Plasminogen activator inhibitor-1 serum levels in frontotemporal lobar degeneration.

Plasminogen activator inhibitor-1 (PAI-1) impedes brain plasmin synthesis. Reduced plasmin activity facilitates cumulation of amyloid beta (Aß) in Alzheimer's disease (AD). Since plasmin also regulates the synaptic activity, it is possible that altered PAI-1 is present in other neurodegenerative disorders. We investigated whether PAI-1 and its counter-regulatory tissue plasminogen activator (tPA) are altered in serum of patients with dementia due to frontotemporal lobar degeneration (FTLD). Thirty five FTLD patients (21 in mild cognitive impairment stage (MCI) and 14 in dementia stage) and 10 cognitively healthy controls were recruited. Serum tPA and PAI-1 protein levels were measured by anova. Correlation between biochemical and demographic data were explored by measuring Pearson correlation coefficient. Serum PAI-1 levels were elevated in the FTLD dementia group as compared to FTLD MCI and controls. tPA serum levels and PAI-1/tPA ratio did not significantly differ among groups. There was a negative correlation between PAI-1 serum levels and disease severity measured by MMSE score. No correlations of tPA serum levels and PAI-1/tPA ratio with MMSE were found. Increased PAI-1 serum levels may serve as a marker of dementia in FTLD, suggesting that, besides Aß pathway, the plasmin system may affect cognition through synaptic activity.

Lack of Interactions Between Alteplase/Tenecteplase and the Adenosine A1R/A3R Agonist AST-004.

BACKGROUND: AST-004, a small molecule agonist of the adenosine A1 and A3 receptors, is a potential cerebroprotectant for patients with acute stroke and is currently in clinical trials. Drug-drug interactions are critically important to assess in the context of acute stroke care. Lytic therapy with tPA (tissue-type plasminogen activator)-induced plasmin formation (alteplase) is the only available pharmacotherapy for acute stroke. Consequently, it is imperative to evaluate potential interactions between AST-004 and tPAs such as alteplase and tenecteplase. METHODS: The interactions between AST-004 and tPAs were evaluated in 3 ways in preparation for AST-004 phase II trials. First, the metabolic stability of AST-004 was determined in the presence of alteplase and plasmin. Second, the potential for AST-004 to influence the thrombolytic efficacy of alteplase and tenecteplase was evaluated with an in vitro assay system utilizing a fluorogenic substrate of plasmin. Finally, the potential for AST-004 to influence the thrombolytic efficacy of alteplase was also determined with an in vitro thrombolysis assay of human blood thrombi. RESULTS: Neither alteplase nor plasmin affected the stability of AST-004 in vitro. In 2 different in vitro systems, AST-004 had no effect on the ability of alteplase or tenecteplase to generate plasmin, and AST-004 had no effect on the thrombolytic efficacy of alteplase to lyse blood clots in human blood. CONCLUSIONS: These studies indicate that there will be no interactions between AST-004 and tPAs such as alteplase or tenecteplase in patients with stroke undergoing thrombolytic therapy.

Angioedema After Use of Recombinant Tissue-Type Plasminogen Activators in Stroke.

Angioedema without concomitant urticaria is a well-known complication of treatment with the recombinant tissue-type plasminogen activator (r-tPA) alteplase and its genetically modified variant tenecteplase. It is potentially lethal when causing airway obstruction and can require intubation. The latest guideline for the early management of patients with acute ischemic stroke from the American Heart Association/American Stroke Association advises to treat this complication initially by interfering with the histamine pathway. This article aims to clarify the pathophysiological mechanism of r-tPA-induced angioedema and provides several arguments that this condition is primarily bradykinin-mediated and hence should be treated initially by intervening with the bradykinin pathway. Second, other-less frequently reported-adverse symptoms after r-tPA therapy and their proposed pathophysiological mechanisms leading to specific treatment are described. This manuscript describes the need for an update of the section "3.5 IV alteplase" from the American Heart Association/American Stroke Association guideline to treat this r-tPA-induced angioedema adequately and prevent potentially fatal outcomes.

Endovascular Thrombectomy Alone for Large Vessel Occlusion: A Cost-Effectiveness Evaluation Based on Meta-Analyses.

BACKGROUND: The benefit of intravenous thrombolysis with alteplase before endovascular thrombectomy (EVT) for acute ischemic stroke due to large vessel occlusion remains debated. In this study, we analyzed the cost-effectiveness of EVT alone versus intravenous alteplase before EVT in patients directly admitted to EVT-capable stroke centers from the Dutch health care payer perspective. METHODS: A decision analysis was performed using a Markov model with 15-year simulated follow-up to estimate total costs, quality-adjusted life years, and an incremental cost-effectiveness ratio of intravenous alteplase before EVT compared with EVT alone. A hypothetical cohort of 10 000 patients with large vessel occlusion aged 70 years was run in Monte Carlo simulation. Functional outcome of each treatment was derived from pooled results of 6 randomized controlled trials (RCTs). Uncertainty was assessed by probabilistic analyses, scenario analyses, and 1-way sensitivity analyses. RESULTS: Using functional outcomes obtained from 6 RCTs (intention-to-treat population), intravenous alteplase before EVT resulted in 0.05 quality-adjusted life years gained at an additional $2817 compared with EVT alone, resulting in the incremental cost-effectiveness ratio of $62 287. Probabilistic analyses showed that intravenous alteplase before EVT had a probability of 45% and 54%, respectively, of being cost-effective at the $52 500 and $84 000 thresholds. Restricting functional outcomes from our post hoc modified as-treated analysis of 6 RCTs (scenario 1), European RCTs (scenario 2), or a Dutch RCT (scenario 3), intravenous alteplase before EVT was cost-effective in 64%, 81%, and 50% of simulations at the $52 500 threshold, and 79%, 91%, and 67% of simulations at the $84 000 threshold. CONCLUSIONS: Intravenous alteplase before EVT was not cost-effective in patients with large vessel occlusion in the Netherlands at the $52 500 threshold but possibly cost-effective at the $84 000 threshold. Variable functional outcomes at 3 months based on different trial populations affected the cost-effectiveness of intravenous alteplase before EVT.

Safety and Efficacy of Reteplase Versus Alteplase for Acute Ischemic Stroke: A Phase 2 Randomized Controlled Trial.

BACKGROUND: Reteplase is a more affordable new-generation thrombolytic with a prolonged half-life. We aimed to determine the safety dose range of reteplase for patients with acute ischemic stroke within 4.5 hours of onset. METHODS: This is a multicenter, prospective, randomized controlled, open-label, blinded-end point phase 2 clinical trial. Patients with acute ischemic stroke aged between 18 and 80 years who were eligible for standard intravenous thrombolysis were enrolled from 17 centers in China and randomly assigned (1:1:1) to receive intravenous reteplase 12+12 mg, intravenous reteplase 18+18 mg, or intravenous alteplase 0.9 mg/kg. The primary safety outcome was symptomatic intracranial hemorrhage (SITS definition) within 36 hours. The primary efficacy outcome was the proportion of patients with the National Institutes of Health Stroke Scale score of no more than 1 or a decrease of at least 4 points from the baseline at 14 days after thrombolysis. RESULTS: Between August 2019 and May 2021, 180 patients were randomly assigned to reteplase 12+12 mg (n=61), reteplase 18+18 mg (n=67), or alteplase (n=52). Four patients did not receive the study agent. Symptomatic intracranial hemorrhage occurred in 3 of 60 (5.0%) in the reteplase 12+12 mg group, 1 of 66 (1.5%) in the reteplase 18+18 mg group, and 1 of 50 (2.0%) in the alteplase group (P=0.53). The primary efficacy outcome in the modified intention-to-treat population occurred in 45 of 60 (75.0%) in the reteplase 12+12 mg group (odds ratio, 0.85 [95% CI, 0.35-2.06]), 48 of 66 (72.7%) in the reteplase 18+18 mg group (odds ratio, 0.75 [95% CI, 0.32-1.78]), and 39 of 50 (78.0%) in alteplase group. CONCLUSIONS: Reteplase was well tolerated in patients with acute ischemic stroke within 4.5 hours of onset in China with a similar efficacy profile to alteplase. The efficacy and appropriate dosage of reteplase for patients with acute ischemic stroke need prospective validation. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04028518.

Dual Antiplatelet Versus Alteplase for Early Neurologic Deterioration in Minor Stroke With Versus Without Large Vessel Occlusion: Prespecified Post Hoc Analysis of the ARAMIS Trial.

BACKGROUND: Dual antiplatelet therapy (DAPT) was noninferior to alteplase in minor nondisabling strokes in the ARAMIS trial (Antiplatelet Versus R-tPA for Acute Mild Ischemic Stroke); however, early neurological deterioration (END) associated with vessel stenosis may benefit from DAPT. We investigated whether the efficacy of DAPT was greater than alteplase in minor strokes with no large vessel occlusion (LVO). METHODS: This study was a prespecified post hoc analysis of the ARAMIS trial and included patients with responsible vessel examination in the as-treated analysis set of the ARAMIS trial who were divided into LVO group and non-LVO group. In each group, patients were further classified into DAPT and intravenous alteplase treatments. Primary outcome was END at 24 hours defined as more than or equal to 4-point National Institutes of Health Stroke Scale score increase compared with baseline, and safety outcomes were symptomatic intracerebral hemorrhage and bleeding events during study. The primary analysis was estimated with a risk difference calculated by a generalized linear model including adjusted different baseline characteristics between treatments. RESULTS: Of 723 patients from the ARAMIS trial, 480 patients were included: 36 were categorized into LVO group and 444 into non-LVO group, of whom 20 patients had END. Compared with intravenous alteplase, a lower proportion of END was found after DAPT treatment in the non-LVO group (adjusted risk difference, -4.8% [95% CI, -6.9% to -2.6%]; P<0.001), but not in the LVO group (adjusted risk difference, 2.3% [95% CI, -17.6% to 22.3%]; P=0.82). The interaction was marginally significant between groups (P=0.06). In the non-LVO group, a lower proportion of bleeding events was found after DAPT treatment than intravenous alteplase (adjusted risk difference, -6.4% [95% CI, -8.9% to -3.9%]; P<0.001). Other safety outcomes were similar between the 2 treatments. CONCLUSIONS: Among minor nondisabling acute ischemic stroke without LVO, DAPT may be superior to intravenous alteplase regarding preventing END with a better safety profile. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03661411.

Fibrinolytic treatment using recombinant tissue-type plasminogen activator (rt-PA) for staphylococcal infective endocarditis.

Infective endocarditis (IE) is a severe illness characterized by vegetation of bacterial thrombosis. We hypothesized that adding recombinant tissue-type plasminogen activator (rt-PA) to antibiotics would contribute to good results in the treatment of IE. As an in vitro study, we injected labeled Staphylococcus aureus (S. aureus) and either rt-PA or PBS + plasminogen into a polydimethylsiloxane flow chamber with fibrin on a coverslip, and then performed immunofluorescent area assessment. As an in vivo experiment, IE model rats that had suffered mechanical damage in the aortic valve by catheter and revealed bacterial vegetation caused by S. aureus injection were treated with either a control, cefazolin (CEZ), rt-PA, or rt-PA + CEZ, for 7 days. Survival was assessed for 14 days after the appearance of vegetation, with daily monitoring of the vegetation by transthoracic echocardiography (TTE). The in vitro investigation showed that perfusion of rt-PA could detach S. aureus significantly more efficiently than PBS could. In the in vivo research, the rt-PA + CEZ group survived significantly longer than the other groups, and rt-PA + CEZ was more effective than CEZ in the dissolution of vegetation, as observed by TTE. In conclusion, adding rt-PA to antibiotic treatment could dissolve the vegetation component synergistically and improve the survival rate.

Catheter-Directed Thrombolysis for (Not Immediately) Threatened Acute Lower Limb Ischemia: Clinical Outcome and Efficacy.

OBJECTIVE: The objective of this study was to examine the short- and midterm outcomes of catheter-directed thrombolysis (CDT) for acute lower limb ischemia (ALI), classes Rutherford 1 and 2, with specific attention to functional outcome. METHODS: This retrospective study included patients with ALI treated with CDT from 2 vascular centers between May 2018 and April 2021. Cases were analyzed in groups according to the Rutherford (1 and 2) classification. The primary endpoint was functional outcome during follow-up, assessed by Rutherford's chronic limb ischemia classification. Functional outcomes over time were analyzed by generalized estimating equations. Kaplan-Meier analysis was used to estimate reintervention, amputation, survival, and reintervention-free survival rates. RESULTS: Two hundred cases were included (Rutherford 1, n = 51; Rutherford 2, n = 149). Total median treatment duration was 27 hours in the Rutherford 1 group and 39 hours in the Rutherford 2 group (P= 0.120). Initial clinical success was high (Rutherford 1, 82% vs Rutherford 2, 89%; P= 0.253). Complications were comparable between the 2 groups: major bleeding 8% vs 10% (P= 0.634), major amputation 4% vs 7% (P= 0.603), and mortality 6% vs 6% (P= 0.967). Median follow-up was 32 months (0-63 months). During follow-up, there was a high number of reinterventions (43%) and amputations (20%) in patients with Rutherford 1 limb ischemia, which was comparable to patients with Rutherford 2 limb ischemia. Fifty-six percent of the patients with Rutherford 1 limb ischemia reaching 2 years of follow-up were asymptomatic, 20% had mild and 16% had moderate to severe claudication. Initial clinical success following CDT and not immediately threatened ischemia at presentation are associated with improved functional outcomes during follow-up (P < 0.001 and P= 0.009, respectively). CONCLUSIONS: In our cohort, CDT was effective in reestablishing arterial flow for not immediately threatened ALI. Patients with Rutherford 1 limb ischemia who receive CDT had a more favorable functional outcome than patients with more severe limb ischemia (Rutherford 2). However, reinterventions were required frequently, and there was a substantial risk of complications. CLINICAL IMPACT: Acute lower limb ischemia (ALI) does not immediately jeopardize limb survival in patients with Rutherford 1 limb ischemia but can induce disabling claudication. In such patients, catheter-directed thrombolysis (CDT) is often performed to improve functional outcome. However, previous reports warned about the complications of CDT, and so far, mid- and long-term functional outcomes have not been reported. This study, in which a large cohort of patients with ALI was included, demonstrates a high technical success of CDT for not immediately threatened ALI with more favorable functional outcomes when compared with those with threatened limbs. Nevertheless, major complications pose a serious risk, and the need for reinterventions in the long term is high.

Ipsilateral orolingual angioedema following rhTNK-tPA administration for acute ischemic stroke.

Recombinant human tenecteplase tissue-type plasminogen activator (rhTNK-tPA), a genetically modified variant of conventional alteplase with longer half-life and higher fibrin specificity, has now emerged as a reasonable choice for thrombolytic treatment of acute ischemic stroke (AIS) in China. Orolingual angioedema is a rare but potentially life-threatening complication of intravenous thrombolysis. Currently, there is no documented evidence of orolingual angioedema occurring after thrombolysis with rhTNK-tPA. In this report, we present a unique case of a 75-year-old Chinese man who developed ipsilateral orolingual angioedema following the administration of rhTNK-tPA for AIS. Our case emphasizes the need for caution when using rhTNK-tPA due to its potential to induce ipsilateral orolingual angioedema.

Nationally Certified Stroke Centers Outperform Self-Attested Stroke Centers in the Florida Stroke Registry.

BACKGROUND: The Florida Stroke Act, signed into law in 2004, set criteria for Comprehensive Stroke Centers (CSC). For a set time period, Florida hospitals were permitted to either receive national certification (NC) or could self-attest (SA) as fulfilling CSC criteria. The aim of this project was to evaluate the quality of ischemic stroke care in NC versus SA stroke centers in Florida, using well-known, guideline-driven ischemic stroke outcome metrics. METHODS: A total of 37 CSCs (74% of Florida CSCs) in the Florida Stroke Registry from January 2013 through December 2018 were analyzed, including 19 SA CSCs and 18 NC (13 CSCs and 5 Thrombectomy-Capable Stroke Center). Hospital- and patient-level characteristics and stroke metrics were evaluated, adjusting for demographics, medical comorbidities, and stroke severity. RESULTS: A total of 78 424 acute ischemic stroke cases, 36 089 from SA CSCs and 42 335 from NC CSC/Thrombectomy-Capable Stroke Centers were analyzed. NC centers had older patients (73 [61-83] versus 71 [60-81]; P<0.001) with more severe strokes (median National Institutes of Health Stroke Scale score of 5 versus 4; P<0.001). NC had higher intravenous tissue-type plasminogen activator utilization (15% versus 13%; P<0.001), endovascular treatment (10% versus 7%; P<0.001) and faster median door-to-computed tomography (23 minutes [11-73] versus 31 [12-78]; P<0.001), door-to-needle (37 minutes [26-50] versus 45 [34-58]; P<0.001) and door-to-puncture times (77 minutes [50-113] versus 93 [62-140]; P<0.001). In adjusted analysis, patients arriving to NC hospitals by 3 hours were more likely to get intravenous tissue-type plasminogen activator in the 3- to 4.5-hour window (adjusted odds ratio, 1.87 [95% CI, 1.30-2.68]; P=0.001) and more likely to be treated with intravenous tissue-type plasminogen activator within 45 minutes (adjusted odds ratio, 1.61 [95% CI, 1.04-2.50]; P=0.04) compared with SA CSCs. CONCLUSIONS: Among Florida-Stroke Registry CSCs, acute ischemic stroke performance and treatment measures at NC centers are superior to SA CSCs. These findings have implications for stroke systems of care in Florida and support legislation updates requiring NC and removal of SA claims.

Neurovascular Inflammation and Complications of Thrombolysis Therapy in Stroke.

Intravenous thrombolysis via tPA (tissue-type plasminogen activator) is the only approved pharmacological treatment for acute ischemic stroke, but its benefits are limited by hemorrhagic transformation. Emerging evidence reveals that tPA swiftly mobilizes immune cells which extravasate into the brain parenchyma via the cerebral vasculature, augmenting neurovascular inflammation, and tissue injury. In this review, we summarize the pronounced alterations of immune cells induced by tPA in patients with stroke and experimental stroke models. We argue that neuroinflammation, triggered by ischemia-induced cell death and exacerbated by tPA, compromises neurovascular integrity and the microcirculation, leading to hemorrhagic transformation. Finally, we discuss current and future approaches to attenuate thrombolysis-associated hemorrhagic transformation via uncoupling immune cells from the neurovascular unit.

Improving Large Animal Ischemic Stroke Models for Translational Studies in the Era of Recanalization.

Recanalization therapy with endovascular procedures has led to significant advances in the treatment of acute ischemic stroke. Animal models have been the basis for enhancing the development of novel treatments and therapeutic modalities. However, previous translational failures led to an increasing consensus that large animals should be included to bridge the gap between rodent and human studies. In the era of large vessel recanalization, large animal ischemic stroke models should be optimized for preclinical and translational stroke studies. Here we highlight recent progress of reproducing ischemic and reperfusion mechanisms in large animal models of stroke through surgical and endovascular methods. The importance of optimizing large animal stroke modeling is suggested by evaluating new findings from clinical trials and preclinical experiments using large animals, such as adopting advanced imaging analysis and long-term functional evaluation. Furthermore, we also acknowledge the importance of adhering to the Stroke Treatment and Academic Roundtable recommendations and the "3 R" principles to improve the quality and validity of large animal experiments. Large animal models offer many translational benefits; however, more work is still needed to enhance studies using large animal model on acute ischemic stroke in the era of recanalization.

Socioeconomic Inequalities in Functional Outcome After Reperfusion-Treated Ischemic Stroke.

BACKGROUND: We aimed to investigate whether socioeconomic status (SES) was associated with functional outcome in patients with ischemic stroke treated with reperfusion therapy (intravenous thrombolysis and/or thrombectomy). METHODS: This nationwide cohort study included reperfusion-treated patients with ischemic stroke ≥18 years registered in the Danish Stroke Registry between 2015 and 2018. Functional outcome was determined by the modified Rankin Scale score 90 days after stroke. SES was defined by educational attainment, family income, and employment status before stroke. SES data were available from Statistics Denmark and linked on the individual level with data from the Danish Stroke Registry. Uni- and multivariable ordinal logistic regression was performed for each socioeconomic parameter individually (education, income, and employment) to estimate the common odds ratios (cORs) for lower 90-day modified Rankin Scale scores. RESULTS: A total of 5666 patients were included. Mean age was 68.7 years (95% CI, 68.3-69.0), and 38.4% were female. Low SES was associated with lower odds for achieving lower 90-day modified Rankin Scale score: Low versus high education, cOR, 0.69 (95% CI, 0.61-0.79), low versus high income, cOR, 0.59 (95% CI, 0.53-0.67), and unemployed versus employed, cOR, 0.70 (95% CI, 0.58-0.83). Inequalities were reduced after adjusting for age, sex, and immigrant status, except for unemployed versus employed patients, adjusted cOR, 0.66 (95% CI, 0.54-0.80). No statistically significant differences remained after adjusting for potentially mediating variables (eg, stroke severity, prestroke modified Rankin Scale, and smoking). CONCLUSIONS: Socioeconomic inequalities were observed in functional outcome after reperfusion treated ischemic stroke. In particular, prestroke unemployment was negatively associated with good functional outcome. A more adverse prognostic profile among patients with low SES appeared to explain the majority of these inequalities.

An antibody that targets cell-surface glucose-regulated protein-78 inhibits expression of inflammatory cytokines and plasminogen activator inhibitors by macrophages.

Glucose-regulated protein-78 (Grp78) is an endoplasmic reticulum chaperone, which is secreted by cells and associates with cell surfaces, where it functions as a receptor for activated α2 -macroglobulin (α2 M) and tissue-type plasminogen activator (tPA). In macrophages, α2 M and tPA also bind to the transmembrane receptor, LDL receptor-related protein-1 (LRP1), activating a cell-signaling receptor assembly that includes the NMDA receptor (NMDA-R) to suppress innate immunity. Herein, we demonstrate that an antibody targeting Grp78 (N88) inhibits NFκB activation and expression of proinflammatory cytokines in bone marrow-derived macrophages (BMDMs) treated with the toll-like receptor-4 (TLR4) ligand, lipopolysaccharide, or with agonists that activate TLR2, TLR7, or TLR9. Pharmacologic inhibition of the NMDA-R or deletion of the gene encoding LRP1 (Lrp1) in BMDMs neutralizes the activity of N88. The fibrinolysis protease inhibitor, plasminogen activator inhibitor-1 (PAI1), has been implicated in diverse diseases including metabolic syndrome, cardiovascular disease, and type 2 diabetes. Deletion of Lrp1 independently increased expression of PAI1 and PAI2 in BMDMs, as did treatment of wild-type BMDMs with TLR agonists. tPA, α2 M, and N88 inhibited expression of PAI1 and PAI2 in BMDMs treated with TLR-activating agents. Inhibiting Src family kinases blocked the ability of both N88 and tPA to function as anti-inflammatory agents, suggesting that the cell-signaling pathway activated by tPA and N88, downstream of LRP1 and the NMDA-R, may be equivalent. We conclude that targeting cell-surface Grp78 may be effective in suppressing innate immunity by a mechanism that requires LRP1 and the NMDA-R.

Antibody-mediated inhibition of tissue-type plasminogen activator binding to the low-density lipoprotein receptor-related protein 1 as a potential beneficial modulator for stroke therapy.

The acute ischemic stroke therapy of choice is the application of Alteplase, a drug containing the enzyme tissue-type plasminogen activator (tPa) which rapidly destabilizes blood clots. A central hallmark of stroke pathology is blood-brain barrier (BBB) breakdown associated with tight junction (TJ) protein degradation, which seems to be significantly more severe under therapeutic conditions. The exact mechanisms how tPa facilitates BBB breakdown are not entirely understood. There is evidence that an interaction with the lipoprotein receptor-related protein 1 (LRP1), allowing tPa transport across the BBB into the central nervous system, is necessary for this therapeutic side effect. Whether tPa-mediated disruption of BBB integrity is initiated directly on microvascular endothelial cells or other brain cell types is still elusive. In this study we could not observe any changes of barrier properties in microvascular endothelial cells after tPa incubation. However, we present evidence that tPa causes changes in microglial activation and BBB breakdown after LRP1-mediated transport across the BBB. Using a monoclonal antibody targeting the tPa binding sites of LRP1 decreased tPa transport across an endothelial barrier. Our results indicate that limiting tPa transport from the vascular system into the brain by coapplication of a LRP1-blocking monoclonal antibody might be a novel approach to minimize tPa-related BBB damage during acute stroke therapy.

tPA Mobilizes Immune Cells That Exacerbate Hemorrhagic Transformation in Stroke.

RATIONALE: Hemorrhagic complications represent a major limitation of intravenous thrombolysis using tPA (tissue-type plasminogen activator) in patients with ischemic stroke. The expression of tPA receptors on immune cells raises the question of what effects tPA exerts on these cells and whether these effects contribute to thrombolysis-related hemorrhagic transformation. OBJECTIVE: We aim to determine the impact of tPA on immune cells and investigate the association between observed immune alteration with hemorrhagic transformation in ischemic stroke patients and in a rat model of embolic stroke. METHODS AND RESULTS: Paired blood samples were collected before and 1 hour after tPA infusion from 71 patients with ischemic stroke. Control blood samples were collected from 27 ischemic stroke patients without tPA treatment. A rat embolic middle cerebral artery occlusion model was adopted to investigate the underlying mechanisms of hemorrhagic transformation. We report that tPA induces a swift surge of circulating neutrophils and T cells with profoundly altered molecular features in ischemic stroke patients and a rat model of focal embolic stroke. tPA exacerbates endothelial injury, increases adhesion and migration of neutrophils and T cells, which are associated with brain hemorrhage in rats subjected to embolic stroke. Genetic ablation of annexin A2 in neutrophils and T cells diminishes the effect of tPA on these cells. Decoupling the interaction between mobilized neutrophils/T cells and the neurovascular unit, achieved via a S1PR (sphingosine-1-phosphate receptor) 1 modulator RP101075 and a CCL2 (C-C motif chemokine ligand 2) synthesis inhibitor bindarit, which block lymphocyte egress and myeloid cell recruitment, respectively, attenuates hemorrhagic transformation and improves neurological function after tPA thrombolysis. CONCLUSIONS: Our findings suggest that immune invasion of the neurovascular unit represents a previously unrecognized mechanism underlying tPA-mediated brain hemorrhage, which can be overcome by precise immune modulation during thrombolytic therapy.

Perfusion deficits in thrombolysis-treated acute ischemic stroke patients with negative or positive diffusion-weighted imaging.

OBJECTIVE: Magnetic resonance imaging (MRI) and CT perfusion may provide diagnostic information for intravenous tissue-type plasminogen activator (IV t-PA) administration in acute ischemic stroke (AIS) patients. We aimed to compare the clinical features and perfusion deficits of diffusion weighted imaging (DWI)-negative and DWI-positive AIS patients. METHODS: This retrospective and observational study included thrombolysis-treated AIS patients undergoing multimodel CT imaging before treatment and DWI after treatment between 2021 and 2022. Two experienced neuroradiologists blindly and independently examined the images to identify perfusion deficits in AIS patients. The patients were divided into DWI-positive and DWI-negative groups based on visible hyperintense lesions on DWI. A modified Rankin scale (mRS) score of ≤ 2 indicated good functional outcomes at discharge. Sensitivity analysis was conducted to determine whether CT perfusion was an independent predictor of positive DWI imaging on follow-up. RESULTS: This study included 151 patients, of whom 35 (23.2%) patients were DWI-negative on follow-up. These DWI-negative patients were less likely to have a medical history of atrial fibrillation; they had lower triglyceride levels, a shorter admission time, lower National Institutes of Health Stroke Scale (NIHSS) scores after IV t-PA and lower mRS scores at discharge, and had better functional outcomes. A total of 37.1% of DWI-positive and 25.7% of DWI-negative patients had vascular stenosis (P = 0.215). A total of 47.4% of DWI-positive and 37.1% of DWI-negative patients had CT perfusion deficits (P = 0.284). A total of 73.5% of patients with normal CT perfusion had positive DWI, while 19.1% of patients with perfusion deficits had negative DWI. The sensitivity and specificity of NCCT were 14.8% and 97.1% (Kappa = 0.061, P = 0.074), CTP was 47.4% and 62.9% for predicting DWI lesion (Kappa = 0.069, P = 0.284). CONCLUSIONS: About 23.2% of AIS patients who received intravenous thrombolysis treatment did not have a relevant DWI-MRI lesion on follow-up. Over one-third of patients in the DWI-MRI negative group showed CT perfusion deficits, with a sensitivity of 47.4% for predicting DWI lesions in non-mechanical thrombectomy patients.

Effect of microbubbles on transcranial doppler ultrasound-assisted intracranial recombinant tissue-type plasminogen activator thrombolysis.

OBJECTIVES: The aim of this study was to evaluate the effect of microbubbles on the efficacy of transcranial doppler (TCD) ultrasound-assisted thrombolytic therapy of recombinant tissue-type plasminogen activator (rt-PA). METHODS: Male New Zealand white rabbits (n = 36) were randomly divided into an rt-PA group (n = 18) and an rt-PA plus microbubble group (n = 18). After the cerebral infarction model was constructed with autologous blood clots, rt-PA and rt-PA plus microbubble intervention were performed, respectively. The hemodynamic changes and infarct size of the two groups were recorded. In addition, the ELISA method was used to detect the level of nitric oxide (NO), superoxide dismutase (SOD), and malondialdehyde (MDA) in the brain tissue of the two-group graph model and high-sensitivity C-reactive protein (hs-CRP) in the serum. RESULTS: In the rt-PA group, the recanalization rate was 38.9% and the average infarct size was 11.8%. In the rt-PA plus microbubble group, the recanalization rate was 66.7% and the average infarct size was 8.2%. In addition, the average values for NO, SOD, MDA, and hs-CRP were 16.48 ± 5.39 µmol/L, 730.2 ± 9.86 U/mg, 0.92 ± 0.43 nmol/mg, and 8.56 ± 1.64 mg/L in the rt-PA group, respectively, and the average values were 9.18 ± 3.37 µmol/L, 426.2 ± 6.39 U/mg, 0.73 ± 0.44 nmol/mg, and 5.23 ± 0.94 mg/L in the rt-PA plus microbubble group, respectively. CONCLUSIONS: The addition of microbubbles enhanced the effects of TCD-assisted rrt-PA thrombolysis.

Parvalbumin interneuron-derived tissue-type plasminogen activator shapes perineuronal net structure.

BACKGROUND: Perineuronal nets (PNNs) are specialized extracellular matrix structures mainly found around fast-spiking parvalbumin (FS-PV) interneurons. In the adult, their degradation alters FS-PV-driven functions, such as brain plasticity and memory, and altered PNN structures have been found in neurodevelopmental and central nervous system disorders such as Alzheimer's disease, leading to interest in identifying targets able to modify or participate in PNN metabolism. The serine protease tissue-type plasminogen activator (tPA) plays multifaceted roles in brain pathophysiology. However, its cellular expression profile in the brain remains unclear and a possible role in matrix plasticity through PNN remodeling has never been investigated. RESULT: By combining a GFP reporter approach, immunohistology, electrophysiology, and single-cell RT-PCR, we discovered that cortical FS-PV interneurons are a source of tPA in vivo. We found that mice specifically lacking tPA in FS-PV interneurons display denser PNNs in the somatosensory cortex, suggesting a role for tPA from FS-PV interneurons in PNN remodeling. In vitro analyses in primary cultures of mouse interneurons also showed that tPA converts plasminogen into active plasmin, which in turn, directly degrades aggrecan, a major structural chondroitin sulfate proteoglycan (CSPG) in PNNs. CONCLUSIONS: We demonstrate that tPA released from FS-PV interneurons in the central nervous system reduces PNN density through CSPG degradation. The discovery of this tPA-dependent PNN remodeling opens interesting insights into the control of brain plasticity.

Intraventricular Hemorrhage Expansion in the CLEAR III Trial: A Post Hoc Exploratory Analysis.

BACKGROUND: The objective of this study was to evaluate factors associated with intraventricular hemorrhage (IVH) expansion and its association with long-term outcomes. METHODS: We performed a post hoc analysis of the international, multi-center CLEAR III trial (Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage) which enrolled IVH patients between September 1, 2009, and January 31, 2015. The exposure was IVH expansion, defined as >1 mL increase in volume between baseline and stability computed tomography scans, before treatment randomization. We assessed factors associated with IVH expansion and secondarily assessed the relationship of IVH expansion with clinical outcomes: composite of death or major disability (modified Rankin Scale score, >3), and mortality alone at 6 months. The relationship of IVH expansion on ventriculoperitoneal shunt placement was additionally explored. Multivariable logistic regression was used for all analyses. RESULTS: Of 500 IVH patients analyzed, the mean age was 59 (±11) years old, 44% were female and 135 (27%) had IVH expansion. In multivariable regression models, factors associated with IVH expansion were baseline parenchymal intracerebral hemorrhage (ICH) volume (adjusted odds ratio [OR], 1.04 per 1 mL increase [95% CI, 1.01-1.08]), presence of parenchymal hematoma expansion: >33% (adjusted OR, 6.63 [95% CI, 3.92-11.24]), time to stability head CT (adjusted OR, 0.71 per 1 hour increase [95% CI, 0.54-0.94]), and thalamic hematoma location (adjusted OR, 1.68 [95% CI, 1.01-2.79]) while additionally adjusting for age, sex, and race. In secondary analyses, IVH expansion was associated with higher odds of poor 6-month outcomes (adjusted OR, 1.84 [95% CI, 1.12-3.02]) but not mortality (OR, 1.40 [95% CI, 0.78-2.50]) after adjusting for baseline ICH volume, thalamic ICH location, age, anticoagulant use, Glasgow Coma Scale score, any withdrawal of care order, and treatment randomization arm. However, there were no relationships of IVH expansion on subsequent ventriculoperitoneal shunt placement (adjusted OR, 1.02 [95% CI, 0.58-1.80]) after adjusting for similar covariates. CONCLUSIONS: In a clinical trial cohort of patients with large IVH, acute hematoma characteristics, specifically larger parenchymal volume, hematoma expansion, and thalamic ICH location were associated with IVH expansion. Given that IVH expansion resulted in poor functional outcomes, exploration of treatment approaches to optimize hemostasis and prevent IVH expansion, particularly in patients with thalamic ICH, require further study. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT00784134.