Oral Biotechnology and Bioengineering, Center for Dental Medicine, University of Zurich, 8032 Zurich, Switzerland.
Center for Applied Biotechnology and Molecular Medicine, University of Zurich, 8057 Zurich, Switzerland.
Int J Mol Sci. 2023 Mar 22;24(6):6000. doi: 10.3390/ijms24066000.
The early phase of bone healing is a complex and poorly understood process. With additive manufacturing, we can generate a specific and customizable library of bone substitutes to explore this phase. In this study, we produced tricalcium phosphate-based scaffolds with microarchitectures composed of filaments of 0.50 mm in diameter, named Fil050G, and 1.25 mm named Fil125G, respectively. The implants were removed after only 10 days in vivo followed by RNA sequencing (RNAseq) and histological analysis. RNAseq results revealed upregulation of adaptive immune response, regulation of cell adhesion, and cell migration-related genes in both of our two constructs. However, significant overexpression of genes linked to angiogenesis, regulation of cell differentiation, ossification, and bone development was observed solely in Fil050G scaffolds. Moreover, quantitative immunohistochemistry of structures positive for laminin revealed a significantly higher number of blood vessels in Fil050G samples. Furthermore, µCT detected a higher amount of mineralized tissue in Fil050G samples suggesting a superior osteoconductive potential. Hence, different filament diameters and distances in bone substitutes significantly influence angiogenesis and regulation of cell differentiation involved in the early phase of bone regeneration, which precedes osteoconductivity and bony bridging seen in later phases and as consequence, impacts the overall clinical outcome.
骨愈合的早期阶段是一个复杂且尚未被充分理解的过程。通过增材制造，我们可以生成特定且可定制的骨替代物文库，以探索这一阶段。在这项研究中，我们分别制造了两种基于磷酸三钙的支架，微观结构由直径为 0.50 毫米的细丝组成，分别命名为 Fil050G 和 Fil125G。植入物在体内仅 10 天后就被取出，随后进行 RNA 测序（RNAseq）和组织学分析。RNAseq 结果显示，两种结构中适应性免疫反应、细胞黏附调节和细胞迁移相关基因的表达上调。然而，仅在 Fil050G 支架中观察到与血管生成、细胞分化调节、成骨和骨发育相关的基因的显著过表达。此外，对层粘连蛋白阳性结构的定量免疫组织化学分析显示，Fil050G 样本中的血管数量明显更多。此外，µCT 检测到 Fil050G 样本中矿化组织的含量更高，表明其具有更好的骨传导能力。因此，骨替代物中不同的细丝直径和间距显著影响参与骨再生早期阶段的血管生成和细胞分化调节，这先于后期阶段的骨传导性和骨桥形成，从而影响整体临床结果。
