The primacy of octacalcium phosphate collagen composites in bone regeneration

Abstract

We have engineered a scaffold constructed of synthetic octacalcium phosphate (OCP) and porcine collagen sponge (OCP/Col), and reported that OCP/Col drastically enhanced bone regeneration. In this study, we investigated whether OCP/Col would enhance bone regeneration more than beta-tricalcium phosphate (beta-TCP) collagen composite (beta-TCP/Col) or hydroxyapatite (HA) collagen composite (HA/Col). Discs of OCP/Col, beta-TCP/Col, or HA/Col were implanted into critical-sized defects in rat crania and fixed at 4 or 12 weeks after implantation. The newly formed bone and the remaining granules of implants in the defect were determined by histomorphometrical analysis, and radiographic and histological examinations were performed. Statistical analysis showed that the newly formed bone by the implantation of OCP/Col was significantly more than that of beta-TCP/Col or HA/Col. In contrast, the remaining granules in OCP/Col were significantly lower than those in beta-TCP/Col or HA/Col. Bone regeneration by OCP/Col was based on secured calcified collagen and bone nucleation by OCP, whereas bone regeneration by beta-TCP/Col or HA/Col was initiated by poorly calcified collagen and osteoconductivity by beta-TCP or HA. This study showed that the implantation of OCP/Col in a rat cranial defect enhanced more bone regeneration than beta-TCP/Col and HA/Col.

Porous composite scaffolds based on gelatin and partially hydrolyzed α-tricalcium phosphate

“…It was demonstrated that HA precursors play an important role on osteogenesis [24]. In particular, OCP has been reported to enhance bone regeneration, when implanted in bone defects both alone and in composites with collagen [25,26]. The stimulatory effect of OCP has been related to its hydrolysis to apatite, which occurs both in vitro and in vivo [26].…”

Stimulatory Capacity of an Octacalcium Phosphate/Gelatin Composite on Bone Regeneration in a Rabbit Tibia Defect Model

“…The present conditions used for measurement do not exhibit any radiopacities in OCP/Gel disks before implantation in the pilot study; thus, the increase of the radiopacity should stand for the enhancement of mineralization or new bone formation, as previously reported. [7][8][9][10] Although the size of the bone defect tended to decrease in both the OCP/Gel-implanted group and the control (defect only) group at 2 weeks, thicker radiopacity was apparent in the OCP/Gel group than in the control group. Bone defects were completely restored and continued with bone cortex, even in the bone defect of control at 4 weeks.…”

“…In fact, OCP and OCP-based materials with natural polymers, such as OCP/collagen composite, enhance bone regeneration coupled with their own biodegradation in various experimentally created bone defects. [4][5][6][7][8] From the viewpoint of bone regenerative properties, autologous bone is still the first choice for filling defects due to its superior osteoconductivity, since autologous bone consists of osteoblastic cells, growth factors, such as bone morphogenetic proteins, and matrix materials, including collagen and hydroxyapatite (HA) crystals. Although the tissue-engineering technique by introducing exogenous cells into the OCP-based material certainly increases the osteogenic capability of the material, 9 the use of bone-substitute materials that have biological activity compatible with that of autologous bone, with the stimulation of host osteoblastic cells around OCP crystals, is still preferable from the viewpoint of reducing the complex handling and the cost of the preparation of an implant form.…”

Hydroxyapatite agarose composite gels as a biochemical material for the repair of alveolar bone defects due to cleft lip and palate

“…For example, TCP/MCPM/C3S comprises tricalcium silicate (Ca 3 SiO 5 , C 3 S) added to ␤-TCP or monocalcium phosphate monohydrate (Ca(H 2 PO 4 )2H 2 O, MCPM) to form a bioactive new bone cement, called octacalcium phosphate collagen composite [12], which is reported to gradually convert into HAp [13] with good results.…”