Viable osteogenic cells are obligatory for tissue-engineered ectopic bone formation in goats

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Research

Background:

• Cell survival is a critical factor in the success of tissue-engineered constructs in large animal models.
• Understanding the role of living cells versus extracellular matrix is crucial for optimizing bone regeneration strategies.

Purpose of the Study:

• To investigate the bone-forming capacity of vital versus devitalized tissue-engineered constructs in an ectopic goat model.
• To determine the necessity of viable bone marrow stromal cells (BMSCs) for osteogenesis within hydroxyapatite (HA) scaffolds.

Main Methods:

• Tissue-engineered (TE) constructs with vital BMSCs on HA scaffolds were compared to devitalized TE constructs, HA with bone marrow, and HA alone.
• Two types of HA scaffolds (HA70/800 and HA60/400) were evaluated for their efficacy in supporting bone formation.
• Constructs were implanted ectopically in goats, and bone formation was assessed via histology and fluorochrome labeling after 12 weeks.

Main Results:

• Bone formation was exclusively observed in vital TE constructs containing BMSCs.
• Microporous HA70/800 scaffolds demonstrated superior bone formation compared to HA60/400 scaffolds.
• Mineralization initiated from the HA surface and progressed towards the pore centers within 5 weeks.

Conclusions:

• Viable BMSCs are indispensable for achieving bone formation in TE constructs.
• The choice of HA scaffold porosity significantly influences the extent of bone regeneration.
• Successful bone regeneration requires a combination of a suitable scaffold and living, functional cells.