Fig.1.

Evaluation of intestinal permeability. Urinary excretion of orally ingested non-metabolizable sugars of different sizes provides a reliable non-invasive in vivo read-out of intestinal barrier function. The mannitol/lactulose ratio evaluates the changes in permeability in the small intestine. Changes in the colon permeability is assessed with the addition of either sucralose or chromium-labeled EDTA. At the cellular level, there are two routes for transport of molecules and ions across the epithelium of the gut: across the plasma membrane of the epithelial cells (transcellular route) and across tight junctions between epithelial cells (paracellular route). This figure was created using Servier Medical Art, licensed under the Creative Commons Attribution 3.0 Unported License.