Comparison of Bone Regeneration in Different Forms of Bovine Bone Scaffolds with Recombinant Human Bone Morphogenetic Protein-2

Abstract

The aim of this study was to compare the bone regeneration ability of particle and block bones, acting as bone scaffolds, with recombinant human bone morphogenetic protein (rhBMP)-2 and evaluate them as rhBMP-2 carriers. Demineralized bovine bone particles, blocks, and rhBMP-2 were grafted into the subperiosteal space of a rat calvarial bone, and the rats were randomly divided into four groups: particle, block, P (particle)+BMP, and B (block)+BMP groups. The bone volume of the B+BMP group was significantly higher than that of the other groups (p < 0.00), with no significant difference in bone mineral density. The average adipose tissue volume of the B+BMP group was higher than that of the P+BMP group, although the difference was not significant. Adipose tissue formation was observed in the rhBMP-2 application group. Histologically, the particle and B+BMP groups showed higher formation of a new bone. However, adipose tissue and void spaces were also formed, especially in the B+BMP group. Hence, despite the formation of a large central void space, rhBMP-2 could be effectively used with block bone scaffolds and showed excellent new bone formation. Further studies are required to evaluate the changes in adipose tissue.

BMP-2 Long-Term Stimulation of Human Pre-Osteoblasts Induces Osteogenic Differentiation and Promotes Transdifferentiation and Bone Remodeling Processes

“…Since lipid droplets are often associated with adipocytes [57], it is possible that adipogenesis was promoted by BMP-2. In agreement with these data, Seok et al reported increased adipogenesis by rhBMP-2 in demineralized bovine bone particles and blocks grafted into the subperiosteal space of a rat calvarial bone [58]. Furthermore, there is the hypothesis that adipogenesis in bone marrow mesenchymal stem cells (BMSCs), the precursor cells of pre-osteoblasts, is the default pathway in the absence of osteogenic stimuli [59].…”

Long-Term Changes in Adipose Tissue in the Newly Formed Bone Induced by Recombinant Human BMP-2 In Vivo

“…Therefore, there were no significant differences in BV and BMD between the 6w and 16w block groups. As in our previous study, when rhBMP-2 was used with a block-type bone scaffold, it induced osteogenesis and adipogenesis and contributed to new bone regeneration with adipose tissue formation [ 15 ]. In contrast to its formation in the particle bone scaffold, adipose tissue was formed in the central area of the block bone scaffold and created a large vacant space.…”

“…Various scaffolds, such as collagen sponges, hydroxyapatite, and demineralized bovine bone, have been used as rhBMP-2 carriers [ 29 , 30 ]. In our previous in vivo study, rhBMP-2 was used with different forms of bone scaffolds, including particle- and block-type bovine bone, and adipose tissue and new bone formation were compared between the two groups [ 15 ]. When rhBMP-2 was used with bone particles, a void space was created between the space of the bone graft material and the newly formed bone; however, when rhBMP-2 was used with block bone, a void space was created in the central area of the scaffold [ 15 ].…”

“…In our previous in vivo study, rhBMP-2 was used with different forms of bone scaffolds, including particle- and block-type bovine bone, and adipose tissue and new bone formation were compared between the two groups [ 15 ]. When rhBMP-2 was used with bone particles, a void space was created between the space of the bone graft material and the newly formed bone; however, when rhBMP-2 was used with block bone, a void space was created in the central area of the scaffold [ 15 ]. The adipose tissue that forms inside the newly formed bone can affect the quality of the bone, and the change in this tissue needs to be evaluated for the safe clinical use of rhBMP-2.…”

“…In a previous in vivo study, the total bone and adipose tissue volumes in the grafted area were found to be higher in the bone block scaffold with rhBMP-2 than that in the bone particle scaffold with rhBMP-2. These results indicated that rhBMP-2, when used with a bone block, induced the activation of adipogenesis and osteogenesis [ 15 ]. However, there is limited information about the changes in adipose tissue inside the new bone.…”