PET Detection of CCR2 in Human Atherosclerosis

动脉粥样硬化的一个核心现代信条是，炎症是这一过程的关键驱动因素，并可能提供 至少部分解释了即使在对传统风险进行最佳治疗后仍观察到的过度心血管风险 各种因素。对准确地对动脉粥样硬化患者进行风险分层的成像工具的需求尚未得到满足 对他们的炎症表型进行分析，找出那些需要特定治疗的患者，然后监测其效果。 单核细胞趋化蛋白-1/C-C趋化因子受体2型(MCP-1/CCR2)轴具有特殊性 感兴趣是因为它在促炎单核细胞的招募中发挥了核心作用，通过它们的转化 促炎性巨噬细胞在动脉粥样硬化早期病变的形成和发展中起着至关重要的作用。我们 开发了一种铜-放射性标记的胞外环1逆转录病毒(ECL1I)多肽PET放射性示踪剂 目标是CCR2([64Cu]DOTA-ECL1i)。我们已经证明这种放射性示踪剂提供了灵敏和特异的检测 CCR2受体在人单核细胞系和体外人外周动脉粥样硬化中的表达 斑块并跟踪临床前动脉粥样硬化模型中的疾病进展和治疗反应。此外， 我们有初步的人类受试者PET数据表明[64Cu]DOTA-ECL1i非侵入性检测动脉粥样硬化 损伤。 我们的目标是对[64Cu]DOTA-ECL1i在人体内的成像性能进行初步评估 外周颈动脉和股动脉粥样硬化，并获得关键的生物学信息，即 为未来研究的设计奠定基础，以评估其诊断、预后分配和 对新疗法的评估。为了实现这一目标，我们将同时处理以下目标： 目的1.评价[64Cu]DOTA-ECL1i PET/MR检测CCR2单核细胞和 颈动脉或股动脉内膜切除术患者动脉粥样硬化斑块中的巨噬细胞 (CEA和FEA)：在目标1A中，我们将评估正常情况下[64Cu]DOTA-ECL1i的成像特征 志愿者(第1组)、CEA患者(第2组)和FEA患者(第3组)。成像性能将是 通过与斑块存在、大小和分期的标准磁共振读数以及与体外组织的相关性来确定 放射自显影和分子生物学方法检测CCR2含量/表达及炎症反应 分析化验。作为一个探索性的目标，我们将评估造血和 动脉粥样硬化斑块进展。在目标1B中，我们将确定该方法在患者身上的重复性 颈动脉和股动脉粥样硬化性闭塞症的非手术治疗。 目的2.体外测定人动脉粥样硬化斑块标本中CEA与FEA的关系 [64Cu]DOTA-ECL1i结合、CCR2细胞表达、免疫细胞组成、细胞因子 表达和斑块的复杂性。动脉粥样硬化瘤通常是异质性的，斑块内有不同的区域。 钙化、出血和炎症。我们将使用可变的[64Cu]DOTA-ECL1i信号定义病变类型 并使用放射自显影、多重 免疫组织化学和空间转录。作为探索性分析，我们将从 目标1A和2A与已知的外周动脉粥样硬化的共病和危险因素确定 如果有特定的患者群体更有可能具有更高或更低的CCR2斑块含量。 拟议研究的成功完成将有助于描述CCR2表达的重要性 在人类动脉粥样硬化中，特别是涉及相对研究较少的部位，如外周动脉 疾病。这些结果将为评估我们的成像的更大规模的开创性多中心研究奠定基础 无创性检测动脉粥样硬化组织中CCR2表达细胞的方法。

A central modern tenet of atherosclerosis is that inflammation is a key driver of the process, and likely provides at least a partial explanation for the excess CVD risk observed even after optimal treatment of traditional risk factors. There is a critical unmet need for imaging tools that accurately risk stratify atherosclerotic patients based on their inflammatory phenotype and identify those where a given therapy is indicated and then monitor its effect. The monocyte chemoattractant protein-1 / C-C chemokine receptor type 2 (MCP-1/CCR2) axis is of particular interest due to its central role in recruitment of pro-inflammatory monocytes which through their conversion of pro-inflammatory macrophages are crucial for early atherosclerotic lesion formation and its progression. We have developed a copper-64 radiolabeled extracellular loop 1 inverso (ECL1i) peptide PET radiotracer that targets CCR2 ([64Cu]DOTA-ECL1i). We have shown this radiotracer provides sensitive and specific detection of CCR2 receptor expression in a human monocytic cell line and ex-vivo human peripheral arterial atherosclerotic plaque and tracks disease progression and treatment response in pre-clinical atherosclerotic models. Moreover, we have initial human subject PET data to suggest [64Cu]DOTA-ECL1i noninvasively detects atherosclerotic lesions. Our objective is to perform the initial evaluation of the imaging performance of [64Cu]DOTA-ECL1i in humans with peripheral carotid and femoral arterial atherosclerosis and obtain key biological information that is foundational for the design of future studies to assess its capability for diagnosis, prognosis assignment and evaluation of new therapies. To achieve this objective we will address, in parallel, the following Aims: Aim 1. Evaluate the performance of [64Cu]DOTA-ECL1i PET/MR to detect CCR2+ monocytes and macrophages in atherosclerotic plaques from patients undergoing carotid or femoral endarterectomy (CEA and FEA): In Aim 1A we will evaluate the imaging characteristics of [64Cu]DOTA-ECL1i in normal volunteers (Group 1) and in patients undergoing CEA (Group 2) or FEA (Group 3). Imaging performance will be determined by correlation with standard MR readouts of plaque presence, size and stage and with ex-vivo tissue measurements of CCR2 content/expression and inflammation determined by autoradiography and molecular profiling assays. As an exploratory Aim we will assess the relationship between hematopoiesis and atherosclerotic plaque progression. In Aim 1B we will determine the reproducibility of this approach in patients with carotid and femoral artery atherosclerotic occlusive disease managed non-operatively. Aim 2. Determine in ex-vivo human atherosclerotic CEA and FEA plaque samples the relationship between [64Cu]DOTA-ECL1i binding, CCR2+ cellular expression, immune cell composition, cytokine expression and plaque complexity. Atheromas are often heterogeneous with areas of variable intraplaque calcification, hemorrhage, and inflammation. We will define lesion types with variable [64Cu]DOTA-ECL1i signal and characterize their cellular and molecular composition using autoradiography, multiplex immunohistochemistry and spatial transcriptomics. As an exploratory analysis, we will correlate findings from Aims 1A and 2A with known co-morbidities and risk factors for peripheral arterial atherosclerosis to determine if there are specific patient populations that are more likely to have higher or lower CCR2 plaque content. Successful completion of the proposed research will permit delineation of the importance of CCR2 expression in human atherosclerosis, particularly involving sites that are relatively understudied such as peripheral arterial disease. These results will lay the foundation for larger seminal multi-center studies to assess our imaging approach to noninvasively detect CCR2 expressing cells in human atherosclerosis.