Ion transport by cultures of human tracheobronchial submucosal glands

Acini of human tracheobronchial submucosal glands were isolated by enzymatic disaggregation, and, when plated on flasks coated with human placental collagen (HPC) in media containing Ultroser G serum substitute (USG) and a variety of growth factors (GF), they became confluent after 14-20 days. The cells were then isolated by trysinization and replated in media containing USG and GF at 10⁶ cells/cm² on porous-bottomed inserts coated with HPC. Confluent monolayers formed on day 1 after replating and were studied on day 10. Transepithelial resistance and short-circuit current (I(sc)) were 578 ± 89 Ω · cm² and 12.9 ± 1.9 μA/cm² (means ± SE, n = 23 cell sheets). The potency sequence for stimulation of I(sc) by mediators was methacholine > bradykinin > isoproterenol ≃ phenylephrine. Amiloride decreased baseline I(sc) by 42 ± 9% (n = 6 cell sheets) but had little effect on the I(sc) response to mediators. Diphenylamine-2-carboxylic acid, however, had no effect on baseline I(sc) but markedly inhibited the I(sc) response to all mediators. These results show that submucosal gland cells from human trachea can be grown in culture to produce epithelial sheets of high resistance, which secrete Cl in response to bradykinin and α- and β-adrenergic and cholinergic agents.