Nonviral gene transfer into human meniscal cells. Part II: effect of three-dimensional environment and overexpression of human fibroblast growth factor 2.

PURPOSE: Our aim was to study the effect of three-dimensional (3D) environment and overexpression of human fibroblast growth factor 2 (FGF-2) on meniscal fibrochondrocytes in vitro.
METHODS: Human meniscal fibrochondrocytes were transfected with expression plasmid vectors carrying the Photinus pyralis luciferase gene, the Escherichia coli β-galactosidase gene or a human FGF-2 cDNA. Modified fibrochondrocytes were cultivated in 3D alginate hydrogel or cell pellets or in 2D monolayer culture.
RESULTS: The levels of luciferase activity showed a peak at day two and returned to baseline levels by day 11, regardless of the type of cultivation. Both 3D environments supported the secretion of human FGF-2 protein upon FGF-2 transfection. Overexpression of human FGF-2 by genetically modified human meniscal fibrochondrocytes stimulated proliferation but not glycosaminoglycan synthesis only in 3D culture. Culture in alginate spheres resulted in a larger difference in cell numbers compared with pellet cultures.
CONCLUSIONS: Three-dimensional alginate spheres are well suited for the culture of genetically modified human meniscal fibrochondrocytes. These data are of value for cell-based approaches to meniscal repair using genetically modified human meniscal fibrochondrocytes overexpressing human FGF-2.