Efficient healing of large osseous segmental defects using optimized chemically modified messenger RNA encoding...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Large osseous defects present significant clinical challenges in healing.
• Current treatments using recombinant human bone morphogenetic protein-2 (rhBMP-2) require high doses, leading to adverse effects and increased costs.

Purpose of the Study:

• To investigate the efficacy of chemically modified messenger RNA (cmRNA) encoding BMP-2 as an alternative bone regeneration strategy.
• To compare the bone healing outcomes of cmRNA-BMP-2 with conventional rhBMP-2 treatment.

Main Methods:

• Delivery of optimized BMP-2 encoding cmRNA to critical-sized femoral defects in a rat model.
• Evaluation of localized BMP-2 generation, bone defect healing, callus formation, mechanical strength recovery, and bone remodeling.
• Histological analysis to determine the mechanism of bone regeneration (endochondral vs. intramembranous ossification).

Main Results:

• cmRNA-BMP-2 effectively healed bone defects at doses of 25 μg and above.
• Treatment with 50 μg of cmRNA-BMP-2 resulted in complete bone defect bridging within 4 weeks.
• cmRNA-treated defects showed reduced callus formation, faster mechanical strength recovery, and accelerated bone remodeling compared to rhBMP-2.
• cmRNA-mediated bone regeneration occurred via endochondral ossification, distinct from rhBMP-2's intramembranous osteogenesis.

Conclusions:

• Chemically modified mRNA encoding BMP-2 is a safe, effective, and translatable technology for promoting bone healing.
• cmRNA-BMP-2 offers advantages over rhBMP-2, including localized delivery, reduced side effects, and improved healing kinetics.
• This approach represents a significant advancement in regenerative medicine for treating large osseous defects.