title: Engineering biomechanically functional neocartilage derived from expanded articular chondrocytes through the manipulation of cell-seeding density and dexamethasone concentration.
abstract: Recent work has established methods to engineer self-assembled, scaffold-free neocartilage from an expanded articular chondrocyte (AC) cell source. In continuing such work, the objective of the present study was to investigate the effects of cell-seeding density and dexamethasone concentration on these neocartilage constructs. Neocartilage discs (5 mm diameter) were formed by self-assembling passaged leporine articular chondrocytes into non-adherent agarose moulds. The cell-seeding densities (2, 3, 4, 5 and 6 million cells/construct) and dexamethasone concentrations (10 and 100 nm) in the culture medium were varied in a full-factorial study. After 4 weeks, the neocartilage constructs were assessed for morphological, biochemical and biomechanical properties. The cell-seeding density profoundly affected neocartilage properties. The two dexamethasone concentrations explored did not induce overall significant differences. Constructs formed using lower cell-seeding densities possessed much higher biochemical and biomechanical properties than constructs seeded with higher cell densities. Notably, the 2 million cells/construct group formed hyaline-like neocartilage with a collagen wet weight (WW) content of ~7% and a Young's modulus of ~4 MPa, representing the high end of values achieved in self-assembled neocartilage. Excitingly, the mechanical properties of these constructs were on a par with that of native cartilage tissues tested under similar conditions. Through optimization of cell-seeding density, this study shows for the first time the use of expanded ACs to form homogeneous self-assembled neocartilage with exceptionally high tensile strength. With such functional properties, these engineered neocartilage constructs provide a promising alternative for treating articular lesions. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, CA, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, CA, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Huey
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, CA, USA.
authors.forename: Jerry C
authors.initials: JC
authors.lastname: Hu
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, CA, USA.|Department of Orthopedic Surgery, University of California, Davis, CA, USA.
authors.forename: Kyriacos A
authors.initials: KA
authors.lastname: Athanasiou
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D011817:Rabbits; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D003907:Dexamethasone
keywords: cartilage; cartilage repair; cell density; dexamethasone; hyaline cartilage; juvenile chondrocytes; neocartilage; tissue engineering