Background Stroke is a sexually dimorphic disease, with different risk factors, incidence, outcomes, and treatment responses in men and women. While sex differences have been documented in preclinical studies, these findings often come from single-site studies with small sample sizes and require validation across diverse research settings.Methods We used data from the SPAN (Stroke Preclinical Assessment Network), a randomized, placebo-controlled, blinded, multilaboratory trial, to determine if sex differences in neurological outcomes are present in preclinical stroke models. We analyzed data from 665 stroke animals treated with saline, including young mice, diet-induced obese mice, aging mice, young rats, and spontaneously hypertensive rats. We compared the corner test index and brain morphology between the sexes using linear random effect models and assessed the mortality rate using Cox proportional hazard regression models.Results No significant sex differences were found in neurological outcome measured with the corner test on either day 7 or day 30 after stroke, regardless of the mouse or rat stroke model used. Additionally, female and male mice exhibited similar infarct sizes on day 2 magnetic resonance imaging and on brain atrophy measures on day 30 after stroke, indicating a lack of sex differences in brain injury. Similarly, no sex differences were observed in acute or chronic sensorimotor or tissue outcomes in young rats. In 1 subanalysis, sex differences were seen in the spontaneously hypertensive rats cohort. Female rats exhibited a higher corner test index on day 30 than males, indicating more severe sensorimotor injury.Conclusions In this multicenter preclinical study, we did not detect sex differences in stroke outcomes in mice, although sex differences in behavioral outcomes were observed in spontaneously hypertensive rats. These findings highlight that sex differences may be model-specific and subtle, emphasizing the need for methodological consistency and thoughtful inclusion of diverse animal models in translational stroke research to better understand if sex-specific responses contribute to stroke outcomes.

Objectives: No single animal stroke model satisfies all needs of translational stroke investigation. While the nylon filament MCAo model is widely accepted in preclinical translational stroke research, thromboembolic models have more physiological relevance. Thromboembolic models are technically difficult, time consuming, and show variable results, however, rendering them less utilizable for widespread deployment in a multi-laboratory preclinical network. We sought to develop and validate a standardized thromboembolic middle cerebral artery occlusion model that encompasses vessel occlusion and subsequent thrombolysis. Methods: To reduce the numbers of donor animals required, we developed a method to store donor blood for later use. Using prefabricated microcatheters, we simplified thrombus preparation and handling. For thrombolysis we used intravenous Tenecteplase dosing at 1.5mg/kg. To demonstrate feasibility and ease-of-use, the model was implemented at six research laboratories. We wrote and field-tested standard operating procedures, training videos, and hands-on surgical training workshops. Results: We enrolled 170 Sprague Dawley rats—some of which were only used as blood donors—of both sexes at six laboratories which performed 4 to 6 thrombus embolizations per week. All laboratories achieved reproducible occlusion and thrombolysis. Thromboemboli prepared from stored blood worked as well as emboli from freshly drawn blood. Of 135 rats who received one embolus, 33 (24%) died before 48-hour MRI scan. In survivors, stroke volume was 13±16% of the ipsilateral hemisphere. Corner test, neurobehavioral battery, and MRI showed reasonably consistent stroke injury. Conclusions: We established the feasibility and reproducibility of a multi-laboratory rodent thromboembolic model. All sites, including novice surgeons, mastered the surgical protocol. Numbers of surgeries per week would allow high-throughput testing.

Background: Between 2.2% and 17% of all strokes in the United States occur during hospitalization, often in non-acute care settings and among patients admitted for cardiovascular and/or surgical procedures. While emergency departments are supported by well-established stroke systems, the identification and management of in-hospital strokes outside these environments remain under-characterized. These settings often lack standardized training, protocols, or stroke infrastructure, contributing to delays in diagnosis and treatment. This represents a critical gap in stroke care delivery. Methods: We conducted a retrospective review of all acute stroke team activations at the University of Southern California Keck Hospital—a tertiary non-acute care facility without an emergency department—from October 2021 through December 2024. Data were collected on presenting symptoms, imaging, final diagnoses, and use of acute interventions. Primary outcomes included the frequency of confirmed ischemic and hemorrhagic strokes, transient ischemic attacks (TIAs), and use of reperfusion therapies such as intravenous alteplase (IV-tPA) or mechanical thrombectomy. Results: A total of 346 code strokes were activated. Of these, 20.8% were confirmed ischemic strokes, 7.2% hemorrhagic strokes, 4.6% TIAs, and 2.2% stroke recrudescence. The remaining 64.7% were adjudicated as stroke mimics. Reperfusion therapy was infrequent: 6 patients (1.7%) received IV thrombolysis, and 10 (2.9%) underwent thrombectomy. Among ischemic strokes, 37.5% were peri-procedural, related to recent cardiovascular surgeries. Mimics were most often due to encephalopathy or delirium (30.1%), with seizures (6.1%) and headaches (2.0%) less common. Altered mental status alone triggered 13 activations, none due to stroke, though all had neurological causes. Conclusion: Over this 4-year period, only 35.3% of code stroke activations were confirmed cerebrovascular events. More than one-third of ischemic strokes were peri-procedural, and most activations were for mimics—especially encephalopathy and delirium. These findings highlight the high mimic rate and low reperfusion therapy use in a non-acute care setting. We propose targeted training and tailored protocols to improve diagnostic accuracy, reduce unnecessary activations, and optimize care. Stroke nurse evaluations or expedited neurology consults may improve resource use.

The concept of vascular neurology-specific education was launched nearly 50 years ago in response to a growing understanding of the pathophysiology of stroke. The vascular neurology field, and the training required to support its growth and evolution, has been heavily influenced by a simultaneously increasing breadth of knowledge in approaches to clinical management of stroke. There are increasing numbers of vascular neurology fellows each academic year, yet we continue to experience shortages in clinical coverage for patients with vascular neurological conditions. Here, we review the origins of vascular neurology training and current challenges in sustaining educational programs. We then propose action items to help shape the future of vascular neurology education.

No single animal stroke model satisfies all needs of translational stroke investigation. While the nylon filament model is widely accepted in preclinical translational stroke research, thromboembolic models have more physiological relevance. Thromboembolic models are technically difficult, time consuming, and show variable results, making them problematic for multi-laboratory preclinical network use. We sought to develop and validate a multi-laboratory thromboembolic middle cerebral artery occlusion model that encompasses vessel occlusion and subsequent thrombolysis. To reduce the numbers of donor animals used, we developed a method to store donor blood for later use. Using prefabricated microcatheters, we simplified thrombus preparation and handling. Emboli were prepared in microcatheters and injected directly into the middle cerebral artery from the internal carotid artery. For thrombolysis we used intravenous Tenecteplase dosing at 1.5 mg/kg. To demonstrate feasibility and ease-of-use, the model was implemented at six research laboratories. We wrote and field-tested standard operating procedures, training videos, and hands-on surgical training workshops. We enrolled 170 Sprague Dawley rats of both sexes at six laboratories who performed 4 to 6 thrombus embolizations per week. All sites could achieve reproducible occlusion and thrombolysis. Thromboemboli prepared from stored blood served as well as emboli from freshly drawn blood. Of 135 rats who received one embolus, 33 (24

Background: Behavioral deficits in mouse stroke models are often short-lived and lack significant correlation with stroke lesion volume. These limitations pose a challenge for assessing therapeutic interventions. The Stroke Preclinical Assessment Network phase 2, stage 1 (SPAN 2.1) was a multi-center, multi-stage preclinical study of cerebroprotectants combined with reperfusion. In this study, we explored the most significant long-term metrics for indicating (i) post-MCAO deficits and (ii) stroke lesion volume in mouse models at a single SPAN 2.1 site. Methods: Mice (n=58) from 3 groups of young healthy (~4 mo), diet-induced obese (~4 mo), and aged mice (~17 mo) underwent 60 min MCAO followed by 30 (±2) days of reperfusion. Stroke lesion volume was measured day-3 post-MCAO using MRI. Bodyweight loss, 9-item neurobattery score, corner test turn ratio, Y-maze percent alternation, and PhenoTyper activity (daytime/nighttime movement) were correlated to stroke lesion volume and compared to baseline data. Neurobattery was also analyzed by subtest: spontaneous activity, circling, symmetry of four limbs, forepaw outstretching, trunk sensation, vibrissae sensation, face sensation, beam-walking, and grid-climbing. Baseline PhenoTyper data was not collected. Results: There was a significant deficit between the baseline and turn ratio (p<0.0001), total neurobattery score (p<0.0001), circling (p<0.0001), symmetry of four limbs (p<0.0001), forepaw outstretching (p<0.0001), trunk sensation (p<0.0001), beam-walking (p=0.0003), percent alternation (p=0.0005), bodyweight loss (p=0.006), vibrissae sensation (p=0.0105), and face sensation (p=0.0183). There was not a significant deficit for spontaneous activity or grid-climbing (p>0.05). Among all endpoint metrics, bodyweight loss had the most significant correlation to stroke lesion volume (r=-0.5054, p=0.0005), while beam-walking also had a significant correlation (r=0.2817, p=0.0322). Other metrics did not correlate significantly with stroke lesion volume (p>0.05). Conclusion: Although not commonly viewed as a long-term metric for assessing post-MCAO deficits, bodyweight loss was the most significant predictor of both stroke lesion volume and behavioral deficits in SPAN 2.1 mice. Beam-walking was also a significant predictor of stroke lesion volume and behavioral deficits, though to a lesser extent. While other endpoint metrics were significantly different from baseline data, they did not reliably reflect stroke lesion volume.

Cerebral blood flow is a critical metric for cerebrovascular monitoring, with applications in stroke detection, brain injury evaluation, aging, and neurological disorders. Noninvasively measuring cerebral blood dynamics is challenging due to the presence of scalp and skull, which obstruct direct brain access and contain their own blood dynamics that must be isolated. We developed an aggregated seven-channel speckle contrast optical spectroscopy (SCOS) system to measure blood flow and blood volume noninvasively. Each channel, with a distinct source-to-detector distance, targeted different depths to detect scalp and brain blood dynamics separately. By briefly occluding the superficial temporal artery, which supplies blood only to the scalp, we isolated surface blood dynamics from brain signals. Results on 20 subjects show that scalp-sensitive channels experienced significant reductions in blood dynamics during occlusion, while brain-sensitive channels experienced minimal changes. This provides experimental evidence of scalp blood flow sensitivity in diffuse optical measurements such as SCOS, highlighting optimal configuration for preferentially probing brain signals noninvasively.

BACKGROUND:The National Institutes of Health Stroke Scale is used globally to rate neurological deficits in patients with acute stroke. Originally designed for research use, the scale uses idiosyncratic scoring rules and requires thorough training for proper use. Currently available training and certification systems are timeworn and limited in the range of demonstrated neurological findings. We aimed to develop a new training and certification method to address the limitations of the prior system. METHODS:We describe a new animated system that uses state-of-the-art digital motion capture, avatar rendering, and digital animation that enables illustration of all possible scale item responses within a training module. For certification, we created 20 unique case vignettes, which can be viewed from many angles allowing better scoring scenario presentation. Training to use the scale via telemedicine was added. Alpha and beta testing was completed to enhance iterative development. From a penultimate version, we measured interrater agreement among 42 pilot users who each viewed 6 cases. After further improvement, we finalized the application and confirmed interrater agreement in a second sample of 365 consecutive, unselected users viewing 3 cases. Clinometric analysis methods followed our prior studies of the scale. RESULTS:Users agreed the new, animated training module is more engaging and informative than legacy training videos. We compared the new system to the legacy live-video certification system for clinometric reliability. In the confirmatory sample, the intraclass correlation coefficient was 0.979 (97.5% CI, 0.919-0.99). Kappa scores ranged from 0.25 to 0.90 across all 15 scale items. These results are comparable to previous studies. CONCLUSIONS:A new, animated training and certification system showed equivalent clinometric properties to legacy systems, providing a reliable method for National Institutes of Health Stroke Scale training and certification. The new system allows modification and reconfiguration if needed to maintain user interest and case novelty.

BACKGROUND:To maintain procedural proficiency and certification according to the standards set by The Joint Commission-which accredits health care centers in the United States-thrombectomy-capable stroke centers (TSCs) must achieve a minimum annual procedural volume. The addition of thrombectomy-capable centers in a regional stroke care system has the potential to increase access but also to decrease patient presentations and procedural volume at nearby centers. This study sought to characterize the impact of certifying additional thrombectomy-capable centers on procedural volume by center in a large, urban Emergency Medical Services (EMS) system. METHODS:Data were collected from each designated thrombectomy-capable center in Los Angeles (LA) County from January 1, 2018 through June 30, 2022, during which a net total of five thrombectomy-capable centers were newly designated in the County. Per center volume for ischemic stroke presentations, intravenous (IV) thrombolysis administrations (IV tissue plasminogen activator [tPA]), and thrombectomy were tabulated by six-month interval. Median last-known-well-to-procedure times by LA County Public Health service planning area (SPA) were calculated. The effect of the number of designated centers on procedural volumes per center and median last-known-well-to-procedure times were analyzed via a linear mixed effects model with a log link function. RESULTS:Procedural volume, ischemic stroke presentation volume, and last-known-well-to-procedure times had high variability over the time period studied. Nonetheless, the median values for each metric in this EMS system remained largely stable over the study period. There was no statistically significant association between the number of thrombectomy-capable centers and per center procedural volumes or times-to-procedure. CONCLUSION:The designation of additional thrombectomy-capable centers in a regional stroke care system was not significantly associated with the volume of procedures by center or times-to-procedure, suggesting that additional centers may increase patient access to time-sensitive interventions without diluting patient presentations at existing centers.

BACKGROUND:The SPAN (Stroke Preclinical Assessment Network) is a confirmatory trial platform to test the efficacy and safety of candidate cerebroprotective interventions in acute stroke. As the largest multicenter preclinical stroke trial to date, the SPAN1 trial (first SPAN) prospectively captured many biological and procedural variables, revealing a high degree of heterogeneity introduced by the multicenter approach that may impact stroke outcomes. Here, we examined the biological and procedural predictors of tissue and neurological outcomes after focal cerebral ischemic stroke in rats. METHODS:SPAN1 enrolled and randomized 698 rats to various active treatment arms or controls. Rats were subjected to transient middle cerebral artery occlusion for 60 (spontaneously hypertensive rats) or 120 minutes (young, healthy Sprague-Dawley rats) and followed for 1 month. Eight biological and procedural independent variables (sex, weight, strain, intervention arm, site, endovascular filament silicone tip coating characteristics, anesthesia duration, and intervention protocol) and 5 dependent outcome variables (weight loss, 4-point neuroscore, corner test, infarct volume, and mortality) were captured. Multivariable regression was used to identify independent predictors of each outcome readout and determine their effect sizes. RESULTS:Spontaneously hypertensive rats exhibited larger infarcts than Sprague-Dawley rats, particularly among females. Neuroscores were also worse in spontaneously hypertensive rats. Prolonged anesthesia exposure was associated with smaller cortical and hippocampal infarcts. Filament thickness and length showed a complex association with different regional infarct volumes, neuroscores, weight loss, and corner test outcomes. Mortality was worse among females. Bivariate analysis of dependent variables revealed moderate correlations among the tissue and neurological outcomes. CONCLUSIONS:Using the large and multicenter, prospective SPAN1 dataset, our multivariable analyses identified several predictors influencing rat middle cerebral artery occlusion outcomes and refuted others previously reported. Investigators should consider whether biological and procedural predictors identified herein should be standardized, accounted for, or stratified during subject allocation to decrease variability and avoid confounders in future multicenter preclinical trials.

Inflammation, particularly mediated through interleukin-6 (IL-6) signaling, plays a critical role in stroke pathophysiology. High levels of IL-6 are associated with poor outcomes in stroke patients. Therapeutic inhibition of IL-6 signaling may offer a novel strategy to mitigate post-stroke damage and improve recovery. This study evaluated the efficacy of tocilizumab (TCZ), a clinically approved monoclonal antibody that blocks IL-6 receptor signaling, using data from the Stroke Preclinical Assessment Network (SPAN), a multi-center, randomized, blinded, placebo-controlled trial in preclinical stroke models. Methods We analyzed behavioral and MRI morphometry data from 701 rodents (both males and females; 1:1), including healthy young mice, diet-induced obese mice, aging mice, and spontaneously hypertensive rats (SHR) treated with saline (N=348) or TCZ (N=353) at a dose of 100 mg/kg for mice, 10 mg/kg for rats after middle cerebral artery occlusion (MCAO). Results : In the overall mouse cohort, TCZ did not significantly improve long-term sensorimotor recovery or reduce brain tissue loss measured by MRI. However, aging mice exhibited modest motor function improvements. In SHRs, TCZ treatment resulted in improved sensory-motor function, particularly in male rats, as demonstrated by enhanced corner test scores on days 7 and 28 post-MCAO. While TCZ in SHRs provided early (day 2) cerebroprotection with reduced lesion volume, it did not alter subsequent tissue loss, as measured by tissue atrophy at day 30. Conclusions These results suggest that IL-6R blockade with TCZ was associated with functional improvement in aging mice (modest) and hypertensive rats (notably males), without durable effect of brain tissue loss. No benefit was observed in the overall mouse cohort. These findings support IL-6 signaling as a viable therapeutic target and warrant further investigation into IL-6 receptor inhibition as a potential treatment strategy for stroke recovery.

BACKGROUND:The severity of early neurologic deficits after stroke is the single most important predictor of post-stroke outcomes. Of all stroke severity scales, the National Institutes of Health Stroke Scale (NIHSS) is the most widely used. Despite being freely accessible, however, this tool remains underutilized in sub-Saharan Africa (SSA) likely due to absence of culturally adapted translations. For this reason, we translated the NIHSS to Swahili in a bid to promote its local use as an initial measure in the standardization of stroke care in the East African region. Swahili remains among the 10 most commonly spoken languages in the world, with over 200 million speakers, mostly centred in East Africa. METHODS:The NIHSS was translated into Swahili by a team of native Swahili speakers composed of two stroke physicians, two speech therapists and one nurse, and three independent translators in collaboration with the tool's developer. Two Swahili translators performed forward translations of the original document from English to Swahili while a third independent translator performed backward translations to English, which was followed by clinician and cognitive reviews. Afterwards, reviewers from Kenya and Tanzania reviewed the tool for cross-cultural adaptation and international harmonisation. We further reconciled and generated a draft tool that was validated in Kenya and Tanzania. RESULTS:The NIHSS was translated into Swahili, a process that involved broad modifications of the tool including alterations of images, words and phrases to more locally familiar scenes and items. The results of validation of the Swahili version of the NIHSS in Kenya and Tanzania showed no significant differences with the original tool; with good interrater reliability in most domains. CONCLUSIONS:The result of this process is a Swahili translation of the NIHSS that reflects the original tool. We expect the tool to help advance stroke care in Swahili-speaking regions.

The addition of direct thrombin inhibitors or glycoprotein platelet inhibitors to intravenous thrombolysis in patients undergoing endovascular thrombectomy for acute ischemic stroke may improve reperfusion rates and clinical outcomes. To investigate the safety and efficacy of these agents. This was a preplanned cohort analysis from the Multi-Arm Optimization of Stroke Thrombolysis (MOST) randomized clinical trial, which lasted from 2019 to 2023 with a 90-day follow-up. Centrally read outcomes were assessed blinded to treatment. The MOST study was a multicenter, multiarm, adaptive, single-blind, phase 3 trial that included patients with acute ischemic stroke who were selected for thrombectomy per standard of care. Patients were randomized to placebo, argatroban, or eptifibatide within 75 minutes of intravenous thrombolysis. The 90-day utility-weighted modified Rankin Scale (UW-mRS) score (range, 0-10, with higher scores reflecting better outcomes) was used as the primary outcome measure. Reperfusion rates and safety (hemorrhage rates) were also assessed, where good reperfusion was defined as a Thrombolysis in Cerebral Infarction score of 2b/2c/3 on the completion angiogram. A total of 5376 patients were assessed for eligibility. Of these individuals, 4332 did not meet inclusion criteria, 251 eligible patients did not have consent obtained, 279 were excluded for other reasons, and 514 were randomized in the MOST trial. A total of 254 were planned for thrombectomy (110 in the placebo group, 31 in the argatroban group, and 113 in the eptifibatide group). Mean (SD) age was 68 (14.3) years, and 134 (53%) were female. Of these patients, 219 received thrombectomy: 94 in the placebo group, 27 in the argatroban group, and 98 in the eptifibatide group. There was no effect of treatment on outcome (mean UW-mRS score: eptifibatide, 6.47; 95% CI, 5.79-7.15; argatroban, 5.35; 95% CI, 4.13-6.58; placebo, 6.68; 95% CI, 5.98-7.39). Rates of good reperfusion were similar between groups (83 of 92 in the placebo group [83%]; 17 of 27 in the argatroban group [63%], and 82 of 98 in the eptifibatide group [84%]). The proportion of symptomatic intracranial hemorrhage was similar between groups. Results of this secondary analysis of the MOST randomized clinical trial reveal that the addition of argatroban or eptifibatide to intravenous thrombolysis was not associated with better reperfusion rates or clinical outcomes in patients undergoing endovascular thrombectomy. Future investigations of these agents as intravenous adjuncts to thrombectomy should focus on populations who are ineligible for intravenous thrombolysis. ClinicalTrials.gov Identifier: NCT03735979

Preclinical stroke research faces a critical translational gap, with animal studies failing to reliably predict clinical efficacy. To address this, the field is moving toward rigorous, multicenter preclinical randomized controlled trials (mpRCTs) that mimic phase 3 clinical trials in several key components. This collective statement, derived from experts involved in mpRCTs, outlines considerations for designing and executing such trials. mpRCTs offer advantages such as increased sample sizes, robust statistical design, incorporation of heterogeneity, and standardized protocols, but they face challenges in finding the right balance between standardization and heterogeneity, appropriate stroke model selection, and outcome measures, as well as the implementation of complex network infrastructure. We discuss the importance of rigorous study design, including appropriate stroke models, representation of biological variables and comorbidities, functional outcome readouts, and handling of attrition and mortality. Statistical considerations such as adaptive sequential designs, covariate adjustments, and appropriate handling of missing data are also addressed. The integration of machine learning, the implementation of common data elements, and the selection of appropriate therapeutic candidates are crucial for maximizing the efficiency and utility of mpRCTs. Furthermore, the transition toward mpRCT platforms, akin to clinical trial platforms, holds promise for facilitating continuous evaluation of therapies. Finally, we discuss data-sharing practices and the collateral benefits of mpRCTs, emphasizing their potential to improve preclinical stroke research and bridge the translational gap. Altogether, we hope that this article will serve as a starting point for a lasting debate on the future of stroke mpRCTs and their evolution toward a universally accepted set of principles.

Current translational rodent stroke models induce middle cerebral artery occlusion (MCAo) using nylon filaments, injected emboli, intraluminal thrombin, or perivascular endothelin-1 to simulate human stroke. Among these methods, thromboemboli injection followed by thrombolysis best mimics the neuroinflammatory events seen in human patients and may be preferable to the inert nylon filament method most widely used. The standard thromboembolic models, used in leading single laboratories, however, can be time-consuming, produce variable results, and require considerable skill to master. To address these limitations, we developed a thromboembolic MCAo model that targets vessel occlusion and uses intravenous thrombolysis to achieve recanalization, paralleling the systemic thrombolysis administered in clinical scenarios. To reduce the number of animals, we developed a method to store blood from donor animals for later emboli preparation for multiple subjects. Our utilization of prefabricated Doccol microcatheters simplifies thrombus preparation and injection by pre-loading thromboemboli into the microcatheters that are then inserted into the internal carotid artery. To achieve recanalization, we infused intravenous Tenecteplase at a dose of 1.5 mg/kg. To promote reproducibility, we prepared and field-tested standard operating procedures, training videos, and hands-on surgical training workshops. The model uses a standard surgical approach that should be familiar to all investigators who use the widely accepted nylon filament model. Passage of the microcatheter into the distal internal carotid artery, avoiding the pterygopalatine artery, is accomplished in a manner similar to the nylon filament insertion. Recovery and post-stroke assessments may be done with typical behavioral, radiographic, and histologic protocols. This model offers a practical, reproducible, and accessible approach for investigators seeking a thromboembolic MCAo model with controlled recanalization.