The Angiogenesis Effect Of Human Urinary Kallidinogenase After Acute Ischemic Stroke

BackgroundSince stroke becomes a leading cause of mortality and severe disability worldwide, it is of great importance to develop effective treatments for ischemic stroke. In recent years, several studies suggested that angiogenesis at ischemic penumbra after acute ischemic stroke not only enhanced blood perfusion of ischemic lesions, but also promoted endogenous neurogenesis and finally contributed to better neurological functional recovery. Therefore, angiogenesis became an attractive potential therapeutic target for acute ischemic stroke. Human Urinary Kallidinogenase (HUK), as a category I new drug deveploped recent years, was proved to ameliorate neurological deficits and improve long-time outcome after acute ischemic stroke. But there were few studies investigating the angiogenesis effect induced by HUK after acute ischemic stroke. Ga-PRGD2 PET/CT is a molecular imaging for non-invasive assessment of angiogenesis by binding to integrin αvβ3 on activated endothelial cells of newly formed microvessels. It has been put into use among several diseases including malignant tumors and myocardial infarction. However, few researches have attempted to apply it in evaluting the angiogenesis process after ischemic stroke.ObjectiveThe aim of this study is to determine the feasibility of 68Ga-PRGD2 PET to evalute angiogenesis process in MCAO rats, and to verify roles of HUK in post-ischemic angiogenesis by the combination of molecular imaging and biological indicator.MethodMiddle cerebral artery occlusion (MCAO) model of rats were established and then divided into two groups:①HUK group:Injection with HUK for 7 and 14 days, ②Control group:Injection with 0.9% saline for 7 and 14 days. And healthy rats were injected with saline as sham group. Following tests were performed for HUK and control group: ①Longa Score was performed at 1st,3rd,7th and 14th day; ②18F-FDG and 68Ga-PRGD2 MicroPET were performed at 7th and 14th day; ③Integrin β3 level of brain tissue was tested by Western Blot; ④VEGF-A level of brain tissue was tested by ELISA of HUK, control and sham group.Result1. HUK group rats may achieve better neurological functional recovery at 14th day but was not with fully significance (P=0.06);2. Distinct 18F-FDG uptake defect was seen in both HUK and control group at 7th day, but improved 18F-FDG uptake was detected in HUK group at 14th day and the uptake of HUK group was higher than control group at 14th day with roughly significance (P=0.051);3. Higher uptake of 68Ga-PRGD2 was seen in HUK group than control group both at 7th day and 14th day (P<0.05), and slightly improved uptake was seen in HUK group at 14th day than 7th day (P>0.05);4. The Integrin β3 level of HUK group was higher than control group at 7th day (P< 0.05), but there was no significant difference between HUK group and control group at 14th day (P>0.05);5. The VEGF-A level of HUK group was higher than control group both at 7th day and 14th day (P<0.05).Conclusion1. HUK treatment promotes post-ischemic angiogenesis in MCAO rats, and may be able to improve neurological functional recovery in MCAO rats;2.68Ga-PRGD2 has a value in evaluating angiogenesis process and its spatial distribution in MCAO rats.