Tissue Engineered Total Disc Replacement in a Large Animal Model

腰痛，这是最常见的椎间盘退变引起的，是最常见的来源 慢性疼痛的症状目前椎间盘退变的临床治疗，包括脊柱融合，是有限的 因为它们不能恢复健康椎间盘结构或功能。为了克服这一限制，我们的团队开发了 一个完整的、组织工程化终板修饰的盘状角层结构（eDAPS）， 纤维环、髓核和终板区域。到目前为止，我们已经完成了长期评估， 除了在大型动物山羊颈椎间盘中进行短期评价外， 替换模型。当前提案的首要目标是生成体外和体内数据， 推动了这项技术的首次人体试验。我们将通过以下具体措施实现这一转化目标 目的：具体目的1：评价组织工程椎间盘置换的长期功能， 在我们的大型动物模型中经受生理负荷。在这个目标中，我们将首先确定 这是组织工程椎间盘在体内的最佳长期性能所必需的固定。然后我们将 开发并测试与工程椎间盘联合使用的可吸收临时固定系统 植入物，这将消除对第二次手术的需要，并增加我们的临床可移植性 技术.具体目标2：确定组织工程椎间盘置换术恢复健康的能力 植入退行性环境时的运动节段结构和功能。在这个目标中，我们将诱导 用我们建立的软骨素酶ABC注射模型观察山羊颈椎间盘退变。 在变性进展12周后，将进行第二次手术以植入eDAPS， Aim 1中开发的可吸收固定系统。在eDAPS 1年后对动物实施安乐死 置入在此期间，将通过系列X线片和体内MRI跟踪植入物状态。自定义 将实施EMG和运动跟踪系统，以评估颈椎肌肉激活和范围 作为疼痛和功能的客观测量。在1年研究终点时，eDAPS植入物将 与未处理的退行性对照相比，通过分析整个组织的结构和功能特性， 使用多尺度和多模式方法的整个运动节段（椎间盘/植入物、小关节、神经结构）。 目的3：从人类细胞来源构建解剖组织工程椎间盘。在目标3中，我们将评估 用于接种eDAPS构建体的不同人间充质细胞来源。人骨髓 除了来源于人诱导多能干细胞的AF样和NP样细胞外， 干细胞并与天然椎间盘组织细胞进行比较。产生具有结构-功能的结构的细胞源 将利用最接近天然人类椎间盘的特性来产生尺寸适合人类腰椎的eDAPS， 颈椎总的来说，拟议的工作将大大推动eDAPS植入物的翻译， 临床应用和推进脊柱治疗学的最新发展。

Low back pain, which is most commonly caused by intervertebral disc degeneration, is the most common source of chronic pain in veterans. Current clinical treatments for disc degeneration, including spinal fusion, are limited in that they do not restore healthy disc structure or function. To overcome this limitation, our group has developed a whole, tissue engineered endplate-modified disc-like angle ply structure (eDAPS) composed of engineered annulus fibrosus, nucleus pulposus and endplate regions. To date, we have completed the long-term evaluation of the eDAPS in a small animal model, in addition to short-term evaluation in a large animal, goat cervical disc replacement model. The overarching goal of the current proposal is to generate in vitro and in vivo data to motivate the first in man trials of this technology. We will achieve this translational goal via the following specific aims: Specific Aim 1: Evaluate the long-term function of a tissue-engineered intervertebral disc replacement that is subjected to physiologic loading in our large animal model. In this Aim, we will first establish the duration of immobilization necessary for optimal long-term performance of the tissue engineered disc in vivo. We will then develop and test a resorbable provisional fixation system to be utilized in conjunction with the engineered disc implant, which will eliminate the need for a second surgery and increase the clinical translatability of our technology. Specific Aim 2: Determine the ability of a tissue-engineered disc replacement to restore healthy motion segment structure and function when implanted in a degenerative environment. In this Aim, we will induce degeneration of the goat cervical intervertebral disc using our established model of chondroitinase ABC injection. After degeneration has progressed for 12 weeks, a second surgery will be performed to implant the eDAPS with the resorbable fixation system developed in Aim 1. Animals will be euthanized after 1 year of eDAPS implantation. During this time, implant status will be tracked with serial radiographs and in vivo MRI. A custom EMG and kinematic tracking system will be implemented to assess cervical spine muscle activation and range of motion as objective measures of pain and function. At the 1 year study endpoint, eDAPS implants will be compared to untreated, degenerative controls by analyzing the structural and function properties across the whole motion segment (disc/implant, facet joints, neural structures) using a multiscale and multimodal approach. Aim 3: Fabricate anatomical tissue-engineered discs from human cell sources. In Aim 3, we will evaluate the use of different human mesenchymal cell sources for the seeding of the eDAPS constructs. Human bone marrow derived stem cells will be utilized, in addition to AF-like and NP-like cells derived from human induced pluripotent stem cells and compared to native disc tissue cells. The cell source yielding constructs with structure-function properties nearest to the native human disc will be utilized to generate eDAPS sized for the human lumbar and cervical spine. Overall, the proposed work will significantly drive the translation of the eDAPS implant towards clinical use and advance the state of the art in spine therapeutics.