Keynote review: epithelial and endothelial barriers in human disease.

There is a spectrum of distinct disease states that have in common their effect of breaking down epithelial and/or endothelial barrier function. Fluid compartmentalization goes awry, with profound implications for epithelial and stromal homeostasis, fluid and/or electrolyte balance, generation of inflammatory states, and even tumor microenvironment. Specific effects on the tight junction are found to be integral to bacterial invasion and tumor progression.