@phdthesis{Rosen2005, author = {Rosen, Sandra}, title = {Der Einsatz von Abciximab (ReoPro®) in der Akutbehandlung von isch{\"a}mischen Hirninfarkten mit und ohne vorangehende Thrombolysebehandlung mit rt-PA}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-17514}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {Abciximab wurde, in Phase II-Studien, in der Behandlung der akuten cerebralen Isch{\"a}mie erprobt und es erscheint bisher sicher und effektiv. Obwohl die Effektivit{\"a}t in der Abciximab in Acute Ischemic Stroke Studie nicht prospektiv untersucht wurde, ist jedoch ein Trend zu einem verbessertem Outcome zu beobachten. In unserer Untersuchung wurden 65 Patienten mit cerebralen Isch{\"a}mien in verschiedenen Gef{\"a}ßterritorien mit Abciximab behandelt. Die Patienten zeigten entweder Zeichen und Symptome einer Crescendo-TIA, eines progressive stroke außerhalb des "3-Stunden-Zeitfensters" f{\"u}r eine Thrombolyse oder eine erneute Verschlechterung nach zun{\"a}chst erfolgreicher Thrombolyse. Alle Patienten wurden anhand der modified Rankin Scale (mRS) zum Zeitpunkt des Eintreffens in der Klinik und am Tag der Entlassung von der Stroke Unit untersucht. Ergebnisse: 88\% der Patienten (57/65) verbesserten sich um im Mittel 2,3 Punkte bezogen auf die mRS. 71\% der Patienten (46/65) erreichten eine mRS von 0-2. Es wurden keine fatalen oder symptomatischen intracerebralen Blutungen beobachtet. Fazit: In dieser nicht-randomisierten Untersuchung {\"u}ber die Akuttherapie der cerebralen Isch{\"a}mie, zeigte die Behandlung mit Abciximab alleine oder in Kombination mit Thrombolyse eine klinische Verbesserung in 88\% der Patienten. Blutungskomplikationen waren selten und nie schwerwiegend. Diese Ergebnisse unterst{\"u}tzen die Forderung nach weiteren placebokontrollierten, randomisierten Studien von Abciximab in der Akutbehandlung der cerebralen Isch{\"a}mie.}, language = {de} } @article{MinnerupSutherlandBuchanetal.2012, author = {Minnerup, Jens and Sutherland, Brad A. and Buchan, Alastair M. and Kleinschnitz, Christoph}, title = {Neuroprotection for Stroke: Current Status and Future Perspectives}, series = {International Journal of Molecular Science}, volume = {13}, journal = {International Journal of Molecular Science}, number = {9}, doi = {10.3390/ijms130911753}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134730}, pages = {11753-11772}, year = {2012}, abstract = {Neuroprotection aims to prevent salvageable neurons from dying. Despite showing efficacy in experimental stroke studies, the concept of neuroprotection has failed in clinical trials. Reasons for the translational difficulties include a lack of methodological agreement between preclinical and clinical studies and the heterogeneity of stroke in humans compared to homogeneous strokes in animal models. Even when the international recommendations for preclinical stroke research, the Stroke Academic Industry Roundtable (STAIR) criteria, were followed, we have still seen limited success in the clinic, examples being NXY-059 and haematopoietic growth factors which fulfilled nearly all the STAIR criteria. However, there are a number of neuroprotective treatments under investigation in clinical trials such as hypothermia and ebselen. Moreover, promising neuroprotective treatments based on a deeper understanding of the complex pathophysiology of ischemic stroke such as inhibitors of NADPH oxidases and PSD-95 are currently evaluated in preclinical studies. Further concepts to improve translation include the investigation of neuroprotectants in multicenter preclinical Phase III-type studies, improved animal models, and close alignment between clinical trial and preclinical methodologies. Future successful translation will require both new concepts for preclinical testing and innovative approaches based on mechanistic insights into the ischemic cascade.}, language = {en} } @article{KraftDrechslerGunrebenetal.2014, author = {Kraft, Peter and Drechsler, Christiane and Gunreben, Ignaz and Heuschmann, Peter Ulrich and Kleinschnitz, Christoph}, title = {Regulation of Blood Coagulation Factors XI and XII in Patients with Acute and Chronic Cerebrovascular Disease: A Case-Control Study}, series = {Cerebrovascular Diseases}, volume = {38}, journal = {Cerebrovascular Diseases}, number = {5}, issn = {1015-9770}, doi = {10.1159/000368434}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199076}, pages = {337-343}, year = {2014}, abstract = {Background: Animal models have implicated an integral role for coagulation factors XI (FXI) and XII (FXII) in thrombus formation and propagation of ischemic stroke (IS). However, it is unknown if these molecules contribute to IS pathophysiology in humans, and might be of use as biomarkers for IS risk and severity. This study aimed to identify predictors of altered FXI and FXII levels and to determine whether there are differences in the levels of these coagulation factors between acute cerebrovascular events and chronic cerebrovascular disease (CCD). Methods: In this case-control study, 116 patients with acute ischemic stroke (AIS) or transitory ischemic attack (TIA), 117 patients with CCD, and 104 healthy volunteers (HVs) were enrolled between 2010 and 2013 at our University hospital. Blood sampling was undertaken once in the CCD and HV groups and on days 0, 1, and 3 after stroke onset in patients with AIS or TIA. Correlations between serum FXI and FXII levels and demographic and clinical parameters were tested by linear regression and analysis of variance. Results: The mean age of AIS/TIA patients was 70 ± 12. Baseline clinical severity measured with NIHSS and Barthel Index was 4.8 ± 6.0 and 74 ± 30, respectively. More than half of the patients had an AIS (58\%). FXI levels were significantly correlated with different leukocyte subsets (p < 0.05). In contrast, FXII serum levels showed no significant correlation (p > 0.1). Neither FXI nor FXII levels correlated with CRP (p > 0.2). FXII levels were significantly higher in patients with CCD compared with those with AIS/TIA (mean ± SD 106 ± 26\% vs. 97 ± 24\%; univariate analysis: p < 0.05); these differences did not reach significance in multivariate analysis adjusted for sex and age. FXI levels did not differ significantly between study groups. Sex and age were significantly associated with FXI and/or FXII levels in patients with AIS/TIA (p < 0.05). In contrast, no statistical significant influence was found for treatment modality (thrombolysis or not), pre-treatment with platelet inhibitors, and severity of stroke. Conclusions: In this study, there was no differential regulation of FXI and FXII levels between disease subtypes but biomarker levels were associated with patient and clinical characteristics. FXI and FXII levels might be no valid biomarker for predicting stroke risk.}, language = {en} } @article{UeceylerHomolaGonzalezetal.2014, author = {{\"U}{\c{c}}eyler, Nurcan and Homola, Gy{\"o}rgy A. and Gonz{\´a}lez, Hans Guerrero and Kramer, Daniela and Wanner, Christoph and Weidemann, Frank and Solymosi, L{\´a}szl{\´o} and Sommer, Claudia}, title = {Increased Arterial Diameters in the Posterior Cerebral Circulation in Men with Fabry Disease}, doi = {10.1371/journal.pone.0087054}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-112614}, year = {2014}, abstract = {A high load of white matter lesions and enlarged basilar arteries have been shown in selected patients with Fabry disease, a disorder associated with an increased stroke risk. We studied a large cohort of patients with Fabry disease to differentially investigate white matter lesion load and cerebral artery diameters. We retrospectively analyzed cranial magnetic resonance imaging scans of 87 consecutive Fabry patients, 20 patients with ischemic stroke, and 36 controls. We determined the white matter lesion load applying the Fazekas score on fluid-attenuated inversion recovery sequences and measured the diameters of cerebral arteries on 3D-reconstructions of the time-of-flight-MR-angiography scans. Data of different Fabry patient subgroups (males - females; normal - impaired renal function) were compared with data of patients with stroke and controls. A history of stroke or transient ischemic attacks was present in 4/30 males (13\%) and 5/57 (9\%) females with Fabry disease, all in the anterior circulation. Only one man with Fabry disease showed confluent cerebral white matter lesions in the Fazekas score assessment (1\%). Male Fabry patients had a larger basilar artery (p<0.01) and posterior cerebral artery diameter (p<0.05) compared to male controls. This was independent of disease severity as measured by renal function and did not lead to changes in arterial blood flow properties. A basilar artery diameter of >3.2 mm distinguished between men with Fabry disease and controls (sensitivity: 87\%, specificity: 86\%, p<0.001), but not from stroke patients. Enlarged arterial diameters of the posterior circulation are present only in men with Fabry disease independent of disease severity.}, language = {en} } @article{KraftDrechslerGunrebenetal.2014, author = {Kraft, Peter and Drechsler, Christiane and Gunreben, Ignaz and Nieswandt, Bernhard and Stoll, Guido and Heuschmann, Peter Ulrich and Kleinschnitz, Christoph}, title = {Von Willebrand Factor Regulation in Patients with Acute and Chronic Cerebrovascular Disease: A Pilot, Case-Control Study}, series = {PLoS ONE}, volume = {9}, journal = {PLoS ONE}, number = {6}, issn = {1932-6203}, doi = {10.1371/journal.pone.0099851}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119588}, pages = {e99851}, year = {2014}, abstract = {Background and Purpose In animal models, von Willebrand factor (VWF) is involved in thrombus formation and propagation of ischemic stroke. However, the pathophysiological relevance of this molecule in humans, and its potential use as a biomarker for the risk and severity of ischemic stroke remains unclear. This study had two aims: to identify predictors of altered VWF levels and to examine whether VWF levels differ between acute cerebrovascular events and chronic cerebrovascular disease (CCD). Methods A case-control study was undertaken between 2010 and 2013 at our University clinic. In total, 116 patients with acute ischemic stroke (AIS) or transitory ischemic attack (TIA), 117 patients with CCD, and 104 healthy volunteers (HV) were included. Blood was taken at days 0, 1, and 3 in patients with AIS or TIA, and once in CCD patients and HV. VWF serum levels were measured and correlated with demographic and clinical parameters by multivariate linear regression and ANOVA. Results Patients with CCD (158±46\%) had significantly higher VWF levels than HV (113±36\%, P<0.001), but lower levels than AIS/TIA patients (200±95\%, P<0.001). Age, sex, and stroke severity influenced VWF levels (P<0.05). Conclusions VWF levels differed across disease subtypes and patient characteristics. Our study confirms increased VWF levels as a risk factor for cerebrovascular disease and, moreover, suggests that it may represent a potential biomarker for stroke severity, warranting further investigation.}, language = {en} } @article{KraftDrechslerSchuhmannetal.2015, author = {Kraft, Peter and Drechsler, Christiane and Schuhmann, Michael K. and Gunreben, Ignaz and Kleinschnitz, Christoph}, title = {Characterization of Peripheral Immune Cell Subsets in Patients with Acute and Chronic Cerebrovascular Disease: A Case-Control Study}, series = {International Journal of Molecular Science}, volume = {16}, journal = {International Journal of Molecular Science}, number = {10}, doi = {10.3390/ijms161025433}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126319}, pages = {25433-25449}, year = {2015}, abstract = {Immune cells (IC) play a crucial role in murine stroke pathophysiology. However, data are limited on the role of these cells in ischemic stroke in humans. We therefore aimed to characterize and compare peripheral IC subsets in patients with acute ischemic stroke/transient ischemic attack (AIS/TIA), chronic cerebrovascular disease (CCD) and healthy volunteers (HV). We conducted a case-control study of patients with AIS/TIA (n = 116) or CCD (n = 117), and HV (n = 104) who were enrolled at the University Hospital W{\"u}rzburg from 2010 to 2013. We determined the expression and quantity of IC subsets in the three study groups and performed correlation analyses with demographic and clinical parameters. The quantity of several IC subsets differed between the AIS/TIA, CCD, and HV groups. Several clinical and demographic variables independently predicted the quantity of IC subsets in patients with AIS/TIA. No significant changes in the quantity of IC subsets occurred within the first three days after AIS/TIA. Overall, these findings strengthen the evidence for a pathophysiologic role of IC in human ischemic stroke and the potential use of IC-based biomarkers for the prediction of stroke risk. A comprehensive description of IC kinetics is crucial to enable the design of targeted treatment strategies.}, language = {en} } @article{WolfBraunHainingetal.2016, author = {Wolf, Karen and Braun, Attila and Haining, Elizabeth J. and Tseng, Yu-Lun and Kraft, Peter and Schuhmann, Michael K. and Gotru, Sanjeev K. and Chen, Wenchun and Hermanns, Heike M. and Stoll, Guido and Lesch, Klaus-Peter and Nieswandt, Bernhard}, title = {Partially Defective Store Operated Calcium Entry and Hem(ITAM) Signaling in Platelets of Serotonin Transporter Deficient Mice}, series = {PLoS One}, volume = {11}, journal = {PLoS One}, number = {1}, doi = {10.1371/journal.pone.0147664}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146399}, pages = {e0147664}, year = {2016}, abstract = {Background Serotonin (5-hydroxytryptamin, 5-HT) is an indolamine platelet agonist, biochemically derived from tryptophan. 5-HT is secreted from the enterochromaffin cells into the gastrointestinal tract and blood. Blood 5-HT has been proposed to regulate hemostasis by acting as a vasoconstrictor and by triggering platelet signaling through 5-HT receptor 2A (5HTR2A). Although platelets do not synthetize 5-HT, they take 5-HT up from the blood and store it in their dense granules which are secreted upon platelet activation. Objective To identify the molecular composite of the 5-HT uptake system in platelets and elucidate the role of platelet released 5-HT in thrombosis and ischemic stroke. Methods: 5-HT transporter knockout mice (5Htt\(^{-/-}\)) were analyzed in different in vitro and in vivo assays and in a model of ischemic stroke. Results In 5Htt\(^{-/-}\) platelets, 5-HT uptake from the blood was completely abolished and agonist-induced Ca2+ influx through store operated Ca\(^{2+}\) entry (SOCE), integrin activation, degranulation and aggregation responses to glycoprotein VI (GPVI) and C-type lectin-like receptor 2 (CLEC-2) were reduced. These observed in vitro defects in 5Htt\(^{-/-}\) platelets could be normalized by the addition of exogenous 5-HT. Moreover, reduced 5-HT levels in the plasma, an increased bleeding time and the formation of unstable thrombi were observed ex vivo under flow and in vivo in the abdominal aorta and carotid artery of 5Htt\(^{-/-}\) mice. Surprisingly, in the transient middle cerebral artery occlusion (tMCAO) model of ischemic stroke 5Htt\(^{-/-}\) mice showed nearly normal infarct volume and the neurological outcome was comparable to control mice. Conclusion Although secreted platelet 5-HT does not appear to play a crucial role in the development of reperfusion injury after stroke, it is essential to amplify the second phase of platelet activation through SOCE and plays an important role in thrombus stabilization.}, language = {en} } @article{SchuhmannGunrebenKleinschnitzetal.2016, author = {Schuhmann, Michael K. and Gunreben, Ignaz and Kleinschnitz, Christoph and Kraft, Peter}, title = {Immunohistochemical Analysis of Cerebral Thrombi Retrieved by Mechanical Thrombectomy from Patients with Acute Ischemic Stroke}, series = {International Journal of Molecular Sciences}, volume = {17}, journal = {International Journal of Molecular Sciences}, number = {3}, doi = {10.3390/ijms17030298}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166206}, pages = {298}, year = {2016}, abstract = {Mechanical thrombectomy is a novel treatment option for patients with acute ischemic stroke (AIS). Only a few studies have previously suggested strategies to categorize retrieved clots according to their histologic composition. However, these reports did not analyze potential biomarkers that are of importance in stroke-related inflammation. We therefore histopathologically investigated 37 intracerebral thrombi mechanically retrieved from patients with AIS, and focused on the composition of immune cells and platelets. We also conducted correlation analyses of distinctive morphologic patterns (erythrocytic, serpentine, layered, red, white, mixed appearance) with clinical parameters. Most T cells and monocytes were detected in erythrocytic and red clots, in which the distribution of these cells was random. In contrast, von Willebrand factor (vWF)-positive areas co-localized with regions of fibrin and collagen. While clots with huge amounts of vWF seem to be associated with a high National Institute of Health Stroke Scale score at admission, histologic findings could not predict the clinical outcome at discharge. In summary, we provide the first histologic description of mechanically retrieved intracerebral thrombi regarding biomarkers relevant for inflammation in ischemic stroke.}, language = {en} } @article{KrupkaMayWeimeretal.2016, author = {Krupka, Jennifer and May, Frauke and Weimer, Thomas and Pragst, Ingo and Kleinschnitz, Christoph and Stoll, Guido and Panousis, Con and Dickneite, Gerhard and Nolte, Marc W.}, title = {The Coagulation Factor XIIa Inhibitor rHA-Infestin-4 Improves Outcome after Cerebral Ischemia/Reperfusion Injury in Rats}, series = {PLoS ONE}, volume = {11}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0146783}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167370}, pages = {e0146783}, year = {2016}, abstract = {Background and Purpose Ischemic stroke provokes severe brain damage and remains a predominant disease in industrialized countries. The coagulation factor XII (FXII)-driven contact activation system plays a central, but not yet fully defined pathogenic role in stroke development. Here, we investigated the efficacy of the FXIIa inhibitor rHA-Infestin-4 in a rat model of ischemic stroke using both a prophylactic and a therapeutic approach. Methods For prophylactic treatment, animals were treated intravenously with 100 mg/kg rHA-Infestin-4 or an equal volume of saline 15 min prior to transient middle cerebral artery occlusion (tMCAO) of 90 min. For therapeutic treatment, 100 mg/kg rHA-Infestin-4, or an equal volume of saline, was administered directly after the start of reperfusion. At 24 h after tMCAO, rats were tested for neurological deficits and blood was drawn for coagulation assays. Finally, brains were removed and analyzed for infarct area and edema formation. Results Within prophylactic rHA-Infestin-4 treatment, infarct areas and brain edema formation were reduced accompanied by better neurological scores and survival compared to controls. Following therapeutic treatment, neurological outcome and survival were still improved although overall effects were less pronounced compared to prophylaxis. Conclusions With regard to the central role of the FXII-driven contact activation system in ischemic stroke, inhibition of FXIIa may represent a new and promising treatment approach to prevent cerebral ischemia/reperfusion injury.}, language = {en} } @article{KraftFleischerWiedmannetal.2017, author = {Kraft, Peter and Fleischer, Anna and Wiedmann, Silke and R{\"u}cker, Viktoria and Mackenrodt, Daniel and Morbach, Caroline and Malzahn, Uwe and Kleinschnitz, Christoph and St{\"o}rk, Stefan and Heuschmann, Peter U.}, title = {Feasibility and diagnostic accuracy of point-of-care handheld echocardiography in acute ischemic stroke patients - a pilot study}, series = {BMC Neurology}, volume = {17}, journal = {BMC Neurology}, number = {159}, doi = {10.1186/s12883-017-0937-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158081}, year = {2017}, abstract = {Background: Standard echocardiography (SE) is an essential part of the routine diagnostic work-up after ischemic stroke (IS) and also serves for research purposes. However, access to SE is often limited. We aimed to assess feasibility and accuracy of point-of-care (POC) echocardiography in a stroke unit (SU) setting. Methods: IS patients were recruited on the SU of the University Hospital W{\"u}rzburg, Germany. Two SU team members were trained in POC echocardiography for a three-month period to assess a set of predefined cardiac parameters including left ventricular ejection fraction (LVEF). Diagnostic agreement was assessed by comparing POC with SE executed by an expert sonographer, and intraclass correlation coefficient (ICC) or kappa (κ) with 95\% confidence intervals (95\% CI) were calculated. Results: In the 78 patients receiving both POC and SE agreement for cardiac parameters was good, with ICC varying from 0.82 (95\% CI 0.71-0.89) to 0.93 (95\% CI 0.87-0.96), and κ from 0.39 (-95\% CI 0.14-0.92) to 0.79 (95\% CI 0.67-0.91). Detection of systolic dysfunction with POC echocardiography compared to SE was very good, with an area under the curve of 0.99 (0.96-1.00). Interrater agreement for LVEF measured by POC echocardiography was good with κ 0.63 (95\% CI 0.40-0.85). Conclusions: POC echocardiography in a SU setting is feasible enabling reliable quantification of LVEF and preliminary assessment of selected cardiac parameters that might be used for research purposes. Its potential clinical utility in triaging stroke patients who should undergo or do not necessarily require SE needs to be investigated in larger prospective diagnostic studies.}, language = {en} } @article{SchuhmannGuthmannStolletal.2017, author = {Schuhmann, Michael K. and Guthmann, Josua and Stoll, Guido and Nieswandt, Bernhard and Kraft, Peter and Kleinschnitz, Christoph}, title = {Blocking of platelet glycoprotein receptor Ib reduces "thrombo-inflammation" in mice with acute ischemic stroke}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {18}, doi = {10.1186/s12974-017-0792-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157582}, year = {2017}, abstract = {Background: Ischemic stroke causes a strong inflammatory response that includes T cells, monocytes/macrophages, and neutrophils. Interaction of these immune cells with platelets and endothelial cells facilitates microvascular dysfunction and leads to secondary infarct growth. We recently showed that blocking of platelet glycoprotein (GP) receptor Ib improves stroke outcome without increasing the risk of intracerebral hemorrhage. Until now, it has been unclear whether GPIb only mediates thrombus formation or also contributes to the pathophysiology of local inflammation. Methods: Focal cerebral ischemia was induced in C57BL/6 mice by a 60-min transient middle cerebral artery occlusion (tMCAO). Animals were treated with antigen-binding fragments (Fab) against the platelet surface molecules GPIb (p0p/B Fab). Rat immunoglobulin G (IgG) Fab was used as control treatment. Stroke outcome, including infarct size and functional deficits as well as the local inflammatory response, was assessed on day 1 after tMCAO. Results: Blocking of GPIb reduced stroke size and improved functional outcome on day 1 after tMCAO without increasing the risk of intracerebral hemorrhage. As expected, disruption of GPIb-mediated pathways in platelets significantly reduced thrombus burden in the cerebral microvasculature. In addition, inhibition of GPIb limited the local inflammatory response in the ischemic brain as indicated by lower numbers of infiltrating T cells and macrophages and lower expression levels of inflammatory cytokines compared with rat IgG Fab-treated controls. Conclusion: In acute ischemic stroke, thrombus formation and inflammation are closely intertwined ("thrombo-inflammation"). Blocking of platelet GPIb can ameliorate thrombo-inflammation.}, language = {en} } @article{SchuhmannLanghauserKraftetal.2017, author = {Schuhmann, Michael K. and Langhauser, Friederike and Kraft, Peter and Kleinschnitz, Christoph}, title = {B cells do not have a major pathophysiologic role in acute ischemic stroke in mice}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {112}, doi = {10.1186/s12974-017-0890-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158155}, year = {2017}, abstract = {Background Lymphocytes have been shown to play an important role in the pathophysiology of acute ischemic stroke, but the properties of B cells remain controversial. The aim of this study was to unravel the role of B cells during acute cerebral ischemia using pharmacologic B cell depletion, B cell transgenic mice, and adoptive B cell transfer experiments. Methods Transient middle cerebral artery occlusion (60 min) was induced in wild-type mice treated with an anti-CD20 antibody 24 h before stroke onset, JHD\(^{-/-}\) mice and Rag1\(^{-/-}\) mice 24 h after adoptive B cell transfer. Stroke outcome was assessed at days 1 and 3. Infarct volumes were calculated from 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections, and neurological scores were evaluated. The local inflammatory response was determined by real-time PCR and immunohistochemistry. Apoptosis was analyzed by TUNEL staining, and astrocyte activation was revealed using immunohistochemistry and Western blot. Results Pharmacologic depletion of B cells did not influence infarct volumes and functional outcome at day 1 after stroke. Additionally, lack of circulating B cells in JHD\(^{-/-}\) mice also failed to influence stroke outcome at days 1 and 3. Furthermore, reconstitution of Rag1\(^{-/-}\) mice with B cells had no influence on infarct volumes. Conclusion Targeting B cells in experimental stroke did not influence lesion volume and functional outcome during the acute phase. Our findings argue against a major pathophysiologic role of B cells during acute ischemic stroke.}, language = {en} } @article{ElhfnawyHeuschmannPhametal.2019, author = {Elhfnawy, Ahmed Mohamed and Heuschmann, Peter U. and Pham, Mirko and Volkmann, Jens and Fluri, Felix}, title = {Stenosis length and degree interact with the risk of cerebrovascular events related to internal carotid artery stenosis}, series = {Frontiers in Neurology}, volume = {10}, journal = {Frontiers in Neurology}, number = {317}, issn = {1664-2295}, doi = {10.3389/fneur.2019.00317}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196225}, year = {2019}, abstract = {Background and Purpose: Internal carotid artery stenosis (ICAS)≥70\% is a leading cause of ischemic cerebrovascular events (ICVEs). However, a considerable percentage of stroke survivors with symptomatic ICAS (sICAS) have <70\% stenosis with a vulnerable plaque. Whether the length of ICAS is associated with high risk of ICVEs is poorly investigated. Our main aim was to investigate the relation between the length of ICAS and the development of ICVEs. Methods: In a retrospective cross-sectional study, we identified 95 arteries with sICAS and another 64 with asymptomatic internal carotid artery stenosis (aICAS) among 121 patients with ICVEs. The degree and length of ICAS as well as plaque echolucency were assessed on ultrasound scans. Results: A statistically significant inverse correlation between the ultrasound-measured length and degree of ICAS was detected for sICAS≥70\% (Spearman correlation coefficient ρ = -0.57, p < 0.001, n = 51) but neither for sICAS<70\% (ρ = 0.15, p = 0.45, n = 27) nor for aICAS (ρ = 0.07, p = 0.64, n = 54). The median (IQR) length for sICAS<70\% and ≥70\% was 17 (15-20) and 15 (12-19) mm (p = 0.06), respectively, while that for sICAS<90\% and sICAS 90\% was 18 (15-21) and 13 (10-16) mm, respectively (p < 0.001). Among patients with ICAS <70\%, a cut-off length of ≥16 mm was found for sICAS rather than aICAS with a sensitivity and specificity of 74.1\% and 51.1\%, respectively. Irrespective of the stenotic degree, plaques of the sICAS compared to aICAS were significantly more often echolucent (43.2 vs. 24.6\%, p = 0.02). Conclusion: We found a statistically insignificant tendency for the ultrasound-measured length of sICAS<70\% to be longer than that of sICAS≥70\%. Moreover, the ultrasound-measured length of sICAS<90\% was significantly longer than that of sICAS 90\%. Among patients with sICAS≥70\%, the degree and length of stenosis were inversely correlated. Larger studies are needed before a clinical implication can be drawn from these results.}, language = {en} } @article{SchuhmannKraftBieberetal.2019, author = {Schuhmann, Michael K. and Kraft, Peter and Bieber, Michael and Kollikowski, Alexander M. and Schulze, Harald and Nieswandt, Bernhard and Pham, Mirko and Stegner, David and Stoll, Guido}, title = {Targeting platelet GPVI plus rt-PA administration but not α2β1-mediated collagen binding protects against ischemic brain damage in mice}, series = {International Journal of Molecular Science}, volume = {20}, journal = {International Journal of Molecular Science}, number = {8}, issn = {1422-0067}, doi = {10.3390/ijms20082019}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201700}, year = {2019}, abstract = {Platelet collagen interactions at sites of vascular injuries predominantly involve glycoprotein VI (GPVI) and the integrin α2β1. Both proteins are primarily expressed on platelets and megakaryocytes whereas GPVI expression is also shown on endothelial and integrin α2β1 expression on epithelial cells. We recently showed that depletion of GPVI improves stroke outcome without increasing the risk of cerebral hemorrhage. Genetic variants associated with higher platelet surface integrin α2 (ITGA2) receptor levels have frequently been found to correlate with an increased risk of ischemic stroke in patients. However until now, no preclinical stroke study has addressed whether platelet integrin α2β1 contributes to the pathophysiology of ischemia/reperfusion (I/R) injury. Focal cerebral ischemia was induced in C57BL/6 and Itga2\(^{-/-}\) mice by a 60 min transient middle cerebral artery occlusion (tMCAO). Additionally, wild-type animals were pretreated with anti-GPVI antibody (JAQ1) or Fab fragments of a function blocking antibody against integrin α2β1 (LEN/B). In anti-GPVI treated animals, intravenous (IV) recombinant tissue plasminogen activator (rt-PA) treatment was applied immediately prior to reperfusion. Stroke outcome, including infarct size and neurological scoring was determined on day 1 after tMCAO. We demonstrate that targeting the integrin α2β1 (pharmacologic; genetic) did neither reduce stroke size nor improve functional outcome on day 1 after tMCAO. In contrast, depletion of platelet GPVI prior to stroke was safe and effective, even when combined with rt-PA treatment. Our results underscore that GPVI, but not ITGA2, is a promising and safe target in the setting of ischemic stroke.}, language = {en} } @article{ElhfnawyVolkmannSchliesseretal.2019, author = {Elhfnawy, Ahmed Mohamed and Volkmann, Jens and Schliesser, Mira and Fluri, Felix}, title = {Symptomatic vs. asymptomatic 20-40\% internal carotid artery stenosis: Does the plaque size matter?}, series = {Frontiers in Neurology}, volume = {10}, journal = {Frontiers in Neurology}, number = {960}, doi = {10.3389/fneur.2019.00960}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201262}, year = {2019}, abstract = {Background: Around 9-15\% of ischemic strokes are related to internal carotid artery (ICA)-stenosis ≥50\%. However, the extent to which ICA-stenosis <50\% causes ischemic cerebrovascular events is uncertain. We examined the relation between plaque cross-sectional area and length and the risk of ischemic stroke or TIA among patients with ICA-stenosis of 20-40\%. Methods: We retrospectively identified patients admitted to the Department of Neurology, University Hospital of W{\"u}rzburg, from January 2011 until September 2016 with ischemic stroke or TIA and concomitant ICA-stenosis of 20-40\%, either symptomatic or asymptomatic. Plaque length and cross-sectional area were assessed on ultrasound scans. Results: We identified 41 patients with ischemic stroke or TIA and ICA-stenosis of 20-40\%; 14 symptomatic and 27 asymptomatic. The plaque cross-sectional area was significantly larger among symptomatic than asymptomatic ICA-stenosis; median values (IQR) were 0.45 (0.21-0.69) cm2 and 0.27 (0.21-0.38) cm2, p = 0.03, respectively. A plaque cross-sectional area ≥0.36 cm2 had a sensitivity of 71\% and a specificity of 76\% for symptomatic compared with asymptomatic ICA-stenosis. In a sex-adjusted multivariate logistic regression, a plaque cross-sectional area ≥0.36 cm2 and a plaque length ≥1.65 cm were associated with an OR (95\% CI) of 5.54 (1.2-25.6), p = 0.028 and 1.78 (0.36-8.73), p = 0.48, respectively, for symptomatic ICA-stenosis. Conclusion: Large plaques might increase the risk of ischemic stroke or TIA among patients with low-grade ICA-stenosis of 20-40\%. Sufficiently powered prospective longitudinal cohort studies are needed to definitively test the stroke risk stratification value of carotid plaque length and cross-sectional area in the setting of current optimal medical treatment.}, language = {en} } @article{GabrielJirůHillmannKraftetal.2020, author = {Gabriel, Katharina M. A. and J{\´i}rů-Hillmann, Steffi and Kraft, Peter and Selig, Udo and R{\"u}cker, Victoria and M{\"u}hler, Johannes and D{\"o}tter, Klaus and Keidel, Matthias and Soda, Hassan and Rascher, Alexandra and Schneider, Rolf and Pfau, Mathias and Hoffmann, Roy and Stenzel, Joachim and Benghebrid, Mohamed and Goebel, Tobias and Doerck, Sebastian and Kramer, Daniela and Haeusler, Karl Georg and Volkmann, Jens and Heuschmann, Peter U. and Fluri, Felix}, title = {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)}, series = {BMC Neurology}, volume = {20}, journal = {BMC Neurology}, doi = {10.1186/s12883-020-01676-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229214}, year = {2020}, abstract = {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.}, language = {en} } @article{SchnabelCamenKnebeletal.2021, author = {Schnabel, Renate B. and Camen, Stephan and Knebel, Fabian and Hagendorff, Andreas and Bavendiek, Udo and B{\"o}hm, Michael and Doehner, Wolfram and Endres, Matthias and Gr{\"o}schel, Klaus and Goette, Andreas and Huttner, Hagen B. and Jensen, Christoph and Kirchhof, Paulus and Korosoglou, Grigorius and Laufs, Ulrich and Liman, Jan and Morbach, Caroline and Navabi, Darius G{\"u}nther and Neumann-Haefelin, Tobias and Pfeilschifter, Waltraut and Poli, Sven and Rizos, Timolaos and Rolf, Andreas and R{\"o}ther, Joachim and Sch{\"a}bitz, Wolf R{\"u}diger and Steiner, Thorsten and Thomalla, G{\"o}tz and Wachter, Rolf and Haeusler, Karl Georg}, title = {Expert opinion paper on cardiac imaging after ischemic stroke}, series = {Clinical Research in Cardiology}, volume = {110}, journal = {Clinical Research in Cardiology}, number = {7}, issn = {1861-0692}, doi = {10.1007/s00392-021-01834-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266662}, pages = {938-958}, year = {2021}, abstract = {This expert opinion paper on cardiac imaging after acute ischemic stroke or transient ischemic attack (TIA) includes a statement of the "Heart and Brain" consortium of the German Cardiac Society and the German Stroke Society. The Stroke Unit-Commission of the German Stroke Society and the German Atrial Fibrillation NETwork (AFNET) endorsed this paper. Cardiac imaging is a key component of etiological work-up after stroke. Enhanced echocardiographic tools, constantly improving cardiac computer tomography (CT) as well as cardiac magnetic resonance imaging (MRI) offer comprehensive non- or less-invasive cardiac evaluation at the expense of increased costs and/or radiation exposure. Certain imaging findings usually lead to a change in medical secondary stroke prevention or may influence medical treatment. However, there is no proof from a randomized controlled trial (RCT) that the choice of the imaging method influences the prognosis of stroke patients. Summarizing present knowledge, the German Heart and Brain consortium proposes an interdisciplinary, staged standard diagnostic scheme for the detection of risk factors of cardio-embolic stroke. This expert opinion paper aims to give practical advice to physicians who are involved in stroke care. In line with the nature of an expert opinion paper, labeling of classes of recommendations is not provided, since many statements are based on expert opinion, reported case series, and clinical experience.}, language = {en} } @article{SchuhmannBieberFrankeetal.2021, author = {Schuhmann, Michael K. and Bieber, Michael and Franke, Maximilian and Kollikowski, Alexander M. and Stegner, David and Heinze, Katrin G. and Nieswandt, Bernhard and Pham, Mirko and Stoll, Guido}, title = {Platelets and lymphocytes drive progressive penumbral tissue loss during middle cerebral artery occlusion in mice}, series = {Journal of Neuroinflammation}, volume = {18}, journal = {Journal of Neuroinflammation}, number = {1}, doi = {10.1186/s12974-021-02095-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259172}, pages = {46}, year = {2021}, abstract = {Background In acute ischemic stroke, cessation of blood flow causes immediate tissue necrosis within the center of the ischemic brain region accompanied by functional failure in the surrounding brain tissue designated the penumbra. The penumbra can be salvaged by timely thrombolysis/thrombectomy, the only available acute stroke treatment to date, but is progressively destroyed by the expansion of infarction. The underlying mechanisms of progressive infarction are not fully understood. Methods To address mechanisms, mice underwent filament occlusion of the middle cerebral artery (MCAO) for up to 4 h. Infarct development was compared between mice treated with antigen-binding fragments (Fab) against the platelet surface molecules GPIb (p0p/B Fab) or rat immunoglobulin G (IgG) Fab as control treatment. Moreover, Rag1\(^{-/-}\) mice lacking T-cells underwent the same procedures. Infarct volumes as well as the local inflammatory response were determined during vessel occlusion. Results We show that blocking of the platelet adhesion receptor, glycoprotein (GP) Ibα in mice, delays cerebral infarct progression already during occlusion and thus before recanalization/reperfusion. This therapeutic effect was accompanied by decreased T-cell infiltration, particularly at the infarct border zone, which during occlusion is supplied by collateral blood flow. Accordingly, mice lacking T-cells were likewise protected from infarct progression under occlusion. Conclusions Progressive brain infarction can be delayed by blocking detrimental lymphocyte/platelet responses already during occlusion paving the way for ultra-early treatment strategies in hyper-acute stroke before recanalization.}, language = {en} } @article{EichnerReisDoresetal.2021, author = {Eichner, Felizitas A. and Reis, Joschua M. and Dores, Joaquim and Pavlovic, Vladimir and Kreß, Luisa and Daneshkhah, Naeimeh and Weinhardt, Renate and Grau, Armin and M{\"u}hler, Johannes and Soda, Hassan and Schwarzbach, Christopher J. and Schuler, Michael and H{\"a}usler, Karl Georg and Heuschmann, Peter U.}, title = {Cross-sectional study on patients' understanding and views of the informed consent procedure of a secondary stroke prevention trial}, series = {European Journal of Neurology}, volume = {28}, journal = {European Journal of Neurology}, number = {8}, doi = {10.1111/ene.14917}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259404}, pages = {2639-2647}, year = {2021}, abstract = {Background and purpose Improving understanding of study contents and procedures might enhance recruitment into studies and retention during follow-up. However, data in stroke patients on understanding of the informed consent (IC) procedure are sparse. Methods We conducted a cross-sectional study among ischemic stroke patients taking part in the IC procedure of an ongoing cluster-randomized secondary prevention trial. All aspects of the IC procedure were assessed in an interview using a standardized 20-item questionnaire. Responses were collected within 72 h after the IC procedure and analyzed quantitatively and qualitatively. Participants were also asked their main reasons for participation. Results A total of 146 stroke patients (65 ± 12 years old, 38\% female) were enrolled. On average, patients recalled 66.4\% (95\% confidence interval = 65.2\%-67.5\%) of the content of the IC procedure. Most patients understood that participation was voluntary (99.3\%) and that they had the right to withdraw consent (97.1\%); 79.1\% of the patients recalled the study duration and 56.1\% the goal. Only 40.3\% could clearly state a benefit of participation, and 28.8\% knew their group allocation. Younger age, higher graduation, and allocation to the intervention group were associated with better understanding. Of all patients, 53\% exclusively stated a personal and 22\% an altruistic reason for participation. Conclusions Whereas understanding of patient rights was high, many patients were unable to recall other important aspects of study content and procedures. Increased attention to older and less educated patients may help to enhance understanding in this patient population. Actual recruitment and retention benefit of an improved IC procedure remains to be tested in a randomized trial.}, language = {en} } @article{StrinitzPhamMaerzetal.2021, author = {Strinitz, Marc and Pham, Mirko and M{\"a}rz, Alexander G. and Feick, J{\"o}rn and Weidner, Franziska and Vogt, Marius L. and Essig, Fabian and Neugebauer, Hermann and Stoll, Guido and Schuhmann, Michael K. and Kollikowski, Alexander M.}, title = {Immune cells invade the collateral circulation during human stroke: prospective replication and extension}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {17}, issn = {1422-0067}, doi = {10.3390/ijms22179161}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284281}, year = {2021}, abstract = {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.}, language = {en} } @article{MontellanoKluterRueckeretal.2022, author = {Montellano, Felipe A. and Kluter, Elisabeth J. and R{\"u}cker, Viktoria and Ungeth{\"u}m, Kathrin and Mackenrodt, Daniel and Wiedmann, Silke and Dege, Tassilo and Quilitzsch, Anika and Morbach, Caroline and Frantz, Stefan and St{\"o}rk, Stefan and Haeusler, Karl Georg and Kleinschnitz, Christoph and Heuschmann, Peter U.}, title = {Cardiac dysfunction and high-sensitive C-reactive protein are associated with troponin T elevation in ischemic stroke: insights from the SICFAIL study}, series = {BMC Neurology}, volume = {22}, journal = {BMC Neurology}, number = {1}, doi = {10.1186/s12883-022-03017-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300119}, year = {2022}, abstract = {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, W{\"u}rzburg 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.}, language = {en} } @article{KollikowskiPhamMaerzetal.2022, author = {Kollikowski, Alexander M. and Pham, Mirko and M{\"a}rz, Alexander G. and Papp, Lena and Nieswandt, Bernhard and Stoll, Guido and Schuhmann, Michael K.}, title = {Platelet Activation and Chemokine Release Are Related to Local Neutrophil-Dominant Inflammation During Hyperacute Human Stroke}, series = {Translational Stroke Research}, volume = {13}, journal = {Translational Stroke Research}, number = {3}, issn = {1868-601X}, doi = {10.1007/s12975-021-00938-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270194}, pages = {364-369}, year = {2022}, abstract = {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.}, language = {en} } @article{SchanbacherBieberReindersetal.2022, author = {Schanbacher, Constanze and Bieber, Michael and Reinders, Yvonne and Cherpokova, Deya and Teichert, Christina and Nieswandt, Bernhard and Sickmann, Albert and Kleinschnitz, Christoph and Langhauser, Friederike and Lorenz, Kristina}, title = {ERK1/2 activity is critical for the outcome of ischemic stroke}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {2}, issn = {1422-0067}, doi = {10.3390/ijms23020706}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-283991}, year = {2022}, abstract = {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.}, language = {en} } @article{BellutRaimondiHaarmannetal.2022, author = {Bellut, Maximilian and Raimondi, Anthony T. and Haarmann, Axel and Zimmermann, Lena and Stoll, Guido and Schuhmann, Michael K.}, title = {NLRP3 inhibition reduces rt-PA induced endothelial dysfunction under ischemic conditions}, series = {Biomedicines}, volume = {10}, journal = {Biomedicines}, number = {4}, issn = {2227-9059}, doi = {10.3390/biomedicines10040762}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267261}, year = {2022}, abstract = {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.}, language = {en} } @article{BieberSchuhmannBellutetal.2022, author = {Bieber, Michael and Schuhmann, Michael K. and Bellut, Maximilian and Stegner, David and Heinze, Katrin G. and Pham, Mirko and Nieswandt, Bernhard and Stoll, Guido}, title = {Blockade of platelet glycoprotein Ibα augments neuroprotection in Orai2-deficient mice during middle cerebral artery occlusion}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {16}, issn = {1422-0067}, doi = {10.3390/ijms23169496}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286038}, year = {2022}, abstract = {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.}, language = {en} } @article{TuetuencueOlmaKunzeetal.2022, author = {T{\"u}t{\"u}nc{\"u}, Serdar and Olma, Manuel and Kunze, Claudia and Dietzel, Joanna and Schurig, Johannes and Fiessler, Cornelia and Malsch, Carolin and Haas, Tobias Eberhard and Dimitrijeski, Boris and Doehner, Wolfram and Hagemann, Georg and Hamilton, Frank and Honermann, Martin and Jungehulsing, Gerhard Jan and Kauert, Andreas and Koennecke, Hans-Christian and Mackert, Bruno-Marcel and Nabavi, Darius and Nolte, Christian H. and Reis, Joschua Mirko and Schmehl, Ingo and Sparenberg, Paul and Stingele, Robert and V{\"o}lzke, Enrico and Waldschmidt, Carolin and Zeise-Wehry, Daniel and Heuschmann, Peter U. and Endress, Matthias and Haeusler, Karl Georg}, title = {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}, series = {Journal of Neurology}, volume = {269}, journal = {Journal of Neurology}, number = {1}, issn = {1432-1459}, doi = {10.1007/s00415-021-10866-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266969}, pages = {470-480}, year = {2022}, abstract = {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.}, language = {en} } @article{BellutBieberKraftetal.2023, author = {Bellut, Maximilian and Bieber, Michael and Kraft, Peter and Weber, Alexander N. R. and Stoll, Guido and Schuhmann, Michael K.}, title = {Delayed NLRP3 inflammasome inhibition ameliorates subacute stroke progression in mice}, series = {Journal of Neuroinflammation}, volume = {20}, journal = {Journal of Neuroinflammation}, number = {1}, doi = {10.1186/s12974-022-02674-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300599}, year = {2023}, abstract = {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.}, language = {en} }