Morphology of bronchial epithelial spheroids. Bronchial sheets were sampled by brushings from COPD and non-COPD patients. (A) Videomicroscopy (see video online) shows bronchial epithelial sheets-derived spheroids. (B,C) Circular pseudostratified epithelium with columnar ciliated cells facing outside, and small pyramidal basal cells. Note, the presence of a central lumen. (D,E,F) Cohesive epithelial cells with close interdigitations and cilia facing outside. (G) Phenotypic and structural characteristics of spheroids were maintained up to 8 days. Micrographs are representative of spheroids obtained from COPD and non-COPD patients (n = 11). A, ×10; B, ×40,C, ×80; D, ×800; E, ×3000; F, ×5000; G, ×800. BC, basal cells; CC, ciliated cells; Cil., cilia; arrow indicates cell interdigitations.