VEGF¹⁶⁵ and bFGF protein-based therapy in a slow release system to improve angiogenesis in a bioartificial dermal substitute in vitro and in vivo

Background: Angiogenesis can be enhanced by several growth factors, like vascular endothelial growth factor-165 (VEGF¹⁶⁵) and basic fibroblast growth factor (bFGF). Delayed release of such growth factors could be provided by incorporation of growth factors in fibrin matrices. In this study, we present a slow release system for VEGF¹⁶⁵ and bFGF in fibrin sealant. Materials and methods: In vitro: Pieces of Integra™ matrix of 15 mm in diameter were prepared. Integra™ matrices were divided into four groups (A=control; B=fibrin sealant; C=fibrin sealant+growth factors; D=growth factors). In vivo: The bioartificial dermal templates were transplanted into a full-skin defect of the back of nu-nu mice. Four different groups included each six matrices at 2 and 4 weeks. Results: In vitro: In groups C and D, continuous release of VEGF¹⁶⁵ and bFGF was eminent. The incorporation of growth factors into fibrin sealant evoked a prolonged growth factor release (p<0.05). In vivo: A significantly higher amount of vessels was quantified in groups C and D compared to groups A and B (p<0.001). Conclusions: A model of slow protein release by combining VEGF¹⁶⁵ and bFGF with fibrin sealant was produced. This model resulted in a prolonged bioavailability of growth factors in vivo for functional purposes. Fibrin and collagen can release growth factors in vivo and induce significant and faster neovascularisation in bioartificial dermal templates.