title: The role of the intestinal microvasculature in inflammatory bowel disease: studies with a modified Caco-2 model including endothelial cells resembling the intestinal barrier in vitro.
abstract: The microvascular endothelium of the gut barrier plays a crucial role during inflammation in inflammatory bowel disease. We have modified a commonly used intestinal cell model based on the Caco-2 cells by adding microvascular endothelial cells (ISO-HAS-1). Transwell filters were used with intestinal barrier-forming Caco-2 cells on top and the ISO-HAS-1 on the bottom of the filter. The goal was to determine whether this coculture mimics the in vivo situation more closely, and whether the model is suitable to evaluate interactions of, for example, prospective nanosized drug vehicles or contrast agents with this coculture in a physiological and inflamed state as it would occur in inflammatory bowel disease. We monitored the inflammatory responsiveness of the cells (release of IL-8, soluble intercellular adhesion molecule 1, and soluble E-selectin) after exposure to inflammatory stimuli (lipopolysaccharide, TNF-α, INF-γ, IL1-β) and a nanoparticle (Ba/Gd: coprecipitated BaSO4and Gd(OH)3), generally used as contrast agents. The barrier integrity of the coculture was evaluated via the determination of transepithelial electrical resistance and the apparent permeability coefficient (Papp) of NaFITC. The behavior of the coculture Caco-1/ISO-HAS-1 was compared to the respective monocultures Caco-2 and ISO-HAS-1. Based on transepithelial electrical resistance, the epithelial barrier integrity of the coculture remained stable during incubation with all stimuli, whereas the Pappdecreased after exposure to the cytokine mixture (TNF-α, INF-γ, IL1-β, and Ba/Gd). Both the endothelial and epithelial monocultures showed a high inflammatory response in both the upper and lower transwell-compartments. However, in the coculture, inflammatory mediators were only detected on the epithelial side and not on the endothelial side. Thus in the coculture, based on the Papp, the epithelial barrier appears to prevent a potential inflammatory overreaction in the underlying endothelial cells. In summary, this coculture model exhibits in vivo-like features, which cannot be observed in conventional monocultures, making the former more suitable to study interactions with external stimuli.
authors.affiliation: Institute of Pathology, University Medical Center, Mainz.
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Kasper
authors.affiliation: Institute of Pathology, University Medical Center, Mainz.
authors.forename: Maria Iris
authors.initials: MI
authors.lastname: Hermanns
authors.affiliation: Leibniz Institute for New Materials.
authors.forename: Christian
authors.initials: C
authors.lastname: Cavelius
authors.affiliation: Leibniz Institute for New Materials.
authors.forename: Annette
authors.initials: A
authors.lastname: Kraegeloh
authors.affiliation: NanoGate AG, Goettelborn, Saarbrücken, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jung
authors.affiliation: NanoGate AG, Goettelborn, Saarbrücken, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Danzebrink
authors.affiliation: Institute of Pathology, University Medical Center, Mainz.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Unger
authors.affiliation: Institute of Pathology, University Medical Center, Mainz.
authors.forename: Charles James
authors.initials: CJ
authors.lastname: Kirkpatrick
mesh_terms: D018938:Caco-2 Cells; D018920:Coculture Techniques; D016207:Cytokines / Q000378:metabolism*; D017097:Electric Impedance; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D018836:Inflammation Mediators / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D055806:Microvessels
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D008070:Lipopolysaccharides
keywords: Caco-2; ISO-HAS-1; inflammatory bowel disease; intestinal barrier in vitro; intestinal microvasculature; nanosized gadolinium contrast agent; sICAM-1; soluble E-selectin