Rapid 3D Bioprinting of Cell-Laden Neurotrophic Factory Gradient Conduit for Neural Tissue Regeneration and Functional Recovery

项目摘要 临床上需要一种有效的神经引导导管来治疗长间隙周围神经损伤。许多 研究已经探索了不同的材料和活性线索来引导神经再生，并取得了一些成功。 然而，没有一种方法显示出与金标准自体移植物相当或更好的功能恢复。 自体移植物需要额外的手术来移除患者的感觉神经，例如腓肠神经 这会导致感觉丧失此外，自体移植物不足以恢复患者的功能。 臂丛神经和坐骨神经大面积损伤我们假设， 需要物理、细胞和生化指导线索来实现功能恢复， 与自体移植物相当或更好。3D打印的导管可以设计成与导管的尺寸匹配。 针对患者的具体护理的损伤缺陷。快速投影，图像引导，直接打印（RaPID）能够 产生具有数秒至数分钟量级的微尺度特征的真3D细胞负载水凝胶构建体。 雪旺细胞通过释放神经营养因子， 维持并引导再生轴突。GDNF是一种神经营养因子，其在运动神经中的作用引起了人们的高度兴趣。 神经元再生作者计划首先通过基因工程改造雪旺细胞来解决这一假设 过表达GDNF，然后通过光化学将它们沿着3D打印的多- 在一个实施方案中，所述方法包括以密度梯度模式的微通道导管来产生持续产生的可溶性GDNF梯度。 一旦得到验证，作者计划在小鼠坐骨神经损伤模型中进行体内研究，以获得 协同导管相对于脱细胞导管和自体移植物的功能恢复功效。这项建议 阐述了NINDS的使命，即减少每个年龄组和年龄段的神经系统疾病负担 通过开发一种针对患者的管道，具有增强功能恢复的协同提示， 在PNI之后。

PROJECT SUMMARY There is a clinical need for an effective neural guidance conduit to treat long gap peripheral nerve injuries. Many studies have explored different materials and active cues to guide neural regeneration, with some success. However, none have demonstrated a comparable or better functional recovery than the gold standard autograft. An autograft requires an additional surgery to remove a sensory nerve such as the sural nerve from the patient which can lead to loss of sensation. Additionally, an autograft is not a sufficient treatment to restore function for large gap injuries to the brachial plexus and sciatic nerves. We hypothesize that a synergistic combination of physical, cellular, and biochemical guidance cues is required to achieve robust functional recover on par or better than that provided by an autograft. A 3D printed conduit can be designed to match the size of the injury defect for patient specific care. Rapid Projection, Image-guided, Direct Printing (RaPID) is capable of producing true-3D cell-laden hydrogel constructs with microscale features on the order of seconds to minutes. Schwann cells play a key role in endogenous peripheral nerve regeneration by releasing neurotrophic factors to both sustain and guide the regenerating axons. GDNF is a neurotrophic factor of high interest for its role in motor neuron regeneration. The authors plan to address the hypothesis by first genetically engineering Schwann cells to overexpress GDNF, then anchoring them via photochemistry along the length of the 3D-printed multi- microchannel conduit in a density gradient pattern to create a persistently generated soluble GDNF gradient. Once validated, the authors plan to run an in vivo study in a murine sciatic nerve injury model to access the functional recovery efficacy of the synergistic conduit versus the acellular conduit and autograft. This proposal addresses the NINDS mission of reducing the burden of neurological disease for every age group and segment of society by developing a tailored-to-patient conduit with synergistic cues for enhanced restoration of function after a PNI.