Transient Exposure to Transforming Growth Factor Beta 3 Under Serum-Free Conditions Enhances the Biomechanical and Biochemical Maturation of Tissue-Engineered Cartilage

• Published in: Tissue engineering. Part A 2008-11, Vol.14 (11), p.1821-1834
• Main Authors: Byers, Benjamin A., Mauck, Robert L., Chiang, Ian E., Tuan, Rocky S.
• Format: Article
• Language: English
• Subjects: Animals; Articular cartilage; Biochemistry; Biomechanical Phenomena; Biomechanics; Cartilage; Cartilage - cytology; Cartilage - drug effects; Cartilage - physiology; Cattle; Chondrocytes - cytology; Chondrocytes - drug effects; Chondrocytes - metabolism; Culture Media, Serum-Free - pharmacology; Hydrogels - chemistry; Mechanical properties; Methods; Physiological aspects; Proteoglycans - metabolism; Tissue engineering; Tissue Engineering - methods; Transforming Growth Factor beta3 - pharmacology; Transforming growth factors
• ISSN: 1937-3341; 1937-335X
• DOI: 10.1089/ten.tea.2007.0222

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-β3). 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-β3 in chemically defined medium facilitated robust and highly reproducible construct maturation. Constructs receiving transient TGF-β3 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-β3 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.