酪氨酸激酶家族配体EphrinB2调控脑动静脉畸形血管生成的机制研究

Brain AVMs are defined as the direct communication of arteries to abnormally tortuous and dilated veins without interposing capillaries.Traditionally, they have been thought of as congenital lesions resulting from abnormal vascular development，However, many authors have suggested that they are not static congenital lesions, but are dynamic with the ability to grow, regress, and even reappear as de novo brain AVMs after complete resection or radiosurgery.Angiogenesis is defined by morphogenic changes hallmarked by ongoing "pruning" of the premature vascular plexus, the formation of new branches, and.stabilization of the definitive vessel.EphrinB2, a transmembrane ligand of EphB receptor tyrosine kinases, is specifically expressed in arteries,which promot angiogenesis.Dynamic in AVMs vivo models are a potential research area. The goal of this research is to identify the relationship between ephrinB2 and brain AVMs under the intraluminal pressure.The IHC, WESTERN-BLOT , RT-PCR and cell culture will be used for the detecting the relationship between EphrinB2,VEGF,Notch4,bAVMs and Hemodynamic change.The identification of molecular targets is critical for targeted drug treatment.

脑动静脉畸形(bAVMs)是脑内动静脉直接沟通的异常血管团，畸形团长期受高血流压力的冲击，易导致破裂出血。本课题旨在探讨脑动静脉畸形发生发展机制过程中的血管生成和重塑。酪氨酸激酶家族配体EphrinB2是循环系统发育过程中最早出现的动脉血管基因标志物，影响血管生成和重塑，调控血管内皮细胞的分化和调节血管发育的口径。故假设，EphrinB2是脑动静脉畸形血管生成的关键调控因子，而血流动力学因素可能影响其表达。本课题拟根据术中B超检测血流阻力指数分组，对动静脉畸形病人术中切除畸形血管及对照组正常标本进行体内外实验，运用RT-PCR、WESTERN-BLOT、免疫组化以及活体细胞分离和三维立体培养等实验技术，评估EphrinB2在畸形血管中的表达差异，并进一步探讨血流动力学参数、EphrinB2、VEGF及Notch4基因表达之间的关系，了解脑动静脉畸形血管生成调控过程的关键途径。

酪氨酸激酶家族配体 EphrinB2 及其受体 EPHB4 是血管发育过程的动静脉标志物，为了研究 EphrinB2 及其受体 EPHB4 与脑动静脉畸形关系，我们先从体外组织学水平证明了脑动静脉畸形内皮细胞高表达EphrinB2 和EPHB4，同时发现出血的脑动静脉畸形表达率明显高于未出血动静脉畸形，提示EphrinB2及EPHB4介导的血管形成参与破裂出血，与EphrinB2有关的T淋巴细胞也显示与脑动静脉畸形的形成密切相关。进一步我们采用蛋白组学技术构建脑动静脉畸形蛋白组学数据库，从蛋白水平提示细胞之间的相互作用如紧密连接，局部连接和间隙连接与脑动静脉畸形的相关性。为进一步进行细胞学研究，我们采用酶消化方法成功建立了脑动静脉畸形原代细胞培养方法，从而为进一步的研究分子作用通路机制提供了平台。脑动静脉瘘所表现的血流动力学特点是脑动静脉畸形发生发展的基本因素，脑动静脉畸形的血管构造提示不平衡的流入道与流出道，显著增加脑动静脉畸形出血危险（RR, 7.55; 95 % CI 1.96–29.06）；脑室旁小的动静脉畸形是出血的重要危险因素。本研究通过体内外实验及临床数据分析证明酪氨酸激酶家族配体EphrinB2和EPHB4与脑动静脉畸形的形成相关，血流动力学特点影响着临床表现，该项研究结果可能为脑动静脉畸形发生机制的研究提供一个新的方向，而体内实验还需要进一步优化。