Abstract WP95: Splenectomy Protects Aged Mice From Cerebral Injury in the Experimental Stroke Model

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Anjali Chauhan ◽  
Meaghan Roy-O’Reilly ◽  
Abdullah Mamun ◽  
Nia Harris ◽  
Javiera Bravo-Alegria ◽  
...  
Keyword(s):  
T Cells ◽  
Functional Recovery ◽  
Artery Occlusion ◽  
Cerebral Injury ◽  
Neurological Deficits ◽  
Experimental Stroke ◽  
Aged Mice ◽  
Stroke Research ◽  
New Information ◽  
The Brain

Introduction: Aging is a non-modifiable risk factor for stroke. Although aged animals tend to have smaller infarcts they have worse functional recovery after stroke, suggesting difference in mechanisms between young and aged. Splenectomy reduces infarct in animal models, but how the spleen contributes to brain injury in aged mice has not been as well studied. Hypothesis: We hypothesized that peripheral inflammation increases over the lifespan. We predicted that the detrimental effects of the spleen would be reversed by splenectomy in aged mice. Methods: Young and aged male mice were splenectomized (n= 8-9), 2 weeks prior to induction of 1 hour of middle cerebral artery occlusion. Ninety-six hours after reperfusion, behavioral and infarct area was assessed. In a separate cohort, peripheral and central immune cells were quantified by flow cytometry. Results: After stroke, there was 13.3, 17.7, 25.9 and 5.88% mortality in spleen intact young, splenecyomized young, spleen intact aged and splenctomized aged mice respectively. Splenectomy led to improved behavioral deficits in aged mice as seen by lower neurological deficits scores,(1.63 ± 0.26 Vs 2.57 ± 0.20) and reduction in number of right turns in the corner test. There was significant reduction in infarct size in the splenectomized aged mice (p<0.05) as compared to spleen-intact mice. Splenectomy in aged mice lead to reduction in the frequency of CD3CD44+ T cells. Additionally, there was significant decrease in TNF-α, IL-6, IL-4, IL-12MIP-1b and RANTES levels in the aged splenectomized aged mice as compared to spleen-intact aged mice (p<0.05). In the brain, the frequency of CD45hiCD11b+ cells was reduced in the splenectomized MCAo aged as compared to spleen-intact stroke mice (p<0.05). Conclusions: Splenectomy reduced the peripheral activation of T cells in the aged mice. Also less peripheral leukocyte infiltration was observed, which mirrored improved functional recovery and reduced infarct damage in splenectomized aged mice. Hence, this study provides new information regarding age specific peripheral immune responses and interaction with the brain after experimental stroke highlighting a need for the incorporation of aged mice in the basic stroke research. Funding: 16POST27490032

Abstract WMP45: Manipulation of the Microbiome Improves Functional Recovery After Ischemic Stroke

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Michal Jandzinski ◽  
Venugopal Venna ◽  
Anjali Chauhan ◽  
Joerg Graf ◽  
Louise D McCullough
Keyword(s):  
Functional Recovery ◽  
Artery Occlusion ◽  
Peripheral Tissues ◽  
Aged Mice ◽  
Age Related ◽  
Y Maze ◽  
Obesity Hypertension ◽  
Inflammatory Milieu ◽  
Gastro Intestinal Tract ◽  
The Brain

Background: Circulating inflammatory markers increase with age. This pro-inflammatory milieu makes the organism less capable of coping with stressors such as stroke. Age related inflammation occurs in both the brain and peripheral tissues like the gastro-intestinal tract. There is increasing recognition that commensal bacteria in the GI tract are altered with age or with germ-free housing, affecting the brain. The change occurs most notably in the ratio of two major phyla of the microbiome, the Firmicutes and Bacteroidetes . Young age is associated with a low ratio of the two but this ratio increases with age, which has been linked to many diseases including obesity, hypertension, and diabetes which are major risk factors for stroke. Hypothesis: We hypothesized that there would be age-related differences in the microbiome, and that restoration of a young microbiome would improve functional recovery in aged mice. Methods: Fecal transplants from young and aged donors were administered to recipient animals after suppression of endogenous microbial compositions through concentrated Streptomycin. This allowed for successful colonization of the gut with the newly transplanted microbiome. A transient middle cerebral artery occlusion (MCAO) was used in young (3-4 month) and aged (18-20 month) male mice 4 weeks after transplant. Functional recovery was assessed by neurological deficit scores, the hang wire test, and open field activity. The Y-maze was used to assess cognitive impairment. Results: We successfully reversed the microbiomes of aged organisms and gave young animals “aged” biomes. Animals with “aged” microbiomes prior to stroke had worsened functional recovery based on all behavioral tests. The “aged” biome increased mortality rates most notably in the young recipients which had over 50% mortality. Aged mice had significantly improved functional recovery as assessed by the HW test ( P < 0.05 ) and NDS after reconstitution of “young” microbiome prior to stroke compared to aged control animals with the normal “aged” microbiomes. Conclusion: Aged mice have high Firmicutes and Bacteroidetes relative abundances. Manipulation of the microbiome in young and aged mice is possible. Restoration of a youthful biome improved functional recovery in aged mice.

Abstract P746: Sex Differences in Cognitive and Psychological Outcomes of Stroke: Impact of Diabetes

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Victoria L Wolf ◽  
Aunay Miller ◽  
Raghavendar Chandran ◽  
Weiguo Li ◽  
Adviye Ergul
Keyword(s):  
Artery Occlusion ◽  
Psychological Outcomes ◽  
Experimental Stroke ◽  
Dark Light ◽  
Stroke Outcomes ◽  
Post Stroke ◽  
Stroke Research ◽  
Y Maze ◽  
Male Animal ◽  
The Impact

Diabetes increases risk and severity of post-stroke cognitive impairment (PSCI), a major cause of disability worldwide. While it is known that females suffer more from PSCI, psychological outcomes and underlying reasons are poorly understood. From a preclinical perspective, potential explanations include 1) use of otherwise healthy animals in experimental stroke research without integration of common comorbid diseases like diabetes into the study design, and 2) optimization of most behavioral tests for sensorimotor and cognitive functions using only male animal models. Our hypothesis is that post-stroke outcomes are sex and comorbid disease-dependent. To test this, we validated the Novel Object Recognition (NOR), Y-maze, and Passive Avoidance (PAT) behavioral paradigms in Ctrl and Diabetic (DM) male (M) and female (F) rats pre- and post-stroke (S) via 60 min. middle cerebral artery occlusion (MCAO). We tested the PAT paradigm with a multi-trial method where the animals were habituated to the dark/light chambers without foot shock and then trained in 3 trials where they received foot shock upon entering the dark. We then tested retention following MCAO for their memory of foot shock 2 weeks prior. Multitrial results suggested that there was no difference between groups in learning to associate the dark chamber with the shock, so we revised the multitrial method into a single-trial method for ongoing retention tests to compare the impact of stroke on shock memory recall. PAT revealed (Table 1) disease- and sex-dependent responses to aversive stimulus. NOR revealed that M-DM-S and F-DM-S rats have decreased exploration time, suggesting that they are unmotivated or depressed. Y-maze indicated that males displayed spatial memory recovery, while females remained impaired. In summary, we have observed numerous sex- and disease-dependent post-stroke outcomes with standard behavioral paradigms, causing us to carefully consider how we evaluate preclinical outcomes.

Abstract WP118: The Flavanol (-)-Epicatechin Improves Functional Recovery In Mice Subjected To Experimental Stroke

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Christopher C Leonardo ◽  
Sean Robbins ◽  
Abdullah A Ahmad ◽  
Sylvain Dore
Keyword(s):  
Functional Recovery ◽  
Transcriptional Activation ◽  
Infarct Volume ◽  
Epidemiological Studies ◽  
Artery Occlusion ◽  
Experimental Stroke ◽  
Adhesive Tape ◽  
Dietary Consumption ◽  
Therapeutic Doses ◽  
Cerebral Artery Occlusion

Background: Epidemiological studies indicate that flavanol consumption reduces the propensity to develop cerebrovascular disease. Available data suggest actions on multiple pro-inflammatory pathways, yet it remains unclear which pathways mediate functional recovery after stroke. Our goal is to begin identifying the mechanisms by which the flavanol (-)-epicatechin (EC) improves anatomical and functional outcomes. Based upon data from initial dose-response experiments, ongoing studies are investigating hypothesized protective pathways involving matrix metalloproteinase-mediated blood brain barrier protection and Nrf2 transcriptional activation. Methods: Male, 8-10wk old C57BL/6 mice were pretreated with EC 90m prior to permanent distal middle cerebral artery occlusion. Vehicle or EC was administered by oral gavage to mimic dietary consumption. Mice were evaluated 1, 4 and 7d post-stroke for performance on various sensorimotor tasks prior to histological assessments. Results: Initial experiments demonstrated that mice treated with 15mg/kg EC showed reduced latency to remove adhesive tape at 1d compared to vehicle controls (n=12, p<0.01). Similarly, immunoreactivity for the microglia/macrophage marker Iba1 was increased in the ipsilateral hemispheres of mice 7d after treatment with vehicle (p<0.01), whereas pretreatment with 15mg/kg blocked this effect (n=4). Mice treated with 15mg/kg also showed a trend toward reduced infarct volume relative to vehicle controls (n=5-9 per group). In subsequent reduced dosing studies, vehicle-treated mice again showed deficiencies in removing adhesive tape at 1d (n=8, p<0.01). Remarkably, mice treated with 15, 10 or 5mg/kg EC showed no deficits. Similarly, vehicle control mice showed grip strength impairments up to 7d (n=8, p<0.05) that were absent in all groups of EC-treated mice. Conclusions: Preventative administration of EC promotes functional recovery in mice subjected to experimental stroke. Investigations are underway to determine the pathways mediated by EC following administration at these therapeutic doses. Together, these data will provide insights into the potential for (-)-epicatechin as a clinical therapeutic.

scholarly journals Anti-Inflammatory Effects of the 70 kDa Heat Shock Protein in Experimental Stroke

2007 ◽  
Vol 28 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Zhen Zheng ◽  
Jong Youl Kim ◽  
Hualong Ma ◽  
Jong Eun Lee ◽  
Midori A Yenari
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Brain Ischemia ◽  
Inflammatory Responses ◽  
Nuclear Factor Κb ◽  
Artery Occlusion ◽  
Brain Inflammation ◽  
Neurological Deficits ◽  
Experimental Stroke ◽  
Anti Inflammatory

The 70-kDa heat shock protein (Hsp70) is involved in protecting the brain from a variety of insults including stroke. Although the mechanism has been largely considered to be because of its chaperone functions, recent work indicates that Hsp70 also modulates inflammatory responses. To explore how and whether Hsp70 regulate immune responses in brain ischemia, mice overexpressing Hsp70 (Hsp Tg) were subjected to 2 h middle cerebral artery occlusion, followed by 24 h reperfusion. Parallel experiments were performed using a brain inflammation model. Hsp Tg microglia cocultured with astrocytes were used to evaluate the direct effects of Hsp70 on cytotoxicity of mcrigolia. Compared with wild-type (Wt) littermates, Hsp Tg mice showed decreased infarct size and improved neurological deficits. The number of activated microglia/macrophages were also reduced in ischemic brains of Hsp Tg mice. Similar observations were made in a model of brain inflammation that does not result in brain cell death. Overexpression of Hsp70 in microglia completely prevented microglia-induced cytotoxicity to astrocytes. Activation of the inflammatory transcription factor, nuclear factor-κB (NF-κB) was inhibited significantly in Hsp Tg mice and microglia. This was associated with decreased phosphorylation of NF-κB inhibitor protein, IκBα, and decreased expression of several NFκB-regulated genes. Co-immunoprecipitation studies revealed an interaction of Hsp70 with NF-κB and IκBα, but not with IkB kinase, IKKγ, suggesting that Hsp70 binds to the NF-κB:IκB complex preventing IκB phosphorylation by IKK. The findings of the present work establish an anti-inflammatory role for Hsp70 in the context of brain ischemia as a novel mechanism of protection.

scholarly journals Postischemic Neuroprotection Associated With Anti-Inflammatory Effects by Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles in Aged Mice

Stroke ◽  
2021 ◽  
Author(s):  
Chen Wang ◽  
Verena Börger ◽  
Ayan Mohamud Yusuf ◽  
Tobias Tertel ◽  
Oumaima Stambouli ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Infarct Volume ◽  
Artery Occlusion ◽  
Polymorphonuclear Neutrophils ◽  
Neurological Deficits ◽  
Polymorphonuclear Neutrophil ◽  
Activated T Cells ◽  
Aged Mice ◽  
Blood Leukocyte ◽  
Cerebral Artery Occlusion

Background and Purpose: Small extracellular vesicles (sEVs) obtained from mesenchymal stromal cells (MSCs) were shown to induce ischemic neuroprotection in mice by modulating the brain infiltration of leukocytes and, specifically polymorphonuclear neutrophils. So far, effects of MSC-sEVs were only studied in young ischemic rodents. We herein examined the effects of MSC-sEVs in aged mice. Methods: Male and female C57Bl6/j mice (8–10 weeks or 15–24 months) were exposed to transient intraluminal middle cerebral artery occlusion. Vehicle or sEVs (equivalent of 2×10 6 MSCs) were intravenously administered. Neurological deficits, ischemic injury, blood-brain barrier integrity, brain leukocyte infiltration, and blood leukocyte responses were evaluated over up to 7 days. Results: MSC-sEV delivery reduced neurological deficits, infarct volume, brain edema, and neuronal injury in young and aged mice of both sexes, when delivered immediately postreperfusion or with 6 hours delay. MSC-sEVs decreased leukocyte and specifically polymorphonuclear neutrophil, monocyte, and macrophage infiltrates in ischemic brains of aged mice. In peripheral blood, the number of monocytes and activated T cells was significantly reduced by MSC-sEVs. Conclusions: MSC-sEVs induce postischemic neuroprotection and anti-inflammation in aged mice.

scholarly journals CD28 Superagonist-Mediated Boost of Regulatory T Cells Increases Thrombo-Inflammation and Ischemic Neurodegeneration during the Acute Phase of Experimental Stroke

2014 ◽  
Vol 35 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Michael K Schuhmann ◽  
Peter Kraft ◽  
Guido Stoll ◽  
Kristina Lorenz ◽  
Sven G Meuth ◽  
...  
Keyword(s):  
T Cells ◽  
Ischemic Stroke ◽  
Regulatory T Cells ◽  
Thrombus Formation ◽  
Inflammatory Lesion ◽  
Artery Occlusion ◽  
Acute Stage ◽  
Experimental Stroke ◽  
Cerebral Artery Occlusion

While the detrimental role of non-regulatory T cells in ischemic stroke is meanwhile unequivocally recognized, there are controversies about the properties of regulatory T cells (Treg). The aim of this study was to elucidate the role of Treg by applying superagonistic anti-CD28 antibody expansion of Treg. Stroke outcome, thrombus formation, and brain-infiltrating cells were determined on day 1 after transient middle cerebral artery occlusion. Antibody-mediated expansion of Treg enhanced stroke size and worsened functional outcome. Mechanistically, Treg increased thrombus formation in the cerebral microvasculature. These findings confirm that Treg promote thrombo-inflammatory lesion growth during the acute stage of ischemic stroke.

scholarly journals Lempel-Ziv complexity of the EEG predicts long-term functional recovery after stroke in rats

2018 ◽  
Author(s):  
Susan Leemburg ◽  
Claudio L. Bassetti
Keyword(s):  
Motor Function ◽  
Functional Recovery ◽  
Brain Function ◽  
Complexity Analysis ◽  
Recovery Period ◽  
Artery Occlusion ◽  
Multiscale Entropy ◽  
Experimental Stroke ◽  
Reaching Task ◽  
Post Stroke

AbstractNon-linear complexity of the EEG signal can be used to detect abnormal brain function relating to behavioral deficits. Here, we compare the effects of experimental stroke on EEG complexity using Lempel-Ziv complexity analysis (LZC) and multiscale entropy analysis (SampEn).EEG was recorded in bilateral motor cortex at baseline and during a 30-day recovery period after distal middle cerebral artery occlusion in rats. Motor function was assessed using a single pellet reaching task. Stroke caused an acute drop in both LZC and SampEn in the ipsilesional hemisphere in wakefulness, NREM and REM sleep, as well as reduced pellet reaching success. SampEn reductions persisted for at least 10 days post-stroke, whereas LZC had returned to baseline levels by day 4. EEG complexity in the contralesional hemisphere and in sham-operated animals were unaffected.If EEG complexity reflects post-stroke brain function, post-stroke asymmetry could be used to predict behavioral recovery. In rats, acute LZC asymmetry was significantly correlated with the amount of motor function recovery by post-stroke day 31, but SampEn asymmetry was not. EEG LZC may thus be a useful tool for predicting functional recovery after stroke. MSE could be effective in identifying cortical dysfunction, but does not reflect behavioral outcomes.

scholarly journals Intra-Arterial Stem Cell Transplantation in Experimental Stroke in Rats: Real-Time MR Visualization of Transplanted Cells Starting With Their First Pass Through the Brain With Regard to the Therapeutic Action

2021 ◽  
Vol 15 ◽  
Author(s):  
Daria D. Namestnikova ◽  
Ilya L. Gubskiy ◽  
Veronica A. Revkova ◽  
Kirill K. Sukhinich ◽  
Pavel A. Melnikov ◽  
...  
Keyword(s):  
Real Time ◽  
Close Contact ◽  
Infarct Volume ◽  
Neurological Deficits ◽  
Experimental Stroke ◽  
Therapeutic Effects ◽  
Stroke Treatment ◽  
First Pass ◽  
Pass Through ◽  
The Brain

Cell therapy is an emerging approach to stroke treatment with a potential to limit brain damage and enhance its restoration after the acute phase of the disease. In this study we tested directly reprogrammed neural precursor cells (drNPC) derived from adult human bone marrow cells in the rat middle cerebral artery occlusion (MCAO) model of acute ischemic stroke using human placenta mesenchymal stem cells (pMSC) as a positive control with previously confirmed efficacy. Cells were infused into the ipsilateral (right) internal carotid artery of male Wistar rats 24 h after MCAO. The main goal of this work was to evaluate real-time distribution and subsequent homing of transplanted cells in the brain. This was achieved by performing intra-arterial infusion directly inside the MRI scanner and allowed transplanted cells tracing starting from their first pass through the brain vessels. Immediately after transplantation, cells were observed in the periphery of the infarct zone and in the brain stem, 15 min later small numbers of cells could be discovered deep in the infarct core and in the contralateral hemisphere, where drNPC were seen earlier and in greater numbers than pMSC. Transplanted cells in both groups could no longer be detected in the rat brain 48–72 h after infusion. Histological and histochemical analysis demonstrated that both the drNPC and pMSC were localized inside blood vessels in close contact with the vascular wall. No passage of labeled cells through the blood brain barrier was observed. Additionally, the therapeutic effects of drNPC and pMSC were compared. Both drNPC and pMSC induced substantial attenuation of neurological deficits evaluated at the 7th and 14th day after transplantation using the modified neurological severity score (mNSS). Some of the effects of drNPC and pMSC, such as the influence on the infarct volume and the survival rate of animals, differed. The results suggest a paracrine mechanism of the positive therapeutic effects of IA drNPC and pMSC infusion, potentially enhanced by the cell-cell interactions. Our data also indicate that the long-term homing of transplanted cells in the brain is not necessary for the brain’s functional recovery.

Abstract 12: S-Nitrosylation Invokes Functional Recovery from Experimental Stroke through the Hypoxia-inducible Factor-1 alpha/Vascular Endothelial Growth Factor Pathway

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Mushfiquddin Khan ◽  
Tajinder S Dhammu ◽  
Fumiyo Matsuda ◽  
Inderjit Singh ◽  
Avtar K Singh
Keyword(s):  
Functional Recovery ◽  
Infarct Volume ◽  
Ischemia Reperfusion ◽  
Hypoxia Inducible Factor ◽  
Artery Occlusion ◽  
Tube Formation ◽  
Male Rats ◽  
Experimental Stroke ◽  
Capillary Endothelial Cells ◽  
Stimulation Of

Background: In stroke patients, the stimulation of neurorepair mechanisms is necessary to reduce morbidity and disability. Our studies on brain and spinal cord trauma show that an exogenous treatment with the S-nitrosylating agent S-nitrosoglutathione (GSNO) stimulates neurorepair and aids functional recovery. Using a rat model of cerebral ischemia reperfusion (IR), we tested the hypothesis that GSNO invokes the neurorepair process and improves neurobehavioral functions through the angiogenic HIF-1α/VEGF pathway. Methods: Stroke was induced by middle cerebral artery occlusion for 60 min followed by reperfusion in adult male rats. The injured animals were treated with vehicle (IR group, n=7), GSNO (0.25 mg/kg, GSNO group, n=7), and GSNO plus the HIF-1α inhibitor 2-mthoxyestradiol (0.25 mg/kg GSNO+5.0 mg/kg ME, GSNO+ME group, n=7). The groups were studied for 14 days to determine neurorepair mechanisms and functional recovery. Brain capillary endothelial cells were used to show that GSNO promotes angiogenesis and that GSNO-mediated induction of VEGF and the stimulation of angiogenesis are dependent on HIF-1α activity. Results: GSNO treatment of IR enhanced the expression of HIF-1α, VEGF, and PECAM-1. This GSNO treatment also led to increased expression of neurorepair mediators including BDNF. Increased expression of VEGF/BDNF and the degree of tube formation (angiogenesis) by GSNO were reduced in an endothelial cell culture model after the inhibition of HIF-1α by ME. ME treatment of the GSNO group also blocked not only GSNO’s effect of reduced infarct volume (p<0.05) and enhanced expression of PECAM-1but also its improvement of motor and neurological functions (p<0.001). Conclusions: GSNO shows therapeutic promise for stroke by stimulating the process of neurorepair and aiding functional recovery through the HIF-1α/VEGF/PECAM-1 dependent pathway.

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