1. StarPEG/heparin-hydrogel based in vivo engineering of stable bizonal cartilage with a calcified bottom layer.
- Author
-
Kunisch E, Knauf AK, Hesse E, Freudenberg U, Werner C, Bothe F, Diederichs S, and Richter W
- Subjects
- Animals, Calcification, Physiologic, Cartilage, Articular cytology, Cartilage, Articular metabolism, Cell Proliferation, Cells, Cultured, Chondrocytes metabolism, Collagen Type X metabolism, Glycosaminoglycans chemistry, Mesenchymal Stem Cells cytology, Mesenchymal Stem Cells metabolism, Swine, Swine, Miniature, Tissue Engineering instrumentation, Cartilage, Articular growth & development, Chondrocytes cytology, Heparin chemistry, Hydrogels chemistry, Polyethylene Glycols chemistry, Tissue Engineering methods, Tissue Scaffolds chemistry
- Abstract
Repaired cartilage tissue lacks the typical zonal structure of healthy native cartilage needed for appropriate function. Current grafts for treatment of full thickness cartilage defects focus primarily on a nonzonal design and this may be a reason why inferior nonzonal regeneration tissue developed in vivo. No biomaterial-based solutions have been developed so far to induce a proper zonal architecture into a non-mineralized and a calcified cartilage layer. The objective was to grow bizonal cartilage with a calcified cartilage bottom zone wherein main tissue development is occurring in vivo. We hypothesized that starPEG/heparin-hydrogel owing to the glycosaminoglycan heparin contained as a building-block would prevent mineralization of the upper cartilage zone and be beneficial in inhibiting long-term progression of calcified cartilage into bone. MSCs were pre-cultured as self-assembling non-mineralized cell discs before a chondrocyte-seeded fibrin- or starPEG/heparin-hydrogel layer was cast on top directly before ectopic implantation. Bizonal cartilage with a calcified bottom-layer developed in vivo showing stronger mineralization compared to in vitro samples, but the hydrogel strongly determined outcome. Zonal fibrin-constructs lost volume and allowed non-organized expansion of collagen type X, ALP-activity and mineralization from the bottom-layer into upper regions, whereas zonal starPEG/heparin-constructs were of stable architecture. While non-zonal MSCs-derived discs formed bone over 12 weeks, the starPEG/heparin-chondrocyte layer prevented further progression of calcified cartilage into bone tissue. Conclusively, starPEG/heparin-hydrogel-controlled and cell-type mediated spatiotemporal regulation allowed in vivo growth of bizonal cartilage with a stable calcified cartilage layer. Altogether our work is an important milestone encouraging direct in vivo growth of organized cartilage after biofabrication.
- Published
- 2018
- Full Text
- View/download PDF