Microfibril Fragments: Biomarkers of Aortic Disease

描述(由申请人提供)：开发评估容易破裂或夹层的主动脉瘤的技术。胸腹主动脉瘤(TAA和AAA)是威胁生命的疾病，在美国占死亡原因的第13位。对于TAAS和AAA，监测动脉瘤的大小是目前唯一用于预测择期手术的必要性和避免夹层或破裂的决定因素。然而，动脉瘤的大小并不能可靠地预测容易破裂或夹层的动脉瘤。因此，我们建议测试循环微纤维片段是否可以作为描述主动脉瘤疾病状态和进展的生物标志物。我们已经开发了独特的免疫分析方法(夹心ELISA)，可以定量检测4个纤维蛋白-1片段、3个纤维蛋白-2片段和1个纤维蛋白-4片段。这些蛋白质是主动脉弹性板微纤维结构和功能的主要贡献者。初步数据表明，使用这些分析方法来识别主动脉瘤的微纤维生物标志物轮廓是可行的。测定其他结缔组织蛋白片段(例如，I型胶原的交联末端肽和XVIII型胶原的内皮抑素结构域)的分析是基于先前从血清或尿液中分离这些片段以及随后发展的特异性免疫分析。相比之下，我们的方法依赖于单抗的精致特异性来检测到迄今尚未确定特征的片段。初步数据表明，该方法可以识别与马凡综合征(纤维蛋白-2片段72-143)和主动脉瘤(纤维蛋白-2片段48-60)相关的新的生物标志物，并可以揭示主动脉瘤的标志性生物标志物特征(纤维蛋白-1片段减少和纤维蛋白-2片段增加)。我们建议使用对人类和小鼠马凡综合征的拟议研究结果作为一个楔子，以深入了解常见类型主动脉瘤的奥秘。马凡综合征是由纤维蛋白-1基因突变引起的，约占所有胸主动脉瘤的5%。用1100个主动脉瘤患者的血浆样本(其中100个是马凡人)，我们将检验这样一种假设，即不同的纤维蛋白-1和纤维蛋白-2图谱，以及可能的纤维蛋白-4图谱，将区分TAA和AAA。我们还将使用一种新的马凡综合征小鼠模型来测试循环微纤维片段的特征是否可以预测动脉瘤何时容易夹层和破裂，并可以监测治疗方案的效果，以减缓主动脉疾病的进展。结果将量化解剖和断裂所需的循环微纤维碎片的阈值浓度。如果成功，我们的研究将对动脉瘤性疾病的医疗管理产生重大影响，并将引领该领域的新研究方向。 公共卫生相关性：对于胸、腹主动脉瘤这两种危及生命的情况，密切监测动脉瘤的大小是目前唯一可以用来确定何时介入择期手术或血管内修复以避免夹层或破裂的方法。然而，规模并不是一个可靠的预测指标，因此需要新的技术。我们建议通过测试循环微纤维片段是否可以作为生物标志物来可靠地描述和监测动脉瘤性疾病，并识别容易发生 夹层或破裂。

DESCRIPTION (provided by applicant): Develop technologies for assessment of aortic aneurysms prone to rupture or dissection. Thoracic and abdominal aortic aneurysms (TAA and AAA) are life threatening conditions that comprise the thirteenth leading cause of death in the United States. For both TAAs and AAAs, monitoring the size of the aneurysm is the only determinant currently used to project the need for elective surgery and to avoid dissection or rupture. However, the size of the aneurysm is not a reliable predictor of aneurysms that are prone to rupture or dissection. Therefore, we propose to test whether circulating microfibril fragments can serve as biomarkers to profile the status and progression of aortic aneurysmal disease. We have already developed unique immunoassays (sandwich ELISAs) that can quantitate 4 fragments of fibrillin-1, 3 fragments of fibrillin-2, and 1 fragment of fibulin-4. These proteins are the major contributors to microfibril structure and function in the aortic elastic lamellae. Preliminary data demonstrate feasibility of using these assays to identify microfibril biomarker profiles for aortic aneurysms. Assays to measure other connective tissue protein fragments (e.g., the crosslinked telopeptides of collagen I and the endostatin domain of collagen XVIII) were based on the prior isolation of the fragments from serum or urine and the subsequent development of specific immunoassays. In contrast, our approach relies upon the exquisite specificities of monoclonal antibodies to detect fragments that are so far uncharacterized. Preliminary data indicate that this approach can identify novel biomarkers associated with Marfan syndrome (fibrillin-2 fragment 72-143) and aortic aneurysm (fibrillin-2 fragment 48-60) and can reveal signature biomarker profiles of aortic aneurysm (reduced fibrillin-1 fragments and increased fibrillin-2 fragments). We propose to use results from proposed studies of human and mouse Marfan syndrome as a wedge to gain insight into the mysteries of common types of aortic aneurysms. The Marfan syndrome, caused by mutations in the gene for fibrillin-1, is responsible for around 5% of all thoracic aortic aneurysms. With 1,100 plasma samples from individuals with aortic aneurysm (100 of these are Marfan), we will test the hypothesis that distinct fibrillin-1 and fibrillin-2 profiles, and possibly fibulin-4 profiles, will distinguish TAA from AAA. We will also use a new mouse model of Marfan syndrome to test whether profiles of circulating microfibril fragments can predict when aneurysms are prone to dissection and rupture and can monitor effects of treatment protocols to attenuate aortic disease progression. Results will quantitate threshold concentrations of circulating microfibril fragments required for dissection and rupture. If successful, our studies will greatly impact the medical management of aneurysmal disease and will lead to new research directions in this area. PUBLIC HEALTH RELEVANCE: For both thoracic and abdominal aneurysms, life threatening conditions, close monitoring of aneurysm size is the only way currently available to determine when to intervene with elective surgery or endovascular repair to avoid dissection or rupture. However, size is not a reliable predictor so new technologies are needed. We propose to meet this Challenge by testing whether circulating microfibril fragments can serve as biomarkers to reliably profile and monitor aneurysmal disease and identify aneurysms that are prone to dissection or rupture.