Guided Bone Regeneration Using Injectable Vascular Endothelial Growth Factor Delivery Gel

Abstract

Vascularization underlies the success of guided bone regeneration (GBR) procedures. This study evaluates the regenerative potential of GBR in combination with vascular endothelial growth factor (VEGF) delivery via an injectable hydrogel system. Critical-sized defects were created in rat calvariae, and GBR procedures were performed with a collagen membrane alone (control), or plus bolus delivery of VEGF, or plus application of VEGF-releasing hydrogels (VEGF-Alg). Four and 8 weeks after treatment, defect sites were evaluated with microcomputed tomographic and histomorphometric analyses for blood vessel and bone formation. At 4 weeks, relative to the control condition, the bolus addition of VEGF did not affect blood vessel density within the defect site, yet the application of VEGF-Alg significantly (P <0.05) increased blood vessel density. Although there was no difference in bone regeneration at 4 weeks, at 8 weeks there was a significant (P <0.05) increase in bone regeneration in the VEGF-Alg-treated defects. These data demonstrate that the application of VEGF-Alg enhanced early angiogenesis, whereas at a later time point, it enhanced bone regeneration. Controlled delivery approaches of angiogenic growth factors used adjunctively with GBR may be a promising strategy for enhancing outcomes of GBR.