bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract TP447: Angiotensin II Increases Glymphatic Flow Through a Norepinephrine-dependent Mechanism
Authors: Russak Adam , Vates G. Edward , Plog Benjamin , Nedergaard Maiken
Published: July 2021

Background and Objective:
The CNS possesses the astrocyte-dependent perivascular glymphatic pathway to facilitate CSF-ISF exchange and clearance of interstitial wastes. Cerebral arterial pulsations drive glymphatic flow, and cerebrovascular pulsatility is dependent, at least in part, on systemic blood pressure. Renin-angiotensin-aldosterone axis dysregulation is responsible for hypertension, a condition that affects nearly 30% of the US population and 40% of individuals globally. Here, we investigate how manipulation of the RAA axis, both with angiotensin and common anti-hypertensive pharmacotherapy, influences glymphatic flow.

Methods:
All drugs were administered to the cisterna magna via cannulation at a rate of 1 μL/min for a total volume of 5 μL. Immediately after, 1% AlexaFluor-555 conjugated bovine serum albumin (BSA-555) was delivered intracisternally at a rate of 2 μL/min for a total volume of 10 μL. 30 minutes following tracer injection, cerebral tissues were collected and processed for ex vivo conventional fluorescence microscopy. Tissue area occupied by fluorophore was quantified, with greater percent areas indicating increased glymphatic influx.

Results:
Pre-treatment with Angiotensin II (ATII, 1 μM) increased glymphatic influx relative to vehicle-injected controls. Losartan (1 μM), an AT1 receptor inhibitor, was found to decrease glymphatic CSF influx, indicating that ATII acts through the AT1 receptor to increase glymphatic flow. Systemic administration of DSP-4 (50 mg/kg), a neurotoxin known to deplete locus coeruleus norepinephrine, resulted in suppressed glymphatic influx. Co-administration of ATII in DSP-4 treated mice or in mice receiving a norepinephrine inhibitory cocktail (1 μM) resulted in decreased glymphatic influx, suggesting that ATII regulates glymphatic pathway function through a NE-dependent mechanism.

Conclusions:
Angiotensin II acts via the AT1 receptor to increase glymphatic influx in a norepinephrine-dependent manner. Further study on hemodynamic regulation of glymphatic flow may reveal mechanisms of hypertension-related brain pathology.
Abstract TP456: Coated-platelets Levels After Subarachnoid Hemorrhage Predict Post-discharge Short-term Cognitive Outcome
Authors: Ray Bappaditya , Pandav Vijay M , Mathews Eleanor A , Thompson David M , Traore Aminata A , Chaudhary Shuchi , Bohnstedt Bradley N , Dale George L , Prodan Calin I
Published: July 2021

Introduction:
Delayed cerebral ischemia (DCI) is a determinant of short-term and long-term morbidity after subarachnoid hemorrhage (SAH). DCI is likely due to neurohumoral activation and inflammation-thrombosis cross-talk during the acute phase. Coated-platelets (CP), a subset of procoagulant platelets, contribute to systemic thrombogenicity and are associated with recurrent ischemic stroke.

Hypothesis:
We hypothesized that high CP levels during first 3 weeks of SAH (acute hospitalization) would be associated with worse short-term clinical outcome.

Methods:
A prospective cohort of 28 patients with post-discharge clinical follow-up (average 12 weeks) was studied. Outcomes were assessed using modified Rankin Scale (mRS) and Montreal Cognitive Outcome Assessment (MOCA). Blood samples to measure CP levels were performed - 1) during acute hospitalization and 2) at follow-up visit (defined as patient’s baseline). Trend of CP during acute hospitalization was analyzed against weighted mean baseline CP level to test hypothesis.

Results:
Average age of cohort was 52.6±12.2 years with 71.5% women. During acute phase 9 (32.1%) patients developed symptomatic vasospasm and 14 (50%) had DCI on imaging. Baseline CP levels did not differ (p=0.118) between patients with MOCA ≥26 (41.3%, n=13) and MOCA <26 (29.5%, n=15). However, patients with MOCA <26 had significantly higher CP levels during first 5 days than baseline (50.4% vs 29.5%, p=0.0004). These levels decreased by 1.77%/day from 6-21 days as compared to 1.55%/day for patients with MOCA ≥26 (p=0.723). In contrast, 20 (71.4%) patients with mRS 0-2 had average baseline CP levels of 37.3% vs 8 (28.6%) with mRS 3-6 having CP levels of 31.7%. For patients with mRS 0-2 and mRS 3-6, CP levels increased from baseline during first 5 days after SAH by 10.3% and 16.5% respectively (not statistically significant). Rate of CP decrease during 6-21 days was 1.43%/day and 2.02%/day (p=0.259) for mRS 0-2 and mRS 3-6 respectively.

Conclusion:
Elevated CP levels during the acute phase of SAH are strongly associated with lower MOCA scores at 12 weeks but not with higher mRS assessment. These results suggest that increased thrombogenicity after SAH leads to cognitive impairment despite good physical outcomes.
Abstract TP6: Prediction of Clot Fragility and Recanalization Outcome Using Susceptibility Vessel Sign on Susceptibility Weighted Image
Authors: Kang Dong-Wan , Jeong Han-Gil , Kim Chi Kyung , Kim Jun Yup , Kim Do Yeon , Pyun Jung Min , Lee Seung-Hoon
Published: July 2021

Introduction:
Susceptibility vessel sign (SVS) on T2*-weighted imaging (T2*WI) is associated with a high proportion of RBCs. Susceptibility weighted imaging (SWI) is more sensitive to visualize SVS than T2*WI, resulting both RBC- and platelet-rich thrombi detectable. Clot composition and burden impact the success of recanalization therapy, but how SVS influences the likelihood of recanalization is still debated.

Hypothesis:
We assessed the hypothesis that increased conspicuity of SWI-SVS reflects high proportion of RBCs and subsequent recanalization by endovascular treatment.

Methods:
From total of 143 ischemic stroke patients who was performed endovascular treatment between February 2010 and June 2015, the authors collected eligible cases with the following inclusion criteria; (1) SWI performed before endovascular treatment (N=123); (2) intracranial portion of ICA, MCA, and ACA occlusion (N=93). We excluded 4 cases with SWI of poor quality and analyzed 89 cases. Clinical information including stroke subtype, use of rt-PA, and time from puncture to recanalization was analyzed. All MR images and angiographies were analyzed for the presence, location, diameter, length, and volume (diameter*length) of SWI-SVS, and TICI grade.

Results:
Female was 47.2% (n=42) and mean age was 68.4±13.2. SWI-SVS was identified in 77.5% (n=69) of patients. SWI-SVS was more commonly associated with cardioembolism (CE; 49 of 57, 86.0%) than with other stroke subtypes (20 of 32, 62.5%;
P
=0.011). SVS length (11.20±7.96 vs. 6.90±7.03 mm;
P
=0.013) and diameter (4.72±2.53 vs. 2.48±2.21 mm;
P
<0.001) were longer in CE group than the other. SVS diameter was longer in recanalization group (TICI≥2b) than in non-recanalization group (4.21±2.63 vs. 2.82±2.42 mm;
P
=0.040). Multivariate analysis showed that SVS diameter and volume were independent predictors of CE and recanalization, respectively (OR, 1.67 and 1.02; 95% CI, 1.15-2.41 and 1.00-1.04;
P
=0.007 and 0.005).

Conclusions:
Diameter and volume of SWI-SVS can predict cardioembolic stroke and recanalization, respectively. It may be useful for choosing the optimal treatment based on clot composition.
Abstract TP66: Single Slice Maximal Lesion Diameter Predicts Malignant Pattern of Diffusion Lesions in Acute Ischemic Stroke
Authors: Wouters Anke , Dupont Patrick , Kufner Anna , Lemmens Robin , Thijs Vincent
Published: July 2021

Introduction:
Recent endovascular trials excluded patients with large ischemic cores on diffusion-weighted imaging (DWI) or perfusion CT using automated volumetric analysis.

Hypothesis:
We investigated whether the largest diameter of the DWI lesion measured on a single slice could accurately predict large ischemic cores, as defined by automated volumetric analysis; such findings could result in a simple tool for predicting clinical outcome.

Methods:
Magnetic resonance imaging data from the multicenter AXIS 2-trial were used. Patients were included within 9h of symptom onset and received intravenous thrombolysis if eligible. The maximum diameter of the diffusion lesion was measured on the slice with the largest lesion extension. Maximum diameters on a single slice were compared with the volumes of > 50 ml, >70ml and >100ml determined by standard volumetric analysis. We also assessed whether and for which threshold, largest lesion diameter was a predictor of poor clinical outcome defined as modified ranking scale (mRS) 5 or 6.

Results:
A total of 304 patients were included of which 50 (16%) presented with a carotid occlusion. 96 (32%) patients had a DWI-volume of more than 50 ml, 63 (21%) more than 70ml and 46 (15%) more than 100ml. A diameter of respectively 5.5, 6.5 and 7 cm on a single slice with the largest lesion extension was the best predictor of a DWI lesion volume of more than 50 (sensitivity (sens) 97%, specificity (spec) 80%), 70 (sens 95%, spec 83%) and 100ml (sens 100%, spec 85%). The maximum diameter was a reasonable predictor of poor clinical outcome with an AUC of 0.76 (95%CI: 0.68-0.83). The optimal cut off point was found to be 5.5 cm (sens 71%, spec 67%).

Conclusion:
Measuring the maximum lesion diameter on a single slice on DWI identifies patients with large ischemic cores with a high sensitivity and specificity. This finding can be useful in clinical practice and for future clinical trials where rapid and uniform decision making to exclude patients with a malignant profile from endovascular therapy is essential.
Abstract TP73: Lower Prehospital Blood Pressure Is Not Associated with Larger Infarct Volumes in Non-lacunar Ischemic Stroke Patients
Authors: Zewude Rahel T , Gioia Laura C , Kate Mahesh , Liss Kim , Rowe Brian , Butcher Ken
Published: July 2021

Background:
Although prehospital blood pressure (BP)-lowering trials in acute stroke have begun, concerns persist that hypotension may exacerbate hypoperfusion and increase infarct volumes, particularly in non-lacunar stroke. We tested the hypothesis that lower prehospital BP is associated with larger infarct volumes in non-lacunar ischemic stroke.

Methods:
We conducted a retrospective study of consecutive patients with suspected stroke transported by Emergency Medical Services (EMS) during an 18-month period. Serial prehospital BP data were obtained from a centralized EMS database. Hospital charts and neuroimaging were reviewed. Stroke etiology was classified using TOAST criteria. Infarct volumes were measured on follow-up MRI or CT using semi-automated thresholding planimetric techniques by two independent raters, blinded to prehospital BP.

Results:
Of a total 960 patients transported by EMS, 367 had a final diagnosis of ischemic stroke. Stroke etiology was large artery disease in 51 patients, cardioembolic in 140, lacunar in 44, other determined etiology in 22, and cryptogenic in 110 patients. Follow-up imaging was available in 315 patients (163 MR, 152 CT) at a median (IQR) 1(1) days. The overall median non-lacunar infarct volume was 16.5 (49.6) ml, median NIHSS was 7(10), and mean prehospital SBP was 153 ± 25 mmHg. Mean prehospital SBP was lower in patients with other determined etiology (133.2 ± 26.1 mmHg, p<0.01) than cardioembolic (150.9 ± 25.5 mmHg), large artery disease (157.1 ± 26.1 mmHg) and cryptogenic stroke (157.7 ± 22.9 mmHg). Median infarct volume was similar across categories of stroke etiology (large artery disease (16.3 (60.3) ml), cardioembolic (19.9 (76.2) ml), other determined etiology (23.9 (33.6) ml), and cryptogenic stroke (11.5 (35.9) ml), p=0.12). There was no correlation between mean prehospital SBP and mean infarct volume (r =-0.06, p=0.33). NIHSS score was correlated with mean infarct volume (r=0.6, p<0.001), but not mean prehospital SBP (r=-0.07, p=0.24).

Conclusion:
These data provide no evidence to suggest that lower prehospital BP is associated with larger infarct volumes in patients with non-lacunar ischemic stroke. The effect of BP reduction on infarct volumes should be assessed as part of randomized trials.
Abstract TP77: Race/Ethnic Disparity Trends in tPA Administration in the United States
Authors: Lin Michelle P , Cen Steven , Towfighi Amytis , Kim-Tenser May , Mack William , Sanossian Nerses
Published: July 2021

Introduction:
Prior studies have shown racial disparities in tPA use for acute ischemic stroke. With the implementation of nationwide quality improvement measures, we sought to describe the temporal change in racial disparity in tPA administration.

Hypothesis:
Disparity in tPA administration improved across all racial groups in the past decade

Methods:
Data were obtained from all US states that contributed to the Nationwide Inpatient Sample. All patients (N=5,932,175) admitted to hospitals between 2000 and 2010 with a discharge diagnosis of ischemic stroke (ICD9 codes) were included. Primary analysis was the proportion of patients who received tPA administration stratified by race (white, black, Hispanic, Asian) temporally. Survey-weighted Poisson regression was used to estimate the rate ratio and compare the trend for yearly change between race categories.

Results:
Of the patients with ischemic stroke, 55.4% were white, black 11.89%, Hispanic 5.32%, Asian 1.89%, others 1.77%, missing race 23.31%. tPA administration rate increased from 2000 to 2010 regardless of race. In 2000, tPA administration rate was 0.96%, 0.40%, 0.73%, 0.59% in white, black, Hispanic, Asian, respectively. In 2010, tPA administration rate was 4.0%, 2.14%, 2.09%, 2.13% respectively. The relative change was the greatest in black with rate ratio of 6.7 (5.95-7.54), compared to other racial groups, Asian 5.36 (4.23-6.78), Hispanic 3.93 (3.42-4.51), and white 3.88 (3.74-4.03).

Conclusions:
Over the last decade, the rate of tPA administration for acute ischemic stroke in the United States have increased for every racial group. There is a lasting but improved disparity in tPA administration in non-white race. Targeted interventions designed to increase treatment and close disparity gap focusing on culturally tailored education and communications to address barriers need to be further explored.
Abstract TP8: A Pilot Study of Selective Brain Cooling by Intra-arterial Infusion of Cold Saline in Acute Ischemic Stroke
Authors: Chen Jian , zhang Hongqi , jiao Liqun , liu Liqiang , Geng Xiaokun , Ding Yuchuan , Ji Xunming
Published: July 2021

Background and purpose:
The neuroprotection of hypothermia in acute ischemic stroke has been proved by many animal experiments. However, the whole body cooling needs relatively longer time to reach target temperature and has many adverse effects. In this trial, we focused on the feasibility and safety of selective brain cooling by intra-arterial infusion of cold saline in patients with acute ischemic stroke during endovascular revascularization procedure.

Methods:
Patients who suffered from large proximal vessel occlusions within 8 hours after symptoms onset were enrolled. All patients received intra-arterial recanalization combined with infusion of isotonic saline (4°C) into ischemic territory through angiographic catheter. Vital signs, physiological parameters, adverse effects and complications were analyzed to evaluate feasibility and safety. Modified Rankin Scale (mRS) and mortality at 3 months were analyzed to evaluate clinical outcome.

Results:
26 patients with a mean age of 58.4±9.56 years and median NIHSS score of 18 (14-20) were enrolled. The median time from symptoms onset to groin puncture was 383 (195-432) minutes. physiologic parameters were relatively stable before, during, and after revascularization procedures. The temperature of ischemic cerebral tissue was dropped at least 2°C theoretically during infusion of the cold solution, and rectal temperature was mildly dropped (maximum 0.3°C), but soon returned to normal after infusion. Complications in these patients included pneumonia (n=10), mild vascular spasm (n=4), melena (n=2), deep vein thrombosis (n=1), coagulation disorder (n=2). No intracranial hemorrhage, shivering, groin hematom, acute congestive heart failure, renal inadequacy, platelet count<100 000/nL and arrhythmia were observed. At 3 months, 15 patients had good outcome (mRS, 0-2) and 11 patients with poor outcome (mRS, 3-6).

Conclusions:
Selective brain cooling by intra-arterial infusion of cold saline combined with endovascular recanalization therapy in acute ischemic stroke is feasible and safe.
Abstract TP82: High Rate of Recanalization and Attenuated Poor Outcome After Intravenous Thrombolysis in “Top-of-the-basilar” Syndrome
Authors: Yan Shenqiang , Zhang Xiaocheng , Han Quan , Lou Min
Published: July 2021

Objective:
The safety and efficacy of intravenous thrombolysis (IVT) in patients with “top-of-the-basilar” syndrome (TOBS) was not systematically investigated. We thus aim to evaluate the rate of recanalization, hemorrhagic transformation and long-term prognosis after IVT in TOBS in our consecutively collected thrombolytic patients.

Methods:
We retrospectively examined clinical and imaging data from consecutive acute ischemic stroke patients with basilar artery occlusion (BAO) who underwent multimodal CT or MRI before and 24 hours after IVT at our center. The presence of Hyperdense artery sign (HAS) on noncontrast CT or Susceptibility vessel sign (SVS) on susceptibility-weighted imaging were recorded. Recanalization, hemorrhagic transformation (HT), and clinical outcome were assessed by Arterial Occlusive Lesion (AOL) scale, ECASS II definition and modified Rankin Scale (mRS), respectively.

Results:
Among all 43 BAO patients with pre- and post-treatment angiongraphy, 24 (55.8%) were considered as TOBS based on either CTA (n = 18) or TOF-MRA (n = 6) before IVT. Follow-up imaging revealed recanalization (AOL ≥ 2) in 19 (79.2%) and HT in 6 (25%) of TOBS patients. This recanalization rate of TOBS was much higher than other LAO (56.2% for M1, 68.0% for M2, 12.8% for internal carotid artery, 50.0% for anterior cerebral artery, 58.3% for posterior cerebral artery, and 21.1% for other type of BAO). Cardioembolic stroke were considered in 18 (75%) of TOBS. The presence of HAS or SVS in TOBS with recanalization was higher than those without (89.5% verse 40%, p=0.042). The rate of poor clinical outcome (mRS ≥ 3) was lower in patients with recanalization than those without recanalization (36.8% verse 100%, p=0.037). 3-month mortality were also lower in patients with recanalization (15.8% verse 80.0%, p=0.014).

Conclusions:
Most (about 80%) of TOBS patients can achieve recanalization after IVT, leading to a dramatic recovery in Chinese population. The presence of HAS or SVS of basilar artery might indicate high rate of recanalization.
Abstract TP93: Early Morphological Changes in Cerebral Arteries of Cerebral Aneurysm Rupture Model Rats
Authors: Maekawa Hidetsugu , Miyamoto Takeshi , Kitazato Keiko T , Yagi Kenji , Tada Yoshiteru , Shimada Kenji , Satomi Junichiro , Nagahiro Shinji
Published: July 2021

Introduction:
To study the pathomechanisms of cerebral aneurysms, we developed a rat model of cerebral aneurysm rupture. In order, the ruptured aneurysms were located at the P1 segment of the left posterior cerebral artery, on the anterior cerebral artery (ACA), the right internal carotid artery (ICA), the right middle cerebral artery (MCA), and the anterior communicating artery (AcomA). We investigated the early morphological changes in these arteries that preceded aneurysm formation.

Methods:
We subjected 10-week-old Sprague-Dawley rats to bilateral ovariectomy and modified carotid artery ligation. They were fed a high salt diet. Two weeks later, the bilateral posterior renal arteries were ligated. Vascular corrosion casts were created 2 weeks after renal artery ligation (n=11) and the morphological features were compared on casts from these- and sham rats (n=3) using a scanning electron microscope.

Results:
The diameter of the left- was larger than of the right P1 in all rats with hypertension and estrogen deficiency. Endothelial changes were predominantly seen in the AcomA and the left P1. In 5 rats we observed small protrusions without loss of endothelial imprints suggesting local loss of internal elastic lamina in the left P1 where ruptured aneurysms were frequently formed. No aneurysms formed at the right ACA-olfactory artery (OA) bifurcation within 2 weeks after aneurysm induction. None of these changes were found in the controls. As ACA-OA aneurysms were frequently seen at 3 months but never ruptured, the pathophysiology of such, and of aneurysms formed at other sites may be different.

Conclusion:
We first demonstrate the initial morphological changes that occurred as early as two weeks after aneurysm induction in rats. Early intervention for hypertension and endothelial damage may be beneficial in the management of cerebral aneurysms.
Abstract WMP10: Validation of the Pittsburgh Response to Endovascular Therapy (PRE) Score in IMS3
Authors: Rangaraju Srikant , Haussen Diogo , Nogueira Raul , Nahab Fadi , Frankel Michael , Jovin Tudor
Published: July 2021

Background:
The Pittsburgh Response to Endovascular therapy (PRE) score incorporates patient’s age, initial NIHSS and pre-treatment CT ASPECTS to predict good outcome in anterior circulation large vessel occlusion (LVO) patients. Further validation of this tool is needed before clinical applicability.

Objective:
To externally validate the PRE score in a randomized trial cohort of anterior circulation LVO patients.

Methods:
Patients in IMS3 who had LVO involving the intracranial internal carotid artery (ICA), M1 or M2 middle cerebral artery (MCA) confirmed either by CT or conventional angiography and had a documented pre-randomization CT ASPECTS, baseline NIHSS and 3-month mRS were included. The PRE score was calculated as follows: Age (years)+ 2xNIHSS - 10xASPECTS. The predictive power of the PRE score for good outcome (3-month mRS 0-2) was compared to THRIVE, SPAN and HIAT-2 scores. Rate of achieving mRS 0-2 was compared across previously published PRE score risk categories.

Results:
407 patients in IMS3 (Endovascular arm: 319 Control arm: 88) had ICA, M1 or M2 occlusions. The cohort had mean age of 66±12 years, median NIHSS 18 [IQR 14-21], median ASPECTS 8 [IQR 6-9] and 38.2% achieved good outcome (mRS 0-2). Age (p<0.001), NIHSS (p<0.001) and ASPECTS (p<0.001) were independent predictors of good outcome. PRE score had good predictive power for mRS 0-2 (AUC=0.73) and Barthel Index≥95 (AUC=0.71) regardless of the treatment arm (AUC=0.72 in both) or reperfusion status. The predictive power for good outcome was similar to HIAT2 (p=0.9) and THRIVE (p=0.10) and slightly superior to SPAN (p=0.06) (Fig 1A). In the endovascular arm, successful reperfusion predicted good outcome (OR 3.1 p<0.001) independently of the PRE score. Rates of good outcome in PRE score risk groups were comparable to the original PRE score derivation cohort (Fig 1B).

Conclusions:
Our results confirm the validity of the PRE score as a prognostic tool in anterior circulation LVO stroke patients.
Abstract WMP102: Infantile Spasms After Early Pediatric Arterial Ischemic Stroke.
Authors: Mineyko Aleksandra , Scantlebury Morris , Kirton Adam
Published: July 2021

Introduction:
Symptomatic infantile spasms (SIS) constitute a debilitating epileptic encephalopathy due to an identifiable lesion in the developing brain. Perinatal and infantile arterial ischemic stroke (AIS) result in a large spectrum of developmental outcomes. Risk factors for worse outcome are not well understood, with epilepsy diagnosis being a poor prognostic factor. As a focal injury in an otherwise healthy brain, early stroke provides unique insight into the developmental effects of epileptic encephalopathy.

Hypothesis:
SIS are a rare complication of AIS in infancy/early childhood. Additional neurological comorbidities are seen in stroke patients with SIS.

Methods:
A population-based cohort of pediatric stroke (Calgary Pediatric Stroke Program) was screened. Inclusion criteria were: (1) MRI-confirmed AIS (2) age at stroke <2 years (3) EEG with hypsarrhythmia, and (4) clinical diagnosis of infantile spasms. Pediatric Stroke Outcome Measure (PSOM) was used to determine neurological outcome at follow up. Poor outcomes included total PSOM >2 and non-motor outcomes >1.

Results:
One hundred and sixty-three children with AIS at <2 years of age were screened. EEGs were available for 92 (56%). Five (3%) of all patients had SIS (3 symptomatic neonatal, 1 presumed perinatal, 1 childhood AIS). Four patients (80%) were male. Strokes were unilateral and involving MCA (4) and PCA (1) territories. Median age at diagnosis was 7 months (range 2-22). Four responded to either vigabatrin and/or ACTH/steroids. One was refractory to several treatments. Compared to 28/158 (18%) in the non-SIS group, 4/5 with SIS (80%) had comorbid neurological diagnoses including genetic syndromes (2), premature brain injury (1), or hypoxic ischemic encephalopathy (1). At a median follow-up of 29 months (range 6-56), all but one patient had poor neurological outcome. One patient with good outcome had no comorbidities. One patient died of causes unrelated to stroke.

Conclusions:
Early AIS can be complicated by infantile spasms but usually only in the context of additional neurological comrobidity. Neurological outcomes are poor but discerning the contribution of the epileptic encephlapathy is challenging as in other IS populations.
Abstract WMP103: Epilepsy is Associated With Poorer Neurologic Outcome After Pediatric Arterial Ischemic Stroke
Authors: Fox Christine K , Jordan Lori C , Mackay Mark T , deVeber Gabrielle ,   Seizures in Pediatric Stroke Investigators
Published: July 2021

Introduction:
Post-stroke epilepsy is common in children, but the relationship of childhood epilepsy with stroke outcome is poorly understood.

Hypothesis:
Children with epilepsy after arterial ischemic stroke have worse outcomes than those without epilepsy.

Methods:
We prospectively enrolled children (birth-18 years) with arterial ischemic stroke and identified remote seizures (occurring ≥ 7 days post-stroke). At one-year, patients with active epilepsy (≥ 1 remote seizure + maintenance anti-convulsant) were identified and Pediatric Stroke Outcome Measure (PSOM) was scored. Total PSOM scores range from 0-10; higher values reflect more severe neurologic deficits. Ordinal logistic regression was used to evaluate the relationship between clinical factors and PSOM scores. PSOM scores were categorized 0-1, 1.5-3, 3.5-6, 6.5-10 to depict stratified distribution.

Results:
Among 94 children (54% male; 20% Hispanic; 25% neonatal strokes; median age for childhood strokes 6.1 years, IQR 1.3-12), 12 had ≥ 1 remote seizure during the first year post-stroke. At one-year follow-up, 19 children were taking a maintenance anti-convulsant and 10 children had active epilepsy. Median PSOM score at one-year for the overall cohort was 0.5 (IQR 0-1.5). Median PSOM score among children with active epilepsy was 3.3 (IQR 0.5-6). Figure demonstrates distribution of categorized PSOM scores stratified by the presence of active epilepsy. On univariable regression analyses, older age (OR 1.1, 95% CI 1.0-1.1, P=0.02), maintenance anti-convulsant at one-year (OR 2.7, 95% CI 1.0-7.0, P=0.04) and active epilepsy (OR 6.3, 95% CI 1.7-25, P=0.007) were associated with higher total PSOM scores. After multivariable adjustment for age and maintenance anti-convulsant, active epilepsy remained associated with higher total PSOM score (OR 7.8, 95% CI 1.3-46, P=0.02).

Conclusions:
Active epilepsy one-year after pediatric arterial ischemic stroke is associated with poorer neurologic outcome.
Abstract WMP106: Reversal of Tonic Inhibition Contributes to Recovery of Synaptic Function After Transient Focal Cerebral Ischemia
Authors: Orfila James E , Dietz Robert M , Grewal Himmat , Shimizu Takeru , Strnad Frank F , Moreno Myriam , Rogers Krista M , Traystman Richard J , Herson Paco S
Published: July 2021

Introduction:
Ischemic stroke is the fourth leading cause of death in the United States and is increasingly being recognized as a disease that occurs in people of all ages, not just the elderly. Studies suggest that the immature developing brain may have a greater degree of plasticity compared to the adult, thereby enhancing functional recovery to a greater extent during development.

Hypothesis:
Pediatric mice exhibit greater recovery from hippocampal synaptic function following experimental stroke than adults.

Methods:
Extracellular field recordings of CA1 neurons were performed in acute hippocampal slices prepared at, 7 or 30 days after recovery from middle cerebral artery occlusion (MCAO). A behavioral fear conditioning paradigm was done to evaluate contextual memory in both pediatric and adult mice 30 days after MCAO. α5 GABAA receptors and GABA transporter expression was evaluated by western blot analysis.

Results:
In adult mice following MCAO, hippocampal long-term potentiation (LTP), defined as an increase in synaptic strength, remained impaired for at least 30 days in the ipsilateral and contralateral, non-injured hemisphere. However, in pediatric mice following MCAO, LTP was only impaired in the ipsilateral side 7 days after MCAO and showed full recovery of synaptic function at 30 days. Behavioral data confirmed these data, showing that only adult mice displayed memory deficits 30 days after MCAO. L655,708 (100nM), an inverse agonist selective for α5 GABAA receptors, rescued LTP in acute slices in both pediatric and adult mice at all-time points tested. Western blot analysis failed to identify any changes in α5 GABAA receptors or GABA transporter (GAT1 or GAT3) levels after MCAO.

Conclusion:
The present study demonstrates that transient focal ischemia causes functional impairment in the hippocampus and that recovery of behavioral and synaptic function is more robust in the young brain. In addition, inhibition of tonic GABA activity rescues synaptic function, indicating that targeting of excessive GABA activity may provide a therapeutic approach to improve cognitive recovery after stroke.
Abstract WMP109: Activation of the Brain Renin-Angiotensin System (RAS) Causes Selective Cerebrovascular Dysfunction
Authors: De Silva Travice M , Grobe Justin , Faraci Frank M
Published: July 2021

Hypertension is a leading risk factor for cerebrovascular disease. Although many changes during hypertension may be mediated by the RAS, most hypertensive patients have normal or reduced levels of circulating renin, suggesting that local tissue RAS play a key role. Surprisingly, little is known regarding the impact of the brain RAS on the cerebral vasculature. We tested the hypothesis that activation of the central RAS using deoxycorticosterone (DOCA)-salt (which simultaneously suppresses the peripheral RAS) alters vascular function. Male C57Bl/6 mice treated with DOCA were given both tap water and water with 0.9% salt for 3 weeks, followed by measurements of vessel reactivity. Mean arterial pressure was elevated modestly after DOCA-salt (79±2 vs 95±3 mmHg; P<0.01). In DOCA-salt treated mice, endothelium-dependent dilation of isolated middle cerebral arteries was almost abolished compared to shams, whereas dilation in mesenteric arteries was normal. This striking effect in brain extended to small parenchymal arterioles. Endothelium-independent vasodilation was similar in all groups. Analysis of mRNA revealed that expression of renal renin was markedly reduced by DOCA-salt while expression of RAS components (eg, AGT, ACE) were increased in both brain and cerebral arteries. In NZ44 reporter mice that express GFP driven by the angiotensin II type 1A receptor (AT1AR) promoter, DOCA-salt significantly increased AT1R-GFP protein expression in cerebral arteries. In cerebral arterioles in vivo, local inhibition of AT1R, mineralocorticoid receptors (MR), or Rho kinase (including ROCK2) reversed endothelial dysfunction in DOCA-salt treated mice. These findings suggest for the first time that activation of the brain and the cerebrovascular RAS profoundly, but selectively, impairs vascular function in brain. Our findings identify AT1R, MR and Rho kinase as key contributors to vascular dysfunction in brain in a clinically relevant model of hypertension.
Abstract WMP113: Genetic Influences on Early Neurological Instability After Acute Ischemic Stroke
Authors: Ibanez Laura , Heitsch Laura , Carrera Caty , Fernandez Israel , Montaner Joan , Cruchaga Carlos , Lee Jin-Moo
Published: July 2021

Following acute ischemic stroke (AIS) onset, neurological deficits can be highly unstable. Early neurological change within the first 24 hours, defined here as ΔNIHSS24h (NIHSSbaseline-NIHSS24hours), substantially influences long-term outcome. While several mechanisms, such as hemorrhagic transformation and recanalization, may impact ΔNIHSS24h, little is known about genetic influences. Genetic variants associated with ΔNIHSS24h may identify genes involved in mechanisms of early neurological outcome after AIS. AIS patients were prospectively enrolled between 2008-2014 at two sites (St Louis and BCN; Table 1). NIHSS scores were obtained within 6 hours and again at 24 hours after stroke onset. Genome-wide genotyping was generated for rare and common variants, imputing up to 6 million single nucleotide polymorphisms (SNPs) for all subjects (N=891). ΔNIHSS24h was used as a quantitative trait to measure early improvement/deterioration. Genome-wide complex trait analysis (GCTA) was performed. An association model was done, using NIHSSbaseline, age, gender, glucose, PCA1 and PCA2 as covariates. All samples were analyzed together and then separately by ethnicity (Spanish, European-American (EA), and African-American (AA)). GCTA indicates that common variants account for 23-28% of ΔNIHSS24h variability. VAV3 rs72689643 (p=8.21x10-8) was associated with ΔNIHSS24h in the whole cohort analysis (Figure 1). Three additional suggestive SNPs were found: 2 intergenic SNPs (rs139950151 and rs73706194 - both p=6.1x10-7) in high LD and SNP rs10431426 (p=1.71x10-7) located in an intron. When analyzed by ethnicity, these findings did not reach GWAs significance, likely due to lack of power. Early neurological outcome after AIS is strongly influenced by genetics. Vav3 shows association with ΔNIHSS24h in the whole cohort while several other SNPs are suggestive. Rare variant analysis is underway, and we will also have an additional 800 genotypes analyzed by ISC.
Abstract WMP23: Regional Assessment of Multi-phase CTA and CT Perfusion are Equivalent in Predicting Tissue Fate in Ischemic Stroke
Authors: d'Esterre Christopher D , Trivedi Anurag , Zhang Yukun , Patil Shivanand , Pordeli Pooneh , Qazi Emmad , Ahn Seong Hwan , Najm Mohamed , Fainardi Enrico , Rubiera Marta , Hill Michael D , Demchuk Andrew M , Goyal Mayank , Sajobi Tolulope , Menon Bijoy K
Published: July 2021

Introduction:
The use of CT Perfusion (CTP) in acute ischemic stroke (AIS) to determine patients with large ischemic core is still hampered by slow processing time, among other technical/standardization issues. Multi-phase CTA (mCTA) may be quicker and more practical in this regard. We sought to determine i) the performance of mCTA and CTP to predict regional infarction and ii) which mCTA construct(s) corresponds to which CTP parameter .

Methods:
mCTA and CTP was performed less than 12hrs from ictus in 77 patients with MCA-M1 occlusions. Regional analysis was performed within M2-M6 ASPECTS-regions. mCTA: regional pial vessels were assessed according to three constructs: i) Delay in maximal pial vessel enhancement compared to contralateral hemisphere; ii) Washout of contrast within pial vessels; iii) Extent of maximal pial vessel enhancement compared to contralateral hemisphere (Figure 1). CTP-CBF, CBV, MTT, IRF-T0, and Tmax values were determined. 24-hour MR-DWI or NCCT was used for final infarction.

Results:
There was a negligible difference in the predictive accuracy of mCTA and CTP in discriminating infarction (i.e., 84.59% and 83.04%, respectively). mCTA-Extent had the largest discriminatory power, while CTP-Tmax had the largest discriminatory power.

Conclusion:
Herein we show that mCTA assessments, even within small brain regions can help determine tissue fate when adjusted for recanalization, and is as good as CTP. mCTA may be a more practical modality to obtain similar prognostic information for radiological and clinical outcomes in AIS, informing acute treatment and tertiary centre triaging.
Abstract WMP24: Quantitative Relaxometry Quantifies Brain Edema After Ischemic Stroke
Authors: Battey Thomas W , Zhou Iris Y , Ostwaldt Ann-Christin U , Igarashi Takahiro , Sun Philip Z , Kimberly W. Taylor
Published: July 2021

Introduction:
Brain edema is an adverse complication of ischemic stroke, and is associated with substantial morbidity and mortality. We investigated whether relaxometry parameters of MRI are a reliable measure of brain edema in an animal model.

Hypothesis:
We hypothesize that quantitative relaxometry parameters of MRI in a rat model of stroke tightly correlate with brain edema.

Methods:
We permanently occluded the middle cerebral artery of 18 rats using the filament occlusion method. Fifteen surviving animals were imaged at 48 hours with a Bruker 4.7 T MRI scanner with Diffusion-weighted imaging (DWI), T1 and T2 maps, and proton-density weighted (PDW) imaging. Hemispheric and lesional volumes were generated on DWI. For quantitative T1, quantitative T2 and PDW images, signal intensity values relative to the contralateral hemisphere were determined. The percent water content in the rat brain was measured using the wet-dry method. Additional volumetric measurements of swelling were calculated based on hemisphere volumes determined on MRI. Correlation testing and logistic regression was performed to assess the relationship between imaging measures and swelling.

Results:
The mean lesion volume was 352 mm3. Brain water content and swelling volume were closely associated (r=0.80, p<0.001). PDW, T1 and T2 ratios highly correlated with brain water content (r=0.91, p<0.0001, r=0.94, p<0.0001 and r=0.97, p<0.0001, respectively). Ratios for PDW, T1 and T2 were also associated with swelling volume (r=0.67, p<0.0063, r=0.73, p<0.0022, and r=0.74, p<0.0017).

Conclusion:
Signal intensity ratios derived from PDW as well as quantitative T1 and T2 MRI can be leveraged to quantify brain water content and brain edema. These measures are useful markers for edema quantification that can be applied to any condition that leads to brain edema in both animal models and human patients.
Abstract WMP26: Missense Mutation in COL22A1 is Associated With Intracranial Aneurysms
Authors: Ton Quynh , Leino Daniel , Broderick Joseph , Foroud Tatiana , Sumanas Saulius
Published: July 2021

Background:
Both environmental and genetic factors have been linked to the formation of intracranial aneurysms (IAs), but animal models to explore mechanisms underlying genetic risk factors of IAs in humans are lacking.

Methods:
To identify additional genes responsible for IA development, whole exome sequencing of the patients from seven selected families was performed. One of the identified variants found in all five affected members of one family was a missense mutation in the highly conserved triple-helix region of the collagen
COL22A1
isoform, the function of which has not been previously known. This mutant variant was examined in zebrafish embryonic and adult models.

Results:
We demonstrated that
COL22A1
is expressed in cranial tissues as well as in the cells between myotomes in the trunk and tail region of the zebrafish embryos. Early global overexpression of the human mutant but not human wild-type
COL22A1
in the zebrafish embryos interfered with epiboly movements during gastrulation suggesting that the mutation has a deleterious dominant effect. We then used TALEN-engineered nucleases to generate a loss-of-function mutant in zebrafish
col22a1
. The homozygous null mutants were viable as adults but exhibited increased abnormal blood accumulations in the eyes and cranial regions, suggestive of hemorrhages. We further notice abnormal lesions existed in the trunks of these adults caused by rupture of blood vessels. A subset of the mutant adults shows cardiac dilation and a phenotype consistent with dilated cardiomyopathy. We further demonstrated that the homozygous embryos show increased sensitivity to cardiovascular stress, which results in a greater percentage of embryos with intracranial hemorrhages. The mutant embryos also exhibited increased vascular permeability as demonstrated by nano-particle injection into the circulation of 4-day post fertilization embryos.

Conclusions:
Our results suggest that the function of COL22A1 is important in maintaining vascular integrity and that mutations in COL22A1 are a potential one genetic cause for intracranial aneurysms in humans.
Abstract WMP28: Association Between Diffusion Positive Lesion and Antiplatelet Drug Resistance After Coiling for Unruptured Intracranial Aneurysm
Authors: Jo Kyung Il , Yeon Je Young , Kim Jong Soo , Kim Jong Soo , Hong Seung Chyul
Published: July 2021

Background:
The purpose of this study was to verify the association between immediate post-procedural thromboembolic infarction and antiplatelet drug resistance after endovascular coil embolization for unruptured intracranial aneurysm.

Method:
This study included 338 aneurysm cases between October 2012 and March 2015. All patients received post-procedural MRI within 48 hours after endovascular coil embolization. Antiplatelet drug resistance was checked a day before the procedure using the VerifyNow system. Abnormal antiplatelet response was defined as more than 550 aspirin response units (ARU) and more than 240 P2Y12 receptor reaction units (PRU). Also, we explored the optimal cutoff values of ARU and PRU. The primary outcome was radiologic infarction based on post-procedural MRI.

Results:
Among 338 unruptured intracranial aneurysms, 32 (9.5%) and 105 (31.1%) had abnormal ARU and PRU values, respectively. Radiologic infarction was associated with old age (≥65, adjusted odds ratio (OR)1.777, 95% confidence interval (CI) 1.080-2.925) only with defined abnormal antiplatelet response (ARU≥550, PRU≥240). PRU values in the top 10
th
percentile (>294) were associated with radiologic infarction (
p
=0.003, OR 4.8, 95% CI 1.708-13.492). Using this cutoff value, age (OR 2.287, 95% CI 1.282-4.079), PRU (>294, OR 3.431 95% CI 1.528-7.706), and hyperlipidemia (OR 2.046 95% CI 1.041-4.020) were associated with radiologic infarction in multivariate analysis.

Conclusions:
Radiologic infarction after coiling for unruptured aneurysm was closely associated with age. Only very high PRU values (>294) predicted post-procedural infarction. Further controlled studies are needed to determine precise cutoff values which could provide information regarding the optimal antiplatelet regimen for aneurysm coiling.
Abstract WMP41: Characterization of MicroRNAs and Their Target Proteins in Distal Axons of Cortical Neurons
Authors: Li Chao , Zhang Yi , Levin Albert M , Chopp Michael , Zhang Zheng Gang
Published: July 2021

Introduction:
Axonal growth is essential for the establishment of a functional neuronal network. Molecular information of axon is limited. MicroRNAs (miRNAs) regulate post-transcriptional gene expression. We hypothesized that axonal miRNAs are locally relevant to their target genes.

Methods:
Proteins and RNAs were extracted from distal axons of cortical neurons cultured in a microfluidic device. A mass spectrometer and miRNA arrays were used to measure proteins and miRNAs, respectively. Ingenuity Pathway Analysis (IPA) and Database for Annotation, Visualization and Integrated Discovery (DAVID) bioinformatic tools were used to make in silico predictions of functionally relevant miRNA target genes.

Results:
Proteomic showed that distal axons contained 883 proteins. Bioinformatic analysis showed the presence of 94 proteins that regulate axonal growth. To identify relevant miRNAs to these 94 proteins, miRNAs with 8mer sites that exactly match target genes were considered, based on the fact that 8mer sites efficaciously affect miRNA-target interactions. Of the 94 genes, we found that there were 56 candidate genes that can be targeted by 62 miRNAs enriched in axons. Among them, we validated 13 proteins and 11 miRNAs, respectively, by means of Western blot and RT-PCR. To examine target genes, we treated axons with chondroitin sulfate proteoglycans (CSPGs) that inhibit axonal growth and examined alterations of these proteins and miRNAs in the distal axons. We found that elevation of miR-203a, -133b, -29abc and -92ab were associated with reduced AKT, MTOR, PI3Kp85, DPYSL2, MAP1B, PPP2CA and DCX proteins, whereas decreased miR-15b, -26b, -34b, -376b, -128, -381 and -195 were accompanied by increased proteins of EZR, KIF5A, RTN4, GSK3B, and ROCK2. Bioinformatic analysis revealed that these miRNAs and proteins are highly related to the axonal growth network. These data suggest that miRNAs altered by CSPGs functionally target these genes for mediating the inhibitory effect of CSPGs on axonal growth.

Conclusions:
Our bioinformatic analyses of miRNAs and proteins in the distal axon identifies an interconnected group of miRNAs and their target genes that regulate axonal growth, which provides new insight into the molecular mechanisms underlying axonal growth.
Abstract WMP44: Mir-145 Mediates Bone-marrow-stromal Cell Derived From Type-one Diabetes (t1dm) Rats Induced Neurorestorative Effects in T1dm Rats
Authors: Cui Chengcheng , Chopp Michael , Ye Xinchun , Zacharek Alex , Ning Ruizhou , Yan Tao , Cui Xu , Yu Peng , Roberts Cynthia , Chen Jieli
Published: July 2021

Objective:
Treatment of stroke with bone-marrow-stromal cells (BMSCs) derived from type-one diabetes (T1DM) rats (DM-BMSCs) improves functional recovery compared to BMSCs derived from normal rats (Nor-BMSCs) and non treatment T1DM rats. In the study, we tested the mechanisms underlying the benefit of the treatment of T1DM stroke with DM-BMSCs.

Methods:
T1DM rats induced by streptozocin in male Wistar rats were subjected to 2h middle cerebral artery occlusion (MCAo) and were treated at 24h after MCAo via tail vein with: 1) vehicle control; 2) DM-BMSCs; 3) DM-BMSCs with miR-145 overexpression (miR-145+/+DM-BMSCs)(5x10^6) (n=8/group). A battery of functional tests, vascular,white matter (WM) measurements, and cell culture experiments were performed.

Results:
In vitro, DM-BMSCs exhibited reduced level of miR-145, and increased survival rate compared to Nor-BMSCs. miR-145+/+DM-BMSCs significantly decreased DM-BMSCs survival. DM-BMSCs media increased capillary tube formation and axonal outgrowth in cultured primary cortical neurons (PCNs) compared to Nor-BMSCs media. While miR-145+/+DM-BMSCs exhibited reverse effects compared to DM-BMSCs media. In vivo, DM-BMSCs improved functional outcome, vascular and WM remodeling in the ischemic border zone (IBZ) compared to T1DM-MCAo rats. However, miR-145+/+DM-BMSCs significantly attenuated DM-BMSCs induced beneficial effects. To further test the underlying mechanism of miR-145 mediated DM-BMSCs induced therapeutic effects in T1DM stroke rats, miR-145 target genes adenosine triphosphate-binding cassette transporter 1 (ABCA1) and insulin-like growth factor 1 receptor (IGFR-1) were measured in IBZ. ABCA1 and IGFR1 have neurorestorative effects. Reduction of IGF1 contributes ABCA1 deficiency induced damage in ischemic brain. We found that DM-BMSCs significantly decreased miR-145, increased ABCA1 and IGFR-1 expression in IBZ compared to Nor-BMSCs. While miR-145+/+DM-BMSCs significantly decreased ABCA1 and IGFR-1 expression in IBZ.

Conclusion:
DM-BMSCs exhibit decreased miR-145 expression and increase miR-145 target gene ABCA1 and IGFR-1 expression in ischemic brain. The miR-145/ABCA1/IGFR-1 pathway may contribute to DM-BMSCs induced neurorestorative effects in T1DM stroke.