Cell-integrated microfibers for improved nerve regeneration

细胞集成微纤维可改善神经再生

• 批准号: 8922542
• 负责人: JOSEPH M. COREY
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8922542
• 关键词: Amoeba genus; Autologous; Autologous Transplantation; Axon; Bacteria; Biocompatible Materials; Biomimetics; Caliber; Cell Density; Cell Proliferation; Cell Survival; Cells; Complex; Cues; Development; Disadvantaged; Distal; Encapsulated; Engineering; Extracellular Matrix; Fiber; Glycoproteins; Goals; Growth; Histocompatibility Testing; Hybrids; Implant; Inferior; Injury; Lead; Left; Length; Life; Mammalian Cell; Methods; Modeling; Morphology; Natural regeneration; Nerve; Nerve Endings; Nerve Regeneration; Nervous system structure; Neurites; Neurons; Operative Surgical Procedures; Outcome; Patients; Penetration; Peripheral Nerves; Polymers; Porosity; Problem Solving; Process; Publishing; Rattus; Recovery; Schwann Cells; Side; Staging; Supporting Cell; Techniques; Technology; Testing; Tissue Engineering; Tissues; Transplantation; Trauma; Traumatic injury; Yeasts; axon regeneration; cell type; design; experience; implantation; improved; in vivo; nanofabrication; nanofiber; nerve gap; nerve injury; novel; peripheral nerve regeneration; poly(lactide); prototype; public health relevance; repaired; scaffold; sciatic nerve; standard of care; tool

 DESCRIPTION (provided by applicant): After traumatic injury to peripheral nerves, recovery is poor. The current standard of care is coaptation of the proximal and distal ends of the nerve, or if the gap between the two ends is too large, the use of autologous nerve grafts. The insufficiencies of donor nerve in both diameter and number of available nerves has led to the development of nerve guidance channels, engineered constructs including both artificial and natural materials. However, most designs still underperform compared to autografts because they lack Schwann cells, the glial, or support cells of peripheral nerve. These cells deliver growth factors, substrate glycoproteins, and topographical cues that potentiate axon regeneration following injury, and nerve guidance channels that possess Schwann cells outperform those that lack them. One of the recent advances in guidance channel design is the incorporation of longitudinally aligned, electrospun fibers on the cell-length scale that direct the growth of regenerating axons by contact guidance. Electrospinning is a method of fabricating nano- and microfibers that resemble native extracellular matrix, and the development of these biomimetic constructs has accelerated advances in engineering of multiple tissue types. Combining the directional guidance of micro- and nanofibers by pre-seeding them with Schwann cells seems a straightforward strategy, but electrospun fiber matrices are disadvantaged by small pore sizes that limit the depth of cell penetration to only one or two cell diameters, leaving much of the electrospun matrix devoid of cells. Here we propose solving this problem by developing a means to integrate Schwann cells into fibers produced by a process similar to electrospinning, called jetting. Jetting eliminates th high forces that reduce cell viability when electrospinning cells into fibers. If successful, this process would disperse cells evenly throughout an aligned-fiber matrix. The goal of this project is to provide scientific evidence needed to allow for the rational development of microfibers with integrated Schwann cells. In specific aim 1, we fabricate and test a novel side-by-side biphasic fiber design. One layer encapsulates Schwann cells as the fiber is made and rapidly degrades to release them. The second layer, produced simultaneously in this biphasic jetting process, degrades much more slowly and remains to provide a topographical cue to the released cells. Fiber morphology, diameter, degradation, and cell viability and proliferation are tested at all stages of development. In aim 2, we test the ability of scaffolds containing prototype fibers with integrated Schwann cells to improve regeneration in a sciatic nerve gap injury model. After 1.5 or 4 months have elapsed following implantation, the number of transplanted versus native Schwann cells in each graft is determined. Then the number of axons and the distance they have grown in is assessed and compared to grafts containing both autologous nerve and aligned electrospun fibers. It is hoped that this project will serve to develop an enabling technology toward the improvement regeneration in the nervous system.

 描述（由申请人提供）： 外周神经受伤后，恢复较差。当前的护理标准是神经近端和不同末端的仪式，或者如果两端之间的间隙太大，则使用自体神经移植物。直径和可用神经数量的供体神经的不足导致了神经引导渠道的发展，包括人工和天然材料在内的工程结构。然而，与自体移植相比，大多数设计仍然不足，因为它们缺乏雪旺细胞，周围神经的神经胶质或支持细胞。这些细胞提供生长因子，底物糖蛋白以及损伤后潜在轴突再生的地形线索，而神经引导通道具有Schwann细胞的表现优于缺乏它们的细胞。指导通道设计的最新进展之一是将纵向排列的电纺纤维掺入细胞长度尺度上，该纤维通过接触指南指导再生轴突的生长。静电纺丝是一种制造类似于天然细胞外基质的纳米和微纤维的方法，这些仿生构建体的发展已加速了多种组织类型的工程学进步。将微纤维和纳米纤维的定向引导结合起来，通过将它们预先与Schwann细胞进行预种，这似乎是一种直接的策略，但是电纺纤维材料材料被小孔径限制在细胞渗透深度仅至一个或两个细胞直径的小孔径中，而造成细胞的大量细胞。在这里，我们提出了通过开发一种将雪旺细胞整合到类似于静电纺丝的过程中的纤维的方法来解决此问题的方法。喷射消除了静电纺丝成纤维时降低细胞活力的高力。如果成功，此过程将在整个对齐的纤维基质中均匀分散细胞。该项目的目的是提供所需的科学证据，以允许具有综合Schwann细胞的微纤维的合理发展。在特定的目标1中，我们制造并测试了新型的并排双相纤维设计。一层将Schwann细胞封装在制造纤维并迅速降解以释放它们时。第二层在这个双相喷射过程中很容易产生，降解得更慢，并且为释放的细胞提供了地形提示。纤维形态，直径，降解和细胞活力和增殖在发育的各个阶段都经过测试。在AIM 2中，我们测试了含有具有集成Schwann细胞原型纤维的脚手架的能力，以改善坐骨神经神经间隙损伤模型中的再生。植入后经过1.5或4个月后，确定每个移植物中移植的天然schwann细胞的数量。然后，评估了轴突的数量及其成长的距离，并将其与含有自体神经和对齐电纺纤维的移植物进行了比较。希望该项目将有助于开发一种促进技术的技术来改善神经系统的再生。