title: Induction of mesenchymal stem cell differentiation and cartilage formation by cross-linker-free collagen microspheres.
abstract: Because of poor self-healing ability, joint cartilage can undergo irreversible degradation in the course of various diseases or after injury. A promising approach for cartilage engineering consists of using of mesenchymal stem cells (MSC) and a differentiation factor combined with an injectable carrier biomaterial. We describe here a novel synthesis route for native collagen microspheres that does not involve the use of potentially toxic crosslinking agents. An emulsion was formed between a type I collagen solution and perfluorinated oil, stabilised by a biocompatible triblock perfluorinated copolymer surfactant. Spherical microparticles of fibrillar collagen were formed through a sol-gel transition induced by ammonia vapours. Electron microscopy observations showed that these self-cross-linked microspheres were constituted by a gel of striated collagen fibrils. Microspheres that were loaded with transforming growth factor beta (TGF-β)3 progressively released this differentiation factor over a four weeks period. Human MSC rapidly adhered to TGF-β3-loaded microspheres and, after 21 d of culture, exhibited typical chondrocyte morphology and produced an uncalcified matrix made of the predominant cartilage components, aggrecan and type II collagen, but devoid of the hypertrophic marker type X collagen. Subcutaneous co-injection of MSC and TGF-β3-loaded microspheres in mice consistently led to the formation of a cartilage-like tissue, which was however hypertrophic, calcified and vascularised. In conclusion, we developed cross-linker free collagen microspheres that allowed chondrogenic differentiation of MSC in vitro and in vivo.
authors.affiliation: Inserm U 844, Hôpital Saint-Eloi, INM, 80 Avenue Augustin Fliche, F-34091 Montpellier cedex 5, France.marc.mathieu@inserm.fr.
authors.forename: M
authors.initials: M
authors.lastname: Mathieu
authors.forename: S
authors.initials: S
authors.lastname: Vigier
authors.forename: M N
authors.initials: MN
authors.lastname: Labour
authors.forename: C
authors.initials: C
authors.lastname: Jorgensen
authors.forename: E
authors.initials: E
authors.lastname: Belamie
authors.forename: D
authors.initials: D
authors.lastname: Noël
mesh_terms: D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000502:physiology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D020219:Chondrogenesis; D024042:Collagen Type I / Q000737:chemistry / Q000494:pharmacology*; D003432:Cross-Linking Reagents / Q000633:toxicity; D006801:Humans; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D051379:Mice; D016513:Mice, SCID; D008863:Microspheres; D012038:Regeneration; D054457:Tissue Scaffolds / Q000737:chemistry; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D024042:Collagen Type I; D003432:Cross-Linking Reagents; D016212:Transforming Growth Factor beta