Application of AMOR in craniofacial rabbit bone bioengineering.

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Skeletal Biology

Background:

• Tissue repair and regeneration are modulated by endogenous molecular and cellular mediators.
• Antibody-mediated osseous regeneration (AMOR) is a novel strategy for bioengineering bone using antibodies to capture endogenous bone morphogenetic proteins (BMPs).

Purpose of the Study:

• To investigate the feasibility and efficacy of AMOR in a rabbit calvarial defect model.
• To evaluate the role of specific anti-BMP-2 antibody clones in mediating bone regeneration.

Main Methods:

• Utilized a panel of anti-BMP-2 monoclonal antibodies (mAbs) and a polyclonal antibody immobilized on absorbable collagen sponge (ACS).
• Implanted the antibody-loaded ACS into critical-size calvarial defects in rabbits.
• Assessed de novo bone formation using micro-CT imaging, histology, and histomorphometric analysis after 6 weeks.

Main Results:

• Specific anti-BMP-2 mAb clones significantly mediated in vivo bone regeneration in rabbit calvarial defects.
• The reactivity of mAbs to specific epitopes on BMPs appears critical for AMOR efficacy.
• Observed increased localization of BMP-2 protein and osteocalcin expression within defects, indicating BMP accumulation and/or de novo expression.

Conclusions:

• AMOR is a feasible strategy for promoting bone regeneration in rabbit calvarial defects.
• The selection of specific anti-BMP-2 antibody clones targeting critical epitopes is essential for successful AMOR.
• Further preclinical studies in larger animal models are warranted for human translation.