AN IN VITRO MODEL OF FULL-THICKNESS HUMAN AIRWAY EPITHELIUM (EPIAIRWAY-FT) FOR STUDY OF EPITHELIUM/MATRIX INTERACTIONS.

In vitro models of airway epithelium (AE) have potential utility for study of diseases such as asthma and COPD, development of inhalable therapeutics, and toxicology of hazardous chemicals. However, degradation and remodeling of subepithelial stromal tissue are important aspects of many airway disease states, and are strongly influenced by fibroblasts (FB) residing in stromal tissue. To allow in vitro study of epithelium/matrix/FB interactions, a highly differentiated full thickness model composed of FB-containing collagen matrix and AE cells was therefore developed. Normal human pulmonary FB were cultured within a collagen matrix supported by a microporous membrane. Normal human tracheal/bronchial epithelial cells were then cultured above the matrix. The tissue constructs were induced to differentiate to an in vivo-like mucociliary phenotype by raising to the air/liquid interface. Histologic examination of the AE equivalent shows a collagen matrix populated by numerous viable FB and a pseudostratified epithelium with mucociliary morphology typical of in vivo airway epithelium. The ultrastructure of the AE equivalent was also examined by transmission electron microscopy. Fully developed cilia were observed at the apical surface. Hemidesmosomes were aligned along the plasma membranes of the basal cells. Well-defined, continuous lamina lucida and lamina densa and fine anchoring filaments were present beneath the basal epithelial cells. Anchoring fibrils connected the lamina densa to the underlying collagen matrix. EpiAirway-FT™ overcomes shortcomings of previous models in terms of providing epithelial cell/FB/matrix interactions as well as appropriate in vivo-like morphology and basement membrane development. These attributes will enable more realistic in vitro studies of airway epithelium phenomena.

Airway epithelium (AE), Asthma, Basal cells, Basal epithelial cells, Basement membrane, Bronchial epithelial cells, COPD, Collagen matrix, EpiAirway, EpiAirway-FT, Epithelium, Fibroblasts (FB), Full thickness model, In vitro, In vivo , Lamina densa, Lamina lucida, Matrix, Microporous membrane, Mucociliary morphology, Mucociliary phenotype, Plasma membrane, Pseudostratified epithelium, Pulmonary FB, Tracheal epithelial cells, Transmission electron microscopy