Epigenetic Determinants Influencing Development and Evolution of Chronic Post-surgical Pain in Children Undergoing Musculoskeletal Surgery.

项目总结 脊柱融合和胸部修复是青少年接受的最痛苦的肌肉骨骼手术之一， 慢性术后疼痛(CPSP)发生率高。CPSP不利于恢复，并增加了 残疾以及处方阿片类药物滥用。了解CPSP风险对于开发有效的CPSP非常重要 预防和治疗策略。尽管遗传、心理社会和环境因素解释了一些 在CPSP风险的方差中，在CPSP风险预测和对纵向风险的理解方面仍然存在重大差距 基因环境对手术后长期疼痛反应的影响。这将我们引向我们的全球 表观遗传过程将影响CPSP的发展和进化的假说。DNA甲基化 (DNaM)是一种关键的表观遗传学机制，可影响急性疼痛到慢性疼痛的转录和转换。 初步数据：我们在脊柱外科受试者中进行的先导性表观基因组关联研究(Ewas)显示 CPSP与差异dNaM相关的39个基因丰富了GABA，多巴胺-DARPP32反馈 CAMP和免疫信号通路。我们先前的研究发现，Mu阿片受体基因启动子的dNaM， 围手术期疼痛和阿片类药物暴露可预测CPSP，使我们相信dNaM介导了这种联系 具有长期疼痛表型的围手术期应激源。细胞因子水平和dNaM-表达增加 CPSP(试点数据)中的相关性表明不同的表观遗传调控影响免疫细胞特异性基因 在CPSP中的表达。科学目标是确定CPSP的血液dNaM生物标志物并评估 CPSP相关表观遗传变异与疼痛-阿片类药物暴露和炎症相关的时间起源 回应。以血液为基础的dNaM作为CPSP生物标志物的潜在用途的前提是 报告的脑-血dNaM相关性和血dNaM特征的跨组织比较研究 几种神经表型。目的1：确定和验证预测CPSP的差异甲基化区域。 工作假说是CPSP与术前血液中的dNaM标志物显著相关。 调整人口学、心理社会和围手术期因素后的样本。我们将进行一次前瞻性的， 用于发现-验证(N=1165名接受脊柱融合术的阿片类药物天真儿童)和复制的多点EWAS 候选标记物(N=300名接受胸腔修补术的儿童)。由于横断式表观遗传学研究 受反向因果偏差和遗传变异混杂因素的潜在影响，我们提出了新的纵向 评估围手术期应激相关dNaM变化的研究。目标2：确定以下方面的纵向变化 与疼痛和阿片类药物暴露相关的dNaM特征，并探讨它们在调节与 CPSP。目的3：研究细胞因子谱、免疫细胞亚群和免疫细胞的表观遗传调控 CPSP中特异基因的表达。预计这项研究将确定新的表观遗传生物标记物 CPSP，为CPSP进化中的纵向表观遗传机制提供了新的见解，并揭示了 CPSP有希望的治疗靶点，对其他慢性疼痛疾病具有广泛的影响。

PROJECT SUMMARY Spine fusion and pectus repair are among the most painful musculoskeletal surgeries adolescents undergo, with a high incidence of chronic postsurgical pain (CPSP). CPSP is detrimental to recovery and increases the risk for disability as well as prescription opioid abuse. Understanding CPSP risk is important for development of effective preventive and therapeutic strategies. Although genetic, psychosocial and environmental factors explain some of the variance in CPSP risk, there remain critical gaps in CPSP risk prediction and understanding of longitudinal gene-environmental influences on long-term pain responses after surgery. This leads us to our global hypothesis that epigenetic processes will influence the development and evolution of CPSP. DNA methylation (DNAm) is a key epigenetic mechanism known to influence transcription and transition of acute to chronic pain. Preliminary data: Our pilot epigenome-wide association study (EWAS) in spine surgical subjects showed that CPSP is associated with differential DNAm in 39 genes which enrich GABA, Dopamine-DARPP32 Feedback in cAMP and immune signaling pathways. Our previous findings that DNAm of Mu opioid receptor gene promoter, perioperative pain and opioid exposures predict CPSP, lead us to believe that DNAm mediates the association of perioperative stressors with long-term pain phenotypes. Increased cytokine levels and DNAm-expression correlations in CPSP (pilot data) suggest differential epigenetic regulation influencing immune cell-specific gene expression in CPSP. Scientific objectives are to determine blood DNAm biomarkers for CPSP and evaluate temporal origins of CPSP-associated epigenetic variation in relation to pain-opioid exposures and inflammatory responses. The premise for the potential utility of blood based DNAm as CPSP biomarkers is supported by cross tissue comparison studies of brain-blood DNAm correlations and blood DNAm signatures reported for several neural phenotypes. Aim 1: Determine and validate differentially methylated regions predictive of CPSP. The working hypothesis is that CPSP will be significantly associated with DNAm markers in preoperative blood samples after adjusting for demographic, psychosocial and perioperative factors. We will conduct a prospective, multisite EWAS for discovery-validation (N=1165 opioid-naïve children undergoing spine fusion) and replication of candidate markers (N=300 children undergoing pectus repair). Since cross-sectional epigenetic studies are potentially affected by reverse causation bias and genetic variation confounders, we propose novel longitudinal studies to evaluate perioperative stress related DNAm changes. Aim 2: Determine longitudinal changes in DNAm profiles associated with pain and opioid exposures and explore their role in mediating associations with CPSP. Aim 3: Characterize cytokine profiles, immune cell subsets and epigenetic regulation of immune cell specific gene expression in CPSP. It is anticipated that this study will identify novel epigenetic biomarkers for CPSP, provide novel insights into longitudinal epigenetic mechanisms in the evolution of CPSP, and uncover promising therapeutic targets for CPSP, with extended implications for other chronic pain conditions.