Interface Tissue Engineering for Soft Tissue-to-Bone Integration

描述（由申请人提供）：前交叉韧带（ACL）是最常见的膝关节韧带损伤，每年进行超过100，000例重建手术。目前，ACL重建中软组织移植物的生物学固定是一个重大的临床挑战。我们的生物学固定方法的核心是软组织和骨之间的解剖插入部位的再生。考虑到细胞类型、基质组成和附着点处固有的矿物质含量的特征性空间变化，预计界面再生将需要多种细胞类型和能够支持多组织形成的分层支架。因此，我们开发了一种仿生多相支架，由三个不同但连续的相组成，每个相都设计用于形成ACL-骨插入处的韧带、纤维软骨或骨区域。本提案的目的是优化界面再生和多组织形成的多细胞培养和支架设计参数。目的1将验证成骨细胞-成纤维细胞相互作用可以促进软骨细胞介导的纤维软骨在支架上形成的假设。目标2将优化支架相特异性矿物质含量和分布。目标3将集中于通过成纤维细胞、软骨细胞和成骨细胞在分层支架上的三元培养形成四个不同但连续的组织区域（韧带、非矿化纤维软骨、矿化纤维软骨和骨）。目的4将确定这些在体外形成的仿生组织区域是否可以在体内保持。我们在ACL重建移植物上再生解剖纤维软骨界面的努力代表了对骨隧道内发现的非生理纤维软骨的传统关注的创新性偏离。此外，本文提出的多阶段支架设计和多组织形成的三代培养方法具有高度原创性。预计我们研究的成功完成将促进新一代一体化固定器械的开发，我们的研究结果可应用于软组织-骨整合也至关重要的许多其他情况。 公共卫生相关性：前交叉韧带（ACL）重建中软组织移植物的生物学固定是一个重大的临床挑战。我们认为，软组织-骨界面的再生是ACL重建中生物和合成移植物功能整合的先决条件。本项目的重点是设计和优化一种新型的仿生支架界面组织工程，使用在体外和体内的研究。由于在全国和全球范围内进行了大量ACL重建手术，计划研究的结果将对公共卫生产生重大影响。此外，该项目可以通过移植物相互整合以及与宿主环境整合形成复杂的组织系统，对组织工程移植物向临床环境的转化产生广泛的影响。

DESCRIPTION (provided by applicant): The anterior cruciate ligament (ACL) is the most frequently injured knee ligament, with over 100,000 reconstruction surgeries performed annually. Currently, the biological fixation of soft tissue-based grafts for ACL reconstruction poses a significant clinical challenge. Our approach to biological fixation centers on the regeneration of the anatomic insertion site between soft tissue and bone. Given the characteristic spatial variation in cell type, matrix composition and mineral content inherent at the enthesis, it is expected that interface regeneration will require multiple cell types and a stratified scaffold capable of supporting multi-tissue formation. Therefore, we have developed a biomimetic, multi-phased scaffold consisting of three distinct yet continuous phases, each designed for the formation of the ligament, fibrocartilage or bone regions found at the ACL-to-bone insertion. The objective of this proposal is to optimize multi-cell culture and scaffold design parameters for interface regeneration and multi-tissue formation. Aim 1 will test the hypothesis that osteoblast-fibroblast interactions can promote chondrocyte-mediated fibrocartilage formation on the scaffold. Aim 2 will optimize scaffold phase-specific mineral content and distribution. Aim 3 will focus on the formation of four distinct yet continuous tissue regions (ligament, non-mineralized fibrocartilage, mineralized fibrocartilage, and bone) through the tri-culture of fibroblasts, chondrocytes and osteoblasts on the stratified scaffold. Aim 4 will determine whether these biomimetic tissue regions formed in vitro can be maintained in vivo. Our effort to regenerate the anatomic fibrocartilage interface on ACL reconstruction grafts represents an innovative departure from the traditional focus on the non-physiologic fibrocartilage found within the bone tunnel. Moreover, the multi-phased scaffold design and tri-culture methods proposed here for multi-tissue formation are highly original. It is anticipated that the successful completion of our studies will facilitate the development of a new generation of integrative fixation devices, and our findings can be applied to many other conditions in which soft tissue-to-bone integration is also critical. PUBLIC HEALTH RELEVANCE: Biological fixation of soft tissue-based grafts for Anterior Cruciate Ligament (ACL) reconstruction poses a significant clinical challenge. We propose that the regeneration of the soft tissue-to-bone interface is a prerequisite for the functional integration of biological and synthetic grafts for ACL reconstruction. This project focuses on the design and optimization of a novel biomimetic scaffold for interface tissue engineering, using both in vitro and in vivo studies. Findings from the planned studies will have a significant impact on public health due to the large number of ACL reconstruction procedures performed nationally and worldwide. In addition, this project can have broad impact for the translation of tissue engineered grafts to the clinical setting, by enabling the formation of complex tissue systems through graft integration with each other as well as with the host environment.