Imaging DTH, IFN gamma responses & GA in human arteries

成像DTH， ifn - γ反应和GA在人动脉。移植物动脉硬化（GA）是心脏移植晚期移植物衰竭的主要原因。目前还不存在可靠的非侵入性检测GA的工具，特别是在其早期形式。冠状动脉造影和心肌灌注成像是常规检查，但对早期疾病的检测准确性有限。然而，检测到的新生内膜并不能预测临床病程。这个项目的总体目标是开发基于免疫发病机制的无创、核成像的早期GA检测模式。我们的方法将与项目1和项目2的假设密切相关，即TH1细胞通过ifn - γ的阐述是GA反应的有效刺激物，而ifn - γ反过来又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）的激活/增殖。我们最近建立了针对病理状态下调节膜标志物的小动物成像模型，包括小鼠动脉损伤模型。具体建议包括：(1)确定已知的，精心选择的候选靶分子的表达水平，包括CXCR3和CCR5 （T细胞），pdgf β - r， alphavβ 3和VCAM-1（内皮细胞和SMC）， IP- 10和Mig（分泌），CD4+ TH1细胞，ifn - γ激活的SMC和EC， (a)细胞培养，(b)器官培养，(c) SCID小鼠模型中人-小鼠血管移植段，(d)慢性血管排斥人类标本；(2)利用肽噬菌体展示文库和生物筛选，在体外、离体和体内选择新的潜在成像配体，将噬菌体生物筛选指导在免疫激活细胞/组织的同一光谱上；(3)对选定的配体（抗体、多肽和其他小分子）进行放射性标记，并利用放射免疫测定和放射自显影技术确定其体外和体内的药理学特性；(4)使用上述1-3中选择的有限数量的放射性示踪剂，对人动脉移植到SCID小鼠模型进行基于伽马相机的体内成像。明确的靶向成像方法将是未来以患者为基础的研究的基础。最终，检测GA早期发病特征的能力可能提供预后数据，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.