Bronchoalveolar pepsin, bile acids, oxidation, and inflammation in children with Gastroesophageal reflux disease

Introduction: Gastroesophageal reflux has been suggested as an underlying cause of chronic lung disease. The aim of this study was to assess the value of pepsin and bile acids, both components of GI secretions, in the lungs of children with chronic lung diseases as possible markers for gastroesophageal reflux disease and their relation to oxidation and inflammation. Materials and methods: BAL was performed in 96 children with different chronic lung diseases. Gastroesophageal reflux was analyzed by two-channel, 24-h esophageal pH measurements. Lung pepsin and bile acids were measured in BAL enzymatically, interleukin (IL)-8 by enzyme-linked immunosorbent assay, and protein carbonyls by slot blot immunoassay. Results: Sixty-five of the 96 children (68%) had an extensive proximal acidic reflux index. Children with reflux had higher pepsin concentrations in their BAL fluid (BALF), compared to children without reflux despite low specificity. No differences were observed for bile acids. Percentages of neutrophils, levels of protein carbonyls, and levels of IL-8 in BALF correlated with the number of proximal reflux events. Conclusions: Pulmonary microaspiration as demonstrated by pepsin detection in BALF is common in children with chronic lung diseases, suggesting that gastroesophageal reflux may contribute significantly to the disease pathogenesis. BALF pepsin concentration correlates positively with the number of proximal reflux events. Protein oxidation in BALF is higher in children with extensive proximal acidic reflux, suggesting that pulmonary microaspirations contribute to lung damage.