MR可视化辛伐他汀和siRNA联合靶向治疗肝移植缺血再灌注损伤

There is no effective diagnostic and therapeutic method for the ischemia-reperfusion injury after liver transplantation now. In order to realize the high sensitive monitor and synergistic treatment for IRI, this paper will develop a new microsize and long-circulating multifunctional targeted MRI contrast agents to convey the simvastatin which induce the expression of Heme oxygenase-1(HO-1) gene in IRI region and siRNA which suppresses the expression of HO-1 suppressor gene (Bach-l). At first, the monoclonal antibodies of E-selectin expressed in the IRI endothelial cells are embedded in the surface structure of polymeric micelles to realize the specific aggregation and active targeted transportation. Secondly, the acid-sensing design of carriers makes it possible that the drugs won't be released until the nanopolymer gets into the cells. Intelligent controlled release of simvastatin and siRNA can lead to the up-regulation of HO-1 and synergistic therapeutic of IRI. At the same time, the SPIO embedded in micelle can cause the specific signal changes of MRI imaging in injury location and during the transportational process to realize the synergistic diagnosis and treatment of IRI. This project will create a complete new platform for the early and specific diagnosis and treatment of IRI after liver transplantation. The desired results will have a significant meaning in enhancing the diagnostic and therapeutic effect of IRI and improving the prognosis of the patients after liver transplantation.

目前肝移植缺血再灌注损伤（IRI）的诊断和治疗尚无有效方法。本项目拟制备小粒径、长循环的新型多功能MR靶向对比剂，联合传输针对IRI关键分子- - 血红素氧合酶-1（HO-1）的药物（辛伐他汀）和抑制基因Bach-l的siRNA，实现对IRI的高灵敏度MR监测和协同治疗。首先，在聚合物纳米胶束的壳表层结构中引入针对IRI部位内皮细胞表面E-selectin的单克隆抗体片段，获得对IRI组织的特异性富集和主动靶向输送；同时，通过载体的酸敏设计，使其在体内传输过程中药物不释放，进入细胞后则快速释放，智能控释辛伐他汀与Bach siRNA，上调HO-1表达，协同治疗IRI；并且，通过在胶束内包埋SPIO，使病变部位和传输过程在MR成像中出现特异性信号改变，实现IRI的同步诊断和治疗。本项目将建立肝移植术后IRI早期、特异性诊治的全新平台，预期结果对提高IRI的诊疗效果、改善肝移植预后具有重要意义。

本研究辛伐他汀是广泛应用的一种临床药物，近年来发现其具有抗氧化以及促进骨生成的功能，大大拓宽了辛伐他汀的适应症，成为疾病临床治疗领域的新研究热点。但是，辛伐他汀存在生物利用度低和诱导体内拮抗基因Bach-1和Noggin基因的表达，限制了辛伐他汀抗氧化和促进骨生成效能。本项目通过研发多功能纳米载体不仅提高辛伐他汀的生物利用度，联合输送的siRNA也可抑制Bach-1或Noggin基因的表达，从而协同提高了辛伐他汀的抗氧化和促进骨生成的作用。首先合成了酸敏性药物联合输送载体酸敏三嵌段聚合物材料（聚乙二醇-聚天冬酰二异丙基乙二胺-胆酸），聚合物自聚集形成 “核-壳”的胶束状纳米粒子，包载疏水性辛伐他汀及SPIO于其内核；最后复合针对Bach-1 或Noggin的siRNA，所形成的纳米粒子具有粒径均一、稳定性好的特点。能够同时运输辛伐他汀及siRNA，并智能控制药物的释放，使药物在细胞内快速释放出来，可协同上调HO-1 或BMP-2 mRNA及蛋白的表达，不仅实现了对细胞氧化应激损伤的药物及基因协同治疗，也实现了辛伐他汀和Noggin-siRNA协同促进骨生成，显示出该治疗方法的协同治疗优越性。此外，将SPIO包埋于纳米载体内，可通过MR实时无创监控和示踪药物的输送和治疗效果。.通过上述研究，从细胞及动物水平上证实了多功能纳米载体可实现药物及基因协同治疗的同时，实现多功能纳米载体的MR可视化，对药物进行实时、无创、动态示踪，为肝脏缺血再灌注损伤、骨缺损等疾病的治疗提供一种疗效显著的新方法、新思路。