rhBMP-2/calcium phosphate matrix induces bone formation while limiting transient bone resorption in a nonhuman...

Area of Science:

• Orthopedics
• Biomaterials Science
• Regenerative Medicine

Background:

• Transient bone resorption is a limitation for using recombinant human bone morphogenetic protein-2 (rhBMP-2) with absorbable collagen sponge in metaphyseal bone.
• Calcium phosphate matrix (CPM) is explored as a carrier for rhBMP-2 to potentially mitigate this resorption.

Purpose of the Study:

• To evaluate the efficacy of rhBMP-2/CPM in inducing bone formation.
• To assess the ability of rhBMP-2/CPM to limit transient bone resorption in nonhuman primate metaphyseal core defects.

Main Methods:

• Metaphyseal core defects were created in cynomolgus monkeys.
• rhBMP-2/CPM and control treatments were applied to defects in the radius, tibia, and femur.
• Bone formation and resorption were assessed using scintigraphy, radiographs, histology, and CT scans at various time points.

Main Results:

• rhBMP-2/CPM significantly increased bone formation compared to controls at eight weeks, with ongoing formation observed at twenty-four weeks.
• rhBMP-2 retention in the radius was substantial, with 78% at one day and 12% at forty-nine days.
• Transient bone resorption was observed only at the highest rhBMP-2/CPM concentration (4.5 mg/mL) in the femur at two weeks.

Conclusions:

• Treatment with 1.5 to 3.0 mg/mL rhBMP-2/CPM effectively induced bone formation in primate metaphyseal defects without causing transient bone resorption.
• rhBMP-2/CPM demonstrates potential for accelerating the healing of metaphyseal bone defects in humans.