Addition of a Synthetically Fabricated Osteoinductive Biphasic Calcium Phosphate Bone Graft to BMP2 Improves New Bone Formation.
BACKGROUND
Bone morphogenetic protein-2 (BMP2) has been successfully utilized in dentistry to promote new bone formation because of its osteoinductive ability to recruit mesenchymal progenitor cells and induce their differentiation to bone-forming osteoblasts. Recently, novel biphasic calcium phosphate scaffolds have been developed with similar osteoinductive properties capable of forming ectopic bone formation.


OBJECTIVE
The aim of the present study was to assess whether the combination of BMP2 with this novel Biphasic Calcium Phosphate (BCP) scaffold may additionally promote new bone regeneration.


METHODS
Cylindrical bone defects measuring 2.5 mm were created bilaterally in the femurs of 18 Wistar rats. After 4 weeks, the following six groups were assessed for new bone formation by micro-computed tomography (CT) as well as histological assessment: 1) collagen scaffolds + 20 μg of BMP2; 2) collagen scaffolds + 50 μg of BMP2; 3) collagen scaffolds + 100 μg of BMP2; 4) BCP scaffolds + 20 μg of BMP2; 5) BCP scaffolds + 50 μg of BMP2; and 6) BCP scaffolds + 100 μg of BMP2. Furthermore, tartrate-resistant acid phosphatase (TRAP) staining was utilized to assess osteoclast activity and osteoclast number. The release kinetics of BMP2 from both BCP and collagen scaffolds was investigated over a 14-day period.


RESULTS
The results from present study demonstrate that BMP2 is able to promote new bone formation in a concentration dependant manner when loaded with either a collagen scaffolds or BCP scaffolds. Micro-CT analysis demonstrated significantly higher levels of new bone formation in groups containing BCP + BMP2 when compared with collagen scaffolds + BMP2. BMP2 had little effect on osteoclast activity; however, less TRAP staining and osteoclast number was observed in the defects receiving collagen scaffolds when compared with BCP scaffolds. The release of BMP2 over time was rapidly released after 1 day on BCP scaffolds whereas a gradually release over time was observed for collagen scaffolds up to 14 days.


CONCLUSIONS
The osteoinductive properties of BMP2 may further be enhanced by its combination with a novel synthetically fabricated osteoinductive BCP scaffold. Future clinical testing is required to further assess these preliminary findings.
Department of Oral Implantology, School of Stomatology, Wuhan University, Wuhan, China.
Yufeng
Y
Zhang
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Shuang
S
Yang
Hangzhou Jiuyuan Gene Engineering Co, Hangzhou, China.
Wei
W
Zhou
Hangzhou Jiuyuan Gene Engineering Co, Hangzhou, China.
Hang
H
Fu
Hangzhou Jiuyuan Gene Engineering Co, Hangzhou, China.
Li
L
Qian
Department of Periodontology, Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.
Richard J
RJ
Miron
D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D005260:Female; D006882:Hydroxyapatites / Q000494:pharmacology*; D045170:Matrix Attachment Regions / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D006882:Hydroxyapatites; C074950:hydroxyapatite-beta tricalcium phosphate
BCP; bone morphogenetic protein; guided bone regeneration; osseointegration; osteoinduction