Octacalcium phosphate combined with collagen orthotopically enhances bone regeneration

Abstract

Octacalcium phosphate (OCP) is resorbable bone regenerative material, but its brittleness makes it difficult to maintain its shape without restraint. We have engineered a scaffold constructed of synthetic OCP and porcine collagen sponge (OCP/Collagen) and investigated whether OCP/Collagen composite could improve bone regeneration. To examine this hypothesis, bone regeneration by the implantation of OCP/Collagen was compared with those by OCP and collagen. Radiographic and histological examination was performed and the percentage of newly formed bone (n-Bone%) in the defect was determined by a histomorphometrical analysis. OCP/Collagen, OCP, or collagen was implanted into the critical-sized defects in rat crania and fixed at 2, 4, or 8 weeks after implantation. OCP/Collagen improved the handling performance than the granules of OCP, and synergistically enhanced the bone regeneration beyond expectation, which were composed of bone nucleation by OCP and cell infiltration by collagen. Histomorphometrical analysis showed that n-Bone% +/- standard error treated with OCP/Collagen (48.4 +/- 5.14) was significantly higher than those with OCP (27.6 +/- 4.04) or collagen (27.4 +/- 5.69) in week 8. The present study suggests that the combination OCP with collagen elicited the synergistic effect for bone regeneration.

The effect of synthetic octacalcium phosphate in a collagen scaffold on the osteogenicity of mesenchymal stem cells

“…We previously showed that OCP/Col disks induce bone regeneration better than collagen disks (Kamakura et al, 2006;Kawai et al, 2009). Interestingly, in the present study we found that OCP/Col disks implanted without MSCs into bone defects enhanced bone regeneration better than collagen disks with MSCs (Figs.…”

“…3. It has been previously shown that soft x-ray conditions used for measurement do not exhibit any radiopacity in OCP/ Col disks before implantation (Kamakura et al, 2006). OCP/Col·MSCs and OCP/Col disks implanted in a rat calvaria defect showed radiopacity at 4 and 8 weeks postimplantation.…”

“…tend to be replaced with newly formed bone if implanted in experimentally created bone defects or if introduced as onlay grafts on cortical bone in various animal models (Suzuki et al, 1991;Sugihara et al, 1995;Sugihara et al, 1996;Kamakura et al, 1999;Kamakura et al, 2006;Kawai et al, 2009). OCP is known to be a potential bone apatite precursor phase (Brown et al, 1962) and is more soluble than HA or β-TCP at a physiological pH (Brown et al, 1981;Chow, 2001).…”

“…injection of sodium pentobarbital (50 mg/kg) supplemented with ether inhalation. A calvaria bone defect with a 9 mm diameter was created as previously described (Kamakura et al, 2006;Kawai et al, 2009). The OCP/Col·nor-MSCs, OCP/Col·MSCs, and Col·MSCs disks that had been cultured for 1 d were im planted into the trephine defect.…”

Biocomposites and hybrid biomaterials based on calcium orthophosphates

“…[742][743][744]783,[785][786][787][788] These biomaterials mimic natural bones to some extent, while their subsequent biological evaluation suggests that they are readily incorporated into the bone metabolism in a way similar to bone remodeling instead of acting as permanent implant. 609,731 However, the performance of these biocomposites depends on the source of the collagen from which it was processed.…”