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Maintenance of normal, metaplastic, and dysplastic states of adult human bronchial mucosa in organ culture.

Summary Bronchial mucosa was obtained from 10 patients undergoing lobectomy (8 for squamous bronchogenic carcinoma) and from 13 patients examined by bronchoscopy. Randomly chosen mucosal patches were incubated with tritiated thymidine and fixed as fresh samples, while others were labeled and fixed after 5 to 15 days of maintenance in organ culture. Histological and autoradiographic observations indicated that some mucosal patches bore epithelia with more than one histological state. Of 43 fresh mucosal samples, 26 had viable epithelium, in which 29 histological states were identified. Five were pathological, with squamous metaplasia in two instances and with localized dysplasia sufficiently marked to be considered as possible carcinoma in situ in three instances. Of 133 cultured explants, 106 bore viable epithelium in which 110 histological states were identified. When initially present, columnar epithelium was retained in about 70% of explants; this retention occurred more often if explants were from whole bronchi rather than from biopsies. Nine cultured explants bore dysplastic or squamous metaplastic epithelium; these were from patients yielding such lesions in fresh samples. Dysplasias were as highly cellular and replicative after maintenance in culture as they were before incubation, suggesting continuity of replication among pleomorphic cells, consistent with potentially preneoplastic lesions. Squamous metaplasias were poorly sustained. Swelling and sloughing of abnormal cells were consistent with failure of the system to sustain this abnormal state or with early phases in the reversal of squamous metaplasia in organ culture.