Regional Gene Therapy to Enhance Bone Repair

描述（申请人逐字）：区域基因治疗是一种新的 促进人类骨修复的方法。有人担心， 暴露于外源性重组蛋白可能不会诱导令人满意的 骨诱导性刺激在具有显著骨丢失的患者中。前几 工作，我们已经证明了离体基因转移策略的有效性 使用腺病毒基因产生的BMP-2大鼠骨髓细胞 转移这些细胞被用来愈合一个临界大小的股骨缺损， 大鼠我们现在的目标是进一步探索区域基因治疗的潜力 这样我们就能更好地将这项技术应用于人类。我们的计划是 了解离体基因骨修复过程的生物学 通过评估体内BMP产生的持续时间和定位 随着时间的推移，缺损部位的BMP分泌。此外， 转导的骨髓细胞和宿主细胞在骨修复过程中将 确定，评估对基因治疗的免疫反应和 腺病毒在不同解剖部位的存在。该研究在 具体目标1将评价另一种细胞类型（皮肤成纤维细胞）作为 潜在的细胞输送载体来治愈临界尺寸的骨缺损。的 具体目标2中提出的研究将调查前 体内腺病毒基因转移在更严格和临床相关的 通过尝试愈合成人（12月龄）和老年人（18 月龄）大鼠。在特定目的1和2中，BMP产生的持续时间 并评估BMP在缺损中的定位。在 具体目标3，BMP-2产生的骨髓细胞在骨中的作用 将在小鼠模型中评估修复过程和供体细胞。在 具体目标4，我们将：（a）比较离体基因转移的功效 用BMP-2产生骨髓细胞和直接体内注射 （B）比较这两种基因疗法的安全性和毒性 战略布局这项拟议的研究将增进我们对以下方面的了解： 基因治疗在促进骨修复方面的潜在缺陷， 让我们更接近于将这项技术应用于人类。

DESCRIPTION (Verbatim from the Applicant): Regional gene therapy is a novel approach to enhance bone repair in humans. There is concern that a single exposure to exogenous recombinant protein may not induce a satisfactory osteoinductive stimulus in patients with significant bone loss. In previous work, we have demonstrated the efficacy of an ex vivo gene transfer strategy using BMP-2-producing rat bone marrow cells created via adenoviral gene transfer. These cells were used to heal a critical-sized femoral defect in rats. Our goal now is to further explore the potential of regional gene therapy so we can better adapt this technology for humans. The plan is to enhance our understanding of the biology of the bone repair process with ex vivo gene transfer by assessing the duration of BMP production in vivo and localizing the BMP secretion in the defect site over time. In addition, the role of the transduced bone marrow cells and host cells in the bone repair process will be determined, evaluating both the immune response to gene therapy and the presence of adenovirus at various anatomic sites. The research proposed in Specific Aim 1 will evaluate another cell type (skin fibroblasts) as a potential cellular delivery vehicle to heal critical-sized bone defects. The research proposed in Specific Aim 2 will investigate the efficacy of the ex vivo adenoviral gene transfer in a more stringent and clinically relevant model by trying to heal femoral defects in adult (12 month old) and elderly (18 month old) rats. In both Specific Aims 1 and 2, the duration of BMP production in vivo and the localization of BMP in the defect will be assessed. In Specific Aim 3, the role of the BMP-2-producing bone marrow cells in the bone repair process and the donor cells will be assessed in a mouse model. In Specific Aim 4, we will: (a) compare the efficacy of the ex vivo gene transfer strategy with BMP-2-producing bone marrow cells and direct in vivo injection of the virus; and (b) compare the safety and toxicity of these two gene therapy strategies. This proposed research will enhance our knowledge with respect to the potential pitfalls of gene therapy in enhancing bone repair and hopefully take us a step closer to adapting this technology for use in humans.