Linkage of chondroitin-sulfate to type I collagen scaffolds stimulates thebioactivity of seeded chondrocytes in vitro

An increasing amount of interest is focused on the potential use of tissue- engineered articular cartilage implants, for repair of defects in the joint surface. In this perspective, various biodegradable scaffolds have been ev aluated as a vehicle to deliver chondrocytes into a cartilage defect. This cell-matrix implant should eventually promote regeneration of the traumatiz ed articular joint surface with hyaline cartilage. Successful regeneration can only be achieved with such a tissue-engineered cartilage implant if the seeded cells reveal an appropriate proliferation rate in the biodegradable scaffold together with the production of a new cartilage-specific extracel lular matrix. These metabolic parameters can be influenced by the biochemic al composition of a cell-delivery scaffold. Further elucidation of specific cell-matrix interactions is important to define the optimal biochemical co mposition of a cell-delivery vehicle for cartilage repair. In this in vitro study, we investigated the effect of the presence of cartilage-specific gl ycosaminoglycans in a type I collagen scaffold on the metabolic activity of seeded chondrocytes. Isolated bovine chondrocytes were cultured in porous type I collagen matrices in the presence and absence of covalently attached chondroitin sulfate (CS) up to 14 days. CS did indeed influence the bioact ivity of the seeded chondrocytes. Cell proliferation and the total amount o f proteoglycans retained in the matrix, were significantly higher (p < 0.00 1) in type I collagen scaffolds with CS. Light microscopy showed the format ion of a more dense cartilaginous layer at the matrix periphery. Scanning e lectron microscopy revealed an almost complete surfacing of the initially p orous surface of both matrices. Histology and reverse transcriptase PCR for various proteoglycan subtypes suggested a good preservation of the chondro cytic phenotype of the seeded cells during culture. The stimulatory potenti al of CS on both the cell-proliferation and matrix retention, turns this GA G into an interesting biochemical component of a cell-delivery scaffold for use in tissue-engineering articular cartilage. (C) 2001 Elsevier Science L td. All rights reserved.