Proteomic Analysis of BALF in Preterm Infants at High Risk To Develop Bronchopulmonary Dysplasia

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a multi-factorial disease regarded as impaired alveolar and vascular lung development. Bronchoalveolar lavage fluid (BALF) proteome analysis in adults both in normal and pathological conditions has made an important contribution to better understand the molecular mechanisms underlying lung disorders. Proteomic approaches have been reported in few studies of acute lung injury of premature neonates suffering from respiratory distress syndrome (RDS) and subsequent development of BPD, which remains the most frequent chronic morbidity afflicting prematurely born infants. OBJECTIVE: The aim of this study was to assess and compare the proteomic profiles of BALF from premature neonates with and without BPD. DESIGN/METHODS: 14 neonates with gestational age (GA) ≤32 weeks were enrolled; they all required intubation for RDS in the first hours of life. BALF samples, according to the duration of intubation, were collected at day 1,3,5,7. In order to get more insight into the molecular mechanisms of BPD development, we compared the comprehensive two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) protein profile of BALF from 11 preterm babies that developed BPD (mean±SD GA 26±2 weeks and mean±SD birth weight (BW)875±219 g) with that of 3 babies that did not develop BPD (mean±SD GA 30±2 weeks and mean±SD BW 1427±78 g). Differentially expressed proteins, as evaluated by image analysis, were identified by mass spectrometry. RESULTS: The proteomic analysis permitted us to identify altered protein levels in the BPD groups of patients. As expected, we found that pro-inflammatory proteins were up-regulated in preterm infants compared to age-matched controls. Moreover we identified few red-ox proteins and some proteins involved in alveolar development and surfactant cleavage, which resulted to be significantly down-regulated in BPD patients. We also validated some of the identified de-regulated proteins by Western Blot analysis. CONCLUSIONS: In conclusion, this study demonstrates the potential of proteomics to study the pattern of BALF proteins in BPD patients. This preliminary data suggested that multiple markers can better describe such a complex disease