Identifying Genetic Variants Associated with Opioid Overdose Mortality

美国疾病控制与预防中心记录了美国阿片类药物过量流行的恶化情况。 男性和女性、非西班牙裔白人和黑人以及所有年龄段的死亡人数都有所增加 25.24岁以上人群导致疫情的相互关联的趋势包括 超过15年的处方阿片类药物过量死亡和最近的激增 非法阿片类药物(即海洛因和芬太尼相关药物)造成的过量死亡。服药过量死亡 从2010年到2016年，美国涉及海洛因的案件增加了近五倍，而涉及毒品的案件 芬太尼及其类似物从2015年到2016年翻了一番以上。24，26改进研究 因此，理解阿片类药物引起的呼吸抑制的病理生理学是一种公共健康 势在必行。以前在这一领域的遗传学研究仅限于对a基因进行分型的候选基因研究。 少数样本中的SNP大小非常适中，主要由欧洲血统(EA)个人组成。 我们建议进行第一次因阿片类药物引起的呼吸抑制而导致的死亡。我们的大型 EA和非裔美国人(AA)的子样本将分别超过最大的先前研究的样本 数量级。我们将使用两个不同的对照组，大型先前基因分型的EA和AA 阿片依赖个人和一般人群成员的样本分别非常适合于 确定反复使用的影响和阿片类药物使用障碍的共同影响。我们的研究 设计的重点是一个明确的结果衡量标准，即阿片类药物引起的呼吸抑制所致的死亡，这 预计将为我们的调查提供额外的动力。以前的许多研究都不太清楚地检查了 方便样本(例如，儿科)的标定结果(临床观察到的呼吸抑制) 外科病人)。这项修订后的提案非常有能力识别EAs和EAs中的常见遗传变异 AAS与阿片类药物引起的呼吸抑制的易感性有关。我们还建议进行 首次检测阿片类药物过量患者脑内基因表达的变化 参与阿片类药物引起的呼吸抑制的区域包括Prebötzinger复合体， 臂旁核/Kölliker-Fuse核(PB/KF)和中缝核。这项补充调查将提供 对这一过程背后的病理生理学有更深入的了解，并能够检查 与GWAS相关的常见变异相关的基因表达。具体目标是：1) 从15,000名意外阿片类药物过量死者(N‘s EA~10,000；AA~5000)中提取DNA。2)进行 阿片类药物引起的呼吸抑制，包括阿片类药物之间的风险分担，以及药物特有的影响， 将这些个体与两大先前GWAS基因分型的AA和EA个体组进行比较：1) 那些有阿片类药物使用障碍的人；以及2)在普通人群样本中确定的人。3)审查 延髓Prebötzinger复合体、中缝核和桥脑PB/KF的差异基因表达 意外阿片类药物过量死亡者(N=50)与单独匹配组的核比较 死于其他原因：一)有记录的阿片类药物使用者(N=50)；和二)阴性的死者 毒理学筛选(N=50)，并将这些区域的差异表达与目标2的GWAS数据相关联， 为GWAs的新发现提供生物学基础。

The CDC has documented the worsening “opioid overdose epidemic” in the U.S. Opioid overdose deaths have increased among males and females, non-Hispanic whites and blacks, and all age groups over age 25.24 Interrelated trends contributing to the epidemic include an increase in prescription opioid overdose deaths spanning more than 15 years and more recent surges in overdose deaths due to illicit opioids (i.e., heroin and fentanyl-related drugs). Overdose deaths involving heroin rose nearly five-fold in the U.S. from 2010 to 2016 while those involving fentanyl and its analogues more than doubled from 2015 to 2016.24,26 Research to improve understanding of the pathophysiology of opioid-induced respiratory depression is thus a public health imperative. Prior genetic research in this area has been limited to candidate gene studies that genotyped a handful of SNPs in samples of very modest size that consisted primarily of European ancestry (EA) individuals. We are proposing to conduct the first GWAS of death due to opioid-induced respiratory depression. Our large EA and African American (AA) sub-samples will each exceed that of the largest prior study by well over an order of magnitude. We will utilize two distinct comparison groups, large previously-genotyped EA and AA samples of opioid dependent individuals and general population members that are well-suited, respectively, to identify effects contingent upon repeated use and those shared with liability of opioid use disorder. Our study design focuses on a definitive outcome measure, death due to opioid-induced respiratory depression, which is expected to provide additional power for our investigation. Many prior studies have examined less clearly demarcated outcomes (clinically observed respiratory depression) in convenience samples (e.g. pediatric surgical patients). This revised proposal is very well-powered to identify common genetic variants in EAs and AAs associated with liability for opioid-induced respiratory depression. We are also proposing to conduct the first examination performed in human opioid overdose decedents of gene expression changes in brain regions involved in opioid-induced respiratory depression including the preBötzinger complex, parabrachial/Kölliker-Fuse nuclei (PB/KF), and raphe nucleus. This complementary investigation will provide additional insight into the pathophysiology underlying this process and enable examination of alterations in gene expression associated with common variants implicated in the GWAS. The specific aims are: 1) To obtain DNA from 15,000 accidental opioid overdose decedents (N's EA ~10,000; AA ~5000). 2) To conduct a GWAS of opioid-induced respiratory depression including risk shared across opioids, and drug-specific effects, comparing these individuals to two large previously GWAS-genotyped groups of AA and EA individuals: 1) those with opioid use disorder; and 2) those ascertained in general population samples. 3) To examine differential gene expression in the medullary preBötzinger complex and raphe nucleus, and pontine PB/KF nuclei in those who died from accidental opioid overdose (N=50) compared with separate matched groups who died from other causes: i) those with documented opioid use (N=50); and ii) decedents who had negative toxicology screens (N=50) and to relate differential expression in these regions to GWAS data for Aim 2, providing a biological foundation for novel GWAS discoveries.