The role of the inflammatory microenvironment in Acellular Nerve Allografts (ANAs) repairing nerve gaps

炎症微环境在无细胞神经同种异体移植物（ANA）修复神经间隙中的作用

• 批准号: 10678384
• 负责人: Jesús Alberto Acevedo Cintrón
• 金额: $ 3.36万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10678384
• 关键词: Affect; Allogenic; Allografting; Autologous Transplantation; Axon; Biomedical Engineering; Blood Vessels; Caring; Cells; Chemicals; Chronic; Clinic; Clinical; Data; Defect; Detergents; Expenditure; Extracellular Matrix; FK506; Fellowship; Gene Expression; Goals; Harvest; Immunology; Immunosuppressive Agents; Inflammation; Inflammatory; Inflammatory Response; Injury; Intervention; Knowledge; Learning; Length; Macrophage; Measures; Modeling; Modification; Molecular Target; Morbidity - disease rate; Morphology; Natural regeneration; Nerve; Nerve Regeneration; Neurobiology; Operative Surgical Procedures; Patients; Peripheral Nerves; Peripheral nerve injury; Process; Quality of life; Rattus; Recovery of Function; Research; Role; Scientist; Site; T-Lymphocyte; Tacrolimus; Techniques; Testing; Time; Training; Translating; Trauma; United States; angiogenesis; axon regeneration; cell motility; cytokine; experience; immunogenicity; inflammatory marker; inflammatory milieu; inflammatory modulation; migration; myelination; nerve autograft; nerve damage; nerve gap; nerve injury; nerve repair; novel; pharmacologic; reconstruction; regeneration potential; regenerative; repaired; sciatic nerve; single-cell RNA sequencing; standard of care; therapy development

PROJECT SUMMARY/ABSTRACT Reconstruction of peripheral nerve gap injuries continues to pose a challenge in the clinic due to their significant long-term functional morbidity. Multiple surgical approaches have been developed to promote nerve regeneration across a damaged nerve with a gap. In the clinic, nerve autografts are considered the standard of care in treating nerve gaps due to their superior capacity in promoting nerve regeneration. However, the use of nerve autografts is limited by their availability, increased surgery time, loss of nerve function from the lost nerve and donor site morbidity. Acellular nerve allografts (ANAs) have been proposed as a clinical alternative to autografts in repairing nerve gaps due to their capability in promoting regeneration across short gaps (< 3 cm). ANAs are allogenic nerves that are chemically processed to remove the cells, reducing immunogenicity, while maintaining the extracellular matrix (ECM) that will allow cell migration into the ANA and subsequent nerve regeneration. However, unlike autografts, ANAs do not support regeneration across long defects (> 3 cm). The reason why long ANAs do not promote regeneration or regenerate poorly is not completely understood. Previous studies have demonstrated the critical role of inflammatory cells, such as macrophages and T cells, in regulating and promoting the early stages of nerve regeneration in ANAs (before 4 weeks post-surgery). Specifically, macrophages will promote angiogenesis and T cells will promote axonal myelination. However, when compared to short ANAs capable of robust regeneration, preliminary data shows an increase in the expression of pro-inflammatory cytokines and changes in the morphology of blood vessels in long ANAs at the later stages of nerve regeneration (between 4- and 8- weeks post-surgery). The increase in the expression of pro-inflammatory cytokines and the changes in the morphology of blood vessels happen after angiogenesis has occurred and axons have started migrating into the ANAs. These changes suggest that a pro-inflammatory environment develops inside long ANAs in the later stages of nerve regeneration, and this correlates with changes in the morphology of blood vessels and a decrease in the number of myelinated axons. We hypothesize the state of chronic inflammation in long ANAs is disrupting the regenerative microenvironment in long ANAs. In brief, the proposed research aims to characterize and compare the inflammatory microenvironment that develops in the later stages of nerve regeneration in long ANAs with the microenvironment in the regenerated short ANAs and autografts. This project also explores the effect of reducing inflammation in long ANAs, using a pharmacological intervention, on axonal regeneration. An integral part of this study is to identify the cell subpopulations promoting the pro- inflammatory microenvironment in long ANAs. An in-depth analysis of these cell subpopulations may provide specific molecular targets used to develop therapies aimed to promote nerve regeneration in long ANAs.

项目总结/摘要 周围神经间隙损伤的重建在临床上仍然是一个挑战，因为它们 长期功能性疾病。已经开发了多种手术方法来促进 神经再生穿过受损的神经间隙。在临床上，自体神经移植被认为是 由于其在促进神经再生方面的上级能力，因此是治疗神经间隙的护理标准。 然而，自体神经移植物的使用受到其可获得性、手术时间增加、神经丢失等因素的限制。 失去的神经和供体部位的发病率。脱细胞同种异体神经移植物（ANAs）已被提出 由于其促进再生的能力，在修复神经缺损中作为自体移植物的临床替代物 穿过短间隙（< 3 cm）。ANA是同种异体神经，经过化学处理去除细胞， 降低免疫原性，同时维持细胞外基质（ECM），这将允许细胞迁移到 ANA和随后的神经再生。然而，与自体移植物不同，ANA不支持再生 跨越长缺陷（> 3cm）。长ANA不能促进再生或再生不良的原因 还没有完全被理解。以前的研究已经证明了炎症细胞的关键作用， 如巨噬细胞和T细胞，在调节和促进神经再生的早期阶段， ANA（术后4周前）。具体地说，巨噬细胞将促进血管生成，T细胞将 促进轴突髓鞘形成。然而，与能够稳健再生的短ANA相比， 初步数据显示促炎细胞因子表达增加， 在神经再生的后期阶段（4- 8- 10周之间），长ANA中的血管形态 手术后数周）。促炎性细胞因子表达的增加和细胞因子水平的变化， 血管形态发生在血管生成发生之后，轴突开始迁移到 的ANA。这些变化表明，促炎环境的发展内长ANA中， 神经再生的后期阶段，这与血管形态的变化有关， 有髓轴突数量的减少。我们假设慢性炎症的状态在长期 ANA正在破坏长ANA中的再生微环境。简而言之，拟议的研究目标 表征和比较在神经损伤后期发展的炎症微环境， 长ANA中的再生与再生的短ANA和自体移植物中的微环境。这 该项目还探讨了减少炎症的影响，在长ANA，使用药物干预， 轴突再生本研究的一个组成部分是鉴定促进促增殖的细胞亚群， 长ANA中的炎症微环境。对这些细胞亚群的深入分析可以提供 用于开发旨在促进长ANA中神经再生的疗法的特定分子靶点。