Targeted Integration of Tissue Engineered Cartilage

描述(申请人提供)：本研究项目的总体目标是将组织工程软骨与天然组织相结合。具体地说，我们将通过在光聚合水凝胶和软骨细胞外基质之间建立共价键来实现这一目标。软骨是一种无血管组织，在许多其他组织中起着缓冲和润滑面的作用，为关节功能提供适当的关节功能。软骨由于创伤、疾病或先天畸形而丢失，缺乏自我修复能力，因此一直是组织工程学研究的重点。例如，我们已经研究了光聚合水凝胶支架，这种支架可以用分化的软骨细胞和骨髓间充质干细胞原位形成工程软骨。不幸的是，将这项研究转化为成功的临床应用仍然存在许多障碍。组织工程软骨与天然宿主组织的整合仍然是翻译这项研究的最大挑战之一。由于缺乏与周围组织的结合，植入物会发生微动，常常会导致脱位。此外，移植组织的细胞外基质很少与宿主形成连续的网络，这阻碍了适当的组织维护，并最终导致植入失败。与其他专注于改进支架或植入技术的组织工程策略不同，我们专注于对天然软骨组织进行修饰，以启动聚合和支架形成。我们建议通过设计一种方法来解决这个问题，将组织工程支架直接共价连接到天然软骨中的强胶原纤维上，将改善组织整合，防止植入物移动，同时为工程软骨和天然软骨细胞外基质的整合提供桥梁。此外，我们开发的技术，组织引发的光聚合，允许在没有外源光引发剂的情况下原位形成水凝胶，提高了生物相容性。为了实现设计一种新型的水凝胶与软骨整合的体系，并验证其将促进基质整合的假设，已经开发了以下具体目标：具体目标1.发展一种高效且生物相容的方法，将光聚合水凝胶直接结合到软骨组织上。具体地说，胶原纤维会暴露在软骨表面并被氧化，产生自由基，引发光聚合。具体目的2.通过细胞-水凝胶构建物在软骨表面的共价附着，促进软骨细胞与骨髓间充质细胞和宿主软骨基质在体内外的整合。组织整合将通过形态、生化和机械分析进行监测。

DESCRIPTION (provided by applicant): The overall goal of this research project is to integrate tissue engineered cartilage with native tissue. Specifically, we will achieve this goal by creating covalent bonds between a photopolymerizing hydrogel and the cartilage extracellular matrix. Cartilage is an avascular tissue that acts as a cushion and lubricating surface for proper articulating joint function and provides smactural function in numerous other tissues. Cartilage has been the focus of significant tissue engineering research since it lacks the ability to self repair when it is lost due to trauma, disease, or congenital abnormalities. For example, we have investigated photopolymerizing hydrogel scaffolds that may be formed in situ for engineering cartilage using differentiated chondrocytes and bone marrow-derived mesenchyrnal stem cells. Unfortunately, numerous barriers remain for translating this research to a successful clinical application. Integration of tissue-engineered cartilage with the native host tissue remains one of the most significant challenges in translating this research. Lack of integration with the surrounding tissues allows micromotion of the implant to occur, often causing dislocation. Furthermore, the extracellular matrix of the transplanted tissue rarely forms a contiguous network with the host which prevents proper tissue maintenance and ultimately leads to implant failure. Unlike other tissue engineering strategies that focus on improving the scaffold or implantation technique, we have focused on modifying the native cartilage tissue in order to initiate polymerization and scaffold formation. We propose to solve this problem by designing a method to covalently attach a tissue engineering scaffold directly to the strong collagen fibers in native cartilage will improve tissue integration, preventing implant movement while providing a bridge for engineered and native cartilage extracellular matrix to integrate. Furthermore, the technique we have developed, tissue-initiated photopolymerization, allows in situ hydrogel formation to occur without an exogenous photoinitiator, improving biocompatibility. To achieve the goal of designing a novel system for hydrogel integration to cartilage and testing the hypothesis that it will improve matrix integration the following specific aims have been developed: Specific Aim 1. Development of an efficient and biocompatible method to directly bond a photopolymerizing hydrogel to cartilage tissue. Specifically, collagen fibers will be exposed on the cartilage surface and oxidized to generate a radical and initiate photopolymerization. Specific Aim 2. Test the hypothesis that covalent attachment of a cell-hydrogel construct to the cartilage surface will improve integration of cartilage engineered from chondrocytes and bone marrow-derived mesenchymal cells and host cartilage matrix both in vitro and in vivo. Tissue integration will be monitored by morphological, biochemical, and mechanical analysis.