Stroke Infarct Volume Research Articles

Correlation between ASPECTS and Core Volume on CT Perfusion: Impact of Time since Stroke Onset and Presence of Large-Vessel Occlusion.

Both ASPECTS and core volume on CTP are used to estimate infarct volume in acute ischemic stroke. To evaluate the potential role of ASPECTS for acute endovascular treatment decisions, we studied the correlation between ASPECTS and CTP core, depending on the timing and the presence of large-vessel occlusion. We retrospectively reviewed all MCA acute ischemic strokes with standardized reconstructions of CTP maps entered in the Acute STroke Registry and Analysis of Lausanne (ASTRAL) registry. Correlation between ASPECTS and CTP core was determined for early (<6 hours) versus late (6-24 hours) times from stroke onset and in the presence versus absence of large-vessel occlusion. We used correlation coefficients and adjusted multiple linear regression models. We included 1046 patients with a median age of 71.4 years (interquartile range, IQR = 59.8-79.4 years), an NIHSS score of 12 (IQR, 6-18), an ASPECTS of 9 (IQR, 7-10), and a CTP core of 13.6 mL (IQR, 0.6-52.8 mL). The overall correlation between ASPECTS and CTP core was moderate (ρ = -0.49, P < .01) but significantly stronger in the late-versus-early window (ρ = -0.56 and ρ = -0.48, respectively; P = .05) and in the presence versus absence of large-vessel occlusion (ρ = -0.40 and ρ = -0.20, respectively; P < .01). In the regression model, the independent association between ASPECTS and CTP core was confirmed and was twice as strong in late-arriving patients with large-vessel occlusion (β = -0.21 per 10 mL; 95% CI, -0.27 to -0.15; P < .01) than in the overall population (β = -0.10; 95% CI, -0.14 to -0.07; P < .01). In a large cohort of patients with acute ischemic stroke, we found a moderate correlation between ASPECTS and CTP core. However, this was stronger in patients with large-vessel occlusion and longer delay from stroke onset. Our results could support the use of ASPECTS as a surrogate marker of CTP core in late-arriving patients with acute ischemic stroke with large-vessel occlusion.

Ischemic lesion volume prediction in thrombolysis treated wake-up stroke patients

There is growing research interest on identification of CT Perfusion (CTP) parameters that predict the outcome in acute ischemic stroke patients. The aim of this study is to produce the model, based on core-penumbra related parameters assessed by CTP processing and commonly used clinical prediction factors, to predict the final infarct volume in thrombolysis-treated anterior circulation wake-up stroke (WUS) patients. The study was conducted on 51 consecutive wake-up ischemic stroke patients. The model for the predictive estimation of final ischemic volume was determined by using the Least Absolute Shrinkage and Selection Operator (LASSO) regularized least-squares regression. The results showed that CTP core volume and CTP total ischemic volume at admission, together with ASPECT score predict the final infarct lesion volume. In particular, the identified model presented 5-fold cross-validation root mean square error RMSE of 8.1 ml and the coefficient of determination (R2=0.94) on our dataset. The results should be confirmed in a lager study. In conclusion, in this study we preliminarily identified a predictive model to estimate final ischemic lesion volume in thrombolysis treated wake-up stroke patients.

Infarct volumes of patients with acute ischemic stroke receiving direct oral anticoagulants due to non-valvular atrial fibrillation

Direct oral anticoagulants (DOACs) have been shown to decrease the risk of ischemic stroke in non-valvular atrial fibrillation (NVAF). This study aims to investigate whether DOACs result in a significant change in lesion volume and the severity of the subsequent disability in patients who have experienced a stroke.Methods:The study included a total of 137 patients with NVAF and acute stroke. The cohort included 76 patients using DOACs, 21 patients using acetylsalicylic acid (ASA), and 40 patients with newly diagnosed atrial fibrillation (NDAF) who did not use antiaggregants or anticoagulants. Diffusion-weighted MRI was performed 6–12 hours after the first stroke symptoms and infarct volumes were measured by two independent observers. Baseline National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale (mRS) score at discharge and period of hospitalization were calculated.Results:When patients using DOACs due to NVAF and patients with NDAF were compared, the volumes of patients using DOACs (median 7.8 vs 23.1 cm3; P ≤ 0.01) were statistically significantly smaller. However, there was no difference in volume between ASA users (median 16.9 cm3; P = 0.16) and patients with NDAF. The DOACs group was significantly different compared to the NDAF group in terms of NIHSS scores (median 4.4 vs 8.3; P ≤ 0.01) and mRS scores at discharge (median 1.7 vs 2.7; P ≤ 0.01), and period of hospitalization (median 6.4 vs 10.4 days; P ≤ 0.01).Conclusion:We observe, while using DOACs, the infarct volumes of patients who experience stroke are smaller than those with NDAF and using ASA, as well as mRS scores at discharge are low and length of hospital stay is short.

Ischemic stroke disrupts the endothelial glycocalyx through activation of proHPSE via acrolein exposure

Infiltration of peripheral immune cells after blood-brain barrier dysfunction causes severe inflammation after a stroke. Although the endothelial glycocalyx, a network of membrane-bound glycoproteins and proteoglycans that covers the lumen of endothelial cells, functions as a barrier to circulating cells, the relationship between stroke severity and glycocalyx dysfunction remains unclear. In this study, glycosaminoglycans, a component of the endothelial glycocalyx, were studied in the context of ischemic stroke using a photochemically induced thrombosis mouse model. Decreased levels of heparan sulfate and chondroitin sulfate and increased activity of hyaluronidase 1 and heparanase (HPSE) were observed in ischemic brain tissues. HPSE expression in cerebral vessels increased after stroke onset and infarct volume greatly decreased after co-administration of N-acetylcysteine + glycosaminoglycan oligosaccharides as compared with N-acetylcysteine administration alone. These results suggest that the endothelial glycocalyx was injured after the onset of stroke. Interestingly, scission activity of proHPSE produced by immortalized endothelial cells and HEK293 cells transfected with hHPSE1 cDNA were activated by acrolein (ACR) exposure. We identified the ACR-modified amino acid residues of proHPSE using nano LC–MS/MS, suggesting that ACR modification of Lys139 (6-kDa linker), Lys107, and Lys161, located in the immediate vicinity of the 6-kDa linker, at least in part is attributed to the activation of proHPSE. Because proHPSE, but not HPSE, localizes outside cells by binding with heparan sulfate proteoglycans, ACR-modified proHPSE represents a promising target to protect the endothelial glycocalyx.

Abstract 12527: Serum Amyloid A, Inflammasome Activation and Stroke

Serum amyloid A (SAA) proteins are critical to the regulation of inflammation in systemic as well as neurological diseases. Studies have shown that during an acute phase response (APR), SAA levels increase 1000-fold and can stimulate the inflammasome, trigger the recruitment of immune cells to inflammatory sites, and elicit the induction of enzymes that degrade extracellular matrix. Our long-term goal is to dissect the mechanisms regulating SAA function, particularly the contribution to stroke related damage. Recent studies have demonstrated that activation of the inflammasome is a critical event in stroke progression in mice. The central hypothesis is that SAA activates the NLRP3 inflammasome, and amplifying the local inflammatory responses that enhance neuronal cell death and stroke progression. We show that activation of the NLRP3 inflammasome by SAA exacerbates stroke in mice. Using mice deficient in SAA, RAGE and various inflammasome components (cathepsin B, NLRP3, ASC, caspase-1 and IL-1beta) or IL-1R mice, we demonstrated that SAA-mediated stroke outcomes are dependent on the NLRP3 inflammasome. In addition, using microglial cell cultures, we determined the impact of SAA on RAGE mediated pathologies (ROS generation, etc.) as well as the influence of SAA-HDL on SAA-mediated NLRP3 activation. We tested the hypothesis that systemic SAA exacerbates the progression of neuronal cell death and inflammation in stroke. We showed that SAA deficient mice determined the impact on stroke infarct volume and outcomes. In addition, using viral vectors to express SAA as well as an inducible transgene help us determine the role of SAA with specific expression of SAA. The impact of SAA on inflammation, neuronal cell death, matrix remodeling, etc. was attenuated in SAA deficient mice. In addition, we demonstrated the role of SAA and the inflammasome in human stroke, and the relationship between plasma SAA, IL-1beta and the impact on stroke outcomes.

Quercitrin inhibits platelet activation in arterial thrombosis

BackgroundThe ingestion of flavonoids has been reported to be associated with reduced cardiovascular disease risk. Quercitrin is a common flavonoid in nature, and it exhibits antioxidant properties. Although the process of thrombogenesis is intimately related to cardiovascular disease risk, it is unclear whether quercitrin plays a role in thrombogenesis. PurposeThe aim of this study was to examine the antiplatelet effect of quercitrin in platelet activation. MethodsPlatelet aggregation, granule secretion, calcium mobilization, and integrin activation were used to assess the antiplatelet activity of quercitrin. Antithrombotic effect was determined in mouse using ferric chloride (FeCl3)-induced arterial thrombus formation in vivo and thrombus formation on collagen-coated surfaces under arteriolar shear in vitro. Transection tail bleeding time was used to evaluate whether quercitrin inhibited primary hemostasis. ResultsQuercitrin significantly impaired collagen-related peptide-induced platelet aggregation, granule secretion, reactive oxygen species generation, and intracellular calcium mobilization. Outside-in signaling of αIIbβ3 integrin was significantly inhibited by quercitrin in a concentration-dependent manner. The inhibitory effect of quercitrin resulted from inhibition of the glycoprotein VI-mediated platelet signal transduction during cell activation. Further, the antioxidant effect is derived from decreased phosphorylation of components of the TNF receptor-associated factor 4/p47phox/Hic5 axis signalosome. Oral administration of quercitrin efficiently blocked FeCl3-induced arterial thrombus formation in vivo and thrombus formation on collagen-coated surfaces under arteriolar shear in vitro, without prolonging bleeding time. Studies using a mouse model of ischemia/reperfusion-induced stroke indicated that treatment with quercitrin reduced the infarct volume in stroke. ConclusionsOur results demonstrated that quercitrin could be an effective therapeutic agent for the treatment of thrombotic diseases.

Spatial Resolution and the Magnitude of Infarct Volume Measurement Error in DWI in Acute Ischemic Stroke.

Infarct volume in acute ischemic stroke is an important prognostic marker and determines endovascular treatment decisions. This study evaluates the magnitude and potential clinical impact of the error related to partial volume effects in infarct volume measurement on diffusion-weighted MR imaging in acute stroke and explores how increasing spatial resolution could reduce this error. Diffusion-weighted imaging of 393 patients with acute stroke, of whom 56 had anterior circulation large-vessel occlusion, was coregistered to standard space. Lesion boundaries were manually segmented. A 3D lesion-volume model was resampled for voxel sizes from 4 × 4 × 8 to 1 × 1 × 2 mm, and the surface-volume, corresponding to the partial volume error, was calculated. The number of cases with anterior circulation large-vessel occlusion, in which the endovascular therapy core threshold of 70 mL was contained within the margin of error, was calculated as a function of imaging resolution. The mean infarct core volume was 27.2 ± 49.9 mL. The mean surface volume was 14.7 ± 20.8 mL for 2 × 2 × 4 mm resolution and 7.4 ± 10.7 mL for 1 × 1 × 2 mm resolution. With a resolution of 2 × 2 × 4 mm, 70 mL was contained within the margin of error in 7/56 cases (12.5%) with large-vessel occlusion, while with a 1 × 1 × 2 mm voxel size, the margin of error was 3/56 (5%). The lesion-volume range of potentially misclassified lesions dropped from 46.5-94.1 mL for a 2 × 2 × 4 mm resolution to 64.4-80.1 mL for a 1 × 1 × 2 mm resolution. Partial volume effect is an important source of error in infarct volume measurement in acute stroke. Increasing spatial resolution substantially decreases the mean error. Standard use of high-resolution DWI should be considered to increase the reliability of infarct volume measurements.

Effect of Prestroke Glycemic Variability Estimated Glycated Albumin on Stroke Severity and Infarct Volume in Diabetic Patients Presenting With Acute Ischemic Stroke.

Background: We investigated whether prestroke glycemic variability, represented by glycated albumin (GA), affects the initial stroke severity and infarct volume in diabetic patients presenting with acute ischemic stroke.Methods: We evaluated a total of 296 acute ischemic stroke patients with diabetes mellitus who were hospitalized within 48 h of stroke onset. GA was measured in all acute ischemic stroke patients consecutively during the study period. The primary outcome was the initial National Institute Health Stroke Scale (NIHSS) score. The secondary outcome was infarct volume on diffusion-weighted imaging, which was performed within 24 h of stroke onset. Higher GA (≥16.0%) was determined to reflect glycemic fluctuation prior to ischemic stroke.Results: The number of patients with higher GA was 217 (73.3%). The prevalence of a severe initial NIHSS score (>14) was higher in patients with higher GA than in those with lower GA (3.8% vs. 15.7%, p = 0.01). The proportion of participants in the highest quartile of infarct volume was higher in the higher GA group (11.4% vs. 36.4%, p < 0.001). A multivariable analysis showed that higher GA was significantly associated with a severe NIHSS score (odds ratio, [95% confidence interval], 7.99 [1.75–36.45]) and large infarct volume (3.76 [1.05–13.45]).Conclusions: Prestroke glucose variability estimated by GA was associated with an increased risk of severe initial stroke severity and large infarct volume in acute ischemic stroke patients with diabetes mellitus.

Platelet necrosis mediates ischemic stroke outcome in mice

AbstractDysregulated platelet functions contribute to the development and progression of ischemic stroke. Utilizing mice with a platelet-specific deletion of cyclophilin D (CypD), a mediator of necrosis, we found that platelet necrosis regulates tissue damage and outcomes during ischemic stroke in vivo. Mice with loss of CypD in platelets (CypDplt−/−mice) exhibited significantly enhanced cerebral blood flow, improved neurological and motor functions, and reduced ischemic stroke infarct volume after cerebral ischemia-reperfusion injury. These effects were attributable, at least in part, to platelet-neutrophil interactions. Twenty-four hours after stroke, significantly more circulating platelet-neutrophil aggregates (PNAs) were found in CypDplt+/+ mice. Underscoring the role of platelet necrosis in PNA formation, we observed a significant number of phosphatidylserine (PS)+ platelets in PNAs in CypDplt+/+ mice. In contrast, significantly fewer platelets in PNAs were PS+ in CypDplt−/− counterparts. Accordingly, mice with CypD-deficient platelets had fewer neutrophils and PNAs recruited to their brain following stroke relative to wild-type counterparts. Neutrophil depletion in wild-type mice conferred protection from ischemic stroke to a similar degree as observed in mice with CypD-deficient platelets. Neutrophil depletion in CypDplt−/− mice did not further reduce infarct size. Transmission electron microscopy of ex vivo–formed PNAs revealed a propensity of necrotic platelets to interact with neutrophils. These results suggest that necrotic platelets interact with neutrophils to exacerbate brain injury during ischemic stroke. Because inhibiting platelet necrosis does not compromise hemostasis, targeting platelet CypD may be a potential therapeutic strategy to limit brain damage following ischemic stroke.

Abstract WP315: Neuroprotective Effects of Endogenous Adropin in Experimental Ischemic Stroke

Adropin is an endogenous peptide highly expressed in the brain and is encoded by the energy homeostasis-associated gene, Enho . We recently found that treatment with synthetic adropin peptide reduces infarct volume in ischemic stroke. This protection by exogenous adropin is associated with a significant increase in endothelial nitric oxide synthase (eNOS) phosphorylation (Ser 1176 ) and reduction of blood-brain barrier (BBB) permeability. However, it is not known whether endogenous adropin modulates ischemic brain damage. We hypothesize that lack of brain adropin increases stroke damage by exacerbating neurovascular dysfunction, while overexpression of this peptide decreases ischemic brain injury. We measured infarct size and BBB damage in male and female adropin overexpressing transgenics (AdrTg), adropin knockout ( Enho -/- ), and corresponding wild-type (WT) control mice subjected to permanent middle cerebral artery occlusion (pMCAO). At 48h after stroke, infarct volume was significantly smaller in AdrTg mice of both sexes compared to WT controls, while stroke resulted in a much larger infarction in both male and female Enho -/- compared to Enho +/+ mice. Brain levels of IgG and albumin, two sensitive markers of BBB disruption, were significantly reduced in AdrTg mice compared to the WT group, while the levels of these two plasma proteins in the ischemic brain of Enho -/- mice were dramatically increased compared to Enho +/+ animals after stroke. Latex vessel casting showed no differences in cerebrovascular anatomy or the diameter of the main brain arteries between Enho -/- , AdrTg and their respective WT controls. In AdrTg mice, we found a positive correlation between brain adropin levels and eNOS phosphorylation. These data suggest that increased eNOS phosphorylation by adropin is a potential mechanism underlying its protective effects in stroke. Consistent with this hypothesis, the protective effects of adropin were completely abolished in eNOS knockout (eNOS -/- ) mice subjected to pMCAO. Taken together, our findings show for the first time that endogenous adropin is a neuroprotective peptide in ischemic stroke. Understanding adropin signaling and function could offer a novel therapeutic strategy for the treatment of ischemic brain damage.

Abstract 176: Platelet Cyclophilin D Mediates Neutrophil Recruitment and Ischemic Stroke Outcomes in Mice

Rationale: Besides their role in thrombosis, platelets also mediate inflammation through platelet-neutrophil aggregates (PNA). Recently, cyclophilin D (CypD)-mediated platelet necrosis emerged as a potential mediator of detrimental PNA during thrombosis. However, the role of platelet CypD in ischemic stroke has never been examined. Objective: Here, we investigate the contribution of platelet CypD following ischemic stroke. Methods: We generated mice lacking CypD specifically in platelets (KO). Both wild-type (WT) and KO mice were subjected to a 1h transient middle cerebral artery occlusion (tMCAO) stroke model. Twenty-four hours after occlusion, neurological and motor function, and stroke infarct size were determined. We also examined if the CypD pathway was altered in human platelets after ischemic stroke. Results: Loss of platelet CypD significantly improved neurological (p&lt;0.001) and motor (p&lt;0.005) functions compared to WT mice after tMCAO. Furthermore, platelet CypD deficient significantly reduced ischemic stroke infarct volume (39.1±15.7mm 3 vs. 78.6±27.7mm 3 , n=15; p&lt;0.0001). Smaller infarcts in KO mice was not due to difference in blood flow during the ischemia stage. Twenty-four hours after stroke, a greater than 2-fold reduction in neutrophils was observed in the brains from KO mice (p&lt;0.0001). In addition, we observed significantly fewer circulating and cerebral PNA (p&lt;0.01). Depletion of neutrophils significantly (p&lt;0.05) reduced infarct size and neurological damage following ischemic stroke in WT mice, however, no additional protective effect was observed in KO mice, suggesting necrotic PNAs are critical during ischemic stroke. RNA-sequencing on platelets isolated from ischemic stroke patients (n=8) and healthy aged, gender matched controls (n=7) revealed significant increases in several targets involved in CypD-mediated necrosis, including MCUR1, TMEM16F and calpain2 (p&lt;0.005). Conclusion: Our results demonstrate necrotic platelets interact with neutrophils to exacerbate brain injury following ischemic stroke. As inhibiting platelet necrosis does not compromise hemostasis, targeting platelet CypD may be a potential therapeutic strategy to limit brain damage after ischemic stroke.

Relationship between elevated plasma trimethylamine N-oxide levels and increased stroke injury.

To investigate whether elevated plasma trimethylamine N-oxide (TMAO) levels are associated with initial stroke severity and infarct volume. This cross-sectional study included 377 patients with acute ischemic stroke and 50 healthy controls. Plasma TMAO levels were assessed at admission. Stroke infarct size and clinical stroke severity were measured with diffusion-weighted imaging and the NIH Stroke Scale (NIHSS). Mild stroke was defined as an NIHSS score <6. Plasma TMAO levels were higher in patients with ischemic stroke than in healthy controls (median 5.1 vs 3.0 μmol/L; p < 0.001). Every 1-µmol/L increase in TMAO was associated with a 1.13-point increase in NIHSS score (95% confidence interval [CI] 1.04-1.29; p < 0.001) and 1.69-mL increase in infarct volume (95% CI 1.41-2.03; p < 0.001) after adjustment for vascular risk factors. At admission, 159 patients (42.2%) had experienced a mild stroke, and their plasma TMAO levels were lower compared to those with moderate to severe stroke (median 3.6 vs 6.5 µmol/L; p < 0.001). The area under the receiver operating characteristics curve of plasma TMAO level in predicting moderate to severe stroke was 0.794 (95% CI 0.748-0.839; p < 0.001), and the optimal cutoff value was 4.95 μmol/L. The sensitivity and specificity of TMAO levels ≥4.95 μmol/L for moderate to severe stroke were 70.2% and 79.9%, respectively. Patients with ischemic stroke had higher plasma TMAO levels compared to healthy controls. Higher plasma TMAO level at admission is an independent predictor of stroke severity and infarct volume in patients with acute ischemia.

Diagnostic Value of Serum hsa_circ_0141720 in Patients with Acute Ischemic Stroke.

The current study aims to observe the expression of hsa_circ_0141720 in the serum of patients with acute cerebral infarction (ACI) and to explore its clinical value in the diagnosis of ACI. Eighty patients with ACI within the previous 48 hours were selected, and 30 healthy persons in the same period were selected as the control. Microarray analysis was performed to evaluate the changes of circRNA profiles, and RT-PCR was used to validate the findings. Pearson's correlation assay was performed to analyze the correlation between the level of hsa_circ_0141720 and other clinical indicators. Microarray analysis identified eight differentially expressed cirRNAs in the serum of ACI patients. RT-PCR validated that the expression of hsa_circ_0141720 in serum of ACI patients was increased the most. Hence, we mainly focused on hsa_circ_0141720 in the following study. ROC curve analysis showed that when the cutoff value for serum hsa_circ_0141720 was 2.03, the sensitivity and specificity were 89.7% and 95.6%, respectively. Further study showed that enhanced hsa_circ_0141720 expression was positively correlated with the National Institutes of Health Stroke Scale (NIHSS) scores and infarct volume of ACI patients. Moreover, upregulation of hsa_circ_0141720 was also positively correlated with increased expression of serum interleukin 6 (IL-6) and plasma high-sensitivity C relative protein (hs-CRP) in patients with ACI. In summary, enhanced expression of hsa_circ_0141720 in the serum of patients with ACI was related to the severity of the disease and it may be used as a new serological index for the diagnosis of ACI.

Cyclophilin D Mediated Platelet Necrosis Regulates Ischemic Stroke Outcomes in Mice

Background: Anti-platelet agents are used clinically to prevent ischemic stroke but are incompletely effective. Emerging evidence highlights that platelets contribute to ischemic stroke through mechanisms and pathways that are not targeted by classic anti-platelet agents. Besides their role in thrombosis, platelets also mediate inflammation through the formation of heterotypic leukocyte aggregates. In particular, platelet-neutrophil interactions are known to promote brain injury following ischemic stroke. However, the mechanism by which platelets interact with neutrophils and promote thromboinflammation in ischemic stroke remains elusive. Recently, cyclophilin D (CypD)-mediated platelet necrosis emerged as a potential mediator of detrimental platelet-neutrophil interactions. Aims: To investigate the role of CypD-mediated platelet necrosis in the setting of acute ischemic stroke. Methods: Mice harboring a floxed allele of CypD were crossed to animals expressing Cre recombinase controlled by the Pf4 promoter to generate platelet-specific CypD deficient mice (KO). KO mice and littermate controls (WT)were subjected to a transient middle cerebral artery occlusion (tMCAO) model with 1h of cerebral ischemia followed by 23h of reperfusion or a permanent MCAO model with 24h of ischemia. Neurological and motor outcomes and brain infarct size were measured 24h after stroke onset. In addition, we examined both circulating and cerebral platelet-neutrophil aggregates 24h after stroke. Cerebral blood flow was monitored via blood laser doppler flowmetry. Neutrophils were depleted 24h before stroke onset using a neutrophil-depleting antibody to examine the contribution of neutrophils in ischemic stroke. Results: Loss of CypD in platelets significantly improved neurological (p&amp;lt;0.001) and motor (p&amp;lt;0.005) functions and reduced ischemic stroke infarct volume (p&amp;lt;0.0001) after cerebral transient ischemia/reperfusion injury compared to WT controls. To determine whether improved stroke outcomes in KO mice was associated with improved local cerebral blood flow (CBF) during reperfusion, CBF was measured at time points during and after stroke induction. During ischemia, and immediately after reperfusion, CBF was similar in WTand KO mice. Nevertheless, 3h after stroke onset, CBF was significantly greater (48±15% vs 31±10%; p&amp;lt;0.05) in KO mice compared to WTmice. This difference in CBF persisted and was even more pronounced at 24h (54±12% vs 27±8%; p&amp;lt;0.01). To further investigate whether platelet necrosis was contributing to brain infarction during cerebral reperfusion, we employed a permanent MCAO model. With permanent occlusion, no differences were observed in infarct volume, neurological functions, or motor functions between WT or KO mice, suggesting platelet CypD specifically mediates reperfusion injury following transient cerebral ischemia. These detrimental effects of platelet necrosis were attributable, in part, to platelet-neutrophil interactions. Twenty-four hours after stroke, significantly (p&amp;lt;0.01) fewer circulating platelet-neutrophil aggregates were found in KO mice. Underscoring the role of platelet necrosis in this process, we observed that 33±4% of platelets in platelet-neutrophil aggregates expressed phosphatidylserine (PS) on their surface in WTmice. In contrast, only 17.8±5.1% of platelets in platelet-neutrophil aggregates were PS-positive in KO counterparts (p&amp;lt;0.01). Furthermore, KO mice had less neutrophils recruited to their brain relative to WT controls, and cerebral platelet-neutrophil aggregates were virtually absent in KO mice. To determine whether the protective effect observed in KOmice was due to reduced interactions between necrotic platelets and neutrophils, we depleted circulating neutrophils 24h before induction of stroke. Depletion of neutrophils significantly (p&amp;lt;0.05) reduced infarct size and neurological damage following ischemic stroke in WTmice. However, neutrophil depletion conferred no additional protective effect in KOanimals. Conclusions: These results suggest necrotic platelets interact with neutrophils to exacerbate brain injury following ischemic stroke. As inhibiting platelet necrosis does not compromise hemostasis, targeting platelet CypD may be a potential therapeutic strategy to limit brain damage following ischemic stroke. Disclosures No relevant conflicts of interest to declare.

Antibodies against neural antigens in patients with acute stroke: joint results of three independent cohort studies.

Ischemic stroke (IS) and hemorrhagic stroke (HemS) typically lead to a breakdown of the blood-brain barrier with neural antigen presentation. This presentation could potentially generate destructive auto-immune responses. Pre-existing antineuronal and antiglial antibodies (AA), predominantly NMDA receptor antibodies, have been reported in patients with stroke. This article summarizes three independent prospective studies, the Lübeck cohort (LC), Barcelona cohort (BC), and Heidelberg cohort (HC), exploring the frequency and clinical relevance of AA in patients with acute stroke (AS). In all cohorts together, 344 consecutive patients admitted with AS (322 × IS, 22 × HemS) were screened for AA in serum at admission. Clinical outcome parameters as well as a second AA screening were available at 30days in the LC or at 90days in the BC. A control group was included in the BC (20 subjects free from neurological disease) and the HC (78 neurological and ophthalmological patients without evidence for stroke). The rate of positivity for AA was similar in control subjects and AS patients (13%, 95% CI [7%, 22%] vs. 13%, 95% CI [10%, 17%]; p = 0.46) with no significant difference between cohorts (LC 25/171, BC 12/75, HC 9/98). No patient had developed new AA after 30days, whereas 2 out of 60 patients had developed new AA after 90days. AA positive patients did not exhibit significant differences to AA negative patients in stroke subtype (LC, BC), initial stroke severity (BC, LC, HC), infarct volume (BC), and functional status at admission (BC, LC, HC) and follow-up (BC, LC). AS does not induce AA to a relevant degree. Pre-existing AA can be found in the serum of stroke patients, but they do not have a significant association with clinical features and outcomes.

Detection of Crossed Cerebellar Diaschisis by Intravoxel Incoherent Motion MR Imaging in Subacute Ischemic Stroke

Intravoxel incoherent motion has received extensive attention in brain studies for its potential as a non-invasive magnetic resonance perfusion method. However, studies on intravoxel incoherent motion imaging and crossed cerebellar diaschisis detection are relatively scarce. The aim of our study was to evaluate the feasibility of using intravoxel incoherent motion imaging in crossed cerebellar diaschisis diagnosis in subacute ischemic stroke patients by comparing results from intravoxel incoherent motion imaging, single-photon emission computed tomography, and arterial spin-labeling perfusion methods. In total, 39 patients with subacute ischemic stroke who underwent intravoxel incoherent motion, arterial spin-labeling, and single-photon emission computed tomography scanning were enrolled. Intravoxel incoherent motion-derived perfusion-related parameters including fast diffusion coefficient, vascular volume fraction, arterial spin-labeling-derived cerebral blood flow as well as single-photon emission computed tomography-derived cerebral blood flow of bilateral cerebellum were measured. A crossed cerebellar diaschisis-positive result was considered present with an asymmetry index ≥10% of single-photon emission computed tomography. In the crossed cerebellar diaschisis-positive group, fast diffusion coefficient, arterial spin-labeling-derived cerebral blood flow, and computed tomography-derived cerebral blood flow of the contralateral cerebellum decreased compared with those of the ipsilesional cerebellum; whereas vascular volume fraction significantly increased. The National Institutes of Health Stroke Scale score and infarct volume in the crossed cerebellar diaschisis-positive group were significantly higher than those in the crossed cerebellar diaschisis-negative group. A positive correlation was detected between the fast diffusion coefficient-based asymmetry index and the single-photon emission computed tomography-based asymmetry index, fast diffusion coefficient-based asymmetry, and arterial spin-labeling based asymmetry index; whereas the vascular volume fraction-based asymmetry index value had a negative correlation with the single-photon emission computed tomography-based asymmetry index and arterial spin-labeling based asymmetry index. Furthermore, the area under the receiver operating characteristic curve value of the arterial spin-labeling-based asymmetry index was 0.923. The fast diffusion coefficient derived from the intravoxel incoherent motion could be valuable for the assessment of crossed cerebellar diaschisis in supratentorial stroke patients.

Angioedema in Stroke Patients With Thrombolysis.

Background and Purpose- Oral angioedema (OA) is a rare but life-threatening complication in patients with ischemic stroke receiving intravenous thrombolysis with r-tPA (recombinant tissue-type plasminogen activator). This study intended to determine associations between thrombolysis-related OA and ischemic stroke lesion sites using a voxel-wise lesion analysis. Methods- Prospective registry data were used to identify ischemic stroke patients with thrombolysis-related OA between 2002 and 2018. For the study registry, ethics approval was obtained by the Ethics Committee of the Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg (clinical registry registration: 377_17Bc). Ischemic stroke patients with thrombolysis treatment but without OA admitted in the years 2011 and 2012 comprised the control group. Ischemic lesions were manually outlined on magnetic resonance imaging (1.5T or 3T) or computed tomographic scans and transformed into stereotaxic space. We determined the lesion overlap and compared the absence or presence of OA voxel-wise between patients with and without lesions in a given voxel using the Liebermeister test. Stroke severity was rated using the National Institutes of Health Stroke Scale score, and blood pressure, heart rate, blood glucose levels, and body temperature were determined on admission. Results- Fifteen ischemic stroke patients with thrombolysis-related OA were identified. The voxel-wise analysis yielded associations between OA and ischemic lesions in the insulo-opercular region with a right hemispheric dominance. Mean blood pressure was significantly lower in patients with OA than in controls. Age, National Institutes of Health Stroke Scale scores, infarct volumes, heart rate, and blood glucose levels did not differ between patients with and without OA. Conclusions- The voxel-wise analysis linked thrombolysis-related OA to right insulo-opercular lesions. The lower blood pressure in patients with thrombolysis-related OA may reflect bradykinin effects causing vasodilatation and increasing vascular permeability.

Potential Neuroprotective Effect of miR-451 Against Cerebral Ischemia/Reperfusion Injury in Stroke Patients and a Mouse Model

Recently, microRNAs (miRs) have been reported to be novel regulators in ischemic stroke. In this study, we investigated the pattern of miR-451 expression along with its clinical application in human ischemic stroke and in an invivo mouse model. The level of miR-451 was evaluated in patients and mice after ischemic stroke. National Institute of Health Stroke Scale scores and brain infarct volume were analyzed to the correlation of miR-451 expression and clinical information. In addition, blood samples and brain tissues were collected from an established middle cerebral artery occlusion model consisting of 12 adult male mice at 24 hours after the middle cerebral artery occlusion. The results showed that miR-451 levels in the circulating blood of ischemic stroke patients were greatly decreased compared with the control. Further correlation analysis revealed a negative association between miR-451and National Institute of Health Stroke Scalescores (r= -0.6104, P < 0.001) and infarct volume (r= -0.5442, P < 0.001). Moreover, miR-451 was down-regulated in response to middle cerebral artery occlusion invivo, along with a negative correlation between miR-451 in brain and blood (r= 0.9240, P < 0.01). In addition, forced expression of miR-451 weakened ischemic brain infarction and apoptosis levels in focal ischemia-stroked mice, whiledownregulation of miR-451 significantly augmented ischemic injury. In conclusion, miR-451 displays the neuroprotective effect in ischemic stroke and might serve as a novel therapeutic target of ischemic stroke.

Predicting ischemic stroke tissue fate using a deep convolutional neural network on source magnetic resonance perfusion images.

Predicting infarct volume from magnetic resonance perfusion-weighted imaging can provide helpful information to clinicians in deciding how aggressively to treat acute stroke patients. Models have been developed to predict tissue fate, yet these models are mostly built using hand-crafted features (e.g., time-to-maximum) derived from perfusion images, which are sensitive to deconvolution methods. We demonstrate the application of deep convolution neural networks (CNNs) on predicting final stroke infarct volume using only the source perfusion images. We propose a deep CNN architecture that improves feature learning and achieves an area under the curve of , outperforming existing tissue fate models. We further validate the proposed deep CNN with existing 2-D and 3-D deep CNNs for images/video classification, showing the importance of the proposed architecture. Our work leverages deep learning techniques in stroke tissue outcome prediction, advancing magnetic resonance imaging perfusion analysis one step closer to an operational decision support tool for stroke treatment guidance.

Cytokine‐stimulated iNOS Expression Requires Long Chain Fatty Acyl CoA Synthetase (ACSL)

RationaleACSL catalyzes the ligation of fatty acid to coenzyme A, the first and rate limiting step for fatty acid utilization. Triacsin C is a fungal metabolite which inhibits ACSL1, ACSL3, and ACSL4. Earlier, we showed that Triacsin C reduces the infarct volume and inhibits iNOS expression in the MCAO model of stroke. As iNOS is up‐regulated in stroke, we wished to determine whether the Triacsin C effect was linked to iNOS expression.MethodsbEnd.3 cells were stimulated with cytokine mix, (TNFα, 60 ng/mL; Ilβ,2 ng/mL; IFNγ, 100 units/mL), in the presence or absence of 5μM Triacsin C for 24 hours. RNA was extracted following RNeasy Plus Mini Kit(Qiagaen) instruction. The concentration and purity of RNA was determined by Spectrophometer. 20 μl first strand cDNA was synthesized from 1 μg total RNA for each sample using Superscript III First‐Strand(Invitrogen). One μl cDNA was amplified using SYBR Green PCR Master Mix (applied Biosystems) in CFX96 Touch Real‐Time PCR Detection System (BioRad). β‐actin (cat 330001 PPM02945B) and iNOS (cat 330001PPM02928B) primers were purchased from Qiagen. Expression level in fold change was determined by the comparative threshold cycle method (2−ΔΔCt) with β‐actin as the control gene.ResultsCytomix stimulated iNOS expression in the presence of Triacsin C was 52.8 ± 8.33% of control. (p=0.0005; n=5 independent experiments).ConclusionsOur data confirm that iNOS expression is modulated by ACSL activity, and support our hypothesis that the Triacsin C effect on stroke infarct volume is related to suppression of iNOS expression.Support or Funding InformationDepartment of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TXThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.