Robert M. Crews, Jessica A. Jennings, Jonathan McCanless, Judith A. Cole, Joel D. Bumgardner, Warren O. Haggard
Minimally invasive subdermal injection of liquid silicone has been used clinically to augment the soft tissue of the foot to mitigate high pressures that cause diabetic foot ulcers. However, implant migration has been a clinical issue. The objective of this study was to assess the effects of three specific concentrations of silicone resin particles (12 μm average diameter) in conjunction with either platelet-derived growth factor (PDGF-BB) or basic fibroblast growth factor (bFGF) on fibroblast cell proliferation, collagen synthesis, cell morphology, and migration through in vitro assays and a monolayer scratch wound model. PDGF and bFGF enhanced the proliferation of fibroblasts 5.7-fold and fivefold, respectively, while the addition of silicone particles had no significant effect on proliferation. Collagen production was increased approximately twofold with the addition of bFGF and the medium concentration of particles over bFGF without particles and the PDGF groups. The addition of silicone particles had no significant effect on collagen production compared with control groups without particles. Fibroblast migration was enhanced by the addition of both PDGF and bFGF compared to controls, although slower scratch wound closure rates were observed in the presence of particles compared to controls without particles. Cell morphology suggested that particles induced cellular aggregation encircling silicone particles postwounding as well as migration into the wound area. These results suggest that silicone particles in combination with a growth factor might enhance fibroblast aggregation and implant stability, and could promote connective tissue ingrowth and implant encapsulation in the soft tissue of the diabetic foot.