Bone formation and degradation of a highly porous biphasic calcium phosphate ceramic in presence of BMP-7, VEGF and mesenchymal stem cells in an ectopic mouse model.

INTRODUCTION

Angiogenesis and mesenchymal stem cells (MSCs) promote osteogenesis. The aim of the present study was to evaluate whether bone morphogenetic protein (BMP-7) promoted osteoinduction could be enhanced by combining it with vascular endothelial growth factor (VEGF) or MSCs in highly porous biphasic calcium phosphate (BCP) ceramics.

MATERIALS AND METHODS

BCP ceramic blocks were implanted in an ectopic site in 24 mice (BMP-7 vs. BMP-7/VEGF; BMP-7 vs. BMP-7/MSCs and BMP-7 vs. Control; each group n=8). Specimens were analysed 12 weeks after surgery by environmental scanning electron microscopy (ESEM) and Giemsa staining.

RESULTS

In all implanted scaffolds, newly formed bone was observed, even in the control site. No statistical differences in the amount of new bone were found in the presence of BMP-7 compared to BMP-7/VEGF (p=1.0) or BMP-7/MSCs (p=0.786). ESEM revealed a degradation of the scaffolds. A higher degradation was observed in areas where no bone-implant contact was present compared to areas where the ceramic was integrated in newly formed bone.

CONCLUSIONS

Neither VEGF nor MSCs enhanced BMP-7 induced bone formation under the selected conditions. The present ceramic seemed to be osteoinductive and degradable, making this material suitable for bone tissue engineering.