TY - JOUR A1 - Bieber, Michael A1 - Schuhmann, Michael K. A1 - Bellut, Maximilian A1 - Stegner, David A1 - Heinze, Katrin G. A1 - Pham, Mirko A1 - Nieswandt, Bernhard A1 - Stoll, Guido T1 - Blockade of platelet glycoprotein Ibα augments neuroprotection in Orai2-deficient mice during middle cerebral artery occlusion JF - International Journal of Molecular Sciences N2 - During ischemic stroke, infarct growth before recanalization diminishes functional outcome. Hence, adjunct treatment options to protect the ischemic penumbra before recanalization are eagerly awaited. In experimental stroke targeting two different pathways conferred protection from penumbral tissue loss: (1) enhancement of hypoxic tolerance of neurons by deletion of the calcium channel subunit Orai2 and (2) blocking of detrimental lymphocyte–platelet responses. However, until now, no preclinical stroke study has assessed the potential of combining neuroprotective with anti-thrombo-inflammatory interventions to augment therapeutic effects. We induced focal cerebral ischemia in Orai2-deficient (Orai2\(^{-/-}\)) mice by middle cerebral artery occlusion (MCAO). Animals were treated with anti-glycoprotein Ib alpha (GPIbα) Fab fragments (p0p/B Fab) blocking GPIbα–von Willebrand factor (vWF) interactions. Rat immunoglobulin G (IgG) Fab was used as the control treatment. The extent of infarct growth before recanalization was assessed at 4 h after MCAO. Moreover, infarct volumes were determined 6 h after recanalization (occlusion time: 4 h). Orai2 deficiency significantly halted cerebral infarct progression under occlusion. Inhibition of platelet GPIbα further reduced primary infarct growth in Orai2\(^{-/-}\) mice. During ischemia–reperfusion, upon recanalization, mice were likewise protected. All in all, we show that neuroprotection in Orai2\(^{-/-}\) mice can be augmented by targeting thrombo-inflammation. This supports the clinical development of combined neuroprotective/anti-platelet strategies in hyper-acute stroke. KW - ischemic penumbra KW - Orai2 KW - glycoprotein receptor Ibα KW - ischemic stroke KW - thrombo-inflammation KW - middle cerebral artery occlusion Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286038 SN - 1422-0067 VL - 23 IS - 16 ER - TY - JOUR A1 - Schanbacher, Constanze A1 - Bieber, Michael A1 - Reinders, Yvonne A1 - Cherpokova, Deya A1 - Teichert, Christina A1 - Nieswandt, Bernhard A1 - Sickmann, Albert A1 - Kleinschnitz, Christoph A1 - Langhauser, Friederike A1 - Lorenz, Kristina T1 - ERK1/2 activity is critical for the outcome of ischemic stroke JF - International Journal of Molecular Sciences N2 - Ischemic disorders are the leading cause of death worldwide. The extracellular signal-regulated kinases 1 and 2 (ERK1/2) are thought to affect the outcome of ischemic stroke. However, it is under debate whether activation or inhibition of ERK1/2 is beneficial. In this study, we report that the ubiquitous overexpression of wild-type ERK2 in mice (ERK2\(^{wt}\)) is detrimental after transient occlusion of the middle cerebral artery (tMCAO), as it led to a massive increase in infarct volume and neurological deficits by increasing blood–brain barrier (BBB) leakiness, inflammation, and the number of apoptotic neurons. To compare ERK1/2 activation and inhibition side-by-side, we also used mice with ubiquitous overexpression of the Raf-kinase inhibitor protein (RKIP\(^{wt}\)) and its phosphorylation-deficient mutant RKIP\(^{S153A}\), known inhibitors of the ERK1/2 signaling cascade. RKIP\(^{wt}\) and RKIP\(^{S153A}\) attenuated ischemia-induced damages, in particular via anti-inflammatory signaling. Taken together, our data suggest that stimulation of the Raf/MEK/ERK1/2-cascade is severely detrimental and its inhibition is rather protective. Thus, a tight control of the ERK1/2 signaling is essential for the outcome in response to ischemic stroke. KW - ERK1/2 KW - tMCAO KW - ischemic stroke KW - RKIP Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-283991 SN - 1422-0067 VL - 23 IS - 2 ER - TY - JOUR A1 - Strinitz, Marc A1 - Pham, Mirko A1 - März, Alexander G. A1 - Feick, Jörn A1 - Weidner, Franziska A1 - Vogt, Marius L. A1 - Essig, Fabian A1 - Neugebauer, Hermann A1 - Stoll, Guido A1 - Schuhmann, Michael K. A1 - Kollikowski, Alexander M. T1 - Immune cells invade the collateral circulation during human stroke: prospective replication and extension JF - International Journal of Molecular Sciences N2 - It remains unclear if principal components of the local cerebral stroke immune response can be reliably and reproducibly observed in patients with acute large-vessel-occlusion (LVO) stroke. We prospectively studied a large independent cohort of n = 318 consecutive LVO stroke patients undergoing mechanical thrombectomy during which cerebral blood samples from within the occluded anterior circulation and systemic control samples from the ipsilateral cervical internal carotid artery were obtained. An extensive protocol was applied to homogenize the patient cohort and to standardize the procedural steps of endovascular sample collection, sample processing, and laboratory analyses. N = 58 patients met all inclusion criteria. (1) Mean total leukocyte counts were significantly higher within the occluded ischemic cerebral vasculature (I) vs. intraindividual systemic controls (S): +9.6%, I: 8114/µL ± 529 vs. S: 7406/µL ± 468, p = 0.0125. (2) This increase was driven by neutrophils: +12.1%, I: 7197/µL ± 510 vs. S: 6420/µL ± 438, p = 0.0022. Leukocyte influx was associated with (3) reduced retrograde collateral flow (R\(^2\) = 0.09696, p = 0.0373) and (4) greater infarct extent (R\(^2\) = 0.08382, p = 0.032). Despite LVO, leukocytes invade the occluded territory via retrograde collateral pathways early during ischemia, likely compromising cerebral hemodynamics and tissue integrity. This inflammatory response can be reliably observed in human stroke by harvesting immune cells from the occluded cerebral vascular compartment. KW - ischemic stroke KW - cerebral ischemia KW - mechanical thrombectomy KW - large vessel occlusion KW - leukocytes KW - neutrophils KW - collateral circulation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284281 SN - 1422-0067 VL - 22 IS - 17 ER - TY - JOUR A1 - Mammadova-Bach, Elmina A1 - Braun, Attila T1 - Zinc homeostasis in platelet-related diseases JF - International Journal of Molecular Sciences N2 - Zn\(^{2+}\) deficiency in the human population is frequent in underdeveloped countries. Worldwide, approximatively 2 billion people consume Zn\(^{2+}\)-deficient diets, accounting for 1–4% of deaths each year, mainly in infants with a compromised immune system. Depending on the severity of Zn\(^{2+}\) deficiency, clinical symptoms are associated with impaired wound healing, alopecia, diarrhea, poor growth, dysfunction of the immune and nervous system with congenital abnormalities and bleeding disorders. Poor nutritional Zn\(^{2+}\) status in patients with metastatic squamous cell carcinoma or with advanced non-Hodgkin lymphoma, was accompanied by cutaneous bleeding and platelet dysfunction. Forcing Zn\(^{2+}\) uptake in the gut using different nutritional supplementation of Zn\(^{2+}\) could ameliorate many of these pathological symptoms in humans. Feeding adult rodents with a low Zn\(^{2+}\) diet caused poor platelet aggregation and increased bleeding tendency, thereby attracting great scientific interest in investigating the role of Zn\(^{2+}\) in hemostasis. Storage protein metallothionein maintains or releases Zn\(^{2+}\) in the cytoplasm, and the dynamic change of this cytoplasmic Zn\(^{2+}\) pool is regulated by the redox status of the cell. An increase of labile Zn\(^{2+}\) pool can be toxic for the cells, and therefore cytoplasmic Zn\(^{2+}\) levels are tightly regulated by several Zn\(^{2+}\) transporters located on the cell surface and also on the intracellular membrane of Zn\(^{2+}\) storage organelles, such as secretory vesicles, endoplasmic reticulum or Golgi apparatus. Although Zn\(^{2+}\) is a critical cofactor for more than 2000 transcription factors and 300 enzymes, regulating cell differentiation, proliferation, and basic metabolic functions of the cells, the molecular mechanisms of Zn\(^{2+}\) transport and the physiological role of Zn\(^{2+}\) store in megakaryocyte and platelet function remain elusive. In this review, we summarize the contribution of extracellular or intracellular Zn\(^{2+}\) to megakaryocyte and platelet function and discuss the consequences of dysregulated Zn\(^{2+}\) homeostasis in platelet-related diseases by focusing on thrombosis, ischemic stroke and storage pool diseases. KW - Zinc KW - platelets KW - hemostasis KW - thrombosis KW - ischemic stroke KW - storage-pool diseases Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285554 SN - 1422-0067 VL - 20 IS - 21 ER - TY - JOUR A1 - Strilciuc, Stefan A1 - Vécsei, László A1 - Boering, Dana A1 - Pražnikar, Aleš A1 - Kaut, Oliver A1 - Riederer, Peter A1 - Battistin, Leontino T1 - Safety of Cerebrolysin for neurorecovery after acute ischemic stroke: a systematic review and meta-analysis of twelve randomized-controlled trials JF - Pharmaceuticals N2 - We performed a systematic search and meta-analysis of available literature to determine the safety profile of Cerebrolysin in acute ischemic stroke, filling existing safety information gaps and inconsistent results. We searched EMBASE, PubMed, and Cochrane Databases of Systematic Reviews and Clinical Trials up to the end of February 2021. Data collection and analysis were conducted using methods described in the Cochrane Handbook for Systematic Reviews of Interventions. All safety outcomes were analyzed based on risk ratios (RR) and their 95% confidence intervals. The meta-analysis pooled 2202 patients from twelve randomized clinical trials, registering non-statistically significant (p > 0.05) differences between Cerebrolysin and placebo throughout main and subgroup analyses. The lowest rate of Serious Adverse Events (SAE), as compared to placebo, was observed for the highest dose of Cerebrolysin (50 mL), highlighting a moderate reduction (RR = 0.6). We observed a tendency of superiority of Cerebrolysin regarding SAE in high dose treatment courses for moderate-severe ischemic stroke, suggesting some effect of the agent against adverse events. This comprehensive safety meta-analysis confirms the safety profile for patients treated with Cerebrolysin after acute ischemic stroke, as compared to placebo. KW - ischemic stroke KW - safety KW - Cerebrolysin KW - neurorehabilitation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252403 SN - 1424-8247 VL - 14 IS - 12 ER - TY - JOUR A1 - Bellut, Maximilian A1 - Raimondi, Anthony T. A1 - Haarmann, Axel A1 - Zimmermann, Lena A1 - Stoll, Guido A1 - Schuhmann, Michael K. T1 - NLRP3 inhibition reduces rt-PA induced endothelial dysfunction under ischemic conditions JF - Biomedicines N2 - Thrombolysis with recombinant tissue plasminogen activator (rt-PA) is a mainstay of acute ischemic stroke treatment but is associated with bleeding complications, especially after prolonged large vessel occlusion. Recently, inhibition of the NLRP3 inflammasome led to preserved blood–brain barrier (BBB) integrity in experimental stroke in vivo. To further address the potential of NLRP3 inflammasome inhibition as adjunct stroke treatment we used immortalized brain derived endothelial cells (bEnd5) as an in vitro model of the BBB. We treated bEnd5 with rt-PA in combination with the NLRP3 specific inhibitor MCC950 or vehicle under normoxic as well as ischemic (OGD) conditions. We found that rt-PA exerted a cytotoxic effect on bEnd5 cells under OGD confirming that rt-PA is harmful to the BBB. This detrimental effect could be significantly reduced by MCC950 treatment. Moreover, under ischemic conditions, the Cell Index — a sensible indicator for a patent BBB — and the protein expression of Zonula occludens 1 stabilized after MCC950 treatment. At the same time, the extent of endothelial cell death and NLRP3 expression decreased. In conclusion, NLRP3 inhibition can protect the BBB from rt-PA-induced damage and thereby potentially increase the narrow time window for safe thrombolysis in stroke. KW - NLRP3 KW - inflammasome KW - MCC950 KW - rt-PA KW - blood–brain barrier KW - Cell Index KW - ASC KW - ischemic stroke KW - i.v. thrombolysis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267261 SN - 2227-9059 VL - 10 IS - 4 ER - TY - JOUR A1 - Montellano, Felipe A. A1 - Kluter, Elisabeth J. A1 - Rücker, Viktoria A1 - Ungethüm, Kathrin A1 - Mackenrodt, Daniel A1 - Wiedmann, Silke A1 - Dege, Tassilo A1 - Quilitzsch, Anika A1 - Morbach, Caroline A1 - Frantz, Stefan A1 - Störk, Stefan A1 - Haeusler, Karl Georg A1 - Kleinschnitz, Christoph A1 - Heuschmann, Peter U. T1 - Cardiac dysfunction and high-sensitive C-reactive protein are associated with troponin T elevation in ischemic stroke: insights from the SICFAIL study JF - BMC Neurology N2 - Background Troponin elevation is common in ischemic stroke (IS) patients. The pathomechanisms involved are incompletely understood and comprise coronary and non-coronary causes, e.g. autonomic dysfunction. We investigated determinants of troponin elevation in acute IS patients including markers of autonomic dysfunction, assessed by heart rate variability (HRV) time domain variables. Methods Data were collected within the Stroke Induced Cardiac FAILure (SICFAIL) cohort study. IS patients admitted to the Department of Neurology, Würzburg University Hospital, underwent baseline investigation including cardiac history, physical examination, echocardiography, and blood sampling. Four HRV time domain variables were calculated in patients undergoing electrocardiographic Holter monitoring. Multivariable logistic regression with corresponding odds ratios (OR) and 95% confidence intervals (CI) was used to investigate the determinants of high-sensitive troponin T (hs-TnT) levels ≥14 ng/L. Results We report results from 543 IS patients recruited between 01/2014–02/2017. Of those, 203 (37%) had hs-TnT ≥14 ng/L, which was independently associated with older age (OR per year 1.05; 95% CI 1.02–1.08), male sex (OR 2.65; 95% CI 1.54–4.58), decreasing estimated glomerular filtration rate (OR per 10 mL/min/1.73 m2 0.71; 95% CI 0.61–0.84), systolic dysfunction (OR 2.79; 95% CI 1.22–6.37), diastolic dysfunction (OR 2.29; 95% CI 1.29–4.02), atrial fibrillation (OR 2.30; 95% CI 1.25–4.23), and increasing levels of C-reactive protein (OR 1.48 per log unit; 95% CI 1.22–1.79). We did not identify an independent association of troponin elevation with the investigated HRV variables. Conclusion Cardiac dysfunction and elevated C-reactive protein, but not a reduced HRV as surrogate of autonomic dysfunction, were associated with increased hs-TnT levels in IS patients independent of established cardiovascular risk factors. KW - echocardiography KW - ischemic stroke KW - troponin KW - heart failure KW - biomarkers Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300119 VL - 22 IS - 1 ER - TY - JOUR A1 - Bellut, Maximilian A1 - Bieber, Michael A1 - Kraft, Peter A1 - Weber, Alexander N. R. A1 - Stoll, Guido A1 - Schuhmann, Michael K. T1 - Delayed NLRP3 inflammasome inhibition ameliorates subacute stroke progression in mice JF - Journal of Neuroinflammation N2 - Background Ischemic stroke immediately evokes a strong neuro-inflammatory response within the vascular compartment, which contributes to primary infarct development under vessel occlusion as well as further infarct growth despite recanalization, referred to as ischemia/reperfusion injury. Later, in the subacute phase of stroke (beyond day 1 after recanalization), further inflammatory processes within the brain parenchyma follow. Whether this second wave of parenchymal inflammation contributes to an additional/secondary increase in infarct volumes and bears the potential to be pharmacologically targeted remains elusive. We addressed the role of the NLR-family pyrin domain-containing protein 3 (NLRP3) inflammasome in the subacute phase of ischemic stroke. Methods Focal cerebral ischemia was induced in C57Bl/6 mice by a 30-min transient middle cerebral artery occlusion (tMCAO). Animals were treated with the NLRP3 inhibitor MCC950 therapeutically 24 h after or prophylactically before tMCAO. Stroke outcome, including infarct size and functional deficits as well as the local inflammatory response, was assessed on day 7 after tMCAO. Results Infarct sizes on day 7 after tMCAO decreased about 35% after delayed and about 60% after prophylactic NLRP3 inhibition compared to vehicle. Functionally, pharmacological inhibition of NLRP3 mitigated the local inflammatory response in the ischemic brain as indicated by reduction of infiltrating immune cells and reactive astrogliosis. Conclusions Our results demonstrate that the NLRP3 inflammasome continues to drive neuroinflammation within the subacute stroke phase. NLRP3 inflammasome inhibition leads to a better long-term outcome—even when administered with a delay of 1 day after stroke induction, indicating ongoing inflammation-driven infarct progression. These findings may pave the way for eagerly awaited delayed treatment options in ischemic stroke. KW - ischemic stroke KW - secondary infarct growth KW - neuroinflammation KW - middle cerebral artery occlusion KW - NLRP3 KW - inflammasome Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300599 VL - 20 IS - 1 ER - TY - JOUR A1 - Kollikowski, Alexander M. A1 - Pham, Mirko A1 - März, Alexander G. A1 - Papp, Lena A1 - Nieswandt, Bernhard A1 - Stoll, Guido A1 - Schuhmann, Michael K. T1 - Platelet Activation and Chemokine Release Are Related to Local Neutrophil-Dominant Inflammation During Hyperacute Human Stroke JF - Translational Stroke Research N2 - Experimental evidence has emerged that local platelet activation contributes to inflammation and infarct formation in acute ischemic stroke (AIS) which awaits confirmation in human studies. We conducted a prospective observational study on 258 consecutive patients undergoing mechanical thrombectomy (MT) due to large-vessel-occlusion stroke of the anterior circulation (08/2018-05/2020). Intraprocedural microcatheter aspiration of 1 ml of local (occlusion condition) and systemic arterial blood samples (self-control) was performed according to a prespecified protocol. The samples were analyzed for differential leukocyte counts, platelet counts, and plasma levels of the platelet-derived neutrophil-activating chemokine C-X-C-motif ligand (CXCL) 4 (PF-4), the neutrophil attractant CXCL7 (NAP-2), and myeloperoxidase (MPO). The clinical-biological relevance of these variables was corroborated by specific associations with molecular-cellular, structural-radiological, hemodynamic, and clinical-functional parameters. Seventy consecutive patients fulfilling all predefined criteria entered analysis. Mean local CXCL4 (+ 39%: 571 vs 410 ng/ml, P = .0095) and CXCL7 (+ 9%: 693 vs 636 ng/ml, P = .013) concentrations were higher compared with self-controls. Local platelet counts were lower (- 10%: 347,582 vs 383,284/µl, P = .0052), whereas neutrophil counts were elevated (+ 10%: 6022 vs 5485/µl, P = 0.0027). Correlation analyses revealed associations between local platelet and neutrophil counts (r = 0.27, P = .034), and between CXCL7 and MPO (r = 0.24, P = .048). Local CXCL4 was associated with the angiographic degree of reperfusion following recanalization (r =  - 0.2523, P = .0479). Functional outcome at discharge correlated with local MPO concentrations (r = 0.3832, P = .0014) and platelet counts (r = 0.288, P = .0181). This study provides human evidence of cerebral platelet activation and platelet-neutrophil interactions during AIS and points to the relevance of per-ischemic thrombo-inflammatory mechanisms to impaired reperfusion and worse functional outcome following recanalization. KW - chemokines KW - CXCL4 KW - PF4 KW - CXCL7 KW - NAP-2 KW - ischemic stroke Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270194 SN - 1868-601X VL - 13 IS - 3 ER - TY - JOUR A1 - Tütüncü, Serdar A1 - Olma, Manuel A1 - Kunze, Claudia A1 - Dietzel, Joanna A1 - Schurig, Johannes A1 - Fiessler, Cornelia A1 - Malsch, Carolin A1 - Haas, Tobias Eberhard A1 - Dimitrijeski, Boris A1 - Doehner, Wolfram A1 - Hagemann, Georg A1 - Hamilton, Frank A1 - Honermann, Martin A1 - Jungehulsing, Gerhard Jan A1 - Kauert, Andreas A1 - Koennecke, Hans-Christian A1 - Mackert, Bruno-Marcel A1 - Nabavi, Darius A1 - Nolte, Christian H. A1 - Reis, Joschua Mirko A1 - Schmehl, Ingo A1 - Sparenberg, Paul A1 - Stingele, Robert A1 - Völzke, Enrico A1 - Waldschmidt, Carolin A1 - Zeise-Wehry, Daniel A1 - Heuschmann, Peter U. A1 - Endress, Matthias A1 - Haeusler, Karl Georg T1 - Off-label-dosing of non-vitamin K-dependent oral antagonists in AF patients before and after stroke: results of the prospective multicenter Berlin Atrial Fibrillation Registry JF - Journal of Neurology N2 - Aims We aimed to analyze prevalence and predictors of NOAC off-label under-dosing in AF patients before and after the index stroke. Methods The post hoc analysis included 1080 patients of the investigator-initiated, multicenter prospective Berlin Atrial Fibrillation Registry, designed to analyze medical stroke prevention in AF patients after acute ischemic stroke. Results At stroke onset, an off-label daily dose was prescribed in 61 (25.5%) of 239 NOAC patients with known AF and CHA2DS2-VASc score ≥ 1, of which 52 (21.8%) patients were under-dosed. Under-dosing was associated with age ≥ 80 years in patients on rivaroxaban [OR 2.90, 95% CI 1.05-7.9, P = 0.04; n = 29] or apixaban [OR 3.24, 95% CI 1.04-10.1, P = 0.04; n = 22]. At hospital discharge after the index stroke, NOAC off-label dose on admission was continued in 30 (49.2%) of 61 patients. Overall, 79 (13.7%) of 708 patients prescribed a NOAC at hospital discharge received an off-label dose, of whom 75 (10.6%) patients were under-dosed. Rivaroxaban under-dosing at discharge was associated with age ≥ 80 years [OR 3.49, 95% CI 1.24-9.84, P = 0.02; n = 19]; apixaban under-dosing with body weight ≤ 60 kg [OR 0.06, 95% CI 0.01-0.47, P < 0.01; n = 56], CHA2DS2-VASc score [OR per point 1.47, 95% CI 1.08-2.00, P = 0.01], and HAS-BLED score [OR per point 1.91, 95% CI 1.28-2.84, P < 0.01]. Conclusion At stroke onset, off-label dosing was present in one out of four, and under-dosing in one out of five NOAC patients. Under-dosing of rivaroxaban or apixaban was related to old age. In-hospital treatment after stroke reduced off-label NOAC dosing, but one out of ten NOAC patients was under-dosed at discharge. KW - NOAC KW - ischemic stroke KW - atrial fibrillation KW - under-dosing Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266969 SN - 1432-1459 VL - 269 IS - 1 ER -