Ishihara K, Okazaki K, Akiyama T, Akasaki Y, Nakashima Y
Department of Orthopedic Surgery, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan.
Department of Orthopedic Surgery, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
Bone Joint Res. 2017 Feb;6(2):73-81. doi: 10.1302/2046-3758.62.BJR-2016-0199.R1.
Osteophytes are products of active endochondral and intramembranous ossification, and therefore could theoretically provide significant efficacy as bone grafts. In this study, we compared the bone mineralisation effectiveness of osteophytes and cancellous bone, including their effects on secretion of growth factors and anabolic effects on osteoblasts.
Osteophytes and cancellous bone obtained from human patients were transplanted onto the calvaria of severe combined immunodeficient mice, with Calcein administered intra-peritoneally for fluorescent labelling of bone mineralisation. Conditioned media were prepared using osteophytes and cancellous bone, and growth factor concentration and effects of each graft on proliferation, differentiation and migration of osteoblastic cells were assessed using enzyme-linked immunosorbent assays, MTS ((3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)) assays, quantitative real-time polymerase chain reaction, and migration assays.
After six weeks, the area of mineralisation was significantly higher for the transplanted osteophytes than for the cancellous bone (43803 μm, sd 14660 versus 9421 μm, sd 5032, p = 0.0184, one-way analysis of variance). Compared with cancellous bone, the conditioned medium prepared using osteophytes contained a significantly higher amounts of transforming growth factor (TGF)-β1 (471 pg/ml versus 333 pg/ml, p = 0.0001, Wilcoxon rank sum test), bone morphogenetic protein (BMP)-2 (47.75 pg/ml versus 32 pg/ml, p = 0.0214, Wilcoxon rank sum test) and insulin-like growth factor (IGF)-1 (314.5 pg/ml versus 191 pg/ml, p = 0.0418, Wilcoxon rank sum test). The stronger effects of osteophytes towards osteoblasts in terms of a higher proliferation rate, upregulation of gene expression of differentiation markers such as alpha-1 type-1 collagen and alkaline phosphate, and higher migration, compared with cancellous bone, was confirmed.
We provide evidence of favourable features of osteophytes for bone mineralisation through a direct effect on osteoblasts. The acceleration in metabolic activity of the osteophyte provides justification for future studies evaluating the clinical use of osteophytes as autologous bone grafts.Cite this article: K. Ishihara, K. Okazaki, T. Akiyama, Y. Akasaki, Y. Nakashima. Characterisation of osteophytes as an autologous bone graft source: An experimental study in vivo and in vitro. Bone Joint Res 2017;6:73-81. DOI: 10.1302/2046-3758.62.BJR-2016-0199.R1.
骨赘是软骨内成骨和膜内成骨的活跃产物，因此理论上可作为骨移植材料发挥显著功效。在本研究中，我们比较了骨赘和松质骨的骨矿化效果，包括它们对生长因子分泌的影响以及对成骨细胞的合成代谢作用。
从人类患者获取的骨赘和松质骨被移植到重度联合免疫缺陷小鼠的颅骨上，并通过腹腔注射钙黄绿素对骨矿化进行荧光标记。使用骨赘和松质骨制备条件培养基，并通过酶联免疫吸附测定、MTS（(3-(4,5-二甲基噻唑-2-基)-5-(3-羧甲氧基苯基)-2-(4-磺基苯基)-2H-四唑）测定、定量实时聚合酶链反应和迁移测定，评估每种移植物对成骨细胞增殖、分化和迁移的生长因子浓度及影响。
六周后，移植骨赘的矿化面积显著高于松质骨（43803μm，标准差14660，而松质骨为9421μm，标准差5032，p = 0.0184，单因素方差分析）。与松质骨相比，用骨赘制备的条件培养基中转化生长因子（TGF）-β1含量显著更高（471 pg/ml对333 pg/ml，p = 0.0001，Wilcoxon秩和检验）、骨形态发生蛋白（BMP）-2（47.75 pg/ml对32 pg/ml，p = 0.0214，Wilcoxon秩和检验）和胰岛素样生长因子（IGF）-1（314.5 pg/ml对191 pg/ml，p = 0.0418，Wilcoxon秩和检验）。与松质骨相比，骨赘对成骨细胞具有更强的作用，表现为更高的增殖率、分化标志物如α-1Ⅰ型胶原和碱性磷酸酶基因表达上调以及更高的迁移能力。
我们通过对成骨细胞的直接作用，提供了骨赘在骨矿化方面具有良好特性的证据。骨赘代谢活性的加速为未来评估骨赘作为自体骨移植临床应用的研究提供了依据。引用本文：K. Ishihara, K. Okazaki, T. Akiyama, Y. Akasaki, Y. Nakashima. 骨赘作为自体骨移植来源的特性：体内和体外实验研究。Bone Joint Res 2017;6:73 - 81. DOI: 10.1302/2046 - 3758.62.BJR - 2016 - 0199.R1。
