@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{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{KraftSchuhmannGarzetal.2017, author = {Kraft, Peter and Schuhmann, Michael K. and Garz, Cornelia and Jandke, Solveig and Urlaub, Daniela and Mencl, Stine and Zernecke, Alma and Heinze, Hans-Jochen and Carare, Roxana O. and Kleinschnitz, Christoph and Schreiber, Stefanie}, title = {Hypercholesterolemia induced cerebral small vessel disease}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {8}, doi = {10.1371/journal.pone.0182822}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170493}, pages = {e0182822}, year = {2017}, abstract = {Background While hypercholesterolemia plays a causative role for the development of ischemic stroke in large vessels, its significance for cerebral small vessel disease (CSVD) remains unclear. We thus aimed to understand the detailed relationship between hypercholesterolemia and CSVD using the well described Ldlr\(^{-/-}\) mouse model. Methods We used Ldlr\(^{-/-}\) mice (n = 16) and wild-type (WT) mice (n = 15) at the age of 6 and 12 months. Ldlr\(^{-/-}\) mice develop high plasma cholesterol levels following a high fat diet. We analyzed cerebral capillaries and arterioles for intravascular erythrocyte accumulations, thrombotic vessel occlusions, blood-brain barrier (BBB) dysfunction and microbleeds. Results We found a significant increase in the number of erythrocyte stases in 6 months old Ldlr\(^{-/-}\) mice compared to all other groups (P < 0.05). Ldlr\(^{-/-}\) animals aged 12 months showed the highest number of thrombotic occlusions while in WT animals hardly any occlusions could be observed (P < 0.001). Compared to WT mice, Ldlr\(^{-/-}\) mice did not display significant gray matter BBB breakdown. Microhemorrhages were observed in one Ldlr\(^{-/-}\) mouse that was 6 months old. Results did not differ when considering subcortical and cortical regions. Conclusions In Ldlr\(^{-/-}\) mice, hypercholesterolemia is related to a thrombotic CSVD phenotype, which is different from hypertension-related CSVD that associates with a hemorrhagic CSVD phenotype. Our data demonstrate a relationship between hypercholesterolemia and the development of CSVD. Ldlr\(^{-/-}\) mice appear to be an adequate animal model for research into CSVD.}, 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{HoppNolteStetteretal.2017, author = {Hopp, Sarah and Nolte, Marc W. and Stetter, Christian and Kleinschnitz, Christoph and Sir{\´e}n, Anna-Leena and Albert-Weissenberger, Christiane}, title = {Alleviation of secondary brain injury, posttraumatic inflammation, and brain edema formation by inhibition of factor XIIa}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {39}, doi = {10.1186/s12974-017-0815-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157490}, year = {2017}, abstract = {Background: Traumatic brain injury (TBI) is a devastating neurological condition and a frequent cause of permanent disability. Posttraumatic inflammation and brain edema formation, two pathological key events contributing to secondary brain injury, are mediated by the contact-kinin system. Activation of this pathway in the plasma is triggered by activated factor XII. Hence, we set out to study in detail the influence of activated factor XII on the abovementioned pathophysiological features of TBI. Methods: Using a cortical cryogenic lesion model in mice, we investigated the impact of genetic deficiency of factor XII and inhibition of activated factor XII with a single bolus injection of recombinant human albumin-fused Infestin-4 on the release of bradykinin, the brain lesion size, and contact-kinin system-dependent pathological events. We determined protein levels of bradykinin, intracellular adhesion molecule-1, CC-chemokine ligand 2, and interleukin-1β by enzyme-linked immunosorbent assays and mRNA levels of genes related to inflammation by quantitative real-time PCR. Brain lesion size was determined by tetrazolium chloride staining. Furthermore, protein levels of the tight junction protein occludin, integrity of the blood-brain barrier, and brain water content were assessed by Western blot analysis, extravasated Evans Blue dye, and the wet weight-dry weight method, respectively. Infiltration of neutrophils and microglia/activated macrophages into the injured brain lesions was quantified by immunohistological stainings. Results: We show that both genetic deficiency of factor XII and inhibition of activated factor XII in mice diminish brain injury-induced bradykinin release by the contact-kinin system and minimize brain lesion size, blood-brain barrier leakage, brain edema formation, and inflammation in our brain injury model. Conclusions: Stimulation of bradykinin release by activated factor XII probably plays a prominent role in expanding secondary brain damage by promoting brain edema formation and inflammation. Pharmacological blocking of activated factor XII could be a useful therapeutic principle in the treatment of TBI-associated pathologic processes by alleviating posttraumatic inflammation and brain edema formation.}, language = {en} } @article{BailNotzRovitusoetal.2017, author = {Bail, Kathrin and Notz, Quirin and Rovituso, Damiano M. and Schampel, Andrea and Wunsch, Marie and Koeniger, Tobias and Schropp, Verena and Bharti, Richa and Scholz, Claus-Juergen and Foerstner, Konrad U. and Kleinschnitz, Christoph and Kuerten, Stefanie}, title = {Differential effects of FTY720 on the B cell compartment in a mouse model of multiple sclerosis.}, series = {Journal of Neuroinflammation}, volume = {14}, journal = {Journal of Neuroinflammation}, number = {148}, doi = {10.1186/s12974-017-0924-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157869}, year = {2017}, abstract = {Background: MP4-induced experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis (MS), which enables targeted research on B cells, currently much discussed protagonists in MS pathogenesis. Here, we used this model to study the impact of the S1P1 receptor modulator FTY720 (fingolimod) on the autoreactive B cell and antibody response both in the periphery and the central nervous system (CNS). Methods: MP4-immunized mice were treated orally with FTY720 for 30 days at the peak of disease or 50 days after EAE onset. The subsequent disease course was monitored and the MP4-specific B cell/antibody response was measured by ELISPOT and ELISA. RNA sequencing was performed to determine any effects on B cell-relevant gene expression. S1P\(_{1}\) receptor expression by peripheral T and B cells, B cell subset distribution in the spleen and B cell infiltration into the CNS were studied by flow cytometry. The formation of B cell aggregates and of tertiary lymphoid organs (TLOs) was evaluated by histology and immunohistochemistry. Potential direct effects of FTY720 on B cell aggregation were studied in vitro. Results: FTY720 significantly attenuated clinical EAE when treatment was initiated at the peak of EAE. While there was a significant reduction in the number of T cells in the blood after FTY720 treatment, B cells were only slightly diminished. Yet, there was evidence for the modulation of B cell receptor-mediated signaling upon FTY720 treatment. In addition, we detected a significant increase in the percentage of B220\(^{+}\) B cells in the spleen both in acute and chronic EAE. Whereas acute treatment completely abrogated B cell aggregate formation in the CNS, the numbers of infiltrating B cells and plasma cells were comparable between vehicle- and FTY720-treated mice. In addition, there was no effect on already developed aggregates in chronic EAE. In vitro B cell aggregation assays suggested the absence of a direct effect of FTY720 on B cell aggregation. However, FTY720 impacted the evolution of B cell aggregates into TLOs. Conclusions: The data suggest differential effects of FTY720 on the B cell compartment in MP4-induced EAE.}, language = {en} }