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

项目总结 临床上需要一种有效的神经引导管道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跃的线索来指导神经再生，并取得了一些成功。 然而，没有一种植骨表现出与黄金标准自体移植相当或更好的功能恢复。 自体移植需要额外的手术来移除患者的感觉神经，如腓肠神经。 这可能会导致感觉丧失。此外，自体移植不是恢复功能的充分治疗。 臂丛和坐骨神经的大间隙损伤。我们假设，一个协同的组合 需要物理、细胞和生化指导线索才能实现强大的功能恢复 与自体移植物相当或更好。3D打印管道可以设计为与 对损伤缺陷进行患者特殊护理。快速投影、图像引导、直接打印(RAPID)能够 生产真正的3D细胞负载水凝胶结构，具有几秒钟到几分钟量级的微尺度特征。 雪旺细胞通过释放神经营养因子在内源性周围神经再生中发挥关键作用 既支持和引导再生的轴突。GDNF是一种神经营养因子，因其在运动中的作用而备受关注 神经元再生。作者计划通过首先对雪旺细胞进行基因工程来解决这一假设 过表达GDNF，然后通过光化学沿着3D打印的多个 密度梯度图案中的微通道导管，以产生持续产生的可溶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 与脱细胞导管和自体移植相比，协同导管的功能恢复效果。这项建议 NINDS的使命是减轻每个年龄段和年龄段的神经系统疾病的负担 通过开发一种为患者量身定做的管道来促进功能恢复，并提供协同提示 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.