classes (ALI and ARDS) and normal lungs. The corresponding correlation of biomarkers with metabolic cycle has given insight into metabolism of lung injuries in critically ill patients. Our study shows statistically significant differentiation of various metabolites concentration in mBALF collected from lungs of ALI, ARDS and healthy control patients, making NMR spectroscopy as a possible new method of characterizing human lung injury.