Stimulation of Cervical Excitatory Interneurons to Restore Breathing After Chronic Cervical Spinal Cord Injury

刺激颈部兴奋性中间神经元以恢复慢性颈髓损伤后的呼吸

• 批准号: 10360818
• 负责人: Shekar N. Kurpad
• 金额: --
• 依托单位: CLEMENT J. ZABLOCKI VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10360818
• 关键词: Aging; Anatomy; Area; Biological; Brain Stem; Breathing; Cell Nucleus; Cervical; Cervical spinal cord injury; Cervical spinal cord structure; Cholera Toxin Protomer B; Chronic; Chronic Phase; Clinical; Communication; Communities; Data; Dependence; Development; Devices; Electromyography; Elements; Ensure; Face; Goals; Health; Impairment; Incidence; Individual; Injury; Interneurons; Knowledge; Life; Maintenance; Maps; Mechanical ventilation; Military Personnel; Modernization; Modification; Morbidity - disease rate; Motor Neurons; Motor output; Mus; Muscle; Neuronal Plasticity; Neurons; Neurosciences; Operative Surgical Procedures; Outcome; Output; Patients; Pharmacogenetics; Phase; Play; Population; Publishing; Quality of life; Recovery; Recovery of Function; Respiration Disorders; Respiratory Center; Respiratory Diaphragm; Respiratory Insufficiency; Respiratory physiology; Role; Shapes; Spinal; Spinal Cord; Spinal cord injury; Spinal cord injury patients; Stress; Survivors; Synapses; Techniques; Technology; Therapeutic; Time; Tracer; Transgenic Mice; Trauma; United States; United States Department of Veterans Affairs; Ventilator; Vertebral column; Veterans; Viral; Vision; Weaning; Whole Body Plethysmography; Work; base; designer receptors exclusively activated by designer drugs; disability; experimental study; health care delivery; high risk; improved; innovation; insight; military veteran; mortality; neural network; novel; novel strategies; novel therapeutic intervention; prevent; relating to nervous system; respiratory; sex; therapeutic target; therapy development; treatment strategy; ventilation

Dysfunctional breathing is a significant cause of morbidity and mortality after cervical SCI (cSCI). The ability to restore breathing in the chronic phase after cervical SCI (cSCI) is an overwhelming yet important goal. The diaphragm, the major inspiratory muscle, is innervated by phrenic motoneurons (PMNs) located in the cervical spinal cord (C3-C5). Cervical interneurons synapse onto PMNs and discharge in synchrony with phrenic inspir- atory output and modulate breathing. Premotor neurons within the rostral ventral respiratory group of neurons (rVRG) in the brainstem provide the main inspiratory drive to the spinal respiratory circuitry. Cervical spinal cord injury (SCI) disrupts the communication between rVRG and the spinal respiratory circuitry resulting in significant respiratory compromise. We recently demonstrated that pharmacogenetic stimulation of cervical excitatory in- terneurons (eINs) immediately after cSCI rescues breathing in mice; however, it is not known if this strategy will be effective in improving breathing in the chronic phase of cSCI. At the chronic stage, the respiratory network is known to undergo significant modifications. Moreover, our previous work in non-traumatic compressive injury to the cervical spinal cord demonstrated that cervical eINs play an integral role in promoting plasticity and main- taining ventilation despite a significant loss of PMNs. Given that cervical eINs integrate into the respiratory net- work, and they are necessary for the spontaneous respiratory recovery, they emerge as critical therapeutic tar- gets for respiratory recovery in the chronic phase after traumatic cSCI. We hypothesize that providing selec- tive excitatory input to surviving PMNs at the late stage of cSCI will enhance PMNs output and respiratory recovery. The first objective of this proposal aims to gain more significant insights into the status of the respira- tory neural network after chronic cSCI. The second objective of this proposal will examine a novel treatment strategy involving selective stimulation of cervical eINs to promote respiratory recovery in the chronic phase after cSCI. In aim 1, we will assess the survival of PMNs following C2 hemisection injury (C2Hx) using the monosynaptic retrograde tracer Cholera Toxin Subunit B to specifically track the PMNs. In the second part of Aim 1, we will simultaneously map the input-output connectivity of the cervical respiratory elements, the PMNs and the prephrenic cervical eINs, in the naïve-uninjured state and after cSCI. In Aim 2, we will selectively stimulate the cervical eINs in the region of the phrenic nuclei after chronic cSCI using the DREADD technology. This technique has innovative applications due to its ability to activate or silence neuronal populations non-invasively. The effect of stimulating cervical eINs on promoting respiratory recovery after chronic cSCI will be assessed using electro- myography and whole-body plethysmography. The expected outcomes of the proposed experiments are inno- vative as it will increase our knowledge of the spinal respiratory network after chronic cSCI and facilitate the development of a novel strategy to restore breathing in the chronic phase of cSCI. These results will have a meaningful positive impact on the health and survival of veterans with SCI, and the strategy examined here has the potential to be implemented for weaning patients off mechanical ventilation in the chronic phase after cSCI when promoting recovery has remained a daunting task. Additionally, SCI represents a significant focus area of the veterans, about 7% of those living with SCI in the United States have sustained their SCI while actively serving. Injuries are often due to penetrating injuries such as from gunshots or high-powered explosive devices. As such, military personnel with SCI face even more long-term disabilities than those endured by civilians with SCI, and the issues more pronounced in veterans with cSCI and respiratory dysfunctions.

呼吸功能障碍是颈椎 SCI (cSCI) 后发病和死亡的一个重要原因。 恢复颈椎 SCI (cSCI) 后慢性期的呼吸是一个压倒性但重要的目标。 膈肌是主要的吸气肌，由位于颈椎的膈运动神经元 (PMN) 支配 脊髓（C3-C5）的颈间神经元与 PMN 突触并与膈吸气同步放电。 口腹侧呼吸神经元组内的前运动神经元。 脑干中的 (rVRG) 为脊髓呼吸回路提供主要的吸气驱动。 损伤（SCI）破坏了 rVRG 和脊髓呼吸回路之间的通讯，导致显着的 我们最近证明了宫颈兴奋性的药物遗传学刺激。 cSCI 挽救小鼠呼吸后立即释放三元神经元 (eIN)；然而，尚不清楚这种策略是否有效。 有效改善 cSCI 慢性期的呼吸 在慢性期，呼吸网络处于瘫痪状态。 此外，我们之前在非创伤性压缩损伤方面的工作也发生了重大变化。 颈脊髓的研究表明，颈椎 eIN 在促进可塑性和维持功能方面发挥着不可或缺的作用。 尽管 PMN 大量减少，但仍保持通气，因为颈部 eIN 已整合到呼吸系统中。 工作，并且它们对于自主呼吸恢复是必需的，因此它们成为关键的治疗目标 创伤性 cSCI 后慢性期的呼吸恢复，我们勇敢地提供了选择。 在 cSCI 后期对幸存的 PMN 进行积极的兴奋性输入将增强 PMN 的输出和呼吸 该提案的第一个目标是更深入地了解呼吸系统的状况。 该提案的第二个目标是研究一种新的治疗方法。 选择性刺激颈部 eIN 的策略，以促进术后慢性期的呼吸恢复 cSCI。 在目标 1 中，我们将使用单突触评估 C2 半切损伤 (C2Hx) 后 PMN 的存活率 逆行示踪剂霍乱毒素亚基 B​​ 专门追踪 PMN 在目标 1 的第二部分中，我们将。 同时绘制颈部呼吸元件、PMN 和呼吸系统的输入输出连接 在目标 2 中，在未受伤状态下和 cSCI 后，我们将选择性地刺激膈前颈椎 eIN。 使用 DREADD 技术对慢性 cSCI 后膈核区域的颈部 eIN 进行观察。 由于其能够非侵入性地激活或沉默神经群体，因此具有创新的应用效果。 颈椎刺激 eIN 对促进慢性 cSCI 后呼吸恢复的作用将使用电进行评估 所提出的实验的预期结果是创新的。 因为它将增加我们对慢性 cSCI 后脊髓呼吸网络的了解，并促进 开发一种新的策略来恢复 cSCI 慢性期的呼吸这些结果将产生一定的影响。 对患有 SCI 的退伍军人的健康和生存产生了有意义的积极影响，这里研究的策略 cSCI 后慢性期患者撤机机械通气的可能性 此外，SCI 代表了一个重要的重点领域。 对于退伍军人来说，在美国，大约 7% 的 SCI 患者在积极治疗的同时维持了 SCI 服役时受伤通常是由于枪伤或高能爆炸装置造成的穿透伤。 因此，患有 SCI 的军事人员比患有 SCI 的平民面临更长期的残疾。 脊髓损伤，并且这些问题在患有脊髓损伤和呼吸功能障碍的退伍军人中更为明显。