Department of Chemical, Biological and Pharmaceutical Engineering, New Jersey Institute of Technology, Newark, New Jersey, 07102, USA.
Department of Biomedical Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey, 07102, USA.
AAPS J. 2017 Jul;19(4):1017-1028. doi: 10.1208/s12248-017-0073-9. Epub 2017 Mar 22.
Large bone defects often require the use of autograft, allograft, or synthetic bone graft augmentation; however, these treatments can result in delayed osseous integration. A tissue engineering strategy would be the use of a scaffold that could promote the normal fracture healing process of endochondral ossification, where an intermediate cartilage phase is later transformed to bone. This study investigated vanadyl acetylacetonate (VAC), an insulin mimetic, combined with a fibrous composite scaffold, consisting of polycaprolactone with nanoparticles of hydroxyapatite and beta-tricalcium phosphate, as a potential bone tissue engineering scaffold. The differentiation of human mesenchymal stem cells (MSCs) was evaluated on 0.05 and 0.025 wt% VAC containing composite scaffolds (VAC composites) in vitro using three different induction media: osteogenic (OS), chondrogenic (CCM), and chondrogenic/osteogenic (C/O) media, which mimics endochondral ossification. The controlled release of VAC was achieved over 28 days for the VAC composites, where approximately 30% of the VAC was released over this period. MSCs cultured on the VAC composites in C/O media had increased alkaline phosphatase activity, osteocalcin production, and collagen synthesis over the composite scaffold without VAC. In addition, gene expressions for chondrogenesis (Sox9) and hypertrophic markers (VEGF, MMP-13, and collagen X) were the highest on VAC composites. Almost a 1000-fold increase in VEGF gene expression and VEGF formation, as indicated by immunostaining, was achieved for cells cultured on VAC composites in C/O media, suggesting VAC will promote angiogenesis in vivo. These results demonstrate the potential of VAC composite scaffolds in supporting endochondral ossification as a bone tissue engineering strategy.
大骨缺损常需要使用自体移植物、同种异体移植物或合成骨移植增强物；然而，这些治疗方法可能导致骨整合延迟。组织工程策略将使用支架来促进骺软骨内骨化的正常骨折愈合过程，其中中间软骨阶段随后转化为骨。本研究调查了乙酰丙酮氧钒 (VAC)，一种胰岛素模拟物，与由聚己内酯和纳米羟基磷灰石和β-磷酸三钙组成的纤维复合支架结合，作为一种潜在的骨组织工程支架。通过三种不同的诱导培养基：成骨培养基 (OS)、软骨形成培养基 (CCM) 和软骨形成/成骨培养基 (C/O)，评估 0.05 和 0.025wt%VAC 含复合支架（VAC 复合材料）体外对人间充质干细胞 (MSCs) 的分化，该培养基模拟骺软骨内骨化。VAC 复合材料在 28 天内实现了 VAC 的控制释放，在此期间释放了大约 30%的 VAC。在 C/O 培养基中培养的 VAC 复合材料上的 MSCs 具有增加的碱性磷酸酶活性、骨钙素产生和胶原蛋白合成超过复合支架无 VAC。此外，VAC 复合材料上的软骨形成标志物 (Sox9) 和肥大标志物 (VEGF、MMP-13 和胶原 X) 的基因表达最高。在 C/O 培养基中培养的细胞的 VEGF 基因表达和 VEGF 形成增加了近 1000 倍，如免疫染色所示，表明 VAC 将促进体内血管生成。这些结果表明 VAC 复合材料支架在支持作为骨组织工程策略的骺软骨内骨化方面具有潜力。
