Micro engineered 3D constructs for CNS repair

用于中枢神经系统修复的微工程 3D 结构

• 批准号: BB/G004706/1
• 负责人: Susan Barnett
• 金额: $ 73.02万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FG004706%2F1
• 关键词: Micro; engineered; 3D; constructs; CNS

Spinal cord injury often leads to a paralysis of parts of the body (i.e. the late actor Chris Reeves 'Superman') - which can be in most severe cases affect all four limbs, and in others just the bladder, the legs and lower parts of the body etc. This is due to the direct or indirect damage to the nerve fibres (known as axons) running from the brain along the spinal cord, and those carrying sensory information from the periphery back to the brain. After the injury the area damaged will fill with non-functional scar tissue. Unfortunately there is very little recovery after injury and no restoration of function - even over many years. The biological aspects of spinal cord repair after injury is a complex problem that is not completely understood and is actively being investigated. Leading neurosurgeons agree that future treatment envisaged for the repair of spinal cord injury will be a combination of a cellular transplant with pharmacological intervention. Popular candidates for transplantation are support cells or glia (astroglia, olfactory ensheathing cells) that normally envelope and guide regenerating nerve processes. It is hoped that these cells will aid axonal regeneration across the graft through the site of the scar into normal CNS tissue. As the scar environment is inhibitory to axonal outgrowth due to the presence of many inhibitory molecules (a molecule involved in this is even called nogo!) intervention with drugs is necessary to either overcome inhibitory signals or to remove the inhibitory molecules Our recent data on cellular transplantation using olfactory glia has shown that they can support the ingrowth of many axons, although very few if any appear to exit the graft. Anatomical examination of the grafts gives an impression that the axons are wrapped by olfactory glia but there is no alignment of these axons or order within the graft. It is clear that CNS repair is a complex process and a single treatment like glial cell transplantation is not sufficient for restoring spinal cord function. Within this grant we intend to develop a scaffold based guidance system for axonal outgrowth. The envisaged scaffold will be a polymer with internal tiny (ca. 1/2 hair diameter wide) guidance tubes filled with transplanted glia. On the inside of these tubes we place even smaller local guidance structures. This scaffold will guide the axons and at the same time protect them from the regeneration limiting scar environment. The principles of fabrication developed for the computer industry allow us to design flat sheet of hard material (silicon) with very fine detail. In order to create 3-dimensional scaffolds we are creating polymer replicates of these structures and then roll the structured sheet up using a small device akin to a cigarette-roller. We are therefore able to make such scaffolds with very high accuracy and repeatability. By using biodegradable polymers for the scaffold the device can be left within the body slowly dissolving and being replaced with the bodies own material, all the while instructing the nerve extensions. As it is not beforehand obvious how the nerve helper cells and the extending axons interact within such an artificial environment we will investigate the cellular response in molecular detail and use the information gained to inform the construct design in a constant dialog. One example of the structural features modified, which are expected to have a significant effect on cellular survival and orientation, is the size number and distribution of perforations / which are needed to allow nutrients to enter the tube. We will also investigate which cellular transplant is best used in combination with our microstructured implant. We hope to have at the end a device and selected a cell type that together could enter in vivo testing of spinal cord injury.

脊髓损伤通常会导致身体部分瘫痪（例如，已故演员克里斯·里夫斯的《超人》）——在最严重的情况下，四肢瘫痪，还有一些人只会影响膀胱、腿和身体的下半身等。这是由于从大脑沿脊髓延伸的神经纤维（被称为轴突），以及那些将感觉信息从外围传递回大脑的神经纤维受到直接或间接的损伤。受伤后，受损部位会被无功能的疤痕组织填满。不幸的是，受伤后几乎没有恢复，即使多年后也无法恢复功能。脊髓损伤后修复的生物学方面是一个尚未完全理解的复杂问题，目前正在积极研究中。领先的神经外科医生一致认为，未来治疗脊髓损伤的设想将是细胞移植与药物干预的结合。移植的热门候选者是支持细胞或胶质细胞（星形胶质细胞，嗅鞘细胞），它们通常包裹并引导再生神经过程。人们希望这些细胞能够帮助通过疤痕部位进入正常中枢神经系统组织的移植物轴突再生。由于存在许多抑制分子（参与其中的分子甚至被称为nogo!），疤痕环境对轴突生长具有抑制作用，因此有必要进行药物干预，以克服抑制信号或去除抑制分子。我们最近使用嗅觉胶质细胞移植的数据表明，它们可以支持许多轴突的长入，尽管很少（如果有的话）似乎退出移植物。对移植物的解剖检查显示，神经轴突被嗅胶质细胞包裹，但在移植物内没有轴突排列或排列顺序。很明显，中枢神经系统的修复是一个复杂的过程，像神经胶质细胞移植这样的单一治疗不足以恢复脊髓功能。在这笔拨款中，我们打算开发一种基于支架的轴突生长引导系统。设想的支架将是一种聚合物，其内部微小（约1/2头发直径宽）的引导管充满了移植的胶质细胞。在这些管道的内部，我们放置了更小的局部引导结构。这个支架将引导轴突，同时保护它们免受限制再生的疤痕环境的影响。为计算机工业开发的制造原理使我们能够以非常精细的细节设计硬材料（硅）的平板。为了制造三维支架，我们正在制造这些结构的聚合物复制品，然后使用类似于卷烟机的小设备将结构板卷起来。因此，我们能够以非常高的精度和可重复性制造这种支架。通过使用可生物降解的聚合物作为支架，该装置可以留在体内慢慢溶解，并被人体自身的材料所取代，同时指导神经伸展。由于神经辅助细胞和延伸轴突如何在这样的人工环境中相互作用尚不清楚，我们将从分子的角度研究细胞反应，并利用所获得的信息在持续的对话中为结构设计提供信息。改变结构特征的一个例子是穿孔的大小、数量和分布，穿孔是允许营养物质进入管中所必需的，预计会对细胞的存活和方向产生重大影响。我们还将研究哪种细胞移植与我们的微结构植入物结合使用最好。我们希望最终能有一种装置和选定的细胞类型一起进入脊髓损伤的体内试验。

项目成果

The interactions of astrocytes and fibroblasts with defined pore structures in static and perfusion cultures.

• DOI: 10.1016/j.biomaterials.2010.11.046
• 发表时间: 2011-03
• 期刊: BIOMATERIALS
• 影响因子: 14
• 作者: Sun, Tao;Donoghue, Peter S.;Higginson, Jennifer R.;Gadegaard, Nikolaj;Barnett, Susan C.;Riehle, Mathis O.
• 通讯作者: Riehle, Mathis O.

A miniaturized bioreactor system for the evaluation of cell interaction with designed substrates in perfusion culture.

一种微型生物反应器系统，用于评估灌注培养中细胞与设计基质的相互作用。

• DOI: 10.1002/term.510
• 发表时间: 2012
• 期刊: Journal of tissue engineering and regenerative medicine
• 影响因子: 3.3
• 作者: Sun T