Tissue engineering application of endochondral ossification for bone regeneration

软骨内骨化在骨再生中的组织工程应用

• 批准号: 8256413
• 负责人: Chelsea Shields Bahney
• 金额: $ 4.92万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8256413
• 关键词: Address; Adipose tissue; Adult; Apoptosis; Autologous Transplantation; Biological; Bone Development; Bone Marrow; Bone Regeneration; Bone Tissue; Bone Transplantation; Bone callus; Bone necrosis; Cartilage; Cells; Chondrocytes; Chondrogenesis; Clinical; Data; Defect; Development; Developmental Process; Encapsulated; Engineering; Event; Excision; Extracellular Matrix Proteins; Failure; Fracture; Fracture Healing; Genetic; Goals; Gold; Healed; Health; Histologic; Human; Hydrogels; Impaired wound healing; In Vitro; Label; Matrilysin; Matrix Metalloproteinases; Mechanics; Mesenchymal Stem Cells; Molecular; Multipotent Stem Cells; Mus; Musculoskeletal; Natural regeneration; Operative Surgical Procedures; Osteogenesis; Osteotomy; Outcome; Pathway interactions; Phenotype; Procedures; Process; Productivity; Property; Protocols documentation; Research; Research Proposals; Series; Skeleton; Spinal Fusion; Stem cells; System; Techniques; Technology; Testing; Time; Tissue Engineering; Tissue Grafts; Tissues; Translating; Translations; Transplantation; Trauma; United States; Vascularization; Work; base; bone; bone quality; career; clinical application; clinically relevant; design; healing; improved; in vivo; in vivo Model; intramembranous bone formation; long bone; meetings; mineralization; mouse model; new technology; poly(ethylene glycol)diacrylate; repaired; response; scaffold; skills; success; tibia; tumor

DESCRIPTION (provided by applicant): Bone graft technologies currently available to treat large segmental defects typically generate replacement tissue with poor vascularity and poor host integration that leads to clinical failures associated with osteonecrosis or dislodgement. As a result, there is a significant unmet need to improve the clinical outcome in procedures treating trauma, fracture non-unions, spinal fusion, osteonecrosis, and segmental bone osteotomies such as those created upon tumor removal. Tissue engineering is a promising strategy to promote bone regeneration. However, the general approach in bone tissue engineering to directly stimulate bone formation through osteogenesis has been largely unsuccessful. In this proposal we approach bone regeneration through a cartilage intermediate. This process, called endochondral ossification, is the normal developmental mechanism for formation of long bones, and is the pathway through which the majority of fractures heal. I hypothesize that bone regeneration through a chondrogenic intermediate will produce a neotissue that resembles the native bone in both form and function. To test this hypothesis I will compare bone regeneration from a cartilage graft to the gold-standard bone graft technique in a critically sized murine bone defect. In support of this approach, I have preliminary data demonstrating that a cartilage graft containing hypertrophic chondrocytes promotes a well-vascularized and integrated bone regenerate. In addition to evaluating the quality of bone regenerated by a cartilage graft versus bone graft, I will determine the mechanism through which repair occurs. According to my hypothesis, bone regeneration will occur through the process of endochondral ossification, resulting in apoptosis of hypertrophic chondrocytes and producing a bone regenerate that is host derived. However, preliminary data indicate that donor cartilage is contributing to the bone regenerate through an unresolved mechanism. I will use genetic and cell labeling techniques to trace the cell phenotype throughout this repair process to evaluate how the cartilage heals large bone defects. The second aim of this research proposal is to translate the concept of promoting bone regeneration through endochondral ossification into a clinically viable technology. To accomplish this I will design biologically modified synthetic scaffolds that promote formation of hypertrophic cartilage from mesenchymal stem cells (MSCs). Scaffold will be designed with variable degradation rates tuned to the process of endochondral ossification to optimize bone regeneration in vivo. In earlier studies I have characterized hypertrophic maturation of MSCs in tissue-engineered scaffolds and developed a MMP-7 bioresponsive system tuned to chondrogenesis. Together these aims address an important clinical problem with a translatable technology capable of improving current bone regeneration techniques. Furthermore this project was specifically designed to meet my long-term career objective related to musculoskeletal regeneration by utilizing multipotent progenitor cells and bioresponsive scaffolds to recapitulate normal development and/or repair mechanisms in clinically relevant in vivo models. PUBLIC HEALTH RELEVANCE: Presently there is no adequate bone graft technology that allows for correction of large segmental defects that occur in response to trauma, gunshot and artillery wounds, and that occur upon tumor removal. The success of this project may have widespread and immediate impact on human health by developing a cartilage template that will promote bone regeneration through the process of endochondral ossification. This project will investigate the in vivo molecular mechanism and quality of bone regeneration from a cartilage graft in the first aim, and then develop a tissue engineering strategy that uses a biologically modified scaffold to promote cartilage formation from mesenchymal stem cells in the second aim.

描述（由申请人提供）：目前可用于治疗大节段缺损的骨移植技术通常会产生血管供应不良和宿主整合不良的替代组织，从而导致与骨坏死或移位相关的临床失败。因此，对于改善治疗创伤、骨折不愈合、脊柱融合、骨坏死和节段骨截骨术（例如肿瘤切除后产生的截骨术）的手术的临床结果存在显着的未满足需求。组织工程是促进骨再生的一种有前途的策略。然而，骨组织工程中通过成骨直接刺激骨形成的一般方法基本上不成功。在这个提案中，我们通过软骨中间体实现骨再生。这一过程称为软骨内骨化，是长骨形成的正常发育机制，也是大多数骨折愈合的途径。我假设通过软骨形成中间体进行的骨再生将产生在形式和功能上类似于天然骨的新组织。为了验证这一假设，我将在临界尺寸的小鼠骨缺损中比较软骨移植的骨再生与金标准骨移植技术。为了支持这种方法，我有初步数据表明，含有肥大软骨细胞的软骨移植物可以促进血管化和整合的骨再生。除了评估软骨移植与骨移植再生骨的质量之外，我还将确定修复发生的机制。根据我的假设，骨再生将通过软骨内骨化过程发生，导致肥大软骨细胞凋亡并产生源自宿主的骨再生。然而，初步数据表明，供体软骨通过一种尚未解决的机制促进骨骼再生。我将使用遗传和细胞标记技术来追踪整个修复过程中的细胞表型，以评估软骨如何治愈大骨缺损。该研究计划的第二个目标是将通过软骨内骨化促进骨再生的概念转化为临床可行的技术。为了实现这一目标，我将设计经过生物修饰的合成支架，促进间充质干细胞（MSC）形成肥大软骨。支架将设计成具有可变降解率，以适应软骨内骨化过程，以优化体内骨再生。在早期的研究中，我表征了组织工程支架中 MSC 的肥大成熟，并开发了一种针对软骨形成调整的 MMP-7 生物反应系统。这些目标共同通过能够改进当前骨再生技术的可转化技术解决了一个重要的临床问题。此外，该项目是专门为满足我与肌肉骨骼再生相关的长期职业目标而设计的，通过利用多能祖细胞和生物响应支架来重现临床相关体内模型中的正常发育和/或修复机制。 公众健康相关性：目前还没有足够的骨移植技术来纠正因创伤、枪伤和炮伤以及肿瘤切除时发生的大节段缺损。该项目的成功可能会通过开发一种软​​骨模板来对人类健康产生广泛而直接的影响，该软骨模板将通过软骨内骨化过程促进骨再生。该项目的第一个目标是研究软骨移植骨再生的体内分子机制和质量，然后开发一种组织工程策略，使用生物修饰的支架促进间充质干细胞形成软骨。