In-vivo Assessment of Neuroinflammation in Painful Trigeminal Neuropathy

痛性三叉神经病是指面部疼痛在一个或多个部位的分布(S) 三叉神经的分支，与创伤、病毒感染或其他原因引起的神经损伤有关 原因。PTN对内科和外科治疗非常不敏感。显然，更深入地了解 PTN的分子发病机制亟待改进对其的治疗。 在过去的六年里，我们的团队已经证明了18 kDa水平的增加 转位蛋白(TSPO，使用正电子发射断层扫描)和/或肌醇(Mins，使用 磁共振波谱)，在各种慢性疼痛的患者的大脑中。因为两家TSPO 而MIN被胶质细胞过度表达，我们的结果表明神经炎症可能是一种普遍存在的 这种现象可以在多种病因不同的人类疼痛障碍中观察到，但在 中枢神经系统内特定紊乱的空间分布。尽管取得了这些进展，但临床 这些脑部炎症信号的意义(例如，神经炎症成像是否可以用于 确定更有可能对抗炎治疗有反应的患者)仍有待评估。 在这个探索性项目中，我们将招募计划接受口服类固醇治疗的PTN患者。全 参与者将由经验丰富的神经科医生进行临床评估，并在开始治疗之前， 通过集成(即同时)正电子发射断层扫描/磁共振接收脑成像 成像(PET/MRI)和用于TSPO的第二代放射性配体[11C]PBR28，我们已经使用它来 显示疼痛或神经退行性疾病患者的神经胶质激活。扫描结束后，参与者 将接受为期3周的类固醇强的松治疗，然后再进行一次临床/行为检查。 临床特征将包括定量感觉测试和问卷调查。患者的影像数据将 与现有的健康对照和不同病因的慢性疼痛患者的数据集进行比较 (慢性下腰痛)，以评估我们的发现对PTN的特异性。 对于目标1，我们将使用多模式评估疼痛三叉神经病的体内神经炎症。 脑部成像。对于目标2，我们将测试大脑神经炎症信号预测类固醇反应的能力。 治疗。这项工作将促进我们对慢性神经炎临床意义的理解。 疼痛状况。 虽然这个项目的重点是神经病理性疼痛，但确定胶质细胞在发育和 人类持续性神经病理性疼痛和疼痛相关残疾的维持将具有重要的实际意义 对广泛的疼痛障碍的管理的影响。例如，它将为关键的人类提供 有证据表明，制定专门针对神经胶质调节的干预措施是合理的。

Painful trigeminal neuropathy (PTN) is defined as facial pain in the distribution(s) of one or more branches of the trigeminal nerve, associated with neural damage induced by trauma, viral infection, or other causes. PTN is very unresponsive to medical and surgical treatments. Clearly, a more in-depth knowledge of the molecular pathomechanisms of PTN are in urgent need to improve the management of this disorder. In the last six years our group has demonstrated the presence of increased levels of the 18kDa translocator protein (TSPO, using positron emission tomography) and/or myo-inositol (mIns, using magnetic resonance spectroscopy), in the brains of patients with various chronic pain conditions. Because both TSPO and mIns are overexpressed by glial cells, our results suggest that neuroinflammation might be a pervasive phenomenon that can be observed across multiple, etiologically heterogeneous human pain disorders, but in a disorder-specific spatial distribution within the central nervous system. Despite these advances, the clinical significance of these brain inflammatory signals (e.g., whether neuroinflammation imaging could be used to identify patients more likely to respond to anti-inflammatory therapies) remains to be evaluated. In this exploratory project, we will recruit PTN patients scheduled to receive oral steroid therapy. All participants will be evaluated clinically by an experienced neurologist and, prior to commencing their treatment, receive brain imaging with integrated (i.e., simultaneous) positron emission tomography / magnetic resonance imaging (PET/MRI) and [11C]PBR28, a second-generation radioligand for TSPO, which we have used to demonstrate glial activation in patients with pain or neurodegenerative disorders. After the scan, participants will undergo a 3-week treatment with the steroid prednisone, followed by another clinical/behavioral visit. Clinical characterization will include quantitative sensory testing and questionnaires. Patients’ imaging data will be compared to an existing dataset of healthy controls and chronic pain patients with a different etiology (chronic low back pain) to assess the specificity of our findings to PTN. For Aim 1, we will assess in-vivo neuroinflammation in painful trigeminal neuropathy, using multimodal brain imaging. For Aim 2 we will test the brain neuroinflammatory signals’ ability to predict response to steroid treatment. This work will advance our understanding of the clinical significance of neuroinflammation in chronic pain conditions. While this project is focused on neuropathic pain, identifying the role of glia in the development and maintenance of persistent neuropathic pain and pain-related disability in humans will have important practical implications for the management of a wide range of pain disorders. For instance, it will provide crucial human evidence contributing to rationale for the development of tailored interventions focused on glial modulation.