Therapeutic potential of systemic and localized zinc delivery for modulating fracture repair

全身和局部锌输送调节骨折修复的治疗潜力

• 批准号: 10648863
• 负责人: Michael William Hast
• 金额: $ 16.25万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-18 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10648863
• 关键词: American; Animals; Apoptosis; Award; Biocompatible Materials; Biological Assay; Biology; Bone Regeneration; Bone callus; Calcium; Cell Culture Techniques; Cell Death; Cells; Cessation of life; Complex; Data; Deposition; Development; Devices; Diet; Disease; Evolution; Excretory function; Femur; Foundations; Fracture; Future; Histology; Homeostasis; Human; Hydrogels; Immunohistochemistry; Impairment; Implant; In Vitro; Injury; Intramedullary Nailing; Link; Long-Term Care Nursing; Mentors; Mesenchymal Stem Cells; Metals; Microscopy; Mission; Modeling; Osteoblasts; Osteogenesis; Osteoporosis; Osteotomy; Pennsylvania; Persons; Pilot Projects; Play; Polishes; Polymers; Positioning Attribute; Proliferating; Rattus; Research; Role; Series; Speed; Sprague-Dawley Rats; Stains; Surface; Testing; Therapeutic; Titanium; Trauma; United States National Institutes of Health; Universities; Weight-Bearing state; X-Ray Computed Tomography; Zinc; biodegradable polymer; biomechanical test; bone; bone fracture repair; bone healing; bone mass; bone preservation; bone repair; cell behavior; data submission; experimental study; fluorexon; healing; implantation; improved; in vitro Model; in vivo; mechanical load; mechanical stimulus; mechanotransduction; meter; microCT; premature; reconstruction; regenerative cell; response; skills training; stem cell fate; synergism; trafficking; transcription factor; uptake

Bone fractures are common injuries that impact millions of people each year, and poorly healed fractures cause impaired mobility, long-term nursing care, or even premature death. It is known that controlled mechanical loading can improve the quality and speed of fracture repair, but our understanding of mechano- therapeutics is still underdeveloped. Recent research has indicated that zinc may play a fundamental role in the evolution of fracture repair. Zinc is known to stimulate new bone formation, preserve bone mass, and regulate apoptosis. Importantly, intracellular zinc homeostasis must be carefully coordinated to regulate uptake, excretion, and intracellular storage/trafficking. It is believed that zinc may be mechanosensitive; however, the relationships between mechanical loading, zinc homeostasis, and fracture healing remain unclear. This project will generate preliminary data regarding the relationships between mechanotransduction in regenerative cells and establish links between mechanical load transfer and intracellular Zinc homeostasis in bone fractures. Our global hypothesis is that the combination of zinc with mechanical loading will lead to synergistic bone healing responses. In Aim 1, we will extend our existing K25 study with an in vivo rat femoral osteotomy model and determine changes in bone healing caused by zinc delivery and load transfer. Sprague Dawley rats will undergo femoral osteotomy and reconstruction. Mechanical loads across the callus will be controlled with either rigid locking plates (0-3% strain, low load across fracture) or more compliant locking plates (10-15% strain, high load across fracture). Zinc levels in animals will be manipulated systemically (through diet) and locally (implantation of a non-loadbearing intramedullary nail). We hypothesize that the combinatory application of mechanical loads and zinc delivery will lead to synergistic improvements in bone healing that are demonstrated by faster and more robust development of callus. Changes in bone healing will be quantified with micro-CT imaging, biomechanical testing, histology, and qPCR. In Aim 2, we will define the causal relationships between zinc delivery, load transfer, zinc storage/trafficking, and osteoblast formation in an in vitro cell culture model. Here, we will use cell culture techniques to examine the fate of human mesenchymal stem cells. We hypothesize that Zinc-rich cells plated on stiff, smooth surfaces will elicit improved osteoblastic proliferation and superior calcium matrix formation. These experiments will yield fundamental new understanding into the mechanisms by which cells receive and respond to mechanical stimuli and provide foundational data for long-term development of Zinc-augmented mechano-therapeutics. Characterizing these relationships may have immense implications for cellular mechanobiology and development of mechano-therapeutic approaches for bone regeneration and repair.

骨折是每年影响数百万人的常见伤害，而且骨折愈合不良 导致行动不便、长期护理，甚至过早死亡。据了解，受控 机械加载可以提高骨折修复的质量和速度，但我们对机械加载的理解 治疗学仍不发达。最近的研究表明，锌可能在 骨折修复的演变。众所周知，锌可以刺激新骨形成，保持骨量，并 调节细胞凋亡。重要的是，必须仔细协调细胞内锌稳态以调节 摄取、排泄和细胞内储存/运输。人们相信锌可能是机械敏感的； 然而，机械负荷、锌稳态和骨折愈合之间的关系仍然存在 不清楚。该项目将生成有关机械转导之间关系的初步数据 在再生细胞中，并在机械负荷转移和细胞内锌稳态之间建立联系 骨折。我们的总体假设是，锌与机械载荷的结合将导致 协同骨愈合反应。在目标 1 中，我们将利用体内大鼠股骨来扩展我们现有的 K25 研究 截骨模型并确定由锌输送和负荷转移引起的骨愈合变化。斯普拉格 Dawley 大鼠将接受股骨截骨术和重建术。愈伤组织上的机械载荷将为 通过刚性锁定板（0-3% 应变、断裂负载低）或更柔顺的锁定进行控制 板（10-15% 应变，断裂处高负载）。动物体内的锌含量将受到系统控制 （通过饮食）和局部（植入非承重髓内钉）。我们假设 机械负荷和锌输送的组合应用将导致骨骼的协同改善 愈伤组织生长得更快、更健壮，证明愈合。骨骼愈合的变化将 通过显微 CT 成像、生物力学测试、组织学和 qPCR 进行量化。在目标 2 中，我们将定义 锌输送、负荷转移、锌储存/运输和成骨细胞形成之间的因果关系 体外细胞培养模型。在这里，我们将利用细胞培养技术来检验人类的命运 间充质干细胞。我们假设将富锌细胞镀在坚硬、光滑的表面上会引起 改善成骨细胞增殖和更好的钙基质形成。这些实验将产生 对细胞接收和响应机械刺激的机制有了全新的认识 并为锌增强机械疗法的长期发展提供基础数据。 表征这些关系可能对细胞力学生物学和 骨再生和修复的机械治疗方法的发展。