Ischemic Stroke with Comorbid Cancer Has Specific miRNA-mRNA Networks in Blood That Vary by Ischemic Stroke Mechanism.

OBJECTIVE: Approximately half of ischemic strokes (IS) in cancer patients are cryptogenic, with many presumed cardioembolic. We evaluated whether there were specific miRNA and mRNA transcriptome architectures in peripheral blood of IS patients with and without comorbid cancer, and between cardioembolic versus noncardioembolic IS etiologies in comorbid cancer. METHODS: We studied patients with cancer and IS (CS; n = 42), stroke only (SO; n = 41), and cancer only (n = 28), and vascular risk factor-matched controls (n = 30). mRNA-Seq and miRNA-Seq data, analyzed with linear regression models, identified differentially expressed genes in CS versus SO and in cardioembolic versus noncardioembolic CS, and miRNA-mRNA regulatory pairs. Network-level analyses identified stroke etiology-specific responses in CS. RESULTS: A total of 2,085 mRNAs and 31 miRNAs were differentially expressed between CS and SO. In CS, 122 and 35 miRNA-mRNA regulatory pairs, and 5 and 3 coexpressed gene modules, were associated with cardioembolic and noncardioembolic CS, respectively. Complement, growth factor, and immune/inflammatory pathways showed differences between IS etiologies in CS. A 15-gene biomarker panel assembled from a derivation cohort (n = 50) correctly classified 81% of CS and 71% of SO participants in a validation cohort (n = 33). Another 15-gene panel correctly identified etiologies for 13 of 13 CS-cardioembolic and 11 of 11 CS-noncardioembolic participants upon cross-validation; 11 of 16 CS-cryptogenic participants were predicted cardioembolic. INTERPRETATION: We discovered unique mRNA and miRNA transcriptome architecture in CS and SO, and in CS with different IS etiologies. Cardioembolic and noncardioembolic etiologies in CS showed unique coexpression networks and potential master regulators. These may help distinguish CS from SO and identify IS etiology in cryptogenic CS patients. ANN NEUROL 2024;96:565-581.

Cerebral amyloid angiopathy and the immune system.

Cerebral amyloid angiopathy (CAA) is characterized by the accumulation of amyloid protein in the walls of cerebral blood vessels. This deposition of amyloid causes damage to the cerebral vasculature, resulting in blood-brain barrier disruption, cerebral hemorrhage, cognitive decline, and dementia. The role of the immune system in CAA is complex and not fully understood. While the immune system has a clear role in the rare inflammatory variants of CAA (CAA related inflammation and Abeta related angiitis), the more common variants of CAA also have immune system involvement. In a protective role, immune cells may facilitate the clearance of beta-amyloid from the cerebral vasculature. The immune system can also contribute to CAA pathology, promoting vascular injury, blood-brain barrier breakdown, inflammation, and progression of CAA. In this review, we summarize the role of the immune system in CAA, including the potential of immune based treatment strategies to slow vascular disease in CAA and associated cognitive impairment, white matter disease progression, and reduce the risk of cerebral hemorrhage. HIGHLIGHTS: The immune system has a role in cerebral amyloid angiopathy (CAA) which is summarized in this review. There is an inflammatory response to beta-amyloid that may contribute to brain injury and cognitive impairment. Immune cells may facilitate the clearance of beta-amyloid from the cerebral vasculature. Improved understanding of the immune system in CAA may afford novel treatment to improve outcomes in patients with CAA.

Quantifying cerebral microbleeds using quantitative susceptibility mapping from magnetization-prepared rapid gradient-echo.

T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE) is commonly included in brain studies for structural imaging using magnitude images; however, its phase images can provide an opportunity to assess microbleed burden using quantitative susceptibility mapping (QSM). This potential application for MPRAGE-based QSM was evaluated using in vivo and simulated measurements. Possible factors affecting image quality were also explored. Detection sensitivity was evaluated against standard multiecho gradient echo (MEGE) QSM using 3-T in vivo data of 15 subjects with a combined total of 108 confirmed microbleeds. The two methods were compared based on the microbleed size and susceptibility measurements. In addition, simulations explored the detection sensitivity of MPRAGE-QSM at different representative magnetic field strengths and echo times using microbleeds of different size, susceptibility, and location. Results showed that in vivo microbleeds appeared to be smaller (× 0.54) and of higher mean susceptibility (× 1.9) on MPRAGE-QSM than on MEGE-QSM, but total susceptibility estimates were in closer agreement (slope: 0.97, r2: 0.94), and detection sensitivity was comparable. In simulations, QSM at 1.5 T had a low contrast-to-noise ratio that obscured the detection of many microbleeds. Signal-to-noise ratio (SNR) levels at 3 T and above resulted in better contrast and increased detection. The detection rates for microbleeds of minimum one-voxel diameter and 0.4-ppm susceptibility were 0.55, 0.80, and 0.88 at SNR levels of 1.5, 3, and 7 T, respectively. Size and total susceptibility estimates were more consistent than mean susceptibility estimates, which showed size-dependent underestimation. MPRAGE-QSM provides an opportunity to detect and quantify the size and susceptibility of microbleeds of at least one-voxel diameter at B0 of 3 T or higher with no additional time cost, when standard T2*-weighted images are not available or have inadequate spatial resolution. The total susceptibility measure is more robust against sequence variations and might allow combining data from different protocols.

The whole day matters after stroke: Study protocol for a randomized controlled trial investigating the effect of a 'sit less, move more, sleep better' program early after stroke.

BACKGROUND: Movement-related behaviours, including prolonged sedentary behaviour, physical inactivity, and poor sleep, are associated with worse functional outcomes poststroke. Addressing these co-dependent behaviours early after stroke may help to optimize recovery and improve overall quality of life for individuals with stroke. OBJECTIVE: This study aims to determine the feasibility and effect of a 'sit less, move more, sleep better' program early after stroke on functional mobility and global disability outcomes, while also exploring imaging and behavioural markers that may influence walking recovery. METHODS: The study is an assessor-blinded, single-center, parallel-group, randomized controlled trial to be completed within 24 months from July 12, 2023 to June 30, 2025. We will enroll 50 patients with acute ischemic stroke within 7 days from symptom onset, aged 18 years or older, and with ongoing walking goals. Demographic and stroke characteristics, including stroke risk factors, neuroimaging, and acute stroke treatments, will be determined and documented. All participants will wear an accelerometer for one week at three different time-points (baseline, 6, and 12 weeks) to assess movement-related behaviours. Following randomization, participants in the intervention arm will receive a 'sit less, move more, sleep better' program for up to 1 hour/day, 5 days/week, for 6 weeks to enhance self-efficacy for change. Participants in the control arm will receive usual inpatient and early supported stroke discharge care. The feasibility outcomes will include reach (enrolled/eligible), retention (completed/enrolled), adverse events, and program adherence. Other outcomes at 6 and 12 weeks include the modified Rankin Scale, Timed-Up and Go, movement-related behaviours, walking endurance, gait speed, cognition, stroke severity and quality of life. Mixed-effects models will assess changes in outcomes over time. Compositional associations between movement-related behaviours and outcomes will consider covariates such as imaging markers. DISCUSSION: Adopting a whole-day approach to poststroke rehabilitation will provide valuable insights into the relationship between optimizing movement-related behaviours early after stroke and their impact on functional outcomes. Through exploring person-specific behavioural and imaging markers, this study may inform precision rehabilitation strategies, and guide clinical decision making for more tailored interventions. TRIAL REGISTRATION: Clinical Trial registration (ClinicalTrials.gov Identifier: NCT05753761, March 3, 2023).

Emotional dysmetria after cerebellar-pontine stroke: a case report.

INTRODUCTION: Pseudobulbar affect, or emotional dysregulation, commonly occurs following stroke. However, it is frequently missed in cases involving the cerebellum, resulting in a lack of treatment, which can directly impact stroke rehabilitation. CASE PRESENTATION: A 63-year-old Caucasian female with no history of mood disorders presented with gait instability, dysarthria, and right sided hemiplegia, secondary to cerebellar and pontine ischemic stroke from a basilar occlusion. She underwent endovascular therapy and her deficits gradually improved. However during recovery she began to develop uncontrollable tearfulness while retaining insight that her emotional expression was contextually inappropriate. She was treated with a selective serotonin reuptake inhibitor with reported improvements in her emotional regulation at one year follow up. CONCLUSION: This case highlights cerebellar injury as a potential cause of poorly regulated emotions, or an emotional dysmetria. The recognition of this disorder in patients with cerebellar or pontine strokes is critical, as untreated pseudobulbar affect can impact future stroke rehabilitation.

Sex Differences in Thrombin Generation in Patients with Acute Ischemic Stroke.

Sex differences in stroke exist, including variation in stroke risk and outcome. Differences in thrombin generation may contribute to this variation between females and males. To examine this, we assessed sex differences in thrombin generation between females and males with acute ischemic stroke and the relationship to blood cell gene expression. In 97 patients with acute ischemic stroke, thrombin generation was measured by thrombin generation assay. Blood cell gene expression was measured by microarray. Differences in thrombin generation between sexes were identified and the relationship to blood cell gene expression examined. Genes associated with sex differences in thrombin generation were analyzed by functional pathway analysis. Females and males had similar overall capacity to generate thrombin. The peak thrombin generated in females was 468.8 nM (SD 91.6), comparable to males (479.3nM;SD 90.8; p = 0.58). Lag time, time to peak thrombin, and endogenous thrombin potential were also similar between females and males. While overall thrombin generation was comparable between females and males with stroke, differences in genes that promote this thrombin generation exist. Females with high peak thrombin had an increase in genes that promote thrombosis, and platelet activation. In contrast, males with high peak thrombin had a decrease in genes involved in thrombus degradation. Females and males with acute ischemic stroke have similar capacity to generate thrombin, however, differences may exist in how this thrombin generation is achieved, with females having increased thrombin signaling, and platelet activation, and males having decreased thrombus degradation. This suggests regulatory differences in thrombosis may exist between females and males that may contribute to sex differences in stroke.

Choice of Oral Anticoagulant: Outcomes in Atrial Fibrillation Patients Post-Stroke Despite Direct Oral Anticoagulant Use.

Background: For patients with atrial fibrillation who have an ischemic stroke or transient ischemic attack (TIA) despite taking direct oral anticoagulants (DOACs), the optimal strategy for ongoing anticoagulation is unknown. Methods: Using provincial administrative databases in Alberta, Canada, we compared anticoagulant use before/after the breakthrough stroke/TIA and assessed recurrence of stroke/TIA or bleeding, with consideration of medication adherence. Adherence was defined as the proportion of days covered (PDC) being ≥ 80%. Results: Among 985 patients, the median age was 80 years (interquartile range 13), with a mean CHADS2 score of 1.7± 1 prior to the index event. Patients were followed for a median of 643 days (interquartile range 836). Following the index stroke/TIA event, 623 patients (63%) filled a prescription for the same DOAC regimen, 83 (8%) filled a prescription for a different dose, 155 (16%) switched DOAC agents, 51 (5%) switched to warfarin, and 73 (7%) filled no oral anticoagulant prescription. Patients who kept the same regimen more commonly had TIA index events (59%); patients who changed dose or drug more often had stroke index events (55%-78%). During follow-up, 135 (14%) had stroke/TIA recurrence, and 46 (5%) had bleeding; rates of each did not differ between prescribing patterns. Post-index event, the proportion of patients with a proportion of days covered ≥ 80% improved from 55% to 80%. Conclusions: Although most maintained the same DOAC regimen after stroke/TIA, rates of recurrent stroke/TIA and bleeding were similar across prescribing patterns. Stroke/TIA severity may have influenced prescribing practices. DOAC prescription adherence improved poststroke/TIA and signals an opportunity for optimization in patients with atrial fibrillation.

Contexte: Chez les patients atteints de fibrillation auriculaire qui subissent un accident vasculaire cérébral (AVC) ischémique ou un accident ischémique transitoire (AIT) malgré la prise d'anticoagulants oraux directe (AOD), la stratégie optimale pour la poursuite de l'anticoagulation est inconnue. Méthodologie: À partir des bases de données administratives provinciales en Alberta, au Canada, nous avons comparé l'utilisation d'anticoagulants avant/après l'AVC/AIT survenu pendant l'anticoagulothérapie et avons évalué la récurrence d'un AVC/AIT ou d'un saignement, en tenant compte de l'adhésion au traitement médicamenteux. L'adhésion a été définie comme une proportion de jours couverts (PJC) de 80 % ou plus. Résultats: Chez 985 patients, l'âge médian était de 80 ans (écart interquartile de 13) et le score CHADS2 moyen, de 1,7 ± 1 avant l'événement de référence. Les patients ont été suivis pendant une médiane de 643 jours (écart interquartile de 836). Après l'AVC/AIT de référence, 623 patients (63 %) ont fait exécuter une ordonnance du même schéma d'AOD, 83 (8 %) ont fait exécuter une ordonnance d'une dose différente, 155 (16 %) sont passés à d'autres AOD, 51 (5 %) sont passés à la warfarine et 73 (7 %) n'ont fait exécuter aucune ordonnance d'anticoagulant oral. Chez les patients qui ont continué à recevoir le même schéma, la plupart (59 %) avaient eu un AIT comme événement de référence; chez les patients qui ont changé de dose ou de médicament, la plupart (55 à 78 %) avaient eu un AVC comme événement de référence. Durant le suivi, 135 (14 %) ont connu un AVC/AIT récurrent et 46 (5 %) ont présenté un saignement; les taux de chaque manifestation ont été similaires pour les différents schémas de prescription. Après l'événement de référence, le pourcentage de patients ayant une PJC ≥ 80 % a augmenté, passant de 55 à 80 %. Conclusions: Malgré le maintien du même schéma d'AOD chez la plupart des patients après l'AVC/AIT, les taux d'AVC/AIT récurrent et de saignement ont été similaires avec tous les schémas de prescription. La gravité d'un AVC/AIT pourrait avoir influencé les pratiques de prescription. L'adhésion aux AOD prescrits s'est améliorée après un AVC/AIT et témoigne d'une possibilité d'optimisation chez les patients atteints de fibrillation auriculaire.

Suspension culture improves iPSC expansion and pluripotency phenotype.

BACKGROUND: Induced pluripotent stem cells (iPSCs) offer potential to revolutionize regenerative medicine as a renewable source for islets, dopaminergic neurons, retinal cells, and cardiomyocytes. However, translation of these regenerative cell therapies requires cost-efficient mass manufacturing of high-quality human iPSCs. This study presents an improved three-dimensional Vertical-Wheel® bioreactor (3D suspension) cell expansion protocol with comparison to a two-dimensional (2D planar) protocol. METHODS: Sendai virus transfection of human peripheral blood mononuclear cells was used to establish mycoplasma and virus free iPSC lines without common genetic duplications or deletions. iPSCs were then expanded under 2D planar and 3D suspension culture conditions. We comparatively evaluated cell expansion capacity, genetic integrity, pluripotency phenotype, and in vitro and in vivo pluripotency potential of iPSCs. RESULTS: Expansion of iPSCs using Vertical-Wheel® bioreactors achieved 93.8-fold (IQR 30.2) growth compared to 19.1 (IQR 4.0) in 2D (p < 0.0022), the largest expansion potential reported to date over 5 days. 0.5 L Vertical-Wheel® bioreactors achieved similar expansion and further reduced iPSC production cost. 3D suspension expanded cells had increased proliferation, measured as Ki67+ expression using flow cytometry (3D: 69.4% [IQR 5.5%] vs. 2D: 57.4% [IQR 10.9%], p = 0.0022), and had a higher frequency of pluripotency marker (Oct4+Nanog+Sox2+) expression (3D: 94.3 [IQR 1.4] vs. 2D: 52.5% [IQR 5.6], p = 0.0079). q-PCR genetic analysis demonstrated a lack of duplications or deletions at the 8 most commonly mutated regions within iPSC lines after long-term passaging (> 25). 2D-cultured cells displayed a primed pluripotency phenotype, which transitioned to naïve after 3D-culture. Both 2D and 3D cells were capable of trilineage differentiation and following teratoma, 2D-expanded cells generated predominantly solid teratomas, while 3D-expanded cells produced more mature and predominantly cystic teratomas with lower Ki67+ expression within teratomas (3D: 16.7% [IQR 3.2%] vs.. 2D: 45.3% [IQR 3.0%], p = 0.002) in keeping with a naïve phenotype. CONCLUSION: This study demonstrates nearly 100-fold iPSC expansion over 5-days using our 3D suspension culture protocol in Vertical-Wheel® bioreactors, the largest cell growth reported to date. 3D expanded cells showed enhanced in vitro and in vivo pluripotency phenotype that may support more efficient scale-up strategies and safer clinical implementation.

Risk of hemorrhagic transformation with early use of direct oral anticoagulants after acute ischemic stroke: A pooled analysis of prospective studies and randomized trials.

INTRODUCTION: Precise risk of hemorrhagic transformation (HT) in acute ischemic stroke (AIS) remains unknown, leading to delays in anticoagulation initiation for secondary stroke prevention. We sought to assess the rate of HT associated with direct oral anticoagulant (DOAC) initiation within and beyond 48 h post-AIS. METHODS: A pooled analysis of DOAC initiation within 14 days of AIS or transient ischemic attack (TIA) was conducted with six studies (four prospective open label treatment, blinded outcome studies and two randomized trials; NCT02295826 and NCT02283294). The primary endpoint was incident radiographic HT on follow-up imaging (days 7-30). Secondary endpoints included symptomatic HT, new parenchymal hemorrhage, recurrent ischemic events, extracranial hemorrhage, study period mortality, and follow-up modified Rankin Scale score. The results were reported as odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI). RESULTS: We evaluated 509 patients; median infarct volume was 1.5 (0.1-7.8) ml, and median National Institutes of Health Stroke Scale was 2 (0-3). Incident radiographic HT was seen on follow-up scan in 34 (6.8%) patients. DOAC initiation within 48 h from index event was not associated with incident HT (adjusted OR 0.67, [0.30-1.50] P = 0.32). No patients developed symptomatic HT. Conversely, 31 (6.1%) patients developed recurrent ischemic events, 64% of which occurred within 14 days. Initiating a DOAC within 48 h of onset was associated with similar recurrent ischemic event rates compared with those in which treatment was delayed (HR: 0.42, [0.17-1.008] P = 0.052). In contrast to HT, recurrent ischemic events were associated with poor functional outcomes (OR = 6.8, [2.84-16.24], p < 0.001). CONCLUSIONS: In this pooled analysis, initiation of DOAC within 48 h post-stroke was not associated with increased incident risk of HT, and none developed symptomatic HT. The analysis was underpowered to determine the effect of early DOAC use upon recurrent ischemic events.

Monocyte, neutrophil, and whole blood transcriptome dynamics following ischemic stroke.

BACKGROUND: After ischemic stroke (IS), peripheral leukocytes infiltrate the damaged region and modulate the response to injury. Peripheral blood cells display distinctive gene expression signatures post-IS and these transcriptional programs reflect changes in immune responses to IS. Dissecting the temporal dynamics of gene expression after IS improves our understanding of immune and clotting responses at the molecular and cellular level that are involved in acute brain injury and may assist with time-targeted, cell-specific therapy. METHODS: The transcriptomic profiles from peripheral monocytes, neutrophils, and whole blood from 38 ischemic stroke patients and 18 controls were analyzed with RNA-seq as a function of time and etiology after stroke. Differential expression analyses were performed at 0-24 h, 24-48 h, and >48 h following stroke. RESULTS: Unique patterns of temporal gene expression and pathways were distinguished for monocytes, neutrophils, and whole blood with enrichment of interleukin signaling pathways for different time points and stroke etiologies. Compared to control subjects, gene expression was generally upregulated in neutrophils and generally downregulated in monocytes over all times for cardioembolic, large vessel, and small vessel strokes. Self-organizing maps identified gene clusters with similar trajectories of gene expression over time for different stroke causes and sample types. Weighted Gene Co-expression Network Analyses identified modules of co-expressed genes that significantly varied with time after stroke and included hub genes of immunoglobulin genes in whole blood. CONCLUSIONS: Altogether, the identified genes and pathways are critical for understanding how the immune and clotting systems change over time after stroke. This study identifies potential time- and cell-specific biomarkers and treatment targets.

microRNA as a therapeutic for ischemic stroke.

microRNA (miRNA) are important regulators of gene expression. miRNA have the potential as a treatment to modulate genes, pathways and cells involved in ischemic stroke. In this review, we specifically present miRNA in stroke as a treatment to decrease thrombosis, reduce blood brain barrier (BBB) disruption and hemorrhagic transformation (HT), modulate inflammation, and modify angiogenesis. miRNA as a treatment for stroke is an emerging area with evidence from animal studies demonstrating its potential. While no miRNA is currently approved for human use, several have shown promise in clinical trials to treat medical conditions, such as miR-122 for hepatitis C. The role of miRNA as a treatment for specific applications in ischemic stroke is presented including a discussion of the benefits and barriers of miRNA as a treatment, and directions for future advancement.

Early peripheral blood gene expression associated with good and poor 90-day ischemic stroke outcomes.

BACKGROUND: This study identified early immune gene responses in peripheral blood associated with 90-day ischemic stroke (IS) outcomes. METHODS: Peripheral blood samples from the CLEAR trial IS patients at ≤ 3 h, 5 h, and 24 h after stroke were compared to vascular risk factor matched controls. Whole-transcriptome analyses identified genes and networks associated with 90-day IS outcome assessed using the modified Rankin Scale (mRS) and the NIH Stroke Scale (NIHSS). RESULTS: The expression of 467, 526, and 571 genes measured at ≤ 3, 5 and 24 h after IS, respectively, were associated with poor 90-day mRS outcome (mRS ≥ 3), while 49, 100 and 35 genes at ≤ 3, 5 and 24 h after IS were associated with good mRS 90-day outcome (mRS ≤ 2). Poor outcomes were associated with up-regulated genes or pathways such as IL-6, IL-7, IL-1, STAT3, S100A12, acute phase response, P38/MAPK, FGF, TGFA, MMP9, NF-kB, Toll-like receptor, iNOS, and PI3K/AKT. There were 94 probe sets shared for poor outcomes vs. controls at all three time-points that correlated with 90-day mRS; 13 probe sets were shared for good outcomes vs. controls at all three time-points; and 46 probe sets were shared for poor vs. good outcomes at all three time-points that correlated with 90-day mRS. Weighted Gene Co-Expression Network Analysis (WGCNA) revealed modules significantly associated with 90-day outcome for mRS and NIHSS. Poor outcome modules were enriched with up-regulated neutrophil genes and with down-regulated T cell, B cell and monocyte-specific genes; and good outcome modules were associated with erythroblasts and megakaryocytes. Finally, genes identified by genome-wide association studies (GWAS) to contain significant stroke risk loci or loci associated with stroke outcome including ATP2B, GRK5, SH3PXD2A, CENPQ, HOXC4, HDAC9, BNC2, PTPN11, PIK3CG, CDK6, and PDE4DIP were significantly differentially expressed as a function of stroke outcome in the current study. CONCLUSIONS: This study suggests the immune response after stroke may impact functional outcomes and that some of the early post-stroke gene expression markers associated with outcome could be useful for predicting outcomes and could be targets for improving outcomes.

How to Define Fast and Slow Progressors in Any-Type Occlusion Acute Ischemic Stroke.

The variable rate of infarct progression in acute ischemic stroke as assessed by various thresholds excludes a substantial proportion of patients due to time or core constraints. We evaluated 106 patients with any-type occlusion to compare these thresholds and assessed performance of hypoperfusion index (HI) for fast and slow rate of infarct progression. Seven (12.5%) were classified fast progressors and 23 (46%), 25 (50%), 12 (24%), and 33 (66%) slow progressors using different core and time criteria. In comparison, HI categorized 100% (n = 106) of cohort with optimal cutoff 0.5 for any-type occlusion (slow progressors: HI ≤ 0.5), sensitivity/specificity 100%/91%, AUC 0.94, and indicative of eligibility for reperfusion and clinical outcomes (median 90-day modified Rankin Scale; 2 for HI ≤ 0.5 versus 5). Estimation of progressors by HI seems comprehensive but needs external validation.

Timing of Anticoagulation after Acute Ischemic Stroke in Patients with Atrial Fibrillation.

Patients with atrial fibrillation (AF) and ischemic stroke are at high risk for stroke recurrence. Early anticoagulation may reduce the risk of recurrent events but is usually avoided due to the risk of hemorrhagic transformation (HT). Current guidelines are based on empiric expert opinion. The assumed risk of HT is based on historical data from an older generation of anticoagulants. The direct oral anticoagulants (DOACs) have demonstrated lower risk of intracranial hemorrhage compared to older anticoagulants. However, the optimal timing of DOAC initiation after AF-related ischemic stroke has remained an area of clinical equipoise, as the pivotal phase III trials did not include patients in the early period after ischemic stroke. Multiple prospective studies and a few smaller randomized controlled trials evaluating the safety and efficacy of early versus delayed DOAC initiation have been completed. These studies have reported promising results of early DOAC initiation after acute ischemic stroke. However, a standardized documentation of HT rates on follow-up imaging with objective assessment criteria is missing from most of these studies. Larger randomized trials of early versus delayed DOAC are ongoing. A literature review was performed using keywords and Medical Subject Headings in MEDLINE/PubMed and Google Scholar databases. For each relevant paper, the bibliography was scrutinized for other relevant articles and journals. In this article, we review the risk of recurrent ischemic stroke and HT in patients with AF, pathophysiology, classification, predictors, natural history, and outcomes of HT and discuss the studies of early anticoagulation after AF-related ischemic stroke.

Association of Thrombin Generation With Leukocyte Inflammatory Profile in Patients With Acute Ischemic Stroke.

BACKGROUND AND OBJECTIVES: Thrombosis is central to the pathogenesis of acute ischemic stroke, with higher thrombin generation being associated with increased stroke risk. The immune system may contribute to thrombin generation in stroke and thus may offer novel strategies for stroke prevention. This study addresses the research question regarding the relationship of thrombin generation to leukocyte gene expression in patients with acute ischemic stroke. METHODS: We isolated RNA from whole blood and examined the relationship to thrombin generation capacity in patients with acute ischemic stroke. Due to its effects on thrombin generation, patients on anticoagulants were excluded from the study. The relationship of gene expression with peak thrombin was evaluated by analysis of covariance across peak thrombin quartiles adjusted for sex and age. RESULTS: In 97 patients with acute ischemic stroke, peak thrombin was variable, ranging from 252.0 to 752.4 nM. Increased peak thrombin was associated with differences in thromboinflammatory leukocyte gene expression, including a decrease in ADAM metallopeptidase with thrombospondin type 1 motif 13 and an increase in nuclear factor κB (NF-κB)-activating protein, protein disulfide isomerase family A member 5, and tissue factor pathway inhibitor 2. Pathways associated with peak thrombin included interleukin 6 signaling, thrombin signaling, and NF-κB signaling. A linear discriminant analysis model summarizing the immune activation associated with peak thrombin in a first cohort of stroke could distinguish patients with low peak thrombin from high peak thrombin in a second cohort of 112 patients with acute ischemic stroke. DISCUSSION: The identified genes and pathways support a role of the immune system contributing to thrombus formation in patients with stroke. These may have relevance to antithrombotic strategies for stroke prevention.

Interleukin-6 Predicts Carotid Plaque Severity, Vulnerability, and Progression.

BACKGROUND: IL-6 (interleukin-6) has important roles in atherosclerosis pathophysiology. To determine if anti-IL-6 therapy warrants evaluation as an adjuvant stroke prevention strategy in patients with carotid atherosclerosis, we tested whether circulating IL-6 levels predict carotid plaque severity, vulnerability, and progression in the prospective population-based CHS (Cardiovascular Health Study). METHODS: Duplex carotid ultrasound was performed at baseline and 5 years. Baseline plaque severity was scored 0 to 5 based on North American Symptomatic Carotid Endarterectomy Trial grade of stenosis. Plaque vulnerability at baseline was the presence of markedly irregular, ulcerated, or echolucent plaques. Plaque progression at 5 years was a ≥1 point increase in stenosis severity. The relationship of baseline plasma IL-6 levels with plaque characteristics was modeled using multivariable linear (severity) or logistic (vulnerability and progression) regression. Risk factors of atherosclerosis were included as independent variables. Stepwise backward elimination was used with P>0.05 for variable removal. To assess model stability, we computed the E-value or minimum strength of association (odds ratio scale) that unmeasured confounders must have with log IL-6 and the outcome to suppress the association. We performed internal validation with 100 bootstrap samples. RESULTS: There were 4334 participants with complete data (58.9% women, mean age: 72.7±5.1 years), including 1267 (29.2%) with vulnerable plaque and 1474 (34.0%) with plaque progression. Log IL-6 predicted plaque severity (ß=0.09, P=1.3×10-3), vulnerability (OR, 1.21 [95% CI, 1.05-1.40]; P=7.4×10-3, E-value=1.71), and progression (OR, 1.44 [95% CI, 1.23-1.69], P=9.1×10-6, E-value 2.24). In participants with >50% predicted probability of progression, mean log IL-6 was 0.54 corresponding to 2.0 pg/mL. Dichotomizing IL-6 levels did not affect the performance of prediction models. CONCLUSIONS: Circulating IL-6 predicts carotid plaque severity, vulnerability, and progression. The 2.0 pg/mL cutoff could facilitate the selection of individuals that would benefit from anti-IL-6 drugs for stroke prevention.

Progression of cerebral white matter hyperintensities is related to leucocyte gene expression.

Cerebral white matter hyperintensities are an important contributor to ageing brain pathology. Progression in white matter hyperintensity volume is associated with cognitive decline and gait impairment. Understanding the factors associated with white matter hyperintensity progression provides insight into pathogenesis and may identify novel treatment targets to improve cognitive health. We postulated that the immune system interaction with cerebral vessels and tissue may be associated with disease progression, and thus evaluated the relationship of blood leucocyte gene expression to progression of cerebral white matter hyperintensities. A brain MRI was obtained at baseline in 166 patients assessed for a cognitive complaint, and then repeated at regular intervals over a median of 5.9 years (interquartile range 3.5-8.2 years). White matter hyperintensity volumes were measured by semi-automated segmentation and percentage change in white matter hyperintensity per year calculated. A venous blood sample obtained at baseline was used to measure whole-genome expression by RNA sequencing. The relationship between change in white matter hyperintensity volumes over time and baseline leucocyte gene expression was analysed. The mean age was 77.8 (SD 7.5) years and 60.2% of participants were female. The median white matter hyperintensity volume was 13.4 ml (SD 17.4 ml). The mean change in white matter hyperintensity volume was 12% per year. Patients were divided in quartiles by percentage change in white matter hyperintensity volume, which was: -3.5% per year in quartile 1, 7.4% per year in quartile 2, 11.7% in quartile 3 and 33.6% per year in quartile 4. There were 148 genes associated with changing white matter hyperintensity volumes over time (P < 0.05 r > |0.2|). Genes and pathways identified have roles in endothelial dysfunction, extracellular matrix remodelling, altered remyelination, inflammation and response to ischaemia. ADAM8, CFD, EPHB4, FPR2, Wnt-B-catenin, focal adhesion kinase and SIGLEC1 were among the identified genes. The progression of white matter hyperintensity volumes over time is associated with genes involved in endothelial dysfunction, extracellular matrix remodelling, altered remyelination, inflammation and response to ischaemia. Further studies are needed to evaluate the role of peripheral inflammation in relation to rate of white matter hyperintensity progression and the contribution to cognitive decline.

Cerebrovascular Reactivity Across the Entire Brain in Cerebral Amyloid Angiopathy.

BACKGROUND AND OBJECTIVES: Reduced cerebrovascular reactivity is proposed to be a feature of cerebral amyloid angiopathy (CAA) but has not been measured directly. Employing a global vasodilatory stimulus (hypercapnia), this study assessed the relationships between cerebrovascular reactivity and MRI markers of CAA and cognitive function. METHODS: In a cross-sectional study, individuals with probable CAA, mild cognitive impairment, or dementia due to Alzheimer disease and healthy controls underwent neuropsychological testing and an MRI that included a 5% carbon dioxide challenge. Cerebrovascular reactivity was compared across groups controlling for age, sex, and the presence of hypertension, and its associations with MRI markers of CAA in participants with CAA and with cognition across all participants were determined using multivariable linear regression adjusting for group, age, sex, education, and the presence of hypertension. RESULTS: Cerebrovascular reactivity data (mean ± SD) were available for 26 participants with CAA (9 female; 74.4 ± 7.7 years), 19 participants with mild cognitive impairment (5 female; 72.1 ± 8.5 years), 12 participants with dementia due to Alzheimer disease (4 female; 69.4 ± 6.6 years), and 39 healthy controls (30 female; 68.8 ± 5.4 years). Gray and whiter matter reactivity averaged across the entire brain was lower in participants with CAA and Alzheimer disease dementia compared to healthy controls, with a predominantly posterior distribution of lower reactivity in both groups. Higher white matter hyperintensity volume was associated with lower white matter reactivity (standardized coefficient [ß], 95% CI -0.48, -0.90 to -0.01). Higher gray matter reactivity was associated with better global cognitive function (ß 0.19, 0.03-0.36), memory (ß 0.21, 0.07-0.36), executive function (ß 0.20, 0.02-0.39), and processing speed (ß 0.27, 0.10-0.45) and higher white matter reactivity was associated with higher memory (ß 0.22, 0.08-0.36) and processing speed (ß 0.23, 0.06-0.40). CONCLUSIONS: Reduced cerebrovascular reactivity is a core feature of CAA and its assessment may provide an additional biomarker for disease severity and cognitive impairment.