炎症微环境响应性仿HDL纳米药物的构建及其靶向治疗动脉粥样硬化研究

Atherosclerosis (AS) is the common pathological basis of many fetal cardiovascular and cerebrovascular diseases, therapeutic intervention with traditional medicine always result in poor curative effect and adverse reaction. It was demonstrated that nanoparticles (NPs) may target atherosclerotic plaques, however AS is a multifocal disease with distinctively varied molecular and cellular components in heterogeneous plaques. Consequently, treatment by either passive or active targeting based on a single molecular or cellular target is not an optimal regimen. Numerous studies has confirmed that AS is a chronic inflammatory disease characterized by abnormally higher levels of reactive oxygen species(ROS), which is involved in the whole process of atherogenesis. Previous studies have shown that ROS-responsive nanomedicine we constructed before has more better anti-atherosclerosis effect than non-responsive one. So in this project we hypothesize to construct an inflammatory responsive HDL-mimetic nanomedicine with multiple targeting ability, it consist of a hydrophobic core fabricated by an oxidation responsive material and a multi-functional surface modified by phospholipid/ apolipoprotein membrane, PEG and active targeting unit c(RGDfk). Then we want to explore the relationship of its surface composition to plaque targeting efficiency as well as physical and chemical properties, and give a comprehensive evaluation of its anti-atherosclerosis effect in vivo. This study can provide theoretical support and experimental basis for developing new nanotherapies base on microenvironmental targeting technology and bionic strategy for clinical treatment of AS.

动脉粥样硬化（AS）是诸多心脑血管疾病的共同病理改变，传统药物制剂防治AS存在疗效不佳、不良反应明显等问题。研究表明纳米释药系统可以靶向于AS斑块部位，但由于主动脉组织中不同阶段斑块所表达分子和细胞组成各异，目前采用的单一靶向策略治疗效果并不理想。大量研究证实AS的慢性炎症特征导致在其不同发展阶段均有异常升高的活性氧簇（ROS）水平，申请人前期研究表明基于ROS响应性载体构建的纳米药物治疗AS的效果显著优于非响应性对照。基于此，本项目拟以前期研究的ROS响应性材料制备疏水性纳米内核以负载抗AS药物，在其表面引入磷脂/载脂蛋白膜、聚乙二醇链和靶向单元，构建具有多重靶向性的炎症微环境响应性仿HDL纳米药物；系统研究表面分子构成对其理化性能、体外生物学效应和体内斑块靶向性的影响，同时深入评价该纳米药物防治AS的疗效；为基于微环境靶向技术和仿生策略研发AS防治药物提供理论依据和实验基础。

动脉粥样硬化因其发病部位的特殊性导致其局部递送效率不高，因此常规治疗效果不佳。随着纳米递送技术的不断优化，新型纳米制剂有望为动脉粥样硬化的治疗提供高效策略。.1.基于活性响应性材料，采用仿生策略构建具有炎症响应性功能、抗动脉粥样硬化作用的仿高密度脂蛋白( high-density lipoprotein，HDL) 纳米药物。实验结果表明通过简易纳米自组装法所制备的纳米粒为规则类球形，粒径分布均匀，平均粒径约 200 nm。体外RAW264.7 细胞对纳米粒的吞噬具有时间和剂量依赖性，且能显著抑制炎症因素刺激下细胞炎症因子的分泌和活性氧的产生( P＜0.05) ，具有明显的抗炎和抗氧化作用; mHDL NP 能明显促进细胞胆固醇外排( P＜0.05) ，且细胞外排率与细胞和 mHDL NP 孵育的时间以及 mHDL NP 的浓度具有相关性;mHDL NP 亦能显著抑制巨噬细胞泡沫化的进程。这些结果表明mHDL NP在体外具有具显著的抗动脉粥样硬化的能力，为进一步的体内疗效评价奠定基础。.2.基于酸响应性材料构建了能够用于核酸类药物靶向动脉粥样硬化斑块递送的纳米递送系统。通过纳米自助装沉淀法成功制备了纳米药物AAM NP（desirable anti-miR33 nanotherapy）以及RAAM NP(AAM NP decorated with cRGDfK)，AAM NP具有显著的斑块靶向性能，且其体内外疗效评价均显示出显著的抗AS作用，RAAM NP因表面修饰cRGDfK能够进一步增加纳米粒的斑块局部富集能力以及更为显著的抗动脉粥样硬化疗效( P＜0.05)。该研究为动脉粥样硬化的靶向治疗提供新的策略，也为核酸类药物用于靶向治疗动脉粥样硬化奠定了基础。