title: Expansion of cultures of human tracheal epithelium with maintenance of differentiated structure and function.
abstract: We have developed a technique for expanding primary cultures of human tracheal epithelium while minimizing loss of differentiated structure and function. Cells were seeded at 2 x 10(4) cells/cm2 into T75 flasks and trypsinized when approximately 80% confluent. The dispersed cells were then passaged at the same plating density into further T75 flasks or seeded at 5 x 10(5) cells/cm2 on porous-bottomed inserts and maintained with an air-interface. Differentiation of cells on inserts was assessed from transepithelial electrical resistance (an index of tight junction formation), short-circuit current (an index of transepithelial salt transport), cell numbers, total cell protein, and histology. Unpassaged cells (P0) and cells passaged once (P1) took about a week to become 80% confluent on T75 flasks, with 10-fold and 5-fold increases in cell numbers, respectively. Confluence was achieved in approximately 3 days following plating to inserts. Functionally and structurally, P1 and P2 cells (cells passaged twice) were little different from P0 cells. Thus, within a little over 2 weeks, the numbers of confluent cell sheets can be increased 50-fold with minimal change in function. However, there was a marked decline in differentiation by cells passaged three times (P3), and not all cell preparations could be taken to P4 (cells passaged four times).
authors.affiliation: Department of Human Physiology, University of California-Davis, Davis, CA 95616-8664, USA. jhwiddicombe@ucdavis.edu
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Widdicombe
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Sachs
authors.forename: Joby L
authors.initials: JL
authors.lastname: Morrow
authors.forename: Walter E
authors.initials: WE
authors.lastname: Finkbeiner
mesh_terms: D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D017097:Electric Impedance; D004847:Epithelial Cells / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D020545:Respiratory Mucosa / Q000166:cytology* / Q000502:physiology*; D014132:Trachea / Q000166:cytology* / Q000502:physiology*