Zhu Wan, Shen Fanxia, Mao Lei, Zhan Lei, Kang Shuai, Sun Zhengda, Nelson Jeffrey, Zhang Rui, Zou Dingquan, McDougall Cameron M, Lawton Michael T, Vu Thiennu H, Wu Zhijian, Scaria Abraham, Colosi Peter, Forsayeth John, Su Hua
From the Center for Cerebrovascular Research, Department of Anesthesia and Perioperative Care (W.Z., F.S., L.Z., S.K., J.N., R.Z., D.Z., H.S.), Department of Neurological Surgery (L.M., C.M.M., M.T.L., J.F.), Department of Radiology (Z.S.), and Department of Medicine (T.H.V.), University of California, San Francisco; Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, MD (Z.W.); Sanofi-Genzyme R&D Center, Framingham, MA (A.S.); and BioMarin Pharmaceutical Inc, Novato, CA (P.C.).
Stroke. 2017 May;48(5):1420-1423. doi: 10.1161/STROKEAHA.116.015713. Epub 2017 Mar 21.
Brain arteriovenous malformation (bAVM) is an important risk factor for intracranial hemorrhage. Current therapies are associated with high morbidities. Excessive vascular endothelial growth factor has been implicated in bAVM pathophysiology. Because soluble FLT1 binds to vascular endothelial growth factor with high affinity, we tested intravenous delivery of an adeno-associated viral vector serotype-9 expressing soluble FLT1 (AAV9-sFLT1) to alleviate the bAVM phenotype.
Two mouse models were used. In model 1, bAVM was induced in R26CreER; mice through global gene deletion and brain focal angiogenic stimulation; AAV2-sFLT02 (an AAV expressing a shorter form of sFLT1) was injected into the brain at the time of model induction, and AAV9-sFLT1, intravenously injected 8 weeks after. In model 2, SM22αCre; mice had a 90% occurrence of spontaneous bAVM at 5 weeks of age and 50% mortality at 6 weeks; AAV9-sFLT1 was intravenously delivered into 4- to 5-week-old mice. Tissue samples were collected 4 weeks after AAV9-sFLT1 delivery.
AAV2-sFLT02 inhibited bAVM formation, and AAV9-sFLT1 reduced abnormal vessels in model 1 (GFP versus sFLT1: 3.66±1.58/200 vessels versus 1.98±1.29, <0.05). AAV9-sFLT1 reduced the occurrence of bAVM (GFP versus sFLT1: 100% versus 36%) and mortality (GFP versus sFLT1: 57% [12/22 mice] versus 24% [4/19 mice], <0.05) in model 2. Kidney and liver function did not change significantly. Minor liver inflammation was found in 56% of AAV9-sFLT1-treated model 1 mice.
By applying a regulated mechanism to restrict sFLT1 expression to bAVM, AAV9-sFLT1 can potentially be developed into a safer therapy to reduce the bAVM severity.
脑动静脉畸形（bAVM）是颅内出血的一个重要危险因素。目前的治疗方法伴随着高发病率。过量的血管内皮生长因子与bAVM的病理生理过程有关。由于可溶性FLT1能与血管内皮生长因子高亲和力结合，我们测试了静脉注射表达可溶性FLT1的9型腺相关病毒载体（AAV9-sFLT1）以减轻bAVM表型。
使用了两种小鼠模型。在模型1中，通过全基因缺失和脑局部血管生成刺激在R26CreER；小鼠中诱导bAVM；在模型诱导时将AAV2-sFLT02（一种表达较短形式sFLT1的AAV）注入脑内，并在8周后静脉注射AAV9-sFLT1。在模型2中，SM22αCre；小鼠在5周龄时90%出现自发性bAVM，在6周龄时50%死亡；将AAV9-sFLT1静脉注射到4至5周龄的小鼠体内。在注射AAV9-sFLT1 4周后收集组织样本。
AAV2-sFLT02抑制了bAVM的形成，并且AAV9-sFLT1减少了模型1中的异常血管（绿色荧光蛋白组与sFLT1组：3.66±1.58/200条血管 对 1.98±1.29，<0.05）。AAV9-sFLT1降低了模型2中bAVM的发生率（绿色荧光蛋白组与sFLT1组：100% 对 36%）和死亡率（绿色荧光蛋白组与sFLT1组：57%[12/22只小鼠] 对 24%[4/19只小鼠]，<0.05）。肾功能和肝功能没有明显变化。在56%接受AAV9-sFLT1治疗的模型1小鼠中发现轻微肝脏炎症。
通过应用一种调控机制将sFLT1的表达限制在bAVM，AAV9-sFLT1有可能被开发成一种更安全的疗法以减轻bAVM的严重程度。
