Gene delivery using polyion complex micelle for the treatment of aortic aneurysm

(1)新型多离子复合物胶束（PCI胶束）的开发为了提高基因转移效率，我们开发了两种新型的PCI胶束。一种是加入环状RGD肽的PCI胶束。圆形RGD肽可增强PCI胶束对内皮细胞和血管平滑肌细胞的递送特异性。另一种胶束是PEG-DET，它可以促进胶束从核内体向细胞质的胞内运动（核内体逃逸）。(2)小鼠主动脉瘤模型由于基因传递到大鼠主动脉瘤需要大量的PCI胶束，我们旨在建立小鼠主动脉瘤模型。先前的研究表明，持续给药血管紧张素II可能诱导主动脉瘤的形成。我们尝试了同样的方法给小鼠血管紧张素II，但大多数情况下发生了主动脉夹层破裂。虽然我们改变给药剂量和给药时间，但小鼠模型未观察到真正的动脉瘤形成。(3)利用大鼠颈动脉新生内膜模型评估基因转移效率由于无法建立小鼠主动脉瘤模型，我们决定通过将PCI胶束传递到大鼠颈动脉新生内膜来评估其体内基因转移效率。首先，用球囊导管损伤大鼠颈动脉，诱导新内膜病变。损伤后3周，将含有标记基因DNA的PIC胶束注入动脉管腔，孵育20分钟。孵育后恢复血流，3d后检测基因表达。现在，我们正在这个模型上评估添加rgd的圆形PCI胶束的基因转移效率。

(1) Development of novel polyion complex micelles (PCI micelles)To improve gene transfer efficiency, we developed two types of novel PCI micelles. One is PCI micelle added with circular RGD peptide. Circular RGD peptide could enhance delivery specificity of PCI micelle for endothelial cell and vascular smooth muscle cell. Another micelle is PEG-DET, which could promote intracellular-movement of micelle from endosome to cytoplasm (endosomal escape).(2) Mouse model of aortic aneurysmSince large amount of PCI micelle is necessary for gene delivery to rat aortic aneurysm, we aimed to establish mouse model of aortic aneurysm. Previous studies showed that continuous administration of angiotensin II potentially induced formation of aortic aneurysm. We tried the same protocol of angiotensin II administration to mouse, but aortic rupture due to dissection occurred in most of cases. Although we changed administration dose and delivery period, no formation of true aneurism was observed in mouse model.(3) Evaluation of gene transfer efficiency using neointimal model of rat carotid arteryBecause mouse model of aortic aneurysm could not be established, we decided to evaluate in vivo gene transfer efficiency of PCI micelle by delivering to neointima of rat carotid artery. First, rat carotid artery was injured with balloon catheter to induce neointimal lesion. At 3 weeks after the injury, PIC micelle containing marker gene DNA was administrated into the arterial lumen and incubated for 20 minutes. After the incubation, blood flow was resumed, and 3days later, gene expression was evaluated. Now, we are evaluating gene transfer efficiency of circular RGD-added PCI micelle on this model.