Efficacy of prevascularization for segmental bone defect repair using β-tricalcium phosphate scaffold in rhesus monkey

Although small animal model (rabbit) showed successful bone defect repair using prevascularized tissue-engineered bone grafts (TEBG), large animal (rhesus monkey) studies are still needed to extrapolate the findings from animal data to humans. In current study, we investigated the efficacy of prevascularized TEBG for segmental bone defect repair in rhesus monkey. The segmental diaphyseal defects were created in both tibias. In group A, the defect was filled with prevascularized MSCs/scaffold prepared by inserting saphenous vascular bundle into the side groove and a fascia flap coverage; In group B, the defect was filled with MSCs/scaffold with a fascia flap coverage; In group C, the defect was filled with MSCs/scaffold; In group D, the defect was filled with only scaffold. The angiogenesis and new bone formation were compared among groups at 4, 8, and 12 weeks postoperatively. The results showed the prevascularized TEBG in group A could augment new bone formation and capillary vessel in-growth. It had significantly higher values of vascularization and radiographic grading score compared with other groups. In conclusion, the in vivo experiment data of prevascularized TEBG was further enriched from small to large animal model. It implies that prevascularized TEBG has great potentials in clinical applications.