title: Regulation of endotoxin-induced IL-6 production in liver sinusoidal endothelial cells and Kupffer cells by IL-10.
abstract: Sinusoidal endothelial cells and Kupffer cells are the first cell populations in the liver that come into contact with gut-derived endotoxin in portal blood. Although endotoxin concentrations as high as 1 ng/ml are physiologically present in portal blood, no local inflammation is seen. We show that the proinflammatory cytokine IL-6, which is central to the development of inflammatory reactions in the liver, is produced by sinusoidal endothelial cells and Kupffer cells in response to low concentrations of endotoxin (100 pg/ml to 1 ng/ml). The anti-inflammatory cytokine IL-10 down-regulated endotoxin-induced IL-6 release in endothelial and Kupffer cells. Importantly, Kupffer cells secreted IL-10 after endotoxin stimulation and may therefore participate in the local regulation of inflammation. We have found that IL-6 secretion in Kupffer cells is tightly regulated by endogenous IL-10, because increased IL-6 secretion resulted when neutralizing antibodies to IL- 10 were added to resting and endotoxin-challenged Kupffer cells. Furthermore, repeated exposure of endothelial cells to endotoxin induced a state of tolerance which resulted in decreased release of IL-6 in response to a second endotoxin challenge. Our results support the notion that inflammatory reactions in the liver in response to endotoxin are down-regulated by local release of the anti-inflammatory cytokine IL-10 that is produced by Kupffer cells.
authors.affiliation: I. Medizinische Klinik und Poliklinik, Universität Mainz, Germany.
authors.forename: P A
authors.initials: PA
authors.lastname: Knolle
authors.forename: E
authors.initials: E
authors.lastname: Löser
authors.forename: U
authors.initials: U
authors.lastname: Protzer
authors.forename: R
authors.initials: R
authors.lastname: Duchmann
authors.forename: E
authors.initials: E
authors.lastname: Schmitt
authors.forename: K H
authors.initials: KH
authors.lastname: zum Büschenfelde
authors.forename: S
authors.initials: S
authors.lastname: Rose-John
authors.forename: G
authors.initials: G
authors.lastname: Gerken
mesh_terms: D000818:Animals; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004731:Endotoxins / Q000494:pharmacology*; D016753:Interleukin-10 / Q000378:metabolism / Q000494:pharmacology*; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000378:metabolism; D007728:Kupffer Cells / Q000187:drug effects / Q000378:metabolism*; D008099:Liver / Q000098:blood supply / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008833:Microcirculation / Q000276:immunology / Q000378:metabolism
chemical_list: D004731:Endotoxins; D015850:Interleukin-6; D016753:Interleukin-10