bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P741: Elemental Calcium Influx Through Endothelial N-Methyl-D-Aspartate Receptors is Impaired by Acute Amyloid-

β
(1-40)

in Cerebral Arteries
Authors: Peters Emily C , Kath Allison M , Gee Michael T , Pires Paulo W
Published: March 2021

Introduction:
Cerebral amyloid angiopathy (CAA), the accumulation of amyloid-

β
(1-40)

(A
β
) around cerebral arteries, impairs endothelial function. Endothelium-dependent dilation is a consequence of transient increases in intracellular [Ca
2+
] in endothelial cells (EC). The Ca
2+
permeable N-methyl-D-aspartate receptor (NMDAR) mediates endothelium-dependent dilation, although if these effects are dependent on Ca
2+
influx and transients, or if they are impaired by A
β
, remains undetermined.

Hypothesis:
A
β
inhibits endothelial NMDAR-mediated Ca
2+
influx and transients in murine pial arteries.

Methods:
We performed Ca
2+
time-lapse imaging of
en face
pial arteries from
cdh5-GCaMP8
mice to quantify EC Ca
2+
events induced by NMDAR activation. Data are means ± SEM.

Results:
Elemental Ca
2+
entry through NMDAR, hereon called
NMDAR sparklets
, was assessed in arteries incubated with EGTA-AM and cyclopiazonic acid (CPA) to inhibit intracellular Ca
2+
transients. NMDA (10 μM) induced an increase in
NMDAR sparklets
frequency when compared to vehicle, an effect inhibited by the NMDAR antagonist D-APV (in Hz: 0.12±0.01 vs 0.44±0.05 vs 0.21±0.02, vehicle vs NMDA vs NMDA+D-APV, p<0.05). Further, pial arteries exposed to NMDA without EGTA-AM and CPA showed an increase in the frequency of intracellular Ca
2+
transients, also blocked by D-APV (in Hz: 0.24±0.05 vs 0.53±0.10 vs 0.28±0.05, vehicle vs NMDA vs NMDA+D-APV, p<0.05). We then tested the effects of A
β
on Ca
2+
events in pial artery EC. We observed that 30 minutes exposure to A
β
(5 μM) caused a significant reduction in
NMDAR sparklets
(in Hz: 0.62±0.07 vs 0.22±0.03, NMDA vs NMDA + A
β
, p<0.05) but did not significantly alter intracellular Ca
2+
transients (in Hz: 0.62±0.37 vs 0.27±0.07, NMDA vs NMDA + A
β
). Lastly, we performed pressure myography on pial arteries of wild-type and
5x-FAD
mice, a model of familial Alzheimer’s disease with rapid amyloid accumulation.
5x-FAD
mice displayed impaired vasodilation to NMDA (vasodilation (%): 9.86±0.64 vs 4.22±2.76, wild-type vs
5x-FAD
, p<0.05).

Conclusion:
These preliminary data suggest that A
β
impairs endothelial NMDAR-associated Ca
2+
influx events in cerebral arteries, which can impair blood flow in CAA patients, thus contributing to cognitive impairment.
Abstract P745: Whole Blood MicroRNA and Their Target Messenger RNA Reveal Distinct Transcriptional Changes in Ischemic Stroke Patients With and Without Comorbid Cancer
Authors: Navi Babak B , Sherman Carla P , LeMoss Natalie M , Lansdale Kelsey N , Kamel Hooman , Tagawa Scott T , Saxena Ashish , Ocean Allyson J , Iadecola Costantino , DeAngelis Lisa M , Elkind Mitchell S , Knepp Bodie , Hull Heather , Jickling Glen C , Sharp Frank R , Ander Bradley P , Stamova Boryana
Published: March 2021

Introduction:
One-tenth of patients with stroke have cancer. We previously identified mRNA profiles differentiating patients with stroke and cancer, stroke only, and cancer only. In this study, we investigated mRNA and microRNA (miRNA) transcriptomes to identify potential miRNA regulators that underlie the observed mRNA changes.

Methods:
We prospectively enrolled 4 groups of subjects at 3 centers from 2009-2020. This analysis included 41 subjects with ischemic stroke plus cancer, 42 subjects with ischemic stroke only, 28 subjects with cancer only, and 30 vascular risk factor controls. Stroke-only and cancer-only subjects were matched to stroke-plus-cancer subjects by age, sex, and cancer type. We performed miRNA and mRNA sequencing on blood drawn 72-120 hours after stroke. ANCOVA estimated differential expression of miRNA and mRNA between groups (FDR p<0.05, |fold-change|>1.2). Analyses were adjusted for time from stroke onset, sex, age, vascular risk factors and batch.

Results:
We identified differential expression in 36 miRNA and 264 corresponding mRNA targets between the stroke-plus-cancer and stroke-only groups after accounting for cancer-only expression (Fig 1). Immune and coagulation pathways, including complement, platelet glycoproteins, TGF-β, and mTOR signaling, were overrepresented in stroke-plus-cancer vs stroke-only subjects. T cell, B cell and platelet precursor-specific genes were also overrepresented in stroke-plus-cancer subjects. When compared to other groups, stroke-plus-cancer subjects had 230 unique mRNA encoding for transcriptional regulators, including those involving splicing, epigenetics, and mediator complex genes bridging transcription factors and RNA transcriptional machinery.

Conclusion:
Patients with stroke and cancer had distinct signatures of miRNA and target mRNA compared to stroke patients without cancer, supporting the hypothesis that cancer-related stroke is a unique subgroup of ischemic stroke.
Abstract P746: Sex Differences in Cognitive and Psychological Outcomes of Stroke: Impact of Diabetes
Authors: Wolf Victoria L , Miller Aunay , Chandran Raghavendar , Li Weiguo , Ergul Adviye
Published: March 2021

Diabetes increases risk and severity of post-stroke cognitive impairment (PSCI), a major cause of disability worldwide. While it is known that females suffer more from PSCI, psychological outcomes and underlying reasons are poorly understood. From a preclinical perspective, potential explanations include 1) use of otherwise healthy animals in experimental stroke research without integration of common comorbid diseases like diabetes into the study design, and 2) optimization of most behavioral tests for sensorimotor and cognitive functions using only male animal models. Our
hypothesis
is that post-stroke outcomes are sex and comorbid disease-dependent. To test this, we validated the Novel Object Recognition (NOR), Y-maze, and Passive Avoidance (PAT) behavioral paradigms in Ctrl and Diabetic (DM) male (M) and female (F) rats pre- and post-stroke (S) via 60 min. middle cerebral artery occlusion (MCAO). We tested the PAT paradigm with a multi-trial method where the animals were habituated to the dark/light chambers without foot shock and then trained in 3 trials where they received foot shock upon entering the dark. We then tested retention following MCAO for their memory of foot shock 2 weeks prior. Multitrial results suggested that there was no difference between groups in learning to associate the dark chamber with the shock, so we revised the multitrial method into a single-trial method for ongoing retention tests to compare the impact of stroke on shock memory recall. PAT revealed
(Table 1)
disease- and sex-dependent responses to aversive stimulus. NOR revealed that M-DM-S and F-DM-S rats have decreased exploration time, suggesting that they are unmotivated or depressed. Y-maze indicated that males displayed spatial memory recovery, while females remained impaired. In summary, we have observed numerous sex- and disease-dependent post-stroke outcomes with standard behavioral paradigms, causing us to carefully consider how we evaluate preclinical outcomes.
Abstract P752: Neuroprotection by Remote Ischemic Conditioning in the Setting of Acute Ischemic Stroke: A Preclinical Two-Centre International Study
Authors: Basalay Maryna V , Wiart Marlene , Chauveau Fabien , Dumot Chloe , Leon Christelle , Amaz Camille , Bolbos Radu , Cash Diana , Kim Eugene , Mechtouff Laura , Cho Tae-Hee , Nighoghossian Norbert , Davidson Sean M , Ovize Michel , Yellon Derek M
Published: March 2021

Background and Purpose:
Currently, reperfusion is the only existing treatment strategy for patients with acute ischemic stroke. However, reperfusion may cause further brain damage. One of the feasible therapies targeting reperfusion injury is remote ischemic conditioning (RIC).
The main objective of this study was to test the neuroprotective effects of RIC in a rat model of acute ischemic stroke in a randomized and blinded two-centre MRI study with a priori sample size calculation
.

Methods:
Eighty male Sprague Dawley rats underwent 90-min middle cerebral artery occlusion. Multiparametric MRI was performed per-occlusion to ascertain focal cerebral ischemia (inclusion criteria) and to control interindividual variability in the analysis. RIC was started 10 min before reperfusion, and consisted of 4 cycles of 5-min left hind limb ischemia. The primary endpoint of the study was infarct size measured on T2-weighted MRI at 24h, corrected for edema, and
expressed as percentage of the area-at-risk of infarction
. Secondary endpoints were hemispheric space-modifying edema, infarct growth between per-occlusion and 24h MRI, and neurofunctional outcome measured by neuroscores.

Results:
Two animals died in each group. In total, 47 rats were included in the analysis after applying the pre-defined inclusion criteria (23 in control group and 24 in RIC group). Infarct size was significantly reduced in the RIC group (mean, interquartile range: 19% [8% ; 32%] vs control: 40% [17% ; 59%], p=0.028). This infarct-limiting effect was still statistically significant after adjustment for apparent diffusion coefficient (ADC) lesion size in multivariate analysis. In the subgroup of rats with ADC lesion > 100 mm3, infarct size reduced from 58% [40%; 66%] to 32% [27%; 40%], p=0.004. In line with this result, RIC significantly improved neuroscores (6 [3 ; 8] vs control: 9 [7 ; 11], p=0.032). The other secondary endpoints were not statistically different between groups.

Conclusions:
RIC in the setting of acute stroke in rats is safe, reduces infarct size and improves functional recovery in a two-centre international study using translational imaging endpoints.
Abstract P760: Plasma Kallikrein Contributes to Intracerebral Hemorrhage and Hypertension in Stroke-Prone Spontaneously Hypertensive Rats
Authors: Simao Fabricio , Guan Jian , Clermont Allen , Pham Loc-Duyen , Ustunkaya Tuna , Feener Edward P
Published: March 2021

Introduction:
Hypertension is a leading risk factor for spontaneous intracerebral hemorrhage. Plasma Kallikrein (PKa) has been implicated in contributing to hemorrhage following thrombolytic therapy, however, its role in spontaneous intracerebral hemorrhage is currently not available. This report investigates the role of PKa on hemorrhage and hypertension in stroke-prone spontaneously hypertensive rats (SHRSP).

Methods:
SHRSP were fed with a high salt containing stroke-prone diet to increase blood pressure and induce spontaneous intracerebral hemorrhage. The roles of PKa on blood pressure, intracerebral hemorrhage, and survival in SHRSP were examined in rats receiving a PKa inhibitor (BPCCB) or plasma prekallikrein antisense oligonucleotide (PK ASO) compared with rats receiving control ASO. Effects on PKa on the proteolytic cleavage of atrial natriuretic peptide (ANP) were analyzed by tandem mass spectrometry.

Results:
PKa activity in plasma was increased by 29% in SHRSP on high salt diet compared with control rats. Cleaved kininogen, a substrate for PKa, was 2-fold greater in SHRSP plasma during stroke compared with SHRSP without stroke symptoms. Systemic administration of BPCCB or PK ASO to SHRSP reduced intracerebral hemorrhage (Fig. 1A) and blood pressure (Fig. 1B), and improved neurological function and survival when compared with rats receiving control ASO. Since PKa inhibition was associated with reduced blood pressure in hypertensive rats, we investigated the effects of PKa on the cleavage of ANP. Incubation of PKa with ANP resulted in the generation fragment ANP
5-28
, which displayed reduced effects on blood pressure lowering compared with full length ANP.

Conclusions:
PKa contributes to increased blood pressure in SHRSP, which is associated with intracerebral hemorrhage and reduced survival. PKa-mediated cleavage of ANP reduces its blood pressure lowering effects and thereby may contribute to hypertension-induced intracerebral hemorrhage.
Abstract P764: Single versus Dual Dose of Intra-Arterial Stem Cell Therapy for Stroke
Authors: Thakkar Roshni , Watanabe Mitsuyoshi , Bhattacharya Pallab , Dong Chuanhui , Raval Ami P , Khan Aisha , Hare Joshua M , Yavagal Dileep R
Published: March 2021

Introduction:
Pre-clinical studies have shown great promise in the use of cell-based therapies for stroke. Intra-arterial (IA) delivery directs the cells to the injured brain, is minimally invasive and widely available, making it attractive for clinical translation. Our group and others have shown the safety and efficacy of IA Mesenchymal Stem Cell (MSC) treatment in a rodent stroke model at 24 hours post-reperfusion. The optimal timing of a single dose of IA MSC is unknown. Also, whether an additional dose will lead to greater benefit and the optimal timing of the second dose need to be determined for successful translation of IA MSC to clinic. The
objective
of this study is to determine if dual dose IA-MSC treatment is superior to single dose and find the optimal timing for the second dose.

Methods:
We used a reversible middle cerebral artery occlusion (rMCAO) model for stroke in rats. IA-MSCs were administered using a PE-10 catheter at 1, 2 and 4 day after stroke as single dose. Based on the results of the first experiment, dual doses were given at 1-4, 1-6 and 1-15 day. Behavioral analysis of rotarod, neurological deficit scoring and stroke volume were determined at 30 days after treatment.

Results:
Single dose IA-MSC at 1day was superior (p=0.02, 0.01, 0.04) to single dose given on day 2 and no benefit was seen when given on day 4. Among the dual dose groups, 1-6 day after stroke showed significant improvement in neurodeficit score and stroke volume (p=0.007, p=0.03). However, the percentage increase in improvement in 1-6day (dual) was much higher than that observed in 1day (single) group (Fig 1). Detailed results will be presented at the meeting.

Conclusion:
The results of our study indicate that 1day after stroke is optimal for single dose of IA-MSC. An additional dose at 6days after stroke enhances the effect of IA-MSC in aiding symptomatic recovery and stroke lesion reduction. In summary, our findings contribute to understanding of the benefit of dual dose of IA MSC for translation to the clinic.
Abstract P765: Therapeutic Approaches to Reduce Post-Stroke Cognitive Impairment
Authors: Basak Jacob M , Orfila James E , Dietz Robert , Burch Amelia , Dingman Andra , Mitchell Danae , Wassermann Benjamin , Quillinan Nidia , Herson Paco S
Published: March 2021

Introduction:
Cognitive impairments and memory loss are common after stroke, with an emerging awareness of a high risk of conversion to post-stroke dementia. It is increasingly clear that in addition to neuronal injury following cerebral ischemia, impaired functional networks contribute to long-term functional deficits. Synaptic plasticity (LTP) is the leading cellular model of learning and memory. Thus, we utilize electrophysiological recordings of hippocampal LTP as an indicator of network health following ischemia in combination with neurobehavioral assessments of memory function.

Hypothesis:
Focal ischemic stroke increases soluble amyloid beta (Aβ) in the hippocampus, causing impaired plasticity and memory function.

Methods:
Extracellular field recordings of CA1 neurons were performed in acute hippocampal slices prepared 30 days after recovery from transient MCAO (45 min) in adult (6-8 week) mice. A behavioral fear conditioning paradigm (CFC) was used to evaluate memory. ELISA assay was used to quantify soluble Aβ42 from the hippocampus. Slices were treated with Aβ42 oligomers with and without our newly developed peptide inhibitor of TRPM2, termed tatM2NX.

Results:
Recordings from brain slices 30 days after MCAO showed near complete loss of LTP; 161±9%, n=6 in sham compared to 115±4%, n=7 30 days after MCAO in the hippocampus. MCAO decreased freezing behavior, indicating lack of memory (65±7% in sham mice (n=6) and 37±7% in MCAO mice, n=7). We observed a 48% increase in Aβ42 in the hippocampus 30 days after MCAo. We observed that addition of Aβ42 oligomers (500 nM) impaired LTP. This impaired LTP was prevented with co-application of the TRPM2 channel inhibitor tatM2NX. Consistent with a role of TRPM2 channels in post-stroke cognitive impairment, MCAO mice treated with tatM2NX (20 mg/kg iv injection 24 hr before testing) on day 29 post MCA demonstrated increasing freezing to 72±5% (n=9).

Conclusion:
Our data implicates increased levels of soluble Aβ42 in the hippocampus following stroke, resulting in activation of TRPM2 channels and impaired synaptic plasticity. Therefore, reducing soluble Aβ42 and/or inhibition of TRPM2 channels at chronic time points following ischemia may represent a novel strategy to improve functional recovery following stroke.
Abstract P768: Vascular Cellular Adhesion Molecule Targeting for the Treatment of Acute Neurovascular Inflammation
Authors: Nong Jia , Marcos-Contreras Oscar Armando , Kiseleva Raisa , Glassman Patrick , Descamps Helene , Thaiss Christoph , Weissman Drew , Brenner Jacob , Muzykantov Vladimir R
Published: March 2021

Targeted drug delivery is an attractive strategy for treatment of life-threatening inflammatory brain pathologies such as ischemic stroke. In these conditions, adhesion molecule expression (e.g. vascular cellular adhesion molecule-1, VCAM) is upregulated on endothelium. Hence, VCAM represents a relevant target for selective drug delivery. We have utilized αVCAM monoclonal antibodies to target therapeutic proteins and nanocarriers (liposomes and lipid nanoparticles, LNPs) to the pathologically-altered vasculature.To assess tissue biodistribution and therapeutic effects of VCAM-targeted agents, we used 2 mouse models: 1) acute inflammation induced by intra-striatal injection of tumor necrosis factor-α (TNF), and 2) ischemic stroke induced by transient middle cerebral artery occlusion (tMCAO). Biodistribution was assayed by measuring radioactivity in blood and organs 30 minutes after injection. Efficacy was determined by tracing radiolabeled albumin extravasation to assess edema.The results showed that VCAM targeting was increased by TNF injection, and that targeting to VCAM enhanced the cerebral accumulation of αVCAM conjugated thrombomodulin (TM) and nanocarriers by orders of magnitude (Fig A). It is noteworthy that αVCAM-TM and free αVCAM antibody had similar levels of brain uptake. Our data also demonstrated the protective effect of αVCAM-liposome loaded with dexamethasone on brain edema (Fig B), indicating the therapeutic potential of VCAM-targeting drug delivery strategies. Further, the results in tMCAO model recapitulated our findings in the TNF model that targeting to VCAM significantly improves delivery to the ischemic brain (Fig C). In summary, we have shown that targeting VCAM permits delivery of a diverse array of therapeutics to the inflamed vasculature in conditions such as ischemic stroke. Future work will focus on evaluating the therapeutic properties of VCAM-targeted drug delivery strategies.
Abstract P769: Remodeling of the Leptomeningeal Collaterals Following Stroke Involves Selective Upregulation of Von Willebrand Factor (VWF)
Authors: WU TING , Stephenson Jessica , Kim Gab Seok , Gireud Monica , Marrelli Sean P
Published: March 2021

Introduction:
The leptomeningeal collaterals (LMCs) are arterial anastomoses that interconnect the distal branches of the major cerebral arteries. They distribute blood flow from adequately to poorly perfused vascular territories when needed. In normal conditions, the LMCs experience little net flow. However, during ischemic stroke, the LMCs are recruited to provide rescue flow to the ischemic territory. During prolonged or permanent stroke, the LMCs can rapidly remodel to provide increased perfusion capacity. Von Willebrand factor (VWF) is a secreted protein expressed in cerebral endothelium and has recently been implicated in angiogenesis. We sought to determine if VWF expression was increased in remodeling LMCs in the post-stroke brain.

Methods:
C57BL6 mice were subjected to permanent distal middle cerebral artery occlusion (pdMCAO). At 3 days after pdMCAO, mice were perfused with fluorescent tomato lectin to label vascular endothelium. The cortical surface was “planed off” by vibratome to provide largely contiguous cortical surface vessel preparations containing distalmost arterioles (DMAs) and the connected LMCs. VWF immunofluorescence intensity was measured in LMCs and the connecting DMAs of hemispheres ipsilateral and contralateral to the stroke. Inner diameter of the LMCs and DMAs were measured with Image J.

Results:
At 3 days post-stroke, LMCs of the stroke hemisphere demonstrated significant outward remodeling. Mean inner diameter of the ipsilateral versus contralateral LMCs were 44.5 ± 5.9 um versus 28.2 ± 1.2 um, respectively (p<0.02, 7-8 vessels from 3 mice). In contrast, the DMAs were unaltered in diameter, 35.2 ± 4.0 and 35.7 ± 3.1 um, respectively. VWF expression was significantly increased in the ipsilateral LMCs versus contralateral LMCs (2.8 fold, p<0.05) and versus ipsilateral DMAs (3.7 fold, p<0.02). The DMAs showed significantly lower VWF expression, which was unchanged between ipsilateral and contralateral hemispheres.

Conclusions:
We demonstrate that VWF is highly expressed in the remodeling LMCs (but not connecting DMAs) of the post-stroke brain. These findings suggest a novel and selective role for endothelial VWF in the LMC response to prolonged recruitment during ischemic stroke.
Abstract P787: Sexually Dimorphic Gene Expression Molecular Correlates of Improvement in Human Ischemic Stroke
Authors: Amini Hajar , Knepp Bodie , Hull Heather , Carmona-Mora Paulina , Hakoupian Marisa , Alomar Noor , Jickling Glen , Zhan Xinhua , Khoury Jane , Pancioli Arthur , Broderick Joseph , Ander Bradley P , Stamova Boryana , Sharp Frank R
Published: March 2021

Objective:
Ischemic stroke (IS) is sexually dimorphic for risk factors, age, heritability, causes, treatment, and outcome. We identified transcriptional correlates with 90-day outcome that differed between male and female IS subjects.

Methods:
RNA from 72 samples from 2 peripheral blood draws (at ≤3 and 24h post IS onset) was analyzed on Affymetrix U133 Plus 2 microarrays. These represented samples from 36 CLEAR trial IS patients treated with tPA with or without eptifibatide after the first blood sample within 3 hours of stroke onset. Changes in gene expression levels (deltaGE) between 3h and 24h were calculated and the association with percent NIH Stroke Scale (NIHSS) improvement from 3h to 90 days (% Improvement) examined. We used mixed-effects linear regression, including Treatment, Age, Sex, Vascular Risk Factors, 3h NIHSS, % Improvement, and a Sex * % Improvement interaction. Sex differences in association of gene expression with % Improvement were determined by examining the Sex * % Improvement interaction term, p<0.005 was considered statistically significant.

Results:
577 genes correlated differently with % Improvement in IS males and females. These included matrix metalloproteinases (MMPs), which play a major role in BBB dysfunction and outcomes post IS.
MMP11
,
MMP14
and
MM17
correlated with % Improvement in opposite direction in males and females. Inflammatory genes like
IL-27
, implicated in infarct volume and stroke outcome, and ABC transporters (
ABCC9
) also had opposite correlation with % Improvement in males and females. Calmodulin 1 (
CAML1
) was also sexually dimorphic, and a SNP in
CALM1
has been implicated in IS risk and blood coagulation in female IS patients. EIF2 signaling, a major protein synthesis pathway was activated in males (adj. p = 1e-8), while suppressed in females (adj. p value = 1e-9). Protein synthesis and associated unfolded protein response cascade have previously been implicated in stroke outcome.

Conclusions:
The identified sexually dimorphic gene expression associated with 90-day improvement might relate to sex differences in blood immune and clotting pathways. The findings expand our understanding of the genomic underpinnings associated with stroke outcome and may serve as potential sex-specific treatment targets.
Abstract P79: Decline in Mild Stroke Presentations and Intravenous Thrombolysis During the Covid-19 Pandemic: The Society of Vascular and Interventional Neurology Registry
Authors: Farooqui Mudassir , Ortega-Gutierrez Santiago , Zha Alicia , Czap Alexandra L , Jacob Sebaugh , Desai Shashvat , Jadhav Ashutosh , Vora Nirav , Rai Vivek , Jovin Tudor G , Thon Jesse , Heslin Mark , Thau Lauren , Zevallos Cynthia , Quispe-Orozco Darko , Jillella Dinesh , NAHAB Fadi B , Mohammaden Mahmoud , Nogueira Raul G , Haussen Diogo C , Nguyen Thanh , Romero Jose , Aparicio Hugo , Osman Mohamed , Haq Israr , Liebeskind David S , Hassan Ameer E , Zaidat Osama O , Siegler James E
Published: March 2021

Introduction:
To evaluate overall ischemic stroke rates, specific subtypes, and clinical presentation during the COVID-19 pandemic in a multicenter observational study from eight states across US.

Methods:
We compared all ischemic strokes admitted between January 2019 and May 2020, grouped as; March-May 2020 (COVID-19 period), March-May 2019 (seasonal pre-COVID period) and November 2019-January 2020 (immediate pre-COVID-19 period). Primary outcome was stroke severity at admission measured by NIHSS stratified as mild (0-7), moderate (8-14), and severe (>14) symptoms. Secondary outcomes were number of large vessel occlusions (LVOs), stroke etiology, IV-tPA rates, and disposition.

Results:
Of the 7,969 patients diagnosed with acute stroke during the study period, 933 (12%) presented in the COVID-19 period, 1319 (17%), and 1254 (16%) presented in the seasonal pre-COVID-19 and immediate pre-COVID-19 periods, respectively. Significant decline was observed in the weekly mean volume of newly diagnosed strokes (98±7.3 vs 50±20, p<0.01 and 95±10.5 vs 50±20, p<0.01), LVOs (16.5±3.8 vs 8.3±5.9, p<0.01 and 14.3± 4.5 vs 8.3±5.9, p<0.01), and IV-tPA (5.3±2.9 vs 10.9±3.4 and 12.7±4.1, p<0.01). Mean weekly proportion of LVOs remained the same, when compared with seasonal pre-COVID-19 period (18%±5 vs 16%±7, p=0.24) and immediate pre-COVID-19 period (17.4%±4 vs. 16%±7, p=0.32). Additionally, these patients presented with less severe disease (NIHSS<14; aOR: 0.63, 95%CI: 0.41-0.97, p=0.035) during the COVID-19 period as compared to immediate pre-COVID-19 period.

Conclusions:
We observed a decrease in newly diagnosed stroke cases and rates of IV-tPA administration, while the LVO frequency remained unchanged during the COVID-19 pandemic. Additionally, these stroke patients had more severe presentations.
Abstract P794: Neuregulin-1 Induction of a Distinct Neuronal Growth Program Profile Post-Ischemia
Authors: Noll Jessica , Ford Byron D
Published: March 2021

Stroke is ranked as the fifth leading cause of death and the leading cause of adult disability in the United States. Tissue Plasminogen Activator (tPA) is the only FDA approved stroke treatment. Unfortunately, tPA is only administered to 2-5% of patients due to risk of hemorrhage, and it has no therapeutic effect on neuroprotection or neurological recovery. Thus, there is no treatment capable of addressing progressive adult disability. However, it has been shown that exogenous Neuregulin-1 (NRG-1) significantly decreases acute neuronal death and neuroinflammation after ischemic injury. Furthermore, NRG-1 has demonstrated a neuroregenerative effect with increased neuronal sprouting, synapse formation markers, and functional recovery after ischemia. However, the spatiotemporal regenerative effects of NRG-1 following ischemia have not been clearly elucidated. This study aimed to define the endogenous and NRG-1 treatment induced neuronal growth program (NGP) by spatiotemporally characterizing neuroplasticity and neuronal gene expression after ischemic stroke. Male and Female Thy1-eGFP+ transgenic mice were given middle cerebral artery occlusion (MCAO). Mice were treated daily for 10 days, I.P., with vehicle (0.1% BSA, endogenous) or NRG-1 (5ug/kg, treatment-induced) starting 24 hours after MCAO and sacrificed at 10dpi. Confocal microscopy data indicate that NRG-1 daily I.P. treatment protects Thy1-eGFP+ cortical neurons and exhibits more processes and less debris within the peri-infarct tissue. NRG-1 treated mice also exhibited an increase in BCAS1+/Olig2+ oligodendrocytes within the ipsilateral cortex and Olig2+ cells in the ipsilateral subcortex and contralateral cortex compared to vehicle treated mice 24 hours after MCAO. Additional studies including digital spatial profiling (DSP) suggest a spatiotemporal regulation of transcriptional profiles initiated by endogenous and NRG-1 treatment-induced NGP. These studies will help determine whether NRG-1 amplifies endogenous neuroplasticity or induces a distinct and/or region-specific neuroplastic pathway.
Abstract P8: IV Alteplase Prior to Thrombectomy Benefitted Patients With M1 Occlusions but Not Thrombectomy Patients With M2 Occlusions
Authors: Tarpley Jason W , Stuchiner Tamela L , Ho Joseph T , Ovando Renee , Teitelbaum George P , Martin Neil , Kelly Daniel , Baraban Elizabeth
Published: March 2021

Introduction:
Endovascular Therapy (EVT) has overwhelming efficacy for the treatment of acute ischemic stroke due to large vessel occlusion. There is debate regarding whether the administration of IV-alteplase influences the efficacy of this powerful treatment. Here we examined whether M1 and M2 occlusion patients may have differential benefit from IV tPA prior to their EVT.

Methods:
Data from the Providence System Stroke Registry for acute ischemic stroke patients receiving EVT between January 2015 and May 2020 and who had an occlusion in M1 or M2 middle cerebral artery were used. Multinomial regressions were used to asses if EVT patients with an M1 or M2 occlusion who received IV tPA compared to those who did not were more likely to be discharged as expired or hospice or other location (acute care or long term care, skilled nursing facility, left against medical advice), compared to home or inpatient rehabilitation (IRF), adjusting for patient age, sex, race and ethnicity, last known well to arrival, and NIHSS at admit. Adjusted odds ratios (AOR) and 95% confidence intervals (95% CI) are reported.

Results:
A total of 667 EVT patients with an M1 occlusion were included in the analysis, of which 52.2% (n=348) received IV tPA and 47.8 (n=319) did not, and 273 EVT patients with an M2 were analyzed, of which 53.8% (n=147) received IV tPA and 46.2% (n=126) did not. The M1 MCA patients treated with IV tPA had 36% lower likelihood of being discharged somewhere other than home / IRF (AOR=0.64, 95% CI: 0.43, 0.94) than to home/IRF. Among M2 patients there were no differences found in the likelihood of being discharged expired/hospice or somewhere other home compared to home/IRF between those who did or did not receive IV tPA.

Conclusions:
Patients with M1 occlusions who received EVT and IV tPA had better discharge dispositions than those who did not receive IV tPA. However, patients with M2 occlusions who received EVT had equivalent discharge dispositions regardless of whether they got IV tPA or not. These results underscore the need for more randomized prospective clinical trials to evaluate the impact of thrombolysis on EVT patient outcomes and highlight the importance of evaluating lesion location as a potential covariate in these trials.
Abstract P800: Liposomal Delivery of PICK1 Inhibitor, FSC231, Prevents Ischemic/Reperfusion-Induced Degradation of GluA2 AMPA Receptor Subunit
Authors: Achzet Lindsay , Jackson Darrell A
Published: March 2021

Stroke remains to be a leading cause of disability within the United States. Despite an enormous amount of research effort within the scientific community, very few therapeutics are available for stroke patients. Cytotoxic accumulation of intracellular calcium is a well-studied phenomenon that occurs following ischemic stroke. This intracellular calcium overload results from excessive release of the excitatory neurotransmitter glutamate, a process known as excitotoxicity, eventually leading to delayed neuronal death. The hippocampus is particularly susceptible to AMPA receptor-mediated delayed neuronal death. AMPA receptors (AMPARs) are homo- or hetero-tetramers composed of GluA1-4 subunits. The majority of AMPARs are impermeable to calcium due to a post-transcriptional modification in the channel pore of the GluA2 AMPAR subunit. Calcium-permeable AMPARs lacking the GluA2 subunit, contribute to calcium cytotoxicity and subsequent neuronal death. The internalization and subsequent degradation of GluA2 AMPAR subunits following oxygen-glucose deprivation/reperfusion (OGD/R) is, at least in part, mediated by protein-interacting with C Kinase-1 (PICK1). We hypothesize that disrupting the PICK1—GluA2 interaction will prevent the degradation of GluA2, thereby protecting neurons within the hippocampus from AMPAR-mediated delayed neuronal death. Pretreatment with liposome-encapsulated FSC231, an inhibitor of PICK1, in acute rodent hippocampal slices prevents the OGD/R-induced association of PICK1—GluA2. FSC231 treatment during OGD/R rescues total GluA2 AMPAR subunit protein levels. This work is the first to utilize a liposomal drug delivery system for the delivery of a small molecule in
ex vivo
acute rodent hippocampal slices exposed to ischemia/reperfusion injury. These results suggest that the interaction between GluA2 and PICK1 serves as an important step in the ischemic/reperfusion-induced reduction in total GluA2 levels and is a potential therapeutic target for the treatment of ischemic stroke.
Abstract P804: Lopsided Blood-Thinning Drug Increases the Risk of Internal Flow Choking and Shock Wave Generation Causing Asymptomatic Stroke
Authors: V R Sanal Kumar ,   Indo-US Investigators on Asymptomatic Stroke and Acute MI
Published: March 2021

Introduction:
Consequence of lopsided blood-thinning-drug, lowering blood-viscosity (BV), is bleeding and very frequently asymptomatic-hemorrhage (AH) and the acute-heart-failure (AHF) happen. V.R.S.Kumar et al. (2020) reported that such asymptomatic episodes are due to the internal flow choking in the cardiovascular system (CVS) at a critical blood pressure ratio (BPR), which is regulated by biofluid/blood heat capacity ratio (BHCR).

Methods:
The closed-form-analytical-methodology is used for correlating BV, BPR, BHCR, vessel geometry and ejection fraction (EF). In vitro method is used for the BHCR estimation of healthy subjects. In silico method is used for demonstrating the Sanal flow choking.

Results:
The analytical models reveal that the relatively high and low BV are risk factors of internal flow choking.
In vitro
study shows that N
2
, O
2
, CO
2
& Ar gases are predominant in fresh-blood samples of the healthy subjects at a temperature range of 37-40
0
C (98.6-104
0
F), which increases the risk of flow-choking.
In silico
results demonstrated the
Sanal flow choking
followed by the shock wave generation and pressure-overshoot in a simulated artery with the divergent/bifurcation region.

Conclusions:
An overdose of blood-thinning drug reduces BV and increases
Reynolds number
causing high-turbulence leading to the
Sanal flow choking.
Asymptomatic stroke could be diminished by concurrently lessening the BV and flow turbulence by rising
thermal tolerance level
in terms of BHCR or by decreasing the BPR. In conclusion, BPR must always be lower than 1.8257 as dictated by the lowest BHCR of the evolved gas (CO
2
) for prohibiting asymptomatic stroke.
Abstract P812: Characterizing NMDA Receptor Subunits on B Cells
Authors: Malone Mary K , Torres Vanessa , Turchan-Cholewo Jadwiga , Stowe Ann M
Published: March 2021

Background:
N-methyl-D-aspartate (NMDARs) play a critical role in neuronal excitotoxicity after stroke. The actions of NMDARs have been shown mostly in obligatory GluN1 subunits on neurons and not GluN2A/B subunits. In B cells, these subunits have not been highly characterized though the presence of NMDARs has been shown. The function of the GluN2A/B subunits can be neuroprotective or pro-death in neurons, respectively. We hypothesized that GluN2A and GluN2B subunit presence on B cells would be affected by exposure to extracellular glutamate.

Methods:
Splenic B cells were isolated from 3-4mo-old C57BL/6 male mice via magnetic separation and treated with physiologic levels of L-glutamate (glu; 1uM) in the presence or absence of 5ug/mL LPS. B cell cytospins were stained for B220, GluN2A, and GluN2B, imaged using confocal microscopy, and quantified in FIJI. An average of 10.7 B cells were quantified per image at 80-157x magnification. RGB channels of the z-stacks were quantified to identify positive B220 expression. The z-stacks were split into 2D images and quantified plane-by-plane to identify GluN2A/B subunit clusters. Each cluster of subunits was recorded per cell in view across all planes of the original z-stack to yield total subunit count. Groups included 14-43 B cells quantified, and the number of subunits per cell were analyzed via ordinary two-way ANOVA, Sidak post-hoc test (Graphpad Prism). Significance was p<0.05.

Results:
There was an average of 19.3±7.2 GluN2A subunits and 19.0±5.0 GluN2B subunits per cell for unstimulated, untreated B cells. Neither glu treatment (p=0.23) nor LPS stimulation (p= 0.10) impacted the number of GluN2A subunits per B cell. LPS decreased GluN2B subunits when compared to unstimulated B cells (11.1±5.1 subunits; p=0.02). Glu treatment normalized GluN2B subunits per B cell near untreated baseline levels (18.2±11 subunits per cell; p=0.01), resulting in an interaction between LPS stimulation and glu treatment in B cells (F (1, 86) =6.180, P=0.015).

Conclusions:
Our data suggests activated B cells downregulate GluN2B-containing NMDARs following LPS stimulation. This downregulation mimics that of NMDAR activity on neurons upon excitoxicity (PMID: 24361499) but future studies should confirm GluN2B internalization.
Abstract P813: Enhanced Stress Response is Associated With Increased Inflammation and Worse Outcomes Following Ischemic Stroke in Diabetic Condition
Authors: Kim Eunhee , Kim Sehee , Park Eunsu , Chen Peng R
Published: March 2021

Introduction:
Although stroke severity is increased in patients with diabetes (e.g., higher mortality, larger infarcts, and worse neurological deficits), the underlying mechanism(s) of the worse outcomes is not clear. Evidence shows that hypothalamic-pituitary-adrenal (HPA) axis is dysregulated and cortisol levels are increased in diabetes. Based on the role of HPA axis in immunity, we hypothesized that diabetes-enhanced stress response contributes to stroke injury via regulating inflammation.

Methods:
Diabetes was induced in C57BL/6 mice by feeding a diabetogenic diet and injecting streptozotocin. Mice were subjected to 30 min middle cerebral artery occlusion. Infarct volume and neurological scores were measured at 24h-post stroke. We measured expression of factors related to stress response, plasma corticosterone, c-Fos and corticotropin-releasing factor (CRH) in hypothalamus, and proopiomelanocortin (POMC) and corticotropin-releasing hormone receptor 1 (CRHR1) in pituitary. Inflammatory cytokine levels were also determined in the ischemic brain.

Results:
Diabetic mice showed hyperglycemia and delayed glucose clearance in blood. At 1d-post stroke, diabetic mice showed larger infarct and worse neurological score. Plasma corticosterone levels were significantly increased in diabetic mice. We also found increased c-Fos in hypothalamus, and CRHR1 and POMC in pituitary. These were accompanied by increased IL-1β, TNF-α, and IL-6 mRNA in the ischemic brain.

Conclusion:
Our results indicate that stress response is enhanced in diabetic conditions, and associated with increased inflammation in ischemic brain and worse stroke outcomes. It suggests that regulation of stress response may improve stroke outcomes in diabetic conditions.
Abstract P814: Complex Movement Representations of Mouse Motor Cortex After Experimental Stroke
Authors: Wolsh Cassandra , Brown Andrew R , Woodard Samuel W , Lopez Monica M , Boychuk Jeffery A
Published: March 2021

Stroke injury and incomplete long-term stroke recovery remain key health issues in the United States and world-wide. We seek to help identify cellular dysfunction of the motor cortex after stroke, and its possible circuit remodeling during stroke recovery, since this structure is heavily implicated in this biology. We propose to measure evoked motor responses during long-train intracortical microstimulation (LT-ICMS) of motor cortex in the mouse as a method to identify the functional organization of this structure and plasticity following experimental stroke that relates to functional recovery. This work is one of the first to use LT-ICMS in mice after experimental stroke and it is employed in this study because it evokes complex, multi-joint forelimb movements that may match the temporal activity patterns of motor cortical cells during volitional movement and relate to skilled motor behavior. Permanent stroke injury is induced here using photothrombotic occlusion of the distal middle cerebral artery (MCAo) using Rose Bengal dye and green laser photostimulation. Skilled motor behavior is tested using the single pellet reaching task. Each mouse completes 30 days of post-injury or sham-injury single pellet reaching that is followed by an evaluation of cortical forelimb movement representation using LT-ICMS and then histological testing of lesion size and location. LT-ICMS is delivered as 500 millisecond trains of biphasic 200 microsecond pulses (delivered at 333 Hz) via a platinum/iridium microelectrode. The microelectrode is applied to test sites across the motor cortex (354 micron spacing) that are each at a depth of 800 microns. Evoked movements to LT-ICMS are quantified using high-speed video kinematic tracking of the forelimb. Experimental blind conditions are maintained until study completion. Statistics are then used to relate outcomes of behavioral reaching, LT-ICMS, and lesion characteristics. Collectively, the goal of this project is to understand whether (and how) complex movement representations derived by LT-ICMS change during stroke recovery in order to guide rehabilitative and interventional stroke therapies.
Abstract P823: Evaluating Time-To-Aneurysm Repair as a Performance Measure in Aneurysmal Subarachnoid Hemorrhage
Authors: Sheehan Tiffany O , Davis Nicolle W , Guo Yi , Lynch Kelly Debra , Yoon Saun-joo , Horgas Ann
Published: March 2021

Background:
Implementation of evidence-based performance metrics drive standardized care and improve patient outcomes. Limited performance metrics have been developed for implementation in the aneurysmal subarachnoid hemorrhage (aSAH) population. Timely aneurysm repair following an aSAH is associated with rebleeding prevention and mortality. The purpose of this study was to evaluate time to aneurysm repair as a candidate performance metric by testing a model that includes hospital and patient characteristics as predictors of time to aneurysm repair and mortality, with time to aneurysm repair as a potential influence on these relationships in aSAH.

Methods:
A retrospective, cross-sectional analysis of patient discharge data from 2014 in the state of Florida was conducted. Data were derived from The Agency for Healthcare Research and Quality, HealthCare Utilization Project, State Inpatient Dataset, and the American Hospital Association Annual Survey. Patients with a primary ICD-9 diagnosis of aSAH and principle procedure of clipping or coiling were included (n=387). The study outcome was in-hospital mortality. Independent variables were level of stroke center, age, race, sex, and type of aneurysm repair. Hierarchical logistic regression was used to estimate the probability of in-hospital death.

Results:
Patients who underwent endovascular repair of an aneurysm were more likely to be treated in <24 hours compared to those undergoing aneurysm clipping (OR = 0.54, CI = .35-.84,
p
=0.01). Patients treated at a comprehensive stroke center (CSC) had a 72% reduction in odds of death compared to those treated at primary stroke centers (OR =0.28, CI = 0.10-0.77,
p
=0.01), controlling for disease severity and comorbidity. Time to aneurysm repair was not significantly associated with mortality and did not influence the relationship between hospital and patient characteristics and mortality.

Conclusions:
Treatment at a certified CSC was the only significant predictor of surviving aSAH. Time to aneurysm repair did not influence the relationship between hospital and patient characteristics associated with mortality. Further research is needed to identify appropriate measures and to define what should be tracked for performance in the aSAH population.
Abstract P842: The Effectiveness of an Aspiration Pneumonia Prevention Program in Acute Ischemic Stroke Patients
Authors: poohkam Jiraporn , Meemak Janya , Sukhanthaman Matthariya , Pinyopasakul Wanpen , Koositamongkol Sarunya , Wongsurakiat Phunsup , Nilanont Yongchai
Published: March 2021

Background:
Pneumonia after stroke leads to poor clinical outcome. The aspiration risk increases in patients with dysphagia. This study aims to evaluate the effects of pneumonia prevention program following acute ischemic stroke (AIS).

Methods:
This was a prospective pre/post intervention study. AIS patients aged > 18 years with swallowing difficulties were enrolled. The pneumonia prevention program consisted of respiratory muscle training and oral care protocols. The program was provided during a 2-week hospitalization in all participants. Cough flow measurements and oral health status were evaluated using Cough Peak Flow (CPF) and Oral Assessment Guide (OAG) score respectively. Outcomes were measured at baseline and 2 weeks after randomization. Pneumonia incidence was collected at baseline, 2 weeks, and 1, 3, 6, and 12 months. Data were analyzed using descriptive statistics and paired t- test.

Results:
Nine females and 7 males were recruited with a mean
+
SD age of 67.5
+
8.7 years old. Median initial NIHSS (min, max) was 9 (4, 15) and 9 (2, 15) at baseline and 2 weeks respectively. Oral Assessment Guide (OAG) score improved in 15 patients (93.7%). Higher Cough Peak Flow (CPF) (> 160 L/min) was found in 87.5%. The OAG score was significantly lower (p < 0.05) at 2 weeks showing a significant improvement. There was also a statistically significant improvement of CPF at 2 weeks (p < 0.001). No aspiration pneumonia was diagnosed during the study.

Conclusions:
Pneumonia prevention program was effective in improving oral health status and cough reflex following AIS. The program can be applied as early as possible. Further studies with larger sample size and a control group are required.