Comparison of Vectorial Ion Transport in Primary Murine Airway and human Sinonasal Air-Liquid Interface Cultures, Models for Studies of Cystic Fibrosis, and other Airway Diseases

Background The purpose of this study was to compare vectorial ion transport within murine trachea, murine nasal septa, and human sinonasal cultured epithelium. Our hypothesis is that murine septal epithelium, rather than trachea, will more closely mimic the electrophysiology properties of human sinonasal epithelium. Methods Epithelium from murine trachea, murine septa, and human sinonasal tissue were cultured at an air-liquid interface to confluence and full differentiation. A limited number of homozygous dF508 epithelia were also cultured. Monolayers were mounted in modified Ussing chambers to investigate pharmacologic manipulation of ion transport. Results The change in forskolin-stimulated current (delta-ISC, expressed as micro-A/cm2) in murine septal (n = 19; 16.84 ± 2.09) and human sinonasal (n = 18; 12.15 ± 1.93) cultures was significantly increased over murine tracheal cultures (n = 15; 6.75 ± 1.35; p = 0.035 and 0.0005, respectively). Forskolin-stimulated ISC was inhibited by the specific cystic fibrosis transmembrane regulator (CFTR) inhibitor INH-172 (5 μM). No forskolin-stimulated ISC was shown in cultures of dF508 homozygous murine septal epithelium (n = 3). Murine septal ISC was largely inhibited by amiloride (12.03 ± 0.66), whereas human sinonasal cultures had a very limited response (0.70 ± 0.47; p < 0.0001). The contribution of CFTR to stimulated chloride current as measured by INH-172 was highly significantly different between all groups (murine septa, 19.51 ± 1.28; human sinonasal, 11.12 ± 1.58; murine trachea, 4.85 ± 0.49; p < 0.0001). Conclusion Human sinonasal and murine septal epithelial cultures represent a useful model for studying CFTR activity and may provide significant advantages over lower airway tissues for investigating upper and lower respiratory pathophysiology.