title: Intestinal permeability in humans is increased after radiation therapy.
abstract: OBJECTIVE
  Irradiation inflicts acute injuries to the intestinal mucosa with rapid apoptosis induction and subsequent reduction in epithelial surface area. It may therefore be assumed that the intestinal barrier function is affected. The aim of this study was to compare the mucosal permeability in irradiated rectum and nonirradiated sigmoid colon from patients subjected to radiation therapy before surgical treatment for rectal cancer.
  
  
  METHODS
  Segments from sigmoid colon and rectum obtained from irradiated and nonirradiated patients were stripped from the serosa-muscle layer and mounted in Ussing diffusion chambers. The mucosa-to-serosa passage of the marker molecules 14C-mannitol, fluorescein isothiocyanate-dextran 4,400, and ovalbumin was followed for 120 minutes.
  
  
  RESULTS
  The permeability to the markers was size-dependent and increased linearly across time in all specimens. The passage of all markers was increased in irradiated rectum compared with nonirradiated sigmoid colon, whereas in specimens from nonirradiated patients there were no differences between rectum and sigmoid colon. Histologic signs of crypt and mucosal atrophy were found in the irradiated rectal specimens.
  
  
  CONCLUSIONS
  Early gastrointestinal complications after radiation therapy may be the result of mucosal atrophy in addition to mucosal damage, with a loss of barrier integrity.
authors.affiliation: Department of Animal Physiology, Lund, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Nejdfors
authors.forename: M
authors.initials: M
authors.lastname: Ekelund
authors.forename: B R
authors.initials: BR
authors.lastname: Weström
authors.forename: R
authors.initials: R
authors.lastname: Willén
authors.forename: B
authors.initials: B
authors.lastname: Jeppsson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D012809:Colon, Sigmoid / Q000166:cytology / Q000378:metabolism; D003911:Dextrans / Q000493:pharmacokinetics*; D004234:Diuretics, Osmotic / Q000493:pharmacokinetics; D005260:Female; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000528:radiation effects; D008297:Male; D008353:Mannitol / Q000493:pharmacokinetics*; D008875:Middle Aged; D010047:Ovalbumin / Q000493:pharmacokinetics*; D010539:Permeability / Q000528:radiation effects; D012004:Rectal Neoplasms / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D012007:Rectum / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects
chemical_list: D002250:Carbon Radioisotopes; D003911:Dextrans; D004234:Diuretics, Osmotic; C015219:fluorescein isothiocyanate dextran; D008353:Mannitol; D010047:Ovalbumin; D016650:Fluorescein-5-isothiocyanate