Synovium-based articular cartilage tissue engineering

骨关节炎是西方国家老年人最常见的疾病之一。这种致残性关节疾病通常是多因素的性质，因此在个别情况下起源不明。在骨关节炎的早期阶段，关节软骨层的局部病变是一个特征性的事件。一旦开始，这种损伤过程是渐进的，并且没有预防措施可以阻止它。同样，没有建立的基于生物学的治疗策略可以诱导这些结构缺陷的愈合。目前正在努力采用一种生物学上更合理的方法，利用组织工程原理修复关节软骨损伤。我们最近开发了一种基于生长因子的策略，它可以诱导小关节软骨缺损的愈合。但是，当应用于实验动物（山羊）的非常大的缺陷时，同样的策略无法在短时间内诱导其修复。- 我们假设，通过自体滑膜皮瓣移植将成体干细胞群直接引入缺损空间，可以克服这些困难，并诱导大面积缺损和体积的修复。我们假设在一次干预（手术或关节镜）中进行的“分层滑膜成形术”可以形成修复大量关节软骨缺损的基础。滑膜瓣层将插入含有生长因子的基质的控释系统中，这将确保它们的转化。- 我们将首先使用基于新鲜牛滑膜组织（来自年轻成年母牛）的可用性的组织培养系统优化转化条件。- 我们还假设，体内不同滑膜关节内的成体干细胞群包含关于其分化为关节特异性关节软骨的潜能的位置信息。在这种情况下，成人滑膜干细胞的局部募集将是一个很大的优势，因为细胞将携带局部位置信息以形成相同类型的关节特异性关节软骨。我们将使用来自三种不同牛关节的关节软骨组织以及滑膜组织来测试这一假设，这些牛关节在结构和功能上都有显著差异，即，来自牛源的肩关节、膝关节和跖骨关节。- 微调后，将使用来自膝关节的成年山羊材料在体外交叉检查优化方案。最终方案将在成年山羊的中期（术后5周）和长期（术后6个月）接合处进行测试。将定量分析修复组织的mRNA表达谱和软骨基质成分的翻译后表达，以及形态学，超微结构和生物力学。我们相信，该项目具有高度创新性，该研究的结果将对骨关节炎病变的未来治疗和美国人口健康状况的改善产生重大影响。

DESCRIPTION (provided by applicant): Osteoarthritis is one of the most common diseases suffered by elderly persons in Western countries. This disabling joint disorder is usually multifactorial in nature and thus of unknown origin in individual cases. During the early stages of osteoarthritis, localized lesioning of the articular cartilage layer is a characteristic occurrence. Once initiated, this lesioning process is progressive, and no prophylactic measures are available to arrest it. Likewise, no established biologically-based treatment strategies are available to induce the healing of these structural defects. Endeavours are now being made to adopt a more biologically rational approach to the repair of articular cartilage lesions using tissue-engineering principles. We have recently developed a growth-factor-based strategy which induces the healing of small articular cartilage defects. But when applied to very large defects in experimental animals (goats), the same strategy is unable to induce their repair within a short period of time. - We postulate that by introducing an adult stem cell population directly into the defect space by the autotransplantation of synovial membrane flaps, the difficulties can be overcome and the repair of large defect areas and volumes induced. We hypothesize that a "layered synovioplasty" performed in a single intervention (surgery or arthroscopy) can form the basis for the repair of bulk volume articular cartilage defects. Layers of synovial flaps will be interposed with a matrix containing growth factors in a controlled release system, which will assure their transformation. - We will first optimize the transformation conditions using a tissue-culture system based on the availability of fresh synovial bovine tissue (from young adult cows). - We also hypothesize that adult stem cell populations within different synovial joints of the body contain positional information respecting their differentiation potential into joint- specific articular cartilage. This being the case, the local recruitment of adult synovial stem cells would be a great advantage, in that the cells would carry local positional information to form the same type of joint-specific articular cartilage. We will test this hypothesis using articular cartilage tissue as well as synovial tissue from three different bovine joints that differ significantly both structurally and functionally, i.e., from the shoulder joint, from the knee joint and from the metatarsal joint of bovine origin. - Following fine-tuning, the optimized protocols will be cross- checked in vitro using adult goat material derived from the knee joint. The finalized protocols will be tested at mid- term (5 weeks post-operatively) and long-term (6 months post-operatively) junctures in adult goats. The repair tissue will be analyzed quantitatively with respect to mRNA expression profiles and the post-translational expression of cartilage matrix components, as well as morphometrically, ultrastructurally and biomechanically. We believe that this project is highly innovative and that the results of this research will have a significant impact on the future treatment of osteoarthritic lesions and on improvement of the health status of the US population.