Prospect of Stem Cells in Bone Tissue Engineering: A Review

Figure 4

Vascularization approaches for bone tissue engineering. (a) In vitro prevascularization techniques induce cell-seeded scaffolds to form vasculature via exogenous growth factors. Following implantation in the bone defect, these engineered capillaries will in theory rapidly anastomose to perfuse the entire graft. (b) In vivo ectopic prevascularization involves implantation of a cell-seeded scaffold into a highly vascularized bed, such as muscle or arteriovenous (AV) loop, to allow extensive vascular ingrowth. The graft is transplanted as a free flap to the bone defect and surgically anastomosed with the surrounding vessels to immediately perfuse the graft. (c) In vivo orthotopic vascularization involves direct implantation of scaffolds into the bone defect for in situ tissue development. Cells seeded into the scaffolds can be aggregated to improve cell survival and endogenous cell signaling. Scaffolds can be functionalized for the controlled release of growth factors (stars) that induce bone and vascular growth. Reprinted by permission from Elsevier Ltd., Current Opinion in Chemical Engineering, Hutton & Grayson [22], copyright © 2014.

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