Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines.
Level 5 - mechanism / opinion, no new human data
Mechanistic laboratory study using cell culture models and ex vivo human intestinal biopsies
PubMed 16635908 · doi:10.1080/00365520500235334
What was done
The authors investigated the effect of gliadin exposure on zonulin release, signaling, and epithelial paracellular permeability. The study utilized in vitro intestinal cell monolayers (IEC6 and Caco2) and ex vivo human small intestinal biopsy tissues from celiac disease patients in remission and non-celiac controls. Measurements included zonulin secretion and binding, paracellular permeability in the presence or absence of the zonulin antagonist FZI/0, immunofluorescence microscopy for cytoskeletal rearrangement and zonula occludens-1 (ZO-1) redistribution, and real-time PCR for ZO-1 and occludin gene expression.
What was found
In IEC6 and Caco2 cell lines, gliadin triggered zonulin release into the culture medium, subsequent surface binding, cytoskeletal rearrangement, loss of occludin-ZO-1 interaction, and increased monolayer permeability; these structural and barrier alterations were blocked by FZI/0 without altering zonulin secretion. In ex vivo human intestinal biopsies from celiac patients in remission, gliadin induced sustained zonulin release and increased permeability, both reversed by FZI/0. In non-celiac human biopsies, gliadin induced a transient, limited zonulin release and an increase in permeability that was smaller than in celiac tissue. Chronic gliadin exposure down-regulated ZO-1 and occludin gene expression. The abstract reported no numerical values or statistical metrics.
Why it matters
This study outlines a mechanistic pathway through which gliadin directly triggers zonulin signaling to increase intestinal permeability, showing that while transient permeability increases occur in non-celiac mucosa, the response is pronounced and sustained in celiac disease.
Limits
Findings are limited to cell lines and ex vivo human tissue preparations, lacking in vivo physiological and clinical validation. The abstract reports no sample sizes for the human biopsy donors, no quantitative data, no effect sizes, and no statistical measures.
Cited by
- supports Gluten consumption has an impact on intestinal permeability (leaky gut).