Peripheral Blood Exosome Lipids as Biomarkers of Disease Activity in Crohn’s Disease

摘要 炎症性肠病(IBD)患者的管理需要疾病状态的知识来告知 治疗决定。临床疾病活动指数、C反应蛋白等常用生物标志物 C反应蛋白和粪便钙保护素对肠炎的敏感度和特异度低于最佳1。数据 提示外周血外周血外周体(PBE)脂组成可区分活动期IBD和IBD 正常患者(图1)。我们认为PBE脂质成分将为临床医生提供高度敏感的 和特定的生物标志物，在不进行侵入性检测的情况下评估疾病的活动性。识别细微疾病的必要性 源于“深度缓解”应该是治疗的终点这一共识结论。因此， 监测意在抑制亚临床炎症的患者已成为一种治疗方法 进球3.Exosome是一种脂质包裹的亚细胞(60-80 nm)结构，在 来自肠上皮细胞(IEC)、激活的白细胞(如中性粒细胞、巨噬细胞、树突状细胞等)。 炎症时的间质细胞。我们使用超高分辨率Orbitrap质谱仪 分析患者PBE的脂质成分(&gt；25/组)。PBE脂类的主成分分析(PCA) 强度显示了活动期IBD和正常对照组之间数据点的广泛分离以及热图 差异丰度分析显示组内相关性高，组间相关性低 这表明，与疾病活动性相关的不同脂类可以被分解。在这个为期两年的项目中，我们 建议收集1)中重度、2)轻度活动期和3)静止期克罗恩病(CD)患者的血浆 患者以及炎症性疾病(艰难梭菌感染)和4)正常对照。使用CD可以让我们测试 PBE成分是否检测到轻微(在许多情况下，亚临床)疾病活动的水平 患者未处于深度缓解状态，这是医学治疗的目标。在目标1中，PBE基于脂质的分类器将是 开发用于区分轻度活跃的CD和严重活跃的CD和对照。在目标2中，PBE类脂将是 在治疗前后对个别患者进行纵向检查，以确定与临床相关的血脂 回应。这些信息还将传递给目标1，以开发更强大的分类器。测试模式 有反应和难治患者的PBE脂类旨在提高分类器的稳健性。 目标1和目标2的研究因纳入第二个临床地点(贝勒大学)而大大加强 提供样本以验证(或不验证)肯塔基大学的数据。长期目标将是证明 为鉴别提供一组新的生物标记物的“外体脂肪信号”小组的研究 CD疾病活动性的水平和告知治疗决定。我们发布了CD exosome的创建 在大多数患者中，脂质生物标记物检测将不再需要后续的内窥镜检查。

Abstract Management of inflammatory bowel disease (IBD) patients requires knowledge of disease status to inform treatment decisions. Commonly used biomarkers such as clinical disease activity indices, C reactive protein (CRP) and fecal calprotectin achieve suboptimal sensitivity and specificity for intestinal inflammation1. Data provided indicate that peripheral blood exosome (PBE) lipid composition distinguishes active IBD from normal patients (Fig. 1). We contend that PBE lipid compositions will provide clinicians with a highly sensitive and specific biomarker to assess disease activity without invasive testing. The need to identify subtle disease derives from the consensus conclusion that “deep remission” should be the endpoint of therapy. Thus, monitoring of patients with intent to suppress subclinical inflammation has emerged as a treatment goal3. Exosomes are lipid-encased, subcellular (60-80 nm) structures released into the peripheral blood at from intestinal epithelial cells (IEC), activated leukocytes (e.g. neutrophils, macrophages, dendritic cells, etc.) and mesenchymal cells during inflammation3. We used an ultrahigh resolution Orbitrap mass spectrometer to analyze lipid compositions of PBEs from patients (>25/group). Principal component analysis (PCA) of PBE lipid intensities showed a wide separation of datapoints between active IBD and normal controls and a heatmap analysis of differential abundance revealed high within-group correlations and low between-group correlations suggesting that distinct lipids can be resolved that correlate with disease activity. In this two year project, we propose to collect plasma from 1) moderate-severe, 2) mildly-active and 3) quiescent Crohn’s disease (CD) patients as well as inflammatory (C. difficile-infected) and 4) normal controls. Using CD allows us to test whether PBE composition detects levels of mild (in many cases, subclinical) disease activity as this identifies patients not in deep remission, a goal of medical therapy. In Aim 1, PBE lipid-based classifiers will be developed to discriminate mildly-active from severely-active CD and controls. In Aim 2, PBE lipids will be examined longitudinally within individual patients before and after therapy to identify lipids correlate with clinical response. Such information will also be passed to Aim 1 to develop more robust classifiers. Testing patterns of PBE lipids in responsive and refractory patients is intended to improve the robustness of the classifiers. Studies in Aim 1 and 2 are greatly enhanced by the inclusion of a second clinical site (Baylor University) to provide samples to validate (or not) data from University of Kentucky. The long-term goal will be to justify studies to identify a “exosomal lipid signature” panel that provide a novel set of biomarkers for discriminating levels of CD disease activity and informing treatment decisions. We post that the creation of a CD exosome lipid biomarker test will obviate the need for follow-up endoscopy in the majority of patients.