Decelluarized Cortical Bone Scaffold Promotes Organized Neovascularization In Vivo.

Significant bone loss due to disease or traumatic injury requires surgical intervention to modulate the natural healing process of bone. The current bone grafting options, autografts and allografts, can potentially lead to donor site morbidity or mechanical failure over time. The use of tissue engineering is a promising alternative, but the mechanical stability and integrated vasculature in vivo still remains a major challenge. In this work, we introduce a scaffold that mimics the cylindrical structure of native cortical bone and provides biological cues without the addition of growth factors to promote the differentiation of stem cells along the angiogenic lineage. Biocompatibilty of the scaffold was tested with two human endothelial cell types, human microvascular endothelial cells and human umbilical vein endothelial cells, and the angiogenic decellularized scaffold matrix led to a 78% increase in angiogenic protein secretion from human bone marrow derived stem cells. Histological analysis of the scaffolds implanted subcutaneously in the dorsum of BALB/c mice confirmed vessel development and integration at 4 weeks with a decrease in fibrous capsule thickness up to 8 weeks. Future work will need to be performed to evaluate this novel scaffold as a vascularized tissue engineered graft in a large animal model.