Biomimetic Hematoma Promotes Superior Bone Regeneration With Ultra-low-Dose rhBMP-2 in a Goat Large-Defect Model

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Bone regeneration often requires growth factors like recombinant human Bone Morphogenetic Protein-2 (rhBMP-2).
• Traditional delivery methods use absorbable collagen sponges (ACS), which require high rhBMP-2 doses.
• Biomimetic Hematoma (BH) scaffolds mimic natural healing environments for potentially improved delivery.

Purpose of the Study:

• To compare the efficacy of ultra-low dose rhBMP-2 in a BH scaffold versus high-dose rhBMP-2 in an ACS for large bone defect regeneration in goats.
• To evaluate if the BH scaffold enhances bone regeneration efficiency and quality compared to ACS.

Main Methods:

• Goat tibias with 2.5 cm defects were treated with BH scaffolds containing ultra-low rhBMP-2 doses (210µg, 42µg) or ACS with high-dose rhBMP-2 (2.1mg).
• Control groups included empty defects and contralateral tibias.
• Bone regeneration was assessed using radiographs, microCT, and histology at 8 weeks.

Main Results:

• BH scaffolds with both 210µg and 42µg rhBMP-2 achieved complete radiographic bone regeneration, outperforming the ACS group.
• The BH+42µg group demonstrated superior bone structural quality and predicted torsional strength.
• Histology revealed that BH+210µg rhBMP-2 produced the most mature bone architecture, while ACS+2.1mg showed dense bone filling the marrow space.

Conclusions:

• The BH scaffold facilitates effective bone regeneration with significantly lower rhBMP-2 doses compared to ACS.
• This autologous scaffold offers a biomaterial-free, precise delivery system for rhBMP-2, potentially reducing costs and adverse effects.
• The BH scaffold represents a promising advancement for treating complex bone injuries and enhancing bone repair.