基于血管细胞黏附分子-1单链抗体为靶点的动脉粥样斑块多模式分子显像的实验研究

Conventional imaging techniques may contribute to evaluation of artery stenotic degree and plaque morphology, etc., providing objective basis for clinical diagnosis and treatment of atherosclerosis. However, these evaluations which reflect the final effects in disease biological changes can't effectively reflect and predict the progress and changes in disease. Therefore conventional imaging techniques don't meet clinical additional needs for predicting disease occurrence, direction for individual therapy, and efficacy evaluation of new drugs..In this study, vascular cell adhesion molecule-1 (VCAM-1), which is high-expressing in unstable artery atherosclerosis (AS) plaques and plays important role in the formation of unstable plaques, is selected as a target, single-chain anti-VCAM-1 antibody will be obtained by genetic engineering technology and labeled with radionuclide 18F and quantum dot CdSe/ZnS, the stability of mouse artery AS plaques will be evaluated by radioimmunoimaging with high specificity and Quantum Dots imaging which has excellent blood vessel display, to know the location of the disease and analyze qualitatively and quantitatively. The dual-mode imaging results will be analyzed together with the in vitro results, such as immunohistochemistry, the quantity of macrophages and smooth muscle cells. This study will provide a brand new multi-modal molecular imaging technology for non-invasive and early detection of vulnerable plaques, direction of individual treatment, studying the incidence and development mechanisms of AS, and evaluation of a new drug efficacy.

传统的影像学技术在评价血管狭窄程度、斑块形态等方面具有重要的价值，为临床诊断和治疗动脉粥样硬化（AS）提供了较好的客观依据，但这些方法反映的是病变生物学变化的最终效应，不能实时有效地反映和预测病变的生物学进程和变化，难以达到临床上预测病变发生、发展、指导个体化治疗、评价新型药物作用和疗效等诸方面要求。本研究拟以不稳定AS斑块有高表达、且在不稳定斑块形成中起重要作用的血管细胞黏附分子-1(VCAM-1)为靶点，通过基因工程技术获得VCAM-1的单链抗体，行核素18F和量子点CdSe/ZnS双标记，利用放免显像的高特异性和量子点成像优越的血管显示双模式分子影像评价鼠AS斑块的稳定性，对病灶进行定性、定位和定量分析，并与离体标本免疫组化、巨噬细胞和平滑细胞数量等结果行相关分析。为无创性早期探测易损斑块、指导个体化治疗、探讨AS斑块的发生、发展机制，评价药物疗效提供一种全新的多模式分子影像技术。

传统的影像学技术为动脉粥样硬化的临床诊断和治疗提供了较好的客观依据，但只能反映病变生物学变化的最终效应，不能实施有效地反映和预测病变的生物学进程和变化。本研究以不稳定粥样硬化斑块有高表达、且在不稳定斑块形成中其重要作用的血管细胞粘附分子-1（VCAM-1）为靶点，通过噬菌体文库筛选技术获得靶向VCAM-1的单链抗体，进行99mTc标记、68Ga标记和CY5荧光标记，并用来对粥样硬化模型的兔和小鼠进行核素SPECT显像、小动物PET显像和荧光显像，以定性、定量和定位粥样硬化斑块。将动物核素和荧光显像的结果与生物分布、磷屏放射自显影等结果相关联，并与粥样硬化斑块动脉组织所表达的VCAM-1进行相关性分析，评估以VCAM-1为靶点的单链抗体分子探针进行粥样硬化显像的有效性。本研究结果显示，核素和荧光显像可很好地显示主动脉的粥样硬化斑块部位，约在显像剂注射后2-4h获得较理想的T/B比值。模型组和对照组动物的显像结果与生物分布、磷屏自显影的结果相互印证，且与主动脉的VCAM-1表达有明显相关性。本研究达到了预定的研究目标，验证了以VCAM-1单链抗体为探针进行多模式分子影像评估粥样硬化斑块的可行性和有效性，有望为临床评估粥样硬化提供新的手段。项目资助截至目前发表SCI期刊论文1篇，中文期刊论文4篇，已接收待发表论文1篇。培养硕士生2名，博士生2名，其中2名硕士已取得学位，2名博士在读。项目投入经费56万元，支出58万元，下拨经费已经使用完，还有15万元经费待拨（经核实在大学没有拨到医院），剩余经费将继续用于本课题进一步深入的实验研究，各项支出与预算基本相符。