title: In vitro assessment of epithelial electrical resistance in human esophageal and jejunal mucosae and in Caco-2 cell layers.
abstract: OBJECTIVE
  There is a need for a technique allowing studies of human mucosal specimens collected during different clinical conditions. This study elucidates if square wave pulse analysis discriminates between epithelial and transmural electrical resistance and if there is an association with transepithelial permeability of molecular probes.
  
  
  METHODS
  Mucosae from esophagus (surgical resections: n = 14; endoscopic biopsies: n = 15) and jejunum (n = 12) and Caco-2 cell monolayers were investigated in Ussing chambers. Transmural and epithelial electrical resistance were recorded by the use of standardized current pulses. Permeability was assessed using two fluorescein-labeled probes (weight 376 and 4000 Da).
  
  
  RESULTS
  Baseline epithelial electrical resistance was higher in esophageal mucosa (~280 Ω*cm(2)), than in jejunal (~10 Ω*cm(2)) and Caco-2 cells (~140 Ω*cm(2)). The subepithelial contribution to the transmural resistance was higher in jejunal preparations (+88%) and Caco-2 cells (+75%), than in esophageal (+30%). During hypoxia the subepithelial resistance was unchanged, whereas the epithelial resistance decreased significantly in jejunal mucosa and Caco-2 cells. These findings coincided with increased transepithelial probe permeability and signs of disturbed morphology. Esophageal epithelia were resistant to hypoxia. However, exposure to deoxycholic acid and trypsin abolished the esophageal epithelial resistance and increased probe permeability. Endoscopic esophageal biopsies from patients with erosive reflux disease exhibited significantly lower epithelial resistance and higher current than healthy subjects.
  
  
  CONCLUSIONS
  Square wave pulse analysis in Ussing chambers is suitable for assessment of epithelial electrical resistance that can reflect transepithelial permeability of molecular probes with known size. Moreover, the technique discriminated between healthy and reflux-diseased esophageal mucosal biopsies.
authors.affiliation: Department of Gastrosurgical Research and Education, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden. Eleonora.bjorkman@gastro.gu.se
authors.forename: Eleonora
authors.initials: E
authors.lastname: Björkman
authors.forename: Anna
authors.initials: A
authors.lastname: Casselbrant
authors.forename: Sören
authors.initials: S
authors.lastname: Lundberg
authors.forename: Lars
authors.initials: L
authors.lastname: Fändriks
mesh_terms: D000328:Adult; D000368:Aged; D018938:Caco-2 Cells / Q000473:pathology / Q000502:physiology; D003911:Dextrans / Q000493:pharmacokinetics; D017097:Electric Impedance; D004848:Epithelium / Q000378:metabolism / Q000502:physiology*; D004942:Esophagitis, Peptic / Q000503:physiopathology; D004947:Esophagus / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D005260:Female; D019793:Fluorescein / Q000493:pharmacokinetics*; D016650:Fluorescein-5-isothiocyanate / Q000493:pharmacokinetics*; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D007413:Intestinal Mucosa / Q000473:pathology / Q000502:physiology; D007583:Jejunum / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D010539:Permeability; D055815:Young Adult
chemical_list: D003911:Dextrans; D005456:Fluorescent Dyes; D016650:Fluorescein-5-isothiocyanate; D019793:Fluorescein