title: Organotypic soft-tissue co-cultures: Morphological changes in microvascular endothelial tubes after incubation with iodinated contrast media.
abstract: BACKGROUND
  Clinical complications like thrombosis or anaphylaxis have been described to go along with the intra-venous or intra-arterial injection of iodinated contrast media (CM). It has been suggested that the administration of CM affects rheological parameters and thereby causes reduced blood velocity in microvessels. In vitro studies revealed significant buckling of endothelial cells after exposure to CM reducing the lumen of vessels. The aim of this study was to test the influence of CM on three-dimensional microvascular tubules with open lumina within an organotypic soft-tissue co-culture assay in vitro. This model, which is based on the co-culture of endothelial cells and fibroblasts, allows the analysis and quantitation of different parameters of microvascular endothelial capillary structures.
  
  
  METHODS
  Human dermal fibroblasts and human dermal microvascular endothelial cells were co-cultured for 10 days. Fibroblasts were adapted to the endothelial cell medium before co-culture and allowed to proliferate as well as produce extracellular matrix. The co-cultures were exposed to three different CM, i.e., Iomeprol (Imeron 400MCT), Iodixanol (Visipaque 320) or Iohexol (Accupaque 350) for 1.5 minutes or 5.0 minutes, respectively. For this, a mixture of CM and cell culture medium in a ratio of 30% CM by volume was prepared. After fixation in methanol/acetone, the endothelial cells were immunolabeled with the endothelial marker anti-CD31 and the tubular structures were assessed morphometrically.
  
  
  RESULTS
  In the organotypic soft-tissue co-cultures with fibroblasts, the endothelial cells developed three-dimensional capillary-like structures which expanded via sprouting branches. After incubation with the different CM, the numbers of endothelial tubes (p = 0.001) and their lengths (p = 0.003) were significantly lower after the 5 minutes incubation time, when compared to the 1.5 minutes incubation time. The tubular diameters were significantly reduced after 5 minutes (p < 0.001), when compared to the 1.5 minutes incubation duration. Interestingly, Iomeprol and Iodixanol induced an elongation of the tubular branches during incubation duration of 1.5 minutes (p = 0.015). However, after 5 minutes incubation, the tubular branches were drastically shorter in the presence of Iomeprol and Iodixanol than the tubular branches of the control (p = 0.007).
  
  
  CONCLUSIONS
  All CM exerted a negative effect on the parameters of in vitro blood vessel development.
authors.affiliation: Department of Veterinary Medicine, Institute of Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kaessmeyer
authors.affiliation: Department of Veterinary Medicine, Institute of Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Sehl
authors.affiliation: Department of Veterinary Medicine, Institute of Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Khiao In
authors.affiliation: Institute for Animal Hygiene, Animal Welfare and Farm Animal Behaviour, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Hiebl
authors.affiliation: Department of Veterinary Medicine, Institute of Veterinary Epidemiology and Biostatistics, Freie Universität Berlin, Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Merle
authors.affiliation: Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Jung
authors.affiliation: Central Institute for Biomedical Technology, Biomaterials Division, University of Ulm, Ulm, Germany.
authors.forename: R P
authors.initials: RP
authors.lastname: Franke
authors.affiliation: Department of Veterinary Medicine, Institute of Veterinary Anatomy, Freie Universität Berlin, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Plendl
mesh_terms: D018929:Cell Culture Techniques; D018920:Coculture Techniques / Q000379:methods*; D003287:Contrast Media; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans
chemical_list: D003287:Contrast Media
keywords: Iodixanol; Iohexol; Iomeprol; Soft-tissue co-cultures; angiogenesis; contrast media; microvascular endothelial tubes