Thorsten Walles

In vitro airway models are increasingly important for pathomechanistic analyses of respiratory diseases. Existing models are limited in their validity by their incomplete cellular complexity. We therefore aimed to generate a more complex and meaningful three-dimensional (3D) airway model. Primary human bronchial epithelial cells (hbEC) were propagated in airway epithelial cell growth (AECG) or PneumaCult ExPlus medium. Generating 3D models, hbEC were airlifted and cultured on a collagen matrix with donor-matched bronchial fibroblasts for 21 days comparing two media (AECG or PneumaCult ALI (PC ALI)). 3D models were characterized by histology and immunofluorescence staining. The epithelial barrier function was quantified by transepithelial electrical resistance (TEER) measurements. The presence and function of ciliated epithelium were determined by Western blot and microscopy with high-speed camera. In 2D cultures, an increased number of cytokeratin 14-positive hbEC was present with AECG medium. In 3D models, AECG medium accounted for high proliferation, resulting in hypertrophic epithelium and fluctuating TEER values. Models cultured with PC ALI medium developed a functional ciliated epithelium with a stable epithelial barrier. Here, we established a 3D model with high in vivo–in vitro correlation, which has the potential to close the translational gap for investigations of the human respiratory epithelium in pharmacological, infectiological, and inflammatory research.