Usefulness of ADAMTS13 to predict response to recanalization therapies in acute ischemic stroke

Velvet antler polypeptide (VAP) protects against cerebral ischemic injury through NF-κB signaling pathway in vitro

OBJECTIVE

Velvet antler polypeptide (VAP) has been shown to play important roles in the immune and nervous systems. The purpose of this study was to investigate the protective effects of VAP on cerebral ischemic injury with the involvement of NF-κB signaling pathway in vitro.

MATERIALS AND METHODS

PC-12 cells stimulated by oxygen-glucose deprivation/reperfusion (OGD/R) was used to mimic cerebral ischemic injury in vitro. The levels of ROS, SOD, and intracellular concentrations of Ca2+ were measured by the relevant kits. Meanwhile, the expressions of inflammatory cytokines (IL-6, IL-1β, and TNF-α) were determined by ELISA kit assay. In addition, MTT, EdU, and flow cytometry assays were used to measure the cell proliferation and apoptosis. Besides which, the related proteins of NF-κB signaling pathway were measured by western blotting assay.

RESULTS

VAP alleviated cerebral ischemic injury by reducing OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells in a time dependent manner. Mechanistically, VAP inhibited the levels of p-p65 and p-IkB-α in a time dependent manner, which was induced by OGD/R operation. Moreover, NF-κB agonist diprovocim overturned the suppression effects of VAP on OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells.

CONCLUSIONS

The results demonstrate that VAP may alleviate cerebral ischemic injury by suppressing the activation of NF-κB signaling pathway.

Acute Ischemic Stroke in the Clinic and the Laboratory: Targets for Translational Research

Ischemic stroke research has enabled significant advancements in diagnosis, treatment, and management of this debilitating disease, yet challenges remain standing in the way of better patient prognoses. In this narrative review, a fictional case illustrates challenges and uncertainties that medical professionals still face - penumbra identification, lack of neuroprotective agents, side-effects of tissue plasminogen activator, dearth of molecular biomarkers, incomplete microvascular reperfusion or no-reflow, post-recanalization hyperperfusion, blood pressure management and procedural anesthetic effects. The current state of the field is broadly reviewed per topic, with the aim to introduce a broad audience (scientist and clinician alike) to recent successes in translational stroke research and pending scientific queries that are tractable for preclinical assessment. Opportunities for co-operation between clinical and experimental stroke experts are highlighted to increase the size and frequency of strides the field makes to improve our understanding of this disease and ways of treating it.

Predictive effect of net water uptake on futile recanalisation in patients with acute large-vessel occlusion stroke

AIM

To determine whether net water uptake (NWU) based on automated software evaluation could predict futile recanalisation in patients with acute anterior circulation large-vessel occlusion (LVO).

MATERIALS AND METHODS

Patients with acute anterior circulation LVO undergoing mechanical thrombectomy in Jinling Hospital were evaluated retrospectively. NWU and other baseline data were evaluated by performing univariate and multivariate analyses. The primary endpoint was 90-day modified Rankin scale score ≥3. A nomogram to predict poor clinical outcomes was developed based on multivariate logistic regression analysis.

RESULTS

Overall, 135 patients who underwent thrombectomy with a TICI grade ≥2b were enrolled. In multivariate logistic regression analysis, the following factors were identified as independent predictors of futile recanalisation: age (odds ratio [OR]: 1.055, 95 % confidence interval [CI]: 1.004-1.110, p=0.035), female (OR: 0.289, 95 % CI: 0.098-0.850, p=0.024), hypertension (OR: 3.182, 95 % CI: 1.160-8.728, p=0.025), high blood glucose level (OR: 1.36, 95 % CI: 1.087-1.701, p=0.007), admission National Institutes of Health Stroke Scale score (OR: 1.082, 95 % CI: 1.003-1.168, p=0.043), and NWU (OR: 1.312, 95 % CI: 1.038-1.659, p=0.023).

CONCLUSIONS

NWU based on Alberta Stroke Program Early Computed Tomography (CT) Score (ASPECTS) could be used to predict the occurrence of futile recanalisation in patients with acute anterior circulation LVO ischaemic stroke.

ADAMTS-13 activity in stroke of known and unknown cause: Relation to vascular risk factor burden

Background

The identification of the underlying mechanism in ischemic stroke has important implications for secondary prevention. A disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS-13) has antithrombotic properties and was repeatedly implicated in the pathophysiology of stroke. In this study, we, therefore, aimed to investigate whether ADAMTS-13 is associated with stroke etiology and the burden of vascular risk factors.

Methods

We determined ADAMTS-13 activity in two prospectively recruited stroke cohorts in the long-term course after the event. Cohort 1 (n = 88) consisted of patients who suffered a stroke due to embolic stroke of undetermined source (ESUS), cardioembolic stroke due to atrial fibrillation (AF), large-artery atherosclerosis, or small vessel disease. In cohort 2, patients with cryptogenic stroke and patent foramen ovale (PFO) scheduled for PFO closure (n = 38) were enrolled. As measures of vascular risk factor burden, the CHA₂DS₂VASC score, the Essen Stroke Risk Score (ESRS), and the Risk of Paradoxical Embolism (RoPE) score were calculated, as appropriate.

Results

ADAMTS-13 activity was lower in patients with AF-related stroke compared to patients with ESUS (p = 0.0227), which was, however, due to confounding by vascular risk factors. ADAMTS-13 activity inversely correlated with the ESRS (r = -0.452, p < 0.001) and CHA₂DS₂VASC (r = -0.375, p < 0.001) in cohort 1. In accordance with these findings, we found a positive correlation between ADAMTS-13 activity and the RoPE score in cohort 2 (r = 0.413, p = 0.010).

Conclusion

ADAMTS-13 activity is inversely correlated with the number of vascular risk factors across different stroke etiologies. Further study is warranted to establish ADAMTS-13 as a mediator of cerebrovascular risk.

Association of Blood Biomarkers of Inflammation With Penumbra Consumption After Mechanical Thrombectomy in Patients With Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

The objective of this study was to assess the relationship between blood biomarkers of inflammation and lesion growth within the penumbra in acute ischemic stroke (AIS) patients treated with mechanical thrombectomy (MT).

METHODS

The HIBISCUS-STROKE cohort enrolled patients admitted in the Lyon Stroke Center for an anterior circulation AIS treated with MT after brain MRI assessment. Lesion growth within the penumbra was assessed on day 6 MRI using a voxel-based nonlinear coregistration method and dichotomized into low and high according to the median value. C-reactive protein, interleukin (IL)-6, IL-8, IL-10, monocyte chemoattractant protein-1, soluble tumor necrosis factor receptor I, soluble form suppression of tumorigenicity 2 (sST2), soluble P-selectin, vascular cellular adhesion molecule-1, and matrix metalloproteinase-9 were measured in sera at 4 time points within the first 48 hours. Reperfusion was considered as successful if Thrombolysis in Cerebral Infarction score was 2b/2c/3. A multiple logistic regression model was performed to detect any association between area under the curve (AUC) of these biomarkers within the first 48 hours and a high lesion growth within the penumbra.

RESULTS

Ninety patients were included. The median lesion growth within the penumbra was 2.3 (0.7-6.2) mL. On multivariable analysis, a high sST2 AUC (OR 3.77, 95% CI 1.36-10.46), a high baseline DWI volume (OR 3.65, 95% CI 1.32-10.12), and a lack of successful reperfusion (OR 0.19, 95% CI 0.04-0.92) were associated with a high lesion growth within the penumbra. When restricting analyses to patients with successful reperfusion (n = 76), a high sST2 AUC (OR 5.03, 95% CI 1.64-15.40), a high baseline DWI volume (OR 3.74, 95% CI 1.22-11.53), and a high penumbra volume (OR 3.25, 95% CI 1.10-9.57) remained associated with a high lesion growth within the penumbra.

DISCUSSION

High sST2 levels within the first 48 hours are associated with a high lesion growth within the penumbra.

The utility of therapeutic hypothermia on cerebral autoregulation

Cerebral autoregulation (CA) dysfunction is a strong predictor of clinical outcome in patients with acute brain injury (ABI). CA dysfunction is a potential pathologic defect that may lead to secondary injury and worse functional outcomes. Early therapeutic hypothermia (TH) in patients with ABI is controversial. Many factors, including patient selection, timing, treatment depth, duration, and rewarming strategy, impact its clinical efficacy. Therefore, optimizing the benefit of TH is an important issue. This paper reviews the state of current research on the impact of TH on CA function, which may provide the basis and direction for CA-oriented target temperature management.

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.

Immediate outcome prognostic value of plasma factors in patients with acute ischemic stroke after intravenous thrombolytic treatment

In the present study, we explored multiple plasma factors to predict the outcomes of patients with AIS after IVT. Fifty AIS patients who received IVT with alteplase were recruited and divided into two groups according to their NIHSS scores. Serum from all subjects was collected to quantitatively analyze the levels of different plasma factors, IL-6, MMP-9, ADAMTS13, TNC, GSN and TRX, using Luminex assays or ELISA measurements. Compared with the levels assessed at the onset of AIS, the levels of MMP-9 (P < 0.001), ADAMTS13 (P < 0.001), and TRX (P < 0.001) significantly decreased after IVT. The level of IL-6 was significantly increased in the NIHSS > 5 group at admission (P < 0.001) compared to the NIHSS ≤ 5 group. AIS patients with a poor prognosis had lower levels of ADAMTS13 at 72 h post-IVT compared with patients with a good prognosis (P = 0.021). IL-6 also was notably higher in the poor outcome group (P = 0.012). After adjusting for confounders, ADAMTS13 at 72 h post-IVT was an independent protective factor for prognosis in AIS patients with an adjusted OR of 0.07 (P = 0.049), whereas IL-6 was an independent predictor of risk for AIS patients with an adjusted OR of 1.152 (P = 0.028). IVT decreased MMP-9, ADAMTS13, and TRX levels in the plasma of AIS patients. Patients with a NIHSS score of less than 5 exhibited lower IL-6 levels, indicating that increased levels of IL-6 correlated with AIS severity after IVT. Therefore, IL-6 and ADAMTS13 might be useful plasma markers to predict the prognosis in AIS patients at 90-days after IVT.

Association between blood pressure variability and clinical outcomes after successful recanalization in patients with large vessel occlusion stroke after mechanical thrombectomy

Objective

Nearly half of patients who undergo mechanical thrombectomy (MT) do not experience a favorable outcome. The association between blood pressure fluctuation and clinical outcomes after successful MT is controversial. We evaluated the influence of blood pressure variability (BPV) on the clinical outcomes of stroke patients with large vessel occlusion (LVO) who underwent successful recanalization after MT.

Methods

Patients with anterior circulation LVO stroke who underwent successful emergency MT (modified Thrombolysis in Cerebral Infarction, mTICI ≥ 2b) at the Shanghai Tenth People's Hospital of Tongji University from 2017 to 2021 were enrolled. Multivariate logistic models were used to investigate the association between BPV (mean arterial pressure [MAP] assessed using the standard deviation [SD]) and clinical outcomes. The primary outcome was 90-day modified Rankin Scale scores (mRS), and the secondary outcomes were 30-day mortality and symptomatic intracranial hemorrhage (sICH).

Results

A total of 458 patients (56.8% men), with a mean age of 72 ± 1 years, were enrolled. Among them, 207 (45.2%) patients had unfavorable functional outcomes (mRS score 3–6) at 90 days, 61 (13.3%) patients died within 30 days, and 20 (4.4%) patients had sICH. In a fully adjusted model, BPV was associated with a higher risk of a 90-day mRS score of 3–6 (P = 0.04), 30-day mortality (P < 0.01), and sICH (P < 0.01). A significant interaction between MAP SD and rescue futile recanalization treatment was observed (P < 0.01).

Conclusions

Among patients with LVO stroke who underwent successful recanalization, higher BPV was associated with worse functional outcomes, especially in those who underwent rescue treatment.

Composition and Organization of Acute Ischemic Stroke Thrombus: A Wealth of Information for Future Thrombolytic Strategies

During the last decade, significant progress has been made in understanding thrombus composition and organization in the setting of acute ischemic stroke (AIS). In particular, thrombus organization is now described as highly heterogeneous but with 2 preserved characteristics: the presence of (1) two distinct main types of areas in the core—red blood cell (RBC)-rich and platelet-rich areas in variable proportions in each thrombus—and (2) an external shell surrounding the core composed exclusively of platelet-rich areas. In contrast to RBC-rich areas, platelet-rich areas are highly complex and are mainly responsible for the thrombolysis resistance of these thrombi for the following reasons: the presence of platelet-derived fibrinolysis inhibitors in large amounts, modifications of the fibrin network structure resistant to the tissue plasminogen activator (tPA)-induced fibrinolysis, and the presence of non-fibrin extracellular components, such as von Willebrand factor (vWF) multimers and neutrophil extracellular traps. From these studies, new therapeutic avenues are in development to increase the fibrinolytic efficacy of intravenous (IV) tPA-based therapy or to target non-fibrin thrombus components, such as platelet aggregates, vWF multimers, or the extracellular DNA network.

Plasma Lipid Mediators Associate With Clinical Outcome After Successful Endovascular Thrombectomy in Patients With Acute Ischemic Stroke

Background

Neuroinflammatory response contributes to early neurological deterioration (END) and unfavorable long-term functional outcome in patients with acute ischemic stroke (AIS) who recanalized successfully by endovascular thrombectomy (EVT), but there are no reliable biomarkers for their accurate prediction. Here, we sought to determine the temporal plasma profiles of the bioactive lipid mediators lipoxin A4 (LXA4), resolvin D1 (RvD1), and leukotriene B4 (LTB4) for their associations with clinical outcome.

Methods

We quantified levels of LXA4, RvD1, and LTB4 in blood samples retrospectively and longitudinally collected from consecutive AIS patients who underwent complete angiographic recanalization by EVT at admission (pre-EVT) and 24 hrs post-EVT. The primary outcome was unfavorable long-term functional outcome, defined as a 90-day modified Rankin Scale score of 3-6. Secondary outcome was END, defined as an increase in National Institutes of Health Stroke Scale (NIHSS) score ≥4 points at 24 hrs post-EVT.

Results

Eighty-one consecutive AIS patients and 20 healthy subjects were recruited for this study. Plasma levels of LXA4, RvD1, and LTB4 were significantly increased in post-EVT samples from AIS patients, as compared to those of healthy controls. END occurred in 17 (20.99%) patients, and 38 (46.91%) had unfavorable 90-day functional outcome. Multiple logistic regression analyses demonstrated that post-EVT levels of LXA4 (adjusted odd ratio [OR] 0.992, 95% confidence interval [CI] 0.987-0.998), ΔLXA4 (adjusted OR 0.995, 95% CI 0.991-0.999), LTB4 (adjusted OR 1.003, 95% CI 1.001-1.005), ΔLTB4 (adjusted OR 1.004, 95% CI 1.002-1.006), and post-EVT LXA4/LTB4 (adjusted OR 0.023, 95% CI 0.001-0.433) and RvD1/LTB4 (adjusted OR 0.196, 95% CI 0.057-0.682) ratios independently predicted END, and post-EVT LXA4 levels (adjusted OR 0.995, 95% CI 0.992-0.999), ΔLXA4 levels (adjusted OR 0.996, 95% CI 0.993-0.999), and post-EVT LXA4/LTB4 ratio (adjusted OR 0.285, 95% CI 0.096-0.845) independently predicted unfavorable 90-day functional outcome. These were validated using receiver operating characteristic curve analyses.

Conclusions

Plasma lipid mediators measured 24 hrs post-EVT were independent predictors for early and long-term outcomes. Further studies are needed to determine their causal-effect relationship, and whether the imbalance between anti-inflammatory/pro-resolving and pro-inflammatory lipid mediators could be a potential adjunct therapeutic target.

Review of studies on dynamic cerebral autoregulation in the acute phase of stroke and the relationship with clinical outcome

Acute stroke is associated with high morbidity and mortality. In the last decades, new therapies have been investigated with the aim of improving clinical outcomes in the acute phase post stroke onset. However, despite such advances, a large number of patients do not demonstrate improvement, furthermore, some unfortunately deteriorate. Thus, there is a need for additional treatments targeted to the individual patient. A potential therapeutic target is interventions to optimize cerebral perfusion guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). This narrative led to the development of the INFOMATAS (Identifying New targets FOr Management And Therapy in Acute Stroke) project, designed to foster interventions directed towards understanding and improving hemodynamic aspects of the cerebral circulation in acute cerebrovascular disease states. This comprehensive review aims to summarize relevant studies on assessing dCA in patients suffering acute ischemic stroke, intracerebral haemorrhage, and subarachnoid haemorrhage. The review will provide to the reader the most consistent findings, the inconsistent findings which still need to be explored further and discuss the main limitations of these studies. This will allow for the creation of a research agenda for the use of bedside dCA information for prognostication and targeted perfusion interventions.

ADAM and ADAMTS disintegrin and metalloproteinases as major factors and molecular targets in vascular malfunction and disease

A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are two closely related families of proteolytic enzymes. ADAMs are largely membrane-bound enzymes that act as molecular scissors or sheddases of membrane-bound proteins, growth factors, cytokines, receptors and ligands, whereas ADAMTS are mainly secreted enzymes. ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and transmembrane domain. Similarly, ADAMTS family members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but instead of a transmembrane domain they have thrombospondin motifs. Most ADAMs and ADAMTS are activated by pro-protein convertases, and can be regulated by G-protein coupled receptor agonists, Ca²⁺ ionophores and protein kinase C. Activated ADAMs and ADAMTS participate in numerous vascular processes including angiogenesis, vascular smooth muscle cell proliferation and migration, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs and ADAMTS also play a role in vascular malfunction and cardiovascular diseases such as hypertension, atherosclerosis, coronary artery disease, myocardial infarction, heart failure, peripheral artery disease, and vascular aneurysm. Decreased ADAMTS13 is involved in thrombotic thrombocytopenic purpura and microangiopathies. The activity of ADAMs and ADAMTS can be regulated by endogenous tissue inhibitors of metalloproteinases and other synthetic small molecule inhibitors. ADAMs and ADAMTS can be used as diagnostic biomarkers and molecular targets in cardiovascular disease, and modulators of ADAMs and ADAMTS activity may provide potential new approaches for the management of cardiovascular disorders.

Predictors of futile recanalization after endovascular treatment in acute ischemic stroke: a meta-analysis

BACKGROUND

Despite successful recanalization after endovascular treatment, many patients with acute ischemic stroke due to large vessel occlusion still show functional dependence, namely futile recanalization.

METHODS

PubMed and Embase were searched up to April 30, 2021. Studies that reported risk factors for futile recanalization following endovascular treatment of acute ischemic stroke were included. The mean difference (MD) or odds ratio (OR) and 95% confidence interval (95% CI) of each study were pooled for a meta-analysis.

RESULTS

Twelve studies enrolling 2138 patients were included. The pooled analysis showed that age (MD 5.81, 95% CI 4.16 to 7.46), female sex (OR 1.40, 95% CI 1.16 to 1.68), National Institutes of Health Stroke Scale (NIHSS) score (MD 4.22, 95% CI 3.38 to 5.07), Alberta Stroke Program Early CT Score (ASPECTS) (MD -0.71, 95% CI -1.23 to -0.19), hypertension (OR 1.73, 95% CI 1.43 to 2.09), diabetes (OR 1.78, 95% CI 1.41 to 2.24), atrial fibrillation (OR 1.24, 95% CI 1.01 to 1.51), admission systolic blood pressure (MD 4.98, 95% CI 1.87 to 8.09), serum glucose (MD 0.59, 95% CI 0.37 to 0.81), internal carotid artery occlusion (OR 1.85, 95% CI 1.17 to 2.95), pre-treatment intravenous thrombolysis (OR 0.67, 95% CI 0.55 to 0.83), onset-to-puncture time (MD 16.92, 95% CI 6.52 to 27.31), puncture-to-recanalization time (MD 12.37, 95% CI 7.96 to 16.79), and post-treatment symptomatic intracerebral hemorrhage (OR 6.09, 95% CI 3.18 to 11.68) were significantly associated with futile recanalization.

CONCLUSION

This study identified female sex, comorbidities, admission systolic blood pressure, serum glucose, occlusion site, non-bridging therapy, and post-procedural complication as predictors of futile recanalization, and also confirmed previously reported factors. Further large-scale prospective studies are needed.

Circulating Cytokines and Growth Factors in Acute Cerebral Large Vessel Occlusion-Association with Success of Endovascular Treatment

Mechanical thrombectomy (MT) is a highly efficient treatment in patients with acute ischemic stroke due to large vessel occlusion (LVO). However, in a relevant proportion of LVO, no sufficient recanalization can be achieved. The composition of cerebral thrombi is highly heterogeneous and may constitute a relevant factor for insufficient reperfusion. We hypothesized that circulating cytokines and growth factors involved in thromboinflammation and platelet activation may be associated with reperfusion status and thrombus composition in patients undergoing MT. An according biomarker panel was measured in plasma specimens taken prior to MT and at a 7-day follow-up. The reperfusion status was categorized into sufficient or insufficient. The composition of retrieved thrombi was histologically analyzed. Differences of baseline biomarker concentrations between insufficient and sufficient reperfusions were highest for interferon (IFN)-γ, epidermal growth factor, platelet-derived growth factor (PDGF)-AB/BB, and IFN-γ-induced protein 10 (IP-10/CXCL10). After applying correction for multiple comparisons and logistic regression analysis adjusting for stroke etiology, intravenous thrombolysis, and vascular risk factors, PDGF-AB/BB was identified as an independent predictor of reperfusion status (odds ratio: 0.403; 95% confidence interval: 0.199-0.819). Histological analysis revealed that the majority of thrombi had a mixed composition. In conclusion, this study provides the first evidence that cytokines and growth factors are potential effectors in patients undergoing MT for the treatment of acute ischemic stroke.

Cerebral Autoregulation in Ischemic Stroke: From Pathophysiology to Clinical Concepts

Ischemic stroke (IS) is one of the most impacting diseases in the world. In the last decades, new therapies have been introduced to improve outcomes after IS, most of them aiming for recanalization of the occluded vessel. However, despite this advance, there are still a large number of patients that remain disabled. One interesting possible therapeutic approach would be interventions guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). Supportive hemodynamic therapies aiming to optimize perfusion in the ischemic area could protect the brain and may even extend the therapeutic window for reperfusion therapies. However, the knowledge of how to implement these therapies in the complex pathophysiology of brain ischemia is challenging and still not fully understood. This comprehensive review will focus on the state of the art in this promising area with emphasis on the following aspects: (1) pathophysiology of CA in the ischemic process; (2) methodology used to evaluate CA in IS; (3) CA studies in IS patients; (4) potential non-reperfusion therapies for IS patients based on the CA concept; and (5) the impact of common IS-associated comorbidities and phenotype on CA status. The review also points to the gaps existing in the current research to be further explored in future trials.

Association of Interleukin-6 Levels and Futile Reperfusion After Mechanical Thrombectomy

OBJECTIVE

To assess whether interleukin-6 (IL-6) level is a marker of futile reperfusion in patients with acute ischemic stroke (AIS) with large vessel occlusion treated with mechanical thrombectomy (MT).

METHODS

The Cohort of Patients to Identify Biological and Imaging Markers of Cardiovascular Outcomes in Stroke (HIBISCUS-STROKE) includes patients with AIS treated with MT after MRI. We performed a sequential assessment of IL-6 (admission, 6 hours, 24 hours, 48 hours and 3 months from admission). Among patients with successful reperfusion (Thrombolysis in Cerebral Infarction scale 2b/3), reperfusion was considered effective if 3-month modified Rankin Scale (mRS) score was 0 to 2 and futile if 3-month mRS score was 3 to 6. Our model was adjusted for the main confounding variables.

RESULTS

One hundred sixty-four patients represent the study population. One hundred thirty-three patients had successful reperfusion (81.1%), while in 46 (34.6%), reperfusion was classified as futile. In single-variable analyses, high IL-6 levels at 6, 24, and 48 hours in combination with a higher age, a prestroke mRS score >2, a history of hypertension or diabetes, lack of current smoking, a higher baseline NIH Stroke Scale score, the absence of associated intravenous thrombolysis, an intracranial internal carotid artery or a tandem occlusion, and an increased infarct growth were associated with futile reperfusion. After multivariable analyses, a high IL-6 level at 24 hours (odds ratio 6.15, 95% confidence interval 1.71-22.10) remained associated with futile reperfusion.

CONCLUSIONS

IL-6 is a marker of futile reperfusion in the setting of MT.

Plasmin Generation Potential and Recanalization in Acute Ischaemic Stroke; an Observational Cohort Study of Stroke Biobank Samples

Rationale: More than half of patients who receive thrombolysis for acute ischaemic stroke fail to recanalize. Elucidating biological factors which predict recanalization could identify therapeutic targets for increasing thrombolysis success.

Hypothesis: We hypothesize that individual patient plasmin potential, as measured by in vitro response to recombinant tissue-type plasminogen activator (rt-PA), is a biomarker of rt-PA response, and that patients with greater plasmin response are more likely to recanalize early.

Methods: This study will use historical samples from the Barcelona Stroke Thrombolysis Biobank, comprised of 350 pre-thrombolysis plasma samples from ischaemic stroke patients who received serial transcranial-Doppler (TCD) measurements before and after thrombolysis. The plasmin potential of each patient will be measured using the level of plasmin-antiplasmin complex (PAP) generated after in-vitro addition of rt-PA. Levels of antiplasmin, plasminogen, t-PA activity, and PAI-1 activity will also be determined. Association between plasmin potential variables and time to recanalization [assessed on serial TCD using the thrombolysis in brain ischemia (TIBI) score] will be assessed using Cox proportional hazards models, adjusted for potential confounders.

Outcomes: The primary outcome will be time to recanalization detected by TCD (defined as TIBI ≥4). Secondary outcomes will be recanalization within 6-h and recanalization and/or haemorrhagic transformation at 24-h. This analysis will utilize an expanded cohort including ~120 patients from the Targeting Optimal Thrombolysis Outcomes (TOTO) study.

Discussion: If association between proteolytic response to rt-PA and recanalization is confirmed, future clinical treatment may customize thrombolytic therapy to maximize outcomes and minimize adverse effects for individual patients.

Biomarkers of Unfavorable Outcome in Acute Ischemic Stroke Patients with Successful Recanalization by Endovascular Thrombectomy

<b><i>Background:</i></b> We aimed to identify plasma markers of unfavorable outcomes for patients with acute ischemic stroke (AIS) after recanalization by endovascular thrombectomy (EVT). <b><i>Methods:</i></b> From November 2017 to May 2019, we prospectively collected 61 AIS patients due to anterior large vessel occlusion who achieved recanalization by EVT. Plasma samples were obtained between 18 and 24 h after recanalization. Unfavorable outcomes included futile recanalization at 90 days and overall early complications within 7 days after EVT. <b><i>Results:</i></b> After adjustment for age and initial National Institute of Health Stroke Scale (NIHSS), matrix metalloproteinase-9 (MMP-9), tenascin-C, thioredoxin, ADAMTS13, and gelsolin were independently associated with both futile recanalization and overall early complications significantly (all <i>p</i> &#x3c; 0.05), while C-reactive protein (CRP) was independently associated with overall early complications (<i>p</i> = 0.031) but at the limit of significance for futile recanalization (<i>p</i> = 0.051). The baseline clinical model (BCM) (including age and initial NIHSS) demonstrated discriminating ability to indicate futile recanalization (area under the curve [AUC] 0.807, 95% confidence interval [CI] 0.693–0.921) and overall early complications (AUC 0.749, 95% CI 0.611–0.887). BCM+MMP-9+thioredoxin enhanced discrimination (AUC 0.908, 95% CI 0.839–0.978, <i>p</i> = 0.043) and reclassification (net reclassification improvement [NRI] 67.2%, <i>p</i> &#x3c; 0.001) to indicate futile recanalization. With respect to overall early complications, BCM+MMP-9+tenascin-C, BCM+MMP-9+CRP, BCM+MMP-9+ADAMTS13, BCM+tenascin-C+ADAMTS13, and BCM+CRP+ADAMTS13, all improved discrimination (AUC [95% CI]: 0.868 [0.766–0.970], 0.882 [0.773–0.990], 0.886 [0.788–0.984], 0.880 [0.783–0.977], and 0.863 [0.764–0.962], respectively, all <i>p</i> &#x3c; 0.05 by the DeLong method) and reclassification (NRI 59.1%, 71.8%, 51.1%, 67.4%, and 38.3%, respectively, all <i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> The increased levels of MMP-9, tenascin-C, CRP, thioredoxin, and decreased levels of ADAMTS13 and gelsolin were independent predictors of futile recanalization in AIS patients after recanalization by EVT.

ADAMTS13 activity is associated with early neurological improvement in acute ischemic stroke patients treated with intravenous thrombolysis

Although intravenous thrombolysis (IVT) with recombinant tissue-plasminogen-activator represents a highly effective treatment in acute ischemic stroke patients, not every patient benefits. We hypothesized that pretreatment levels of mediators of hemostasis (VWF and ADAMTS13) and dimethylarginines (ADMA and SDMA) are associated with early neurological improvement and outcome after IVT in ischemic stroke. Moreover we aimed to investigate the link between ADAMTS13 and markers of inflammation (CRP, IL-6, MMP-9 and MCP-1). In 43 patients with acute ischemic stroke treated with IVT blood samples for determination of the different markers were strictly taken before treatment, as well as at 24 h, 3, 7 and 90 days after symptom onset. Early neurological improvement was assessed using the shift between National Institutes of Health Stroke Scale (NIHSS) at baseline and at 24 h. Outcome at 90 days was assessed using the modified Rankin Scale. The lowest quartile of ADAMTS13 activity was independently associated with less improvement in NIHSS (baseline-24 h) (OR 1.298, p = 0.050). No independent association of ADMA or SDMA levels at baseline with outcome could be shown. Furthermore, IL-6, MCP-1 and CRP levels at 90 days significantly differed between patients with low and high ADAMTS13 activity. Thus, ADAMTS13 might indicate or even influence efficacy of IVT.

von Willebrand Factor Antigen, von Willebrand Factor Propeptide, and ADAMTS13 in Carotid Stenosis and Their Relationship with Cerebral Microemboli

BACKGROUND

 The relationship between von Willebrand factor antigen (VWF:Ag), VWF propeptide (VWFpp), VWFpp/VWF:Ag ratio, ADAMTS13 activity, and microembolic signal (MES) status in carotid stenosis is unknown.

METHODS

 This prospective, multicenter study simultaneously assessed plasma VWF:Ag levels, VWFpp levels and ADAMTS13 activity, and their relationship with MES in asymptomatic versus symptomatic moderate-to-severe (≥50-99%) carotid stenosis patients. One-hour transcranial Doppler ultrasound of the middle cerebral arteries classified patients as MES+ve or MES-ve.

RESULTS

 Data from 34 asymptomatic patients were compared with 43 symptomatic patients in the "early phase" (≤4 weeks) and 37 patients in the "late phase" (≥3 months) after transient ischemic attack (TIA)/ischemic stroke. VWF:Ag levels were higher (p = 0.049) and VWFpp/VWF:Ag ratios lower (p = 0.006) in early symptomatic than in asymptomatic patients overall, and in early symptomatic versus asymptomatic MES-ve subgroups (p ≤0.02). There were no intergroup differences in VWFpp expression or ADAMTS13 activity (p ≥0.05). VWF:Ag levels and ADAMTS13 activity decreased (p ≤ 0.048) and VWFpp/VWF:Ag ratios increased (p = 0.03) in symptomatic patients followed up from the early to late phases after TIA/stroke. Although there were no differences in the proportions of symptomatic and asymptomatic patients with blood group O, a combined analysis of early symptomatic and asymptomatic patients revealed lower median VWF:Ag levels in patients with blood group O versus those without blood group O (9.59 vs. 12.32 µg/mL, p = 0.035).

DISCUSSION

 VWF:Ag expression, a marker of endothelial ± platelet activation, is enhanced in recently symptomatic versus asymptomatic carotid stenosis patients, including in MES-ve patients, and decreases with ADAMTS13 activity over time following atherosclerotic TIA/ischemic stroke.

The Value of ADAMTS13 in Predicting Clinical Outcomes in Patients With Acute Ischemic Stroke Receiving Thrombolysis

Objective: To determine the association between baseline ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) antigen level and 90-days clinical outcome in patients with acute ischemic stroke (AIS) receiving recombinant tissue plasminogen activator (rt-PA) thrombolysis.

Methods: AIS patients receiving rt-PA thrombolytic therapy from Huashan Hospital and Fifth People's Hospital of Shanghai, China in 2014–2017 were consecutively enrolled. Blood samples for ADAMTS13 tests were drawn before intravenous rt-PA administration. The primary outcome was defined as the poor functional outcome of modified Rankin Scale (mRS) >2 at 90-days follow-up. Secondary outcome was hemorrhagic transformation after rt-PA therapy. Moreover, for AIS patients with large vessel occlusion from Huashan Hospital, the association between baseline ADAMTS13 level and cerebral collateral flow was also assessed.

Results: A total of 163 AIS patients (median age 66.2 years, 63.8% male) were included. Baseline ADAMTS13 level was marginally decreased in patients with 90-days mRS >2 than in those with mRS ≤ 2 (mean ± SD, 1458.4 ± 323.3 vs. 1578.3 ± 395.4 ng/mL, p = 0.046). However, no difference of ADAMTS13 level was found after adjusting for age, history of atrial fibrillation, glycemia, baseline NIHSS score and TOAST classification (p = 0.43). We found no difference in ADAMTS13 level between patients with parenchymal hemorrhage after rt-PA therapy and those without (p = 0.44). Among 66 patients with large vessel occlusion, there was also no association between ADAMTS13 level and cerebral collateral flow in multivariable analyses.

Conclusion: In our cohort, blood ADAMTS13 antigen level before rt-PA therapy could not be used as an independent biomarker in predicting clinical outcomes of AIS patients at 90 days.

Cerebral autoregulation and response to intravenous thrombolysis for acute ischemic stroke

We hypothesized that knowledge of cerebral autoregulation (CA) status during recanalization therapies could guide further studies aimed at neuroprotection targeting penumbral tissue, especially in patients that do not respond to therapy. Thus, we assessed CA status of patients with acute ischemic stroke (AIS) during intravenous r-tPA therapy and associated CA with response to therapy. AIS patients eligible for intravenous r-tPA therapy were recruited. Cerebral blood flow velocities (transcranial Doppler) from middle cerebral artery and blood pressure (Finometer) were recorded to calculate the autoregulation index (ARI, as surrogate for CA). National Institute of Health Stroke Score was assessed and used to define responders to therapy (improvement of ≥ 4 points on NIHSS measured 24–48 h after therapy). CA was considered impaired if ARI < 4. In 38 patients studied, compared to responders, non-responders had significantly lower ARI values (affected hemisphere: 5.0 vs. 3.6; unaffected hemisphere: 5.4 vs. 4.4, p = 0.03) and more likely to have impaired CA (32% vs. 62%, p = 0.02) during thrombolysis. In conclusion, CA during thrombolysis was impaired in patients who did not respond to therapy. This variable should be investigated as a predictor of the response to therapy and to subsequent neurological outcome.

Multilevel omics for the discovery of biomarkers and therapeutic targets for stroke

Despite many years of research, no biomarkers for stroke are available to use in clinical practice. Progress in high-throughput technologies has provided new opportunities to understand the pathophysiology of this complex disease, and these studies have generated large amounts of data and information at different molecular levels. The integration of these multi-omics data means that thousands of proteins (proteomics), genes (genomics), RNAs (transcriptomics) and metabolites (metabolomics) can be studied simultaneously, revealing interaction networks between the molecular levels. Integrated analysis of multi-omics data will provide useful insight into stroke pathogenesis, identification of therapeutic targets and biomarker discovery. In this Review, we detail current knowledge on the pathology of stroke and the current status of biomarker research in stroke. We summarize how proteomics, metabolomics, transcriptomics and genomics are all contributing to the identification of new candidate biomarkers that could be developed and used in clinical stroke management.

Thrombus heterogeneity in ischemic stroke

The structure of stroke thrombi has gained an increasing amount of interest in recent years. The advent of endovascular thrombectomy has offered the unique opportunity to provide and analyze thrombi removed from ischemic stroke patients. It has become clear that the composition of ischemic stroke thrombi is relatively heterogenous and various molecular and cellular patterns become apparent. Good understanding of the histopathologic characteristics of thrombi is important to lead future advancements in acute ischemic stroke treatment. In this review, we give a brief overview of the main stroke thrombus components that have been recently characterized in this rapidly evolving field. We also summarize how thrombus heterogeneity can affect stroke treatment.

Blood Biomarkers of Parenchymal Damage in Ischemic Stroke Patients Treated With Revascularization Therapies

Purpose

Postischemic reperfusion injury may exacerbate cerebral damage and capillary dysfunction, leading to brain edema (BE), hemorrhagic transformation (HT), necrosis, and injury from free radicals with subsequent infarct growth (IG). Several plasmatic biomarkers involved in the ischemic cascade have been studied in relation to radiological and clinical outcomes of reperfusion injury in ischemic stroke with heterogeneous results. This article provides a brief overview of the contribution of circulating biomarkers to the pathophysiology of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

Methods

We included full reports with measurements of plasma markers in patients with acute ischemic stroke treated with revascularization therapies.

Findings

Our research included a large number of observational studies investigating a possible role of circulating biomarkers in the development of parenchymal damage after acute stroke treatments. To make the results clearer, we divided the review in 4 sections, exploring the relation of different biomarkers with each of the indicators of parenchymal damage (HT, BE, IG, recanalization).

Discussion and conclusion

Definite conclusions are difficult to draw because of heterogeneity across studies. However, our review seems to confirm an association between some circulating biomarkers (particularly matrix metalloproteinase-9) and occurrence of parenchymal damage in ischemic stroke patients treated with revascularization therapies.

Blood Biomarkers for Stroke Diagnosis and Management

Biomarkers are objective indicators used to assess normal or pathological processes, evaluate responses to treatment and predict outcomes. Many blood biomarkers already guide decision-making in clinical practice. In stroke, the number of candidate biomarkers is constantly increasing. These biomarkers include proteins, ribonucleic acids, lipids or metabolites. Although biomarkers have the potential to improve the diagnosis and the management of patients with stroke, there is currently no marker that has demonstrated sufficient sensitivity, specificity, rapidity, precision, and cost-effectiveness to be used in the routine management of stroke, thus highlighting the need for additional work. A better standardization of clinical, laboratory and statistical procedures between centers is indispensable to optimize biomarker performance. This review focuses on blood biomarkers that have shown promise for translation into clinical practice and describes some newly reported markers that could add to routine stroke care. Avenues for the discovery of new stroke biomarkers and future research are discussed. The description of the biomarkers is organized according to their expected application in clinical practice: diagnosis, treatment decision, and outcome prediction.

Engineered microparticles and nanoparticles for fibrinolysis

Fibrinolytic agents including plasmin and plasminogen activators improve outcomes in acute ischemic stroke and thrombosis by recanalizing occluded vessels. In the decades since their introduction into clinical practice, several limitations of have been identified in terms of both efficacy and bleeding risk associated with these agents. Engineered nanoparticles and microparticles address some of these limitations by improving circulation time, reducing inhibition and degradation in circulation, accelerating recanalization, improving targeting to thrombotic occlusions, and reducing off-target effects; however, many particle-based approaches have only been used in preclinical studies to date. This review covers four advances in coupling fibrinolytic agents with engineered particles: (a) modifications of plasminogen activators with macromolecules, (b) encapsulation of plasminogen activators and plasmin in polymer and liposomal particles, (c) triggered release of encapsulated fibrinolytic agents and mechanical disruption of clots with ultrasound, and (d) enhancing targeting with magnetic particles and magnetic fields. Technical challenges for the translation of these approaches to the clinic are discussed.

ADAMTS13: An Emerging Target in Stroke Therapy

Thrombosis is the predominant underlying mechanism of acute ischemic stroke (AIS). Though thrombolysis with tPA has been proven to be effective in treating AIS within the time window, the majority of AIS patients fail to receive tPA due to various reasons. Current medical therapies for AIS have limited efficacy and pose a risk of intracerebral hemorrhage. ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13) is a metalloprotease that effectively breaks down the von Willebrand Factor (VWF), a key factor in thrombus formation. Previous studies have proven that dysfunction of ADAMTS13 is associated with many diseases. Recently, ADAMTS13 has been reported to be closely related to stroke. In this review, we briefly described the structure of ADAMTS13 and its role in thrombosis, inflammation, as well as angiogenesis. We then focused on the relationship between ADAMTS13 and AIS, ranging from ischemic stroke occurrence, to AIS treatment and prognosis. Based on research findings from in vitro, animal, and clinical studies, we propose that ADAMTS13 is a potential biomarker to guide appropriate treatment for ischemic stroke and a promising therapeutic agent for tPA resistant thrombi.

The role of plasminogen activators in stroke treatment: fibrinolysis and beyond

Although recent technical advances in thrombectomy have revolutionised acute stroke treatment, prevalence of disability and death related to stroke remain high. Therefore, plasminogen activators-eukaryotic, bacterial, or engineered forms that can promote fibrinolysis by converting plasminogen into active plasmin and facilitate clot breakdown-are still commonly used in the acute treatment of ischaemic stroke. Hence, plasminogen activators have become a crucial area for clinical investigation for their ability to recanalise occluded arteries in ischaemic stroke and to accelerate haematoma clearance in haemorrhagic stroke. However, inconsistent results, insufficient evidence of efficacy, or reports of side-effects in trial settings might reduce the use of plasminogen activators in clinical practice. Additionally, the mechanism of action for plasminogen activators could extend beyond the vessel lumen and involve plasminogen-independent processes, which would suggest that plasminogen activators have also non-fibrinolytic roles. Understanding the complex mechanisms of action of plasminogen activators can guide future directions for therapeutic interventions in patients with stroke.