Hypoxia‐induced cystic fibrosis transmembrane conductance regulator dysfunction is a universal mechanism underlying reduced mucociliary transport in sinusitis

Introduction Hypoxia due to sinus obstruction is a major pathogenic mechanism leading to sinusitis. The objective of the current study is to define the electrophysiologic characteristics of hypoxia in vitro and in vivo. Methods Cystic fibrosis bronchoepithelial cells expressing wild‐type cystic fibrosis transmembrane conductance regulator (CFTR) and human sinonasal epithelial cells were exposed to 1% or atmospheric O2 for 24 h. Time‐dependent production of cytoplasmic free radicals was measured. Cells were subjected to Ussing chamber and patch clamp technique where CFTR currents were recorded in whole‐cell and cell‐attached mode for single channel studies. Indices of mucociliary transport (MCT) were measured using micro‐optical coherence tomography. In a rabbit hypoxic maxillary sinus model, tissue oxygenation, relative mRNA expression of HIF‐1α, pH, sinus potential difference (SPD), and MCT were determined. Results Ussing chamber (p