Imaging DTH, IFN gamma responses & GA in human arteries

人动脉中DTH、IFN-γ反应和GA的成像。移植物动脉硬化（graftarteriosclerosis，GA）是心脏移植术后晚期移植物衰竭的主要原因.可靠的非侵入性工具，用于检测GA，特别是在其早期形式，目前还不存在。冠状动脉造影和心肌灌注成像是常规进行的，但对早期疾病的检测准确性有限。然而，检测到的新生内膜不能预测临床病程。该项目的总体目标是开发非侵入性的，基于核成像的模式，用于早期GA检测，基于免疫发病机制。我们的方法将与项目1和2的假设密切相关，即TH 1细胞是GA反应的有效刺激因子，通过IFN-γ的产生，进而诱导趋化因子的产生，生长因子受体的表达和平滑肌细胞（SMC）的活化/增殖。我们最近建立了小动物成像模型，其靶向病理状态下的调制膜标记物，包括小鼠动脉损伤模型。具体建议包括：（1）确定已知的、仔细选择的候选靶分子的表达水平，包括CXCR 3和CCR 5（T细胞）、PDGF β-R、α v β 3和VCAM-1（内皮细胞和SMC）、IP- 10和Mig（a）细胞培养物，（B）器官培养物，（c）SCID小鼠模型中的人-小鼠血管移植片段，和（d）慢性血管排斥的人样本;（2）使用肽噬菌体展示文库和生物淘选，在体外、离体和体内选择新的潜在成像配体，将噬菌体生物淘选导向免疫活化细胞/组织的相同谱;（3）放射性标记选择的配体（抗体、肽和其他小分子），并使用放射免疫测定和放射自显影术在体外和体内确定其药理学特性;和（4）在人动脉移植到SCID小鼠模型中，使用有限数量的上述1-3中选择的放射性示踪剂，进行基于γ照相机的体内成像。定义的靶向成像方法将成为未来基于患者的研究的基础。最终，检测GA的早期发病特征的能力可以提供预后数据，并为移植患者的治疗提供新的范例。

Imaging DTH, IFN-gamma Responses and GA in Human Arteries. Graft arteriosclerosis (GA) is the major cause of late graft failure in cardiac transplantation. Reliable non-invasive tools for the detection of GA, specifically in its early form, do not currently exist. Coronary angiography and myocardial perfusion imaging are routinely performed but have limited detection accuracy for early disease. However, the detected neointima is not predictive of the clinical course. The overall goal of this project is to develop non-invasive, nuclear imaging-based modalities for early GA detection, based upon the immunopathogenesis. Our approaches will be closely linked to the Project 1 and 2 hypotheses, that TH1 cells are potent stimulators of the GA response through the elaboration of IFN-gamma which in turn, induces chemokine production, growth factor receptor expression and smooth muscle cell (SMC) activation/proliferation. We have recently established small animal imaging models which target modulated membrane markers in pathologic states, including an arterial injury model in mice. Specific proposals now include: (1) to define expression levels of known, carefully chosen candidates target molecules, including CXCR3 and CCR5 (T cells), PDGFbeta-R, alphavbeta3 and VCAM-1 (endothelial cells and SMC), IP- 10 and Mig (secreted), on CD4+ TH1 cells, IFN-gamma activated SMC and EC, in (a) cell culture, (b) organ culture, (c) human-to-mouse vascular transplant segments in a SCID mouse model, and (d) human specimens of chronic vascular rejection; (2) to select novel potential imaging ligands using a peptide phage display library and biopanning, in vitro, ex vivo, and in vivo, directing the phage biopanning at the same spectrum of immune-activated cells/tissues; (3) to radiolabel chosen ligands (antibodies, peptides and other small molecules) and determine their pharmacologic properties both in vitro and in vivo, using radioimmunoassays and autoradiography; and (4) to perform gamma camera-based in vivo imaging in the human arterial transplant to SCID mouse model, using a limited number of radiotracers selected in 1-3, above. Defined targeted imaging approaches will be the foundation for patient-based studies in the future. Ultimately, the ability to detect early pathogenetic features of GA may provide prognostic data and generate a new paradigm for treatment of transplant patients.