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 - Bellut, Maximilian A1 - Papp, Lena A1 - Bieber, Michael A1 - Kraft, Peter A1 - Stoll, Guido A1 - Schuhmann, Michael K. T1 - NLPR3 inflammasome inhibition alleviates hypoxic endothelial cell death in-vitro and protects blood-brain barrier integrity in murine stroke JF - Cell Death & Disease N2 - In ischemic stroke (IS) impairment of the blood-brain barrier (BBB) has an important role in the secondary deterioration of neurological function. BBB disruption is associated with ischemia-induced inflammation, brain edema formation, and hemorrhagic infarct transformation, but the underlying mechanisms are incompletely understood. Dysfunction of endothelial cells (EC) may play a central role in this process. Although neuronal NLR-family pyrin domain-containing protein 3 (NLRP3) inflammasome upregulation is an established trigger of inflammation in IS, the contribution of its expression in EC is unclear. We here used brain EC, exposed them to oxygen and glucose deprivation (OGD) in vitro, and analyzed their survival depending on inflammasome inhibition with the NLRP3-specific drug MCC950. During OGD, EC death could significantly be reduced when targeting NLRP3, concomitant with diminished endothelial NLRP3 expression. Furthermore, MCC950 led to reduced levels of Caspase 1 (p20) and activated Gasdermin D as markers for pyroptosis. Moreover, inflammasome inhibition reduced the secretion of pro-inflammatory chemokines, cytokines, and matrix metalloproteinase-9 (MMP9) in EC. In a translational approach, IS was induced in C57Bl/6 mice by 60 mins transient middle cerebral artery occlusion and 23 hours of reperfusion. Stroke volume, functional outcome, the BBB integrity, and-in good agreement with the in vitro results-MMP9 secretion as well as EC survival improved significantly in MCC950-treated mice. In conclusion, our results establish the NLRP3 inflammasome as a critical pathogenic effector of stroke-induced BBB disruption by activating inflammatory signaling cascades and pyroptosis in brain EC. KW - inflammasome KW - preclinical research KW - stroke Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265693 VL - 13 ER - TY - JOUR A1 - Bieber, Michael A1 - Foerster, Kathrin I. A1 - Haefeli, Walter E. A1 - Pham, Mirko A1 - Schuhmann, Michael K. A1 - Kraft, Peter T1 - Treatment with edoxaban attenuates acute stroke severity in mice by reducing blood–brain barrier damage and inflammation JF - International Journal of Molecular Sciences N2 - Patients with atrial fibrillation and previous ischemic stroke (IS) are at increased risk of cerebrovascular events despite anticoagulation. In these patients, treatment with non-vitamin K oral anticoagulants (NOAC) such as edoxaban reduced the probability and severity of further IS without increasing the risk of major bleeding. However, the detailed protective mechanism of edoxaban has not yet been investigated in a model of ischemia/reperfusion injury. Therefore, in the current study we aimed to assess in a clinically relevant setting whether treatment with edoxaban attenuates stroke severity, and whether edoxaban has an impact on the local cerebral inflammatory response and blood–brain barrier (BBB) function after experimental IS in mice. Focal cerebral ischemia was induced by transient middle cerebral artery occlusion in male mice receiving edoxaban, phenprocoumon or vehicle. Infarct volumes, functional outcome and the occurrence of intracerebral hemorrhage were assessed. BBB damage and the extent of local inflammatory response were determined. Treatment with edoxaban significantly reduced infarct volumes and improved neurological outcome and BBB function on day 1 and attenuated brain tissue inflammation. In summary, our study provides evidence that edoxaban might exert its protective effect in human IS by modulating different key steps of IS pathophysiology, but further studies are warranted. KW - edoxaban KW - thrombo-inflammation KW - blood–brain barrier KW - tMCAO KW - experimental stroke KW - hemorrhagic transformation KW - NOAC Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284481 SN - 1422-0067 VL - 22 IS - 18 ER - TY - JOUR A1 - Essig, Fabian A1 - Babilon, Lilith A1 - Vollmuth, Christoph A1 - Kollikowski, Alexander M. A1 - Pham, Mirko A1 - Solymosi, László A1 - Haeusler, Karl Georg A1 - Kraft, Peter A1 - Stoll, Guido A1 - Schuhmann, Michael K. T1 - High mobility group box 1 protein in cerebral thromboemboli JF - International Journal of Molecular Sciences N2 - High-mobility group box 1 protein (HMGB1) is a damage-associated molecular pattern (DAMP) involved in neutrophil extracellular trap (NET) formation and thrombosis. NETs are regularly found in cerebral thromboemboli. We here analyzed associated HMGB1 expression in human thromboemboli retrieved via mechanical thrombectomy from 37 stroke patients with large vessel occlusion. HMGB1 was detected in all thromboemboli, accounting for 1.7% (IQR 0.6–6.2%) of the total thromboemboli area and was found to be colocalized with neutrophils and NETs and in spatial proximity to platelets. Correlation analysis revealed that the detection of HMGB1 was strongly related to the number of neutrophils (r = 0.58, p = 0.0002) and platelets (r = 0.51, p = 0.001). Our results demonstrate that HMGB1 is a substantial constituent of thromboemboli causing large vessel occlusion stroke. KW - acute ischemic stroke KW - thromboemboli KW - HMGB1 KW - neutrophils KW - platelets KW - immunohistochemistry Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265568 SN - 1422-0067 VL - 22 IS - 20 ER - TY - JOUR A1 - Essig, Fabian A1 - Kollikowski, Alexander M. A1 - Pham, Mirko A1 - Solymosi, László A1 - Stoll, Guido A1 - Haeusler, Karl Georg A1 - Kraft, Peter A1 - Schuhmann, Michael K. T1 - Immunohistological analysis of neutrophils and neutrophil extracellular traps in human thrombemboli causing acute ischemic stroke JF - International Journal of Molecular Sciences N2 - Ischemic stroke caused by thromboembolic occlusion of large cerebral arteries, such as the internal carotid (ICA) and/or the middle cerebral artery (MCA), is treated by mechanical thrombectomy (MT). MT allows salvage of the vessel-occluding thrombemboli, which most frequently originate from the left atrium or the left ventricle of the heart or from sites of plaque rupture within large arteries above the heart. Clot composition may influence the efficacy of (intravenous) thrombolysis and MT, respectively. We analyzed 37 human thrombemboli obtained from acute ischemic stroke patients during MT with special emphasis on histological staining of neutrophils and neutrophil extracellular traps (NETs). We found neutrophils as the main cellular component of cerebral thrombemboli but encountered considerable morphological heterogeneity. Neutrophils accumulated in the border region of fibrin-rich structures indicating possible interaction of neutrophils with distinct structural thrombembolus components. Web-like NETs were found in 35 of 37 thrombemboli in varying amounts. NETs were almost exclusively found within fibrin-rich areas. Importantly, stroke etiology, age and present oral anticoagulation was associated with morphological patterns and the amount of neutrophils. Correlation of histological data and imaging data revealed that relative Hounsfield units of cerebral thrombemboli positively correlated with the amount of red blood cells. In summary, our results demonstrate that neutrophils and NETs are substantial constituents of cerebral thrombemboli and contribute to their structural complexity. KW - acute ischemic stroke KW - thrombemboli KW - neutrophils KW - NETs KW - immunohistochemistry Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236192 SN - 1422-0067 VL - 21 IS - 19 ER - TY - JOUR A1 - Gabriel, Katharina M. A. A1 - Jírů-Hillmann, Steffi A1 - Kraft, Peter A1 - Selig, Udo A1 - Rücker, Victoria A1 - Mühler, Johannes A1 - Dötter, Klaus A1 - Keidel, Matthias A1 - Soda, Hassan A1 - Rascher, Alexandra A1 - Schneider, Rolf A1 - Pfau, Mathias A1 - Hoffmann, Roy A1 - Stenzel, Joachim A1 - Benghebrid, Mohamed A1 - Goebel, Tobias A1 - Doerck, Sebastian A1 - Kramer, Daniela A1 - Haeusler, Karl Georg A1 - Volkmann, Jens A1 - Heuschmann, Peter U. A1 - Fluri, Felix T1 - Two years' experience of implementing a comprehensive telemedical stroke network comprising in mainly rural region: the Transregional Network for Stroke Intervention with Telemedicine (TRANSIT-Stroke) JF - BMC Neurology N2 - Background Telemedicine improves the quality of acute stroke care in rural regions with limited access to specialized stroke care. We report the first 2 years' experience of implementing a comprehensive telemedical stroke network comprising all levels of stroke care in a defined region. Methods The TRANSIT-Stroke network covers a mainly rural region in north-western Bavaria (Germany). All hospitals providing acute stroke care in this region participate in TRANSIT-Stroke, including four hospitals with a supra-regional certified stroke unit (SU) care (level III), three of those providing teleconsultation to two hospitals with a regional certified SU (level II) and five hospitals without specialized SU care (level I). For a two-year-period (01/2015 to 12/2016), data of eight of these hospitals were available; 13 evidence-based quality indicators (QIs) related to processes during hospitalisation were evaluated quarterly and compared according to predefined target values between level-I- and level-II/III-hospitals. Results Overall, 7881 patients were included (mean age 74.6 years +/- 12.8; 48.4% female). In level-II/III-hospitals adherence of all QIs to predefined targets was high ab initio. In level-I-hospitals, three patterns of QI-development were observed: a) high adherence ab initio (31%), mainly in secondary stroke prevention; b) improvement over time (44%), predominantly related to stroke specific diagnosis and in-hospital organization; c) no clear time trends (25%). Overall, 10 out of 13 QIs reached predefined target values of quality of care at the end of the observation period. Conclusion The implementation of the comprehensive TRANSIT-Stroke network resulted in an improvement of quality of care in level-I-hospitals. KW - pilot project KW - care tempis KW - ischemic stroke KW - thrombolysis KW - areas KW - time KW - hospitals KW - mortality KW - outcomes KW - quality Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229214 VL - 20 ER - TY - JOUR A1 - Göbel, Kerstin A1 - Pankratz, Susann A1 - Asaridou, Chloi-Magdalini A1 - Herrmann, Alexander M. A1 - Bittner, Stefan A1 - Merker, Monika A1 - Ruck, Tobias A1 - Glumm, Sarah A1 - Langhauser, Friederike A1 - Kraft, Peter A1 - Krug, Thorsten F. A1 - Breuer, Johanna A1 - Herold, Martin A1 - Gross, Catharina C. A1 - Beckmann, Denise A1 - Korb-Pap, Adelheid A1 - Schuhmann, Michael K. A1 - Kuerten, Stefanie A1 - Mitroulis, Ioannis A1 - Ruppert, Clemens A1 - Nolte, Marc W. A1 - Panousis, Con A1 - Klotz, Luisa A1 - Kehrel, Beate A1 - Korn, Thomas A1 - Langer, Harald F. A1 - Pap, Thomas A1 - Nieswandt, Bernhard A1 - Wiendl, Heinz A1 - Chavakis, Triantafyllos A1 - Kleinschnitz, Christoph A1 - Meuth, Sven G. T1 - Blood coagulation factor XII drives adaptive immunity during neuroinflammation via CD87-mediated modulation of dendritic cells JF - Nature Communications N2 - Aberrant immune responses represent the underlying cause of central nervous system (CNS) autoimmunity, including multiple sclerosis (MS). Recent evidence implicated the crosstalk between coagulation and immunity in CNS autoimmunity. Here we identify coagulation factor XII (FXII), the initiator of the intrinsic coagulation cascade and the kallikrein–kinin system, as a specific immune cell modulator. High levels of FXII activity are present in the plasma of MS patients during relapse. Deficiency or pharmacologic blockade of FXII renders mice less susceptible to experimental autoimmune encephalomyelitis (a model of MS) and is accompanied by reduced numbers of interleukin-17A-producing T cells. Immune activation by FXII is mediated by dendritic cells in a CD87-dependent manner and involves alterations in intracellular cyclic AMP formation. Our study demonstrates that a member of the plasmatic coagulation cascade is a key mediator of autoimmunity. FXII inhibition may provide a strategy to combat MS and other immune-related disorders. KW - blood coagulation KW - factor XII KW - neuroinflammation KW - dendric cells Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165503 VL - 7 IS - 11626 ER - TY - JOUR A1 - Hansen, Niels A1 - Seiler, Carola A1 - Rumpf, Julian A1 - Kraft, Peter A1 - Dlaske, Henry A1 - Abele-Horn, Marianne A1 - Muellges, Wolfgang T1 - Human Tuberculous Meningitis Caused by \(Mycobacterium\) \(caprae\) JF - Case Reports in Neurology N2 - INTRODUCTION: Tuberculous meningitis (TM) causes substantial morbidity and mortality in humans. Human TM has been known to be induced by bacteria from the Mycobacterium tuberculosis complex (MTBC), such as M. tuberculosis and M. bovis. CASE PRESENTATION: We describe a case of meningitis treated with fosfomycin, which showed partial effectiveness in an 80-year-old patient. After a lethal myocardial infarction, M. caprae (MC) was identified in cerebrospinal fluid culture. This isolated acid-fast organism was first identified as MTBC by MTBC-specific PCR (16S rDNA-PCR). Furthermore, species-specific identification of the isolate was done by gyrB PCR-restriction fragment length polymorphism analysis of a part of gyrB DNA. Colony morphology of the isolated MC strain showed dysgonic growth on Lowenstein-Jensen medium. The strain was susceptible to pyrazinamide (PZA). CONCLUSION: This isolated strain was convincingly identified as MC according to the phenotypic and genotypic characteristics and PZA sensitivity. This is the first report of MC causing TM. KW - Mycobacterium caprae KW - Mycobacterium caprae KW - fosfomycin KW - Tuberkulose KW - Mycobacterium tuberculosis complex KW - tuberculous meningitis KW - cerebrospinal fluid culture Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123425 VL - 4 IS - 1 ER - TY - JOUR A1 - Heuschmann, Peter U. A1 - Montellano, Felipe A. A1 - Ungethüm, Kathrin A1 - Rücker, Viktoria A1 - Wiedmann, Silke A1 - Mackenrodt, Daniel A1 - Quilitzsch, Anika A1 - Ludwig, Timo A1 - Kraft, Peter A1 - Albert, Judith A1 - Morbach, Caroline A1 - Frantz, Stefan A1 - Störk, Stefan A1 - Haeusler, Karl Georg A1 - Kleinschnitz, Christoph T1 - Prevalence and determinants of systolic and diastolic cardiac dysfunction and heart failure in acute ischemic stroke patients: The SICFAIL study JF - ESC Heart Failure N2 - Aims Ischaemic stroke (IS) might induce alterations of cardiac function. Prospective data on frequency of cardiac dysfunction and heart failure (HF) after IS are lacking. We assessed prevalence and determinants of diastolic dysfunction (DD), systolic dysfunction (SD), and HF in patients with acute IS. Methods and results The Stroke‐Induced Cardiac FAILure in mice and men (SICFAIL) study is a prospective, hospital‐based cohort study. Patients with IS underwent a comprehensive assessment of cardiac function in the acute phase (median 4 days after IS) including clinical examination, standardized transthoracic echocardiography by expert sonographers, and determination of blood‐based biomarkers. Information on demographics, lifestyle, risk factors, symptoms suggestive of HF, and medical history was collected by a standardized personal interview. Applying current guidelines, cardiac dysfunction was classified based on echocardiographic criteria into SD (left ventricular ejection fraction < 52% in men or <54% in women) and DD (≥3 signs of DD in patients without SD). Clinically overt HF was classified into HF with reduced, mid‐range, or preserved ejection fraction. Between January 2014 and February 2017, 696 IS patients were enrolled. Of them, patients with sufficient echocardiographic data on SD were included in the analyses {n = 644 patients [median age 71 years (interquartile range 60–78), 61.5% male]}. In these patients, full assessment of DD was feasible in 549 patients without SD (94%). Prevalence of cardiac dysfunction and HF was as follows: SD 9.6% [95% confidence interval (CI) 7.6–12.2%]; DD in patients without SD 23.3% (95% CI 20.0–27.0%); and clinically overt HF 5.4% (95% CI 3.9–7.5%) with subcategories of HF with preserved ejection fraction 4.35%, HF with mid‐range ejection fraction 0.31%, and HF with reduced ejection fraction 0.78%. In multivariable analysis, SD and fulfilment of HF criteria were associated with history of coronary heart disease [SD: odds ratio (OR) 3.87, 95% CI 1.93–7.75, P = 0.0001; HF: OR 2.29, 95% CI 1.04–5.05, P = 0.0406] and high‐sensitive troponin T at baseline (SD: OR 1.78, 95% CI 1.31–2.42, P = 0.0003; HF: OR 1.66, 95% CI 1.17–2.33, P = 0.004); DD was associated with older age (OR 1.08, 95% CI 1.05–1.11, P < 0.0001) and treated hypertension vs. no hypertension (OR 2.84, 95% CI 1.23–6.54, P = 0.0405). Conclusions A substantial proportion of the study population exhibited subclinical and clinical cardiac dysfunction. SICFAIL provides reliable data on prevalence and determinants of SD, DD, and clinically overt HF in patients with acute IS according to current guidelines, enabling further clarification of its aetiological and prognostic role. KW - Stroke KW - Heart failure KW - Cardiac dysfunction| Brain natriuretic peptide KW - Troponin Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225656 VL - 8 IS - 2 ER - TY - JOUR A1 - Hohmann, Christopher A1 - Milles, Bianca A1 - Schinke, Michael A1 - Schroeter, Michael A1 - Ulzheimer, Jochen A1 - Kraft, Peter A1 - Kleinschnitz, Christoph A1 - Lehmann, Paul V. A1 - Kuerten, Stefanie T1 - Categorization of multiple sclerosis relapse subtypes by B cell profiling in the blood JF - Acta Neuropathologica Communications N2 - INTRODUCTION: B cells are attracting increasing attention in the pathogenesis of multiple sclerosis (MS). B cell-targeted therapies with monoclonal antibodies or plasmapheresis have been shown to be successful in a subset of patients. Here, patients with either relapsing-remitting (n = 24) or secondary progressive (n = 6) MS presenting with an acute clinical relapse were screened for their B cell reactivity to brain antigens and were re-tested three to nine months later. Enzyme-linked immunospot technique (ELISPOT) was used to identify brain-reactive B cells in peripheral blood mononuclear cells (PBMC) directly ex vivo and after 96 h of polyclonal stimulation. Clinical severity of symptoms was determined using the Expanded Disability Status Scale (EDSS). RESULTS: Nine patients displayed B cells in the blood producing brain-specific antibodies directly ex vivo. Six patients were classified as B cell positive donors only after polyclonal B cell stimulation. In 15 patients a B cell response to brain antigens was absent. Based on the autoreactive B cell response we categorized MS relapses into three different patterns. Patients who displayed brain-reactive B cell responses both directly ex vivo and after polyclonal stimulation (pattern I) were significantly younger than patients in whom only memory B cell responses were detectable or entirely absent (patterns II and III; p = 0.003). In one patient a conversion to a positive B cell response as measured directly ex vivo and subsequently also after polyclonal stimulation was associated with the development of a clinical relapse. The evaluation of the predictive value of a brain antigen-specific B cell response showed that seven of eight patients (87.5%) with a pattern I response encountered a clinical relapse during the observation period of 10 months, compared to two of five patients (40%) with a pattern II and three of 14 patients (21.4%) with a pattern III response (p = 0.0005; hazard ratio 6.08 (95% confidence interval 1.87-19.77). CONCLUSIONS: Our data indicate actively ongoing B cell-mediated immunity against brain antigens in a subset of MS patients that may be causative of clinical relapses and provide new diagnostic and therapeutic options for a subset of patients. KW - ELISPOT KW - MS KW - predictive value KW - relapse KW - B cells Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120580 SN - 2051-5960 VL - 2 IS - 138 ER -