title: Evaluation of oesophageal mucosa integrity by the intraluminal impedance technique.
abstract: BACKGROUND
  Oesophageal intraluminal impedance is currently used for assessment of reflux in gastro-oesophageal reflux disease (GORD). Oesophageal mucosa integrity may have a key role in heartburn perception in non-erosive reflux disease (NERD). Severe erosive oesophagitis is associated with low impedance baseline. We hypothesised that impedance baseline measurements could be used to evaluate changes in oesophageal mucosa integrity in man.
  
  
  METHODS
  We measured oesophageal impedance baseline before, during and after acid perfusion in rabbits and healthy subjects. Transepithelial resistance (TER) was determined and dilated intercellular spaces (DIS) were assessed in isolated rabbit oesophageal mucosa. Impedance baseline was measured retrospectively at different levels of the oesophagus in impedance-pH recordings from asymptomatic volunteers and patients with GORD.
  
  
  RESULTS
  In healthy subjects and rabbits, impedance baseline dropped dramatically during perfusion of control solution (pH 7.2) but after perfusion, impedance recovered. In rabbits, after perfusion with saline pH 1.5 and 1.0 impedance values remained a 39.1 ± 7.0% and 63.9 ± 6.5% (p < 0.05) lower respectively. There was a positive correlation between in vivo basal impedance and in vitro TER values (r = 0.72, p = 0.0021). Tissue showed no erosions but both acidic solutions induced DIS. In healthy subjects, after perfusion with saline pH 2.0 and 1.0 the impedance baseline remained lower a 21.9 ± 6.5% and 52.7 ± 5.0%, (p < 0.0001) respectively. Patients with GORD have a lower impedance baseline than healthy volunteers at the distal oesophagus.
  
  
  CONCLUSIONS
  Impedance baseline measurements might be used to evaluate the status of the oesophageal mucosa and to study the role of the impaired mucosal integrity in acid-induced heartburn in healthy volunteers and in patients with GORD.
authors.affiliation: Translational Research Center for Gastrointestinal Disorders, Gasthuisberg, Leuven 3000, Belgium. ricard.farre@med.kuleuven.be
authors.forename: Ricard
authors.initials: R
authors.lastname: Farré
authors.forename: Kathleen
authors.initials: K
authors.lastname: Blondeau
authors.forename: Dominique
authors.initials: D
authors.lastname: Clement
authors.forename: Maria
authors.initials: M
authors.lastname: Vicario
authors.forename: Lucia
authors.initials: L
authors.lastname: Cardozo
authors.forename: Michael
authors.initials: M
authors.lastname: Vieth
authors.forename: Veerle
authors.initials: V
authors.lastname: Mertens
authors.forename: Ans
authors.initials: A
authors.lastname: Pauwels
authors.forename: Jiri
authors.initials: J
authors.lastname: Silny
authors.forename: Marcel
authors.initials: M
authors.lastname: Jimenez
authors.forename: Jan
authors.initials: J
authors.lastname: Tack
authors.forename: Daniel
authors.initials: D
authors.lastname: Sifrim
mesh_terms: D000328:Adult; D000818:Animals; D017097:Electric Impedance; D004947:Esophagus / Q000503:physiopathology* / Q000648:ultrastructure; D005110:Extracellular Space / Q000502:physiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008854:Microscopy, Electron; D009092:Mucous Membrane / Q000503:physiopathology / Q000648:ultrastructure; D011817:Rabbits; D012189:Retrospective Studies; D055815:Young Adult