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.

项目概要/摘要 周围神经间隙损伤的重建仍然在临床上构成挑战，因为它们 显着的长期功能发病率。已开发出多种手术方法来促进 神经再生穿过有间隙的受损神经。在临床上，自体神经移植被认为是 由于其促进神经再生的卓越能力，因此成为治疗神经间隙的护理标准。 然而，自体神经移植的使用受到其可用性、手术时间增加、神经损失的限制。 神经功能丧失和供体部位发病率。已提出脱细胞神经同种异体移植物（ANA） 由于其具有促进再生的能力，可作为自体移植物修复神经间隙的临床替代方案 穿过短间隙 (< 3 cm)。 ANA 是同种异体神经，经过化学处理以去除细胞， 降低免疫原性，同时维持细胞外基质 (ECM)，使细胞能够迁移到 ANA 和随后的神经再生。然而，与自体移植不同，ANA 不支持再生 跨越长缺陷 (> 3 cm)。长 ANA 不促进再生或再生不良的原因 还没有完全理解。先前的研究已经证明炎症细胞的关键作用， 例如巨噬细胞和T细胞，在调节和促进神经再生的早期阶段 ANA（术后 4 周前）。具体来说，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的表达增加以及 神经再生后期（4-和8-之间）长ANA中的血管形态 手术后几周）。促炎细胞因子表达的增加和 血管的形态发生在血管生成发生并且轴突开始迁移到 ANA。这些变化表明促炎环境在长 ANA 内形成 神经再生的后期阶段，这与血管和血管形态的变化相关 有髓轴突数量减少。我们假设长期慢性炎症状态 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 表征和比较神经后期发展的炎症微环境 长 ANA 的再生与再生短 ANA 和自体移植物中的微环境的关系。这 项目还探索了使用药物干预来减少长 ANA 炎症的效果， 关于轴突再生。这项研究的一个组成部分是确定促进亲细胞亚群的细胞亚群。 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 神经再生的疗法的特定分子靶标。