Interface Tissue Engineering for Soft Tissue-to-Bone Integration

描述（申请人提供）：前交叉韧带（ACL）是最常见的膝关节韧带损伤，每年有超过10万例重建手术。目前，生物固定的软组织为基础的移植物重建ACL是一个重大的临床挑战。我们的生物固定方法集中在软组织和骨骼之间解剖插入部位的再生。考虑到端部细胞类型、基质组成和矿物质含量的空间差异，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的多阶段支架，由三个不同但连续的阶段组成，每个阶段都设计用于韧带，纤维软骨或acl -骨插入处的骨区域的形成。本提案的目的是优化多细胞培养和支架设计参数，用于界面再生和多组织形成。目的1将验证成骨细胞-成纤维细胞相互作用可促进软骨细胞介导的支架纤维软骨形成的假设。目的2将优化支架相特定矿物含量和分布。目的3将重点关注通过成纤维细胞、软骨细胞和成骨细胞在分层支架上的三次培养，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能否在体内维持。我们在前交叉韧带重建移植物上再生解剖纤维软骨界面的努力代表了一种创新的背离，传统的重点是骨隧道内发现的非生理性纤维软骨。此外，本文提出的用于多组织形成的多阶段支架设计和三培养方法具有高度的原创性。预计我们研究的成功完成将促进新一代综合固定装置的发展，我们的发现可以应用于许多其他情况，其中软组织与骨的整合也很重要。

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.