bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P723: Adaptation of Stroke Prevention Interventions for Low- and Middle-Income Countries: A Scoping Review
Authors: Ryan Nessa , Washburn Kameko , Rebello Vida , Gutierrez Desiree , Perez Hector , Drum Emily , Boden-Albala Bernadette
Published: March 2021

Introduction:
Stroke is a leading cause of mortality globally, with 85% of stroke death occurring in low- and middle-income countries (LMICs). Translation of evidence-based stroke prevention interventions from their original setting to the novel context in which they will be implemented is often unreported; especially in LMICs where it has been severely understudied. Thus, our objective was to investigate how adaptation has been examined within research on stroke prevention interventions in LMICs through a scoping review of the available literature in order to highlight benefits and best-practices, identify gaps, and develop a greater understanding of these efforts that will ultimately support attempts to address the global burden of stroke.

Methods:
This review was conducted in accordance with PRISMA-ScR guidelines. Five databases were searched (PubMed, PsycINFO, CINAHL, EMBASE, and Web of Science), for eligible studies using a search strategy developed in consultation with a research librarian. Two reviewers independently assessed the retrieved articles for selection based on the inclusion criteria (peer-reviewed empirical papers or protocols, reported on adaptation of stroke prevention interventions, and occurred in at least one LMIC) through a two phase process consisting of (1) title and abstract screening and (2) full-text screening. Discrepancies were resolved through discussion until consensus was reached. Data were charted and a narrative synthesis, guided by the FRAME framework, was used to analyze and interpret the findings.

Results:
Of 380 articles retrieved, a total of six articles reporting adaptation of primary (n=4) or secondary (n=2) stroke prevention interventions in LMICs were identified. Types of interventions included use of community health workers (n = 2), use of mHealth tools (n=2), and interventions aimed at risk factor modification (n = 2). Adaptations were proactively planned, with multiple adaptation goals reported.

Conclusions:
This is the first review of its kind to focus on adaptation of evidence-based stroke prevention interventions in LMICs. Through our systematic investigation, we highlight the need for additional research to assess the processes and outcomes of stroke prevention interventions.
Abstract P724: Perimenopausal Women With Migraine Present With Stroke at a Younger Age and With Less Comorbid Diabetes
Authors: Figurelle Morgan , Meyer Dawn M , Perrinez Emily , Rapp Karen , Wells Rebecca , Guzik Amy K , Hemmen Thomas M
Published: March 2021

Introduction:
Migraine is an independent risk factor for ischemic stroke. Frequency and severity increases in the perimenopausal period accompanied by marked vasomotor symptoms (VMS) such as hot flashes, flushing and night sweats. There is emerging evidence that VMS increases the risk of vascular disease including stroke. The purpose of this study was describe the demographics and co-morbidities of perimenopausal females with and without migraine that experience acute ischemic stroke (AIS).

Methods:
In this IRB approved study, electronic health record (EHR) data was obtained from a large, academic, comprehensive stroke center from 1/1/2015 to 1/1/2020. Inclusion criteria included female sex, age 42-65 years, and hospital diagnosis code of AIS. Hemorrhagic stroke, TIA, vasculopathy, and endocarditis associated strokes were excluded. Perimenopause was defined as age ≥42 and ≤65 years. Hormonal and menopausal status was not available in the EHR. We compared the baseline demographics and co-morbidities by ICD10 codes of subjects with and without migraine. Chi squared was used to compare categorical data and t test for continuous. Spearman rho was used to assess correlations.

Results:
We identified 660 subjects who met study criteria (n=83 with migraine; n=577 without migraine). Migraine positive subjects were significantly younger (mean age 58 vs 66 years, p=0.03) at time of AIS. Migraine positive subjects identified significantly more often as White (47%) compared to Black (10%), Asian (7%), Pacific Islander (1%), Native American/Alaskan (1%), Other/Mixed Race (31%), and unknown (3%), p=0.001. There was no significant difference in Hispanic ethnicity (p=0.87), hypertension (p=0.66), hyperlipidemia (p=0.12), or atrial fibrillation (p=0.84). Comorbid diabetes was significantly higher in the non-migraine group (94% vs 6%, p<0.001).

Conclusion:
Perimenopausal women with concomitant history of migraine present with AIS at younger ages and with lower rates of diabetes than those without a migraine history. Future research must be done to assess the correlation of menopausal symptom severity, hormone levels at time of AIS, and stroke characteristics to further understand the role of menopause in stroke risk.
Abstract P726: Cytochrome B5 Reductase 3 Modifies The Brain-Blood Axis Response To Ischemic Stroke In Mice With Sickle Cell Disease
Authors: Wood Katherine C , Schmidt Heidi M , Hahn Scott , Nouraie Mehdi , Carreno Mara , Vitturi Dario A , Ghosh Samit , Ofori-Acquah Solomon , Gladwin Mark T , Straub Adam C
Published: March 2021

Introduction:
Stroke and silent infarcts are serious complications of sickle cell disease (SCD), occurring frequently in children. Decreased nitric oxide bioavailability and responsiveness contribute to neurovascular disease. Cytochrome b5 reductase 3 (Cyb5R3) is a heme iron reductase that reduces oxidized soluble guanylate cyclase heme iron (Fe
3+
--> Fe
2+
) to preserve nitric oxide signaling. A loss-of-function Cyb5R3 missense variant (T117S) occurs with high frequency (0.23 minor allele) in persons of African ancestry.

Hypothesis:
We hypothesized that impaired reductase function of T117S Cyb5R3 exacerbates brain damage after ischemic stroke in SCD.

Methods:
Bone marrow transplant was used to create male SCD mice with wild type (SS/WT) or T117S (SS/T117S) Cyb5R3. Blood was sampled before and after middle cerebral artery occlusion (55 minutes occlusion, 48 hours reperfusion). Infarct volume (IV) was determined by 2,3,5-triphenyltetrazolium chloride. Intravascular hemolysis and correlation (Pearson’s R) of hematology changes with IV were determined. Baseline Walk-PHaSST (NCT00492531) data were analyzed for stroke occurrence.

Results:
Brain IV (63 vs 27 cm
3
, P=0.003) and mortality (3/6 vs 0/8) were greater in SS/T117S vs SS/WT. Red blood cells, hemoglobin and hematocrit declined as IV increased. Plasma oxyhemoglobin increased in parallel with IV (r = 0.74, P=0.09). There were different signatures to hematologic changes that occurred with IV in SCD. Relative to wild type, T117S contracted the erythroid compartment (red blood cell: -13% vs 13%, P=0.003; hematocrit: -20% vs 1%, P=0.008; hemoglobin: -18% vs 2%, P=0.007). Mean platelet volume correlated with IV in SS/T117S (r = 0.87, P=0.06), while the inverse occurred in SS/WT (r = -0.63, P=0.09) Monocytes increased in parallel with IV in SS/T117S (r = 0.73, P=0.16), but followed the opposite trajectory in SS/WT (r = -0.77, P=0.04). WalkPHaSST participants with T117S Cyb5R3 self-reported more ischemic stroke (7.4% vs 5.1%) relative to wild type.

Conclusion:
Cyb5R3 is an important modifier of the evolution and outcome of ischemic brain injury in SCD and its hematologic consequences. Our findings indicate a bidirectional relationship between stroke and anemia in SCD that may axially turn on Cyb5R3 activity.
Abstract P73: Imaging Markers of Brain Frailty and Outcome in Patients With Acute Ischemic Stroke
Authors: Bu Ning , Khlif Mohamed S , Lemmens Robin , Wouters Anke , Fiebach Jochen B , Chamorro Ángel , Ringelstein Erich Bernd , Norrving Bo , Laage Rico , Grond Martin , Wilms Guido , Brodtmann Amy , Thijs Vincent
Published: March 2021

Background and purpose:
Functional outcome after stroke may be related to preexisting brain health. Several imaging markers of brain frailty have been described including brain atrophy and markers of small vessel disease. We investigated the association of these imaging markers with functional outcome after acute ischemic stroke.

Methods:
We retrospectively studied patients with acute ischemic stroke enrolled in the AXIS-2 trial, an international, multicenter, randomized controlled clinical trial of Granulocyte Colony Stimulating Factor versus placebo. We assessed the ratio of brain parenchymal volume to total intracerebral volumes (i.e., the brain parenchymal fraction [BPF]) and total brain volumes from routine baseline MRI data obtained within 9 hours of symptom onset using the unified segmentation algorithm in SPM12. Enlarged perivascular spaces (EPVS), white matter hyperintensities (WMH), lacunes as well as a small vessel disease (SVD) burden were rated visually. Functional outcomes (modified Rankin Scale [mRS] score) at day 90 were determined. Logistic regression was used to test associations between brain imaging features and functional outcomes. As there was no significant effect of G-CSF on any outcomes in AXIS-2, placebo and active groups were combined for these analyses.

Results:
We enrolled 259 patients with a mean age of 69±12 years and 46 % were female. Increased BPF was associated with higher odds of excellent outcome (OR per percent increase: 1.081, 95%CI: 1.012-1.155). Total brain volumes and SVD burden were not associated with functional outcome. An interaction between BPF and large vessel occlusion on excellent outcome was not observed.

Conclusions:
Global brain health, as assessed by brain parenchymal fraction on magnetic resonance imaging, is associated with excellent functional outcome after ischemic stroke.

Clinical Trial Registration:
URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT00927836.
Abstract P730: MCA Stroke Chronically Disrupts Hippocampal Activity and Cortico-Hippocampal Communication
Authors: Ip Zachary , Rabiller Gratianne , He Jiwei , Chavan Shivalika , Nishijima Yasuo , Akamatsu Yosuke , Liu Jialing , Yazdan-shahmorad Azadeh
Published: March 2021

Introduction:
Cognition and memory deficits are common sequelae following middle cerebral artery (MCA) stroke, one of the most common strokes in humans. However MCA stroke does not compromise the structural integrity of the hippocampus, which is highly involved in memory function, because the MCA does not supply blood flow to the hippocampus. We previously reported on the acute effect of MCA stroke, where we observed increased hippocampal activity and cortico-hippocampal communication. Here we investigate chronic changes to local oscillations and cortico-hippocampal communication following MCA occlusion in rats two weeks and one month following stroke.

Hypothesis:
Cortical stroke affects remote brain regions, disrupting hippocampal function and cortico-hippocampal communication.

Methods:
We subjected male rats (n=28) to distal MCA occlusion compared to controls (n=19). We recorded local field potentials simultaneously from cortex and hippocampus two weeks and one month following stroke using 16-site linear electrode arrays under urethane anesthesia. We analyzed signal power, brain state, CFC, and sharp wave SPW-Rs to assess hippocampal function and cortico-hippocampal communication.

Results:
Our results show disruptions to local oscillations; lowered delta (1-3 Hz) signal power in the cortex and hippocampus, increased signal power in gamma (30-60 Hz) and high gamma (60-200 Hz) in cortex and hippocampus. Theta/delta brain state is disrupted, and SPW-Rs increase in power at two weeks, before returning to baseline levels at one month. Communication is also disrupted; Theta-gamma coupling, a measure of information being communicated between regions, breaks down after stroke.

Conclusions:
These results suggest that chronic stroke causes significant changes to hippocampal function, which can be characterized by these electrophysiological biomarkers, establishing putative targets for targeted stimulation therapies.
Abstract P736: Memantine, an NMDA Antagonist and Aging Alter the Thalamic Gliosis in Experimental Stroke in Mice
Authors: Kim Gab Seok , Stephenson Jessica , Wu Ting , Mamun Abdullah , Goss Monica G , Liu Fudong , Marrelli Sean P
Published: March 2021

Secondary injury in the thalamus has been observed following cortical stroke in rodents and humans and is associated with worsened recovery. Interruption of this progressive injury reflects an important therapeutic goal. However, the mechanisms whereby primary cortical infarction leads to remote injury in distant regions of brain are not well defined. We used a mouse model of cortical stroke (which demonstrates delayed thalamic injury) to define the time course of thalamic gliosis and neuronal injury and then test the potential of delayed memantine treatment (an NMDA receptor antagonist) to attenuate this secondary injury.

Methods:
Cortical infarction was induced by permanent occlusion of the distal middle cerebral artery (pdMCAO) in male C57BL/6J mice (young and aged) and CCR2-RFP mice. Brain infarct, cell-specific injury, and gliosis were measured by cresyl violet, Fluoro-jade C (FJC), TTC, FACS, and immunofluorescence. In young mice, memantine was injected at 4 and 24 hours post-stroke (100 and 50 mg/kg, ip). Brains were evaluated at post-stroke day 3 and 14 (PSD3 and PSD14).

Results:
At PSD3, the primary infarct was restricted to the cortex of the MCA territory, with no infarct detected in the thalamus of young mice. However, by PSD 14, neurons in the ipsilateral thalamus exhibited significant injury (FJC positive, condensed pyknotic nuclei). Gliosis was first detectable in the ipsilateral thalamus at PSD3 and progressively increased to PSD14 (anti-GFAP and Iba1). Infiltration of peripheral-derived monocytes was determined to be one source of the activated microglia in the thalamus (CCR2-RFP reporter mice, n=3). Interestingly, pdMCAO mice allowed to recover for two years demonstrated persistent astrogliosis (cortex and thalamus), though microgliosis was no longer evident (n=2). Aged mice subjected to pdMCAO also demonstrated gliosis in thalamus at PSD14, albeit to a lesser extent than young mice (n=5 each age). Finally, delayed treatment with memantine resulted in significantly attenuated gliosis and neuronal loss in the thalamus at PSD14 (young mice, n=9 each).

Conclusions:
These results further define gliosis in the mechanism of secondary injury and importantly demonstrate attenuation of secondary injury by delayed NMDA receptor antagonism.
Abstract P74: Risk of Covid-19 Mortality Among Patients With Preexisting Cerebrovascular Disease
Authors: Meeks Jennifer , Pan Alan , Potter Thomas , Khan Osman , Hooper Destiny , Gadhia Rajan R , Misra Vivek , Yaghi Shadi , Vahidy Farhaan S
Published: March 2021

Introduction:
COVID-19 is associated with incident cerebrovascular disease (CVD). We evaluated the association between preexisting CVD and COVID-19 mortality.

Methods:
Utilizing deidentified pooled data from 40 healthcare organizations, adult (≥ 18 years) COVID-19 patients were identified based on ICD-10 diagnostic codes and documentation of laboratory positivity for SARS-CoV-2 RNA or antibodies. Among COVID-19 patients, those with documented ICD-10 diagnoses for cerebral infarction / ischemic stroke (IS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH) and transient ischemic attack (TIA) at least 30-days before the index COVID-19 event were classified as the CVD group. The CVD and non-CVD groups were propensity score (PS) matched on demographic and comorbidity variables. Pre and post-match risk ratios (RR) and 95% confidence intervals (CI) for 30 and 90-day mortality were calculated. Mortality rates for CVD subgroups (ICH, SAH, AIS, TIA) are also reported.

Results:
Among a total of 140,034 COVID-19 cases, 4,614 (3.3%) had prevalent CVD. CVD patients were significantly older and were predominantly males of either white or black race (vs. other). CVD patients also had a higher comorbidity burden (vs. non-CVD patients) (graphic). A 1:1 PS algorithm yielded an optimally matched sample of 8,218 COVID-19 patients (4,109 CVD and non-CVD patients each). In the matched sample, 30-day mortality was 8.4% among CVD patients and 7.0% among non-CVD patients RR (CI): 1.20 (1.03 - 1.39). 90-day mortality among CVD patients (vs. Non-CVD patients) remained significantly elevated (9.7% vs. 8.2%), RR (CI): 1.20 (1.04 - 1.37). Among CVD subgroups, 30 and 90-day mortality was higher for patients with preexisting ICH (11.8% and 13.7%, respectively) compared to IS (8.7% and 10.2%, respectively).

Conclusion:
Preexisting CVD significantly increases the mortality risk in COVID-19 patients. Mechanisms for poor COVID-19 outcomes among CVD patients need to be evaluated.
Abstract P744: Gene Transcript Clusters Distinguish Time-Dependent Expression Patterns in Monocytes, Neutrophils and Whole Blood After Ischemic Stroke Injury
Authors: Carmona-Mora Paulina , Jickling Glen C , Zhan Xinhua , Hakoupian Marisa , Hull Heather , Alomar Noor , Amini Hajar , Knepp Bodie , Sharp Frank R , Stamova Boryana , Ander Bradley P
Published: March 2021

Introduction:
After ischemic stroke (IS), peripheral leukocytes infiltrate the damaged region and modulate the response to injury. We previously showed that peripheral blood cells display different gene expression profiles after IS and these transcriptional programs reflect the changes in immune processes in response to IS. Dissecting the temporal dynamics of gene expression after IS improves our understanding of the changes of molecular and cellular pathways involved in acute brain injury.

Methods:
We analyzed the transcriptomic profiles of 33 IS patients in isolated monocytes, neutrophils and whole blood. RNA-sequencing was performed on all the stroke samples as well as 12 controls with vascular risk factors (diabetes and/or hypertension and/or hypercholesterolemia). To identify differentially expressed genes, subjects were split into time points (TPs) from stroke onset (TP1= 0-24 h; TP2= 24-48 h; and TP3= > 48 h), and controls were assigned TP0. A linear regression model including time and the interaction of diagnosis x TP with cutoff of p<0.02 and fold-change>|1.2| was used. Time dependent changes were analyzed using artificial neural networks to identify clusters of genes that behave in a similar way across TPs.

Results:
Unique patterns of temporal expression were distinguished for the three sample types. These include genes not expressed in TP0 that peak only within the first 24 h, others that peak or decrease in TP2 and TP3, and more complex patterns. Genes that peak at TP1 in monocytes and neutrophils are related to cell adhesion and leukocyte differentiation/migration, respectively. Early peaks in whole blood occur in genes related to transcriptional regulation. In monocytes, interleukin pathways are enriched across all TPs, whereas there is a trend of suppression after 24 h in neutrophils. The inflammasome pathway is enriched in the earlier TPs in neutrophils, while not enriched in monocytes until over 48 hours.

Conclusion:
Our analyses on gene expression dynamics and cluster patterns allow identification of key genes and pathways at different time points following ischemic injury that are valuable as IS biomarkers and may be possible treatment targets.
Abstract P748: Transcriptome Profiling of the Neural Stem Cell Niche and the Effect of Exercise in Restoring Neurogenesis in Type II Diabetic Mice
Authors: Rabiller Gratianne , Kanoke Atsushi , Liu Jialing
Published: March 2021

Introduction:
Previously we found that mice with type 2 diabetes (T2DM) exhibited an accelerated age-associated decline in neurogenesis during baseline and after ischemic stroke compared to age-matched control mice. The current study sought to delineate the transcriptome landscape involved in the impaired neurogenesis and determine if exercise can prevent the deleterious effect of T2DM on neural regeneration.

Hypothesis:
We hypothesize that T2DM alters signaling pathways regulating neurogenesis and daily exercise mitigates the deleterious effect on neurogenesis in the T2DM mice.

Methods:
Transcriptome profiling was performed by single cell RNA sequencing (scRNAseq) of SVZ and DG cells in stroke and non-stroke mice using the 10X Genomics platform. T2DM-induced differential gene expression was analyzed by ClusterProfiler and Wikipathways enrichment analysis. Middle-aged (~260 days old) and old (~700 days old) db/+ or db/db mice were subjected to daily wheel-running exercise for one month. BrdU at 50 mg/kg twice daily for 2 consecutive days was injected i.p. at the end of the experiment to track proliferating neuroprogenitor cells. DCX+ cells and BrDU+ cells were quantified in the dentate gyrus of the hippocampus.

Results:
The scRNAseq analysis revealed multiple cell types co-existing in the neurogenic niche. GO and Wikipathways enrichment analysis showed that under diabetic condition, genes such as
Qdpr, Hsp90ab1, Hsp90aa1, and Sox9 were
downregulated in pathways involving eNOS activation; whereas
Junb, C1qc, C1qb and C1qa were upregulated
in the pathways related to oxidative stress. Exercise, known to increase eNOS expression and reduce oxidative stress-induced cell death, significantly restored the number of DCX+ immature neurons in 8-months-old diabetic mice almost to the level of the control mice without exercise

Conclusions:
Exercise restores neurogenesis by increasing the number of neuroblasts in the middle-aged diabetic mice. Ongoing experiment will investigate whether exercise promotes neurogenesis by enhancing eNOS and improved blood flow, and inducing genes involved in the survival of the NSC niche of the diabetic mice.
Abstract P754: Prothrombotic and Proinflammatory Milieu in Diabetic and Non-Diabetic Stroke Cohort - Using Coated-Platelets and Peripheral Blood Indices
Authors: Ray Debarti , Xu Chao , Ray Bappaditya , Prodan Calin I
Published: March 2021

Introduction:
Elevated levels of coated-platelets (a subset of procoagulant platelets) are often associated with acute ischemic stroke (AIS). In addition, diabetes mellitus (DM) and chronic inflammation are known risks factor for AIS. Elevated neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) [markers of inflammation] are also reported in AIS. However, prothrombotic and proinflammatory states among DM patients with different AIS subcategories is not known.

Hypothesis:
To investigate whether coated-platelet levels, NLR and/or PLR among DM and non-DM AIS patients differ.

Methods:
We studied AIS or transient ischemic attack (TIA) over the period of 1.5 years and AIS (classified as per TOAST criteria). Coated-platelet levels were assayed at admission. Glycated hemoglobin (HbA1c) and leukocyte count with differential were studied. Study population was subcategorized into DM (HbA1c >6.4 and/or DM history) and non-diabetic (HbA1c <6.4). We examined the difference of coated-platelet levels and other continuous variables between groups using Wilcoxon rank test at significance level of 0.05.

Results:
Our cohort of 60 AIS/TIA patients were 67.0± 7.8 years in age and 23 (38.3%) were current smokers. Thirty-six (60.0%) had DM. Coated-platelet levels of AIS patients with DM [due to large artery atherosclerosis (LAA), cardioembolism (CE) and lacunar etiology] was non-significantly higher than similar cohort without DM [36.8±13.6 vs. 30.9±10.2 (p=0.068)]. Among diabetic AIS patients with LAA, higher levels of coated-platelets was observed compared to rest of the DM patients [42.1±16.0 vs. 31.9±11.3 (p=0.021)]. PLR among AIS patients with DM due to CE etiology was significantly higher as compared to diabetic patients in rest of the cohort [186.3±69.6 vs. 111.7±39.1 (p=0.0002)]. Diabetic AIS patients with LAA had significantly lower PLR as compared to others with DM [98. 5±21.4 vs. 138.8±58.1 (p=0.042)].

Conclusion:
Diabetic patients with AIS due to LAA have higher procoagulant platelets and lymphocytosis (decreased PLR), suggestive of chronic inflammation, whereas those with CE etiology have lymphopenia (increased PLR) suggestive of acute inflammation.
Abstract P756: Bilirubin Oxidation and Cerebral Vasospasm in Subarachnoid Hemorrhage: A Feasibility Study
Authors: Gordon Weston R , Goswami Shweta , Yang Jane , Yekzamen Bailey , Abraham Michael G , Shapiro Steven M
Published: March 2021

Introduction:
Cerebral vasospasm (CV) following aneurysmal subarachnoid hemorrhage (aSAH) is associated with a high degree of morbidity and mortality. In an adequate oxidative environment, certain products of bilirubin metabolism have been hypothesized to be a cause of CV. To our knowledge no prospective CSF collection has been performed to establish a time course for their formation in the clinical context of CV. We aimed to design a pilot study assessing the feasibility of collecting and storing CSF for analysis of potential biochemical markers for CV, and to evaluate which variables can accurately and reliably be measured for a larger prospective study.

Methods:
Adult patients with aSAH and an external ventricular drain (EVD) were enrolled. Patients who had complications following treatment of aSAH or who developed any neurological deterioration unrelated to the aSAH were excluded. CSF was extracted from patients on the initial day of EVD placement and then daily for a total of 10 days and frozen until data analysis. Heme, Heme Oxygenase (HO-1) and Cu/Zn-Superoxide Dismutase (SOD) were measured using commercially available assay kits.

Results:
Patients 1, 2 and 3 had modified Fisher grades of 2, 3 and 4, respectively. Patients 1 and 3 underwent endovascular coiling and patient 2 had surgical clipping. There were no complications and no CV. Heme concentrations were 40.0 ± 8.5 μm, 55.6 ± 7.7 μm, and 64.7 ± 0.4 μm on day of bleed (day 0) for patients 1, 2, and 3, respectively, and decreased in patients 1 and 2 on day 1. SOD concentrations peaked on day 2 for patient 1 (140.2 ± 15.6 ng/mL), on day 0 for patient 2 (25.8 ± 14.9 ng/mL), and on day 1 for patient 3 (215.9 ± 24.4 ng/mL). HO-1 concentrations peaked for all three patients on day 2 (14.6 ± 0.4, 17.6 ± 12.0 and 23.6 ± 5.4 ng/mL, respectively).

Conclusions:
The study was successful in completing our objective of establishing a protocol for collection, storage, and measurement of three potential biochemical markers in CSF. A larger prospective study will be performed to establish the time course of bilirubin metabolism and oxidation in the CSF relative to the clinical condition of CV in patients after aSAH.
Abstract P757: Social Isolation After Stroke Reduces Cell Proliferation and Alters Brain MiRNA Profiles in the Aged Female Mice
Authors: Holmes Aleah , Xu Yan , Lee Juneyoung , Zhu Liang , Venna Venugopal Reddy , McCullough Louise D
Published: March 2021

Background:
Social isolation (SI) and loneliness are risk factors for stroke. Epidemiological studies have shown that women tend to have a higher risk of stroke at later age and elderly women are more likely to be isolated. The mechanisms underlying the detrimental effects of SI have not been well studied in older females. We hypothesized that SI in aged female mice would lead to impaired post-stroke recovery and could lead to differential regulation of microRNAs (miRNAs).

Methods:
In this study, aged C57BL/6N female mice were subjected to a 60-minute middle cerebral artery occlusion (MCAO) and were randomly assigned to either single housing (SI) or continued pair housing (PH) immediately after stroke for 15 days. Infarct size, mortality and recovery was assessed using open field, the adhesive-tape removal task and the Y-maze test. MiRNAs were comprehensively analyzed by miRNAome analysis on stroke brain, and changes in hippocampal cell proliferation was assessed from perfused brain sections.

Results:
Importantly, SI immediately after stroke led to significantly larger tissue loss and higher mortality in aged females, it also significantly delayed motor/sensory recovery in the adhesive removal test and impaired overall locomotor activity. In addition, these mice also demonstrated worse post-stroke cognitive function. In parallel, brains of these mice showed reduced miR-297a-3p expression and increased miR-18a-3p and miR-200c-3p expression with SI compared to PH cohort and reduced hippocampal cell proliferation.

Conclusion:
The results from this study suggest that SI after stroke can increase mortality and significantly impair post-stroke recovery in aged female mice. These worse outcomes are in parallel to the significant changes in several miRNAs and reduced hippocampal cell proliferation.
Abstract P76: Effect of Covid-19 Pandemic on Acute Ischemic Stroke Hospitalizations Among Medicare Beneficiaries in the United States
Authors: Yang Quanhe , Tong Xin , Coleman King Sallyann , Merritt Robert K
Published: March 2021

Introduction:
Emergency department visits and hospitalizations for acute ischemic stroke (AIS) declined significantly following the declaration of COVID-19 as a national emergency on March 13, 2020 in the United States. No study has examined the volume and nature of AIS hospitalizations among older adults in the U.S. amidst the COVID-19 pandemic. This study examined the trend and compared the characteristics of Medicare fee-for-service (FFS) beneficiaries ≥65 years hospitalized with a primary AIS diagnosis in the same timeframe before and after the COVID-19 pandemic.

Methods:
We included hospitalizations with a primary diagnosis of AIS (ICD-10 I63) among Medicare FFS beneficiaries from week 11 to 24 in 2019 and 2020. We estimated the percent reduction of AIS hospitalizations between 2019 and 2020 by age, sex, race/ethnicity, and state. We tested for difference in distribution by age group, sex and race/ethnicity between 2019 and 2020 based on χ
2
test.

Results:
During the 14-weeks from March 8 to June 13, 2020, AIS hospitalizations among FFS beneficiaries were reduced by 23.7% compared to weeks 11 to 24 in 2019 (March 10 to June 15) (49,607 in 2019 vs. 37,860 in 2020). A greater percent reduction in AIS hospitalizations was observed with older age (27.2% among ≥85 years vs. 20.6% among persons 65-74 years, p<0.001). The magnitude of reduction was similar between men (23.8%) and women (23.6%, p=0.791), and among non-Hispanic white (24.2%), non-Hispanic black (22.4%), Hispanic (19.3%), and other (22.4%, p=0.189). AIS hospitalization trends varied by state ranging from 1.6% in New Hampshire to 39.8% in Montana.

Conclusion:
Hospitalizations with a primary AIS diagnosis among Medicare FFS beneficiaries were reduced by 24% during weeks 11 to 24 of the COVID-19 pandemic compared to the previous year in the United States. AIS hospitalization reductions varied substantially by state. Further study is needed to examine the long-term effects of COVID-19 pandemic on stroke outcomes.
Abstract P770: An Mri-Based Method for Assessing the Extent and Location of Bleeding in a Rat Model of Subarachnoid Hemorrhage
Authors: Butler Mitchell , Geraghty Joseph R , Sudhakar Deepshika , Lung Tyler , Testai Fernando , Loeb Jeffrey
Published: March 2021

Objective:
Studies in subarachnoid hemorrhage (SAH) animal models are limited to early timepoints, after which the brain is extracted to confirm hemorrhage. For long-term studies, blood is resorbed by the time of euthanasia and thus alternative methods of confirming SAH are necessary. Here, we used
in vivo
MRI to determine the presence, extent, and location of blood in the endovascular perforation rat model of SAH.

Methods:
Animals were divided into two groups - SAH and sham controls (no perforation). Rats were imaged at 24 hours in a 9.4T MRI scanner. T2-weighted imaging (T2WI) was used to quantify and localize the volume and extension of blood. T2WI was performed with a fast spin echo sequence with TR/TE = 5000/60 ms, FOV = 40x40 mm
2
, 0.75 mm slice thickness, and no interslice gap. SAH was identified as hypointense signal at the skull base, a normally hyperintense region due to cerebrospinal fluid in the basal cisterns. Regions of interest were identified and segmented manually. Pixels were converted to areas, and the total hypointense volume (V
hypo
) was computed by summing all areas. V
hypo
was normalized to total brain volume (TBV) for each animal. Ability to detect blood via MRI was compared to the gold standard of direct visualization of blood after brain extraction using receiver operating characteristic (ROC) curves. The location of blood was plotted along a standardized antero-posterior axis. 3D reconstructions were developed in 3D Slicer to visualize the spatial distribution of hemorrhage.

Results:
V
hypo
values were 1.6±1.4 mm
3
sham (n = 8) and 7.5±3.9 mm
3
for SAH (n = 10) [p=0.0003]. This difference persisted when V
hypo
was normalized to TBV (p=0.0005). There was no difference in the TBV between groups (p=0.1493). V
hypo
distinguished between SAH and sham animals (p=0.001, area under curve = 0.963). A cutoff of V
hypo
= 4.63 mm
3
corresponded to 100% specificity and 80% sensitivity for confirming SAH. The spatial distribution of bleeding varied along the antero-posterior axis within the subarachnoid space.

Conclusions:
We developed an
in vivo
MRI method for the quantification of SAH blood volume and location in rats. This will be used for future long-term studies to confirm and grade severity of SAH.
Abstract P774: Therapeutic Efficacy of Next Generation Anti-miR-141-3p for Ischemic Stroke
Authors: Dhuri Karishma , Blumenfeld Leslie , Bahal Raman , Verma Rajkumar
Published: March 2021

Background:
Stroke and factors modifying stroke responses, such as social isolation, increases miR-141-3p. Hence, inhibiting miR-141-3p can be a promising stroke therapy. Unfortunately, commercially available miR-141-3p inhibitors cannot be used for therapeutic purpose due to several limitations; use of viral or non-viral transfection reagents for cell penetration,
in vivo
instability of anti-miRs and toxicity of synthetic anti-miRs. Therefore, we explored phosphorothioates (PS) and peptide nucleic acids (PNAs) based anti-miR-141-3p encapsulated in poly (lactide-co-glycolide) (PLGA)-based nanoparticles (NPs) for potential stroke therapy.

Methods:
PNAs and PS anti-miR 141-3p were synthesized in house using solid phase synthesis and purchased from a commercial vendor, respectively. The anti-miRs were encapsulated in PLGA NP by double emulsion solvent evaporation technique. For in vivo efficacy 8-10 weeks old C57BL/6 male mice were pair-housed (PH) for at least two weeks. After two weeks, a 60-minute right middle cerebral artery occlusion surgery (MCAO) was performed and mice were kept individually. The mice were then randomly assigned to receive NPs of either anti-miR-141-3p PNA or anti-miR-141-3p phosphorothioate (PS) or scrambled control (Sc) through lateral tail vein 4 hrs. after stroke. To measure NPs of PS were conjugated with fluorophore (TAMRA) to measure BBB permeability. The effect of inhibitor treatment was evaluated at 3 days after stroke.

Results:
The formulated NPs show uniform morphology with a mean dry particle size <120 nm and an average hydrodynamic diameter of 350 nm. The NPs exhibit an average polydispersity index of 0.1-0.2 indicating homogenous particle size distribution. Single dose of anti-miR 141 and (NPs containing 0.05mg/kg i.v of total either PNA or PS) Both the NPs of PNA and PS significantly reduced (P<0.05 vs. Sc) infarct injury and neurological deficit. Anti-miR of PNA and PS reduce 6 and 5-fold respectively of miR-141-3p in the brain tissue.

Conclusion:
Our NPs are BBB permeable. PNA based anti-miR-141 are more potent the PS based anti-miR Reduced miR-141-3p levels as well as infarct injury by both PS and PNA based anti-miR 141-3p suggest the efficacy of our novel ant-miR -141-3p for the treatment of ischemic stroke.
Abstract P778: Hypertension and Vascular Cell Adhesion Molecule 1 Relate To % Change in National Institutes of Health Stroke Scale Score in Ischemic Stroke After Mechanical Thrombectomy
Authors: Maglinger Benton , Sands Madison , Frank Jacqueline , Trout Amanda L , Roberts Jill , Grupke Stephen , Turchan-Cholewo Jadwiga , Stowe Ann M , Fraser Justin , Pennypacker Keith
Published: March 2021

Introduction:
The University of Kentucky Blood and Clot Thrombectomy Registry and Collaboration (BACTRAC) protocol utilizes thrombectomy to isolate intracranial (i.e. distal to thrombus) arterial blood and systemic (i.e. carotid) arterial blood from thrombectomy procedures to study stroke. Here, we investigate the relationship among Vascular Cell Adhesion Molecule 1 (VCAM1), hypertension (HTN), and stroke recovery in patients undergoing mechanical thrombectomy for emergent large vessel occlusion (ELVO) stroke.

Methods:
Intracranial and systemic plasma samples from 25 subjects underwent cardiometabolic proteomic analysis at Olink Proteomics. Demographic data including HTN status and both admission NIHSS and discharge NIHSS were included. Linear regression analysis was run on both intracranial and systemic VCAM1 expression levels against % change in NIHSS ((Admittance NIHSS - Discharge NIHSS)/Admittance NIHSS)) and two-tailed t-tests were run assessing VCAM1 expression with HTN vs. no HTN.

Results:
Increased expression of intracranial VCAM1 significantly correlated with a smaller % change in NIHSS (p=0.001). Similarly, increased systemic VCAM1 expression was also found to have a significant relationship with smaller % change in NIHSS (p=0.005). Subjects with hypertension had significantly higher intracranial (p=0.03) and systemic (p=0.001) VCAM1 levels compared to those without HTN.

Discussion:
VCAM1 mediates leukocyte-endothelial cell adhesion and has been shown to play a role in stroke. This study takes a novel approach of sampling both intracranial and systemic arterial blood during an ELVO stroke. We found increased intracranial and systemic VCAM1 independently correlate with a smaller % change in NIHSS, an indicator of poorer initial recovery. Although preliminary, these results suggest an informative role of VCAM1 levels at the time of infarct. Additionally, those with HTN had higher levels of intracranial and systemic VCAM1. These data are in line with previous studies suggesting VCAM1 is a marker of endothelial damage due to HTN leading to negative clinical outcomes. To better understand our findings, we plan to perform subset analyses investigating VCAM1 levels in relation to dyslipidemia, infarct time and infarct volume.
Abstract P779: Monocyte to Lymphocyte Ratio in Clot Analysis is a Marker of Cardioembolic Stroke Etiology
Authors: Juega Jesus , Pagola Jorge , Palacio Carlos , deck matias , Rodriguez maria teresa , Requena Manuel , Garcia-Tornel Alvaro , Olivé MArta , Rodriguez-villatoro Noelia , Rodriguez-luna David , Rubiera Marta , Muchada Marian , boned sandra , Ribo Marc , Sanjuan Estela , Pancorbo Olalla , carlos pinana , Hernandez David , Coscojuela Pilar , Hernandez MAria , Dorado Laura , carolina.delatorre@gmail.com Carolina , Cardona Pedro , QUESADA HELENA , Camacho Jessica , Ramon y Cajal Santiago , Alvarez-Sabin Jose , MOLINA Carlos A
Published: March 2021

Methods:
We analyzed data from 190 patients in a prospective unicentric study. Thrombi obtained in emergent endovascular treatment ( EVT) were analyzed by MFC order to calculate the percentage of granulocytes , monocytes and lymphocytes, over total leukocyte population as well as monocyte-to-lymphocyte ratio ( MLR) Clinical and interventional parameters were recorded for each patient. Stroke subtypes were defined by the Trial of ORG 10172 in Acute Stroke Treatment classification. We tested MFC predictors of high risk cardioembolic strokes (HR CE) in patients with undetermined stroke etiology . MFC predictor was obtained by comparison of clots due to Large Arterial Atherosclerosis compared with clots due to HR CE.

Results:
Among 190 clots retrieved, 163 cases were properly analized. 91 cases with known stroke etiology after EVT and 72 cases of Undetermined stroke. In a demographic (age, gender) and EVT matched (time, tpa, number of passes) case -control study of 56 patients: HR CE strokes (28 cases) and LAA strokes (28 cases), the proportion of monocytes ( OR 1.06 , 95% CI 1.01- 1.11) and MLR ( OR 1.83 , 95% CI 1.12- 2.98) independently predicted HR CE detection. A cut-off point of 1.77% in a receiver operating characteristic curve predicted cardiomebolic etiology with sensitivity of 71% and specificity of 82%. Among Undetermined Strokes (n=72) the percentage of HR CE detection was higher in patients with high MLR (n=40 ; 74%) compared with low MLR (n=6; 33%) ( p< 0.001). Patients with high MLR were older than low MLR cases, although MLR > 1.77 independently predicted HR CE detection among Undetermined strokes (OR, 4.50 ,95% CI 1.35-15.04) in a multivariate model adjusted for age.

Conclusion:
Measurement of monocyte to lymphocyte ratio in clots by multiparametric flow cytometry detected patients at high risk of hidden cardioembolic origin among undetermined stroke population.
Abstract P78: Shared Genetic Background Between Sars-CoV-2 Infection and Ischemic and Hemorrhagic Stroke
Authors: Parodi Livia , Myserlis Evangelos Pavlos , Chung Jaeyoon , Henry Jonathan , Montgomery Bailey , Rosand Jonathan , Anderson Christopher D
Published: March 2021

Background:
Recent reports have emerged linking SARS-CoV-2 infection to neurological diseases including stroke. It is unclear whether cerebrovascular disease and SARS-CoV-2 share a common risk mechanism, or whether the specific host response to SARS-CoV-2 increases the risk of stroke. We sought to investigate whether genes and pathways associated with SARS-CoV-2 infection and its systemic host response are also related to risk of ischemic stroke (IS) and intracerebral hemorrhage (ICH).

Methods:
We constructed gene-sets involved with SARS-CoV-2 infection risk and host response. Brain-specific datasets (ROSMAP and Braineac) were used to build co-expression networks for 5 target genes (
ACE2
,
TMPRSS2
,
BEST3
,
ISLR2
and
ADAM17
) involved in SARS-CoV-2 infection phase. Host response gene-sets were constructed from SARS-CoV-2 post-infection gene expression networks measured from lung, kidney, and blood, extracted from literature review. Gene-based association testing was performed using VEGAS2 on GWAS summary data, as well as on data generated through S-PrediXcan analysis of primary tissues relevant to ICH/IS/subtypes. Fisher’s exact test was used to examine gene-set enrichment.

Results:
The SARS-CoV-2 risk-related
ISLR2
co-expression gene network was significantly associated with genetic risk of the large artery stroke (LAS) subtype, across tissues in multiple brain regions (3/10, FDR-p ≤ 0.05), as well as in LAS-relevant primary tissues such as aorta and tibial arteries (p ≤ 0.05). Among SARS-CoV-2 host response factors, SARS-CoV-2 expression changes in lung were found to be enriched for all-cause ischemic stroke risk (p = 0.03), while lobar ICH risk showed an enrichment (p = 0.04) for genes expressed during antiviral response in the blood compartment.

Conclusion:
Gene networks specific to SARS-CoV-2 infection suggest enrichment in pathways related to infection and host response in both IS and ICH, informed by gene expression levels in multiple brain tissues. Collectively, these findings suggest that increases in stroke risk reported in patients with SARS-CoV-2 infection, particularly large artery stroke, may be intrinsic to this viral infection rather than a more generalized response to severe illness.
Abstract P782: Bioimpedance as a Means to Quantify Clot Composition and Guide Selection of Thrombectomy Devices
Authors: Liu Yang , Bhambri Ankur , Adapa Arjun , Shih Albert , Pandey Aditya
Published: March 2021

Introduction:
Recent studies suggest that suction based thrombectomy leads to better recanalization with RBC-rich clots while stent-retrievers perform better with fibrin-rich clots. The ability to determine real-time histology of clots, in the setting of large vessel occlusion (LVO), could potentially lead to improved recanalization and better clinical outcomes while simultaneously reducing procedural costs. There is an unmet need for technology that would allow for accurate assessment of real-time clot histology in LVOs.

Hypothesis:
Bioimpedance measurements can be used to predict real-time clot histology.

Methods:
We constructed an in vitro test bed to measure the bioimpedance of clot analogs with different RBC percentages. The test bed includes a cylindrical chamber with a gold electrode embedded at the bottom. A mixture of human RBCs and plasma was injected into the chamber and coagulation was induced by adding calcium chloride solution. After coagulation, another gold electrode was used to sandwich the clot. Both electrodes were connected to an inductance, capacitance, and resistance (LCR) meter and a low-voltage (10 mV) excitation was sent to the clot at 1 to 201 kHz. We fabricated 5 types of clot analogs by mixing human RBCs and plasma with different RBC percentages (10%, 30%, 50%, 70%, and 90%). Clot types were measured 3 times. The Pearson correlation coefficient was calculated and used to evaluate the relationship between clot bioimpedance and RBC percentage.

Results and Conclusions:
Clot impedance decreases with the excitation frequency and clots with higher RBC percentages had higher impedance at all excitation frequencies (Fig. 1). The impedance was strongly and positively related to the RBC percentage (
r
= .996,
p
= .0004). By minimizing the electrode size and integrating them into catheters, stents, or wires, such technology could inform clinicians of clot composition and guide device selection for optimum recanalization.
Abstract P786: Effect of Age and Stroke on Purinergic Receptor P2x4 (p2x4r) Expression in Human Monocyte Subsets
Authors: Verma Rajkumar , DiMauro Sharon E , Blumenfeld Leslie , Srivastava Pranay , Mittal Sanjay , Bulsara Ketan R , Liang Bruce T
Published: March 2021

Backgrounds:
An acute ischemic stroke (AIS) triggers rapid infiltration of circulating immune cells in the brain. P2X4R, a receptor for adenosine triphosphate ATP, regulate activation of circulating monocytes after stroke injury. Over-stimulation of P2X4R contributes to ischemic injury. CD14
++
CD16
–
classical, CD14
++
CD16
+
intermediate, and CD14
+
CD16
++
non-classical monocytes are three primary subsets of monocytes. Alterations in activity of circulating monocyte subsets may independently predict pathogenesis of AIS, however, the role of P2X4R in the activation of these monocyte subsets is not known.

Methods:
Consecutive AIS patients (60-90 years) undergoing endovascular clot retrieval and healthy control subjects both young (18-45 years) and aged (60-90 years) of both sexes were recruited and informed consent obtained. Flow cytometric analysis of whole blood derived monocytes at 0-2 days (acute, n=10), 3-7 days (subacute, n=9), and 65±20 days (chronic, n=7) after stroke onset were compared with healthy subjects (n=9-10/ age group).

Results:
Both number of total monocyte counts and P2X4R intensity significantly increase with age when compared between healthy young and aged control (P<0.05). Total monocyte count progressively increased during recovery in AIS patient (P<0.05). No. of CD14
++
CD16
+
intermediate monocytes were significantly reduced after stroke (
p
<0.05). Both CD14
++
CD16
+
intermediate, and CD14
+
CD16
++
non-classical monocytes showed a significant increased median fluorescent intensity (P<0.01) of P2X4R at subacute and chronic time after AIS.

Conclusions:
P2X4R expression increases with age and after stroke. Disappearance of the CD14
+
CD16
++
non-classical monocyte subpopulation from circulation during stroke recovery suggests potential migration of these cells to the site of injury, consistent with their potential role in inflammation/phagocytosis. Increased P2X4R expression in intermediate and non-classical monocytes subpopulation suggest its specific role in selective activation of these monocytes subtype. Detailed molecular characterization of P2X4R response in intermediate and non-classical monocyte subpopulations may provide novel insights into P2X4R’s therapeutic potential during AIS.