Low-Dose Tissue Plasminogen Activator in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Platelet Membrane-Coated r-SAK Improves Thrombolytic Efficacy by Targeting Thrombus

Thrombolytic therapy is one of the most effective treatments for thrombus dissolution and recanalization of blocked vessels in thrombotic diseases. However, the application of the thrombolytic strategy has been limited due to unsatisfactory thrombolytic efficacy, relatively higher bleeding complications, and consequently restricted indications. Recombinant staphylokinase (r-SAK) is a third-generation thrombolytic agent produced by genetic engineering technology, which exhibits a better thrombolytic efficacy than urokinase and recombinant streptokinase. Inspired by the natural affinity of platelets in hemostasis and pathological thrombosis, we developed a platelet membrane (PM)-coated r-SAK (PM-r-SAK). Results from animal experiments and human in vitro studies showed that the PM-r-SAK had a thrombolytic efficacy equal to or better than its 4-fold dose of r-SAK. In a totally occluded rabbit femoral artery thrombosis model, the PM-r-SAK significantly shortened the initial recanalization time compared to the same dose and 4-fold dose of r-SAK. Regarding the recanalized vessels, the PM-r-SAK prolonged the time of reperfusion compared to the same dose and 4-fold dose of r-SAK, though the differences were not significant. An in vitro thrombolytic experiment demonstrated that the thrombolytic efficacy of PM-r-SAK could be inhibited by platelet-poor plasma from patients taking aspirin and ticagrelor. PM coating significantly improves the thrombolytic efficacy of r-SAK, which is related to the thrombus-targeting activity of the PM-r-SAK and can be inhibited by aspirin- and ticagrelor-treated plasma.

Parabiosis Discriminates the Circulating, Endothelial, and Parenchymal Contributions of Endogenous Tissue-Type Plasminogen Activator to Stroke

BACKGROUND

Intravenous injection of alteplase, a recombinant tPA (tissue-type plasminogen activator) as a thrombolytic agent has revolutionized ischemic stroke management. However, tPA is a more complex enzyme than expected, being for instance able to promote thrombolysis, but at the same time, also able to influence neuronal survival and to affect the integrity of the blood-brain barrier. Accordingly, the respective impact of endogenous tPA expressed/present in the brain parenchyma versus in the circulation during stroke remains debated.

METHODS

To address this issue, we used mice with constitutive deletion of tPA (tPANull [tPA-deficient mice]) or conditional deletion of endothelial tPA (VECad [vascular endothelial-Cadherin-Cre-recombinase]-Cre∆tPA). We also developed parabioses between tPANull and wild-type mice (tPAWT), anticipating that a tPAWT donor would restore levels of tPA to normal ones, in the circulation but not in the brain parenchyma of a tPANull recipient. Stroke outcomes were investigated by magnetic resonance imaging in a thrombo-embolic or a thrombotic stroke model, induced by local thrombin injection or FeCl3 application on the endothelium, respectively.

RESULTS

First, our data show that endothelial tPA, released into the circulation after stroke onset, plays an overall beneficial role following thrombo-embolic stroke. Accordingly, after 24 hours, tPANull/tPANull parabionts displayed less spontaneous recanalization and reperfusion and larger infarcts compared with tPAWT/tPAWT littermates. However, when associated to tPAWT littermates, tPANull mice had similar perfusion deficits, but less severe brain infarcts. In the thrombotic stroke model, homo- and hetero-typic parabionts did not differ in the extent of brain damages and did not differentially recanalize and reperfuse.

CONCLUSIONS

Together, our data reveal that during thromboembolic stroke, endogenous circulating tPA from endothelial cells sustains a spontaneous recanalization and reperfusion of the tissue, thus, limiting the extension of ischemic lesions. In this context, the impact of endogenous parenchymal tPA is limited.

Specific inhibition on PAI-1 reduces the dose of Alteplase for ischemic stroke treatment

Administration of recombinant tPA (rtPA, or trade name Alteplase®) is an FDA-approved therapy for acute ischemic stroke (AIS), but poses the risk of hemorrhagic complications. Recombinant tPA can be rapidly inactivated by the endogenous inhibitor, plasminogen activator inhibitor 1 (PAI-1). In this work, we study a novel treatment approach that combines a PAI-1 inhibitor, PAItrap4, with a reduced dose of rtPA to address the hemorrhagic concern of rtPA. PAItrap4 is a highly specific and very potent protein-based inhibitor of PAI-1, comprising of a variant of uPA serine protease domain, human serum albumin, and a cyclic RGD peptide. PAItrap4 efficiently targets and inhibits PAI-1 on activated platelets, and also possesses a long half-life in vivo. Our results demonstrate that PAItrap4 effectively counteracts the inhibitory effects of PAI-1 on rtPA, preserving rtPA activity based on amidolytic and clot lysis assays. In an in vivo murine stroke model, PAItrap4, together with low-dose rtPA, enhances the blood perfusion in the stroke-affected areas, reduces infarct size, and promotes neurological recovery in mice. Importantly, such treatment does not increase the amount of cerebral hemorrhage, thus reducing the risk of cerebral hemorrhage. In addition, PAItrap4 does not compromise the normal blood coagulation function in mice, demonstrating its safety as a therapeutic agent. These findings highlight this combination therapy as a promising alternative for the treatment of ischemic stroke, offering improved safety and efficacy.

Retrospective Evaluation of the Results of Low-Dose Intravenous Thrombolytic Therapy in Acute Ischemic Stroke

Objectives

This study aimed to investigate the clinical data of patients with acute ischemic stroke who received low-dose intravenous (IV) thrombolytic therapy (0.9 mg/kg; maximum 50 mg) for various reasons, compare the obtained results with those of patients who received standard-dose thrombolytic therapy, and discuss them in light of the literature.

Methods

Patients who received IV thrombolytic therapy within 4.5 h of symptom onset between January 2015 and June 2018 were retrospectively reviewed. Patients were divided into the low-dose group (0.9 mg/kg; max. 50 mg) and the standard-dose group (0.9 mg/kg; max 90 mg) according to the thrombolytic therapy dose, after which demographic data and clinical results were analyzed.

Results

A total of 109 patients receiving thrombolytic therapy (19 patients in the low-dose group and 90 patients in the standard-dose group) were included in the study. There was no significant difference between the two groups in terms of good outcome rates (47.4% vs. 52.2%). There was no statistically significant difference in terms of symptomatic and asymptomatic intracerebral hemorrhage rates.

Conclusion

Our study showed similar efficacy and safety for low-dose IV thrombolytic therapy compared with standard-dose IV thrombolytic therapy administered within 4.5 h of symptom onset in patients with acute ischemic stroke.

Can metformin use reduce the risk of stroke in diabetic patients? A systematic review and meta-analysis

BACKGROUND AND AIM

Stroke and cardiovascular diseases are major causes of death and disability, especially among diabetic patients. Some studies have shown that metformin has been effective in preventing cardiovascular diseases. In this study, we aim to evaluate the effect of metformin on stroke in type 2 diabetic patients.

METHODS

A comprehensive search was conducted in Medline, Embase, Scopus, and Web of Science databases from their inception till 1st July 2022. Randomized clinical trials (RCT) and cohort studies were included. Two independent researchers screened the records, extracted the data, and assessed the risk of bias and certainty of evidence. Findings were reported as risk ratio (RR) and 95% confidence interval (CI). All statistical analyses were performed using the STATA 17.0 software package.

RESULTS

Analysis of 21 included studies with 1,392,809 patients demonstrated that metformin monotherapy was effective in reducing stroke risk in both RCTs (RR = 0.66, 95% CI: 0.50, 0.87 p = 0.004) and cohort studies (RR = 0.67, 95% CI: 0.55, 0.81, p < 0.0001). However, combined administration of metformin with other antihyperglycemic agents had no significant effect on stroke risk reduction in either the RCTs (RR = 0.92, 95% CI: 0.69, 1.22 p = 0.558) or the cohort studies (RR = 0.79, 95% CI: 0.59, 1.06, p = 0.122).

CONCLUSION

Low to moderate level of evidence in RCTs showed that metformin monotherapy could reduce stroke risk in type 2 diabetic patients. However, the preventive effect of metformin in stroke was not observed in patients who received a combination of metformin plus other hypoglycemic agents.

The Lymphatic System In The Brain Clearance Mechanisms - New Therapeutic Perspectives For Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia worldwide. Pathological deposits of neurotoxic proteins within the brain, such as amyloid-ß and hyperphosphorylated tau tangles, are the prominent features in AD. According to recent studies, the newly discovered brain lymphatic system was demonstrated to be crucial in the clearance of metabolic macromolecules from the brain. Meningeal lymphatic vessels located in the dura mater drain the fluid, macromolecules, and immune cells from cerebrospinal fluid (CSF) and transport them, as lymph, to the deep cervical lymph nodes. The lymphatic system provides the perivascular exchange of CSF with interstitial fluid (ISF) and ensures the homeostasis of neuronal interstitial space. In this review, we aim to summarize recent findings on the role of the lymphatic system in AD pathophysiology and discuss possible therapeutic perspectives, targeting the lymphatic clearance mechanisms within the brain.

The mechanisms underlying the actions of Xuefu Zhuyu decoction pretreatment against neurological deficits after ischemic stroke in mice: The mediation of glymphatic function by aquaporin-4 and its anchoring proteins

Ischemic stroke (IS) has been associated with an impairment in glymphatic function. Xuefu Zhuyu Decoction (XFZYD) is widely used in the prevention and treatment of ischemic stroke. We hypothesized that Xuefu Zhuyu decoction pretreatment could attenuate early neurological deficits after ischemic stroke by enhancing the function of the glymphatic system. To prove our hypothesis, we carried out temporary middle cerebral artery occlusion and reperfusion surgery on C57BL/6 mice and then measured neurological score, infarct size and performed hematoxylin-eosin staining to assess stroke outcomes after 24 h of reperfusion. Subsequently, we injected fluorescent tracers in to the cisterna magna and evaluated tracer distribution in coronal brain sections. The polarization of aquaporin-4 (AQP4), colocalization of aquaporin-4, α-dystroglycan, β-dystroglycan and agrin were determined by immunofluorescence. Our research showed that pretreatment with Xuefu Zhuyu decoction significantly alleviated neurological scores, neurological deficits and pathological abnormalities in a mouse model of ischemic stroke. Importantly, Xuefu Zhuyu decoction pretreatment enhanced cerebrospinal fluid influx, protected aquaporin-4 depolarization and promoted the colocalization of aquaporin-4 with its anchoring proteins in the brain. Our findings highlight novel mechanisms underlying the neuroprotective effect of Xuefu Zhuyu decoction pretreatment on ischemic stroke-induced brain damage through the glymphatic system. Xuefu Zhuyu decoction pretreatment may offer a promising approach to slow the onset and progression of ischemic stroke.

Intravenous thrombolysis with 0.65 mg/kg r-tPA may be optimal for Chinese mild-to-moderate stroke

Background

Intravenous recombinant tissue plasminogen activator (r-tPA) with 0.9 mg/kg is the standard treatment for acute ischemic stroke, but it remains unclear whether it is optimal for all patients. We aimed to determine the optimal dose of r-tPA for Chinese stroke based on the data from the INTRECIS study.

Methods

From the INTRECIS cohort, patients receiving intravenous r-tPA within 4.5 h of onset were included. According to r-tPA dose, patients were assigned into seven groups (from 0.60 to 0.90 mg/kg). The primary outcomes were the proportion of excellent functional outcomes and symptomatic intracranial hemorrhage.

Results

Overall, 2,666 patients were included: 156 in 0.60 mg/kg group, 117 in 0.65 mg/kg group, 127 in 0.70 mg/kg group, 188 in 0.75 mg/kg group, 154 in 0.80 mg/kg group, 359 in 0.85 mg/kg group, and 1,565 in 0.90 mg/kg group. After adjustment for baseline characteristics, only 0.65 mg/kg group had significantly higher proportion of excellent functional outcome than 0.90 mg/kg group (79.5 vs. 71.4%, odds ratio = 1.833, 95% CI = 1.006–3.341, adjusted p = 0.048). The subgroup analysis showed no evidence of differences in the odds of having a primary outcome between the two groups by age, admission NIHSS, onset to thrombolysis time, and TOAST classification. There was no significant difference in symptomatic intracranial hemorrhage between groups.

Conclusion

Our study presented the first evidence that intravenous thrombolysis with 0.65 mg/kg r-tPA may be optimal for Chinese mild-to-moderate stroke.

Registration

https://www.clinicaltrials.gov, identifier: NCT 02854592.

Low-dose alteplase for the management of acute ischemic stroke in South Asians: A systematic review on cost, efficacy and safety

INTRODUCTION

South Asia is responsible for more than 40% of the stroke burden and stroke mortality in the developing world. South Asia, which is home to one-fourth of the world's population, is the most densely populated and one of the poorest regions. The majority of patients in this region are unable to afford intravenous thrombolysis (IVT) for acute ischemic stroke (AIS). If low-dose alteplase proves effective and safe in South Asians, it may be a more cost-effective treatment option.

METHODS

The study was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and meta-Analyses) guideline. Researchers searched PubMed, EMBASE, and Google Scholar for English literature from 2005 to 2021. END, ENI, good functional outcome, SICH, and all-cause mortality were used to assess efficacy and safety.

RESULTS

In the low-dose alteplase treated patients, different studies reported 32 to 57% ENI 24 h after IVT, and 7% to 9.7% END. At 3 months follow-up, good functional outcome was achieved by 48%-76.92% of low-dose alteplase treated patients. SICH rates ranged from 0% to 16.6% across studies. Asymptomatic ICH occurred in 5-14% of patients. The mortality rate in all included studies varied from none to 25%.

CONCLUSION

Our systematic review demonstrates that the use of low-dose alteplase for AIS in the South Asians offer comparable efficacy and reduced risk of SICH at a significantly lower cost than standard alteplase dose. Future well-randomized clinical trials are necessary to validate the findings of our study.

Different Doses of Intravenous Tissue-Type Plasminogen Activator for Acute Ischemic Stroke: A Network Meta-Analysis

Background

This study aims to assess the efficacy and safety of different doses of intravenous tissue-type plasminogen activator (tPA) for acute ischemic stroke (AIS) by adopting a network meta-analysis (NMA).

Methods

Studies comparing different doses of tPA in AIS were identified by retrieving electronic databases. NMAs of outcome measures included favorable functional outcome with a modified Rankin scale score (mRS) of 0 or 1 at 3 months after treatment (3M-FF), the functional independence with a mRS of 0, 1, or 2 at 3 months (3M-FI), symptomatic intracranial hemorrhage (sICH) and 3-month all-cause mortality (3M-M). Symptomatic intracranial hemorrhage (sICH) and 3-month all-cause mortality (3M-M) were assessed. Probability-based ranking and surface under cumulative ranking (SUCRA) were performed to identify the best dose of tPA. Inconsistency was evaluated by node-splitting analysis and a loop-specific approach. Publication bias was analyzed by funnel plots.

Results

A total of 14 studies were included in the quantitative synthesis. The NMA results revealed no difference among low (<0.7 mg/kg), moderate (0.8 mg/kg), and standard (0.9 mg/kg) doses of tPA with regard to efficacy and safety. The SUCRAs of 3M-FF and 3M-FI showed that the standard dose ranked first, the moderate dose ranked second, and the low dose ranked third. The SUCRA of sICH showed that the standard dose ranked first (78.1%), the low dose ranked second (61.0%), and the moderate dose ranked third (11.0%). The SUCRAs of 3-month mortality showed that the standard dose ranked first (73.2%), the moderate dose ranked second (40.8%), and the low dose ranked third (36.1%). No significant inconsistency was shown by node-splitting analysis and no publication bias was shown in funnel plots.

Conclusion

Lower dose tPA was comparable to the standard dose with regard to efficacy and safety. Based on the SUCRA results and American Heart Association/American Stroke Association (AHA/ASA) guidelines, the standard dose was still the optimal selection for AIS.

Elaborately Engineering a Self-Indicating Dual-Drug Nanoassembly for Site-Specific Photothermal-Potentiated Thrombus Penetration and Thrombolysis

Thrombotic cardio-cerebrovascular diseases seriously threaten human health. Currently, conventional thrombolytic treatments are challenged by the low utilization, inferior thrombus penetration, and high off-target bleeding risks of most thrombolytic drugs, resulting in unsatisfactory treatment outcomes. Herein, it is proposed that these challenges can be overcome by precisely integrating the conventional thrombolytic strategy with photothermal therapy. After co-assembly engineering optimization, a fibrin-targeting peptide-decorated nanoassembly of DiR (a photothermal probe) and ticagrelor (TGL, an antiplatelet drug) is prepared for thrombus-homing delivery, abbreviated as FT-DT NPs. The elaborately engineered nanoassembly shows multiple advantages, including simple preparation with high drug co-loading capacity, synchronous delivery of two drugs with long systemic circulation, thrombus-targeted accumulation with self-indicating function, as well as photothermal-potentiated thrombus penetration and thrombolysis with high therapeutic efficacy. As expected, FT-DT NPs not only show bright fluorescence signals in the embolized vessels, but also perform photothermal/antiplatelet synergistic thrombolysis in vivo. This study offers a simple and versatile co-delivery nanoplatform for imaging-guided photothermal/antiplatelet dual-modality thrombolysis.

Meta-Analysis of the Effectiveness and Safety of Intravenous Thrombolysis in Patients with Acute Cerebral Infarction

In this paper, a meta-analysis of the effectiveness and safety of intravenous thrombolysis in patients with acute cerebral infarction was carried out, the original literature inclusion criteria and retrieval strategies were developed, and the collection deadline was about new oral anticoagulants and other methods for the antithrombotic intravenous thrombolytic treatment of patients with acute cerebral infarction for the relevant literature on the safety and effectiveness comparison. First, the quality of the literature is evaluated according to whether the included studies are randomized controlled trials, whether there is randomized concealment, whether blinding is used, and whether they are withdrawn or lost to follow-up, and the RevMan 5.2 software is used for meta-analysis. At the same time, grey literature databases such as dissertations were experimentally searched, and all randomized controlled studies (RCT), nonrandomized controlled studies, case-controlled studies, cohort studies, case series reports, etc. of Wingspan in the treatment of intracranial atherosclerotic stenosis were collected. In the prevention of myocardial infarction in patients with acute cerebral infarction, the difference between the two was not statistically significant (RR = 0.82, 95% CI (0.57, 1.17), P = 0.27). Compared with other methods, it can significantly reduce the all-cause mortality of patients with nonvalvular venous thrombolysis, and the difference is statistically significant (RR = 0.90, 95% CI (0.85, 0.96), P = 0.001). Experimental results show that in terms of safety, the new oral anticoagulant is better than other methods in reducing minor bleeding in patients with acute cerebral infarction, and the difference is statistically significant (RR = 0.87, 95% CI (0.76, 0 99), P = 0.03); the effect is better than other methods in reducing the incidence of serious bleeding events, and the difference is statistically significant (RR = 0.79, 95% CI (0.74, 0.85), P < 0.00001).

Thrombus-Targeting Polymeric Nanocarriers and Their Biomedical Applications in Thrombolytic Therapy

Due to the high morbidity and mortality of cardiovascular diseases, there is an urgent need for research on antithrombotic strategies. In view of the short half-life, insufficient drug penetration, poor targeting capabilities, and hemorrhagic side-effects of traditional thrombus treatment methods, the combination of thrombolytic therapy and nanocarriers brought by the development of nanotechnology in recent years may provide effective solutions for these undesirable side-effects caused by insufficient targeting. Polymeric nanocarriers, based on macromolecules and various functional groups, can connect specific targeting molecules together through chemical modification to achieve the protection and targeted delivery of thrombolytic drugs. However, simple chemical molecular modifications may be easily affected by the physiological environment encountered in the circulatory system. Therefore, the modification of nanocarriers with cell membranes can provide camouflage to these platforms and help to extend their circulation time while also imparting them with the biological functions of cell membranes, thus providing them with precise targeting capabilities, among which the most important is the biological modification of platelet membranes. In addition, some nanoparticles with their own therapeutic functions have also been developed, such as polypyrrole, which can exhibit a photothermal effect to induce thrombolysis. Herein, combined with the mechanism of thrombosis and thrombolysis, we outline the recent advances achieved with thrombus-targeting nanocarriers with regard to thrombosis treatment. On this basis, the design considerations, advantages, and challenges of these thrombolytic therapies in clinical transformation are discussed.

Induced pluripotent stem cells can improve thrombolytic effect of low-dose rt-PA after acute carotid thrombosis in rat

Background

Intravenous thrombolysis using recombinant tissue plasminogen activator (rt-PA) is the standard treatment for acute ischemic stroke. Standard-dose rt-PA (0.9 mg/kg) is known to achieve good recanalization but carries a high bleeding risk. Lower dose of rt-PA has less bleeding risk but carries a high re-occlusion rate. We investigate if induced pluripotent stem cells (iPSCs) can improve the thrombolytic effect of low-dose rt-PA (0.45 mg/kg).

Methods

Single irradiation with 6 mW/cm² light-emitting diode (LED) for 4 h at rat common carotid artery was used as thrombosis model according to our previous report. Endothelin-1 (ET-1), intercellular adhesion molecule-1 (ICAM-1), and interleukin 1 beta (IL-1 beta) were used as the inflammatory markers for artery endothelial injury. Angiopoietin-2 (AP-2), brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) were examined in artery wall and iPSCs culture. Animal ultrasound was used to evaluate the stenosis degree of common carotid artery before and at 2 h, 24 h, 4 days and 7 days after LED irradiation.

Results

After LED irradiation alone, there was a persistent occlusion from 2 h to 7 days. Standard-dose rt-PA alone could recanalize the occluded artery from 24 h to 7 days to stenotic degree ≤ 50%. Low-dose rt-PA or 1 × 10⁶ mouse iPSCs alone could not recanalize the occluded arteries from 2 h to 7 days. Combination use of low-dose rt-PA plus 1 × 10⁶ mouse iPSCs caused better recanalization from 24 h to 7 days. ET-1, ICAM-1 and IL-1 beta were strongly expressed after LED irradiation but reduced after iPSCs treatment. AP-2, BDNF and VEGF were rarely induced after LED irradiation but strongly expressed after iPSCs treatment. In vitro study showed iPSCs could express AP-2, BDNF and VEGF.

Conclusion

The adjuvant use of iPSCs may help improving the thrombolytic effect of low-dose rt-PA by suppressing inflammatory factors and inducing angiogenic trophic factors. Stem cells could be a potential regimen in acute thrombolytic therapy to improve recanalization and reduce complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02615-z.

Impact of estimated-weight-base dose of alteplase in acute stroke treatment on clinical outcome

Dosing of recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke treatment is often based on estimated body weight (BW) worldwide in routine clinical practice due to infeasible of accurate BW measurement. The aim of our study is to explore the impact of estimated BW when dosing rt-PA in acute ischemic stroke treatment on clinical outcome. Between January 2013 to May 2018, 126 acute ischemic stroke patients received intravenous rt-PA treatment based on estimated BW dosage were recruited. All patients had actual BW measured in ward after treatment. Based on the dosage of rt-PA given, patients were categorized into three groups, standard dose (0.8-1.0 mg/kg), overdose (>1.0 mg/kg), and underdose (<0.8 mg/kg). Among all 126 patients, 101 (80.2%) patients were treated with standard dose, 12 (9.5%) patients with overdose, and 13 (10.3%) patients with underdose of rt-PA respectively. There was no significant difference between demographic characteristics, pre-morbid risk factors, National Institutes of Health Stroke Scale (NIHSS) score at 24 h, NIHSS score at discharge, modified Rankin scale (mRS) within 0 to 2 in discharge or in 3 months after the event within the three groups. There was also no significant difference in hemorrhagic transformation and symptomatic intracranial hemorrhage (SICH). In conclusion, calculation of the dose of rt-PA based upon the estimated BW to treat acute ischemic stroke patients had no negative impact on the clinical outcome in our study.

Artificial neural network based prediction of postthrombolysis intracerebral hemorrhage and death

Despite the salient benefits of the intravenous tissue plasminogen activator (tPA), symptomatic intracerebral hemorrhage (sICH) remains a frequent complication and constitutes a major concern when treating acute ischemic stroke (AIS). This study explored the use of artificial neural network (ANN)-based models to predict sICH and 3-month mortality for patients with AIS receiving tPA. We developed ANN models based on evaluation of the predictive value of pre-treatment parameters associated with sICH and mortality in a cohort of 331 patients between 2009 and 2018. The ANN models were generated using eight clinical inputs and two outputs. The generalizability of the model was validated using fivefold cross-validation. The performance of each model was assessed according to the accuracy, precision, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). After adequate training, the ANN predictive model AUC for sICH was 0.941, with accuracy, sensitivity, and specificity of 91.0%, 85.7%, and 92.5%, respectively. The predictive model AUC for 3-month mortality was 0.976, with accuracy, sensitivity, and specificity of 95.2%, 94.4%, and 95.5%, respectively. The generated ANN-based models exhibited high predictive performance and reliability for predicting sICH and 3-month mortality after thrombolysis; thus, its clinical application to assist decision-making when administering tPA is envisaged.

Premorbid Use of Statin and Outcome of Acute Ischemic Stroke After Intravenous Thrombolysis: A Meta-Analysis

Background: The association between the premorbid use of statin and the early outcomes of acute ischemic stroke (AIS) after intravenous thrombolysis (IVT) remains uncertain. We performed a meta-analysis of observational studies to evaluate the influence of the premorbid use of statin on functional outcome and symptomatic intracranial hemorrhage (SIH) in AIS after IVT. Methods: Relevant studies were identified by search of PubMed, Embase, and Cochrane's Library databases. Only studies with multivariate analyses were included. A random-effect model, incorporating inter-study heterogeneity, was used to pool the results. Results: Twenty observational studies with 20,752 AIS patients who were treated with IVT were included. The pooled results showed that the premorbid use of statin was not associated with improved 3-month favorable functional outcome [odds ratio (OR): 1.05, 95% confidence interval (CI): 0.87-1.26, p = 0.60, I ² = 52%), 3-month functional independence (OR: 1.13, 95% CI: 0.96-1.33, p = 0.15, I ² = 52%), or 3-month mortality (OR: 1.12, 95% CI: 0.94-1.34, p = 0.20, I ² = 20%). Moreover, the premorbid use of statin was associated with an increased risk of SIH in AIS after IVT (OR: 1.48, 95% CI: 1.12-1.95, p = 0.006, I ² = 60%). Subgroup analyses according to study design, adjustment of baseline low-density lipoprotein cholesterol, and definitions of SIH showed consistent results (p-values for subgroup difference all >0.05). Conclusions: The premorbid use of statin is not associated with improved functional outcomes or mortality but is associated with a higher risk of SIH in AIS patients after IVT.

Emerging nanotherapeutics for antithrombotic treatment

Thrombus causes insufficient blood flow and ischemia damages to brain and heart, leading to life-threatening cardio-cerebrovascular diseases. Development of efficient antithrombotic strategies has long been a high priority, owing to the high morbidity and mortality of thrombotic diseases. With the rapid development of biomedical nanotechnology in diagnosis and treatment of thrombotic disorder, remarkable progresses have been made in antithrombotic nanomedicines in recent years. Herein, we outline the recent advances in this field at the intersection of thrombus theranostics and biomedical nanotechnology. First, thrombus diagnosis techniques based on biomedical nanotechnology are presented. Then, emerging antithrombotic nanotherapeutics are overviewed, including thrombus-targeting strategies, thrombus stimuli-responsive nanosystems and phase transition-driven nanotherapeutics. Furthermore, multifunctional nanosystems for combination theranostics of thrombotic diseases are discussed. Finally, the design considerations, advantages and challenges of these biomedical nanotechnology-driven therapeutics in clinical translation are highlighted.

Similar thrombolysis outcomes in acute stroke patients with and without atrial fibrillation if pre-stroke CHA2DS2-VASc score is low: A retrospective study

The prognosis of acute ischemic stroke patients treated with intravenous (IV) recombinant tissue plasminogen activator (rtPA) is poorer in patients with atrial fibrillation (AF) than patients without AF, which might be related to the greater stroke severity in AF patients. Higher pre-stroke CHA2DS2-VASc scores are associated with greater stroke severity and poorer outcomes. AF Patients tend to have higher CHA2DS2-VASc scores than the non-AF patients. We thus hypothesized that pre-stroke CHA2DS2-VASc scores can be used to improve outcome stratification of IV thrombolysis therapy in acute stroke patients with and without AF. We retrospectively enrolled ischemic stroke patients who received IV-rtPA and categorized them into 2 groups: low-risk (CHA2DS2-VASc scores ≤ 2) and high-risk (CHA2DS2-VASc scores ≥ 3) groups. We compared the outcomes between AF and non-AF patients and the interactive effects of the levels of CHA2DS2-VASc scores on this outcome difference. In the low-risk group, there was no difference in outcomes between the AF and non-AF patients. In the high-risk group, the AF patients had worse outcomes at 3 and 6 months. Our results suggest that pre-stroke CHA2DS2-VASc scores are a useful outcome predictor of IV thrombolytic therapy in acute stroke patients with AF.

Safety and Efficacy of Intravenous Thrombolytic Therapy in Patients With Acute Posterior Circulation Stroke: A Single-Center Study

BACKGROUND AND PURPOSE

The safety and efficacy of intravenous thrombolytic therapy (IVT) for posterior circulation stroke (PCS) in the real world are rarely studied. This study was designed to evaluate the prestroke and baseline characteristics, stroke sub-types, complications, and outcomes of PCS patients and compare them with anterior circulation stroke (ACS) after intravenous thrombolysis.

METHODS

Data of consecutive patients with PCS and ACS treated with alteplase in a standard dose of 0.9 mg/kg in our stroke center were collected and analyzed retrospectively. Presenting characteristics, hemorrhage transformation, mortality, and favorable outcomes (modified Rankin scale 0 or 1) at 90 days were compared between PCS and ACS patients.

RESULTS

A total of 462 patients were included in this study, including 350 (75.8%) in ACS group and 112 (24.2%) in PCS group. A history of coronary artery disease was significantly more common in ACS patients than that in PCS patients (15.1% versus 6.3%, P = .015). There was no significant difference in fast glucose and baseline NIHSS scores between PCS and ACS groups. In PCS group, 7 patients (6.3%) had hemorrhage transformation after IVT and 5 patients (4.5%) were symptomatic versus 32 (9.1%) and 22 (6.3%) in ACS group (P > .05). 75.5% PCS patients versus 72.2% ACS patients had excellent recovery outcomes (mRS 0-1) at 90 days (P = .507). For PCS patients, logistic regression analysis after adjusting the covariates identified age (P = .047, OR .920, 95% CI = .847-.999) and atrial fibrillation (P = .007, OR 12.149, 95% CI = 1.966-75.093) as independent significant predictors of hemorrhage transformation. In addition, atrial fibrillation was also an independent predictor of symptomatic intracranial hemorrhage (P = .008, OR 21.176, 95% CI = 2.228-201.273). Multivariate logistic analysis identified hemorrhage transformation (P = .012; OR .131, 95% CI = .027-.644) and onset to drug time (P = .026, OR 1.006, 95% CI = 1.001-1.011) as independent predictors of functional independence (mRS 0-2). Symptomatic intracranial hemorrhage (P = .007, OR 15.094, 95% CI = 2.097-108.661) and baseline NIHSS score (P = .050; OR 1.070, 95% CI = 1.000-1.145) were independent predictors of mortality.

CONCLUSION

Our results suggest that IVT in PCS patients is safe and effective as that in ACS patients. In PCS patients, long onset to needle time and hemorrhage transformation were identified as independent predictors of unfavorable outcomes.

Thrombolysis Following Heparin Reversal With Protamine Sulfate in Acute Ischemic Stroke: Case Series and Literature Review

INTRODUCTION

Administering intravenous IV tissue plasminogen activator (tPA) is the recommended standard of care in acute ischemic stroke (AIS), although it is not recommended to administer intravenous thrombolysis with tPA following heparin reversal with protamine sulfate in patients with AIS.

METHODS

We describe a case series of three patients and the most comprehensive literature review published to date in this specific subset of AIS patients undergoing thrombolysis following heparin reversal with protamine sulfate. The literature review was based on a scoping review methodology performed on four databases; PubMed, CINAHL, Web of Science, and Cochrane Library. All sources were searched from the inauguration of the database until February 2019. A total of six articles involving eight patients were identified.

RESULTS

The primary safety outcome of no symptomatic intracranial hemorrhage (sICH) was met in all eleven patients, although only seven cases had a good functional outcome at 3 months.

CONCLUSIONS

In appropriately selected AIS patients, coagulopathy correction appears to be safe from an sICH standpoint and may be beneficial. However, given the potential for bias with observational databases, case reports and case series, extreme caution is warranted in applying these results to routine clinical practice.

Current Drug Treatment of Acute Ischemic Stroke: Challenges and Opportunities

Patient-level health outcomes for acute ischemic stroke have significantly improved in the last decade primarily because of superior overall case management, availability of tailored drug interventions, and advances in endovascular procedures. Nevertheless, disease registries show a "quality gap" across social determinants of health and between in-hospital and community-onset strokes. Several factors, including financing and infrastructure constraints, limited expertise, and clinical uncertainty, still prevent adherence to evidence-based clinical guidelines and optimal care pathways. This paper critically appraises existing evidence on the use of drug therapies in acute ischemic stroke, in an attempt to resolve physician-related subjective barriers for effective acute management of the disease. We conclude that intravenous administration of rt-PA (recombinant tissue-type plasminogen activator, alteplase) is an essential component of acute-phase pharmacologic treatment and a driver for the improvement of overall ischemic stroke health outcomes. The safety profile of alteplase and similar treatments are well within the patient benefit zone of eligible patients when compared to non-treatment alternatives. Monomodal neuroprotective drugs with single or pleiotropic mechanisms of action have failed to support long-term sustainable results. Drugs with complex mechanisms of action that promote neurorecovery, such as cerebrolysin, are valid options for adjunctive treatment of acute ischemic stroke. Recent years have shown clear improvements in the methodology and design of clinical trials, with an increase in overall internal and external validity. A better understanding of study limitations has not hindered, but enhanced their potential to contribute, together with sometimes superior data sources, to health decision making.

Deficiency of tPA Exacerbates White Matter Damage, Neuroinflammation, Glymphatic Dysfunction and Cognitive Dysfunction in Aging Mice

Tissue plasminogen activator (tPA) is a serine protease primarily involved in mediating thrombus breakdown and regulating catabolism of amyloid-beta (Aβ). The aim of this study is to investigate age-dependent decline of endogenous tPA and the effects of tPA decline on glymphatic function and cognitive outcome in mice. Male, young (3m), adult (6m) and middle-aged (12m) C57/BL6 (wild type) and tPA knockout (tPA^-/-) mice were subject to a battery of cognitive tests and white matter (WM) integrity, neuroinflammation, and glymphatic function were evaluated. Adult WT mice exhibit significantly decreased brain tPA level compared to young WT mice and middle-aged WT mice have significantly lower brain tPA levels than young and adult WT mice. Middle-aged WT mice exhibit significant neuroinflammation, reduced WM integrity and increased thrombin deposition compared to young and adult mice, and increased blood brain barrier (BBB) permeability and reduced cognitive ability compared to young WT mice. In comparison to adult WT mice, adult tPA^-/- mice exhibit significant BBB leakage, decreased dendritic spine density, increased thrombin deposition, neuroinflammation, and impaired functioning of the glymphatic system. Compared to age-matched WT mice, adult and middle-aged tPA^-/- mice exhibit significantly increased D-Dimer expression and decreased perivascular Aquaporin-4 expression. Compared to age-matched WT mice, young, adult and middle-aged tPA^-/- mice exhibit significant cognitive impairment, axonal damage, and increased deposition of amyloid precursor protein (APP), Aβ, and fibrin. Endogenous tPA may play an important role in contributing to aging induced cognitive decline, axonal/WM damage, BBB disruption and glymphatic dysfunction in the brain.