Induction of osteoblastic proliferation and phenotype development with fibroblast growth factor 2: A kinetic and tissue culture evaluation of in vitro response in two and three dimensions
Fueled by a strong commercial potential, there are a number of methodologies being explored in bone tissue engineering research in route to the development of treatments to heal void defects. One approach involves the use of cell-seeded biodegradable scaffolds, often in combination with a biological growth factor to aid in graft incorporation or healing. In order to contribute to the advancements of bone tissue engineering, this work evaluates receptor-ligand interactions and subsequent cellular response to fibroblast growth factor 2 (FGF2) in osteoblastic cells. This is done through mathematical modeling, characterization of a 3-D culture system and experimental comparison of classic static 2-D to dynamic 3-D in vitro culture. Whole cell kinetic models relating receptor mediated binding, internalization and processing of FGF2 to osteoblastic proliferative response were developed. The models explored the 3 stoichiometric representations of the proliferative signaling complex proposed in the literature. These models indicated that: (1) a piecewise assemblage of a signaling complex was found possible to occur in several ways depending on the local binding environment and (2) only 4 of 10 evaluated binding pathways, with representatives from each stoichiometry, were identified that can mimic in vitro FGF2 induced proliferation when cell surface receptors were experimentally reduced. Through extensive characterization of the 3-D dynamic culture system used in this work, internal and external fluid velocity and shear stress were measured or calculated for scaffolds cultured in commercially available bioreactors. Under these defined conditions, cell response to FGF2 was altered compared to 2-D static and 3-D static culture. This work draws renewed attention to two FGF2 signaling stoichiometries that have received less attention in recent years. The combination of experimental and modeled results provide considerable impetus to examine the possibility of multiple stoichiometries and mechanisms of formation of the FGF2 signaling complex. In addition, the comparison of 2-D and 3-D in vitro cellular response to FGF2 revealed that in vivo response to FGF2 is likely influenced not only by cell type and local concentration of FGF2 but also the presence (or absence) of fluid flow induced signaling. ^
Biology, Cell|Chemistry, Biochemistry|Engineering, Biomedical|Biophysics, General
Melissa A Dupree,
"Induction of osteoblastic proliferation and phenotype development with fibroblast growth factor 2: A kinetic and tissue culture evaluation of in vitro response in two and three dimensions"
(January 1, 2006).
Dissertations available from ProQuest.