基于AS病灶血流动力与微环境调控的rHDL载药系统的构建及其递药机制的研究

In our previous study, recombinant high density lipoproteins (rHDL) were used as a cardiovascular drug vehicle owing to its dual functions in atherosclerotic plaque targeting and anti-atherosclerosis effect. This project is trying to deal with the difficulties in delivery of drug into macrophages in the discrete lesions based on the pathology and formation mechanisms of atherosclerosis. A cholesterol shuttle was modified on the surface of rHDL to regulate the process of cholesterol efflux from macrophage to rHDL. Meanwhile, the encapsulated drug can be released responsively around the targeted cells and then diffuse into the macrophages. In order to meet the different requirements of particle size in long circulation, EPR effect and plaque penetration, small rHDL were reversibly crosslinked by a triggered material disassembling under the over-expressed reactive oxygen in the plaque to release rHDL with the small size. To increase the margination of carriers to the vascular wall, the physicochemical parameters of carriers, such as the shape and elastic modulus, were optimized in terms of hemodynamics and microenvironment in the lesions. Collectively, these strategies endowed rHDL with the potential of passive and active targeting abilities, as well as the biomimetic property and biocompatibility, which could further improve their targeting delivery and the synergistic efficacy of carrier and drug for anti-atherosclerosis therapy. The outcome of this research will solve the key issues restricting the targeted therapy of atherosclerosis, and supply a full，accurate and powerful evidence for further understanding of the value of rHDL as a functional drug delivery system.

根据动脉粥样硬化（AS）斑块的病理学特点和形成发展机制，针对AS斑块灶点分散、靶组织结构复杂、药物难以入胞等制约靶向递药的难点，在前期利用重组高密度脂蛋白（rHDL）特殊的生理生化功能，构建心血管药物载体，产生递药和治疗双重功效的基础上，通过在rHDL载体表面修饰胆固醇传递体，调控胆固醇外流响应过程，使药物特异性在靶细胞周围释放并扩散入胞；通过组装小尺寸rHDL，利用斑块过表达的活性氧切换粒径，以适应长循环和EPR效应与斑块穿透对载体粒径的不同需求；根据病灶血流动力和微环境特征调节载体粒径、形状及弹性模量等参数，增加载体在病灶血管壁的着边和沉积。以多种策略和技术赋予rHDL被动和主动靶向能力，充分利用载体的仿生性和安全性，进一步提高载体靶向递药及与药物治疗AS的协同作用。通过本项目研究，希望能为解决AS靶向治疗中的关键问题，进一步了解rHDL作为功能性载体的运作价值提供翔实有力的科学依据。

本项目在前期将重组高密度脂蛋白（rHDL）作为功能性载体的基础上，根据动脉粥样硬化（AS）的病理生理学特点和形成发展机制，针对斑块灶点分散、靶组织结构复杂及药物难以入胞等制约靶向递药的难点，通过在载体表面修饰胆固醇传递体，使药物特异性地在靶细胞周围释放及扩散入胞；通过组装小尺寸rHDL，利用斑块高浓度的活性氧切换粒径，以适应长循环和EPR效应与斑块穿透对载体粒径的不同需求。以多种策略和技术赋予rHDL被动和主动靶向能力，在充分发挥rHDL生理功能的同时，进一步提高载体与药物协同治疗AS的作用。 .研究结果表明，β-环糊精可作为胆固醇传递体与载药rHDL联合使用，促进巨噬/泡沫细胞内胆固醇外流的同时改善细胞药物摄取。将β-环糊精修饰到载药rHDL表面，可显著增强载药系统的胆固醇移除能力与细胞药物递送性能。透明质酸修饰赋予rHDL斑块特异性靶向能力。将β-环糊精修饰的载药rHDL（~30 nm）经透明质酸-二茂铁接枝共聚物交联，基于β-环糊精与二茂铁之间的多价主客相互作用构建大粒径组装载体（~175 nm）。组装载体在体外细胞模型和动物模型中均可有效靶向聚集到动脉粥样硬化损伤处，并响应病理微环境的活性氧，解组装释放出小粒径rHDL载体，进一步靶向病理态巨噬/泡沫细胞发挥胆固醇外流与药物递送作用，从而达到有效的抗动脉粥样硬化治疗效应。.项目研究成果如下：.1、撰写SCI论文并投稿14篇，其中发表11篇；.2、主办国内外学术交流3次，参与国内外学术交流9次。.（详见附件）