Evidence for re-differentiation of human chondrocytes seeded on a hyaluronan derivative scaffold

Association of biomaterials with autologous chondrocytes promises to provide a new generation of implantable devices for cartilage repair. HYAFF^®-11 is a recently developed hyaluronic-acid based biodegradable polymer, that has been shown to provide successful cell scaffold for tissue-engineered repair. The aim of this study was to estimate the capacity of HYAFF^®-11 to support the growth of human chondrocytes and their original phenotype. To this end, human chondrocytes (10⁶ cells/cm²) were seeded on HYAFF^®-11 and their proliferation and differentiation were assessed at different time points. Gene expression for collagen I,II and aggrecan was revealed by RT-PCR evaluating the presence of the specific mRNAs, while histochemical analyses for these proteins were performed by the use of specific monoclonal antibodies. Our data indicate that human chondrocytes seeded on HYAFF^®-11 after expansion in vitro, re-express and produce collagen type II and aggrecan and downregulate the production of collagen type I.

HYAFF^®-11 was also utilized to stabilize the phenotype of an immortalized human chondrocyte line obtained by liposome-mediated transfection with the p16HHMo plasmid encoding two HPV16 early function genes.

These results prove that normal and transfected human chondrocytes can grow and differentiate on a hyaluronan-based scaffold (HYAFF^®-11) which can be used as a delivery vehicle for the repair of articular cartilage defects.