Proangiogenic potential of a collagen/bioactive glass substrate

Purpose: Previous attempts to stimulate angiogenesis have focused on the delivery of growth factors and cytokines, genes encoding for specific angiogenic inductive proteins or transcription factors, or participating cells. While high concentrations of bioactive glasses have exhibited osteogenic potential, recent studies have demonstrated that low concentrations of particular bioactive glasses are angiogenic. We hypothesized that a well known bioactive glass (Bioglass(R) 45S5) possesses proangiogenic potential over a limited range of concentrations. Materials and Methods: Varying amounts of Bioglass were loaded into absorbable collagen sponges. The proangiogenic potential of Bioglass was determined by examining the capacity of the soluble products to induce endothelial cell proliferation, tubule formation in a co-culture, and upregulate vascular endothelial growth factor (VEGF) production. Results: We determined a range of Bioglass concentrations which exhibit proangiogenic potential. Furthermore, we demonstrated that the proangiogenic capacity of this material is related to the soluble dissolution products of Bioglass and the subsequent production of cell-secreted angiogenic factors by stimulated cells. Conclusions: These studies suggest that this bioactive glass possesses a robust proangiogenic potential, and this strategy may provide an alternative to recombinant inductive growth factors.