title: Increased bacterial translocation in gluten-sensitive mice is independent of small intestinal paracellular permeability defect.
abstract: OBJECTIVE
  We investigated whether treatment with gliadin induces a paracellular permeability defect that enhances bacterial translocation to mesenteric lymph nodes (MLN) via resident dendritic cells (DC) expressing TLR-2 or 4 in HCD4/HLA-DQ8 transgenic mice.
  
  
  METHODS
  HLA-DQ8 transgenic mice were sensitized and subsequently gavaged with gliadin, in the presence or absence of AT1001 (paracellular permeability inhibitor). Non-sensitized mice were gavaged with indomethacin (permeability inducer) or rice cereal. CD11c and CD103 (DC markers) and TLR-2 and 4 were investigated by immunostaining. Intestinal permeability was assessed by paracellular flux of (51)Cr-EDTA in Ussing chambers. Bacterial translocation to MLN was performed by plate counting on aerobic and anaerobic conditions.
  
  
  RESULTS
  In gliadin-treated mice, both (51)Cr-EDTA flux in jejunal mucosa and aerobic and anaerobic bacterial counts in MLN were increased (p < 0.05) compared to indomethacin-treated mice and controls. The inhibitor AT1001 normalized (51)Cr-EDTA flux, but had no effect on bacterial translocation in gliadin-treated mice. In addition, changes in mucosal DC marker distribution such as increased (p < 0.05) trans-epithelial CD103(+) cells and reduction (p < 0.05) of CD11c immunostaining were detected in gliadin-treated mice. Moreover, changes in DC markers and TLR-2 or 4 immunophenotypes were not associated.
  
  
  CONCLUSIONS
  Pharmacological restoration of paracellular permeability was not sufficient to prevent bacterial translocation in gluten-sensitive mice. We hypothesize that transcellular mechanisms involving CD103(+)DC and CD11c(+)DC may explain in gluten-sensitive HCD4/HLA-DQ8 transgenic mice the sustained increased bacterial translocation observed in the absence of a significant inflammatory response.
authors.affiliation: Department of Medicine, Health Sciences Centre, Farncombe Family Digestive Health Research Institute, McMaster University, 1200 Main Street West, Hamilton, ON L8N 3Z5, Canada. msilvamu@hotmail.com
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Silva
authors.forename: Jennifer
authors.initials: J
authors.lastname: Jury
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Sanz
authors.forename: Michelle
authors.initials: M
authors.lastname: Wiepjes
authors.forename: Xianxi
authors.initials: X
authors.lastname: Huang
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Murray
authors.forename: Chella S
authors.initials: CS
authors.lastname: David
authors.forename: Alessio
authors.initials: A
authors.lastname: Fasano
authors.forename: Elena F
authors.initials: EF
authors.lastname: Verdú
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D018988:Bacterial Translocation / Q000502:physiology*; D039521:CD11c Antigen / Q000378:metabolism; D002446:Celiac Disease / Q000139:chemically induced* / Q000503:physiopathology*; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology*; D003713:Dendritic Cells / Q000378:metabolism / Q000382:microbiology; D004195:Disease Models, Animal; D005903:Gliadin / Q000009:adverse effects* / Q000494:pharmacology; D006683:HLA-DQ Antigens / Q000235:genetics; D039001:Integrin alpha Chains / Q000378:metabolism; D007421:Intestine, Small / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D008198:Lymph Nodes / Q000382:microbiology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009842:Oligopeptides / Q000494:pharmacology; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D039521:CD11c Antigen; D006683:HLA-DQ Antigens; C109756:HLA-DQ8 antigen; D039001:Integrin alpha Chains; D009842:Oligopeptides; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; C091367:alpha E integrins; D005903:Gliadin; C525167:larazotide acetate