Vascular and micro-environmental influences on MSC-coral hydroxyapatite construct-based bone tissue engineering

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Orthopedic Surgery

Background:

• Bone tissue engineering (BTE) effectively generates bone tissue and repairs defects.
• Prevascularized tissue-engineered bone grafts (TEBG) for live bone graft surgery have not been previously reported.
• Quantitative benefits of vascularization and osteogenic environments for engineered bone are undefined.

Purpose of the Study:

• To develop and evaluate a prevascularized TEBG for live bone graft surgery.
• To quantitatively analyze the impact of vascularization and micro-environment on engineered bone formation.
• To assess scaffold degradation in different conditions.

Main Methods:

• Generated a TEBG with a saphenous arteriovenous vascular pedicle.
• Implanted TEBG ectopically and orthotopically in beagle dogs.
• Evaluated bone formation and scaffold degradation using CT analysis over 9 months.

Main Results:

• An organized vascular network formed within 4 weeks of implantation.
• Vascularization improved engineered bone formation twofold compared to non-vascularized grafts within 3 months.
• The bone defect micro-environment enhanced bone formation threefold compared to ectopic sites within 3 months.
• Coral hydroxyapatite (CHA) scaffold degradation was accelerated by both vascularization and the orthotopic micro-environment.

Conclusions:

• Live bone graft surgery using prevascularized TEBG is feasible and successful for bone defect repair.
• Vascularization and a conducive micro-environment are critical, quantifiable factors promoting engineered bone formation.
• These findings provide a basis for optimizing TEBG strategies for clinical applications.