Regulation of tight-junction permeability during nutrient absorption across the intestinal epithelium.
Level 5 - mechanism / opinion, no new human data
Narrative review of physiological mechanisms and theoretical models without systematic search or primary empirical data.
PubMed 8527224 · doi:10.1146/annurev.nu.15.070195.000343
What was done
This narrative review summarizes the physiological basis and regulation of intestinal epithelial tight-junction permeability during nutrient absorption. It details the molecular architecture of tight junctions, cytoskeletal interactions, and physical and chemical regulatory forces, specifically evaluating the Pappenheimer hypothesis regarding paracellular versus transcellular glucose absorption.
What was found
The abstract reports no quantitative values or statistical metrics. It describes that tight-junction permeability is actively modulated by nutrient absorption and outlines the conditions required for substantial paracellular glucose flux under the Pappenheimer model: increased junctional permeability, very high intraluminal glucose concentrations, and adequate osmotic gradients to drive volume flow.
Why it matters
It clarifies the structural and dynamic mechanisms of epithelial barrier regulation during digestion, framing the physiological debate on the relative contributions of paracellular diffusion versus active transcellular transport in glucose uptake.
Limits
As a narrative review, it lacks a systematic literature search, formal inclusion criteria, and meta-analytic synthesis. The abstract provides no primary data, sample sizes, or quantitative effect estimates.
Cited by
- supports Intestinal epithelial tight junctions transiently open and close during normal meal consumption.