Cortical Ischemic Stroke Research Articles

Interaction between subventricular zone microglia and neural stem cells impacts the neurogenic response in a mouse model of cortical ischemic stroke

After a stroke, the neurogenic response from the subventricular zone (SVZ) to repair the brain is limited. Microglia, as an integral part of the distinctive SVZ microenvironment, control neural stem / precursor cell (NSPC) behavior. Here, we show that discrete stroke-associated SVZ microglial clusters negatively impact the innate neurogenic response, and we propose a repository of relevant microglia–NSPC ligand–receptor pairs. After photothrombosis, a mouse model of ischemic stroke, the altered SVZ niche environment leads to immediate activation of microglia in the niche and an abnormal neurogenic response, with cell-cycle arrest of neural stem cells and neuroblast cell death. Pharmacological restoration of the niche environment increases the SVZ-derived neurogenic repair and microglial depletion increases the formation and survival of newborn neuroblasts in the SVZ. Therefore, we propose that altered cross-communication between microglial subclusters and NSPCs regulates the extent of the innate neurogenic repair response in the SVZ after stroke.

Optical coherence tomography enables longitudinal evaluation of cell graft-directed remodeling in stroke lesions.

Stem cell grafting can promote glial repair of adult stroke injuries during the subacute wound healing phase, but graft survival and glial repair outcomes are perturbed by lesion severity and mode of injury. To better understand how stroke lesion environments alter the functions of cell grafts, we employed optical coherence tomography (OCT) to longitudinally image mouse cortical photothrombotic ischemic strokes treated with allogeneic neural progenitor cell (NPC) grafts. OCT angiography, signal intensity, and signal decay resulting from optical scattering were assessed at multiple timepoints across two weeks in mice receiving an NPC graft or an injection of saline at two days after stroke. OCT scattering information revealed pronounced axial lesion contraction that naturally occurred throughout the subacute wound healing phase that was not modified by either NPC or saline treatment. By analyzing OCT signal intensity along the coronal plane, we observed dramatic contraction of the cortex away from the imaging window in the first week after stroke which impaired conventional OCT angiography but which enabled the detection of NPC graft-induced glial repair. There was moderate, but variable, NPC graft survival at photothrombotic strokes at two weeks which was inversely correlated with acute stroke lesion sizes as measured by OCT prior to treatment, suggesting a prognostic role for OCT imaging and reinforcing the dominant effect of lesion size and severity on graft outcome. Overall, our findings demonstrate the utility of OCT imaging for both tracking and predicting natural and treatment-directed changes in ischemic stroke lesion cores.

Embolic Ischemic Cortical Stroke in a Young Flight Instructor with a Small Patent Foramen Ovale

BACKGROUND: Stroke in young patients is frequently associated with a patent foramen ovale (PFO). Controversy exists over whether the PFO is a cause, a risk factor, or an incidental finding. Estimating the individualized risk of stroke recurrence has been difficult to ascertain. This has implications for aeromedical certification for pilots following stroke recovery. CASE REPORT: A 28-yr-old male flight instructor presented with sudden onset unilateral facial paresthesia, hand weakness, and blurred vision, accompanied by gradual onset bilateral headache. While the cranial symptoms resolved, left hand weakness persisted for 3 d. MRI revealed two punctate ischemic foci in the right precentral gyrus and superior parietal lobe. A transesophageal echocardiogram revealed a PFO with a small bidirectional shunt. His cardiologist and neurologist advised the PFO was unlikely to have caused his stroke and estimated an annual recurrence rate of < 1.8%. He was treated medically and declined PFO closure. He was able to return to flying light-sport aircraft. However, an enduring copilot restriction for general aviation activities was placed on his Class 1 and 2 medical certificates. DISCUSSION: This case highlights the difficulty in determining individualized recurrence risks for pilots recovering from a stroke associated with a PFO. While medical treatment does reduce the risk of recurrence, PFO closure provides marginal additional benefit in certain patients with a risk of side effects. Contemporary evidence-based risk scoring systems combined with echocardiography findings may be used together to better risk stratify patients and suitability for medical aviation recertification. Rengel AC, Gericke C. Embolic ischemic cortical stroke in a young flight instructor with a small patent foramen ovale. Aerosp Med Hum Perform. 2024; 95(10):784–787.

Impact of long-term white matter hyperintensity changes on mobility and dexterity.

White matter hyperintensities (WMH), a common feature of cerebral small vessel disease, are related to worse clinical outcomes after stroke. We assessed the impact of white matter hyperintensity changes over 1 year after minor stroke on change in mobility and dexterity, including differences between the dominant and non-dominant hands and objective in-person assessment versus patient-reported experience. We recruited participants with lacunar or minor cortical ischaemic stroke, performed medical and cognitive assessments and brain MRI at presentation and at 1 year. At both time points, we used the timed-up and go test and the 9-hole peg test to assess mobility and dexterity. At 1 year, participants completed the Stroke Impact Scale. We ran two linear mixed models to assess change in timed-up and go and 9-hole peg test, adjusted for age, sex, stroke severity (National Institutes of Health Stroke Scale), dependency (modified Rankin Score), vascular risk factor score, white matter hyperintensity volume (as % intracranial volume) and additionally for 9-hole peg test: Montreal cognitive assessment, hand (dominant/non-dominant), National Adult Reading Test (premorbid IQ), index lesion side. We performed ordinal logistic regression, corrected for age and sex, to assess relations between timed-up and go and Stroke Impact Scale mobility, and 9-hole peg test and Stroke Impact Scale hand function. We included 229 participants, mean age 65.9 (standard deviation = 11.13); 66% male. 215/229 attended 1-year follow-up. Over 1 year, timed-up and go time increased with aging (standardized β [standardized 95% Confidence Interval]: 0.124[0.011, 0.238]), increasing National Institutes of Health Stroke Scale (0.106[0.032, 0.180]), increasing modified Rankin Score (0.152[0.073, 0.231]) and increasing white matter hyperintensity volume (0.176[0.061, 0.291]). Men were faster than women (-0.306[0.011, 0.238]). Over 1 year, slower 9-hole peg test was related to use of non-dominant hand (0.290[0.155, 0.424]), aging (0.102[0.012, 0.192]), male sex (0.182[0.008, 0.356]), increasing National Institutes of Health Stroke Scale (0.160 [0.094, 0.226]), increasing modified Rankin Score (0.100[0.032, 0.169]), decreasing Montreal cognitive assessment score (-0.090[-0.167, -0.014]) and increasing white matter hyperintensity volume (0.104[0.015, 0.193]). One year post-stroke, Stroke Impact Scale mobility worsened per second increase on timed-up and go, odds ratio 0.67 [95% confidence interval 0.60, 0.75]. Stroke Impact Scale hand function worsened per second increase on the 9-hole peg test for the dominant hand (odds ratio 0.79 [0.71, 0.86]) and for the non-dominant hand (odds ratio 0.88 [0.83, 0.93]). Decline in mobility and dexterity is associated with white matter hyperintensity volume increase, independently of stroke severity. Mobility and dexterity declined more gradually for stable and regressing white matter hyperintensity volume. Dominant and non-dominant hands might be affected differently. In-person measures of dexterity and mobility are associated with self-reported experience 1-year post-stroke.

Integrating single-cell and spatially resolved transcriptomic strategies to survey the astrocyte response to stroke in male mice

Astrocytes, a type of glial cell in the central nervous system (CNS), adopt diverse states in response to injury that are influenced by their location relative to the insult. Here, we describe a platform for spatially resolved, single-cell transcriptomics and proteomics, called tDISCO (tissue-digital microfluidic isolation of single cells for -Omics). We use tDISCO alongside two high-throughput platforms for spatial (Visium) and single-cell transcriptomics (10X Chromium) to examine the heterogeneity of the astrocyte response to a cortical ischemic stroke in male mice. We show that integration of Visium and 10X Chromium datasets infers two astrocyte populations, proximal or distal to the injury site, while tDISCO determines the spatial boundaries and molecular profiles that define these populations. We find that proximal astrocytes show differences in lipid shuttling, with enriched expression of Apoe and Fabp5. Our datasets provide a resource for understanding the roles of astrocytes in stroke and showcase the utility of tDISCO for hypothesis-driven, spatially resolved single-cell experiments.

MANF protein expression is upregulated in immune cells in the ischemic human brain and systemic recombinant MANF delivery in rat ischemic stroke model demonstrates anti-inflammatory effects

Mesencephalic astrocyte-derived neurotrophic factor (MANF) has cytoprotective effects on various injuries, including cerebral ischemia, and it can promote recovery even when delivered intracranially several days after ischemic stroke. In the uninjured rodent brain, MANF protein is expressed almost exclusively in neurons, but post-ischemic MANF expression has not been characterized. We aimed to investigate how endogenous cerebral MANF protein expression evolves in infarcted human brains and rodent ischemic stroke models. During infarct progression, the cerebral MANF expression pattern both in human and rat brains shifted drastically from neurons to expression in inflammatory cells. Intense MANF immunoreactivity took place in phagocytic microglia/macrophages in the ischemic territory, peaking at two weeks post-stroke in human and one-week post-stroke in rat ischemic cortex. Using double immunofluorescence and mice lacking MANF gene and protein from neuronal stem cells, neurons, astrocytes, and oligodendrocytes, we verified that MANF expression was induced in microglia/macrophage cells in the ischemic hemisphere. Embarking on the drastic expression transition towards inflammatory cells and the impact of blood-borne inflammation in stroke, we hypothesized that exogenously delivered MANF protein can modulate tissue recovery processes. In an attempt to enhance recovery, we designed a set of proof-of-concept studies using systemic delivery of recombinant MANF in a rat model of cortical ischemic stroke. Intranasal recombinant MANF treatment decreased infarct volume and reduced the severity of neurological deficits. Intravenous recombinant MANF treatment decreased the levels of pro-inflammatory cytokines and increased the levels of anti-inflammatory cytokine IL-10 in the infarcted cortex one-day post-stroke. In conclusion, MANF protein expression is induced in activated microglia/macrophage cells in infarcted human and rodent brains, and this could implicate MANF’s involvement in the regulation of post-stroke inflammation in patients and experimental animals. Moreover, systemic delivery of recombinant MANF shows promising immunomodulatory effects and therapeutic potential in experimental ischemic stroke.

One right can make a left: sentence processing in the right hemisphere after perinatal stroke.

When brain regions that are critical for a cognitive function in adulthood are irreversibly damaged at birth, what patterns of plasticity support the successful development of that function in an alternative location? Here we investigate the consistency of language organization in the right hemisphere (RH) after a left hemisphere (LH) perinatal stroke. We analyzed fMRI data collected during an auditory sentence comprehension task on 14 people with large cortical LH perinatal arterial ischemic strokes (left hemisphere perinatal stroke (LHPS) participants) and 11 healthy sibling controls using a "top voxel" approach that allowed us to compare the same number of active voxels across each participant and in each hemisphere for controls. We found (1) LHPS participants consistently recruited the same RH areas that were a mirror-image of typical LH areas, and (2) the RH areas recruited in LHPS participants aligned better with the strongly activated LH areas of the typically developed brains of control participants (when flipped images were compared) than the weakly activated RH areas. Our findings suggest that the successful development of language processing in the RH after a LH perinatal stroke may in part depend on recruiting an arrangement of frontotemporal areas reflective of the typical dominant LH.

Resting-state functional connectivity in a non-human primate model of cortical ischemic stroke in area F1

BackgroundThe application of functional MRI to non-human primates after stroke has not yet been undertaken. This is the first study to explore the functional connectivity changes in non-human primate models during acute stages after stroke onset. MethodsNineteen healthy male cynomolgus monkeys (4–5 years) were used in this study. The photothrombosis model was employed to induce focal ischemic stroke in F1 area in the monkey's left hemisphere. T1-weighted structural images and resting-state functional magnetic resonance imaging (rs-fMRI) of all subjects were obtained using a 3.0 Tesla MRI system on the third day following stroke. Based on the D99 atlas, the structural and functional changes of bilateral F1 areas in monkeys were analyzed using region of interest (ROI)-based functional connectivity (FC). The bilateral F1 areas were selected as the seed regions due to their crucial role in motor control and their potential to unveil the comprehensive functional reorganization of the motor system at a whole-brain level following stroke. ResultsIschemic lesions were observed after the stroke, with larger lesion volumes associated with poorer neurological dysfunction. Compared with baseline condition, left area F1 demonstrated decreased FC with the left cerebellum, left ventral pons and left 5_(PEa). When the ROI was located in the right area F1, ischemic monkeys showed decreased FC in left ventral pons, left cerebellum, left primary visual cortex and left 5_(PEa), accompanied by increased FC in the right orbitofrontal cortex. Importantly, the degree of altered FC between left area F1 and left cerebellum was associated with upper limb tone. ConclusionsThese results provide valuable insights into the early-stage functional connectivity changes in the F1 areas of monkeys under ischemic conditions, highlighting the potential involvement of specific brain regions in the pathophysiology of ischemic injury.

Cerebrovascular Reactivity in Patients With Small Vessel Disease: A Cross-Sectional Study.

Cerebrovascular reactivity (CVR) is inversely related to white matter hyperintensity severity, a marker of cerebral small vessel disease (SVD). Less is known about the relationship between CVR and other SVD imaging features or cognition. We aimed to investigate these cross-sectional relationships. Between 2018 and 2021 in Edinburgh, we recruited patients presenting with lacunar or cortical ischemic stroke, whom we characterized for SVD features. We measured CVR in subcortical gray matter, normal-appearing white matter, and white matter hyperintensity using 3T magnetic resonance imaging. We assessed cognition using Montreal Cognitive Assessment. Statistical analyses included linear regression models with CVR as outcome, adjusted for age, sex, and vascular risk factors. We reported regression coefficients with 95% CIs. Of 208 patients, 182 had processable CVR data sets (median age, 68.2 years; 68% men). Although the strength of association depended on tissue type, lower CVR in normal-appearing tissues and white matter hyperintensity was associated with larger white matter hyperintensity volume (BNAWM=-0.0073 [95% CI, -0.0133 to -0.0014] %/mm Hg per 10-fold increase in percentage intracranial volume), more lacunes (BNAWM=-0.00129 [95% CI, -0.00215 to -0.00043] %/mm Hg per lacune), more microbleeds (BNAWM=-0.00083 [95% CI, -0.00130 to -0.00036] %/mm Hg per microbleed), higher deep atrophy score (BNAWM=-0.00218 [95% CI, -0.00417 to -0.00020] %/mm Hg per score point increase), higher perivascular space score (BNAWM=-0.0034 [95% CI, -0.0066 to -0.0002] %/mm Hg per score point increase in basal ganglia), and higher SVD score (BNAWM=-0.0048 [95% CI, -0.0075 to -0.0021] %/mm Hg per score point increase). Lower CVR in normal-appearing tissues was related to lower Montreal Cognitive Assessment without reaching convention statistical significance (BNAWM=0.00065 [95% CI, -0.00007 to 0.00137] %/mm Hg per score point increase). Lower CVR in patients with SVD was related to more severe SVD burden and worse cognition in this cross-sectional analysis. Longitudinal analysis will help determine whether lower CVR predicts worsening SVD severity or vice versa. URL: https://www.isrctn.com; Unique identifier: ISRCTN12113543.

Astrocyte-neuron lactate shuttle plays a pivotal role in sensory-based neuroprotection in a rat model of permanent middle cerebral artery occlusion

We have previously demonstrated protection from impending cortical ischemic stroke is achievable by sensory stimulation of the ischemic area in an adult rat model of permanent middle cerebral artery occlusion (pMCAo). We have further demonstrated that a major underpinning mechanism that is necessary for such protection is the system of collaterals among cerebral arteries that results in reperfusion of the MCA ischemic territory. However, since such collateral flow is weak, it may be necessary but not sufficient for protection and therefore we sought other complementary mechanisms that contribute to sensory-based protection. We hypothesized that astrocytes-neuron lactate shuttle (ANLS) activation could be another potential underpinning mechanism that complements collateral flow in the protection process. Supporting our hypothesis, using functional imaging, pharmacological treatments, and postmortem histology, we showed that ANLS played a pivotal role in sensory stimulation-based protection of cortex and therefore serves as the other supporting mechanism underpinning the protection process.

CORTICAL BLINDNESS DUE TO BILATERAL STROKES – A CASE REPORT OF ANTON SYNDROME

Background: Blindness (anopia) is a functional loss of vision, which could be due either to ophthalmological or neurological conditions. Blindness may be congenital or acquired. The main causes of blindness in adults are cataracts, uncorrected ametropia (myopia, astigmatism), glaucoma, macular dystrophy, cortical ischemic strokes, etc. In less than 10% of the patients, the reason for cortical blindness is bilateral occipital strokes, one of them hemorrhagic. Case Description: In the current case report, we present a 75-year-old patient with complaints of headache and visual loss. The patient has a history of a left PCA (posterior cerebral artery) distal ischemic stroke. The CT scan reveals a hypodense cerebral lesion in the left medial occipital cortex and subcortex (lingual gyri and cuneus) and a hyperdense cerebral lesion in the right medial occipital cortex and subcortex (lingual gyri and cuneus). The neurological examination shows only bilateral visual loss without motor deficits. The patient has visual anosognosia and confabulation in the setting of obvious visual loss and cortical blindness(Anton-Babinski syndrome, also known as ABS or Anton syndrome). However, performing cerebellar tests (dysdiadochokinesis, finger-to-nose test, heel-to-shin test, cerebellar ataxia) was not done because of the visual loss. After being consulted by a neurologist and neurosurgeon with the preliminary diagnosis of brain hemorrhage, the patient was admitted to the Neurology Clinic of UMHAT D-r "Georgi Stranski", Pleven, Bulgaria. Conclusion: Occipital infarction must be considered in all cases with sudden onset of isolated visual loss. Early diagnosis and treatment of stroke reduce mortality and morbidity. The prognosis depends on the extension of the visual cortex damage.

Persistent neurological and cerebrovascular deficits following ischemic stroke in a transgenic mouse model of Alzheimer’s disease

AbstractBackgroundTissue nonspecific alkaline phosphatase (TNAP) is one of the most abundant enzymes in brain cerebral microvessels, although its function in human health and disease remains less clear. Our lab has demonstrated that the loss of TNAP activity in cerebral microvessels is linked to diminished blood‐brain barrier function and decreased cerebrovascular integrity in mouse models of sepsis, ischemic stroke, and Alzheimer’s disease (AD). While it is widely known that stroke and AD are comorbid, the relationship between existing AD and its impact on outcomes following ischemic stroke is less clear. The goal of this study was to assess the impact of a moderate cortical ischemic stroke on post‐stroke sensorimotor deficits and AD‐like neuropathology in a mouse model of AD. We hypothesized that post‐stroke loss of TNAP activity is accompanied by a persistent loss of cerebral blood flow (CBF), exacerbated sensorimotor deficits, elevated neuroinflammation, and increased beta‐amyloid deposition.MethodMale and female APPSwID/iNOS‐/‐ (CVN‐AD) mice, 10‐12 months old, were subjected to a cortical photothrombotic stroke (AD+PTS) or sham (AD+sham) surgery and euthanized at seven days post‐stroke. Daily neurological scores, corner test, and rotarod were performed to assess sensorimotor deficits. CBF was assessed by laser speckle contrast imaging (LSCI) prior to euthanasia. Saline‐perfused and 4% paraformaldehyde fixed tissue sections underwent histological staining to quantify infarct volume, cerebral microvessel TNAP activity, and microhemorrhages. Immunostaining assessed astrogliosis, via glial fibrillary acidic protein (GFAP), microgliosis, via Iba‐1, and beta‐amyloid deposition.ResultIschemic stroke impaired performance on the corner test (p=0.0054) and rotarod (p=0.0138) in PTS+AD compared to sham+AD mice. At seven days post‐stroke CBF was diminished (p<0.0001) while Iba‐1 immunolabeling revealed increased microgliosis in the ipsilateral cortex (p<0.0001) and ipsilateral hippocampal CA1 (p=0.0022) in PTS+AD compared to sham+AD mice. A preliminary quantification of TNAP activity in the non‐infarcted ipsilateral hemisphere revealed a trending decrease in PTS+AD mice. No sex differences were observed.ConclusionSensorimotor deficits and microgliosis were increased while CBF was decreased at seven days post‐stroke in PTS+AD compared to sham+AD mice. These and other indices will be compared with age‐matched wild‐type mice in ongoing experiments.

Distribution Pattern Analysis of Cortical Brain Infarcts on Diffusion-Weighted Magnetic Resonance Imaging: A Hypothesis-Generating Approach to the Burden of Silent Embolic Stroke.

Background In patients with covert cerebrovascular disease or proximal source of embolism, embolic silent brain infarction may precede major stroke events. Therefore, characterization of particularly cortical silent brain infarction is essential for identifying affected patients and commencing adequate secondary prevention. This study aimed to investigate differences in the distribution pattern of cortical ischemic stroke lesions to assess potential predilection sites of cortical silent brain infarction. Methods and Results We prospectively included all consecutive patients with stroke presenting from January 1 to December 31, 2018. Diffusion-weighted imaging lesions were used to generate voxel-based lesion maps and assigned to atlas-based cortical regions of interest in middle cerebral artery territories. Each region-of-interest lesion frequency was related to the respective region-of-interest volume to identify frequently affected and underrepresented cerebral cortex areas. Diffusion-weighted imaging data for voxel-based lesion maps were available in 334 out of 633 patients. Primary analysis revealed that small- (<0.24 cc) and medium-sized (0.24-2640 cc) lesions distributed predominantly along regions associated with sensorimotor or language function. Detailed analysis within middle cerebral artery territories showed an approximated frequency of missed cortical stroke lesions of up to 67% in the right and 69% in the left hemisphere. In particular, the frontal, temporal, and occipital cortices were underrepresented. Larger lesion size and areas associated with higher cortical function led to hospital admission. Conclusions Cortical brain infarcts in hospitalized patients are not dispersed equally but are predominantly located in brain structures associated with motor control and sensory and language function. Matching underrepresented cerebral cortex regions to symptoms not yet associated with stroke warrants further exploration.

Methamphetamine Use: A Narrative Review of Adverse Effects and Related Toxicities

Methamphetamine has been labeled "America's most dangerous drug" and has received significant public health attention. Stimulant addiction and tolerance are heavily documented in the literature; increasingly larger doses maintain euphoria in short time periods to withstand stimulant tolerance. Stimulant deaths are high in the United States and abroad. Between 2013 and 2019, deaths related to methamphetamine use quadrupled from 3,616 to 16,127. Methamphetamine use increased four-fold from 2015 to 2016. Due to this increase in methamphetamine use and its associated medical complications, the mortality rate associated with methamphetamine use has doubled over the past ten years. Cardiopulmonary symptoms include chest pain, palpitations, and shortness of breath. Methamphetamine-related myocardial infarction can also occur. Central nervous system symptoms include agitation, anxiety, delusions, hallucinations, and seizures. Methamphetamine-induced psychosis may unmask underlying psychiatric disorders. It can also cause cerebral vasculitis, which elicits cortical blindness and ischemic strokes. Methamphetamine-induced neurotoxicity in serotonergic systems is more diffuse, involving the striatum, hippocampus, septum, amygdala, and hypothalamus leading to mood changes, psychosis, and memory impairment. This narrative review will aim to highlight the adverse effects as well as the toxicity that can occur with methamphetamine use.

Neuroprotective Effects of Electrical Stimulation Following Ischemic Stroke in Non-Human Primates.

Brain stimulation has emerged as a novel therapy for ischemic stroke, a major cause of brain injury that often results in lifelong disability. Although past works in rodents have demonstrated protective effects of stimulation following stroke, few of these results have been replicated in humans due to the anatomical differences between rodent and human brains and a limited understanding of stimulation-induced network changes. Therefore, we combined electrophysiology and histology to study the neuroprotective mechanisms of electrical stimulation following cortical ischemic stroke in non-human primates. To produce controlled focal lesions, we used the photothrombotic method to induce targeted vasculature damage in the sensorimotor cortices of two macaques while collecting electrocorticography (ECoG) signals bilaterally. In another two monkeys, we followed the same lesioning procedures and applied repeated electrical stimulation via an ECoG electrode adjacent to the lesion. We studied the protective effects of stimulation on neural dynamics using ECoG signal power and coherence. In addition, we performed histological analysis to evaluate the differences in lesion volume. In comparison to controls, the ECoG signals showed decreased gamma power across the sensorimotor cortices in stimulated animals. Meanwhile, Nissl staining revealed smaller lesion volumes for the stimulated group, suggesting that electrical stimulation may exert neuroprotection by suppressing post-ischemic neural activity. With the similarity between NHP and human brains, this study paves the path for developing effective stimulation-based therapy for acute stroke in clinical studies.

Abstract TP219: ACE2L: A Novel Scoring Tool With High Sensitivity And Specificity In Predicting Atrial Fibrillation In Cryptogenic Stroke

Introduction/Background: Stroke is a leading cause of serious, long-term disability and death worldwide. Atrial fibrillation (AF) is the most common form of sustained cardiac arrhythmia, and is associated with a high risk of ischemic stroke and thromboembolism. Many cryptogenic strokes may be due to underlying, undetected paroxysmal AF. We performed a retrospective evaluation of patients with a history of ischemic stroke who were subsequently diagnosed with AF in order to develop a novel risk score calculator to help guide management in patients with cryptogenic stroke. Methods: We evaluated patients with a history of ischemic stroke both with and without a subsequent diagnosis of AF. Patients with a pre-existing diagnosis of AF were excluded. 1 point was assigned for each of the following: (1) age &gt; 60; (2) cortical ischemic stroke; (3) embolic appearance on imaging; (4) p-wave terminal force &gt; 5000 μVms; (5) increased left atrial volume index; (6) lack of extracranial large vessel occlusion (LVO). Patients with ipsilateral extracranial LVO and patients with LVO &gt; 70% were excluded. Results: A total of 74 patients with a diagnosis of ischemic stroke were evaluated. Of these, 41 patients had a subsequent diagnosis of AF, and 33 patients did not. A score of 4 or higher correlated with a sensitivity of 86.8% (95% CI: 72.7%, 94.2%), specificity of 100% (95% CI 89.8%, 100%), PPV 100% (95% CI 89.6%, 100%), NPV 87.2% (95% CI 73.3%, 94.4%), negative likelihood ratio 0.13 (95% CI 5.8%, 29.8%), and accuracy 93.1% (95% CI 84.8%, 897%). Conclusions: The novel ACE2L scoring tool demonstrated high sensitivity and specificity in predicting atrial fibrillation in patients with ischemic stroke. This scoring tool utilizes factors readily accessible in the evaluation of acute stroke and is a simple tool that may be used to help guide further management. Future, prospective studies are needed to further validate this scoring tool.

Distinguishing transient from persistent tactile agnosia after partial anterior circulation infarcts – Behavioral and neuroimaging evidence for white matter disconnection

From a cohort of 36 patients presenting apperceptive tactile agnosia after first cortical ischemic stroke, 14 showed temporary impairment at admission. A previous multi-voxel analysis of the cortical lesions, using as explanatory variable the course of tactile object recognition performance over the recovery period of 9 months, partitioned the cohort into three subgroups. Of the 14 patients constituting two of the subgroups, 7 recovered from their impairment whereas 7 did not. These two subgroups could not be distinguished at admission. The primary aim of the present study is to present two assessments that can do so.The first assessment comprises a pattern of behavioral measures, determined via principal component analysis, encoded in three tests: picking small objects, macrogeometrical discrimination and tactile object recognition. The receiver operating characteristic curve derived from permutation of the behavioral test scores yielded an 80% probability of correct identification of the patient subgroup and an 8% probability for false identification. As done with the permuted scores, the pattern could predict the persistence of affliction of new stroke patients with tactile agnosia.The second predictive assessment extends our previous evaluation of cortical MRI lesion maps to include subcortical regions. Confirming our previous study, the lesions of the persistently impaired subgroup disrupted significantly the anterior arcuatus fasciculus and associated superior longitudinal fasciculus III in the ipsilesional hemisphere, impeding reciprocal information transfer between supramarginal gyrus and both the ventral premotor cortex and Brodmann area 44. Due to the importance of interhemispheric information transfer in tactile agnosia, we performed a supplementary analysis of tactile object recognition scores. It showed that haptic information transfer from the non-affected to the affected hands in the persistent cases partly restored function during the nine months, possibly following restoration of functional interhemispheric haptic information transfer at the border of posterior corpus callosum and splenium.In conclusion, the combined findings of the cortical lesion at subarea PFt of the inferior parietal lobule and the associated subcortical tract lesions permit almost perfect prediction of persistent impairment of tactile object recognition. The study substantiates the need for combined analysis of both cortical lesions and white matter tract disconnections.

Combination of Endothelin-1 (ET-1) and L-NAME to Induce Murine Focal Cortical Stroke with Persistent Sensorimotor Deficits.

The endothelin-1 (ET-1) model of stroke involves the stereotactic injection of the vasoconstrictor ET-1 to produce a focal ischemic injury. In rats, this model produces consistent deficits, in contrast to more variable results in mice. In this chapter, we describe a new method to induce a murine focal ischemic cortical stroke by injecting L-NAME, another potent vasoconstrictor , in combination with ET-1 into the sensorimotor cortex. This ET-1 /L-NAME stroke induction protocol produces consistent focal cortical infarcts and sensorimotor functional impairments in C57BL/6 mice.

Hemichorea in a patient with ipsilateral cortical infarction: a case report

BackgroundHemichorea is usually caused by contralateral deep structures of brain. It rarely results from acute cortical ischemic stroke and that caused by ipsilateral brain lesions is even rarer.Case presentationA 64-year-old female presented with acute obtuseness and left-sided hemichorea. She had a history of right frontal lobe surgery and radiotherapy due to brain metastasis from lung cancer 8 years ago. MRI revealed acute left frontal lobe infarction in addition to an old right frontal lobe lesion. 18FDG PET-CT showed hypometabolism in the left frontal lobe and hypermetabolism in the right basal ganglia region and central sulcus. The choreatic movement remitted after antipsychotic treatment.ConclusionThe mechanism of hemichorea after ipsilateral cortical infarction is poorly understood. We assume both previous contralateral brain lesion and recent ipsilateral ischemic stroke contributed to the strange manifestation in this case.

Devil is in the detail, subtle signs of posterior reversible encephalopathy syndrome

A 33-year-old woman presented to the hospital with convulsive seizure and hypertensive crisis. As differential diagnosis cortical venous thrombosis, ischaemic or haemorrhagic stroke, space occupying lesion, Posterior Reversible Encephalopathy Syndrome (PRES) and epileptic syndrome were considered. Antiepileptic and antihypertensives drugs were used as initial clinical management.