Gene Enhanced Tissue Engineering for Bone Regeneration

描述(由申请人提供)：新的和改进的骨再生技术的发展在许多临床应用中是可取的，特别是在牙科和颅面重建以及骨折修复方面。最佳的骨再生需要损伤部位三种成分的相互作用。这些因素包括：具有骨再生能力的适当细胞类型(S)的存在，适合细胞附着的基质，以及局部存在协调骨再生过程的调节蛋白。基因增强型组织工程骨再生方法在损伤部位结合了所有这三种成分。将分泌已知在骨再生中重要的调节蛋白的骨再生细胞组合在三维基质中，使得具有骨传导和骨诱导特性的基于基因增强的细胞复合材料被输送到该部位以获得最佳的骨再生。第一个具体目标是在颅骨骨缺损模型中直接评估三个细胞群体的骨再生能力，这三个细胞群体在骨再生过程中具有重要作用。这三种细胞来源包括骨膜来源的间充质干细胞、脂肪来源的干细胞和牙龈成纤维细胞。第二个目的是评估Sonic hedgehog(Shh)的骨再生潜力，Sonic hedgehog(Shh)是一种在颅面形态发生中起重要作用的调节蛋白。用对照和表达Shh的逆转录病毒载体稳定地转导细胞，获得表达Shh的细胞群。将在骨骼成熟的新西兰大白兔身上造成8 mm的颅骨缺损。三种类型的非转导、对照和Shh转导的同种异体细胞将被输送到由海藻酸盐和I型胶原组成的复合基质中的缺损处。其他对照包括空白缺损区和单独的海藻酸盐/I型胶原。骨再生将通过放射学和组织学进行量化。动物将在6周和12周后被处死。再生将通过测量几个有代表性的横断面上的新骨面积来进行组织学定量，以评估再生骨的厚度和闭合情况。

DESCRIPTION (provided by applicant): The development of novel and improved technologies for bone regeneration is desirable in many clinical applications, especially in dental and craniofacial reconstruction and fracture repair. Optimal bone regeneration requires the interaction of three components at the site of injury. These include: the presence of appropriate cell type(s) with bone regenerative capacity, a suitable matrix for cellular attachment, and local presence of regulatory proteins orchestrating the bone regenerative process. The gene-enhanced tissue engineering approach to bone regeneration incorporates all three components at the site of injury. Bone regenerative cells that secrete regulatory proteins of known importance in bone regeneration are combined in a three-dimensional matrix such that a gene enhanced cell based composite having both osteoconductive and osteoinductive properties is delivered to the site for optimal bone regeneration. The first specific aim is to directly evaluate in a calvarial bone defect model the bone regenerative capacity of three cell populations of reported importance in the bone regenerative process. The three cell sources include periosteal-derived mesenchymal stem cells, fat-derived stem cells, and gingival fibroblasts. The second aim is to assess the bone regenerative potential of Sonic hedgehog (Shh), a potent regulatory protein important in craniofacial morphogenesis. Cells will be stably transduced with control and Shh expressing retroviral vectors to obtain Shh expressing cell populations. Eight mm calvarial defects will be made in skeletally mature NZW rabbits. Non-, control-, and Shh-transduced allogenic cells of the three types will be delivered to the defects in a composite matrix composed of alginate and collagen I. Additional controls include empty defects and alginate/collagen I alone. Bone regeneration will be quantitated radiographically and histologically. Animals will be sacrificed after 6 and 12 weeks. Regeneration will be quantitated histologically by measuring the area of new bone in several representative cross sections to assess both thickness and closure of regenerated bone.