Healing of Segmental Defects in Bone by Gene Transfer

通过基因转移修复骨节段性缺损

• 批准号: 6782751
• 负责人: CHRISTOPHER Howard EVANS
• 金额: $ 63.92万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6782751
• 关键词: autologous transplantation; biomechanics; bone morphogenetic proteins; bone regeneration; complementary DNA; gene delivery system; gene expression; gene therapy; histology; immunodeficiency; in situ hybridization; laboratory rat; morphometry; musculoskeletal disorder therapy; nonhuman therapy evaluation; osteogenesis; photon absorptiometry; tomography; transfection /expression vector

DESCRIPTION (provided by applicant): Despite the intrinsic ability of bone to heal, there are numerous clinical circumstances where bone healing is defective. One such circumstance occurs with the loss of large segments of bone, leading to critical sized defects that will not heal spontaneously. Various growth factors, including bone morphogenetic protein-2 (BMP-2), the focus of this project, stimulate new bone formation, but clinical application is hindered by delivery problems. This project is based upon the hypothesis that these problems can be overcome, and clinical utility enhanced, by delivering the gene encoding the growth factor, rather than the growth factor itself. Here, a gene transfer approach to delivering BMP-2 to critical sized segmental defects will be evaluated in a rat model. An adenovirus vector (Ad.BMP-2) will be used for this purpose. Two gene transfer strategies will be compared for safety and efficacy. In the first, virus is injected directly into the defect (in vivo delivery). In the other, autologous marrow is removed intraoperatively, mixed with vector, allowed to clot, and inserted into the defect (gene plug delivery). Healing will be assessed radiographically and by micro-computed tomography, dual-energy X-ray absorptiometry, histology, histomorphometry and by biomechanical testing. Safety will be evaluated by determining the tissue distribution of the transgenes, by histopathological examination of organs, and by immunologic criteria. As part of the safety evaluation, the effects of prolonged over-expression in athymic animals will also be determined. This information will be collated, thus permitting an informed, evidenced-based selection of the gene transfer system that is most effective and safest for possible future human application. The molecular biology of bone healing induced by the selected modality will then be further investigated. The results of this project will serve as the basis for planning early phase clinical protocols, or will have identified the critical, key matters that future research needs to address prior to developing such protocols.

描述（由申请人提供）：尽管骨具有固有的愈合能力，但在许多临床情况下骨愈合存在缺陷。其中一种情况是大块骨丢失，导致严重大小的缺损，无法自行愈合。各种生长因子，包括该项目的重点骨形态发生蛋白-2 (BMP-2)，可刺激新骨形成，但临床应用因输送问题而受到阻碍。该项目基于以下假设：通过传递编码生长因子的基因而不是生长因子本身，可以克服这些问题并增强临床实用性。在这里，将在大鼠模型中评估将 BMP-2 递送至临界尺寸节段缺损的基因转移方法。腺病毒载体（Ad.BMP-2）将用于此目的。将比较两种基因转移策略的安全性和有效性。第一种方法是将病毒直接注射到缺陷处（体内递送）。另一种方法是在术中取出自体骨髓，与载体混合，使其凝结，然后插入缺陷处（基因栓输送）。愈合情况将通过放射照相、微型计算机断层扫描、双能 X 射线吸收测定法、组织学、组织形态测定法和生物力学测试进行评估。将通过确定转基因的组织分布、器官的组织病理学检查以及免疫学标准来评估安全性。作为安全性评估的一部分，还将确定无胸腺动物中长期过度表达的影响。这些信息将被整理，从而允许对未来可能的人类应用最有效和最安全的基因转移系统进行知情、基于证据的选择。然后将进一步研究所选方式诱导的骨愈合的分子生物学。该项目的结果将作为规划早期临床方案的基础，或者将确定未来研究在制定此类方案之前需要解决的关键问题。