title: Monolayers of human alveolar epithelial cells in primary culture for pulmonary absorption and transport studies.
abstract: OBJECTIVE
  To develop a cell culture model of human alveolar epithelial cells in primary culture for the in vitro study of pulmonary absorption and transport.
  
  
  METHODS
  Type II pneumocytes isolated from normal human distal lung tissue by enzyme treatment and subsequent purification were plated on fibronectin/collagen coated polyester filter inserts, and cultured using a low-serum growth medium. Characterization of the cell culture was achieved by bioelectric measurements, cell-specific lectin binding, immunohistochemical detection of cell junctions, and by assessment of transepithelial transport of dextrans of varying molecular weights.
  
  
  RESULTS
  In culture, the isolated cells spread into confluent monolayers, exhibiting peak transepithelial resistance of 2,180 +/- 62 ohms x cm2 and potential difference of 13.5 +/- 1.0 mV (n = 30-48), and developing tight junctions as well as desmosomes. As assessed by lectin-binding, the cell monolayers consisted of mainly type I cells with some interspersed type II cells, thus well mimicking the situation in vivo. The permeability of hydrophilic macromolecular FITC-dextrans across the cell monolayer was found to be inversely related to their molecular size, with Papp values ranging from 1.7 to 0.2 x 10(-8) cm/sec.
  
  
  CONCLUSIONS
  A primary cell culture model of human alveolar epithelial cells has been established, which appears to be a valuable in vitro model for pulmonary drug delivery and transport studies.
authors.affiliation: Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany.
authors.forename: K J
authors.initials: KJ
authors.lastname: Elbert
authors.forename: U F
authors.initials: UF
authors.lastname: Schäfer
authors.forename: H J
authors.initials: HJ
authors.lastname: Schäfers
authors.forename: K J
authors.initials: KJ
authors.lastname: Kim
authors.forename: V H
authors.initials: VH
authors.lastname: Lee
authors.forename: C M
authors.initials: CM
authors.lastname: Lehr
mesh_terms: D000042:Absorption; D000280:Administration, Inhalation; D001692:Biological Transport / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D003911:Dextrans / Q000493:pharmacokinetics*; D016503:Drug Delivery Systems; D004553:Electric Conductivity; D017097:Electric Impedance; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005455:Fluorescent Antibody Technique; D006801:Humans; D037102:Lectins / Q000378:metabolism / Q000494:pharmacology; D008567:Membranes, Artificial; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000378:metabolism*
chemical_list: D003911:Dextrans; D037102:Lectins; D008567:Membranes, Artificial; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate