@article{FeldheimKesslerFeldheimetal.2022, author = {Feldheim, Jonas and Kessler, Almuth F. and Feldheim, Julia J. and Schulz, Ellina and Wend, David and Lazaridis, Lazaros and Kleinschnitz, Christoph and Glas, Martin and Ernestus, Ralf-Ingo and Brandner, Sebastian and Monoranu, Camelia M. and L{\"o}hr, Mario and Hagemann, Carsten}, title = {Effects of long-term temozolomide treatment on glioblastoma and astrocytoma WHO grade 4 stem-like cells}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {9}, issn = {1422-0067}, doi = {10.3390/ijms23095238}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284417}, year = {2022}, abstract = {Glioblastoma leads to a fatal course within two years in more than two thirds of patients. An essential cornerstone of therapy is chemotherapy with temozolomide (TMZ). The effect of TMZ is counteracted by the cellular repair enzyme O\(^6\)-methylguanine-DNA methyltransferase (MGMT). The MGMT promoter methylation, the main regulator of MGMT expression, can change from primary tumor to recurrence, and TMZ may play a significant role in this process. To identify the potential mechanisms involved, three primary stem-like cell lines (one astrocytoma with the mutation of the isocitrate dehydrogenase (IDH), CNS WHO grade 4 (HGA)), and two glioblastoma (IDH-wildtype, CNS WHO grade 4) were treated with TMZ. The MGMT promoter methylation, migration, proliferation, and TMZ-response of the tumor cells were examined at different time points. The strong effects of TMZ treatment on the MGMT methylated cells were observed. Furthermore, TMZ led to a loss of the MGMT promoter hypermethylation and induced migratory rather than proliferative behavior. Cells with the unmethylated MGMT promoter showed more aggressive behavior after treatment, while HGA cells reacted heterogenously. Our study provides further evidence to consider the potential adverse effects of TMZ chemotherapy and a rationale for investigating potential relationships between TMZ treatment and change in the MGMT promoter methylation during relapse.}, 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{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{FeldheimWendLaueretal.2022, author = {Feldheim, Jonas and Wend, David and Lauer, Mara J. and Monoranu, Camelia M. and Glas, Martin and Kleinschnitz, Christoph and Ernestus, Ralf-Ingo and Braunger, Barbara M. and Meybohm, Patrick and Hagemann, Carsten and Burek, Malgorzata}, title = {Protocadherin Gamma C3 (PCDHGC3) is strongly expressed in glioblastoma and its high expression is associated with longer progression-free survival of patients}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {15}, issn = {1422-0067}, doi = {10.3390/ijms23158101}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284433}, year = {2022}, abstract = {Protocadherins (PCDHs) belong to the cadherin superfamily and represent the largest subgroup of calcium-dependent adhesion molecules. In the genome, most PCDHs are arranged in three clusters, α, β, and γ on chromosome 5q31. PCDHs are highly expressed in the central nervous system (CNS). Several PCDHs have tumor suppressor functions, but their individual role in primary brain tumors has not yet been elucidated. Here, we examined the mRNA expression of PCDHGC3, a member of the PCDHγ cluster, in non-cancerous brain tissue and in gliomas of different World Health Organization (WHO) grades and correlated it with the clinical data of the patients. We generated a PCDHGC3 knockout U343 cell line and examined its growth rate and migration in a wound healing assay. We showed that PCDHGC3 mRNA and protein were significantly overexpressed in glioma tissue compared to a non-cancerous brain specimen. This could be confirmed in glioma cell lines. High PCDHGC3 mRNA expression correlated with longer progression-free survival (PFS) in glioma patients. PCDHGC3 knockout in U343 resulted in a slower growth rate but a significantly faster migration rate in the wound healing assay and decreased the expression of several genes involved in WNT signaling. PCDHGC3 expression should therefore be further investigated as a PFS-marker in gliomas. However, more studies are needed to elucidate the molecular mechanisms underlying the PCDHGC3 effects.}, language = {en} } @article{StetterLopezCaperuchipiHoppKraemeretal.2021, author = {Stetter, Christian and Lopez-Caperuchipi, Simon and Hopp-Kr{\"a}mer, Sarah and Bieber, Michael and Kleinschnitz, Christoph and Sir{\´e}n, Anna-Leena and Albert-Weißenberger, Christiane}, title = {Amelioration of cognitive and behavioral deficits after traumatic brain injury in coagulation factor XII deficient mice}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {9}, issn = {1422-0067}, doi = {10.3390/ijms22094855}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284959}, year = {2021}, abstract = {Based on recent findings that show that depletion of factor XII (FXII) leads to better posttraumatic neurological recovery, we studied the effect of FXII-deficiency on post-traumatic cognitive and behavioral outcomes in female and male mice. In agreement with our previous findings, neurological deficits on day 7 after weight-drop traumatic brain injury (TBI) were significantly reduced in FXII\(^{-/-}\) mice compared to wild type (WT) mice. Also, glycoprotein Ib (GPIb)-positive platelet aggregates were more frequent in brain microvasculature of WT than FXII\(^{-/-}\) mice 3 months after TBI. Six weeks after TBI, memory for novel object was significantly reduced in both female and male WT but not in FXII\(^{-/-}\) mice compared to sham-operated mice. In the setting of automated home-cage monitoring of socially housed mice in IntelliCages, female WT mice but not FXII\(^{-/-}\) mice showed decreased exploration and reacted negatively to reward extinction one month after TBI. Since neuroendocrine stress after TBI might contribute to trauma-induced cognitive dysfunction and negative emotional contrast reactions, we measured peripheral corticosterone levels and the ration of heart, lung, and spleen weight to bodyweight. Three months after TBI, plasma corticosterone levels were significantly suppressed in both female and male WT but not in FXII\(^{-/-}\) mice, while the relative heart weight increased in males but not in females of both phenotypes when compared to sham-operated mice. Our results indicate that FXII deficiency is associated with efficient post-traumatic behavioral and neuroendocrine recovery.}, language = {en} } @article{KoenigerBellMifkaetal.2021, author = {Koeniger, Tobias and Bell, Luisa and Mifka, Anika and Enders, Michael and Hautmann, Valentin and Mekala, Subba Rao and Kirchner, Philipp and Ekici, Arif B. and Schulz, Christian and W{\"o}rsd{\"o}rfer, Philipp and Mencl, Stine and Kleinschnitz, Christoph and Erg{\"u}n, S{\"u}leyman and Kuerten, Stefanie}, title = {Bone marrow-derived myeloid progenitors in the leptomeninges of adult mice}, series = {Stem Cells}, volume = {39}, journal = {Stem Cells}, number = {2}, doi = {10.1002/stem.3311}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224452}, pages = {227 -- 239}, year = {2021}, abstract = {Although the bone marrow contains most hematopoietic activity during adulthood, hematopoietic stem and progenitor cells can be recovered from various extramedullary sites. Cells with hematopoietic progenitor properties have even been reported in the adult brain under steady-state conditions, but their nature and localization remain insufficiently defined. Here, we describe a heterogeneous population of myeloid progenitors in the leptomeninges of adult C57BL/6 mice. This cell pool included common myeloid, granulocyte/macrophage, and megakaryocyte/erythrocyte progenitors. Accordingly, it gave rise to all major myelo-erythroid lineages in clonogenic culture assays. Brain-associated progenitors persisted after tissue perfusion and were partially inaccessible to intravenous antibodies, suggesting their localization behind continuous blood vessel endothelium such as the blood-arachnoid barrier. Flt3\(^{Cre}\) lineage tracing and bone marrow transplantation showed that the precursors were derived from adult hematopoietic stem cells and were most likely continuously replaced via cell trafficking. Importantly, their occurrence was tied to the immunologic state of the central nervous system (CNS) and was diminished in the context of neuroinflammation and ischemic stroke. Our findings confirm the presence of myeloid progenitors at the meningeal border of the brain and lay the foundation to unravel their possible functions in CNS surveillance and local immune cell production.}, language = {en} } @article{HeuschmannMontellanoUngethuemetal.2021, author = {Heuschmann, Peter U. and Montellano, Felipe A. and Ungeth{\"u}m, Kathrin and R{\"u}cker, Viktoria and Wiedmann, Silke and Mackenrodt, Daniel and Quilitzsch, Anika and Ludwig, Timo and Kraft, Peter and Albert, Judith and Morbach, Caroline and Frantz, Stefan and St{\"o}rk, Stefan and Haeusler, Karl Georg and Kleinschnitz, Christoph}, title = {Prevalence and determinants of systolic and diastolic cardiac dysfunction and heart failure in acute ischemic stroke patients: The SICFAIL study}, series = {ESC Heart Failure}, volume = {8}, journal = {ESC Heart Failure}, number = {2}, doi = {10.1002/ehf2.13145}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225656}, pages = {1117-1129}, year = {2021}, abstract = {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.}, language = {en} } @article{SimonIpekHomolaetal.2018, author = {Simon, Micha and Ipek, Rojda and Homola, Gy{\"o}rgy A. and Rovituso, Damiano M. and Schampel, Andrea and Kleinschnitz, Christoph and Kuerten, Stefanie}, title = {Anti-CD52 antibody treatment depletes B cell aggregates in the central nervous system in a mouse model of multiple sclerosis}, series = {Journal of Neuroinflammation}, volume = {15}, journal = {Journal of Neuroinflammation}, number = {225}, doi = {10.1186/s12974-018-1263-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176120}, year = {2018}, abstract = {Background: Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) for which several new treatment options were recently introduced. Among them is the monoclonal anti-CD52 antibody alemtuzumab that depletes mainly B cells and T cells in the immune periphery. Considering the ongoing controversy about the involvement of B cells and in particular the formation of B cell aggregates in the brains of progressive MS patients, an in-depth understanding of the effects of anti-CD52 antibody treatment on the B cell compartment in the CNS itself is desirable. Methods: We used myelin basic protein (MBP)-proteolipid protein (PLP)-induced experimental autoimmune encephalomyelitis (EAE) in C57BL/6 (B6) mice as B cell-dependent model of MS. Mice were treated intraperitoneally either at the peak of EAE or at 60 days after onset with 200 μg murine anti-CD52 vs. IgG2a isotype control antibody for five consecutive days. Disease was subsequently monitored for 10 days. The antigen-specific B cell/antibody response was measured by ELISPOT and ELISA. Effects on CNS infiltration and B cell aggregation were determined by immunohistochemistry. Neurodegeneration was evaluated by Luxol Fast Blue, SMI-32, and Olig2/APC staining as well as by electron microscopy and phosphorylated heavy neurofilament serum ELISA. Results: Treatment with anti-CD52 antibody attenuated EAE only when administered at the peak of disease. While there was no effect on the production of MP4-specific IgG, the treatment almost completely depleted CNS infiltrates and B cell aggregates even when given as late as 60 days after onset. On the ultrastructural level, we observed significantly less axonal damage in the spinal cord and cerebellum in chronic EAE after anti-CD52 treatment. Conclusion: Anti-CD52 treatment abrogated B cell infiltration and disrupted existing B cell aggregates in the CNS.}, 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{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{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{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} } @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{RovitusoSchefflerWunschetal.2016, author = {Rovituso, Damiano M. and Scheffler, Laura and Wunsch, Marie and Kleinschnitz, Christoph and D{\"o}rck, Sebastian and Ulzheimer, Jochen and Bayas, Antonios and Steinman, Lawrence and Erg{\"u}n, S{\"u}leyman and Kuerten, Stefanie}, title = {CEACAM1 mediates B cell aggregation in central nervous system autoimmunity}, series = {Scientific Reports}, volume = {6}, journal = {Scientific Reports}, doi = {10.1038/srep29847}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147690}, pages = {29847}, year = {2016}, abstract = {B cell aggregates in the central nervous system (CNS) have been associated with rapid disease progression in patients with multiple sclerosis (MS). Here we demonstrate a key role of carcinoembryogenic antigen-related cell adhesion molecule1 (CEACAM1) in B cell aggregate formation in MS patients and a B cell-dependent mouse model of MS. CEACAM1 expression was increased on peripheral blood B cells and CEACAM1\(^+\) B cells were present in brain infiltrates of MS patients. Administration of the anti-CEACAM1 antibody T84.1 was efficient in blocking aggregation of B cells derived from MS patients. Along these lines, application of the monoclonal anti-CEACAM1 antibody mCC1 was able to inhibit CNS B cell aggregate formation and significantly attenuated established MS-like disease in mice in the absence of any adverse effects. CEACAM1 was co-expressed with the regulator molecule T cell immunoglobulin and mucin domain -3 (TIM-3) on B cells, a novel molecule that has recently been described to induce anergy in T cells. Interestingly, elevated coexpression on B cells coincided with an autoreactive T helper cell phenotype in MS patients. Overall, these data identify CEACAM1 as a clinically highly interesting target in MS pathogenesis and open new therapeutic avenues for the treatment of the disease.}, language = {en} } @article{HoppAlbertWeissenbergerMencletal.2016, author = {Hopp, Sarah and Albert-Weissenberger, Christiane and Mencl, Stine and Bieber, Michael and Schuhmann, Michael K. and Stetter, Christian and Nieswandt, Bernhard and Schmidt, Peter M. and Monoranu, Camelia-Maria and Alafuzoff, Irina and Marklund, Niklas and Nolte, Marc W. and Sir{\´e}n, Anna-Leena and Kleinschnitz, Christoph}, title = {Targeting coagulation factor XII as a novel therapeutic option in brain trauma}, series = {Annals of Neurology}, volume = {79}, journal = {Annals of Neurology}, number = {6}, doi = {10.1002/ana.24655}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188800}, pages = {970-982}, year = {2016}, abstract = {Objective: Traumatic brain injury is a major global public health problem for which specific therapeutic interventions are lacking. There is, therefore, a pressing need to identify innovative pathomechanism-based effective therapies for this condition. Thrombus formation in the cerebral microcirculation has been proposed to contribute to secondary brain damage by causing pericontusional ischemia, but previous studies have failed to harness this finding for therapeutic use. The aim of this study was to obtain preclinical evidence supporting the hypothesis that targeting factor XII prevents thrombus formation and has a beneficial effect on outcome after traumatic brain injury. Methods: We investigated the impact of genetic deficiency of factor XII and acute inhibition of activated factor XII with a single bolus injection of recombinant human albumin-fused infestin-4 (rHA-Infestin-4) on trauma-induced microvascular thrombus formation and the subsequent outcome in 2 mouse models of traumatic brain injury. Results: Our study showed that both genetic deficiency of factor XII and an inhibition of activated factor XII in mice minimize trauma-induced microvascular thrombus formation and improve outcome, as reflected by better motor function, reduced brain lesion volume, and diminished neurodegeneration. Administration of human factor XII in factor XII-deficient mice fully restored injury-induced microvascular thrombus formation and brain damage. Interpretation: The robust protective effect of rHA-Infestin-4 points to a novel treatment option that can decrease ischemic injury after traumatic brain injury without increasing bleeding tendencies.}, language = {en} } @article{KornKleinschnitzMagnusetal.2016, author = {Korn, Thomas and Kleinschnitz, Christoph and Magnus, Tim and Meuth, Sven G. and Linker, Ralf A.}, title = {Report on the 7th scientific meeting of the Association for the Advancement of Young Academics in Neurology (NEUROWIND e.V.) held in Motzen, Germany, October 30-November 1, 2015}, series = {Experimental and Translational Stroke Medicine}, volume = {8}, journal = {Experimental and Translational Stroke Medicine}, number = {3}, organization = {7th NEUROWIND e.V. scientific meeting}, doi = {10.1186/s13231-016-0017-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146595}, year = {2016}, abstract = {From October 30-November 1, 2015, the 7th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. Seventy doctoral students and postdocs from over 25 different groups working in German and Swiss University Hospitals or Research Institutes attended the meeting to discuss their latest experiments and findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. This meeting report summarizes the many diverse presentations and the new preclinical to clinical neurology research data that were shared by the participants at the meeting.}, language = {en} } @article{IsraelOhsiekAlMomanietal.2016, author = {Israel, Ina and Ohsiek, Andrea and Al-Momani, Ehab and Albert-Weissenberger, Christiane and Stetter, Christian and Mencl, Stine and Buck, Andreas K. and Kleinschnitz, Christoph and Samnick, Samuel and Sir{\´e}n, Anna-Leena}, title = {Combined [\(^{18}\)F]DPA-714 micro-positron emission tomography and autoradiography imaging of microglia activation after closed head injury in mice}, series = {Journal of Neuroinflammation}, volume = {13}, journal = {Journal of Neuroinflammation}, number = {140}, doi = {10.1186/s12974-016-0604-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146606}, year = {2016}, abstract = {Background Traumatic brain injury (TBI) is a major cause of death and disability. Neuroinflammation contributes to acute damage after TBI and modulates long-term evolution of degenerative and regenerative responses to injury. The aim of the present study was to evaluate the relationship of microglia activation to trauma severity, brain energy metabolism, and cellular reactions to injury in a mouse closed head injury model using combined in vivo PET imaging, ex vivo autoradiography, and immunohistochemistry. Methods A weight-drop closed head injury model was used to produce a mixed diffuse and focal TBI or a purely diffuse mild TBI (mTBI) in C57BL6 mice. Lesion severity was determined by evaluating histological damage and functional outcome using a standardized neuroscore (NSS), gliosis, and axonal injury by immunohistochemistry. Repeated intra-individual in vivo μPET imaging with the specific 18-kDa translocator protein (TSPO) radioligand [\(^{18}\)F]DPA-714 was performed on day 1, 7, and 16 and [\(^{18}\)F]FDG-μPET imaging for energy metabolism on days 2-5 after trauma using freshly synthesized radiotracers. Immediately after [\(^{18}\)F]DPA-714-μPET imaging on days 7 and 16, cellular identity of the [\(^{18}\)F]DPA-714 uptake was confirmed by exposing freshly cut cryosections to film autoradiography and successive immunostaining with antibodies against the microglia/macrophage marker IBA-1. Results Functional outcome correlated with focal brain lesions, gliosis, and axonal injury. [\(^{18}\)F]DPA-714-μPET showed increased radiotracer uptake in focal brain lesions on days 7 and 16 after TBI and correlated with reduced cerebral [\(^{18}\)F]FDG uptake on days 2-5, with functional outcome and number of IBA-1 positive cells on day 7. In autoradiography, [\(^{18}\)F]DPA-714 uptake co-localized with areas of IBA1-positive staining and correlated strongly with both NSS and the number of IBA1-positive cells, gliosis, and axonal injury. After mTBI, numbers of IBA-1 positive cells with microglial morphology increased in both brain hemispheres; however, uptake of [\(^{18}\)F]DPA-714 was not increased in autoradiography or in μPET imaging. Conclusions [\(^{18}\)F]DPA-714 uptake in μPET/autoradiography correlates with trauma severity, brain metabolic deficits, and microglia activation after closed head TBI.}, language = {en} } @article{GoebelPankratzAsaridouetal.2016, author = {G{\"o}bel, Kerstin and Pankratz, Susann and Asaridou, Chloi-Magdalini and Herrmann, Alexander M. and Bittner, Stefan and Merker, Monika and Ruck, Tobias and Glumm, Sarah and Langhauser, Friederike and Kraft, Peter and Krug, Thorsten F. and Breuer, Johanna and Herold, Martin and Gross, Catharina C. and Beckmann, Denise and Korb-Pap, Adelheid and Schuhmann, Michael K. and Kuerten, Stefanie and Mitroulis, Ioannis and Ruppert, Clemens and Nolte, Marc W. and Panousis, Con and Klotz, Luisa and Kehrel, Beate and Korn, Thomas and Langer, Harald F. and Pap, Thomas and Nieswandt, Bernhard and Wiendl, Heinz and Chavakis, Triantafyllos and Kleinschnitz, Christoph and Meuth, Sven G.}, title = {Blood coagulation factor XII drives adaptive immunity during neuroinflammation via CD87-mediated modulation of dendritic cells}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, number = {11626}, doi = {10.1038/ncomms11626}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165503}, year = {2016}, abstract = {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.}, 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{KleinschnitzNiemczykRehbergWeberetal.2015, author = {Kleinschnitz, Christoph and Niemczyk, Gabriele and Rehberg-Weber, Karin and Wernsd{\"o}rfer, Colin}, title = {Interferon Beta-1a (AVONEX®) as a treatment option for untreated patients with multiple sclerosis (AXIOM): a prospective, observational study}, series = {International Journal of Molecular Sciences}, volume = {16}, journal = {International Journal of Molecular Sciences}, doi = {10.3390/ijms160715271}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148487}, pages = {15271-15286}, year = {2015}, abstract = {The efficacy and safety of first-line disease-modifying therapies (DMT) for relapsing-remitting multiple sclerosis (RRMS) has been demonstrated in pivotal, randomized trials, but these studies do not reflect the routine care setting where treatment gaps or switches are common. The Avonex as Treatment Option for Untreated MS Patients (AXIOM) trial assessed the efficacy of newly-initiated intramuscular interferon beta-1a (IM IFNb-1a) after a treatment-free interval, with particular consideration of the previous course of disease and therapy. The AXIOM trial was an open, 12-month, observational, non-interventional study with a retrospective and a prospective part conducted in Germany. RRMS patients with a treatment-free interval of at least three months were included and treated with IFNb-1a for up to 12 months. Relapse rate, disability progression, injection-related parameters and quality of life observed during the prospective part were compared with retrospectively-collected data. Two hundred and thirty five RRMS patients participated in AXIOM. The mean relapse rate decreased from 1.1 in the three months before baseline to 0.2 per quarter during the twelve-month observational period; the Multiple Sclerosis Functional Composite score improved during twelve months of IM IFNb-1a treatment, while the Expanded Disability Status Scale score did not change over the course of this study. Compared to previous DMTs (IM IFNb-1a, subcutaneous IFNb-1a (SC IFNb-1a), SC IFNb-1b, glatiramer acetate), the patients experienced less injection site reactions and flu-like symptoms, with a stated improved quality of life. IM IFNb-1a was effective and well accepted in RRMS patients with no or discontinued previous therapy. These results from the routine care setting may inform optimization of DMT treatment in RRMS, but need confirmation in further studies.}, language = {en} } @article{FluriSchuhmannKleinschnitz2015, author = {Fluri, Felix and Schuhmann, Michael K and Kleinschnitz, Christoph}, title = {Animal models of ischemic stroke and their application in clinical research}, series = {Drug Design, Development and Therapy}, volume = {9}, journal = {Drug Design, Development and Therapy}, doi = {10.2147/DDDT.S56071}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149157}, pages = {3445-3454}, year = {2015}, abstract = {This review outlines the most frequently used rodent stroke models and discusses their strengths and shortcomings. Mimicking all aspects of human stroke in one animal model is not feasible because ischemic stroke in humans is a heterogeneous disorder with a complex pathophysiology. The transient or permanent middle cerebral artery occlusion (MCAo) model is one of the models that most closely simulate human ischemic stroke. Furthermore, this model is characterized by reliable and well-reproducible infarcts. Therefore, the MCAo model has been involved in the majority of studies that address pathophysiological processes or neuroprotective agents. Another model uses thromboembolic clots and thus is more convenient for investigating thrombolytic agents and pathophysiological processes after thrombolysis. However, for many reasons, preclinical stroke research has a low translational success rate. One factor might be the choice of stroke model. Whereas the therapeutic responsiveness of permanent focal stroke in humans declines significantly within 3 hours after stroke onset, the therapeutic window in animal models with prompt reperfusion is up to 12 hours, resulting in a much longer action time of the investigated agent. Another major problem of animal stroke models is that studies are mostly conducted in young animals without any comorbidity. These models differ from human stroke, which particularly affects elderly people who have various cerebrovascular risk factors. Choosing the most appropriate stroke model and optimizing the study design of preclinical trials might increase the translational potential of animal stroke models.}, language = {en} } @article{LugerHohmannNiemannetal.2015, author = {Luger, Sebastian and Hohmann, Carina and Niemann, Daniela and Kraft, Peter and Gunreben, Ignaz and Neumann-Haefelin, Tobias and Kleinschnitz, Christoph and Steinmetz, Helmuth and Foerch, Christian and Pfeilschifter, Waltraud}, title = {Adherence to oral anticoagulant therapy in secondary stroke prevention - impact of the novel oral anticoagulants}, series = {Patient Preference and Adherence}, volume = {9}, journal = {Patient Preference and Adherence}, doi = {10.2147/PPA.S88994}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-144477}, pages = {1695-1705}, year = {2015}, abstract = {Background: Oral anticoagulant therapy (OAT) potently prevents strokes in patients with atrial fibrillation. Vitamin K antagonists (VKA) have been the standard of care for long-term OAT for decades, but non-VKA oral anticoagulants (NOAC) have recently been approved for this indication, and raised many questions, among them their influence on medication adherence. We assessed adherence to VKA and NOAC in secondary stroke prevention. Methods: All patients treated from October 2011 to September 2012 for ischemic stroke or transient ischemic attack with a subsequent indication for OAT, at three academic hospitals were entered into a prospective registry, and baseline data and antithrombotic treatment at discharge were recorded. At the 1-year follow-up, we assessed the adherence to different OAT strategies and patients' adherence to their respective OAT. We noted OAT changes, reasons to change treatment, and factors that influence persistence to the prescribed OAT. Results: In patients discharged on OAT, we achieved a fatality corrected response rate of 73.3\% (n=209). A total of 92\% of these patients received OAT at the 1-year follow-up. We observed good adherence to both VKA and NOAC (VKA, 80.9\%; NOAC, 74.8\%; P=0.243) with a statistically nonsignificant tendency toward a weaker adherence to dabigatran. Disability at 1-year follow-up was an independent predictor of lower adherence to any OAT after multivariate analysis, whereas the choice of OAT did not have a relevant influence. Conclusion: One-year adherence to OAT after stroke is strong (>90\%) and patients who switch therapy most commonly switch toward another OAT. The 1-year adherence rates to VKA and NOAC in secondary stroke prevention do not differ significantly between both therapeutic strategies.}, 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{FluriFleischerKleinschnitz2015, author = {Fluri, Felix and Fleischer, Michael and Kleinschnitz, Christoph}, title = {Accidental Thrombolysis in a Stroke Patient Receiving Apixaban}, series = {Cerebrovascular Diseases Extra}, volume = {5}, journal = {Cerebrovascular Diseases Extra}, doi = {10.1159/000375181}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126326}, pages = {55-56}, year = {2015}, abstract = {No abstract available.}, language = {en} } @article{KleinschnitzLinkerMagnusetal.2015, author = {Kleinschnitz, Christoph and Linker, Ralf A. and Magnus, Tim and Korn, Thomas and Meuth, Sven G.}, title = {Report on the 6th scientific meeting of the "Verein zur F{\"o}rderung des Wissenschaftlichen Nachwuchses in der Neurologie" (NEUROWIND e.V.) held in Motzen, Germany, Oct. 31th - Nov. 2nd, 2014}, series = {Experimental \& Translational Stroke Medicine}, volume = {7}, journal = {Experimental \& Translational Stroke Medicine}, number = {1}, organization = {on behalf of the speakers at the 6'th NEUROWIND e.V. scientific meeting}, doi = {10.1186/s13231-014-0013-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125049}, year = {2015}, abstract = {From October 31th - November 2nd, 2014, the 6th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. 70 doctoral students and postdocs from over 25 different groups working in German and Swiss university hospitals or research institutes attended the meeting to discuss their latest experiments and findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. The meeting was regarded as a very well organized platform to support research of young investigators in Germany and all participants enjoyed the stimulating environment for lively in depth discussions. According to the major aim of NEUROWIND e.V. to support younger researchers in Germany the 4th NEUROWIND YOUNG SCIENTIST AWARD for experimental neurology was awarded to Michael Breckwoldt on his work in the group of Thomas Misgeld (Institute of Neuronal Cell Biology, Technische Universit{\"a}t M{\"u}nchen, Germany). The successful project was published in Nature Medicine entitled "Multiparametric optical analysis of mitochondrial redox signals during neuronal physiology and pathology in vivo". This outstanding paper deals with a molecular imaging approach in living mice to optically analyze the role of mitochondrial redox signals in axons in health and disease. The award is endowed with 20.000 Euro sponsored by Merck Serono GmbH, Darmstadt, Germany (unrestricted educational grant). This year's keynote lecture was given by Bernhard Hemmer, Head of the Department of Neurology at the Klinikum rechts der Isar, Technische Universit{\"a}t M{\"u}nchen. Dr. Hemmer highlighted the particular role of B cells and (auto)antibodies in multiple sclerosis (MS). As a new highlight Dr. Urbahns, head of global discovery technologies at Merck research laboratories, gave insights from research practice in the pharmaceutical industry and introduced a shift in the view on present-day drug discovery paradigms.}, language = {en} } @article{RuckBittnerAfzalietal.2015, author = {Ruck, Tobias and Bittner, Stefan and Afzali, Ali Maisam and G{\"o}bel, Kerstin and Glumm, Sarah and Kraft, Peter and Sommer, Claudia and Kleinschnitz, Christoph and Preusse, Corinna and Stenzel, Werner and Wiendl, Heinz and Meuth, Sven G.}, title = {The NKG2D-IL-15 signaling pathway contributes to T-cell mediated pathology in inflammatory myopathies}, series = {Oncotarget}, volume = {6}, journal = {Oncotarget}, number = {41}, doi = {10.18632/oncotarget.6462}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136047}, year = {2015}, abstract = {NKG2D is an activating receptor on T cells, which has been implicated in the pathogenesis of autoimmune diseases. T cells are critically involved in idiopathic inflammatory myopathies (IIM) and have been proposed as specific therapeutic targets. However, the mechanisms underlying T cell-mediated progressive muscle destruction in IIM remain to be elucidated. We here determined the involvement of the NKG2D - IL-15 signaling pathway. Primary human myoblasts expressed NKG2D ligands, which were further upregulated upon inflammatory stimuli. In parallel, shedding of the soluble NKG2D ligand MICA (sMICA) decreased upon inflammation potentially diminishing inhibition of NKG2D signaling. Membrane-related expression of IL-15 by myoblasts induced differentiation of naive CD8\(^+\) T cells into highly activated, cytotoxic \(CD8^+NKG2D^{high}\) T cells demonstrating NKG2D-dependent lysis of myoblasts in vitro. \(CD8^+NKG2D^{high}\) T cell frequencies were increased in the peripheral blood of polymyositis (PM) patients and correlated with serum creatinine kinase concentrations, while serum sMICA levels were not significantly changed. In muscle biopsy specimens from PM patients expression of the NKG2D ligand MICA/B was upregulated, IL-15 was expressed by muscle cells, CD68\(^+\) macrophages as well as CD4\(^+\) T cells, and \(CD8^+NKG2D^+\) cells were frequently detected within inflammatory infiltrates arguing for a local signaling circuit in the inflammatory muscle milieu. In conclusion, the NKG2D - IL-15 signaling pathway contributes to progressive muscle destruction in IIM potentially opening new therapeutic avenues.}, language = {en} } @article{RovitusoDuffySchroeteretal.2015, author = {Rovituso, Damiano M. and Duffy, Catharina E. and Schroeter, Michael and Kaiser, Claudia C. and Kleinschnitz, Christoph and Bayas, Antonios and Elsner, Rebecca and Kuerten, Stefanie}, title = {The brain antigen-specific B cell response correlates with glatiramer acetate responsiveness in relapsing-remitting multiple sclerosis patients}, series = {Scientific Reports}, volume = {5}, journal = {Scientific Reports}, number = {14265}, doi = {10.1038/srep14265}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148172}, year = {2015}, abstract = {B cells have only recently begun to attract attention in the immunopathology of multiple sclerosis (MS). Suitable markers for the prediction of treatment success with immunomodulatory drugs are still missing. Here we evaluated the B cell response to brain antigens in n = 34 relapsing-remitting MS (RRMS) patients treated with glatiramer acetate (GA) using the enzyme-linked immunospot technique (ELISPOT). Our data demonstrate that patients can be subdivided into responders that show brain-specific B cell reactivity in the blood and patients without this reactivity. Only in patients that classified as B cell responders, there was a significant positive correlation between treatment duration and the time since last relapse in our study. This correlation was GA-specific because it was absent in a control group that consisted of interferon-\(\beta\) (IFN-\(\beta\))-treated RRMS patients (n = 23). These data suggest that GA has an effect on brain-reactive B cells in a subset of patients and that only this subset benefits from treatment. The detection of brain-reactive B cells is likely to be a suitable tool to identify drug responders.}, language = {en} } @article{SchuhmannBittnerMeuthetal.2015, author = {Schuhmann, Michael K. and Bittner, Stefan and Meuth, Sven G. and Kleinschnitz, Christoph and Fluri, Felix}, title = {Fingolimod (FTY720-P) does not stabilize the blood-brain barrier under inflammatory conditions in an in vitro model}, series = {International Journal of Molecular Sciences}, volume = {16}, journal = {International Journal of Molecular Sciences}, doi = {10.3390/ijms161226177}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-145047}, pages = {29454-29466}, year = {2015}, abstract = {Breakdown of the blood-brain barrier (BBB) is an early hallmark of multiple sclerosis (MS), a progressive inflammatory disease of the central nervous system. Cell adhesion in the BBB is modulated by sphingosine-1-phosphate (S1P), a signaling protein, via S1P receptors (S1P\(_1\)). Fingolimod phosphate (FTY720-P) a functional S1P\(_1\) antagonist has been shown to improve the relapse rate in relapsing-remitting MS by preventing the egress of lymphocytes from lymph nodes. However, its role in modulating BBB permeabilityin particular, on the tight junction proteins occludin, claudin 5 and ZO-1has not been well elucidated to date. In the present study, FTY720-P did not change the transendothelial electrical resistance in a rat brain microvascular endothelial cell (RBMEC) culture exposed to inflammatory conditions and thus did not decrease endothelial barrier permeability. In contrast, occludin was reduced in RBMEC culture after adding FTY720-P. Additionally, FTY720-P did not alter the amount of endothelial matrix metalloproteinase (MMP)-9 and MMP-2 in RBMEC cultures. Taken together, our observations support the assumption that S1P\(_1\) plays a dual role in vascular permeability, depending on its ligand. Thus, S1P\(_1\) provides a mechanistic basis for FTY720-P-associated disruption of endothelial barrierssuch as the blood-retinal barrierwhich might result in macular edema.}, language = {en} } @article{KraftDrechslerGunrebenetal.2015, author = {Kraft, Peter and Drechsler, Christiane and Gunreben, Ignaz and Heuschmann, Peter Ulrich and Kleinschnitz, Christoph}, title = {Case-control study of platelet glycoprotein receptor Ib and IIb/IIIa expression in patients with acute and chronic cerebrovascular disease}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0119810}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148806}, pages = {e0119810}, year = {2015}, abstract = {Background Animal models have been instrumental in defining thrombus formation, including the role of platelet surface glycoprotein (GP) receptors, in acute ischemic stroke (AIS). However, the involvement of GP receptors in human ischemic stroke pathophysiology and their utility as biomarkers for ischemic stroke risk and severity requires elucidation. Aims To determine whether platelet GPIb and GPIIb/IIIa receptors are differentially expressed in patients with AIS and chronic cerebrovascular disease (CCD) compared with healthy volunteers (HV) and to identify predictors of GPIb and GPIIb/IIIa expression. Methods This was a case-control study of 116 patients with AIS or transient ischemic attack (TIA), 117 patients with CCD, and 104 HV who were enrolled at our University hospital from 2010 to 2013. Blood sampling was performed once in the CCD and HV groups, and at several time points in patients with AIS or TIA. Linear regression and analysis of variance were used to analyze correlations between platelet GPIb and GPIIb/IIIa receptor numbers and demographic and clinical parameters. Results GPIb and GPIIb/IIIa receptor numbers did not significantly differ between the AIS, CCD, and HV groups. GPIb receptor expression level correlated significantly with the magnitude of GPIIb/IIIa receptor expression and the neutrophil count. In contrast, GPIIb/IIIa receptor numbers were not associated with peripheral immune-cell sub-population counts. Creactive protein was an independent predictor of GPIIb/IIIa (not GPIb) receptor numbers. Conclusions Platelet GPIb and GPIIb/IIIa receptor numbers did not distinguish between patient or control groups in this study, negating their potential use as a biomarker for predicting stroke risk.}, language = {en} } @article{KleikersHooijmansGoebetal.2015, author = {Kleikers, Pamela W. M. and Hooijmans, Carlijn and G{\"o}b, Eva and Langhauser, Friederike and Rewell, Sarah S. J. and Radermacher, Kim and Ritskes-Hoitinga, Merel and Howells, David W. and Kleinschnitz, Christoph and Schmidt, Harald H. H. W.}, title = {A combined pre-clinical meta-analysis and randomized confirmatory trial approach to improve data validity for therapeutic target validation}, series = {Scientific Reports}, volume = {5}, journal = {Scientific Reports}, number = {13428}, doi = {10.1038/srep13428}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-151401}, year = {2015}, abstract = {Biomedical research suffers from a dramatically poor translational success. For example, in ischemic stroke, a condition with a high medical need, over a thousand experimental drug targets were unsuccessful. Here, we adopt methods from clinical research for a late-stage pre-clinical meta-analysis (MA) and randomized confirmatory trial (pRCT) approach. A profound body of literature suggests NOX\(_{2}\) to be a major therapeutic target in stroke. Systematic review and MA of all available NOX\(_{2}\)\(^{-/y}\) studies revealed a positive publication bias and lack of statistical power to detect a relevant reduction in infarct size. A fully powered multi-center pRCT rejects NOX\(_{2}\) as a target to improve neurofunctional outcomes or achieve a translationally relevant infarct size reduction. Thus stringent statistical thresholds, reporting negative data and a MA-pRCT approach can ensure biomedical data validity and overcome risks of bias.}, 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{AlbertWeissenbergerMenclSchuhmannetal.2014, author = {Albert-Weissenberger, Christiane and Mencl, Stine and Schuhmann, Michael K. and Salur, Irmak and G{\"o}b, Eva and Langhauser, Friederike and Hopp, Sarah and Hennig, Nelli and Meuth, Sven G. and Nolte, Marc W. and Sir{\´e}n, Anna-Leena and Kleinschnitz, Christoph}, title = {C1-Inhibitor protects from focal brain trauma in a cortical cryolesion mice model by reducing thrombo-inflammation}, series = {Frontiers in Cellular Neuroscience}, volume = {8}, journal = {Frontiers in Cellular Neuroscience}, issn = {1662-5102}, doi = {10.3389/fncel.2014.00269}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119263}, pages = {269}, year = {2014}, abstract = {Traumatic brain injury (TBI) induces a strong inflammatory response which includes blood-brain barrier damage, edema formation and infiltration of different immune cell subsets. More recently, microvascular thrombosis has been identified as another pathophysiological feature of TBI. The contact-kinin system represents an interface between inflammatory and thrombotic circuits and is activated in different neurological diseases. C1-Inhibitor counteracts activation of the contact-kinin system at multiple levels. We investigated the therapeutic potential of C1-Inhibitor in a model of TBI. Male and female C57BL/6 mice were subjected to cortical cryolesion and treated with C1-Inhibitor after 1 h. Lesion volumes were assessed between day 1 and day 5 and blood-brain barrier damage, thrombus formation as well as the local inflammatory response were determined post TBI. Treatment of male mice with 15.0 IU C1-Inhibitor, but not 7.5 IU, 1 h after cryolesion reduced lesion volumes by ~75\% on day 1. This protective effect was preserved in female mice and at later stages of trauma. Mechanistically, C1-Inhibitor stabilized the blood-brain barrier and decreased the invasion of immune cells into the brain parenchyma. Moreover, C1-Inhibitor had strong antithrombotic effects. C1-Inhibitor represents a multifaceted anti-inflammatory and antithrombotic compound that prevents traumatic neurodegeneration in clinically meaningful settings.}, language = {en} } @article{NiklassStoyanovGarzetal.2014, author = {Niklass, Solveig and Stoyanov, Stoyan and Garz, Cornelia and Bueche, Celine Z. and Mencl, Stine and Reymann, Klaus and Heinze, Hans-Jochen and Carare, Roxana O. and Kleinschnitz, Christoph and Schreiber, Stefanie}, title = {Intravital imaging in spontaneously hypertensive stroke-prone rats-a pilot study}, series = {Experimental \& Translational Stroke Medicine}, volume = {6}, journal = {Experimental \& Translational Stroke Medicine}, doi = {10.1186/2040-7378-6-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121353}, pages = {1}, year = {2014}, abstract = {Background There is growing evidence that endothelial failure and subsequent blood brain barrier (BBB) breakdown initiate cerebral small vessel disease (CSVD) pathology. In spontaneously hypertensive stroke-prone rats (SHRSP) endothelial damage is indicated by intraluminal accumulations of erythrocytes (erythrocyte thrombi) that are not observed with current magnetic resonance imaging techniques. Two-photon microscopy (2 PM) offers the potential for real-time direct detection of the small vasculature. Thus, within this pilot study we investigated the sensitivity of 2 PM to detect erythrocyte thrombi expressing initiating CSVD phenomena in vivo. Methods Eight SHRSP and 13 Wistar controls were used for in vivo imaging and subsequent histology with haematoxylin-eosin (HE). For 2 PM, cerebral blood vessels were labeled by fluorescent Dextran (70 kDa) applied intraorbitally. The correlation between vascular erythrocyte thrombi observed by 2 PM and HE-staining was assessed. Artificial surgical damage and parenchymal Dextran distribution were analyzed postmortem. Results Dextran was distributed within the small vessel walls and co-localized with IgG. Artificial surgical damage was comparable between SHRSP and Wistar controls and mainly affected the small vasculature. In fewer than 20\% of animals there was correlation between erythrocyte thrombi as observed with 2 PM and histologically with HE. Conclusions Contrary to our initial expectations, there was little agreement between intravital 2 PM imaging and histology for the detection of erythrocyte thrombi. Two-photon microscopy is a valuable technique that complements but does not replace the value of conventional histology.}, language = {en} } @article{HohnmannMillesSchinkeetal.2014, author = {Hohnmann, Christopher and Milles, Bianca and Schinke, Michael and Schroeter, Michael and Ulzheimer, Jochen and Kraft, Peter and Kleinschnitz, Christoph and Lehmann, Paul V. and Kuerten, Stefanie}, title = {Categorization of multiple sclerosis relapse subtypes by B cell profiling in the blood}, series = {Acta Neuropathologica Communications}, volume = {2}, journal = {Acta Neuropathologica Communications}, number = {138}, doi = {10.1186/s40478-014-0138-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126124}, year = {2014}, abstract = {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.}, language = {en} } @article{AlbertWeissenbergerMenclHoppetal.2014, author = {Albert-Weissenberger, Christiane and Mencl, Stine and Hopp, Sarah and Kleinschnitz, Christoph and Siren, Anna-Leena}, title = {Role of the kallikrein-kinin system in traumatic brain injury}, series = {Frontiers in Cellular Neuroscience}, volume = {8}, journal = {Frontiers in Cellular Neuroscience}, issn = {1662-5102}, doi = {10.3389/fncel.2014.00345}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-118226}, pages = {345}, year = {2014}, abstract = {Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Despite improvements in acute intensive care, there are currently no specific therapies to ameliorate the effects of TBI. Successful therapeutic strategies for TBI should target multiple pathophysiologic mechanisms that occur at different stages of brain injury. The kallikrein-kinin system is a promising therapeutic target for TBI as it mediates key pathologic events of traumatic brain damage, such as edema formation, inflammation, and thrombosis. Selective and specific kinin receptor antagonists and inhibitors of plasma kallikrein and coagulation factor XII have been developed, and have already shown therapeutic efficacy in animal models of stroke and TBI. However, conflicting preclinical evaluation, as well as limited and inconclusive data from clinical trials in TBI, suggests that caution should be taken before transferring observations made in animals to humans. This review summarizes current evidence on the pathologic significance of the kallikrein-kinin system during TBI in animal models and, where available, the experimental findings are compared with human data.}, language = {en} } @article{HohmannMillesSchinkeetal.2014, author = {Hohmann, Christopher and Milles, Bianca and Schinke, Michael and Schroeter, Michael and Ulzheimer, Jochen and Kraft, Peter and Kleinschnitz, Christoph and Lehmann, Paul V. and Kuerten, Stefanie}, title = {Categorization of multiple sclerosis relapse subtypes by B cell profiling in the blood}, series = {Acta Neuropathologica Communications}, volume = {2}, journal = {Acta Neuropathologica Communications}, number = {138}, issn = {2051-5960}, doi = {10.1186/s40478-014-0138-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120580}, year = {2014}, abstract = {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.}, 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{KleinschnitzGoebelMeuthetal.2014, author = {Kleinschnitz, Christoph and G{\"o}bel, Kerstin and Meuth, Sven G. and Kraft, Peter}, title = {Glatiramer acetate does not protect from acute ischemic stroke in mice}, doi = {10.1186/2040-7378-6-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-110528}, year = {2014}, abstract = {Background The role of the immune system in the pathophysiology of acute ischemic stroke is increasingly recognized. However, targeted treatment strategies to modulate immunological pathways in stroke are still lacking. Glatiramer acetate is a multifaceted immunomodulator approved for the treatment of relapsing-remitting multiple sclerosis. Experimental studies suggest that glatiramer acetate might also work in other neuroinflammatory or neurodegenerative diseases apart from multiple sclerosis. Findings We evaluated the efficacy of glatiramer acetate in a mouse model of brain ischemia/reperfusion injury. 60 min of transient middle cerebral artery occlusion was induced in male C57Bl/6 mice. Pretreatment with glatiramer acetate (3.5 mg/kg bodyweight) 30 min before the induction of stroke did not reduce lesion volumes or improve functional outcome on day 1. Conclusions Glatiramer acetate failed to protect from acute ischemic stroke in our hands. Further studies are needed to assess the true therapeutic potential of glatiramer acetate and related immunomodulators in brain ischemia.}, language = {en} } @article{GolombeckWessigMonoranuetal.2013, author = {Golombeck, Stefanie Kristin and Wessig, Carsten and Monoranu, Camelia-Maria and Sch{\"u}tz, Ansgar and Solymosi, Laszlo and Melzer, Nico and Kleinschnitz, Christoph}, title = {Fatal atypical reversible posterior leukoencephalopathy syndrome: a case report}, series = {Journal of Medical Case Reports}, volume = {7}, journal = {Journal of Medical Case Reports}, number = {14}, doi = {10.1186/1752-1947-7-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135517}, year = {2013}, abstract = {Introduction: Reversible posterior leukoencephalopathy syndrome - a reversible subacute global encephalopathy clinically presenting with headache, altered mental status, visual symptoms such as hemianopsia or cortical blindness, motor symptoms, and focal or generalized seizures - is characterized by a subcortical vasogenic edema symmetrically affecting posterior brain regions. Complete reversibility of both clinical signs and magnetic resonance imaging lesions is regarded as a defining feature of reversible posterior leukoencephalopathy syndrome. Reversible posterior leukoencephalopathy syndrome is almost exclusively seen in the setting of a predisposing clinical condition, such as pre-eclampsia, systemic infections, sepsis and shock, certain autoimmune diseases, various malignancies and cytotoxic chemotherapy, transplantation and concomitant immunosuppression (especially with calcineurin inhibitors) as well as episodes of abrupt hypertension. We describe for the first time clinical, radiological and histological findings in a case of reversible posterior leukoencephalopathy syndrome with an irreversible and fatal outcome occurring in the absence of any of the known predisposing clinical conditions except for a hypertensive episode. Case presentation: A 58-year-old Caucasian woman presented with a two-week history of subacute and progressive occipital headache, blurred vision and imbalance of gait and with no evidence for raised arterial blood pressure during the two weeks previous to admission. Her past medical history was unremarkable except for controlled arterial hypertension. Cerebral magnetic resonance imaging demonstrated cortical and subcortical lesions with combined vasogenic and cytotoxic edema atypical for both venous congestion and arterial infarction. Routine laboratory and cerebrospinal fluid parameters were normal. The diagnosis of reversible posterior leukoencephalopathy syndrome was established. Within hours after admission the patient showed a rapidly decreasing level of consciousness, extension and flexion synergisms, bilaterally extensor plantar responses and rapid cardiopulmonary decompensation requiring ventilatory and cardiocirculatory support. Follow-up cerebral imaging demonstrated widespread and confluent cytotoxic edematous lesions in different arterial territories, global cerebral swelling, and subsequent upper and lower brainstem herniation. Four days after admission, the patient was declared dead because of brain death. Conclusion: This case demonstrates that fulminant and fatal reversible posterior leukoencephalopathy syndrome may occur spontaneously, that is, in the absence of any of the known predisposing systemic conditions.}, language = {en} } @article{EhlingGoebBittneretal.2013, author = {Ehling, Petra and G{\"o}b, Eva and Bittner, Stefan and Budde, Thomas and Ludwig, Andreas and Kleinschnitz, Christoph and Meuth, Sven G.}, title = {Ischemia-induced cell depolarization: does the hyperpolarization-activated cation channel HCN2 affect the outcome after stroke in mice?}, series = {Experimental \& Translational Stroke Medicine}, volume = {5}, journal = {Experimental \& Translational Stroke Medicine}, number = {16}, doi = {10.1186/2040-7378-5-16}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131887}, year = {2013}, abstract = {Background Brain ischemia is known to include neuronal cell death and persisting neurological deficits. A lack of oxygen and glucose are considered to be key mediators of ischemic neurodegeneration while the exact mechanisms are yet unclear. In former studies the expression of two different two-pore domain potassium \((K_{2P})\) channels (TASK1, TREK1) were shown to ameliorate neuronal damage due to cerebral ischemia. In neurons, TASK channels carrying hyperpolarizing \(K^+\) leak currents, and the pacemaker channel HCN2, carrying depolarizing \(I_h\), stabilize the membrane potential by a mutual functional interaction. It is assumed that this ionic interplay between TASK and HCN2 channels enhances the resistance of neurons to insults accompanied by extracellular pH shifts. Methods In C57Bl/6 (wildtype, WT), \(hcn2^{+/+}\) and \(hcn2^{-/-}\) mice we used an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of HCN2 in stroke formation. Subsequent analyses comprise behavioural tests and hcn2 gene expression assays. Results After 60 min of tMCAO induction in WT mice, we collected tissue samples at 6, 12, and 24 h after reperfusion. In the infarcted neocortex, hcn2 expression analyses revealed a nominal peak of hcn2 expression 6 h after reperfusion with a tendency towards lower expression levels with longer reperfusion times. Hcn2 gene expression levels in infarcted basal ganglia did not change after 6 h and 12 h. Only at 24 h after reperfusion, hcn2 expression significantly decreases by ~55\%. However, 30 min of tMCAO in hcn2-/- as well as hcn2+/+ littermates induced similar infarct volumes. Behavioural tests for global neurological function (Bederson score) and motor function/coordination (grip test) were performed at day 1 after surgery. Again, we found no differences between the groups. Conclusions Here, we hypothesized that the absence of HCN2, an important functional counter player of TASK channels, affects neuronal survival during stroke-induced tissue damage. However, together with a former study on TASK3 these results implicate that both TASK3 and HCN2 which were supposed to be neuroprotective due to their pH-dependency, do not influence ischemic neurodegeneration during stroke in the tMCAO model.}, language = {en} } @article{GolombeckWessigMonoranuetal.2013, author = {Golombeck, Stefanie Kristin and Wessig, Carsten and Monoranu, Camelia-Maria and Sch{\"u}tz, Ansgar and Solymosi, Laszlo and Melzer, Niko and Kleinschnitz, Christoph}, title = {Fatal atypical reversible posterior leukoencephalopathy syndrome: a case report}, series = {Journal of Medical Case Reports}, volume = {7}, journal = {Journal of Medical Case Reports}, number = {14}, doi = {10.1186/1752-1947-7-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129456}, year = {2013}, abstract = {Introduction: Reversible posterior leukoencephalopathy syndrome - a reversible subacute global encephalopathy clinically presenting with headache, altered mental status, visual symptoms such as hemianopsia or cortical blindness, motor symptoms, and focal or generalized seizures - is characterized by a subcortical vasogenic edema symmetrically affecting posterior brain regions. Complete reversibility of both clinical signs and magnetic resonance imaging lesions is regarded as a defining feature of reversible posterior leukoencephalopathy syndrome. Reversible posterior leukoencephalopathy syndrome is almost exclusively seen in the setting of a predisposing clinical condition, such as pre-eclampsia, systemic infections, sepsis and shock, certain autoimmune diseases, various malignancies and cytotoxic chemotherapy, transplantation and concomitant immunosuppression (especially with calcineurin inhibitors) as well as episodes of abrupt hypertension. We describe for the first time clinical, radiological and histological findings in a case of reversible posterior leukoencephalopathy syndrome with an irreversible and fatal outcome occurring in the absence of any of the known predisposing clinical conditions except for a hypertensive episode. Case presentation: A 58-year-old Caucasian woman presented with a two-week history of subacute and progressive occipital headache, blurred vision and imbalance of gait and with no evidence for raised arterial blood pressure during the two weeks previous to admission. Her past medical history was unremarkable except for controlled arterial hypertension. Cerebral magnetic resonance imaging demonstrated cortical and subcortical lesions with combined vasogenic and cytotoxic edema atypical for both venous congestion and arterial infarction. Routine laboratory and cerebrospinal fluid parameters were normal. The diagnosis of reversible posterior leukoencephalopathy syndrome was established. Within hours after admission the patient showed a rapidly decreasing level of consciousness, extension and flexion synergisms, bilaterally extensor plantar responses and rapid cardiopulmonary decompensation requiring ventilatory and cardiocirculatory support. Follow-up cerebral imaging demonstrated widespread and confluent cytotoxic edematous lesions in different arterial territories, global cerebral swelling, and subsequent upper and lower brainstem herniation. Four days after admission, the patient was declared dead because of brain death. Conclusion: This case demonstrates that fulminant and fatal reversible posterior leukoencephalopathy syndrome may occur spontaneously, that is, in the absence of any of the known predisposing systemic conditions.}, language = {en} } @article{FluriHeinenKleinschnitz2013, author = {Fluri, Felix and Heinen, Florian and Kleinschnitz, Christoph}, title = {Intravenous Thrombolysis in a Stroke Patient Receiving Rivaroxaban}, series = {Cerebrovascular Disease Extra}, volume = {2013}, journal = {Cerebrovascular Disease Extra}, number = {3}, doi = {10.1159/000355839}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128816}, pages = {153-155}, year = {2013}, abstract = {No abstract available.}, language = {en} } @article{LinkerMagnusKornetal.2013, author = {Linker, Ralf A. and Magnus, Tim and Korn, Thomas and Kleinschnitz, Christoph and Meuth, Sven G.}, title = {Report on the 5'th scientific meeting of the "Verein zur F{\"o}rderung des Wissenschaftlichen Nachwuchses in der Neurologie" (NEUROWIND e.V.) held in Motzen, Germany, Oct. 25th - Oct. 27th, 2013}, series = {Experimental \& Translational Stroke Medicine}, volume = {5}, journal = {Experimental \& Translational Stroke Medicine}, number = {15}, doi = {10.1186/2040-7378-5-15}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129230}, year = {2013}, abstract = {From october 25th - 27th 2013, the 5th NEUROWIND e.V. meeting was held in Motzen, Brandenburg, Germany. This year more than 60 doctoral students and postdocs from over 25 different groups working in German university hospitals or research institutes attended the meeting to discuss their latest findings in the fields of neuroimmunology, neurodegeneration and neurovascular research. All participants appreciated the stimulating environment in Motzen, Brandenburg, and people took the opportunity for scientific exchange, discussion about ongoing projects and already started further collaborations. Like in the previous years, the symposium was regarded as a very well organized platform to support research of young investigators in Germany. According to the major aim of NEUROWIND e.V. to support younger researchers in Germany the 3rd NEUROWIND YOUNG SCIENTIST AWARD for experimental neurology was awarded to Ruth Stassart working in the group of Klaus Armin Nave and Wolfgang Br{\"u}ck (MPI G{\"o}ttingen and Department of Neuropathology, G{\"o}ttingen Germany). The successful work was published in Nature Neuroscience entitled "A role for Swann cell-derived neuregulin-1 in remyelination". This outstanding paper deals with the function of Schwann cell neuregulin as an endogenous factor for myelin repair. The award is endowed with 20.000 Euro sponsored by Merck Serono GmbH, Darmstadt, Germany (unrestricted educational grant). This year's keynote lecture was given by Albert Ludolph, Head of the Department of Neurology at the University Clinic of Ulm. Dr. Ludolph highlighted the particular role of individual scientists for the development of research concepts in Alzheimer´s disease (AD) and frontotemporal dementia (FTD).}, language = {en} } @article{EhlingGoebBittneretal.2013, author = {Ehling, Petra and G{\"o}b, Eva and Bittner, Stefan and Budde, Thomas and Ludwig, Andreas and Kleinschnitz, Christoph and Meuth, Sven G.}, title = {Ischemia-induced cell depolarization: does the hyperpolarization-activated cation channel HCN2 affect the outcome after stroke in mice?}, series = {Experimental \& Translational Stroke Medicine}, volume = {5}, journal = {Experimental \& Translational Stroke Medicine}, number = {16}, doi = {10.1186/2040-7378-5-16}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129240}, year = {2013}, abstract = {Background Brain ischemia is known to include neuronal cell death and persisting neurological deficits. A lack of oxygen and glucose are considered to be key mediators of ischemic neurodegeneration while the exact mechanisms are yet unclear. In former studies the expression of two different two-pore domain potassium \((K_{2P})\) channels (TASK1, TREK1) were shown to ameliorate neuronal damage due to cerebral ischemia. In neurons, TASK channels carrying hyperpolarizing \(K^+\) leak currents, and the pacemaker channel HCN2, carrying depolarizing Ih, stabilize the membrane potential by a mutual functional interaction. It is assumed that this ionic interplay between TASK and HCN2 channels enhances the resistance of neurons to insults accompanied by extracellular pH shifts. Methods In C57Bl/6 (wildtype, WT), \(hcn2^{+/+}\) and \(hcn2^{-/-}\) mice we used an in vivo model of cerebral ischemia (transient middle cerebral artery occlusion (tMCAO)) to depict a functional impact of HCN2 in stroke formation. Subsequent analyses comprise behavioural tests and hcn2 gene expression assays. Results After 60 min of tMCAO induction in WT mice, we collected tissue samples at 6, 12, and 24 h after reperfusion. In the infarcted neocortex, hcn2 expression analyses revealed a nominal peak of hcn2 expression 6 h after reperfusion with a tendency towards lower expression levels with longer reperfusion times. Hcn2 gene expression levels in infarcted basal ganglia did not change after 6 h and 12 h. Only at 24 h after reperfusion, hcn2 expression significantly decreases by ~55\%. However, 30 min of tMCAO in hcn2-/- as well as hcn2+/+ littermates induced similar infarct volumes. Behavioural tests for global neurological function (Bederson score) and motor function/coordination (grip test) were performed at day 1 after surgery. Again, we found no differences between the groups. Conclusions Here, we hypothesized that the absence of HCN2, an important functional counter player of TASK channels, affects neuronal survival during stroke-induced tissue damage. However, together with a former study on TASK3 these results implicate that both TASK3 and HCN2 which were supposed to be neuroprotective due to their pH-dependency, do not influence ischemic neurodegeneration during stroke in the tMCAO model.}, language = {en} } @article{KleinschnitzMenclGarzetal.2013, author = {Kleinschnitz, Christoph and Mencl, Stine and Garz, Cornelia and Niklass, Solveig and Braun, Holger and G{\"o}b, Eva and Homola, Gy{\"o}rgy and Heinze, Hans-Jochen and Reymann, Klaus G. and Schreiber, Stefanie}, title = {Early microvascular dysfunction in cerebral small vessel disease is not detectable on 3.0 Tesla magnetic resonance imaging: a longitudinal study in spontaneously hypertensive stroke-prone rats}, series = {Experimental \& Translational Stroke Medicine}, journal = {Experimental \& Translational Stroke Medicine}, doi = {10.1186/2040-7378-5-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-97056}, year = {2013}, abstract = {Background Human cerebral small vessel disease (CSVD) has distinct histopathologic and imaging findings in its advanced stages. In spontaneously hypertensive stroke-prone rats (SHRSP), a well-established animal model of CSVD, we recently demonstrated that cerebral microangiopathy is initiated by early microvascular dysfunction leading to the breakdown of the blood-brain barrier and an activated coagulatory state resulting in capillary and arteriolar erythrocyte accumulations (stases). In the present study, we investigated whether initial microvascular dysfunction and other stages of the pathologic CSVD cascade can be detected by serial magnetic resonance imaging (MRI). Findings Fourteen SHRSP and three control (Wistar) rats (aged 26-44 weeks) were investigated biweekly by 3.0 Tesla (3 T) MRI. After perfusion, brains were stained with hematoxylin-eosin and histology was correlated with MRI data. Three SHRSP developed terminal CSVD stages including cortical, hippocampal, and striatal infarcts and macrohemorrhages, which could be detected consistently by MRI. Corresponding histology showed small vessel thromboses and increased numbers of small perivascular bleeds in the infarcted areas. However, 3 T MRI failed to visualize intravascular erythrocyte accumulations, even in those brain regions with the highest densities of affected vessels and the largest vessels affected by stases, as well as failing to detect small perivascular bleeds. Conclusion Serial MRI at a field strength of 3 T failed to detect the initial microvascular dysfunction and subsequent small perivascular bleeds in SHRSP; only terminal stages of cerebral microangiopathy were reliably detected. Further investigations at higher magnetic field strengths (7 T) using blood- and flow-sensitive sequences are currently underway.}, language = {en} } @article{GunrebenGeisKleinschnitz2013, author = {Gunreben, Ignaz and Geis, Christian and Kleinschnitz, Christoph}, title = {Acute tetraparesis secondary to bilateral precentral gyral cerebral ischemia: a case report}, series = {Journal of Medical Case Reports}, journal = {Journal of Medical Case Reports}, doi = {10.1186/1752-1947-7-61}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96179}, year = {2013}, abstract = {Introduction Sudden tetraparesis represents a neurological emergency and is most often caused by traumatic spinal cord injury, spinal epidural bleeding or brainstem ischemia and less frequently by medial disc herniation or spinal ischemia. Case presentation Here we report the rare case of an 82-year-old Caucasian man who developed severe tetraparesis four days after radical cystoprostatectomy. An emergency diagnostic study for spinal cord affection was normal. Brain magnetic resonance imaging revealed acute bilateral ischemic strokes in the precentral gyri as the underlying cause. Conclusions This case report underlines the need to also consider unusual causes of tetraparesis in an emergency situation apart from spinal cord or brain stem injury in order not to leave severe symptomatology unclear and possibly miss therapeutic options.}, language = {en} } @article{BoltzeKleinschnitzReymannetal.2012, author = {Boltze, Johannes and Kleinschnitz, Christoph and Reymann, Klaus G. and Reiser, Georg and Wagner, Daniel-Christoph and Kranz, Alexander and Michalski, Dominik}, title = {Neurovascular pathophysiology in cerebral ischemia, dementia and the ageing brain - current trends in basic, translational and clinical research}, series = {Experimental \& Translational Stroke Medicine}, volume = {4}, journal = {Experimental \& Translational Stroke Medicine}, number = {14}, doi = {doi:10.1186/2040-7378-4-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126679}, year = {2012}, abstract = {The 7th International Symposium on Neuroprotection and Neurorepair was held from May 2nd to May 5th, 2012 in Potsdam, Germany. The symposium, which directly continues the successful Magdeburg meeting series, attracted over 330 colleagues from 29 countries to discuss recent findings and advances in the field. The focus of the 2012 symposium was widened from stroke and traumatic brain injury to neurodegenerative diseases, notably dementia, and more generally the ageing brain. Thereby, emphasis was given on neurovascular aspects of neurodegeneration and stroke including the blood-brain barrier, recent findings regarding the pathomechanism of Alzheimer's disease, and brain imaging approaches. In addition, neurobiochemical aspects of neuroprotection, the role of astrogliosis, the clinical progress of cell-based approaches as well as translational hurdles and opportunities were discussed in-depth. This review summarizes some of the most stimulating discussions and reports from the meeting.}, language = {en} } @article{KraftDeMeyerKleinschnitz2012, author = {Kraft, Peter and De Meyer, Simon F. and Kleinschnitz, Christoph}, title = {Next-Generation Antithrombotics in Ischemic Stroke: Preclinical Perspective on 'Bleeding-Free Antithrombosis'}, series = {Journal of Cerebral Blood Flow and Metabolism}, volume = {32}, journal = {Journal of Cerebral Blood Flow and Metabolism}, number = {10}, doi = {10.1038/jcbfm.2012.108}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126538}, pages = {1831-1840}, year = {2012}, abstract = {The present antithrombotic drugs used to treat or prevent ischemic stroke have significant limitations: either they show only moderate efficacy (platelet inhibitors), or they significantly increase the risk for hemorrhages (thrombolytics, anticoagulants). Although most strokes are caused by thrombotic or embolic vessel occlusions, the pathophysiological role of platelets and coagulation is largely unclear. The introduction of novel transgenic mouse models and specific coagulation inhibitors facilitated a detailed analysis of molecular pathways mediating thrombus formation in models of acute ischemic stroke. Prevention of early platelet adhesion to the damaged vessel wall by blocking platelet surface receptors glycoprotein Ib alpha (GPIbα) or glycoprotein VI (GPVI) protects from stroke without provoking bleeding complications. In addition, downstream signaling of GPIbα and GPVI has a key role in platelet calcium homeostasis and activation. Finally, the intrinsic coagulation cascade, activated by coagulation factor XII (FXII), has only recently been identified as another important mediator of thrombosis in cerebrovascular disease, thereby disproving established concepts. This review summarizes the latest insights into the pathophysiology of thrombus formation in the ischemic brain. Potential clinical merits of novel platelet inhibitors and anticoagulants as powerful and safe tools to combat ischemic stroke are discussed.}, language = {en} }