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

项目摘要 脊柱融合和胸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）的发生率很高。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风险对于制定有效的 预防和治疗策略。尽管遗传、社会心理和环境因素解释了一些 在CPSP风险的变化中，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。 基因环境对术后长期疼痛反应的影响这将我们带到我们的全球 假设表观遗传过程将影响CPSP的发展和进化。DNA甲基化 DNA m是已知影响转录和从急性疼痛向慢性疼痛转变的关键表观遗传机制。 初步数据：我们在脊柱外科受试者中进行的初步表观基因组关联研究（EWAS）显示， CPSP与39个基因中的差异DNAm相关，这些基因富集GABA，多巴胺-DARPP 32反馈， cAMP和免疫信号通路。我们以前的研究发现，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预测CPSP，使我们相信DNAm介导了这种关联 围手术期应激源与长期疼痛表型。细胞因子水平和DNAm表达增加 CPSP（试点数据）的相关性表明，差异表观遗传调节影响免疫细胞特异性基因 在CPSP中表达。科学目的是确定CPSP的血液DNAm生物标志物， 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 应答基于血液的DNAm作为CPSP生物标志物的潜在效用的前提得到以下支持： 脑-血DNAm相关性和血液DNAm特征的跨组织比较研究， 几种神经表型目的1：确定和验证差异甲基化区域预测CPSP。 工作假设是CPSP与术前血液中的DNAm标记物显著相关 调整人口统计学、社会心理学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例接受脊柱融合术的阿片类药物初治儿童）和复制的多中心EWAS 候选标记物（N=300例接受胸部修复术的儿童）。由于横截面表观遗传学研究是 潜在的影响反向因果偏差和遗传变异混杂因素，我们提出了新的纵向 研究评估围手术期应激相关的DNAm变化。目标2：确定 与疼痛和阿片类药物暴露相关的DNAm谱，并探讨其在介导 CPSP。目的3：研究细胞因子谱、免疫细胞亚群及免疫细胞表观遗传调控 CPSP中特异性基因表达。预计这项研究将确定新的表观遗传生物标志物， CPSP，提供了新的见解纵向表观遗传机制的进化CPSP，并揭示 CPSP的有前途的治疗靶点，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.