Novel Biomarkers in Aortic Aneurysms and Acute Aortic Dissection

描述（由申请人提供）：本申请涉及广泛的挑战领域（06）“使能技术”和具体的变更主题，06- HL-101“开发用于评估容易破裂或剥离的主动脉瘤的技术”。主动脉夹层是指人体主要血管（主动脉）的壁上出现撕裂。潜在的病理是多种多样的，易感因素包括主动脉瘤和结缔组织疾病。这是一个危及生命的事件，特别是如果夹层位于胸主动脉的上升部分，因为它可能通过损害主动脉瓣和冠状动脉的血液流动而导致全身心肌缺血。主动脉破裂更为罕见，但几乎总是与100%的死亡率相关。在当前的提案中，我们解决了临床相关和迫切需要阐明的机制：(1)将使我们能够识别已知主动脉瘤患者中有夹层风险的患者；(2)促进急性胸痛患者的主动脉夹层诊断；(3)帮助我们个体化治疗。主动脉扩张由多种机制引起，包括遗传性结缔组织疾病，如马凡氏综合征（MFS）。在目前的提案中，我们将使用MFS作为主动脉疾病的模型，因为我们已经表明，对这种疾病的全面了解可以更好地理解血管壁生物学，并确定与主动脉瘤和夹层相关的途径。2006年，我们在MFS小鼠模型中发现过量的TGFbeta信号在MFS的发病机制中起主要作用。通过从头发现已经确定了几个候选标记，其中一个是tgf - β。我们可以证明，用氯沙坦（一种at1拮抗剂）阻断小鼠的tgf - β通路，可以使主动脉壁结构正常化。我们最近证明，小鼠模型中的循环tgf - β水平明显高于野生型小鼠。此外，服用氯沙坦可降低循环tgf - β水平。最近发表的结果表明，在儿科人群的标准治疗中加入氯沙坦可显著降低主动脉生长速度。约翰霍普金斯大学是GenTAC注册中心的一部分，该中心招收了来自广泛的遗传性疾病的主动脉瘤患者。最近，我们获得许可，对登记在册的首批207名MFS患者的tgf - β水平进行分析，结果显示，与对照组患者相比，tgf - β水平有了非常显著的提高。在目前的提案中，我们将（目标1）继续我们在MFS小鼠模型中的发现工作，并使用免疫测定和MRM（一种基于质谱的突破性技术，允许独立于抗体的定量）在小鼠和GenTAC群体中验证我们的候选标记物。在第二步（目的2）中，我们建立了小鼠急性主动脉夹层模型。这将使我们能够将从头发现扩展到急性环境，并弥合与急性夹层患者生物标志物发现的差距。我们将使用免疫分析和MRM验证我们的候选标记物，从而进一步了解主动脉夹层的预后。由于tgf β家族已被证明在MFS的发展中发挥关键作用，我们的目标是开发一种多重检测（aim 3），能够在有限数量的样品中同时测量tgf β -1、-2和- 3。我们最近获得了测量唾液中tgf - β的能力。这可能是一个有吸引力的选择，以“筛选”患者的动脉瘤活动，并为个别患者的治疗提供指导。由于结缔组织疾病患者的主动脉疾病的许多方面，包括诊断程序和治疗措施，与非综合征背景的患者相似，因此当前项目的见解将有助于一般主动脉疾病患者的护理。每年约翰霍普金斯大学直接为马里兰州创造了100亿美元的经济活动，比2002年的70亿美元增长了43%相当于今天该州经济中每24美元中的1美元。2008年，约翰霍普金斯大学提供了4.5万个就业岗位，自2002年以来，每年创造700个新就业岗位。约翰霍普金斯大学直接或间接地为马里兰州提供了超过10万个就业岗位，占该州每29个就业岗位的1个。仅在巴尔的摩市，约翰霍普金斯大学就直接或间接地提供了6万个就业岗位，占全市就业岗位的16.7%。

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (06) "Enabling Technologies" and specific Change Topic, 06- HL-101 "Developing technologies for assessment of aortic aneurysms prone to rupture or dissection". Aortic dissection describes a tear in the wall of the main vessel in the body, the aorta. The underlying pathology is diverse and predisposing factors include aortic aneurysms and diseases of the connective tissue. This is a life-threatening event, especially if the dissection is located in the ascending part of the thoracic aorta since it may lead to global myocardial ischemia by compromising the aortic valve and blood flow through the coronary arteries. Rupture of the aorta is more rare but almost always associated with a 100% mortality. In the current proposal we address a clinically relevant and pressing need to elucidate the mechanisms that (i) would enable us to identify the patient at risk for a dissection among patients with known aortic aneurysms (ii) facilitate diagnosis of aortic dissection in the patient with acute chest pain and (iii) helps us to individualize therapy. Dilation of the aorta is caused by a multitude of mechanisms including inherited connective tissue disorders such as Marfan syndrome (MFS). We will use MFS as a model for aortic diseases in the current proposal since we have already shown that a comprehensive understanding of this disorder provides greater understanding of vascular wall biology and identifies pathways relevant to aortic aneurysms and dissection in general. In 2006, we showed that excessive TGFbeta signaling plays a major role in the pathogenesis of MFS in a mouse model for MFS. Several candidate markers have been identified by de novo discovery, with one of them being TGFbeta. We could prove that blocking the TGFbeta pathway in the mouse with losartan, an AT1-anatgonist, normalizes aortic wall architecture. We recently demonstrated that circulating TGFbeta levels in the mouse model are significantly higher than in wild-type mice. Furthermore, levels of circulating TGFbeta are decreased by administration of losartan. Recently published results of adding losartan to standard therapy in a pediatric population demonstrated a significant decrease in aortic growth rate. Johns Hopkins is part of the GenTAC registry, which enrolls patients with aortic aneurysms from a broad spectrum of heritable disorders. Recently, we obtained permission to analyze the first 207 patients with MFS enrolled in the registry for levels of TGFbeta and could demonstrate a highly significant increase compared to control patients. In the current proposal we will (Aim 1) continue our discovery work in the mouse model for MFS and validate our candidate marker in the mice as well as the GenTAC population using immunoassays and MRM, a mass spectrometry based breakthrough technology that allows for antibody-independent quantification. In a second step (Aim 2), we established an acute aortic dissection model in the mouse. This will enable us to expand de novo discovery to the acute setting and bridge the gap to biomarker discovery in the patient with acute dissection. We will validate our candidate markers using immunoassays and MRM and thereby gain further insight into prognosis of aortic dissection. As the TGFbeta family has been shown to play a key role in the development of MFS, we aim to develop a multiplex assay (Aim 3) with the ability to measure TGFbeta-1, -2 and - 3 simultaneously in a limited amount of sample. We recently gained the ability to measure TGFbeta in saliva. This might be an attractive option to "screen" patients for the activity of the aneurysm and provide guidance for the therapy in the individual patient. As many aspects of aortic disease, including diagnostic procedures and therapeutic measures, in patients with connective tissue disease are similar to those with a non-syndromatic background, insights from the current projects will contribute to the care for patients with aortic disease in general. Every year Johns Hopkins Institutions directly generate about $10 billion in economic activity in the State of Maryland, a 43% increase from the $7 billion generated in 2002 and the equivalent of one of every twenty-four dollars in the state's economy today. In 2008, Johns Hopkins Institutions provided 45,000 jobs and created 700 new jobs each year since 2002. Directly and indirectly Johns Hopkins Institutions support more than 100,000 jobs in Maryland, one of every 29 in the state. In Baltimore City alone Johns Hopkins directly and indirectly supports 60,000 jobs, or 16.7% of all City employment. PUBLIC HEALTH RELEVANCE: Acute dissections and ruptures of aortic aneurysms comprise for 1-2% of all deaths in industrialized countries. There is a pressing clinical need to find mechanisms that will (i) enable us to identify the patient at risk for a dissection among patients with known aortic aneurysms (ii) facilitate diagnosis of aortic dissection in the patient with acute chest pain and (iii) help us to individualize therapy. The current proposal will use proteomics techniques in an advanced animal model of aortic aneurysms and dissections to gain insight into these mechanisms and validate the findings in a large population of patients with aortic diseases.