Sympathetic Function in Neural Injuries

周围神经损伤是常见的，在美国每年报告的新病例超过20万例。 只有国家。只有大约10%的人恢复了很多功能。有17,730个新的美国脊柱 每年脊髓损伤，终身成本可达每人500万美元（不包括工资损失）。神经 损伤，尤其是脊髓损伤，显著影响长期生活质量， 寻求相关残疾和疼痛的持续治疗。对贫穷最常见的解释是 功能性结果是轴突再生的缓慢和低效过程。脊髓内的轴突， 神经由运动、感觉和交感轴突组成，其在损伤后经历可塑性。一个关键 神经科学中的知识缺口是理解交感神经轴突终末在神经系统中的作用。 神经肌肉突触，与神经肌肉接头相关的交感神经轴突如何响应神经 损伤，以及它们对功能恢复或功能障碍的贡献。初步证据显示， 神经肌肉接头的交感神经支配可以调节线粒体呼吸， 生物发生、突触稳定性和肌肉强度，以及控制肌肉对运动的反应， 活动这个K01建议的首要假设是交感神经元是需要的， 正常和病理条件下神经肌肉单位的功能和代谢稳定性。我们将首先 测试交感神经活动对代谢和运动控制的必要性和充分性， 技术，生物发光光学遗传学（BL-OG）在正常的，未受伤的动物。我的研究表明， 运动和神经元活动显著增强外周轴突再生， 临床前模型中完全神经和脊髓损伤后的功能恢复。虽然 临床科学家认识到运动对促进轴突再生和代谢健康的重要性， 运动的转化潜力有许多局限性。许多患者不适合运动， 妨碍康复的合并症，神经修复手术后肢体的必要固定， 运动的剂量要求未知，患者依从性低。进一步的限制是，近70%的 脊髓损伤的人的骨骼肌是瘫痪的，并且没有电治疗的指导方针。 麻痹肌肉的诱导运动。实验证据也表明交感神经轴突再生 甚至可以通过某些类型的治疗（例如电刺激）来抑制。因此，其他目标 我们的工作是研究增加交感神经活动是否促进或抑制交感神经轴突 周围神经损伤后的再生，和2）可以挽救肌肉生物能量和运动控制缺陷 脊髓损伤后

Peripheral nerve injuries are common with more than 200,000 new cases reported each year in the United States alone. Only about 10% of these individuals regain much function. There are 17,730 new U.S. spinal cord injuries annually, and the lifetime costs can reach $5 million per person (not including lost wages). Nerve injury and especially spinal cord injury significantly impact long-term quality of life, and most injured individuals seek continued treatments for associated disabilities and pain. The most common explanation for poor functional outcomes is the slow and inefficient process of axon regeneration. Axons within the spinal cord and nerve consist of motor, sensory, and sympathetic axons, which undergo plasticity after injury. A critical knowledge gap in neuroscience is understanding the purpose of sympathetic axon terminals within the neuromuscular synapse, how sympathetic axons associated with neuromuscular junctions respond to neural injuries, and what their contribution is to functional recovery or dysfunction. Preliminary evidence suggests that the sympathetic innervation of neuromuscular junctions can modulate mitochondrial respiration and biogenesis, synaptic stability, and muscle strength as well as control the muscle response to exercise and activity. The overarching hypothesis of this K01 proposal is that sympathetic neurons are required for the functional and metabolic stability of the neuromuscular unit in normal and pathological conditions. We will first test the necessity and sufficiency of sympathetic nerve activity on metabolic and motor control using a novel technology, BioLuminescent OptoGenetics (BL-OG) in normal, uninjured animals. My research has shown that exercise and neuronal activity strikingly enhance peripheral axon regeneration and significantly improves functional recovery following complete nerve and spinal cord injuries in preclinical models. However, while clinician scientists recognize the importance of exercise to promote axon regeneration and metabolic health, the translational potential of exercise has many limitations. Many patients are not candidates for exercise due to co-morbidities that preclude rehabilitation, necessary immobilization of a limb following surgical nerve repair, unknown dose requirement of exercise, and low patient compliance. Further limitations are that nearly 70% of the skeletal muscle of people with a spinal cord injury is paralyzed, and there are no guidelines for electrically induced exercise of paralyzed muscle. Experimental evidence also shows that sympathetic axon regrowth may even be inhibited by certain types of treatments, such as electrical stimulation. Thus, other goals of this work are to investigate whether increasing sympathetic activity 1) promotes or inhibits sympathetic axon regeneration after peripheral nerve injury, and 2) can rescue the muscle bioenergetic and motor control deficits after spinal cord injury.