BACKGROUND: Genetically engineered chondrocytes could be used to enhance cartilage repair. Fibroblast growth factor 2 (FGF-2) is a mitogen for chondrocytes and may be a candidate for gene transfer approaches to stimulate chondrocyte proliferation. In the present study, we tested the hypothesis that human FGF-2 (hFGF-2) gene transfer into articular chondrocytes modulates cell proliferation in an ex vivo model of chondrocyte transplantation. METHODS: Transfection of articular chondrocytes with an expression plasmid vector carrying the cDNA for hFGF-2 under the control of the cytomegalovirus promoter/enhancer mediated transgene expression and synthesis of biologically relevant amounts of the recombinant hFGF-2 protein. Articular chondrocytes transfected with the Escherichia coli beta-galactosidase (lacZ) gene or a hFGF-2 cDNA were transplanted onto the surface of articular cartilage explants. RESULTS: The tissue formed by the chondrocytes expressing hFGF-2 was thicker and contained more cells than control cultures. Quantitative analysis of [(3)H]thymidine and [(35)S]sulfate incorporation in composite cultures revealed that hFGF-2 transfection stimulated mitogenic activity in the new tissue but did not augment matrix glycosaminoglycan synthesis. CONCLUSIONS: These data support the concept that chondrocytes overexpressing a hFGF-2 cDNA selectively modulate cell proliferation in an ex vivo model of chondrocyte transplantation. These results suggest that therapeutic hFGF-2 gene transfer may be applicable for the treatment of articular cartilage disorders, such as traumatic defects in which cellular repopulation is a therapeutic goal. Copyright 2004 John Wiley & Sons, Ltd.
BACKGROUND: Genetically engineered chondrocytes could be used to enhance cartilage repair. Fibroblast growth factor 2 (FGF-2) is a mitogen for chondrocytes and may be a candidate for gene transfer approaches to stimulate chondrocyte proliferation. In the present study, we tested the hypothesis that humanFGF-2 (hFGF-2) gene transfer into articular chondrocytes modulates cell proliferation in an ex vivo model of chondrocyte transplantation. METHODS: Transfection of articular chondrocytes with an expression plasmid vector carrying the cDNA for hFGF-2 under the control of the cytomegalovirus promoter/enhancer mediated transgene expression and synthesis of biologically relevant amounts of the recombinant hFGF-2 protein. Articular chondrocytes transfected with the Escherichia coli beta-galactosidase (lacZ) gene or a hFGF-2 cDNA were transplanted onto the surface of articular cartilage explants. RESULTS: The tissue formed by the chondrocytes expressing hFGF-2 was thicker and contained more cells than control cultures. Quantitative analysis of [(3)H]thymidine and [(35)S]sulfate incorporation in composite cultures revealed that hFGF-2 transfection stimulated mitogenic activity in the new tissue but did not augment matrix glycosaminoglycan synthesis. CONCLUSIONS: These data support the concept that chondrocytes overexpressing a hFGF-2 cDNA selectively modulate cell proliferation in an ex vivo model of chondrocyte transplantation. These results suggest that therapeutic hFGF-2 gene transfer may be applicable for the treatment of articular cartilage disorders, such as traumatic defects in which cellular repopulation is a therapeutic goal. Copyright 2004 John Wiley & Sons, Ltd.