Repair of sheep metatarsus defects by using tissue-engineering technique

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Segmental bone defects pose significant clinical challenges.
• Current treatments often have limitations in promoting complete and rapid bone regeneration.
• Tissue engineering offers a novel approach to address these limitations.

Purpose of the Study:

• To investigate the efficacy of a tissue-engineered bone construct composed of porous beta-tricalcium phosphate (β-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSCs) in healing segmental bone defects.
• To compare the healing process with porous β-TCP ceramic alone and empty defects.

Main Methods:

• Tissue-engineered bone constructs were created by seeding autologous MSCs onto porous β-TCP scaffolds.
• Constructs were implanted into 25 mm segmental metatarsus defects in sheep (experimental group).
• Control groups received porous β-TCP only or were left empty. Radiographic, histological, and biomechanical analyses were performed at 6, 12, and 24 weeks.

Main Results:

• New bone formation was observed radiographically and histologically in the experimental group by 6 weeks, significantly earlier than the control group.
• The experimental group showed earlier formation of osteoid tissue, woven bone, and lamellar bone.
• At 24 weeks, the experimental group demonstrated near-complete defect repair, while the control group showed only partial repair. Empty defects remained unhealed.
• The engineered bone healed via direct bone formation, bypassing the typical 'creep substitution' process.

Conclusions:

• Tissue-engineered bone constructs using porous β-TCP and autologous MSCs effectively repair segmental bone defects in sheep.
• This approach promotes earlier and more complete healing compared to porous β-TCP alone.
• Porous β-TCP combined with autologous MSCs represents a viable strategy for clinical applications in treating critical-sized bone defects.