Abstract 109: Depletion of Microglia Does Not Improve Functional Outcomes in Aged Mice After Transient Focal Ischemia

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Shirley Marino Lee ◽  
Jacob Hudobenko ◽  
Juneyoung Lee ◽  
Louise McCullough ◽  
Anjali Chauhan
Keyword(s):  
Ischemic Stroke ◽  
Immune Cell ◽  
Neuronal Degeneration ◽  
Artery Occlusion ◽  
Chow Diet ◽  
Early Recovery ◽  
Aged Mice ◽  
Transient Focal Ischemia ◽  
Cerebral Artery Occlusion ◽  
Oxidative Species

Introduction: With aging, microglia acquire a dysfunctional phenotype characterized by dystrophic morphology, impaired phagocytosis, reduced motility, and an exaggerated response to injury. Microglia become pathologically activated with aging and play a detrimental role in age-associated cognitive decline and neurodegenerative diseases. Older mice exhibit a differential response to stroke and have worse outcomes despite smaller infarcts compared to young mice. Microglia from aged mice produce higher levels of reactive oxidative species and have an exaggerated inflammatory response after ischemic stroke. Hypothesis: We hypothesized that ablation of microglia would reduce the exaggerated neuroinflammatory responses in aged mice and loss of microglia would improve early recovery after ischemic stroke. Aged (18-19 months) male mice were fed a control chow diet (CD) or PLX5622 chow diet (PLXD) for 21 days. On day 22, 60-minute middle cerebral artery occlusion (MCAo) or sham surgery was performed. Twenty-four hours after MCAo, neurological deficit scores (NDS) and immunohistochemistry assessments, as well as flow cytometry, were performed. Results: There was a significant reduction in Iba1 + cells in striatum and cortex of the aged mice with PLX treatment: day 7 (p<0.05), day 14 (p<0.001), and day 21 (p<0.001) vs day 0. Twenty-four hours after MCAo, the NDS were not different between CD (3.0±0.18) and PLXD (2.92±0.21). However, an increase in infarct size was seen in the aged PLXD group compared to the aged CD group (p<0.05). After MCAo, there was an increase in infiltrating monocytes and neutrophils in both diet groups compared to their respective shams (p<0.05). However, an increase in infiltrating monocytes was observed in the PLXD MCAo vs. CD MCAo (p<0.0001) reflecting a differential monocyte response in animals without microglia. Additionally, a decrease in NeuN immunoreactivity was seen in the PLXD MCAo group compared to PLXD sham (p<0.01). GFAP + cells increased in PLXD sham group as compared to CD sham (p<0.05). Conclusions: Our results suggest that microglia are essential immune cells that surprisingly limit immune cell infiltration, decrease neuronal degeneration, and reduce neuroinflammation after ischemic stroke in aged mice.

scholarly journals Hemorrhagic Stroke Induces a Time-Dependent Upregulation of miR-150-5p and miR-181b-5p in the Bloodstream

2021 ◽  
Vol 12 ◽  
Author(s):  
Pasquale Cepparulo ◽  
Ornella Cuomo ◽  
Antonio Vinciguerra ◽  
Monica Torelli ◽  
Lucio Annunziato ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Hemorrhagic Stroke ◽  
Time Window ◽  
Recombinant Tissue Plasminogen Activator ◽  
Artery Occlusion ◽  
Blood Levels ◽  
Time Intervals ◽  
Transient Focal Ischemia ◽  
Preclinical Animal Models ◽  
Cerebral Artery Occlusion

To date, the only effective pharmacological treatment for ischemic stroke is limited to the clinical use of recombinant tissue plasminogen activator (rtPA), although endovascular therapy has also emerged as an effective treatment for acute ischemic stroke. Unfortunately, the benefit of this treatment is limited to a 4.5-h time window. Most importantly, the use of rtPA is contraindicated in the case of hemorrhagic stroke. Therefore, the identification of a reliable biomarker to distinguish hemorrhagic from ischemic stroke could provide several advantages, including an earlier diagnosis, a better treatment, and a faster decision on ruling out hemorrhage so that tPA may be administered earlier. microRNAs (miRNAs) are stable non-coding RNAs crucially involved in the downregulation of gene expression via mRNA cleavage or translational repression. In the present paper, taking advantage of three preclinical animal models of stroke, we compared the miRNA blood levels of animals subjected to permanent or transient middle cerebral artery occlusion (MCAO) or to collagenase-induced hemorrhagic stroke. Preliminarily, we examined the rat miRNome in the brain tissue of ischemic and sham-operated rats; then, we selected those miRNAs whose expression was significantly modulated after stroke to create a list of miRNAs potentially involved in stroke damage. These selected miRNAs were then evaluated at different time intervals in the blood of rats subjected to permanent or transient focal ischemia or to hemorrhagic stroke. We found that four miRNAs—miR-16-5p, miR-101a-3p, miR-218-5p, and miR-27b-3p—were significantly upregulated in the plasma of rats 3 h after permanent MCAO, whereas four other different miRNAs—miR-150-5p, let-7b-5p, let-7c-5p, and miR-181b-5p—were selectively upregulated by collagenase-induced hemorrhagic stroke. Collectively, our study identified some selective miRNAs expressed in the plasma of hemorrhagic rats and pointed out the importance of a precise time point measurement to render more reliable the use of miRNAs as stroke biomarkers.

scholarly journals Alterations of the pulmonary immunity are independent of spontaneous pneumonia in an experimental model of ischemic stroke

2019 ◽  
Author(s):  
Breanne Y. Farris ◽  
Kelly L. Monaghan ◽  
Courtney D. Amend ◽  
Wen Zheng ◽  
Heng Hu ◽  
...  
Keyword(s):  
T Cells ◽  
Ischemic Stroke ◽  
Immune Cell ◽  
Artery Occlusion ◽  
Cell Fates ◽  
Cytokines And Chemokines ◽  
Lung Infections ◽  
Pulmonary Immunity ◽  
Cerebral Artery Occlusion ◽  
The Brain

AbstractStroke-associated pneumonia (SAP) is a major cause of mortality in patients who have suffered from severe ischemic stroke. Although multi-factorial in nature, stroke-induced immunosuppression plays a key role in the development of SAP. Previous studies of focal ischemic stroke induction, using a murine model of transient middle cerebral artery occlusion (tMCAO) have shown that severe brain damage results in massive apoptosis and functional defects of lymphocytes in the spleen, thymus, and peripheral blood. However, how immune alternations in remote tissues lead to a greater susceptibility to lung infections is not well-understood. Importantly, how ischemic stroke alters immune-cell fates, and the expression of cytokines and chemokines in the lungs that directly impact pulmonary immunity, has not been characterized. We report here that ischemic stroke increases the percentage of alveolar macrophages, neutrophils, and CD11b+ dendritic cells (DCs), but reduces the percentage of CD4+ T cells, CD8+ T cells, B cells, natural killer (NK) cells, and eosinophils in the lungs. The depletion of immune cells in the lungs is not caused by apoptosis, cell infiltration to the brain, or spontaneous pneumonia following ischemic stroke as previously described, but correlates with a significant reduction in the levels of multiple chemokines in the lungs, including: CCL3, CCL4, CCL5, CCL17, CCL20, CCL22, CXCL5, CXCL9, and CXCL10. These findings suggest that ischemic stroke negatively impacts pulmonary immunity to become more susceptible for SAP development. Further investigation into the mechanisms that control pulmonary immune alternations following ischemic stroke may identify novel diagnostic or therapeutic targets for SAP.

Energy-Sensing Pathways in Ischemia: The Counterbalance Between AMPK and mTORC

2020 ◽  
Vol 25 (45) ◽  
pp. 4763-4770
Author(s):  
Angel Cespedes ◽  
Mario Villa ◽  
Irene Benito-Cuesta ◽  
Maria J. Perez-Alvarez ◽  
Lara Ordoñez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Cause Of Death ◽  
Artery Occlusion ◽  
Brain Pathology ◽  
Common Cause ◽  
Specific Analysis ◽  
Energy Sensing ◽  
Cerebral Artery Occlusion

: Stroke is an important cause of death and disability, and it is the second leading cause of death worldwide. In humans, middle cerebral artery occlusion (MCAO) is the most common cause of ischemic stroke. The damage occurs due to the lack of nutrients and oxygen contributed by the blood flow. : The present review aims to analyze to what extent the lack of each of the elements of the system leads to damage and which mechanisms are unaffected by this deficiency. We believe that the specific analysis of the effect of lack of each component could lead to the emergence of new therapeutic targets for this important brain pathology.

Cerebrolysin and Aquaporin 4 Inhibition Improve Pathological and Motor Recovery after Ischemic Stroke

2018 ◽  
Vol 17 (4) ◽  
pp. 299-308 ◽  
Author(s):  
Bogdan Catalin ◽  
Otilia-Constantina Rogoveanu ◽  
Ionica Pirici ◽  
Tudor Adrian Balseanu ◽  
Adina Stan ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Vasogenic Edema ◽  
Artery Occlusion ◽  
Aquaporin 4 ◽  
Hypertonic Solution ◽  
Water Metabolism ◽  
Scar Region ◽  
Function Preservation ◽  
Neurotropic Factor ◽  
Cerebral Artery Occlusion

Background: Edema represents one of the earliest negative markers of survival and consecutive neurological deficit following stroke. The mixture of cellular and vasogenic edema makes treating this condition complicated, and to date, there is no pathogenically oriented drug treatment for edema, which leaves parenteral administration of a hypertonic solution as the only non-surgical alternative. Objective: New insights into water metabolism in the brain have opened the way for molecular targeted treatment, with aquaporin 4 channels (AQP4) taking center stage. We aimed here to assess the effect of inhibiting AQP4 together with the administration of a neurotropic factor (Cerebrolysin) in ischemic stroke. Methods: Using a permanent medial cerebral artery occlusion rat model, we administrated a single dose of the AQP4 inhibitor TGN-020 (100 mg/kg) at 15 minutes after ischemia followed by daily Cerebrolysin dosing (5ml/kg) for seven days. Rotarod motor testing and neuropathology examinations were next performed. Results: We showed first that the combination treatment animals have a better motor function preservation at seven days after permanent ischemia. We have also identified distinct cellular contributions that represent the bases of behavior testing, such as less astrocyte scarring and a larger neuronalsurvival phenotype rate in animals treated with both compounds than in animals treated with Cerebrolysin alone or untreated animals. Conclusion: Our data show that water diffusion inhibition and Cerebrolysin administration after focal ischemic stroke reduces infarct size, leading to a higher neuronal survival in the peri-core glial scar region.

scholarly journals The Key Regulator of Necroptosis, RIP1 Kinase, Contributes to the Formation of Astrogliosis and Glial Scar in Ischemic Stroke

2021 ◽  
Author(s):  
Yong-Ming Zhu ◽  
Liang Lin ◽  
Chao Wei ◽  
Yi Guo ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Glial Scar ◽  
Scar Formation ◽  
Reactive Astrocytes ◽  
Interacting Protein ◽  
Protein Levels ◽  
Endothelial Growth Factor ◽  
Cerebral Artery Occlusion

AbstractNecroptosis initiation relies on the receptor-interacting protein 1 kinase (RIP1K). We recently reported that genetic and pharmacological inhibition of RIP1K produces protection against ischemic stroke-induced astrocytic injury. However, the role of RIP1K in ischemic stroke-induced formation of astrogliosis and glial scar remains unknown. Here, in a transient middle cerebral artery occlusion (tMCAO) rat model and an oxygen and glucose deprivation and reoxygenation (OGD/Re)-induced astrocytic injury model, we show that RIP1K was significantly elevated in the reactive astrocytes. Knockdown of RIP1K or delayed administration of RIP1K inhibitor Nec-1 down-regulated the glial scar markers, improved ischemic stroke-induced necrotic morphology and neurologic deficits, and reduced the volume of brain atrophy. Moreover, knockdown of RIP1K attenuated astrocytic cell death and proliferation and promoted neuronal axonal generation in a neuron and astrocyte co-culture system. Both vascular endothelial growth factor D (VEGF-D) and its receptor VEGFR-3 were elevated in the reactive astrocytes; simultaneously, VEGF-D was increased in the medium of astrocytes exposed to OGD/Re. Knockdown of RIP1K down-regulated VEGF-D gene and protein levels in the reactive astrocytes. Treatment with 400 ng/ml recombinant VEGF-D induced the formation of glial scar; conversely, the inhibitor of VEGFR-3 suppressed OGD/Re-induced glial scar formation. RIP3K and MLKL may be involved in glial scar formation. Taken together, these results suggest that RIP1K participates in the formation of astrogliosis and glial scar via impairment of normal astrocyte responses and enhancing the astrocytic VEGF-D/VEGFR-3 signaling pathways. Inhibition of RIP1K promotes the brain functional recovery partially via suppressing the formation of astrogliosis and glial scar. Graphical Abstract

Abstract 166: Endothelial Overexpression of LOX-1 Increases Stroke Size in vivo

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Alexander Akhmedov ◽  
Remo D Spescha ◽  
Francesco Paneni ◽  
Giovani G Camici ◽  
Thomas F Luescher
Keyword(s):  
Endothelial Cells ◽  
Ischemic Stroke ◽  
Endothelial Dysfunction ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Oxidized Ldl ◽  
Artery Occlusion ◽  
Cerebral Artery Occlusion ◽  
The Brain

Background— Stroke is one of the most common causes of death and long term disability worldwide primarily affecting the elderly population. Lectin-like oxidized LDL receptor 1 (LOX-1) is the receptor for oxidized LDL identified in endothelial cells. Binding of OxLDL to LOX-1 induces several cellular events in endothelial cells, such as activation of transcription factor NF-kB, upregulation of MCP-1, and reduction in intracellular NO. Accumulating evidence suggests that LOX-1 is involved in endothelial dysfunction, inflammation, atherogenesis, myocardial infarction, and intimal thickening after balloon catheter injury. Interestingly, a recent study demonstrated that acetylsalicylic acid (aspirin), which could prevent ischemic stroke, inhibited Ox-LDL-mediated LOX-1 expression in human coronary endothelial cells. The expression of LOX-1 was increased at a transient ischemic core site in the rat middle cerebral artery occlusion model. These data suggest that LOX-1 expression induces atherosclerosis in the brain and is the precipitating cause of ischemic stroke. Therefore, the goal of the present study was to investigate the role of endothelial LOX-1 in stroke using experimental mouse model. Methods and Results— 12-week-old male LOX-1TG generated recently in our group and wild-type (WT) mice were applied for a transient middle cerebral artery occlusion (MCAO) model to induce ischemia/reperfusion (I/R) brain injury. LOX-1TG mice developed 24h post-MCAO significantly larger infarcts in the brain compared to WT (81.51±8.84 vs. 46.41±10.13, n=7, p < 0.05) as assessed morphologically using Triphenyltetrazolium chloride (TTC) staining. Moreover, LOX-1TG showed higher neurological deficit in RotaRod (35.57±8.92 vs. 66.14±10.63, n=7, p < 0.05) and Bederson tests (2.22±0.14 vs. 1.25±0.30, n=9-12, p < 0.05) - two experimental physiological tests for neurological function. Conclusions— Thus, our data suggest that LOX-1 plays a critical role in the ischemic stroke when expressed at unphysiological levels. Such LOX-1 -associated phenotype could be due to the endothelial dysfunction. Therefore, LOX-1 may represent novel therapeutic targets for preventing ischemic stroke.

scholarly journals A Novel Model for Encephalomyosynangiosis Surgery after Middle Cerebral Artery Occlusion-Induced Stroke in Mice

2021 ◽  
Author(s):  
Mitch Paro ◽  
Daylin Gamiotea Turro ◽  
Leslie Blumenfeld ◽  
Ketan R Bulsara ◽  
Rajkumar Verma
Keyword(s):  
Ischemic Stroke ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Therapeutic Option ◽  
Treatment Options ◽  
Artery Occlusion ◽  
Novel Treatment ◽  
Graft Tissue ◽  
Cerebral Artery Occlusion

Background and Purpose: No effective treatment is available for most patients who suffer ischemic stroke. Development of novel treatment options is imperative. The brain attempts to self-heal after ischemic stroke via various mechanism mediated by restored blood circulation in affected region of brain but this process is limited by inadequate angiogenesis or neoangiogenesis. Encephalomyosynangiosis (EMS) is a neurosurgical procedure that achieves angiogenesis with low morbidity in patients with moyamoya disease, reducing risk of stroke. However, EMS, surgery has never been studied as an therapeutic option after ischemic stroke. Here we described a novel procedure and feasibility data for EMS after ischemic stroke in mice. Methods: A 60 mins of middle cerebral artery occlusion (MCAo) was used to induce ischemic stroke in mice. After 3-4 hours of MCAo onset/sham, EMS was performed. Mortality of EMS, MCAo and. MCAo+EMS mice was recorded up to 21 days after surgery. Graft tissue viability was measured using a nicotinamide adenine dinucleotide reduced tetrazolium reductase assay. Results: EMS surgery after ischemic stroke does not increase mortality compared to stroke alone. Graft muscle tissue remained viable 21 days after surgery. Conclusions: This novel protocol is effective and well-tolerated, may serve as novel platform for new angiogenesis and thus recovery after ischemic stroke. If successful in mice, EMS can a very feasible and novel treatment option for ischemic stroke in humans.

Abstract 1029: Stromelysin-1 is Critical For Intracranial Bleeding After Tissue-type plasminogen activator Treatment Of Stroke In Mice

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Yasuhiro Suzuki ◽  
Nobuo Nagai ◽  
Desire Collen ◽  
Roger Lijnen ◽  
Kazuo Umemura
Keyword(s):  
Ischemic Stroke ◽  
Plasminogen Activator ◽  
Placebo Treatment ◽  
Artery Occlusion ◽  
Intracranial Bleeding ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Mmp Inhibitor ◽  
Type Plasminogen Activator ◽  
Cerebral Artery Occlusion

Background: Tissue-type plasminogen activator (t-PA) is approved for treatment of ischemic stroke patients, but it may increase the risk of intracranial bleeding (ICB). Matrix metalloproteinases (MMPs), which can be activated through the plasminogen/plasmin system, may contribute to ICB after ischemic stroke. Objectives: To explore the contribution of plasminogen, MMP-3 and MMP-9 to ICB associated with t-PA treatment after ischemic stroke. Methods: Using a thrombotic middle cerebral artery occlusion (MCA-O) model, ICB was studied in mice with genetic deficiencies of plasminogen (Plg −/ − ), stromelysin-1 (MMP-3 −/ − ) or gelatinase B (MMP-9 −/ − ) and their corresponding wild-type (WT) littermates. t-PA (10 mg/kg) or its equivalent volume of solvent was administered intravenously 4 hours after MCA-O. The induction of MMP-3 and MMP-9 was also studied in C57BL/6 WT mice. Results: In MMP-3 +/+ WT mice given solvent, ICB was 4.3 ± 2.9 mm 3 (mean ± SD), which was significantly increased with tPA treatment to 9.7 ± 4.7 mm 3 (P<0.05), whereas ICB in MMP-3 −/ − mice was not altered by t-PA treatment (5.7 ± 2.7 mm 3 , as compared to 5.1 ± 1.8 mm 3 without tPA; n = 7–9 in each group). ICB induced by t-PA was significantly less in Plg −/ − (5.7 ± 3.9 mm 3 ) than in WT mice (8.8 ± 3.2 mm 3 , p<0.05) but ICB by t-PA in MMP-9 −/ − (8.3 ± 2.3 mm 3 ) was comparable with that in WT (8.3 ± 3.1 mm 3 ; n=8 –12 in each group). Administration of the broad-spectrum MMP inhibitor GM6001 after t-PA treatment reduced ICB significantly in MMP-3 +/+ (from 6.4 ± 1.9 mm 3 to 4.1 ± 1.9 mm 3 , p<0.05) but not in MMP-3 −/ − mice (2.2 ± 0.6 mm 3 without versus 2.9 ± 1.5 mm 3 with GM6001; n=6 – 8 in each group). MMP-3 expression was significantly enhanced at the ischemic hemisphere; with placebo treatment, it was expressed only in neurons, whereas it was upregulated in endothelial cells with t-PA treatment. Although MMP-9 expression was also significantly enhanced at the ischemic brain, the amount and the distribution were comparable in mice with and without t-PA treatment. Conclusions: Our data with gene deficient mice suggest that plasminogen and MMP-3 are relatively more important than MMP-9 for the increased ICB induced by t-PA treatment of ischemic stroke.

Sign in / Sign up

Export Citation Format

Share Document