Vascularization is currently considered the biggest challenge in bone tissue engineering due to necrosis in the center of large scaffolds. We established a new expendable vascular bundle model to vascularize a 3D printed channelled scaffold with and without BMP2 for improved healing of large segmental bone defects. Bone formation and angiogenesis in an 8 mm critical sized bone defect in the rat femur were significantly promoted by inserting a bundle consisting of the superficial epigastric artery and vein into the central channel of a large porous polycaprolactone scaffold. Vessels were observed sprouting from the vascular bundle inserted in the central tunnel. While the regenerated bone volume in the group receiving the scaffold and vascular bundle was similar to that of the healthy femur, the rate of union of the group was not satisfactory (25% at 8 weeks). BMP-2 delivery was found to promote not only bone formation, but also angiogenesis in the critical sized bone defects. Both insertion of the vascular bundle alone and BMP-2 loading alone induced comparable levels of angiogenesis and when used in combination, significantly greater vascular volume was observed. These findings suggest a promising new modality of treatment in large bone defects.
View details for DOI 10.1089/ten.TEA.2021.0049
View details for PubMedID 33906392