Comparison of Recombinant Growth/Differentiation Factor-5 (rGDF-5) and Bone Morphogenetic Protein-2 (rBMP-2) in the In Vivo Bone Formation in Porous Hydroxyapatite Ceramic
Various recombinant growth factors have been used for promoting osteoblastic differentiation cascade. To compare the growth/differentiation factor-5 (GDF-5) and bone morphogenetic protein-2 (BMP-2) in the in vivo osteogenic potential of bone marrow mesenchymal stem cells (MSCs), the bone formation was assessed by rat subcutaneous implantation of 5 kinds of hydroxyapatite (HA) implants; namely GDF/HA composites, BMP/HA composites, MSCs/HA composites and the MSCs/HA composites supplemented with recombinant mouse GDF-5 (GDF/MSCs/HA) or recombinant human BMP-2 (BMP/MSCs/HA). Neither the GDF/HA nor the BMP/HA composites exhibited any bone formation at any time after implantation. At both 2 and 4 weeks after implantation, obvious de novo bone formation together with active osteoblasts was seen histologically in many pores of the GDF/MSCs/HA and BMP/MSCs/HA composites. The GDF/MSCs/HA and BMP/MSCs/HA composites also showed high alkaline phosphatase (ALP) and osteocalcin expression determined at both the protein and gene levels. Compared with GDF/MSCs/HA, the BMP/MSCs/HA composites exhibited excellent osteogenesis with relatively early osteoblastic phenotype expression. These findings indicate that the two growth factors synergistically enhance de novo bone formation capability of MSCs/HA composites and the importance of ceramic surface to retain and to deliver the molecules of growth factors for the cell differentiation and maturation.
Panjian Li, Kai Zhang and Clifford W. Colwell, Jr.
H. Shimaoka et al., "Comparison of Recombinant Growth/Differentiation Factor-5 (rGDF-5) and Bone Morphogenetic Protein-2 (rBMP-2) in the In Vivo Bone Formation in Porous Hydroxyapatite Ceramic ", Key Engineering Materials, Vols. 284-286, pp. 945-948, 2005