新型载药纳米探针的构建及其针对易损斑块的靶向治疗

Vulnerable plaques constitute the essential cause for most acute cardiovascular events. Statins are considered most sufficiently substantiated among others, in an evidence-based medicine point of view. However, statins present with low bioavailability if orally taken. When aiming to achieve the stability and reversal of plaques by means of oral therapy of high-dose statins, patients suffer from the potential risk of a higher incidence of adverse drug reactions. The project attempts, with macrophages in vulnerable plaques targeted, to construct nanoparticle with liposome as carriers, atorvastatins loaded in the interior lumen, and specific nonapeptide (LyP-1) as targeting molecules. These nanoparticles are thus intended to actively target and accumulate both on the surface and inside of activated macrophages with great efficacy, releasing drugs inside vulnerable plaques, thereby realizing the goal of active targeted therapy of vulnerable plaques. Assess the targeting efficiency and intake capability of nanoparticle via in-vitro tests. Establish the ApoE -/- mice model of atherosclerosis to observe the targeted release of statins and evaluate the pharmacodynamics. This study purposes itself, through a cross-study of multi-fields and multi-subjects, as in the intertwinement of basic and clinical medicine, as well as chemistry and medicine, to achieve a breakthrough in the targeted therapy of vulnerable plaques, providing new insights in the reduction of the morbidity and mortality rates of cardiovascular diseases.

易损斑块是导致大多数急性心脑血管事件的根本原因。他汀类药物是易损斑块临床治疗中循证医学证据最充分的药物。但他汀口服给药生物利用度低，且为实现稳定斑块及逆转斑块而进行大剂量他汀口服治疗，存在他汀副反应发生率升高的潜在风险。本项目拟以易损斑块中巨噬细胞为靶向，构建以脂质体为载体，阿托伐他汀负载于脂质体内腔，特异性九肽（LyP-1）靶向分子为探针的纳米器件，使其高效率地主动靶向聚集于活化的巨噬细胞表面及胞内，并释放药物于易损斑块内部，用于实现易损斑块靶向药物治疗。通过体外实验考察该纳米探针体外靶向效率和摄取能力。建立ApoE-/-小鼠易损斑块模型，观察该纳米探针体内他汀药物靶向释放及药效评价。本研究拟通过基础与临床、化学与医学紧密结合的跨领域、跨学科的交叉研究，实现易损斑块靶向治疗的突破，为降低心脑血管病的发病率和死亡率提供新思路。

项目进展顺利，通过选择脂质体作为药物的载体，利用重组的方法将卵磷脂、他汀进行分子自组装，通过调控它们的投料比例，控制纳米载体的性质，利用HPLC确定对药物的包封率，获得不具备主动靶向治疗作用的纳米微粒。采用键合方法将使易损斑块中活化巨噬细胞表面标志物受体特异性结合的多肽LyP-1 与磷脂化合物耦联，将LyP-1 磷脂衍生物通过疏水相互作用插入上述纳米载体表面，成功构建LyP-1-脂质体-SPIONs/他汀载药纳米微粒。经巨噬细胞、动脉内皮细胞、肝细胞等不同种类细胞实验证实探针具有极佳的安全性；建立ApoE-/-小鼠颈动脉易损斑块模型，采用动物实验证实该纳米微粒可以主动靶向至易损斑块。通过电镜可见药物在巨噬细胞中被吞噬，释放。研究结果显示，高浓度纳米治疗组具有显著治疗效果，可以在10天内明显逆转斑块。组织切片免疫荧光检测显示高浓度纳米治疗组可大大降低斑块中巨噬细胞的数量及多种炎症因子的表达。目前相关结果在国际心血管会议报道，并已完成SCI论文撰写，正在申报相关专利（申请号201610772691.6）。