Bone Regeneration in a Mouse Model of Masquelet's Induced Membrane Technique

项目总结/摘要 由创伤、感染或癌症引起的大面积骨缺损导致成千上万的截肢者和数百万的 美元的成本。最近，一种两阶段手术方案，Masquelet诱导膜技术（MIMT）， 提出了一种革命性的方法来重建临界尺寸的缺陷，这比目前的 标准，可以为更广泛的患者群体服务。更重要的是，它提供了一个独特的机会， 发现新的骨再生生物学，其可以应用于其他骨形成情况（即， 联合、融合）和可能的其它组织。MIMT的关键特征是自体异物膜 在植入的骨水泥垫片周围形成。几周到几个月后，在第二次手术中， 并将膜隔室填充有颗粒状骨移植物。这项技术可以治愈缺陷 大至25 cm，是通过无膜移植可治疗的传统最大体积的三倍多。 然而，MIMT的再生机制完全未知。可以肯定的是， 膜是必要的。它的关键功能尚未被定义，因此没有证据可以改善它的功能。 临床应用或利用生物学原理用于其他组织再生场景。一个关键的障碍 研究MIMT机制的最大障碍是，它只在大鼠和大型动物中得到了彻底的证实。 可用于这些物种的遗传工具和试剂的数量远远少于 小鼠因此，建立一个基于鼠标的MIMT模型将是非常强大的，并允许更多的深度 研究和操作。到目前为止，只有一项研究使用小鼠进行MIMT，但第二阶段没有 尝试和第一阶段的研究设计没有很好地反映在其他物种中所做的工作。 本研究的目的是建立一个基于小鼠的MIMT模型，并将该模型与 在其他物种中是已知的，并使用仅在小鼠中可用的工具来回答一些基本的MIMT问题。我们 假设小鼠模型是可行，宿主细胞，特别是成骨细胞，主要 负责新骨的生成。为了验证这一假设，我们将首先比较/对比膜 在正常C57 BL/6 J小鼠中的骨形成和骨再生动力学与已经从其他实验中已知的一样。 特别是老鼠。在建立小鼠MIMT模型是可行的之后，我们将使用转基因技术， C57 BL/6 J小鼠，以确定宿主/移植细胞对再生的贡献。 从这些实验中获得的信息将结合起来，以靶向特定的细胞/基因/途径， 在未来的R 01中宿主/移植小鼠组织。

Project Summary/Abstract Large bone defects caused by trauma, infection, or cancer lead to thousands of amputees and millions of dollars in costs. Recently, a two-staged surgical regimen, Masquelet’s Induced Membrane Technique (MIMT), has presented a revolutionary way to reconstruct critical-sized defects that is more ideal than the current standards and could serve a wider patient population. More importantly, it presents a unique opportunity to discover new bone regeneration biology which could be applied to other bone formation situations (i.e. non- union, fusions) and possibly other tissues. The key feature of MIMT is an autologous foreign-body membrane that forms around an implanted bone cement spacer. Weeks to months later during a second surgery, the spacer is removed and the membrane compartment is filled with morselized bone graft. The technique can heal defects as large as 25 cm, more than triple the traditional maximum volume treatable via grafting without the membrane. However, MIMT’s regeneration mechanisms are completely unknown. All that is certain is that the membrane is necessary. Its critical functions have not yet been defined, so there is no evidence to improve its clinical application or harness the biological principles for other tissue regeneration scenarios. A critical barrier to investigating MIMT’s mechanisms is that it has only been thoroughly established in rats and larger animals. The number of genetic tools and reagents available for these species are far fewer than those available for mice. Thus, establishing a mouse-based MIMT model would be very powerful and allow much more in depth study and manipulation. To date, only one study has used a mouse for MIMT, but the second stage was not attempted and the first stage study design did not mirror well what has been done in other species. The goals of this proposal are to establish a mouse-based MIMT model, compare/contrast this model with what is known in other species, and use tools only available in mice to answer some fundamental MIMT questions. We hypothesize that a mouse model is feasible and that host cells, specifically osteoblasts, are mainly responsible for new bone generation. To test this hypothesis, we will first compare/contrast membrane formation and bone regeneration dynamics in normal C57BL/6J mice with what is already known from other species – most specifically rats. After establishing that a mouse MIMT model is feasible, we will use transgenic C57BL/6J mice to determine the contributions of host/graft cells to regeneration. Information gained from these experiments will be combined to target specific cells/genes/pathways in host/graft mouse tissues in a future R01.