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Updated: Jul 11, 2026
06:04
Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease
Published on: February 9, 2016
Epithelial barrier function in vivo is sustained despite gaps in epithelial layers
Alastair J M Watson1, Shaoyou Chu, Leah Sieck
1Department of Medicine, University of Liverpool, Liverpool, United Kingdom.
Gastroenterology
|September 7, 2005
Summary
Small intestinal epithelial cells shed, but barrier function is maintained by an impermeable substance filling gaps. This barrier is sustained at the apical pole, even with cell layer discontinuities.
Area of Science:
- Gastroenterology
- Cell Biology
- Epithelial Biology
Background:
- Small intestinal epithelial cells undergo high turnover, migrating to villus tips and shedding.
- Mechanisms maintaining intestinal barrier integrity during rapid cell turnover are poorly understood.
Purpose of the Study:
- Investigate epithelial shedding mechanisms in the small intestine.
- Determine the location of the permeability barrier during cell shedding using high-resolution in vivo microscopy.
Main Methods:
- High-resolution in vivo multiphoton microscopy of mouse small intestine.
- Staining of nuclei, cytosol, and cell membranes with specific dyes.
- Detection of apoptosis using a fluorescent caspase substrate (PhiPhiLux).
Main Results:
- Gaps lacking cellular components were observed in the epithelial monolayer, filled with an impermeable substance.
- Impermeable substance completely occluded gaps left by shed cells.
- Cell shedding preceded detectable caspase activation or nuclear condensation; barrier function was sustained apically.
Conclusions:
- Epithelial barrier integrity in the small intestine is maintained apically.
- Barrier function persists despite discontinuities in the cellular layer during high cell turnover.
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