scholarly journals Targeting Platelet GPVI Plus rt-PA Administration but Not α2β1-Mediated Collagen Binding Protects against Ischemic Brain Damage in Mice

2019 ◽  
Vol 20 (8) ◽  
pp. 2019 ◽  
Author(s):  
Michael K. Schuhmann ◽  
Peter Kraft ◽  
Michael Bieber ◽  
Alexander M. Kollikowski ◽  
Harald Schulze ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Recombinant Tissue Plasminogen Activator ◽  
Artery Occlusion ◽  
Stroke Outcome ◽  
Platelet Surface ◽  
Glycoprotein Vi ◽  
Stroke Study ◽  
Increased Risk

Platelet collagen interactions at sites of vascular injuries predominantly involve glycoprotein VI (GPVI) and the integrin α2β1. Both proteins are primarily expressed on platelets and megakaryocytes whereas GPVI expression is also shown on endothelial and integrin α2β1 expression on epithelial cells. We recently showed that depletion of GPVI improves stroke outcome without increasing the risk of cerebral hemorrhage. Genetic variants associated with higher platelet surface integrin α2 (ITGA2) receptor levels have frequently been found to correlate with an increased risk of ischemic stroke in patients. However until now, no preclinical stroke study has addressed whether platelet integrin α2β1 contributes to the pathophysiology of ischemia/reperfusion (I/R) injury. Focal cerebral ischemia was induced in C57BL/6 and Itga2−/− mice by a 60 min transient middle cerebral artery occlusion (tMCAO). Additionally, wild-type animals were pretreated with anti-GPVI antibody (JAQ1) or Fab fragments of a function blocking antibody against integrin α2β1 (LEN/B). In anti-GPVI treated animals, intravenous (IV) recombinant tissue plasminogen activator (rt-PA) treatment was applied immediately prior to reperfusion. Stroke outcome, including infarct size and neurological scoring was determined on day 1 after tMCAO. We demonstrate that targeting the integrin α2β1 (pharmacologic; genetic) did neither reduce stroke size nor improve functional outcome on day 1 after tMCAO. In contrast, depletion of platelet GPVI prior to stroke was safe and effective, even when combined with rt-PA treatment. Our results underscore that GPVI, but not ITGA2, is a promising and safe target in the setting of ischemic stroke.

VWF-Cleaving Protease ADAMTS13 Reduces Brain Injury Following Ischemic Stroke in Mice: Essential Role for VWF in Stroke

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 259-259
Author(s):  
Bing-Qiao Zhao ◽  
Anil kumar Chauhan ◽  
Ian S. Patten ◽  
Michael Dockal ◽  
Friedrich Scheiflinger ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Essential Role ◽  
Focal Cerebral Ischemia ◽  
Infarct Volume ◽  
Recombinant Tissue Plasminogen Activator ◽  
Protective Role ◽  
Artery Occlusion ◽  
Type I ◽  
Deficient Mice

Abstract Ischemic stroke is the second leading cause of death and disability. The only approved therapy available is recombinant tissue plasminogen activator (tPA), but its use remains limited. Therefore, there is a need for an alternative drug. Platelets and their adhesion receptors play a crucial role in modulating infarct size during ischemic stroke. ADAMTS13 (A Disintegrin-like And Metalloprotease with Thrombospondin type I repeats-13) is a plasma metalloprotease that cleaves von Willebrand factor (VWF) an important adhesion molecule for platelets at sites of vascular injury. In patients, an increase in circulating levels of VWF and a decrease in ADAMTS13 activity are considered risk factors for ischemic stroke. By using genetically-modified mice we have previously shown that ADAMTS13 down regulates both thrombosis and inflammation and recombinant human ADAMTS13 down regulates platelet thrombi in injured arterioles. All these processes were dependent on VWF. We therefore hypothesize that ADAMTS13 has a protective role after ischemic stroke. In this study, we show that VWF deficiency or VWF heterozygosity in mice reduces infarct volume by two-fold after focal cerebral ischemia compared to wild-type (WT) in the middle cerebral artery occlusion (MCAO) stroke model. Furthermore, infusion of recombinant human VWF in WT mice not only accelerates thrombosis in the ferric-chloride injured artery model, but also increases infarct volume compared to vehicle-treated controls. These findings suggest an essential role of VWF in modulating infarction after stroke. We also show that ADAMTS13 deficiency in mice results in approximately 20% larger infarcts after cerebral ischemia compared to WT. The larger infarcts observed in ADAMTS13 deficient mice were due to VWF because mice deficient in both ADAMTS13 and VWF had infarct sizes similar to VWF deficient mice. Importantly, infusion of r-human ADAMTS13 immediately before reperfusion (two hour after occlusion) significantly reduced infarct volume (106.2 ± 9.7 mm3 vs 75.8 ± 6.9 mm3, P<0.05). Of note, we observed that ADAMTS13 protein was induced in the ischemic penumbra region of brain after ischemic stroke. Our findings reveal an important role for VWF in modulating infarct volume after ischemic stroke. In addition, recombinant-ADAMTS13 could become a new therapeutic agent for stroke therapy.

Protective Effect of Capparis spinosa Extract Against Focal Cerebral Ischemia-Reperfusion Injury in Rats

2021 ◽  
Vol 21 ◽  
Author(s):  
Hassan Rakhshandeh ◽  
Samira Asgharzade ◽  
Mohammad Bagher Khorrami ◽  
Fatemeh Forouzanfar
Keyword(s):  
Oxidative Stress ◽  
Ischemic Stroke ◽  
Ischemia Reperfusion Injury ◽  
Focal Cerebral Ischemia ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Public Health Problem ◽  
Artery Occlusion ◽  
Stroke Group ◽  
Capparis Spinosa

Background: Ischemic stroke is a serious public health problem. Despite extensive research focusing on the area, little is known about novel treatments. Objective: In this study, we aimed to investigate the effects of Capparis spinosa (C. spinosa) extract in the middle cerebral artery occlusion (MCAO) model of ischemic stroke. Methods: Wistar rats underwent 30-min MCAO-induced brain ischemia followed by 24 h of reperfusion. C. spinose was administrated orally once a day for 7 days before the induction of MCAO. The neurologic outcome, infarct volume (TTC staining), histological examination, and markers of oxidative stress, including total thiol content and malondialdehyde (MDA) levels, were measured 24 hr. after the termination of MCAO. Results: Pretreatment with C. spinosa, reduced neurological deficit score, histopathological alterations, and infarct volume in treated groups compared to stroke group. Furthermore, pretreatment with C. spinosa extract significantly reduced the level of MDA with concomitant increases in the levels of thiol in the brain tissues compared with the stroke group. Conclusion: Our study demonstrates that C. spinosa extract effectively protects MCAO injury through attenuation of suppressing oxidative stress.

scholarly journals Extended preclinical investigation of lactate for neuroprotection after ischemic stroke

2020 ◽  
Vol 4 (1) ◽  
pp. 2514183X2090457 ◽  
Author(s):  
Lara Buscemi ◽  
Camille Blochet ◽  
Melanie Price ◽  
Pierre J Magistretti ◽  
Hongxia Lei ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Beneficial Effect ◽  
Acute Ischemic Stroke ◽  
Ischemia Reperfusion ◽  
Combined Treatment ◽  
Recombinant Tissue Plasminogen Activator ◽  
Lesion Size ◽  
Positive Influence ◽  
Artery Occlusion

Lactate has been shown to have beneficial effect both in experimental ischemia–reperfusion models and in human acute brain injury patients. To further investigate lactate’s neuroprotective action in experimental in vivo ischemic stroke models prior to its use in clinics, we tested (1) the outcome of lactate administration on permanent ischemia and (2) its compatibility with the only currently approved drug for the treatment of acute ischemic stroke, recombinant tissue plasminogen activator (rtPA), after ischemia–reperfusion. We intravenously injected mice with 1 µmol/g sodium l-lactate 1 h or 3 h after permanent middle cerebral artery occlusion (MCAO) and looked at its effect 24 h later. We show a beneficial effect of lactate when administered 1 h after ischemia onset, reducing the lesion size and improving neurological outcome. The weaker effect observed at 3 h could be due to differences in the metabolic profiles related to damage progression. Next, we administered 0.9 mg/kg of intravenous (iv) rtPA, followed by intracerebroventricular injection of 2 µL of 100 mmol/L sodium l-lactate to treat mice subjected to 35-min transient MCAO and compared the outcome (lesion size and behavior) of the combined treatment with that of single treatments. The administration of lactate after rtPA has positive influence on the functional outcome and attenuates the deleterious effects of rtPA, although not as strongly as lactate administered alone. The present work gives a lead for patient selection in future clinical studies of treatment with inexpensive and commonly available lactate in acute ischemic stroke, namely patients not treated with rtPA but mechanical thrombectomy alone or patients without recanalization therapy.

scholarly journals Root of Angelica gigas Nakai ameliorates ischemic stroke-induced brain injury in mice through the activation of the PI3K/AKT/mTOR and MAPK pathways

2020 ◽  
Author(s):  
Se-Eun Lee ◽  
Chiyeon Lim ◽  
Suin Cho
Keyword(s):  
Ischemic Stroke ◽  
Brain Injury ◽  
Ischemia Reperfusion ◽  
Recombinant Tissue Plasminogen Activator ◽  
Mapk Signaling ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Cresyl Violet ◽  
Neuroprotective Effects ◽  
Cytoplasmic Staining ◽  
Increased Risk

Abstract Background: Ischemic stroke results in disability and increased risk of morbidity, resulting in a massive burden on patients and caregivers. Recombinant tissue plasminogen activator (r-tPA) has a limited window of opportunity for efficacy and causes side effects including hemorrhage; therefore, safer and more effective therapeutic strategies are required. In this study, the neuroprotective effects of a methanolic extract of AGR (AGmex) in ischemia/reperfusion-induced brain injury in mice were investigated. Methods: Ischemic brain injury was induced in the mice by transient occlusion of the middle cerebral artery (tMCAO) for 120 min, and the effect of AGmex on the amount of infarction was measured. Cresyl violet and hematoxylin and eosin stains were used to identify changes in the neurons, nuclei, and cytoplasm. Western blotting, immunohistochemistry, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining were used to elucidate the neuroprotective mechanism of AGmex. Results: AGmex effectively reduced the infarction volume when the mice were pre-treated at 1,000 mg/kg bw/day for two consecutive days (AGmex 1000 group). Neurons, nuclei, and cytoplasmic staining were the lowest in the MCAO group, but recovered in the AGmex 1000 group. In addition, proteins related to cell growth, differentiation, and death were up-regulated in the AGmex 1000 group. Conclusion: The major recovery mechanisms appeared to be attenuation of the mitochondrial function of Bcl-2/Bax, and activation of the PI3K/AKT/mTOR and MAPK signaling pathways in ischemic neurons.

Abstract T P247: Neuronal Sirt1 Activation Negatively Regulates Rho Kinase in Photothrombotic Stroke

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Yong-Joo Ahn ◽  
Maya Hwewon Kim ◽  
Eun-Hye Lee ◽  
Ye-Rim Kwon ◽  
Wenliang Zhong ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Signaling Pathway ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Rho Kinase ◽  
Artery Occlusion ◽  
Over Expression ◽  
Therapeutic Benefits ◽  
Infarction Volume ◽  
Photothrombotic Stroke

Background and Purpose: Sirt1 is a NAD+ dependent deacetylase that is known as one of important regulators for ischemic stroke. Because the role and mechanism of genetic sirt1 over-expression in ischemic brain injury has not yet been studied, we examined that brain-specific sirt1-overexpressing transgenic (BRASTO) mice might have significant beneficial effect in ischemic stroke through regulation of sirt1-Rho kinase (ROCK) signaling pathway. Methods: We induced a middle cerebral artery occlusion model in mice and tested the effect of resveratrol (100 mg/kg, i.p.) in ischemia/reperfusion (2h/22h) injury and tested the role and mechanism with BRASTO mice in photothrombotic stroke. Protein levels in mice brain tissue lysates were determined using western blotting. Results: Sirt1 activation by resveratrol treatment reduced infarction volume and improved neurological deficit score in transient focal cerebral ischemia. BRASTO mice did not show any obvious phenotypic abnormalities and BRASTO mice improved relative cerebral blood flow and reduced infarction volume by 68.4% compare to that of WT in photothrombotic stroke. Sirt1 over-expression in BRASTO mice was significantly increased by 4.2 fold higher than that of WT mice and Rho-kinase activity was significantly decreased by 54.6% in BRASTO mice. Conclusions: These findings indicate that neuronal specific sirt1 activation in BRASTO mice reduced infarction volume in photothrombotic stroke via down-regulation of ROCK signaling pathway. These results suggest that effect of neuronal sirt1 activation may have therapeutic benefits in ischemic stroke via ROCK signaling pathway.

scholarly journals Effect of Tetramethylpyrazine on Neuroplasticity after Transient Focal Cerebral Ischemia Reperfusion in Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Junbin Lin ◽  
Chizi Hao ◽  
Yu Gong ◽  
Ying Zhang ◽  
Ying Li ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Synaptic Cleft ◽  
Artery Occlusion ◽  
Neurological Function ◽  
Group Model ◽  
Model Group ◽  
Transient Focal Cerebral Ischemia ◽  
Transmission Electron

Tetramethylpyrazine (TMP) has been widely used in ischemic stroke in China. The regulation of neuroplasticity may underlie the recovery of some neurological functions in ischemic stroke. Middle cerebral artery occlusion (MCAO) model was established in this study. Rats were divided into three groups: sham group, model group, and TMP group. The neurological function was evaluated using modified neurological severity score (mNSS). Following the neurological function test, expression of synaptophysin (SYP) and growth-associated protein 43 (GAP-43) were analyzed through immunohistochemistry at 3 d, 7 d, 14 d, and 28 d after MCAO. Finally, the synaptic structural plasticity was investigated using transmission electron microscopy (TEM). The TMP group showed better neurological function comparing to the model group. SYP levels increased gradually in ischemic penumbra (IP) in the model group and could be enhanced by TMP treatment at 7 d, 14 d, and 28 d, whereas GAP-43 levels increased from 3 d to 7 d and thereafter decreased gradually from 14 d to 28 d in the model group, which showed no significant improvement in the TMP group. The results of TEM showed a flatter synaptic interface, a thinner postsynaptic density (PSD), and a wider synaptic cleft in the model group, and the first two alterations could be ameliorated by TMP. Then, a Pearson’s correlation test revealed mNSS markedly correlated with SYP and synaptic ultrastructures. Taken together, TMP is capable of promoting functional outcome after ischemic stroke, and the mechanisms may be partially associated with regulation of neuroplasticity.

scholarly journals Sirt1 Mediates Improvement in Cognitive Defects Induced by Focal Cerebral Ischemia Following Hyperbaric Oxygen Preconditioning in Rats

2017 ◽  
pp. 1029-1039 ◽  
Author(s):  
P. DING ◽  
D. REN ◽  
S. HE ◽  
M. HE ◽  
G. ZHANG ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Hyperbaric Oxygen ◽  
Cognitive Deficits ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Beneficial Effects ◽  
Mechanistic Basis ◽  
Hyperbaric Oxygen Preconditioning

Hyperbaric oxygen preconditioning (HBO-PC) has been proposed as a safe and practical approach for neuroprotection in ischemic stroke. However, it is not known whether HPO-PC can improve cognitive deficits induced by cerebral ischemia, and the mechanistic basis for any beneficial effects remains unclear. We addressed this in the present study using rats subjected to middle cerebral artery occlusion (MCAO) as an ischemic stroke model following HBO-PC. Cognitive function and expression of phosphorylated neurofilament heavy polypeptide (pNF-H) and doublecortin (DCX) in the hippocampus were evaluated 14 days after reperfusion and after short interfering RNA-mediated knockdown of sirtuin1 (Sirt1). HBO-PC increased pNF-H and DCX expression and mitigated cognitive deficits in MCAO rats. However, these effects were abolished by Sirt1 knockdown. Our results suggest that HBO-PC can protect the brain from injury caused by ischemia-reperfusion and that Sirt1 is a potential molecular target for therapeutic approaches designed to minimize cognitive deficits caused by cerebral ischemia.

scholarly journals Different Strokes for Different Folks: The Rich Diversity of Animal Models of Focal Cerebral Ischemia

2010 ◽  
Vol 30 (8) ◽  
pp. 1412-1431 ◽  
Author(s):  
David W Howells ◽  
Michelle J Porritt ◽  
Sarah SJ Rewell ◽  
Victoria O'Collins ◽  
Emily S Sena ◽  
...  
Keyword(s):  
Animal Model ◽  
Ischemic Stroke ◽  
Animal Models ◽  
Focal Cerebral Ischemia ◽  
Experimental Stroke ◽  
Stroke Outcome ◽  
Rich Diversity ◽  
Single Animal ◽  
The Rich ◽  
Use Of Models

No single animal model is able to encompass all of the variables known to affect human ischemic stroke. This review highlights the major strengths and weaknesses of the most commonly used animal models of acute ischemic stroke in the context of matching model and experimental aim. Particular emphasis is placed on the relationships between outcome and underlying vascular variability, physiologic control, and use of models of comorbidity. The aim is to provide, for novice and expert alike, an overview of the key controllable determinants of experimental stroke outcome to help ensure the most effective application of animal models to translational research.

scholarly journals Up-regulation of miR-499a-5p decreases cerebral ischemia/reperfusion injury by targeting PDCD4

2021 ◽  
Author(s):  
Weifeng Shan ◽  
Huifeng Ge ◽  
Bingquan Chen ◽  
Linger Huang ◽  
Shaojun Zhu ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Ischemia Reperfusion Injury ◽  
Cell Model ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Tunel Staining ◽  
Cerebral Ischemia Reperfusion

Abstract MiR-499a-5p was significantly down-regulated in degenerative tissues and correlated with apoptosis. Nonetheless, the biological function of miR-499a-5p in acute ischemic stroke has been still unclear. In this study, we found the plasma levels of miR-499a-5p were significantly down-regulated in 64 ischemic stroke patients and negatively correlated with the National Institutes of Health Stroke Scale score. Then, we constructed cerebral ischemia/reperfusion (I/R) injury in rats after middle cerebral artery occlusion and subsequent reperfusion and oxygen-glucose deprivation and reoxygenation (OGD/R) treated SH-SY5Y cell model. Transfection with miR-499a-5p mimic was accomplished by intracerebroventricular injection in the in vivo I/R injury model. We further found miR-499a-5p overexpression decreased infarct volumes and cell apoptosis in the in vivo I/R stroke model using TTC and TUNEL staining. PDCD4 was a direct target of miR-499a-5p by luciferase report assay and western blotting. Knockdown of PDCD4 reduced the infarct damage and cortical neuron apoptosis caused by I/R injury. MiR-499a-5p exerted neuroprotective roles mainly through inhibiting PDCD4-mediated apoptosis by CCK-8 assay, LDH release assay and flow cytometry analysis. These findings suggest that miR-499a-5p might represent a novel target that regulates brain injury by inhibiting PDCD4-mediating apoptosis.

Abstract T P229: Deletion of Voltage Gated Proton Channel in Microglial Cells is Neurovascular Protective After Ischemic Brain Injury

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Weiguo Li ◽  
Becca Ward ◽  
Mohammed Abdelsaid ◽  
Tianzheng Yu ◽  
Yisang Yoon ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Ischemia Reperfusion ◽  
Hemorrhagic Transformation ◽  
Artery Occlusion ◽  
Proton Channel ◽  
Ros Generation ◽  
Vascular Integrity ◽  
Voltage Gated ◽  
Underlying Mechanisms ◽  
Cerebral Artery Occlusion

Despite the failure of antioxidant treatments in clinical trials, the undoubted role of reactive oxygen species (ROS) in neurovascular damage after ischemic stroke calls for a more targeted approach. ROS production by microglia, the primary resident immune cells in the brain, is a key event of this process in ischemic stroke. Voltage gated proton channel, Hv1, is localized primarily to microglia and sustains NADPH oxidase activity. Deletion of Hv1 is neuroprotective after permanent middle cerebral artery occlusion (MCAO). We hypothesized that Hv1-mediated microglial ROS generation is also critical for vascular integrity and contributes to reperfusion injury after transient ischemic stroke. The wildtype (WT) and Hv1 knockout (KO) rats (n=4) were subjected to permanent or 3/24 h transient MCAO. The neurological deficiency, infarct, hemorrhagic transformation, and edema ratio were assessed. We found that in both permanent and transient MCAO model, KO rats develop smaller infarct, less vascular injury, edema, and hemorrhagic transformation, resulting in better short-term functional outcome. These results suggest that deletion of microglial Hv1 channel is vasculoprotective after ischemia/reperfusion and the underlying mechanisms need to be further studied.

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