葡萄糖基修饰pH敏感脂质体包被二氯乙酸盐靶向肺血管重构的实验研究

项目名称： 葡萄糖基修饰pH敏感脂质体包被二氯乙酸盐靶向肺血管重构的实验研究

项目编号： No.81470242

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 李冰冰

作者单位： 南京大学

项目金额： 68万元

中文摘要： 肺动脉高压发病隐匿，确诊时患者远端肺小血管退行性病变和内膜增殖病变并存。我们前期的研究证实：二氯乙酸盐(DCA) 干预对肺高压大鼠的内膜增殖没有明显作用，可能与新生内膜造成管腔狭窄，影响了DCA在目标部位的分布；DCA对处于正常或者凋亡状态的内皮细胞的促凋亡作用恶化了内皮功能障碍等因素有关。本课题我们针对肺血管内膜增殖性损伤部位HIF-1α，己糖激酶-2（HXK-2）、葡萄糖转运体-1（ GLUT-1）高表达，糖酵解增强的特征，设计相应的靶向葡萄糖头基与pH敏感脂质体连接，通过体外实验筛选出1~2个稳定的、对pH(6.5~7.0)敏感的靶向脂质体。将DCA包封在脂质体中静脉注射，通过活体示踪、高效液相色谱、免疫荧光测定DCA在大鼠不同组织分布，及对新生内膜的靶向结合能力，观察其选择性对肺血管增殖内膜部位的促凋亡作用以及对HIF-1α、HXK-2等蛋白的影响,为治疗晚期肺高压提供新的思路。

中文关键词： 肺血管重构；平滑肌细胞；脂质体；二氯乙酸盐

英文摘要： PAH is one of insidious but fatal pan-vasculopathy diseases. The degenerative status of distal pulmonary vessels co-exists with the proliferating neointimal formation in pre-capillary arterioles in patients with PAH at the advanced stage. Our previous study indicated that early intervention with dichloroacetate can effectively prevent the neointimal formation, but late intervention was incapability in reversal of proliferating intimal lesions in rats treated with monocrotaline following left pneumonectomy. The reasons can be as follows: firstly, the narrowing or occlusion of pulmonary arteriole lumens caused by neointimal lesions precludes the distribution of DCA in these injured intraacinar or preacinar vessels. Secondly, in addition to pro-apoptosis effect of DCA on proliferating intimal lesions, DCA also has detrimental effect on normal or apoptotic endothelial cells in pulmonary microvessels, which aggravates the endothelial dysfunction and leads to pulmonary remodeling. There is considerable evidence supporting that several key factors related to cellular glycolysis including HIF-1α, hexokinase-2, glucose transport-1 have been shown markedly up-regulated in the areas of intimal lesions. The glycolytic status even under normoxia of pulmonary arterial smooth muscle cells due to mitochondria dysfunction is accompanied with hyperpolarization of mitochondria membrane potential and cell apoptosis-resistance. Based on these aforementioned findings, therefore, dichloroacetate loaded glucose-modified pH sensitive liposomes were constructed in this study and the in-vitro study was applied to testify the targeting character and drug releasing efficiency at pH (6.5~7.0) in those liposomes. The biodistribution of liposomes were identified by in vivo and ex vivo nearinfrared fluorescence imaging and further analyzed quantitatively by high performance liquid chromatography and the targeted conjunction of liposomes with neointimal lesion areas in rats was evaluated with confocal laser scanning microscopy. Finally the selective pro-apoptosis effect of liposomes on the proliferation of neointimal formation and the underlying mechanism were also investigated.

英文关键词： pulmonary vascular remodeling;pulmonary arterial smooth muscle cell;liposome;dichloroacetate