Microfibril Fragments: Biomarkers of Aortic Disease

描述（由申请人提供）：开发评估容易破裂或剥离的主动脉瘤的技术。胸主动脉瘤和腹主动脉瘤（TAA和AAA）是危及生命的疾病，是美国第13大死亡原因。对于TAAs和AAAs，监测动脉瘤的大小是目前唯一的决定因素，用于预测是否需要择期手术，避免剥离或破裂。然而，动脉瘤的大小并不能可靠地预测动脉瘤是否容易破裂或剥离。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测定方法（夹心elisa），可以定量测定4段纤维蛋白1、3段纤维蛋白2和1段纤维蛋白4。这些蛋白是主动脉弹性薄片中微纤维结构和功能的主要贡献者。初步数据表明，使用这些方法鉴定主动脉瘤微纤维生物标志物谱是可行的。测定其他结缔组织蛋白片段（例如，胶原I的交联末端肽和胶原XVIII的内皮抑素结构域）的方法是基于先前从血清或尿液中分离的片段以及随后发展的特异性免疫测定。相比之下，我们的方法依赖于单克隆抗体的精致特异性来检测迄今为止尚未表征的片段。初步数据表明，该方法可以识别与马凡氏综合征（fibrin -2 fragment 72-143）和主动脉瘤（fibrin -2 fragment 48-60）相关的新生物标志物，并可以揭示主动脉瘤的标志性生物标志物谱（fibrin -1片段减少和fibrin -2片段增加）。我们建议使用拟建的人类和小鼠马凡氏综合征的研究结果作为楔子，以深入了解常见类型的主动脉瘤的奥秘。由纤原蛋白-1基因突变引起的马凡氏综合征，约占所有胸主动脉瘤的5%。通过1100份来自主动脉瘤患者的血浆样本（其中100份是马凡氏），我们将检验不同的纤维蛋白-1和纤维蛋白-2谱，可能还有纤维蛋白-4谱，我们还将使用一种新的马凡氏综合征小鼠模型来测试循环微纤维片段的谱是否可以预测动脉瘤何时容易剥离和破裂，以及是否可以监测治疗方案对减轻主动脉疾病进展的影响。结果将定量分析分离和破裂所需的循环微纤维碎片的阈值浓度。如果成功，我们的研究将极大地影响动脉瘤疾病的医学管理，并将引领该领域的新研究方向。

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.