Interaction between cartilage / subchondral interfaces and MSC in vitro and in vivo

具有关节特征的组织工程化功能软骨的体外生产仍有待优化，软骨缺损的体内再生是一个真实的挑战。为了有效地解决这些问题，更好地了解微环境的线索和邻近细胞和组织界面对软骨祖细胞的软骨分化的调节影响是必不可少的。在这项研究中，我们分析了软骨/软骨下骨表面对间充质干细胞（MSC）软骨分化和再生组织特性的影响。我们已经发现，接触骨关节炎关节软骨和软骨下骨表面抑制基因表达和生物合成的结构分子在分化的软骨细胞和未分化的MSC。将人体外共培养系统适应绵羊系统将允许比较病理性OA组织的反应与健康组织的反应。随后，我们将使用1）软骨形成预分化的自体MSC和2）MSC与自体软骨细胞的混合培养物（均在纤维蛋白凝胶结构中），将基于细胞的植入物整合到大型动物绵羊模型中的局灶性全层软骨缺损中。这将使我们能够测试来自微环境中分化细胞的信号的影响，并分析体内软骨界面和植入细胞之间的相互作用。在这个后续项目中，我们追求两个主要目标：1。 我们希望鉴定来自晚期OA组织/软骨细胞的负责抑制因子，其调节基因和蛋白质表达2。 我们想分析健康（或早期OA）软骨组织和MSC在体内的相互作用

Ex vivo production of tissue-engineered functional cartilage with articular characteristics remains still to be optimized and in vivo regeneration of chondral defects is a real challenge. To effectively address the problems, a better understanding of microenvironmental cues and the modulating influence of neighbouring cells and tissue interfaces on chondrogenic differentiation of chondroprogenitor cells are essential. In this study, we are analysing the impact of cartilage/subchondral bone surfaces on chondrogenic differentiation of mesenchymal stem cells (MSC) and properties of regenerated tissue. We have detected that contact to osteoarthritic articular cartilage and subchondral bone surfaces represses gene expression and biosynthesis of structural molecules in differentiated chondrocytes and undifferentiated MSC. Adaptation of the human in vitro coculture systems to the ovine system will allow a comparison of the response of pathological OA-tissues with the response of healthy tissues. Subsequently, we will integrate cell-based implants into focal full-thickness chondral defects in a large animal sheep model using 1) chondrogenically pre-differentiated autologous MSC and 2) a mixed culture of MSC with autologous chondrocytes, both in fibrin gel constructs. This will allow us to test the influence of signals from differentiated cells in the microenvironment and to analyse the interaction between the chondral interface and the implanted cells in vivo. In this follow up project we pursue two main goals:1. We want to identify responsible repressive factor(s) derived from late OA-tissue/chondrocytes which modulate gene and protein expression 2. We want to analyse the interaction between healthy (or early OA) cartilage tissue and MSC in vivo