Understanding revascularization and repair of cranial bone grafts via intravital imaging

通过活体成像了解颅骨移植物的血运重建和修复

• 批准号: 9165637
• 负责人: Edward Bernard Brown
• 金额: $ 23.72万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2018-08-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9165637
• 关键词: 4D Imaging; Allografting; Animal Model; Animals; Autologous Transplantation; Blood Vessels; Bone Marrow; Bone Regeneration; Bone Tissue; Bone Transplantation; Cell Survival; Cell Therapy; Cells; Cephalic; Cicatrix; Complex; Coupling; Data; Defect; Dependency; Development; Engineering; Engraftment; FDA approved; Future; Glycocalyx; Goals; HIF1A gene; Healed; Histology; Hypoxia; Hypoxia Pathway; Image Analysis; Imagery; Isogenic transplantation; Knowledge; Laser Scanning Microscopy; Life; Literature; Measurement; Mesenchymal Stem Cells; Modeling; Molecular; Monitor; Mus; Natural regeneration; Osteoblasts; Osteocytes; Osteogenesis; Outcome; Oxygen; Pathway interactions; Pharmaceutical Preparations; Pharmacologic Substance; Phosphorescent Assays; Platinum; Population; Porphyrins; Process; Resolution; Role; Scanning; Seeds; Signal Transduction; Site; Stem cells; Technology; Testing; Therapeutic; Therapeutic Intervention; Time; Tissue Grafts; Tissues; Transgenic Animals; Transplantation; Vascularization; Wild Type Mouse; allogenic bone transplantation; angiogenesis; base; bone; bone healing; graft healing; healing; hypoxia inducible factor 1; in vivo; innovation; insight; intravital imaging; microCT; mouse model; nanoprobe; neovascularization; novel; osteogenic; osteoprogenitor cell; overexpression; postnatal; progenitor; real time model; reconstruction; repaired; sensor; spatiotemporal; tool

Revascularization is a key determining factor in bone graft healing and repair. Autografts are vastly superior to allografts and synthetic bone grafts largely due to the fact that autografts can be rapidly revascularized and form new bone whereas allografts cannot. While vascularization of bone tissue has been increasingly recognized as a key factor in repair and reconstruction, our understanding of bone graft vascularization in bone transplantation has been limited to histological observations described in the early 70s and 80s. These descriptions are often restricted by dependency on histology which prohibits three-dimensional and spatiotemporal analyses of vascularization of the grafted bone. We have recently established a cranial bone window chamber model which allows high resolution, four-dimensional imaging and analyses of bone defect healing over a period of months using multiphoton laser scanning microscopy (MPLSM). By transplanting allograft and autograft bone into this windowed bone defect model, we were able to track the revascularization process and demonstrate the fundamental differences between allografts and autografts in living animals. The goal of our current proposal is to utilize this novel intravital imaging approach combined with transgenic animal models to gain a better understanding of the vascularization mechanisms of bone graft transplantation. Based on our preliminary date and recent literature on the key role of hypoxia-inducible factor 1- alpha (HIF-1α) in oxygen sensing and coupling of osteogenesis and angiogenesis, two complementary Aims are proposed. Aim 1 will examine the key role of the HIF-1 pathway in revascularization and repair by transplantation of a HIF-1 deficient or over-activated live bone isograft into a cranial defect window chamber model. Aim 2 will determine the effects of engraftment of MSCs with enhanced HIF-1 signaling on bone allograft revascularization and repair. A novel oxygen sensor, which allows quantitative measurements of oxygen tension simultaneously with osteogenesis and angiogenesis in vivo will be established. The completion of our current project will enhance our knowledge of graft healing and revascularization and further offer rationales and strategies to augment the efficacy of future cell-based therapy aimed at enhancing bone repair and regeneration. Understanding the complex role of hypoxia and its master regulators in bone graft revascularization and bone healing will further aid in the development of novel pharmaceutical agents that can redress the detrimental outcomes often seen in repair and scarring of bone allograft healing.

血运重建是骨移植愈合和修复的关键决定因素。自体移植物 大大上级同种异体移植物和合成骨移植物，这主要是由于自体移植物可以 可以迅速地再血管化并形成新骨，而同种异体移植物不能。当血管化 越来越多的人认识到骨组织是修复和重建的关键因素， 对骨移植中骨移植物血管化的理解仅限于 70年代和80年代早期描述的组织学观察。这些描述往往 受组织学的限制，组织学禁止三维和时空 移植骨血管化分析。我们最近发现了一块颅骨 窗口室模型，允许高分辨率，四维成像和分析， 使用多光子激光扫描显微镜观察骨缺损在数月内的愈合情况 （MPLSM）。通过将同种异体骨和自体骨移植到这种开窗骨缺损模型中， 我们能够追踪血运重建的过程， 活体动物同种异体移植物和自体移植物之间的差异。我们当前提案的目标是 是利用这种新的活体成像方法与转基因动物模型相结合， 更好地了解骨移植物的血管化机制。 根据我们的初步数据和最近关于缺氧诱导因子1的关键作用的文献， HIF-1α在氧传感和骨生成与血管生成的偶联中的作用， 提出了补充目标。目的1将研究HIF-1通路在 通过移植HIF-1缺陷或过度活化的活骨进行血管再生和修复 同种异体移植到颅骨缺损窗室模型中。目标2将决定 植入具有增强的HIF-1信号传导的MSC对骨移植物血管重建和 修复.一种新型的氧传感器，它允许定量测量氧张力 同时在体内建立骨生成和血管生成。完成 我们目前的项目将提高我们的知识移植愈合和血运重建， 进一步提供了理论基础和策略，以提高未来基于细胞的治疗的疗效， 促进骨骼修复和再生了解缺氧的复杂作用及其 骨移植物血管再生和骨愈合中的主要调节剂将进一步帮助 开发新的药物制剂，可以纠正有害的结果往往 在同种异体骨愈合的修复和瘢痕形成中可见。