@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{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{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{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} }