Brain Reperfusion Research Articles

Mechanical Reperfusion Following Prolonged Global Cerebral Ischemia Attenuates Brain Injury

Previous experiments demonstrated improved outcome following prolonged cerebral ischemia given controlled brain reperfusion using extracorporeal circulation. The current study further investigates this. Young adult pigs were exposed to 30 min of global normothermic cerebral ischemia, achieved through intrathoracic clamping of cerebral arteries, followed by 20 min of isolated mechanical brain reperfusion. Leukocyte-filtered blood was delivered by a roller-pump at fixed pressure and flow. One experimental group additionally had a custom-made buffer solution delivered at 1:8 ratio with the blood. Hemodynamics including intracranial pressure were monitored. Blood gases were from peripheral arteries and the sagittal sinus, and intraparenchymal brain microdialysis was performed. The brains were examined by a neuropathologist. The group with the added buffer showed lower intracranial pressure as well as decreased intraparenchymal glycerol and less signs of excitotoxicity and ischemia, although histology revealed similar degrees of injury. A customized mechanical reperfusion improves multiple parameters after prolonged normothermic global cerebral ischemia.Graphical The current study investigates if it possible to improve neurological outcomes following prolonged global brain ischemia. The results indicate that a customized mechanical reperfusion protocol can attenuate neurological injury.

Danegaptide Enhances Astrocyte Gap Junctional Coupling and Reduces Ischemic Reperfusion Brain Injury in Mice.

Ischemic stroke is a complex and devastating event characterized by cell death resulting from a transient or permanent arterial occlusion. Astrocytic connexin43 (Cx43) gap junction (GJ) proteins have been reported to impact neuronal survival in ischemic conditions. Consequently, Cx43 could be a potential target for therapeutic approaches to stroke. We examined the effect of danegaptide (ZP1609), an antiarrhythmic dipeptide that specifically enhances GJ conductance, in two different rodent stroke models. In this study, danegaptide increased astrocytic Cx43 coupling with no significant effects on Cx43 hemichannel activity, in vitro. Using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) the presence of danegaptide within brain tissue sections were detected one hour after reperfusion indicating successful transport of the dipeptide across the blood brain barrier. Furthermore, administration of danegaptide in a novel mouse brain ischemia/reperfusion model showed significant decrease in infarct volume. Taken together, this study provides evidence for the therapeutic potential of danegaptide in ischemia/reperfusion stroke.

Protection against acute cerebral ischemia/reperfusion injury by QiShenYiQi via neuroinflammatory network mobilization

Cerebral ischemia/reperfusion injury (CI/RI) is a common feature of ischemic stroke, involving a period of impaired blood supply to the brain, followed by the restoration of cerebral perfusion through medical intervention. Although ischemia and reperfusion brain damage is a complex pathological process with an unclear physiological mechanism, more attention is currently focused on the neuroinflammatory response of an ischemia/reperfusion origin, and anti-inflammatory appears to be a potential therapeutic strategy following ischemic stroke. QiShenYiQi (QSYQ), a component-based Chinese medicine with Qi-tonifying and blood-activating property, has pharmacological actions of anti-inflammatory, antioxidant, mitochondrial protectant, anti-apoptosis, and antiplatelet aggregation. We have previously reported that the cardioprotective effect of QSYQ against ischemia/reperfusion injury is via improvement of mitochondrial functional integrity. In this research work, we aimed to investigate the possible mechanism involved in the neuroprotection of QSYQ in mice model of cerebral ischemia/reperfusion injury based on the inflammatory pathway. The cerebral protection was evaluated in the stroke mice after 24 h reperfusion by assessing the neurological deficit, cerebral infarction, brain edema, BBB functionality, and via histopathological assessment. TCM-based network pharmacology method was performed to establish and analyze compound-target-disease & function-pathway network so as to find the possible mechanism linking to the role of QSYQ in CI/RI. In addition, RT-qPCR was used to verify the accuracy of predicted signaling gene expression. As a result, improvement of neurological outcome, reduction of infarct volume and brain edema, a decrease in BBB disruption, and amelioration of histopathological alteration were observed in mice pretreated with QSYQ after experimental stroke surgery. Network pharmacology analysis revealed neuroinflammatory response was associated with the action of QSYQ in CI/RI. RT-qPCR data showed that the mice pretreated with QSYQ could significantly decrease IFNG-γ, IL-6, TNF-α, NF-κB p65, and TLR-4 mRNA levels and increase TGF-β1 mRNA level in the brain compared to the untreated mice after CI/RI (p < 0.05). In conclusion, our study indicated the cerebral protective effect of pretreatment with QSYQ against CI/RI, which may be partly related to its potential to the reduction of neuroinflammatory response in a stroke subject.

Abstract WP411: Asymptomatic Hemorrhage Predicts Delayed Symptomatic Hemorrhage After Alteplase in Acute Ischemic Stroke

Background: Predictors of alteplase associated symptomatic intracranial hemorrhage (sICH) have been identified but there are very limited data on predictors of delayed sICH (&gt; 24 hours from infusion). We hypothesize that asymptomatic hemorrhage on 24 hour brain imaging predicts delayed sICH and that delaying antithrombotic treatment in these patients reduces this risk. Methods: This is a retrospective analysis of a prospective quality improvement database of a comprehensive stroke center. We included all patients with a discharge diagnosis of ischemic stroke who received alteplase. Patients with sICH occurring within 24 hours from alteplase and those whose code status was changed to comfort measures only were excluded. Delayed sICH was defined as any hemorrhage causing neurological deterioration. We compared baseline characteristics, asymptomatic hemorrhage on 24 hour brain imaging, and median time to initiating antithrombotic therapy between patients with and without delayed sICH. Results: Among 606 patients who met our inclusion criteria; mean age was 70 years and 52% were men; 23.8% had asymptomatic hemorrhage on 24 hour brain imaging (CT or MRI) and 12 patients (2%) had delayed sICH. Aspirin was the most common initial antithrombotic (91.2%) followed by plavix (2.6%), and others (3.8%). After adjusting for confounders, asymptomatic hemorrhage on 24 hour brain imaging was associated with increased odds of delayed sICH (OR 5.5, 95% CI 1.52 - 19.87, p = 0.009) but the median time (days) to starting antithrombotic therapy did not differ between those with asymptomatic hemorrhage who developed delayed sICH vs. those who did not [2 (3) vs. 3 (5), p = 0.447). Conclusion: Delayed sICH in patients receiving alteplase is uncommon and asymptomatic hemorrhage is a strong predictor. Delaying initiation of antithrombotic treatment in patients with asymptomatic hemorrhage on 24 hour imaging was not associated with reduced delayed sICH risk. It is possible that other factors such as reperfusion and blood brain barrier disruption are more important determinants of delayed sICH risk as opposed to timing of antithrombotic therapy initiation.

Maintaining the permanence principle for death during in situ normothermic regional perfusion for donation after circulatory death organ recovery: A United Kingdom and Canadian proposal.

There is international variability in the determination of death. Death in donation after circulatory death (DCD) can be defined by the permanent cessation of brain circulation. Post‐mortem interventions that restore brain perfusion should be prohibited as they invalidate the diagnosis of death. Retrieval teams should develop protocols that ensure the continued absence of brain perfusion during DCD organ recovery. In situ normothermic regional perfusion (NRP) or restarting the heart in the donor's body may interrupt the permanent cessation of brain perfusion because, theoretically, collateral circulations may restore it. We propose refinements to current protocols to monitor and exclude brain reperfusion during in situ NRP. In abdominal NRP, complete occlusion of the descending aorta prevents brain perfusion in most cases. Inserting a cannula in the ascending aorta identifies inadequate occlusion of the descending aorta or any collateral flow and diverts flow away from the brain. In thoracoabdominal NRP opening the aortic arch vessels to atmosphere allows collateral flow to be diverted away from the brain, maintaining the permanence standard for death and respecting the dead donor rule. We propose that these hypotheses are correct when using techniques that simultaneously occlude the descending aorta and open the aortic arch vessels to atmosphere.

Effect of Adenosine Injection Following Cerebral Reperfusion Ischemia on A1AR Gene Expression and Apoptosis in Brain Hippocampal Tissue of Male Wistar Rats

Background: Apoptosis is a programmed cell death that occurs due to various factors such as reperfusion ischemia. As a purinergic receptor, A1AR acts as an oxidative stress sensor and an antioxidant during reperfusion ischemia. Objectives: The purpose of the present study was to investigate the effect of adenosine injection following cerebral reperfusion ischemia on A1AR gene expression and apoptosis in the brain hippocampal tissue of male Wistar rats. Methods: This experimental study was conducted at Shahid Mirghani Research Institute in Gorgan, Iran, from January 21, 2019, to March 18, 2019. The sample size was determined according to previous studies and a pilot study. Thus, 30 male Wistar rats were divided into three groups by simple random sampling (using a random-number table): Control group (n = 10), Reperfusion ischemia group (n = 10), and Reperfusion ischemia + adenosine group (n = 10). Ischemia was induced in animals by closing the carotid artery for 45 min. Adenosine was injected 24 h after ischemia. We measured A1AR gene expression, SOD protein expression, and apoptosis by real-time PCR, immunohistochemistry, and the TUNEL method, respectively. Results: The results showed that cerebral reperfusion ischemia significantly increased A1AR gene expression (596%) and apoptosis (378%) and decreased SOD protein expression (72%) compared to the control group (P < 0.001). On the other hand, adenosine significantly reduced A1AR gene expression (46%) and apoptosis (69%) and increased SOD protein expression (94%) compared to the ischemic group (P < 0.001). Conclusions: Ischemic brain reperfusion causes oxidative stress. Also, adenosine injection seems to be effective in reducing oxidative stress and apoptosis induced by cerebral reperfusion ischemia.

Additive Protective Effect of Insulin and Alpha-Tocopherol on Brain Cortical Neurons in Oxidative Stress and in the Conditions of Two-Vessel Brain Ischemia and Reperfusion

Additive Protective Effect of Insulin and Alpha-Tocopherol on Brain Cortical Neurons in Oxidative Stress and in the Conditions of Two-Vessel Brain Ischemia and Reperfusion

Effect of 3-Aminobenzamide on the Ultrastructure of Astrocytes and Microvessels After Focal Cerebral Ischemia in Rats.

The disruption of blood–brain barrier (BBB) is a critical event in the formation of brain edema during early phases of ischemic brain injury. Poly(ADP-ribose) polymerase (PARP) activation, which contributes to BBB damage, has been reported in ischemia–reperfusion and traumatic brain injury. Here, we investigated the effect of 3-aminobenzamide (3-AB), a PARP-1 inhibitor, on the ultrastructure of BBB. Male Sprague Dawley rats were suffered from 90 minutes of middle cerebral artery occlusion, followed by 4.5 hours or 22.5 hours of reperfusion (R). The vehicle or 3-AB (10 mg/kg) was administered intraperitoneally (ip) 60 minutes after lacking of blood. Tissue Evans Blue (EB) levels, ultrastructures of astrocytes and microvessels, and areas of perivascular edema were examined in penumbra and core, at I 1.5 hours /R 4.5 hours and I 1.5 hours /R 22.5 hours, respectively. The severity of ultrastructural changes was graded with a scoring system in each group. We showed that 3-AB treatment significantly decreased tissue EB levels and ultrastructural scores, attenuated damages in astrocytes and microvessels, and reduced areas of perivascular edema. In conclusion, PARP inhibition may provide a novel therapeutic approach to ischemic brain injury.

Desflurane-based balanced anesthesia in reconstructive carotid artery surgery

The aim of the research was to examine the influence of isoflurane inhalation on the circulatory dynamics, encephalic bloodstream and oxygen balance of the patients’ brain during the carotid endarterectomy. 26 patients were examined. There were detected the parameters of central and systemic circulatory dynamics, the speed of the bloodstream in the middle encephalic artery in M, sector, the results of transcranial cerebral oxymetry. The first stages of the operation, the stage of temporary breakoff of the blood circulation in damaged artery territory were accompanied with moderate lowering of indicators of circulatory dynamics. In the process of reinitiation of the bloodstream the reperfusion of brain declared itself moderately. Isoflurane anesthesia to 1 MAK (minimum alveolar concentration) in combination with phentanyl allows to maintain appropriate pain management, stable circulatory dynamics and well-timed awakening of patients during carotid endarterectomy.

Critical Shifts in Cerebral White Matter Lipid Profiles After Ischemic-Reperfusion Brain Injury in Fetal Sheep as Demonstrated by the Positive Ion Mode MALDI-Mass Spectrometry.

Ischemic–reperfusion (I/R) injury to cerebral white matter during the perinatal period leads to long-term cognitive and motor disabilities in children. Immature white matter oligodendrocytes are especially vulnerable to metabolic insults such as those caused by hypoxic, ischemic, and reperfusion injury. Consequences include an impaired capacity of oligodendrocytes to generate and maintain mature lipid-rich myelin needed for efficient neuronal conductivity. Further research is needed to increase an understanding of the early, possibly reversible myelin-associated pathologies that accompany I/R white matter injury. This experiment characterized I/R time-dependent alterations in cerebral white matter lipid profiles in an established fetal sheep model. Fetal sheep (127 days gestation) were subjected to 30 min of bilateral carotid artery occlusion followed by 4 h (n = 5), 24 h (n = 7), 48 h (n = 3), or 72 h (n = 5) of reperfusion, or sham treatment (n = 5). Supraventricular cerebral white matter lipids were analyzed using the positive ionization mode matrix-assisted laser desorption/ionization mass spectrometry. Striking I/R-associated shifts in phospholipid (PL) and sphingolipid expression with a prominent upregulation of cardiolipin, phosphatidylcholine, phosphatidylinositol monomannoside, sphingomyelin, sulfatide, and ambiguous or unidentified lipids were observed to occur mainly at I/R-48 and normalized or suppressed responses at I/R-72. In fetal sheep, cerebral I/R caused major shifts in white matter myelin lipid composition favoring the upregulated expression of diverse PLs and sphingolipids which are needed to support neuronal membrane, synaptic, metabolic, and cell signaling functions.

IL-37: Novel neuroprotective effects after brain ischemia and reperfusion

Interleukin-1 (IL-1) is a central mediator of innate immunity and inflammation. IL-37 (IL-37), a newly described member of the IL-1 family, functions as a fundamental inhibitor of innate inflammation and immunity. The purpose of the present study was to determine the effects of interleukin-37 on neuron cells and on brain inflammation induced by brain ischemia/reperfusion (I/R). A transgenic mouse strain was generated to express human IL-37 (hIL-37Tg) and WT mice were subjected to (60 min) brain ischemia and followed by reperfusion (24 h), by using a mice model of transient focal cerebral ischemia induced by advancing a nylon mono-filament to occlude the middle cerebral artery (MCA). Infarct size was determined by triphenyltetrazolium chloride staining. The morphology of neurons in brain sections were examined by Nissl staining and cytokines/chemokines measured by ELIZA. IL-37Tg significantly reduced infarct size by 65.4% (P&lt;0.05) compared with WT after I/R. Reduced inflammation was associated with decreased leukocyte recruitment, and reduced release of IL-1β and TNFα, macrophage inflammatory protein-2 (MIP-2), MCP-1 and keratinocyte chemokine (KC) compared with WT (P&lt;0.05), whereas IL-10 was increased eight fold (P&lt;0.05). IL-37 significantly reduced cell death and increased Bcl-2 expression in neurons. Thus, IL-37 emerges as a key modulator of brain inflammation and has important translational implications for both the prevention and treatment of patients suffering from brain ischemia.

Prolonged perfusion of rat brain with a high oxygen tension solution, without oxygen carriers and with an external normal barometric pressure

BackgroundIsolated brain of experimental animals is a useful model to study transport of substances, including drugs, across the blood-brain barrier, mechanisms of convulsive activity, ischemic and reperfusion brain injury. Normal functioning of neurons, especially cortical, in the central nervous system requires adequate supply of oxygen. Therefore oxygen carriers or fluorocarbon substances with high oxygen capacity are often used in animal brain perfusion experiments. New methodIn the present study of the in situ rat brain perfusion oxygen carriers were not used. The optimum oxygen capacity of the perfusion media (adequate to the arterio-venous difference) was achieved by a high oxygen tension (2400−2600 mm Hg) in the solution under normal barometric pressure. Perfusate was depressurized and delivered at normal rat systemic hydrostatic pressure to the brain via a cannula inserted transcardially into the ascending aorta, with both subclavian arteries ligated. Perfusate was delivered using normal hydrostatic pressure. ResultsIn these experimental conditions of the brain perfusion the pattern of electrocorticogram has been stable in the course of 5 h and more. The release of lactic acid in the perfusion solution was 3 times less than in perfusion under partial oxygen tension of 900 mm Hg; excessive activation of the lipid peroxidation process in the brain tissue was not observed. ConclusionThe presented new model of the isolated brain perfusion may be used in experiments with other isolated organs and in studies of toxic effects of oxygen.

Leukocytes, Collateral Circulation, and Reperfusion in Ischemic Stroke Patients Treated With Mechanical Thrombectomy

Background and Purpose- Peripheral immune cells are activated after stroke and may in turn influence the fate of ischemic brain tissue, thus exerting a dual role in ischemic stroke. We evaluated the contribution of neutrophil and lymphocyte counts to hemorrhagic complications and functional outcome in stroke patients treated with mechanical thrombectomy (MT) with varying degrees of collateral circulation and reperfusion. Methods- We retrospectively analyzed 433 consecutive ischemic stroke patients treated with MT. Neutrophil and lymphocyte counts and the neutrophil-to-lymphocyte ratio (NLR) were collected before MT and 1 day after symptom onset. Outcome measures included categories of hemorrhagic transformation, symptomatic intracerebral hemorrhage, 3-month functional dependence (modified Rankin Scale, 3-6), and mortality. Patients were categorized according to their baseline collateral status and the degree of reperfusion after MT. Results- Neutrophil counts and NLR increased, whereas lymphocyte counts decreased after MT (P<0.001), and changes in neutrophils and NLR at day 1 were significantly greater in patients with poor reperfusion. Neutrophil counts and NLR were significantly higher already at admission in patients with poor 3-month outcome. In adjusted analysis, the impact of neutrophilia on poor functional outcome was more substantial in patients with good collaterals achieving successful reperfusion (aOR, 3.09 per quartile; 95% CI, 1.95-4.90), whereas admission lymphopenia (aOR, 4.08 per decreasing quartile; 95% CI, 1.56-10.64) and higher NLR (aOR, 3.76 per quartile; 95% CI, 1.44-9.79) predicted subsequent symptomatic intracerebral hemorrhage in patients with poor collaterals and successful reperfusion. Conclusions- In patients treated with MT, neutrophil and lymphocyte counts are dynamic parameters associated with hemorrhagic complications and long-term outcome. The extent of collateral circulation and the success of brain reperfusion influence the strength of these associations and highlight the dual role of leukocytes in acute stroke.

Endothelial Targets in Stroke: Translating Animal Models to Human.

Cerebral ischemia (stroke) induces injury to the cerebral endothelium that may contribute to parenchymal injury and worsen outcome. This review focuses on current preclinical studies examining how to prevent ischemia-induced endothelial dysfunction. It particularly focuses on targets at the endothelium itself. Those include endothelial tight junctions, transcytosis, endothelial cell death, and adhesion molecule expression. It also examines how such studies are being translated to the clinic, especially as adjunct therapies for preventing intracerebral hemorrhage during reperfusion of the ischemic brain. Identification of endothelial targets may prove valuable in a search for combination therapies that would specifically protect different cell types in ischemia.

Delayed Effects of Acute Reperfusion on Vascular Remodeling and Late-Phase Functional Recovery After Stroke.

Tissue perfusion is a necessary condition for vessel survival that can be compromised under ischemic conditions. Following stroke, delayed effects of early brain reperfusion on the vascular substrate necessary for remodeling, perfusion and maintenance of proper peri-lesional hemodynamics are unknown. Such aspects of ischemic injury progression may be critical for neurological recovery in stroke patients. This study aims to describe the impact of early, non-thrombolytic reperfusion on the vascular brain component and its potential contribution to tissue remodeling and long-term functional recovery beyond the acute phase after stroke in 3-month-old male C57bl/6 mice. Permanent (pMCAO) and transient (60 min, tMCAO) brain ischemia mouse models were used for characterizing the effect of early, non-thrombolytic reperfusion on the brain vasculature. Analysis of different vascular parameters (vessel density, proliferation, degeneration and perfusion) revealed that, while early middle cerebral artery recanalization was not sufficient to prevent sub-acute vascular degeneration within the ischemic brain regions, brain reperfusion promoted a secondary wave of vascular remodeling in the peri-lesional regions, which led to improved perfusion of the ischemic boundaries and late-phase neurological recovery. This study concluded that acute, non-thrombolytic artery recanalization following stroke favors late-phase vascular remodeling and improves peri-lesional perfusion, contributing to secondary functional recovery.

Neuroprotective Effects and Hepatorenal Toxicity of Angong Niuhuang Wan Against Ischemia-Reperfusion Brain Injury in Rats.

Angong Niuhuang Wan (AGNHW) is a classic prescription in traditional Chinese medicine (TCM) used for stroke treatment, but its efficacies remain to be confirmed. With its arsenic- and mercury-containing materials, the application of AGNHW raises great safety concerns. Herein, we aim to explore the neuropharmacological effects against cerebral ischemia–reperfusion injury and evaluate the toxicological effects of AGNHW for better use. Male SD rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) and following 22 h of reperfusion. AGNHW (257 mg/kg, 1× AGNHW) were orally administered for pharmacological effects and 257, 514, and 1,028 mg/kg (equivalent to 1×, 2×, 4× AGNHW) were used for the toxicological study. The results revealed that AGNHW treatment reduced the infarct size and protected the blood–brain barrier (BBB) integrity in the MCAO rat ischemic stroke model. AGNHW treatment up-regulated bcl-2 expression and down-regulated the expressions of Bax, p47phox, inducible nitric oxide synthase (iNOS), and 3-nitrotyrosine (3-NT), and inhibited the expressions and activities of matrix metalloproteinase-2 (MMP-2), MMP-9, and reserved tight junction protein zonula occludens-1 (ZO-1) and claudin-5 in the ischemic brains. These results indicated that the neuroprotective mechanisms of AGNHW could be associated with its antioxidant properties by inhibiting oxidative/nitrative stress-mediated MMP activation and protecting tight junction proteins in the ischemic brains. Administration of 1× AGNHW for 7 days would not induce the accumulation of mercury in blood, liver, and kidney at day 14. Administration of 2× AGNHW and 4× AGNHW for 7 days increased the level of mercury in the kidney. For arsenic level, administration of 1× AGNHW for 7 days would increase the level of arsenic in the liver and blood without increase of arsenic in the kidney at day 14. Administration of 2× AGNHW and 4× AGNHW for 7 days would further increase the level of arsenic in the liver and blood. There is no influence on body weight, organ index, histological structures, and renal and liver functions. These results suggest that short-term treatment of AGNHW within 1 week should be safe and has neuroprotective effects against cerebral ischemia–reperfusion injury.

The dawn era in the management of acute ischemic stroke and its health policy implications. Should interventional cardiologists be involved?

Similarly to what happened for myocardial infarction treatment during the two previous decades, ischemic stroke therapy has radically changed in recent years after the encouraging clinical results on the use of mechanical revascularization systems. The ever-increasing use of thrombectomy, which is now the first-choice approach for achieving rapid reperfusion of the ischemic brain, inaugurates a new era in the treatment of ischemic stroke, with important social and healthcare implications and the need for effective integrated stroke networks on a regional basis.Given the high annual rates of stroke and that approximately 35% of strokes are caused by the thrombotic occlusion of a large cerebral vessel, with a treatment window reaching up to 24 h after onset in selected cases, the resources of interventional neuroradiology are not enough to meet treatment needs in terms of performing centers and number of operators. The possibility of using centers already active for the treatment of acute myocardial infarction has therefore been taken into consideration. This article presents objective data to support the validity of this strategy and discusses how to create treatment networks using the interventional skills of cardiologists with the implementation of multidisciplinary functional structures.

Abstract TP139: MicroRNAs Expression Patterns of Hemorrhagic Transformation After Mechanical Reperfusion for Acute Ischemic Stroke in Rat

Background: Severe hemorrhagic transformation (HT) after mechanical thrombectomy and intravenous thrombolysis predicts poor clinical outcome in acute ischemic stroke. The specific roles of microRNAs in the pathogenesis of HT, however, are still unclear. Thus, the aim of this study is to investigate miRNA expression profiles in the rat ischemic brain with HT after mechanical reperfusion. Methods: A model of reperfusion-induced HT was established in rats with hyperglycemic challenge and 5h middle cerebral artery occlusion (MCAO) followed by 19h reperfusion. Infarct volume, brain water content, HT, neurological score, and blood-brain barrier damage were determined at 24h after cerebral ischemia. The miRNA expression profiling of rat brain samples in the MCAO group and those in the sham-operated group was performed using the miRCURYLNA Array. The differentially expressed miRNAs were further validated by qRT-PCR. Then, after predicting their target genes from top-ranked miRNAs, the KEGG and GO analyses were further used to predict the associated significant cell signaling pathways and functions. Results: Reperfusion with 5h of MCAO induced HT in all hyperglycemic rats, and most of them were the parenchymal hematoma. The results from the miRNA array revealed that 57 miRNAs were significantly altered 24h after reperfusion in the ischemic brain with HT. The expressions of these 57 miRNAs were further verified using qRT-PCR, and 33 top-ranked miRNAs were confirmed. Among them, 30 miRNAs were significantly downregulated and 3 were significantly upregulated in rats with HT. The top-listed downregulated miRNAs included miR-383-5p, miR-335, miR-376a-5p, miR-212-5p, miR-219a, miR-126a-5p. Three miRNAs were significantly upregulated, including miR-125b, miR-195, miR-214. The most enriched pathways are associated with the Hippo signaling pathway which regulates cell survival and death. Twenty significantly regulated miRNAs involve into the Hippo signaling pathway, including miR-383-5p. Conclusions: Alteration of the miRNAs in the ischemic brain with HT may serve as biomarkers for HT after mechanical reperfusion in acute ischemic stroke. The role of reperfusion-inducible miR-383-5p and Hippo signaling pathway in the HT requires further investigation.

Abstract WP11: Semi-automated Quantitative Assessment of Reperfusion in Acute Ischemic Stroke Patients

Introduction: Accurate assessment of brain reperfusion during endovascular treatment helps determining whether adjuvant intervention is necessary. The gold standard for reperfusion scales are the modified and extended Treatment in Cerebral Ischemia (mTICI and eTICI) scale. However, these scales are coarse and highly dependent on the observer, which may result in imprecise rating of reperfusion status. In this study, we developed a semi-automated quantitative reperfusion measure (qTICI) that was based on eTICI methodology using deep learning. Methods: Digital subtraction angiography (DSA) images of 67 acute ischemic stroke patients with proximal occlusions were collected from the MRCLEAN registry, including only patients who were eTICI graded by an independent core lab and had follow-up 90 days-modified Rankin Scale (mRS) scores. Both DSA projections, anteroposterior and lateral, were used. We trained a patch-based multi-path convolutional neural network to segment the perfusion area. The ground truths of perfusion segmentation were constructed using heuristic, intensity thresholding after vessel removal, which were inspected for their accuracy by a neuroradiologist. The target downstream territory was manually segmented based on the treated occlusion location by two neurointerventionalists. qTICI was formulated as a ratio between the area of perfusion and target downstream territory. We compared performance between qTICI and eTICI in relation with functional outcome, dichotomized as favorable (mRS 0-2) and unfavorable outcome (mRS 3-6). Results: Our study showed that the multi-path convolutional neural network was able to reproduce the ground truth perfusion segmentation with an average Dice score of 0.91. qTICI correlated significantly with eTICI (p&lt;0.001) and the ordinal 90-days mRS (p&lt;0.05). qTICI had comparable discriminative power to distinguish between favorable and unfavorable functional outcome (AUC = 0.80) with eTICI (AUC = 0.81). Conclusions: qTICI provided a quantitative and semi-automated perfusion assessment with strong association with functional outcome.

Gasdermin D serves as a key executioner of pyroptosis in experimental cerebral ischemia and reperfusion model both in vivo and in vitro.

Even though ischemic stroke is among the leading causes of death worldwide, the pathogenic mechanisms underlying ischemia reperfusion (I/R) brain injury remain unclear. Gasdermin D (GSDMD), as an important factor of pyroptotic death execution downstream of caspase-11 (noncanonical inflammasome) and caspase-1 (canonical inflammasome), may be implicated in I/R injury. The current study aimed to investigate the role and possible underlying mechanisms of GSDMD in pyroptosis during I/R injury. Results indicated that the nucleotide-binding oligomerization domain-like receptors (NLR family) pyrin domain containing 3 (NLRP3) inflammasomes were assembled and activated after middle cerebral artery occlusion/reperfusion (MCAO/R), leading to increased levels of IL-1β and IL-18. Additionally, GSDMD levels were elevated, and its N-terminal fragment (GSDMD-N) was cleaved to induce pyroptosis after MCAO/R, which was partly dependent on caspase-1 activation and its Asp280 amino acid site. Furthermore, it was found that GSDMD-N could bind to membrane lipids and exhibit membrane-disrupting cytotoxicity, depending on its Glu15 and Leu156 amino acid sites. Nevertheless, the C-terminal fragment of gasdermin (GSDMD-C) exhibited an auto-inhibitory effect on GSDMD-N-induced pyroptosis via binding to GSDMD in the cytoplasm. Taken together, this information suggests that GSDMD may participate in caspase-1-mediated pyroptosis during I/R injury both in vivo and in vitro, which could be a potential therapeutic target to reduce brain I/R injury.