OTOENDOSCOPE PAIRED AGENT IMAGING OF OPIOID RECEPTOR KINETICS DURING DEPENDENCY AND WITHDRAWAL

总结/摘要 阿片类药物滥用现在在美国是一种全面的流行病。疾控中心估计有超过16万5千人 自1999年以来，已有3,900人死于处方阿片类药物过量， 处方阿片类药物因此，阿片类药物使用障碍（OUD）估计每年给社会造成550亿美元的损失。 是整个NIH年度预算的两倍。大多数OUD患者开始服用阿片类药物 他们的医生管理疼痛的工伤或受伤期间持续的军事服务，往往没有任何 了解依赖的风险。越来越清楚的是，依赖和成瘾的风险是 科学界也大大低估了，最常用的阿片类药物 在任何滥用的药物类别中，身体和生理依赖性最高。然而，在这方面， 天真人群中的遗传差异使某些个体一旦暴露于 阿片类药物在临床上或其他方面。这些遗传差异导致μ阿片受体（莫尔） 表型在结合、脱敏和内化行为上不同， 成瘾的风险更高，戒断症状的严重程度更高（复发的最大预测因素）。配对 试剂成像（派）是一种可以在体内定量受体-配体结合潜力（BP）的已建立的方法， 并且如果荧光激动剂和拮抗剂对被抑制， 而不是非靶向/靶向药物对。这两个参数-内化率和结合 潜在的-被假设为预测OUD在初治使用者中的风险和在恢复个体中复发的风险 从OUD。我们假设阿片受体表达和行为的这些临床上重要的差异 可以通过内耳的耳内窥镜配对试剂成像（OPAI）来测量。因此，我们寻求R21 在NIBIB“开拓者”的机会下获得资金：（1）设计和组装刚性耳内窥镜， 派的阿片类药物结合动力学在内耳，和（2）使用耳内窥镜配对代理成像（OPAI）定量 慢性阿片类药物暴露期间和纳洛酮诱导戒断后的受体行为 荧光标记的阿片肽激动剂/拮抗剂对。耳内窥镜将包括商业 可用Storz内窥镜（直径<2.5 mm）连接到一个小模块，将图像分为三个波段 (RGB、700-和800-荧光），然后传输到单个sCMOS相机。一种多LED光源， 特定的照明和激发带通过Storz光导耦合器向下传输到内窥镜。 在本研究的最后，我们将提出三个假设：（1）内耳螺旋神经节细胞可以被成像 使用耳内窥镜以定量结合潜力和内化，（2）结合和内化 率预测慢性阿片类药物暴露和纳洛酮诱导的戒断在毛丝鼠模型的OUD。的 这项研究的潜在影响是巨大的：能够量化阿片受体的个体差异， 非侵入性行为可以改善OUD风险个体远离阿片类药物的转移， 预防使用阿片类药物治疗慢性疼痛的患者滥用阿片类药物，并有助于 OUD通过对戒断严重程度和复发风险进行分层，以提供个体化、适当的 支持.

Summary / Abstract Opioid abuse is now a full-fledged epidemic in the United States. The CDC estimates that over 165,000 people have died from prescription opioid overdoses since 1999, and that 3,900 people start nonmedical use of prescription opioids each day. As a result, opioid use disorder (OUD) costs society an estimated $55 billion per year—twice the annual budget of the entire NIH. Most individuals with OUD began taking opioids on the advice of their physician to manage pain from work injury or injury sustained during military service, often without any knowledge of the risks of dependency. It is increasingly clear that the risks of dependency and addiction were greatly underestimated by the scientific community as well, that the most commonly administered opioids have among the highest physical and physiological dependence potentials of any abused class of drugs. However, genetic differences within the naïve population predispose certain individuals to OUD once they are exposed to opioids in a clinical setting or otherwise. These genetic differences result in mu-opioid receptor (MOR) phenotypes that differ in binding, desensitization and internalization behavior—differences which are associated with higher risk of addiction and higher severity in withdrawal symptoms (the biggest predictor of relapse). Paired agent imaging (PAI) is an established method that can quantify receptor-ligand binding potential (BP) in vivo, and could the ability to measure rate of receptor internalization if fluorescent agonist and antagonist pairs are used instead of untargeted/targeted agent pairs. These two parameters—internalization rate and binding potential—are hypothesized to predict risk of OUD in naïve users and risk of relapse in individuals recovering from OUD. We hypothesize that these clinically important differences in opioid receptor expression and behavior can be measured by otoendoscopic paired agent imaging (OPAI) of the inner ear. Therefore, we seek R21 funding under the NIBIB “trailblazer” opportunity to: (1) design and assemble a rigid otoendoscope to perform PAI of opioid binding kinetics in the inner ear, and (2) use otoendoscopic paired agent imaging (OPAI) to quantify receptor behavior during chronic opioid exposure and following naloxone-induced withdrawal using fluorescently-labeled opioid peptide agonist/antagonist pairs. The otoendoscope will consist of commercially available Storz endoscope (<2.5 mm diameter) coupled to a small module that splits the image into three bands (RGB, 700- and 800- fluorescence) and then transmits to a single sCMOS camera. A multi-LED light source of specific illumination and excitation bands is transmitted down the endoscope via the Storz light guide coupler. By the end of the project, we will address three hypotheses: (1) spiral ganglia cells of the inner ear can be imaged using an otoendoscope in order to quantify binding potential and internalization, (2) binding and internalization rate predict chronic opioid exposure and naloxone-induced withdrawal in a chinchilla model of OUD. The potential impact of this research is substantial: the ability to quantify the individual variations in opioid receptor behavior non-invasively could improve the diversion of individuals at-risk for OUD away from opioids, could prevent opioid abuse in patients using opioids for chronic pain management, and could aid in the recovery of OUD by stratifying severity of withdrawal and, by extension, relapse risk to provide individualized, appropriate support.