血流动力学调控人脑动静脉畸形内皮细胞表达酪氨酸激酶家族ephrinB2-EPHB4的机制研究

Brain arteriovenous malformations (bAVMs) are defined as the direct communication of arteries to abnormally tortuous and dilated veins without interposing capillaries ,they account for approximately 2% of all hemorrhage strokes. Intracranial hemorrhage (ICH) is the most severe and most common clinical presentation of bAVMs. The treatment includes surgery, endovascular treatment and radiosurgery, but some leisons were considered as untreatable. Thus, understanding the pathogenesis of AVM formation will be important for informing patient management decisions. Dynamic and some special molecules will be associated with development of bAVMs. Tyrosine kinase family ephrinB2/EPHB4 plays an important role in embryonic vascular development, especially in arterial-venous determination. The hemodynamic change will influence the expression. In this research, we hypothesis that the Tyrosine kinase family ephrinB2/EPHB4 and hemodynamic will be the important basic factors for the development of bAVMs. The Clinic bAVMs cases were divided into three group by Preoperative DSA as the hemodynamic criterion, Feeding artery ,malformation nidus and draining veins were separated during the operation with the help of intraoperative MRA navigation. Biological technique were used to test the relation of ephrinB2,EPHB4,VEGF and Notch between different group . Then we set up the primary bAVMS endothelial cell culture system, and detect the different endothelial cell presentation under the change of ephrinB2-VEGF-Notch signal transduction and different cell culture laminar shear stress. We hope the conclusion will provide the key mechanism for the development of bAVMs, and to direct future diagnostic and therapeutic strategies.

脑动静脉畸形(bAVMs)是脑内动静脉直接沟通的异常血管团，占出血性脑卒中的2%，治疗的致残率仍高，探讨脑动静脉畸形的形成机制是研究新治疗方法的重点。酪氨酸激酶家族ephrinB2/EPHB4在胚胎发育中引导循环系统的形成，血流动力学影响其表达，该家族在中枢神经系统疾病中有所表达，但其在血流动力学影响下与脑动静脉畸形的关系尚未见报道。我们认为：酪氨酸激酶家族ephrinB2/EPHB4协同血流动力学共同影响脑动静脉畸形发生发展。本课题利用术前数字减影脑血管造影术（DSA）显示的供血动脉与引流静脉出现的时间间隔作为判断脑血流动力学的指标分组，对脑动静脉畸形的三个重要组分（供血动脉、畸形团及引流静脉）进行分组分成分研究，应用分子细胞生物学，深入解析信号通路 ephrinB2-VEGF-Notch、血流动力学及脑动静脉畸形三者的密切关系,阐明调控干预分子机制，为临床治疗提供理论依据。

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，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。组织学证明其与脑动静脉畸形具有相关性。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与脑动静脉畸形的病理生理学相关,通过本课题中进行的彩色编码脑血管造影技术，发现破裂脑动静脉畸形表现为引流静脉平均通过时间延长，而脑动静脉畸形的微出血与通过畸形团的高流速有关。进一步研究高流速的血流动力学表现为脑动静脉畸形周细胞覆盖率低和周细胞的数量减少。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。