title: Transient exposure to transforming growth factor beta 3 under serum-free conditions enhances the biomechanical and biochemical maturation of tissue-engineered cartilage.
abstract: A goal of cartilage tissue engineering is the production of cell-laden constructs possessing sufficient mechanical and biochemical features to enable native tissue function. This study details a systematic characterization of a serum-free (SF) culture methodology employing transient growth factor supplementation to promote robust maturation of tissue-engineered cartilage. Bovine chondrocyte agarose hydrogel constructs were cultured under free-swelling conditions in serum-containing or SF medium supplemented continuously or transiently with varying doses of transforming growth factor beta 3 (TGF-beta3). Constructs were harvested weekly or bi-weekly and assessed for mechanical and biochemical properties. Transient exposure (2 weeks) to low concentrations (2.5-5 ng/mL) of TGF-beta3 in chemically defined medium facilitated robust and highly reproducible construct maturation. Constructs receiving transient TGF-beta3 exposure achieved native tissue levels of compressive modulus (0.8 MPa) and proteoglycan content (6-7% of wet weight) after less than 2 months of in vitro culture. This maturation response was far superior to that observed after continuous growth factor supplementation or transient TGF-beta3 treatment in the presence of serum. These findings represent a significant advance in developing an ex vivo culture methodology to promote production of clinically relevant and mechanically competent tissue-engineered cartilage constructs for implantation to repair damaged articular surfaces.
authors.affiliation: National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Byers
authors.forename: Robert L
authors.initials: RL
authors.lastname: Mauck
authors.forename: Ian E
authors.initials: IE
authors.lastname: Chiang
authors.forename: Rocky S
authors.initials: RS
authors.lastname: Tuan
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002356:Cartilage / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D002417:Cattle; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D020100:Hydrogels / Q000737:chemistry; D011509:Proteoglycans / Q000378:metabolism; D023822:Tissue Engineering / Q000379:methods*; D053782:Transforming Growth Factor beta3 / Q000494:pharmacology*
chemical_list: D016895:Culture Media, Serum-Free; D020100:Hydrogels; D011509:Proteoglycans; D053782:Transforming Growth Factor beta3