Coralline Hydroxyapatite Coated with a Layer Biomimetic Calcium Phosphate Containing BMP-2 Induces Dose-Related Ectopic Bone Formation in Wistar Rats

Enhanced Biocompatibility and Osteogenic Activity of Marine-Plankton-Derived Whitlockite Bone Granules through Bone Morphogenetic Protein 2 Incorporation

Whitlockite (WH) is a calcium-phosphate-based Mg-containing ceramic with good mechanical properties, rapid resorption, and good osteogenicity. Recently, we successfully synthesized highly porous WH granules using a marine plankton exoskeleton (MP-WH). In the present study, we improved the osteoinductive activity of MP-WH granules by bone morphogenetic protein2 (BMP2) (MP-WH/BMP2). The surface morphology and composition of the fabricated MP-WH/BMP2 granules were characterized using scanning electron microscopy (SEM), X-ray diffraction, and Fourier transform infrared (FT-IR) spectroscopy. The biocompatibility and osteogenic effects were evaluated using human mesenchymal stem cells (hMSCs). BMP2 was absorbed on the surfaces of the MP-WH/BMP2 granules. Immobilized BMP2 was released at a moderate rate over 30 days. hMSCs seeded on MP-WH/BMP2 granules became biocompatible, with a better proliferation and adhesion for MP-WH/BMP2, compared with MP-WH. Bone-specific markers Runx2, type I collagen, osteocalcin, and osteopontin were significantly upregulated following BMP2 incorporation. Similar observations were made regarding the alkaline phosphatase activity. This study suggests that BMP2 incorporation improves the osteoinductive activity of marine-plankton-derived WH granules for bone tissue repair.

Bone morphogenetic protein-2 incorporated calcium phosphate graft promotes peri-implant bone defect healing in dogs: A pilot study

Objectives

The evaluation of three different drug delivery modes of bone morphogenetic protein‐2 (BMP‐2) in healing peri‐implant bone defects in beagle dogs. BMP‐2 was incorporated in or onto calcium phosphate (CaP) granules in various ways: (i) directly on the outer layer of granules CaP: as an adsorbed depot; (ii) during the entire precipitation process of CaP: an internally incorporated depot; or (iii) during the biomimetic coating precipitation of BMP‐2 on the surface of CaP granules: as a coating incorporated depot.

Material and Methods

After extraction of the lower molars and wound healing in 6 male beagle dogs, 36 implants were placed (n = 6 animal per group). Peri‐implant bone defects were induced. The following treatment groups were evaluated: no treatment; air abrasive surface cleaning (SC) using hydroxyapatite; SC and the subsequent filling of the defect with CaP without BMP‐2; SC plus the subsequent filling of the defect with CaP adsorbed BMP‐2; SC plus the subsequent filling of the defect with CaP internally incorporated BMP‐2; SC plus the subsequent filling of the defect with CaP coating incorporated BMP‐2. Histological and histomorphometric analyses were carried out to quantify and compare the changes in bone tissue surrounding the treated implants.

Results

In Group 1 with no treatment, four implants were lost. Group 5 with the SC and the subsequent filling of the defect with internally incorporated BMP‐2 biomimetically prepared CaP (BioCaP), whereby the BMP‐2 is incorporated in the entire volume of all BioCaP particles, showed overall the best results to regenerate bone around the implants.

Conclusion

This study concluded that the group treated with SC plus the subsequent filling of the defect with CaP BMP‐2 internally incorporated BMP‐2, whereby BMP‐2 has been incorporated in the entire volume of all CaP particles, showed overall the best results when aiming to regenerate bone around the implants.