Welcome to the ESOC 2021 Virtual Conference Calendar

Group Name

on behalf of the compoCLOT study group

Background And Aims

Recent studies have found that COVID-19 patients displayed resistance to fibrinolysis and that neutrophil extracellular traps (NETs) contributed to pulmonary microthrombotic complications of COVID-19. We aimed to analyze and compare AIS thrombi from COVID-19 and non COVID19 patients and to determine whether and how NETs played a role in their resistance to thrombolysis.

Methods

A total of 32 thrombi, recovered from COVID-19 AIS patients (N=15) or non-COVID-19 patients (N=17) and treated with endovascular therapy, were analyzed by immunohistology, RT-PCR, or subjected to ex vivo thrombolysis.

Results

All analyzed COVID-19 AIS thrombi were rich in neutrophils and NETs. SARS-CoV-2 RNA was not detected in the 3 COVID-19 positive analyzed thrombi. Ex vivo thrombolysis assay revealed a highly resistant pattern to tPA-induced thrombolysis in both groups. The addition of DNase 1 successfully reversed this thrombolysis resistance in a same proportion in both groups.

Conclusions

Our results identify NETs as important mediators of fibrinolysis resistance in patients with AIS independently of the COVID-19. NETs-targeting therapy with DNase 1 could offer a therapeutic opportunity to improve the efficacy of tPA in all AIS population regardless of the underlying AIS etiology.

Trial Registration Number

Not applicable

Background And Aims

We evaluated whether stroke severity, functional outcome and mortality are different in patients with ischemic stroke with or without COVID-19 infection.

Methods

A prospective, observational, multicentre cohort study in Catalonia, Spain. Recruitment was consecutive from mid-March to mid-May 2020. Patients had had an acute ischemic stroke within 48 hours and a previous modified Rankin scale (mRS) score of 0 to 3. We collected demographic data, vascular risk factors, prior mRS score, NIHSS score, rate of reperfusion therapies, logistics and metrics. Primary end-point was functional outcome at 3 months. Favourable outcome was defined depending on the previous mRS score. Secondary outcome was mortality at 3 months. We performed mRS shift and multivariate analyses.

Results

We evaluated 701 patients (mean age 72.3±13.3 years, 60.5% men), and 91 (13%) had COVID-19 infection. Median baseline NIHSS score was higher in COVID-19 patients compared to patients without COVID-19 [8 (3-18) vs 6 (2-14), p=0.049)]. Proportion of patients with a favourable functional outcome was 33.7% in the COVID-19 and 47% in the non-COVID-19 group. However, after a multivariate logistic regression analysis, COVID-19 infection did not increase the probability of unfavourable functional outcome. Mortality rate was 39.3% among COVID-19 patients and 16.1% in the non-COVID-19 group. In the multivariate logistic regression analysis, COVID-19 infection was a risk factor for mortality (HR 3.14 (95% CI, 2.10-4.71; p<0.001).

Conclusions

Patients with ischemic stroke and COVID-19 infection have more severe strokes and higher mortality than stroke patients without COVID-19 infection. However, functional outcome is comparable in both groups.

Trial Registration Number

Not applicable

Group Name

Investigators of the Swiss Stroke Registry

Background And Aims

Most case series of patients with ischemic stroke (IS) and COVID-19 are limited to random centers or lack 3-month outcome. The aim of this study is to describe prevalence, clinical, radiological and pathophysiological features and long-term outcome of COVID-19-related IS in a nationwide stroke registry.

Methods

From the Swiss Stroke Registry (SSR), we included all consecutive IS patients aged ≥18 years who were admitted to stroke units during the first wave of COVID-19 (25.02.-08.06.2020). We compared baseline features, stroke etiology and 3-month outcome (modified Rankin shift) of COVID PCR+ IS patients with COVID PCR- and/or asymptomatic non-tested IS patients.

Results

Of the 2376 IS patients entered in the SSR during the study period, 36 (1.5%) had confirmed COVID-19 infection (details in Figure 1).

In multivariate analysis, COVID+ patients had lower admission blood pressure (p=0.004) and more frequently lesions in multiple vascular territories (p=0.09). Stroke seemed more often related to several defined etiologies (p=0.07), and less often to large artery atherosclerotic (p=0.07) and cryptogenic mechanisms (p=0.03). There was a strong trend towards worse outcome in COVID+ patients across the entire Rankin-spectrum (Figure 2) despite adjustment for age, stroke severity and revascularization treatments (OR 1.97, 95%CI 0.92-4.21, p=0.08).

Conclusions

In this nationwide analysis of consecutive ischemic strokes, concomitant COVID-19 was relatively rare. COVID+ patients more often had multiple territory involvement and multiple stroke mechanisms, and their 3-month outcome was worse across the entire Rankin spectrum.

Trial Registration Number

N/A

Background And Aims

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine recruiting monocytes to the atherosclerotic plaque. Experimental, epidemiological and genetic data support a key role of MCP-1 in atherosclerosis. Yet, the translational potential of targeting MCP-1 signaling for lowering vascular risk is limited by the lack of data on plaque MCP-1 activity in human atherosclerosis.

Methods

We measured MCP-1 in human plaque samples from 1,199 patients undergoing carotid endarterectomy from the Athero-Express Biobank. We explored associations of plaque MCP-1 levels with histopathological features of plaque vulnerability, clinical plaque instability (symptomatic vs. asymptomatic plaque), molecular markers of plaque inflammation and remodeling, and incident vascular events up to three years after plaque removal.

Results

Plaque MCP-1 levels were associated with histopathological hallmarks of plaque vulnerability (large lipid core, low collagen, high macrophage content, low smooth muscle cell content, intraplaque hemorrhage), as well as with a cumulative vulnerability index (range 0-5, beta: 0.42, 95%CI: 0.30-0.53, p=5.4x10^-13) independently of age, sex, and conventional vascular risk factors. Furthermore, MCP-1 levels were higher among in symptomatic versus asymptomatic plaques (p=0.0001. Plaque MCP-1 was associated with pro-inflammatory cytokines involved in leukocyte adhesion and matrix metalloproteinase activity in the plaque. In the follow-up analyses, MCP-1 levels were associated with a higher risk of peri-procedural events (up to 30 days after surgery).

Conclusions

Our findings highlight a role of MCP-1 in human plaque vulnerability, the leading mechanism underlying vascular events like stroke and myocardial infarction. As such, they suggest that interfering with MCP-1 signaling in patients with established atherosclerosis could lower vascular risk.

Background And Aims

Neuroinflammation has been recognized as potential pathogenic mechanisms for cerebral small vessel disease (SVD). This study aims to explore the role of soluble form of triggering receptor expressed on myeloid cells 2 (sTREM2), a marker for microglia activation, in SVD.

Methods

10 AD patients (age 75.6 ±8.1 years) and 66 ICH survivors consisting of 20 with CAA (age 71.1 ± 9.8 years) and 46 with hypertensive SVD (age 63.1 ± 11.3 years) were enrolled. Each participant received examination for plasma levels of sTREM2. Brain MRI and 11C-Pittsburg compound B PET were performed. Patients of amyloid related disease including AD and CAA also received 18F-T807 PET for measuring cortical tau burden.

Results

Plasma sTREM2 levels were not different between AD and SVD (8.75 [6.08-10.79] vs 8.13 [6.938-10.19] ng/mL, p=0.690). In SVDs, sTREM2 levels were significantly associated with white matter hyperintensity (WMH) volume (r=0.49, p<0.001), but not to cerebral amyloid load or other markers of neurodegeneration. The associations of sTREM2 and WMH volume remained significant (p<0.001) after adjustment for age and sex, and were also independent of vascular Aβ burden or SVD subtype. In amyloid-related diseases including AD and CAA, sTREM2 levels were elevated in Tau PET(+) compared to Tau PET(-) patients (9.96 [8.50-14.76] vs 7.45 [6.55-7.76] ng/mL, p=0.002). In multivariate analysis, sTREM2 level was independently associated with positive tau scan (p=0.001) and WMH volume (p=0.018), but not to their amyloid load (p=0.277).

Conclusions

Our findings suggest both progressive white matter injury and AD-related tau pathology could activate microglia-associated neuroinflammation in SVD.

Background And Aims

The CC-chemokine ligand 2 (CCL2) regulates monocyte recruitment to atherosclerotic lesions via CC-chemokine receptor 2 (CCR2) binding. Data from mouse models along with explorations in humans strongly indicate a causal involvement of the CCL2/CCR2 axis in atherosclerosis. Still, the potential of targeting the CCL2/CCR2 axis for preventing manifestations of atherosclerotic disease remains under question. Here, we explored whether therapeutic inhibition of CCL2 or CCR2 in atheroprone mouse models confers atheroprotection and plaque stability.

Methods

We conducted a systematic literature review, which returned 14 studies that tested the inhibition of the CCL2/CCR2 axis in mouse models of atherosclerosis. We then performed meta-analyses of plaque size, macrophage accumulation, collagen deposition, and smooth-muscle content. Subgroup and meta-regression analyses were conducted to explore sources of heterogeneity.

Results

CCL2/CCR2 blockade attenuated atherosclerotic lesion size in the aortic root or arch (g=-0.75 [-1.17; -0.32], p=6×10^-4), the carotid (g=-2.39 [-4.23; -0.55], p=0.011) and the femoral artery (g=-2.38 [-3.50; -1.26], p=3×10^-5). CCL2/CCR2 inhibition reduced macrophage accumulation, increased smooth muscle cell content, and enhanced collagen deposition, indicative of a plaque-stabilizing effect. The effects of CCL2/CCR2 inhibition on lesion size correlated with the effects on macrophage accumulation, corroborating the role of CCL2/CCR2 signaling in monocyte recruitment. There were no differences in effects on lesion size and macrophage accumulation by lesion stage or inhibition target.

Conclusions

Targeting either CCL2 or CCR2 mitigates atherosclerosis throughout the vasculature and improves plaque characteristics in atheroprone mice. These findings underline the translational potential of targeting CCL2/CCR2 signaling in atherosclerotic disease, which remains to be tested in clinical trials.

Background And Aims

In ischemic stroke (IS), impairment of the blood-brain barrier (BBB) plays an important role in the development of neurological dysfunction. BBB disruption, which is associated with inflammatory responses, is responsible for unfavorable outcomes and adverse treatment effects like intracranial hemorrhages. During the processes of inflammation, endothelial cells (EC) may play a critical role in the enhancement of inflammatory responses and EC death may initiate brain damage.

Methods

We used brain ECs, exposed them to oxygen and glucose deprivation (OGD) in vitro and measured their survival depending on an inflammasome inhibition with the NLRP3 specific inhibitor MCC950. Translationally, IS was induced in C57Bl/6 mice by 60 minutes transient middle cerebral artery occlusion and 1 d of reperfusion with and without MCC950 treatment.

Results

During OGD, the survival of the ECs could be significantly improved by NLRP3 blockage while the cellular NLRP3 expression was simultaneously reduced. Furthermore, MCC950 lead to reduced levels of Caspase 1 (p20) as well as activated Gasdermin D as markers for pyroptosis. Moreover, pro-inflammatory chemokines and MMP9 were reduced after inflammasome inhibition. In the murine model stroke volumes, functional outcome, the BBB integrity, and - in good agreement with the in vitro results - MMP9 secretion as well as the rate of endothelial cell death within the vascular compartment improved significantly after MCC950 application.

Conclusions

In conclusion, our results establish the NLRP3 inflammasome as a critical pathogenic effector of stroke induced BBB disruption by mediating inflammatory signaling cascades and pyroptosis in brain ECs.

Trial Registration Number

N/A

Background And Aims

¹⁸F-fluorodeoxyglucose positron-emission tomography (¹⁸FDG-PET) identifies carotid plaque inflammation in vivo. We sought to determine plasmatic inflammatory biomarkers associated with plaque inflammation imaged by ¹⁸FDG-PET.

Methods

We conducted a prospective study (2016-2019) of consecutive patients with recent (<7 days) anterior circulation ischemic stroke and at least one atherosclerotic plaque in the ipsilateral internal carotid artery. Cardioembolic strokes were excluded. All of the patients underwent a carotid ¹⁸FDG-PET. A blood sample was obtained from all of the patients. Plasma concentration of several inflammatory molecules was analyzed in a Luminex using xMAP® technology with a MILLIPLEX® MAP multiplexed assay kit (Merck Millipore). Linear regression was used to test association between plasmatic biomarkers and ¹⁸FDG Standardized Uptake Value. Cox regression was used to test association between biomarkers and stroke recurrence.

Results

We included 54 patients with a mean age of 75.2±9.8 and 14 (25.9%) were women. There were 30 (55.6%) patients with a carotid stenosis ³50% and the reminder presented stenosis <50%. We analysed 16 different inflammatory biomarkers. In multivariable linear regression analysis (adjusted for degree of stenosis) plasma concentration of soluble Intercellular Adhesion Molecule-1 (sICAM-1) was the only biomarker independently associated with plaque inflammation (β=0.13, 95%CI 0.06-0.19; p<0.001). Remarkably, in multivariable Cox regression analysis sICAM-1 concentration at the highest tercile was associated with stroke recurrence after adjustment for age and degree of stenosis (HR=4.62, 95%CI 1,01-21,13; p=0.043).

Conclusions

Elevated concentrations of sICAM-1 were associated with carotid plaque inflammation and increased risk of stroke recurrence in patients with recent ischemic stroke and carotid atherosclerosis.

Trial Registration Number

N/A