Optimization of engineered endplates to improve in vivo integration of atissue engineered intervertebral disc

下背痛，最常见的原因是椎间盘退变， 对公众造成重大的社会和经济负担， 军人和退伍军人一样。目前椎间盘退变的临床治疗是有限的 因为它们不能恢复盘结构或功能。为了解决这个问题，我们的团队 开发了一种完整的组织工程椎间盘复合材料（eDAPS）， 纤维环、髓核和终板区域的结构。终板 由无细胞多孔聚合物泡沫组成的组件是本发明的一个关键方面。 形成工程椎间盘和天然椎骨之间界面的设计， 但还有待优化以促进血管化的加速发育， 骨感界面本研究的目的是对 eDAPS的终板区域，其将加速体内后的整合 置入我们将通过两个目标实现这一转化目标：目标1：修改 eDAPS终板区域的组成和几何形状，以增强 骨生成和新血管形成。在这个目标中，聚（ε-己内酯）（PCL）终板 将通过盐浸过程制造，并进行各种设计修改， 促进骨生成和新血管形成。PDMS模具将首先用于创建 终板内的宏观通道几何形状。终板将进一步修改 通过羟基磷灰石沉积，并掺入含有血管的微球， 内皮生长因子（VEGF）。间充质干细胞成骨潜能 羟基磷灰石改性支架将在体外建立，通过碱性 磷酸酶测定、成骨基因的qPCR分析和组织学。生物活性 也将评估从含有支架的微球释放的VEGF的量， 使用试管形成测定法体外培养。目的2：确定优化终板的效果 组织工程椎间盘的体内整合和营养设计 构建体在此目的中，将在eDAPS中使用优化的终板，以植入 在兔腰椎中体内10或20周。新生骨和血管形成 将通过钙黄绿素和茜素评价体内植入后的终板 标记和microFill增强的µCT。小分子跨终板 将通过后对比增强来评估向工程椎间盘植入物的扩散 核磁共振将评估eDAPS与自体椎体的整合强度 通过生理载荷下的拉伸、压缩和扭转机械测试。动物 eDAPS植入后的功能康复将通过活动进行评估 使用Motionwatch-8 R进行监测， 使用Tekscan系统进行扫描。拟议的工作将推进国家的艺术 在椎间盘组织工程领域，并提供见解， 将eDAPS技术转化为临床应用。

Low back pain, most commonly caused by degeneration of the intervertebral disc, places a significant social and economic burden on the general public, active duty military and veterans alike. Current clinical treatments for disc degeneration are limited in that they do not restore disc structure or function. To address this, our group has developed a whole, tissue engineered intervertebral disc composite (eDAPS) composed of engineered annulus fibrosus, nucleus pulposus and endplate regions. The endplate component, composed of an acellular porous polymer foam, is a critical aspect of the design that forms the interface between the engineered disc and native vertebral bone, but has yet to be optimized to promote the accelerated development of a vascularized, boney interface. The purpose of this study is to generate design modifications to the endplate region of the eDAPS that will accelerate integration following in vivo implantation. We will achieve this translational goal through two Aims: Aim 1: Modify the composition and geometry of the endplate region of the eDAPS to enhance osteogenesis and neovascularization. In this Aim, poly(ε-caprolactone) (PCL) endplates will be fabricated via a salt-leaching procedure with various design modifications to promote osteogenesis and neovascularization. PDMS molds will first be used to create macroscopic channel geometries within the endplates. Endplates will be further modified via hydroxyapatite deposition, and the incorporation of microspheres containing vascular endothelial growth factor (VEGF). The potential for mesenchymal stem cell osteogenesis on the hydroxyapatite modified scaffolds will be established in vitro, via the alkaline phosphatase assay, qPCR analysis of osteogenic genes, and histology. The bioactivity of the VEGF released from the microsphere containing scaffolds will also be assessed in vitro using the tube formation assay. Aim 2: Determine the effect of optimized endplate design on the in vivo integration and nutrition of a whole tissue engineered disc construct. In this Aim, optimized endplates will be utilized in eDAPS to be implanted in vivo in the rabbit lumbar spine for 10 or 20 weeks. New bone and vascular formation in the endplates following in vivo implantation will be assessed via calcein and alizarin labelling and microFil enhanced µCT, respectively. Small molecule trans-endplate diffusion into the engineered disc implants will be assessed via post-contrast enhanced MRI. Integration strength of the eDAPS with the native vertebral bodies will be assessed via tension, compression and torsional mechanical testing at physiologic loads. Animal functional rehabilitation following eDAPS implantation will be assessed via activity monitoring using the Motionwatch-8R, and ground reaction force mapping during ambulation using a Tekscan system. The proposed work will advance the state-of-the art in the field of intervertebral disc tissue-engineering, and provide insights that will speed translation of the eDAPS technology towards clinical use.