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

腰部疼痛，最常见的原因是椎间盘退变， 将重大的社会和经济负担强加给普通公众、现役军人 军人和退伍军人都一样。目前对椎间盘退变的临床治疗是有限的。 因为它们不恢复盘结构或功能。为了解决这个问题，我们的团队已经 开发了一种完整的组织工程化椎间盘复合材料(EDAPS)，由 工程化纤维环、髓核和终板区。端板 组件，由脱细胞多孔聚合物泡沫组成，是 在工程化盘和天然脊椎骨之间形成接口的设计， 但还有待优化，以促进血管化的加速发展， Boney界面。这项研究的目的是生成对 EDAPS的终板区，将加速体内整合 植入。我们将通过两个目标实现这一翻译目标：目标1：修改 EDAPS的端板区的组成和几何形状以增强 成骨和新生血管。在这个目的中，聚(ε-己内酯)(PCL)端板 将通过盐析程序制造，并进行各种设计修改以 促进成骨和新生血管形成。将首先使用PDMS模具来创建 端板内的宏观通道几何形状。端板将进一步改装 通过羟基磷灰石沉积和含有血管的微球的掺入 血管内皮细胞生长因子(VEGF)。间充质干细胞成骨的潜能 对羟基磷灰石修饰后的支架将在体外建立，通过碱性 磷酸酶检测、成骨基因定量聚合酶链式反应分析和组织学。生物活性 从含有支架的微球中释放的血管内皮生长因子的比例也将在 体外用试管形成试验。目的2：确定优化终板的效果 整体组织工程化盘体内整合与营养的设计 建造。为此，优化的终板将被用于eDAPS中，以植入 活体在兔腰椎内10或20周。新生骨和血管的形成 体内植入后的终板将通过钙黄绿素和茜素进行评估 分别为标签和MicroFil增强的µCT。小分子反式端板 将通过增强后检查评估进入工程化椎间盘植入物的扩散情况 核磁共振检查。将评估eDAPS与本地椎体的整合强度 通过生理载荷下的拉伸、压缩和扭转力学测试。动物 植入eDAPS后的功能康复将通过活动进行评估 使用MotionWatch-8R进行监测，并在 使用TekScan系统进行移动。拟议中的工作将推进最先进的技术 在椎间盘组织工程领域，并提供了将加快 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.