Tissue-engineered bone constructed in a bioreactor for repairing critical-sized bone defects in sheep

Area of Science:

• Orthopaedic surgery
• Biomaterials science
• Regenerative medicine

Background:

• Critical-sized bone defects pose significant challenges in orthopaedics.
• Previous research on bone defect repair has primarily focused on small animal models.
• Clinical translation requires validation in large animal models.

Purpose of the Study:

• To evaluate the efficacy of a novel tissue-engineered bone construct for repairing critical-sized bone defects in a large animal model (sheep).

Main Methods:

• Tissue-engineered bone was created using bone marrow mesenchymal-stem-cell-derived osteoblasts cultured on a porous beta-tricalcium phosphate (β-TCP) ceramic scaffold within a perfusion bioreactor.
• The construct was implanted into critical-sized bone defects in sheep.
• Radiographic and histological analyses were conducted at 8 and 16 weeks post-implantation.
• A control group received only the β-TCP scaffold.

Main Results:

• Radiographic evidence confirmed successful bone defect repair 16 weeks post-implantation.
• Histological analysis revealed substantial new bone formation within the β-TCP scaffold at 16 weeks.
• The tissue-engineered bone group exhibited significantly greater new bone volume compared to the β-TCP scaffold control group at both 8 and 16 weeks (P < 0.05).

Conclusions:

• Tissue-engineered bone significantly enhances osteogenesis in vivo.
• This approach demonstrates a potent capability for repairing critical-sized bone defects in large animals.
• The findings support the potential clinical application of this tissue-engineered bone in orthopaedics.