@article{SchwabMeeuwsenEhlickeetal.2017,
  author    = {Schwab, Andrea and Meeuwsen, Annick and Ehlicke, Franziska and Hansmann, Jan and Mulder, Lars and Smits, Anthal and Walles, Heike and Kock, Linda},
  title     = {Ex vivo culture platform for assessment of cartilage repair treatment strategies},
  series = {ALTEX - Alternatives to animal experimentation},
  volume    = {34},
  journal   = {ALTEX - Alternatives to animal experimentation},
  number    = {2},
  doi       = {10.14573/altex.1607111},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181665},
  pages     = {267-277},
  year      = {2017},
  abstract  = {There is a great need for valuable ex vivo models that allow for assessment of cartilage repair strategies to reduce the high number of animal experiments. In this paper we present three studies with our novel ex vivo osteochondral culture platform. It consists of two separated media compartments for cartilage and bone, which better represents the in vivo situation and enables supply of factors pecific to the different needs of bone and cartilage. We investigated whether separation of the cartilage and bone compartments and/or culture media results in the maintenance of viability, structural and functional properties of cartilage tissue. Next, we valuated for how long we can preserve cartilage matrix stability of osteochondral explants during long-term culture over 84 days. Finally, we determined the optimal defect size that does not show spontaneous self-healing in this culture system. It was demonstrated that separated compartments for cartilage and bone in combination with tissue-specific medium allow for long-term culture of osteochondral explants while maintaining cartilage viability, atrix tissue content, structure and mechanical properties for at least 56 days. Furthermore, we could create critical size cartilage defects of different sizes in the model. The osteochondral model represents a valuable preclinical ex vivo tool for studying clinically relevant cartilage therapies, such as cartilage biomaterials, for their regenerative potential, for evaluation of drug and cell therapies, or to study mechanisms of cartilage regeneration. It will undoubtedly reduce the number of animals needed for in vivotesting.},
  language  = {en}
}
@article{JannaschGaetznerWeigeletal.2017,
  author    = {Jannasch, Maren and Gaetzner, Sabine and Weigel, Tobias and Walles, Heike and Schmitz, Tobias and Hansmann, Jan},
  title     = {A comparative multi-parametric in vitro model identifies the power of test conditions to predict the fibrotic tendency of a biomaterial},
  series = {Scientific Reports},
  volume    = {7},
  journal   = {Scientific Reports},
  number    = {1689},
  doi       = {10.1038/s41598-017-01584-9},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170908},
  year      = {2017},
  abstract  = {Despite growing effort to advance materials towards a low fibrotic progression, all implants elicit adverse tissue responses. Pre-clinical biomaterial assessment relies on animals testing, which can be complemented by in vitro tests to address the Russell and Burch's 3R aspect of reducing animal burden. However, a poor correlation between in vitro and in vivo biomaterial assessments confirms a need for suitable in vitro biomaterial tests. The aim of the study was to identify a test setting, which is predictive and might be time- and cost-efficient. We demonstrated how sensitive in vitro biomaterial assessment based on human primary macrophages depends on test conditions. Moreover, possible clinical scenarios such as lipopolysaccharide contamination, contact to autologous blood plasma, and presence of IL-4 in an immune niche influence the outcome of a biomaterial ranking. Nevertheless, by using glass, titanium, polytetrafluorethylene, silicone, and polyethylene representing a specific material-induced fibrotic response and by comparison to literature data, we were able to identify a test condition that provides a high correlation to state-of-the-art in vivo studies. Most important, biomaterial ranking obtained under native plasma test conditions showed a high predictive accuracy compared to in vivo assessments, strengthening a biomimetic three-dimensional in vitro test platform.},
  language  = {en}
}
@article{JannaschWeigelEngelhardtetal.2017,
  author    = {Jannasch, Maren and Weigel, Tobias and Engelhardt, Lisa and Wiezoreck, Judith and Gaetzner, Sabine and Walles, Heike and Schmitz, Tobias and Hansmann, Jan},
  title     = {\({In}\) \({vitro}\) chemotaxis and tissue remodeling assays quantitatively characterize foreign body reaction},
  series = {ALTEX - Alternatives to Animal Experimentation},
  volume    = {34},
  journal   = {ALTEX - Alternatives to Animal Experimentation},
  number    = {2},
  doi       = {10.14573/altex.1610071},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172080},
  pages     = {253-266},
  year      = {2017},
  abstract  = {Surgical implantation of a biomaterial triggers foreign-body-induced fibrous encapsulation. Two major mechanisms of this complex physiological process are (I) chemotaxis of fibroblasts from surrounding tissue to the implant region, followed by (II) tissue remodeling. As an alternative to animal studies, we here propose a process-aligned \({in}\) \({vitro}\) test platform to investigate the material dependency of fibroblast chemotaxis and tissue remodeling mediated by material-resident macrophages. Embedded in a biomimetic three-dimensional collagen hydrogel, chemotaxis of fibroblasts in the direction of macrophage-material-conditioned cell culture supernatant was analyzed by live cell imaging. A combination of statistical analysis with a complementary parameterized random walk model allowed quantitative and qualitative characterization of the cellular walk process. We thereby identified an increasing macrophage-mediated chemotactic potential ranking of biomaterials from glass over polytetrafluorethylene to titanium. To address long-term effects of biomaterial-resident macrophages on fibroblasts in a three-dimensional microenvironment, we further studied tissue remodeling by applying macrophage-material-conditioned medium on fibrous \({in}\) \({vitro}\) tissue models. A high correlation of the \({in}\) \({vitro}\) tissue model to state of the art \({in}\) \({vivo}\) study data was found. Titanium exhibited a significantly lower tissue remodeling capacity compared to polytetrafluorethylene. With this approach, we identified a material dependency of both chemotaxis and tissue remodeling processes, strengthening knowledge on their specific contribution to the foreign body reaction.},
  language  = {en}
}