It is very important to study the factors affecting the incidence,progress and prognosis of patients with vascular dementia.50 cases of severe middle cerebral artery stenosis or occlusion underwent endovascular treatm...It is very important to study the factors affecting the incidence,progress and prognosis of patients with vascular dementia.50 cases of severe middle cerebral artery stenosis or occlusion underwent endovascular treatment(25 cases of mild cognitive dysfunction,25 cases of moderate cognitive dysfunction)were divided into two groups,where a medical drug treatment group and a control group established with 25 cases in each group.The cognitive function of each group of patients was evaluated before operation,7 days after operation,30 days after operation,and 180 days after operation.CTP was used to compare the hemodynamic changes in patients before and after operation.The severe stenosis or occlusion of the middle cerebral artery in patients can be improved,and the intracranial blood supply of patients with poorly compensated medial cranial circulation and hypoperfusion can be restored to a certain extent.Meanwhile,improvement of cognitive function was definitive in some patients with cognitive dysfunction.To guide the formulation of treatment plans for patients with severe middle cerebral artery stenosis or occlusion.展开更多
Although bone marrow mesenchymal stem cells(BMSCs)might have therapeutic potency in ischemic stroke,the benefits are limited.The current study investigated the effects of BMSCs engineered to overexpress vascular endot...Although bone marrow mesenchymal stem cells(BMSCs)might have therapeutic potency in ischemic stroke,the benefits are limited.The current study investigated the effects of BMSCs engineered to overexpress vascular endothelial growth factor(VEGF)on behavioral defects in a rat model of transient cerebral ischemia,which was induced by middle cerebral artery occlusion.VEGF-BMSCs or control grafts were injected into the left striatum of the infarcted hemisphere 24 hours after stroke.We found that compared with the stroke-only group and the vehicle-and BMSCs-control groups,the VEGF-BMSCs treated animals displayed the largest benefits,as evidenced by attenuated behavioral defects and smaller infarct volume 7 days after stroke.Additionally,VEGF-BMSCs greatly inhibited destruction of the blood-brain barrier,increased the regeneration of blood vessels in the region of ischemic penumbra,and reducedneuronal degeneration surrounding the infarct core.Further mechanistic studies showed that among all transplant groups,VEGF-BMSCs transplantation induced the highest level of brain-derived neurotrophic factor.These results suggest that BMSCs transplantation with vascular endothelial growth factor has the potential to treat ischemic stroke with better results than are currently available.展开更多
Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many...Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many controversies. This study aimed to investigate hemodynamic changes in symptomatic leukoaraiosis using transcranial Doppler ultrasonography and the breath-holding test in a Chinese Han population, from northern China. A total of 203 patients who were diagnosed with ischemic stroke or clinical chronic progressive ischemic symptoms were enrolled in this study, including 97 males and 106 females, with an age range of 43-93 years. The severity of leukoaraiosis was evaluated according to the Fazekas grading scale, and patients were divided into four groups accordingly. Grade 0 was no leukoaraiosis, and grades I, II, and III were mild, moderate, and severe leukoaraiosis, respectively, with 44, 79, 44, and 36 cases in each group. Transcranial Doppler ultrasonography and the breath-holding test were performed. The mean blood flow velocity of the bilateral middle cerebral artery was measured and the breath-holding index was calculated. The breath holding index was correlated with leukoaraiosis severity and cognitive impairment. Patients with a low breath holding index presented poor performance in the Montreal Cognitive Assessment (MoCA) and executive function tests. That is, the lower the breath holding index, the lower the scores for the MoCA and the higher for the trail-making test Parts A and B. These results indicate that the breath-holding index is a useful parameter for the evaluation of cerebrovascular reserve impairment in patients with leukoaraiosis. In addition, the breath-holding index can reflect cognitive dysfunction, providing a new insight into the pathophysiology of leukoaraiosis. This study was approved by the Ethics Committee of the Fifth Peoples Hospital of Shenyang, China (approval No. 20160301) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800014421).展开更多
BACKGROUND： Vascular endothelial growth factor （VEGF） acts as ＂molecular bridge＂ following ischemic stroke to improve and restore blood supply and reduce infarction volume. Clinical studies have demonstrated the ...BACKGROUND： Vascular endothelial growth factor （VEGF） acts as ＂molecular bridge＂ following ischemic stroke to improve and restore blood supply and reduce infarction volume. Clinical studies have demonstrated the efficacy of Rhizoma Chuanxiong （Chuanxiong） in the treatment of ischemic cerebrovascular diseases. However, whether it promotes endogenous VEGF expression in ischemic stroke remains unknown. OBJECTIVE： To investigate the influence of Rhizoma Chuanxiong on VEGF production in vitro cultured human umbilical vein endothelial cells and on VEGF expression in ischemic cerebral tissues to explore its role in angiogenesis. DESIGN, TIME AND SETTING： In vitro basic comparison of traditional Chinese drug-containing serum pharmacology; in vivo randomized, controlled, animal experiment. This study was performed at the Medical Laboratory of West China Hospital, Sichuan University between December 2002 and April 2004. MATERIALS： Two Chinese rabbits were selected. One was intragastrically perfused with 5.8 g/kg Rhizoma Chuanxiong extract twice per day for three consecutive days to prepare Rhizoma Chuanxiong extract-containing serum. The remaining rabbit was intragastrically perfused with the same volume of normal saline twice per day for three consecutive days. Rhizoma Chuanxiong extract was provided by Beijing Traditional Chinese Medicine Research Institute, predominantly composed of ligustrazine, ligustilide, and ferulic acid. ChemiKineTM human VEGF Kit was purchased from Chemicon, USA; mouse anti-VEGF monoclonal antibody and biotin-goat anti-mouse IgG were purchased from Santa Cruz Biotechnology. Inc., USA. METHODS： （1） In vitro experiment： in vitro cultured human umbilical vein endothelial cells were separately incubated in rabbit serum with 10% Rhizoma Chuanxiong extract, normal medium without rabbit serum, and rabbit serum without Rhizoma Chuanxiong extract （blank control）. In addition, cells from the three groups were incubated under normoxia （5% CO2, 95% air） and hypoxia （1% 02, 5% CO2, 94% N2）, respectively, for 24 hours. （2） In vivo experiment： a total of 4/44 Sprague Dawley rats were selected for the sham-operated group （no occlusion）, and the remaining rats were used to establish a cerebral ischemiaJreperfusion model by suture occlusion. 32 animals with ischemia/reperfusion injury were randomly divided into treatment and model groups, with 16 rats in each group. Both groups were intraperitoneally infused with 0.58 g/kg Rhizoma Chuanxiong extract and normal saline two hours following reperfusion. The sham-operated group was administrated normal saline. Animals were treated with saline or Chuanxiong extracts （0.58 g/kg） twice per day for three consecutive days. MAIN OUTCOME MEASURES： In vitro experiment： VEGF concentration was detected in each group by enzyme-linked immunosorbent assay. In vivo experiment： behavioral alterations of rats were evaluated by neurological function scale; infarct volume was assessed by hematoxylin-eosin staining; VEGF protein expression in the infarct regions was determined by immunohistochemistry. RESULTS： （1） VEGF levels were similar between the three groups under normexic condition （P 〉 0.05）; while hypoxia induced VEGF production （P 〈 0.01 ）. VEGF levels in the drug-containing serum group were particularly higher compared with the other groups （P 〈 0.01）. （2） Compared with normal saline treatment, Rhizoma Chuanxiong extract significantly improved the neurological scale and reduced cerebral infarct volumes （P〈 0.05）. The percent of VEGF-positive cells was significantly greater than the model group （P 〈 0.05）. The sham-operated group exhibited normal neurological function, with no infarct focus. CONCLUSION： Rhizoma Chuanxiong extract-containing rabbit serum effectively promoted cultured VEGF production under hypoxia. Rhizoma Chuanxiong extract upregulated VEGF expression in the infarct region, improved neurological function, and reduced infarct size.展开更多
Endovascular surgery is advantageous in experimentally induced ischemic stroke because it causes fewer cranial traumatic lesions than invasive surgery and can closely mimic the pathophysiology in stroke patients. Howe...Endovascular surgery is advantageous in experimentally induced ischemic stroke because it causes fewer cranial traumatic lesions than invasive surgery and can closely mimic the pathophysiology in stroke patients. However, the outcomes are highly variable, which limits the accuracy of evaluations of ischemic stroke studies. In this study, eight healthy adult rhesus monkeys were randomized into two groups with four monkeys in each group： middle cerebral artery occlusion at origin segment （M1） and middle cerebral artery occlusion at M2 segment. The blood flow in the middle cerebral artery was blocked completely for 2 hours using the endovascular microcoil placement technique （1 mm × 10 cm） （undetachable）, to establish a model of cerebral ischemia. The microcoil was withdrawn and the middle cerebral artery blood flow was restored. A reversible middle cerebral artery occlusion model was identified by hematoxylin-eosin staining, digital subtraction angiography, magnetic resonance angiography, magnetic resonance imaging, and neurological evaluation. The results showed that the middle cerebral artery occlusion model was successfully established in eight adult healthy rhesus monkeys, and ischemic lesions were apparent in the brain tissue of rhesus monkeys at 24 hours after occlusion. The rhesus monkeys had symptoms of neurological deficits. Compared with the M1 occlusion group, the M2 occlusion group had lower infarction volume and higher neurological scores. These experimental findings indicate that reversible middle cerebral artery occlusion can be produced with the endovascular microcoil technique in rhesus monkeys. The M2 occluded model had less infarction and less neurological impairment, which offers the potential for application in the field of brain injury research.展开更多
Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by ...Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated hemorrhage.The mechanisms underlying exacerbated hemorrhage are not fully understood.This study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2Akita/+mice to mimic patients with diabetes undergoing delayed mechanical thrombectomy.The results showed that at as early as 2 hours after reperfusion,Ins2Akita/+mice exhibited rapid development of neurological deficits,increased infarct and hemorrhagic transformation,together with exacerbated down-regulation of tight-junction protein ZO-1 and upregulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2+/+mice.This indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion,and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after reperfusion.This observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor(VEGF)and its downstream phospho-Erk1/2 at 2 hours after reperfusion,which was suggestive of premature angiogenesis induced by early VEGF up-regulation,resulting in rapid vessel disintegration in diabetic stroke.Endoplasmic reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2Akita/+mice,which suggests that the exacerbated VEGF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic conditions.In conclusion,the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy,and diabetes-induced accelerated VEGF up-regulation is likely to underlie exacerbated hemorrhagic transformation.Thus,suppression of the VEGF pathway could be a potential approach to allow reperfusion therapy in patients with diabetic stroke beyond the current treatment window.Experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong[CULATR 3834-15(approval date January 5,2016);3977-16(approval date April 13,2016);and 4666-18(approval date March 29,2018)].展开更多
Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promo...Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.展开更多
目的:研究远隔缺血预适应(RIPC)对大鼠脑缺血模型的保护作用及分子机制。方法:30只成年雄性SD大鼠随机分为4组:假手术组(sham)、RIPC组、缺血再灌注组(MCAO/R)组、RIPC+MCAO/R组;术前通过夹闭双侧股动脉给予相应组RIPC处理,利用大脑中...目的:研究远隔缺血预适应(RIPC)对大鼠脑缺血模型的保护作用及分子机制。方法:30只成年雄性SD大鼠随机分为4组:假手术组(sham)、RIPC组、缺血再灌注组(MCAO/R)组、RIPC+MCAO/R组;术前通过夹闭双侧股动脉给予相应组RIPC处理,利用大脑中动脉栓塞再灌注法(MCAO/R)制备大鼠缺血性脑卒中模型,神经功能评分检测大鼠的神经功能,用2,3,5-三苯四唑氯(TTC)对脑切片进行染色以评估脑梗死的程度。利用real time RT-PCR检测大脑皮质中低氧诱导因子-1α(HIF-1α)和血管内皮生长因子(VEGF) mRNA的表达。结果:与MCAO/R组大鼠相比,RIPC处理组大鼠神经功能缺损症状较轻(P<0.05),脑梗死体积缩小(P<0.01),皮质中HIF-1α和VEGF mRNA的表达表达明显升高(P<0.05)。结论:RIPC处理对减轻缺血性脑卒中大鼠具有保护作用,其分子机制可能与激活HIF-1α/VEGF通路有关。展开更多
基金Clinical Study of Endovascular Treatment of Severe Middle Cerebral Artery Stenosis or Occlusion and Vascular Cognitive Impairment.Project No.:2019zc184。
文摘It is very important to study the factors affecting the incidence,progress and prognosis of patients with vascular dementia.50 cases of severe middle cerebral artery stenosis or occlusion underwent endovascular treatment(25 cases of mild cognitive dysfunction,25 cases of moderate cognitive dysfunction)were divided into two groups,where a medical drug treatment group and a control group established with 25 cases in each group.The cognitive function of each group of patients was evaluated before operation,7 days after operation,30 days after operation,and 180 days after operation.CTP was used to compare the hemodynamic changes in patients before and after operation.The severe stenosis or occlusion of the middle cerebral artery in patients can be improved,and the intracranial blood supply of patients with poorly compensated medial cranial circulation and hypoperfusion can be restored to a certain extent.Meanwhile,improvement of cognitive function was definitive in some patients with cognitive dysfunction.To guide the formulation of treatment plans for patients with severe middle cerebral artery stenosis or occlusion.
基金supported by Key Research and Development Plan of Xuzhou Science and Technology Bureau,No.KC21162(to XMZ)a grant from Jiangsu Key Laboratory of Brain Disease Bioinformationg,No.XZSYSKF2021018(to XMZ)+1 种基金Natural Science Fund for Colleges and Universities in Jiangsu Province,No.19KJB320024(to HNY)the Science and Technology Development Fund from Affiliated Hospital of Xuzhou Medical University,Nos.XYFM2021024(to XMZ),XYFM2021006(to DH).
文摘Although bone marrow mesenchymal stem cells(BMSCs)might have therapeutic potency in ischemic stroke,the benefits are limited.The current study investigated the effects of BMSCs engineered to overexpress vascular endothelial growth factor(VEGF)on behavioral defects in a rat model of transient cerebral ischemia,which was induced by middle cerebral artery occlusion.VEGF-BMSCs or control grafts were injected into the left striatum of the infarcted hemisphere 24 hours after stroke.We found that compared with the stroke-only group and the vehicle-and BMSCs-control groups,the VEGF-BMSCs treated animals displayed the largest benefits,as evidenced by attenuated behavioral defects and smaller infarct volume 7 days after stroke.Additionally,VEGF-BMSCs greatly inhibited destruction of the blood-brain barrier,increased the regeneration of blood vessels in the region of ischemic penumbra,and reducedneuronal degeneration surrounding the infarct core.Further mechanistic studies showed that among all transplant groups,VEGF-BMSCs transplantation induced the highest level of brain-derived neurotrophic factor.These results suggest that BMSCs transplantation with vascular endothelial growth factor has the potential to treat ischemic stroke with better results than are currently available.
文摘Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many controversies. This study aimed to investigate hemodynamic changes in symptomatic leukoaraiosis using transcranial Doppler ultrasonography and the breath-holding test in a Chinese Han population, from northern China. A total of 203 patients who were diagnosed with ischemic stroke or clinical chronic progressive ischemic symptoms were enrolled in this study, including 97 males and 106 females, with an age range of 43-93 years. The severity of leukoaraiosis was evaluated according to the Fazekas grading scale, and patients were divided into four groups accordingly. Grade 0 was no leukoaraiosis, and grades I, II, and III were mild, moderate, and severe leukoaraiosis, respectively, with 44, 79, 44, and 36 cases in each group. Transcranial Doppler ultrasonography and the breath-holding test were performed. The mean blood flow velocity of the bilateral middle cerebral artery was measured and the breath-holding index was calculated. The breath holding index was correlated with leukoaraiosis severity and cognitive impairment. Patients with a low breath holding index presented poor performance in the Montreal Cognitive Assessment (MoCA) and executive function tests. That is, the lower the breath holding index, the lower the scores for the MoCA and the higher for the trail-making test Parts A and B. These results indicate that the breath-holding index is a useful parameter for the evaluation of cerebrovascular reserve impairment in patients with leukoaraiosis. In addition, the breath-holding index can reflect cognitive dysfunction, providing a new insight into the pathophysiology of leukoaraiosis. This study was approved by the Ethics Committee of the Fifth Peoples Hospital of Shenyang, China (approval No. 20160301) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800014421).
基金the Major State Basic Research Development Program of China,No.G1999054402
文摘BACKGROUND： Vascular endothelial growth factor （VEGF） acts as ＂molecular bridge＂ following ischemic stroke to improve and restore blood supply and reduce infarction volume. Clinical studies have demonstrated the efficacy of Rhizoma Chuanxiong （Chuanxiong） in the treatment of ischemic cerebrovascular diseases. However, whether it promotes endogenous VEGF expression in ischemic stroke remains unknown. OBJECTIVE： To investigate the influence of Rhizoma Chuanxiong on VEGF production in vitro cultured human umbilical vein endothelial cells and on VEGF expression in ischemic cerebral tissues to explore its role in angiogenesis. DESIGN, TIME AND SETTING： In vitro basic comparison of traditional Chinese drug-containing serum pharmacology; in vivo randomized, controlled, animal experiment. This study was performed at the Medical Laboratory of West China Hospital, Sichuan University between December 2002 and April 2004. MATERIALS： Two Chinese rabbits were selected. One was intragastrically perfused with 5.8 g/kg Rhizoma Chuanxiong extract twice per day for three consecutive days to prepare Rhizoma Chuanxiong extract-containing serum. The remaining rabbit was intragastrically perfused with the same volume of normal saline twice per day for three consecutive days. Rhizoma Chuanxiong extract was provided by Beijing Traditional Chinese Medicine Research Institute, predominantly composed of ligustrazine, ligustilide, and ferulic acid. ChemiKineTM human VEGF Kit was purchased from Chemicon, USA; mouse anti-VEGF monoclonal antibody and biotin-goat anti-mouse IgG were purchased from Santa Cruz Biotechnology. Inc., USA. METHODS： （1） In vitro experiment： in vitro cultured human umbilical vein endothelial cells were separately incubated in rabbit serum with 10% Rhizoma Chuanxiong extract, normal medium without rabbit serum, and rabbit serum without Rhizoma Chuanxiong extract （blank control）. In addition, cells from the three groups were incubated under normoxia （5% CO2, 95% air） and hypoxia （1% 02, 5% CO2, 94% N2）, respectively, for 24 hours. （2） In vivo experiment： a total of 4/44 Sprague Dawley rats were selected for the sham-operated group （no occlusion）, and the remaining rats were used to establish a cerebral ischemiaJreperfusion model by suture occlusion. 32 animals with ischemia/reperfusion injury were randomly divided into treatment and model groups, with 16 rats in each group. Both groups were intraperitoneally infused with 0.58 g/kg Rhizoma Chuanxiong extract and normal saline two hours following reperfusion. The sham-operated group was administrated normal saline. Animals were treated with saline or Chuanxiong extracts （0.58 g/kg） twice per day for three consecutive days. MAIN OUTCOME MEASURES： In vitro experiment： VEGF concentration was detected in each group by enzyme-linked immunosorbent assay. In vivo experiment： behavioral alterations of rats were evaluated by neurological function scale; infarct volume was assessed by hematoxylin-eosin staining; VEGF protein expression in the infarct regions was determined by immunohistochemistry. RESULTS： （1） VEGF levels were similar between the three groups under normexic condition （P 〉 0.05）; while hypoxia induced VEGF production （P 〈 0.01 ）. VEGF levels in the drug-containing serum group were particularly higher compared with the other groups （P 〈 0.01）. （2） Compared with normal saline treatment, Rhizoma Chuanxiong extract significantly improved the neurological scale and reduced cerebral infarct volumes （P〈 0.05）. The percent of VEGF-positive cells was significantly greater than the model group （P 〈 0.05）. The sham-operated group exhibited normal neurological function, with no infarct focus. CONCLUSION： Rhizoma Chuanxiong extract-containing rabbit serum effectively promoted cultured VEGF production under hypoxia. Rhizoma Chuanxiong extract upregulated VEGF expression in the infarct region, improved neurological function, and reduced infarct size.
基金supported by grants from the National Key Basic Research Program(973 Program)of China,No.2011CB707804Beijing Municipal Science and Technology Project,No.2121100005312016
文摘Endovascular surgery is advantageous in experimentally induced ischemic stroke because it causes fewer cranial traumatic lesions than invasive surgery and can closely mimic the pathophysiology in stroke patients. However, the outcomes are highly variable, which limits the accuracy of evaluations of ischemic stroke studies. In this study, eight healthy adult rhesus monkeys were randomized into two groups with four monkeys in each group： middle cerebral artery occlusion at origin segment （M1） and middle cerebral artery occlusion at M2 segment. The blood flow in the middle cerebral artery was blocked completely for 2 hours using the endovascular microcoil placement technique （1 mm × 10 cm） （undetachable）, to establish a model of cerebral ischemia. The microcoil was withdrawn and the middle cerebral artery blood flow was restored. A reversible middle cerebral artery occlusion model was identified by hematoxylin-eosin staining, digital subtraction angiography, magnetic resonance angiography, magnetic resonance imaging, and neurological evaluation. The results showed that the middle cerebral artery occlusion model was successfully established in eight adult healthy rhesus monkeys, and ischemic lesions were apparent in the brain tissue of rhesus monkeys at 24 hours after occlusion. The rhesus monkeys had symptoms of neurological deficits. Compared with the M1 occlusion group, the M2 occlusion group had lower infarction volume and higher neurological scores. These experimental findings indicate that reversible middle cerebral artery occlusion can be produced with the endovascular microcoil technique in rhesus monkeys. The M2 occluded model had less infarction and less neurological impairment, which offers the potential for application in the field of brain injury research.
基金supported by Health and Medical Research Fund,the Food and Health Bureau,The Government of the Hong Kong Special Administrative Region(03142256)General Research Fund,Hong Kong Research Grants Council(GRF#HKU773613M)+1 种基金Seed Funding Programme for Basic Research(201811159123,201910159191)The University of Hong Kong(all to ACYL)。
文摘Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated hemorrhage.The mechanisms underlying exacerbated hemorrhage are not fully understood.This study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2Akita/+mice to mimic patients with diabetes undergoing delayed mechanical thrombectomy.The results showed that at as early as 2 hours after reperfusion,Ins2Akita/+mice exhibited rapid development of neurological deficits,increased infarct and hemorrhagic transformation,together with exacerbated down-regulation of tight-junction protein ZO-1 and upregulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2+/+mice.This indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion,and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after reperfusion.This observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor(VEGF)and its downstream phospho-Erk1/2 at 2 hours after reperfusion,which was suggestive of premature angiogenesis induced by early VEGF up-regulation,resulting in rapid vessel disintegration in diabetic stroke.Endoplasmic reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2Akita/+mice,which suggests that the exacerbated VEGF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic conditions.In conclusion,the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy,and diabetes-induced accelerated VEGF up-regulation is likely to underlie exacerbated hemorrhagic transformation.Thus,suppression of the VEGF pathway could be a potential approach to allow reperfusion therapy in patients with diabetic stroke beyond the current treatment window.Experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong[CULATR 3834-15(approval date January 5,2016);3977-16(approval date April 13,2016);and 4666-18(approval date March 29,2018)].
基金supported by the National Natural Science Foundation of China,Nos.81801169 (to LXX),82071404 (to HC),81870952 (to HMW)。
文摘Promotion of new blood vessel formation is a new strategy for treating ischemic stroke.Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke.miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model,while its effect on ischemic stroke remains elusive.In this study,we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell prolife ration and enhanced angiogenesis.In rat models of focal cerebral ischemia,ove rexpression of miR-181b reduced infarction volume,promoted angiogenesis in ischemic penumbra,and improved neurological function.We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3’-UTR of phosphatase and tensin homolog(PTEN) mRNA to induce PTEN downregulation,leading to activation of the protein kinase B(Akt) pathway,upregulated expression of vascular endothelial growth facto rs,down-regulated expression of endostatin,and promoted angiogenesis.Taken togethe r,these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stro ke through activating the PTEN/Akt signal pathway and promoting angiogenesis.
文摘目的:研究远隔缺血预适应(RIPC)对大鼠脑缺血模型的保护作用及分子机制。方法:30只成年雄性SD大鼠随机分为4组:假手术组(sham)、RIPC组、缺血再灌注组(MCAO/R)组、RIPC+MCAO/R组;术前通过夹闭双侧股动脉给予相应组RIPC处理,利用大脑中动脉栓塞再灌注法(MCAO/R)制备大鼠缺血性脑卒中模型,神经功能评分检测大鼠的神经功能,用2,3,5-三苯四唑氯(TTC)对脑切片进行染色以评估脑梗死的程度。利用real time RT-PCR检测大脑皮质中低氧诱导因子-1α(HIF-1α)和血管内皮生长因子(VEGF) mRNA的表达。结果:与MCAO/R组大鼠相比,RIPC处理组大鼠神经功能缺损症状较轻(P<0.05),脑梗死体积缩小(P<0.01),皮质中HIF-1α和VEGF mRNA的表达表达明显升高(P<0.05)。结论:RIPC处理对减轻缺血性脑卒中大鼠具有保护作用,其分子机制可能与激活HIF-1α/VEGF通路有关。
