@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{FahmyGarciaFarrellWitteBoumaetal.2019,
  author    = {Fahmy-Garcia, Shorouk and Farrell, Eric and Witte-Bouma, Janneke and Robbesom-van den Berge, Iris and Suarez, Melva and Mumcuoglu, Didem and Walles, Heike and Kluijtmans, Sebastiaan G. J. M. and van der Eerden, Bram C. J. and van Osch, Gerjo J. V. M. and van Leeuwen, Johannes P. T. M. and van Driel, Marjolein},
  title     = {Follistatin Effects in Migration, Vascularization, and Osteogenesis in vitro and Bone Repair in vivo},
  series = {Frontiers in Bioengineering and Biotechnology},
  volume    = {7},
  journal   = {Frontiers in Bioengineering and Biotechnology},
  doi       = {10.3389/fbioe.2019.00038},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227617},
  year      = {2019},
  abstract  = {The use of biomaterials and signaling molecules to induce bone formation is a promising approach in the field of bone tissue engineering. Follistatin (FST) is a glycoprotein able to bind irreversibly to activin A, a protein that has been reported to inhibit bone formation. We investigated the effect of FST in critical processes for bone repair, such as cell recruitment, osteogenesis and vascularization, and ultimately its use for bone tissue engineering. In vitro, FST promoted mesenchymal stem cell (MSC) and endothelial cell (EC) migration as well as essential steps in the formation and expansion of the vasculature such as EC tube-formation and sprouting. FST did not enhance osteogenic differentiation of MSCs, but increased committed osteoblast mineralization. In vivo, FST was loaded in an in situ gelling formulation made by alginate and recombinant collagen-based peptide microspheres and implanted in a rat calvarial defect model. Two FST variants (FST288 and FST315) with major differences in their affinity to cell-surface proteoglycans, which may influence their effect upon in vivo bone repair, were tested. In vitro, most of the loaded FST315 was released over 4 weeks, contrary to FST288, which was mostly retained in the biomaterial. However, none of the FST variants improved in vivo bone healing compared to control. These results demonstrate that FST enhances crucial processes needed for bone repair. Further studies need to investigate the optimal FST carrier for bone regeneration.},
  language  = {en}
}