Angiogenesis & Osteogenesis in Structural Graft Healing

描述（由申请人提供）：由于皮质骨自体移植物的供应有限以及结构性同种异体移植物获得的长期结局较差，大型结构性骨缺损的修复仍然是骨科重建手术中的主要问题。虽然没有结构性同种异体移植物的替代品，但基于其生物力学和生物相容性，它们缺乏成骨和骨诱导潜力，加上宿主无法重塑加工的皮质骨，导致骨折的比例很高。为了阐明调节结构性骨移植愈合的细胞和分子机制，我们建立了小鼠股骨节段同种异体移植模型。使用这个模型，我们能够证明自体移植愈合是上级的观察与同种异体移植由于血管生成和成骨活性活骨膜细胞。我们还开发了将细胞和/或重组腺相关病毒（rAAV）植入股骨同种异体移植物皮质表面的新方法。基于此，我们假设：1）同种异体移植物愈合和后期修复受到血管生成和成骨细胞缺乏的限制。2)使用基于细胞的组织工程方法和/或基于AAV的基因疗法使无生命的同种异体移植物再生将赋予经处理的皮质骨血管生成、成骨和重塑性质，从而导致增强的骨同种异体移植物愈合。在我们的第一个特定目标中，我们将利用我们的鼠股骨骨移植模型进行来自C57 B/6 Rosa 26 A雄性小鼠的活同种移植物的移植，以正式证明骨膜供体细胞在结构性骨移植物血运重建、成骨和重塑中的贡献，在我们的第二个特定目标中，我们将骨髓基质细胞接种到处理过的同种异体骨上，以检测它们对冷冻同种异体骨愈合和重建的功效。在我们的第三个目标中，我们将结合联合收割机和rAAV基因治疗，以补充处理过的结构性同种异体移植物与活细胞和血管生成-成骨信号，并比较其愈合与自体移植物和同种异体移植物。

DESCRIPTION (provided by applicant): Repair of large structural bone defects remains a major problem in orthopaedic reconstruction surgery due to the limited supply of cortical bone autograft and the poor long-term outcomes obtained with structural allografts. While there is no substitute for structural allografts, based on their biomechanical and biocompatible properties, their lack of osteogenic and osteoinductive potential, combined with the host's inability to remodel processed cortical bone, results in a high percentage of fractures. Towards elucidating the cellular and molecular mechanisms that regulate structural bone graft healing, we have developed a murine femoral segmental allograft model. Using this model we were able to demonstrate that autograft healing is superior to that observed with allografts due to the angiogenic and osteogenic activity from live periosteal cells. We have also developed novel approaches to engraft cells and/or recombinant adeno-associated viruses (rAAV) on the cortical surface of the femoral allografts. Based on this, we hypothesize that: 1) allograft healing and later repair is limited by the absence of angiogenic and osteogenic cells. 2) Revitalization of lifeless allograft using a cell based tissue engineering approach and/or AAV based gene therapy will confer angiogenic, osteogenic and remodeling properties on processed cortical bone leading to enhanced bone allograft healing. In our first Specific Aim, we will utilize our murine femoral bone graft model to perform transplantation of live isografts from C57B/6 Rosa 26A male mice to formally demonstrate the contributions of periosteal donor cells in structural bone graft revascularization, osteogenesis and remodeling, in our second Specific Aim, we will seed bone marrow stromal cells onto processed allograft to examine their efficacy on bone healing and remodeling of frozen allograft. In our third aim, we will combine stem cell engraftment and rAAV gene therapy to complement processed structural allograft with live cells and angiogenic-osteogenic signals, and compare its healing with autograft and allograft.