胰高血糖素样肽-1（GLP-1）对急性缺血性卒中侧支循环的作用及机制研究

It is of significance to increase cerebral collateral circulation for improving neurological deficits and long-term prognosis in acute ischemic stroke. Recently, studies have been showed that glucagon-like peptide-1 (GLP-1) and its analogues could recover the endothelium function, promote endothelial cells proliferation and angiogenesis in coronary atherosclerotic heart disease. Cerebral vascular has their own features, the effect of GLP-1 on them is remain unclear. Our previous studies found that liraglutide as the analogue of GLP-1 could decrease the infarct volume and improve the neurological deficit in the middle cerebral artery occlusion (MCAO) rats. The preliminary results have shown that liraglutide increase the expression of vascular endothelial growth factor (VEGF) in penumbra. Since cerebral collateral circulation is one of the important factors which influences infarct size, we hypothesize that GLP-1 can improve cerebral collateral circulation by promoting secondary collateral opening and functional angiogenesis in acute ischemic stroke. Herein, MCAO models will be built in wild and Glp-1r-/- knockout mice, then treated with the GLP-1 analogues liraglutide or vehicle. Core infarct volume, cerebral perfusion, cerebral blood volume and pial collateral circulation will be measured by 9.4T/30 MR in MCAO mice. Pial collateral circulation, capillary density and blood flow velocity in penumbra will be measured by two-photon laser scanning microscopy. Oxygen-glucose deprivation (OGD) model of human brain microvascular endothelial cells (HTX240) will be built, then treated with GLP-1 and its short fragment polypeptide. Proliferation, tube-formation length, cell migration, the expressions and phosphorylation levels of VEGF、PI3K、Akt、NOS、PLCγ、Erk1/2 will be measured by Western blot, immunofluorescence, shRNA, et al. This study will explore the effects and mechanisms of GLP-1 on the cerebral collateral circulation in acute ischemic stroke, which provides the theoretical basis for GLP-1 analogues in the treatment of acute ischemic stroke.

提高急性缺血性卒中脑侧支循环对减少梗死体积及改善预后有重要意义。研究显示胰高血糖素样肽-1(GLP-1)能改善外周血管内皮功能，促进动脉扩张及毛细血管新生，但其对颅内血管的作用仍不明确。我们前期研究发现GLP-1类似物可减少MCAO大鼠梗死体积，增加缺血半暗带血管内皮生长因子表达。鉴于侧支循环是决定梗死体积的重要因素，我们假设GLP-1及其类似物可通过促进急性缺血性卒中二级侧支开放和功能性毛细血管新生改善脑侧支循环。本研究拟建立野生型和Glp-1r基因敲除小鼠MCAO线栓模型和人脑微血管内皮细胞糖氧剥夺模型，使用9.4T磁共振、双光子显微镜、sh-RNA干扰、靶向蛋白抑制剂及分子生物学技术，阐明GLP-1对急性缺血性卒中侧支循环的作用及分子机制，为临床试验和GLP-1介导的药物靶向研究提供理论依据。

提高急性缺血性卒中脑侧支循环对减少梗死体积及改善预后有重要意义。研究显示胰高血糖素样肽-1(GLP-1)能改善外周血管内皮功能，促进动脉扩张及毛细血管新生，但其对颅内血管的作用仍不明确。本研究主要研究内容为1）GLP-1类似物利拉鲁肽对小鼠MCAO模型脑灌注、软脑膜侧支开放的和功能性新生血管的影响；2）GLP-1类似物促进急性缺血性卒中软脑膜侧支开放的分子机制；3）GLP-1促进急性缺血性卒中功能性血管新生的分子机制。结果显示GLP-1类似物利拉鲁肽能改善局灶性脑缺血大鼠模型缺血半暗带血管新生，改善半暗带侧支循环；GLP-1类似物司美格鲁肽可改善局灶性脑缺血小鼠模型的认知功能障碍，其机制与减少丘脑、海马神经元凋亡，上调丘脑、海马突触相关蛋白，改善突触功能相关。基于基础研究结果，团队正进行一项多中心、随机对照临床试验《利拉鲁肽治疗急性缺血性卒中/短暂性脑缺血发作合并2型糖尿病的多中心、随机、空白对照、盲法评估临床试验》（LAMP研究），ClinicalTrials ID: NCT03948347，旨在探讨GLP-1类似物利拉鲁肽治疗伴有2型糖尿病的急性缺血性非致残性卒中和高风险TIA患者的安全性和有效性。目前已在国内启动26家分中心，入组400余例患者。结果有望优化合并2型糖尿病的急性缺血性非致残性卒中和高风险TIA患者的治疗方案。