title: Barrier effects of nutritional factors.
abstract: High dietary intake of fruits and vegetables is associated with a reduced disease risk. Therefore, clinical interest is growing in therapies based on dietary supplements and effects of food components. Immune-modulatory and barrier-protective effects have been described for the amino acid glutamine and the trace element zinc. In Caco-2-cells, zinc is necessary to maintain the expression of proteins like ZO-1 and occludin, and experimental evidence exists that glutamine has enterocyte-protective effects and modulates intestinal barrier function in stressed animals and humans. Polyunsaturated fatty acids (PUFA) improve paracellular permeability after IL-4 incubation. Enhancement of barrier properties by long-chain PUFA is discussed controversially, but a beneficial role preventing the redistribution of occludin and ZO-1 and reduction of epithelial resistance by IFN-gamma and TNF-alpha exists. In addition, a group of secondary plant compounds, the polyphenols, are supposed to be important in this respect. The flavonoid quercetin and its metabolite DHBA increased epithelial resistance of Caco-2-cells to 157 +/- 4% of control values, and DHBA up to 119 +/- 4% of control values, respectively. This is due to a 2.3 +/- 0.1-fold expression rate of the tight junction protein claudin-4.
authors.affiliation: Department of Gastroenterology,Charité, Campus Benjamin Franklin, Berlin, Germany. maren.amasheh@charite.de
authors.forename: Maren
authors.initials: M
authors.lastname: Amasheh
authors.forename: Susanne
authors.initials: S
authors.lastname: Andres
authors.forename: Salah
authors.initials: S
authors.lastname: Amasheh
authors.forename: Michael
authors.initials: M
authors.lastname: Fromm
authors.forename: Jörg-Dieter
authors.initials: JD
authors.lastname: Schulzke
mesh_terms: D018938:Caco-2 Cells; D002463:Cell Membrane Permeability; D062506:Claudin-4; D017097:Electric Impedance; D004847:Epithelial Cells / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology*; D005973:Glutamine / Q000494:pharmacology*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism*; D062793:Occludin; D010636:Phenols / Q000494:pharmacology*; D059808:Polyphenols; D011794:Quercetin / Q000378:metabolism / Q000494:pharmacology; D019108:Tight Junctions / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C568157:CLDN4 protein, human; D062506:Claudin-4; D005231:Fatty Acids, Unsaturated; D005419:Flavonoids; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010636:Phenols; D059808:Polyphenols; D014409:Tumor Necrosis Factor-alpha; D005973:Glutamine; D015847:Interleukin-4; D007371:Interferon-gamma; D011794:Quercetin