@article{PotreckMutkeWeylandetal.2021,
  author    = {Potreck, Arne and Mutke, Matthias A. and Weyland, Charlotte S. and Pfaff, Johannes A. R. and Ringleb, Peter A. and Mundiyanapurath, Sibu and M{\"o}hlenbruch, Markus A. and Heiland, Sabine and Pham, Mirko and Bendszus, Martin and Hoffmann, Angelika},
  title     = {Combined Perfusion and Permeability Imaging Reveals Different Pathophysiologic Tissue Responses After Successful Thrombectomy},
  series = {Translational Stroke Research},
  volume    = {12},
  journal   = {Translational Stroke Research},
  number    = {5},
  issn      = {1868-4483},
  doi       = {10.1007/s12975-020-00885-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-308946},
  pages     = {799-807},
  year      = {2021},
  abstract  = {Despite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on ktrans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median ktrans elevation (IQR) of 0.77 (0.41-1.4) min-1 and was found in all 7 cases of hypoperfusion (100\%), in 10 of 16 cases of hyperperfusion (63\%), and in only three of 13 cases with unaffected perfusion (23\%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56-0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10-0.82]) compared to hyperperfusion (PPV = 0.93 [0.68-1.0]) or unaffected perfusion (PPV = 1.0 [0.75-1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression.},
  language  = {en}
}
@article{BieberFoersterHaefelietal.2021,
  author    = {Bieber, Michael and Foerster, Kathrin I. and Haefeli, Walter E. and Pham, Mirko and Schuhmann, Michael K. and Kraft, Peter},
  title     = {Treatment with edoxaban attenuates acute stroke severity in mice by reducing blood-brain barrier damage and inflammation},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {18},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22189893},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284481},
  year      = {2021},
  abstract  = {Patients with atrial fibrillation and previous ischemic stroke (IS) are at increased risk of cerebrovascular events despite anticoagulation. In these patients, treatment with non-vitamin K oral anticoagulants (NOAC) such as edoxaban reduced the probability and severity of further IS without increasing the risk of major bleeding. However, the detailed protective mechanism of edoxaban has not yet been investigated in a model of ischemia/reperfusion injury. Therefore, in the current study we aimed to assess in a clinically relevant setting whether treatment with edoxaban attenuates stroke severity, and whether edoxaban has an impact on the local cerebral inflammatory response and blood-brain barrier (BBB) function after experimental IS in mice. Focal cerebral ischemia was induced by transient middle cerebral artery occlusion in male mice receiving edoxaban, phenprocoumon or vehicle. Infarct volumes, functional outcome and the occurrence of intracerebral hemorrhage were assessed. BBB damage and the extent of local inflammatory response were determined. Treatment with edoxaban significantly reduced infarct volumes and improved neurological outcome and BBB function on day 1 and attenuated brain tissue inflammation. In summary, our study provides evidence that edoxaban might exert its protective effect in human IS by modulating different key steps of IS pathophysiology, but further studies are warranted.},
  language  = {en}
}
@article{StrinitzPhamMaerzetal.2021,
  author    = {Strinitz, Marc and Pham, Mirko and M{\"a}rz, Alexander G. and Feick, J{\"o}rn and Weidner, Franziska and Vogt, Marius L. and Essig, Fabian and Neugebauer, Hermann and Stoll, Guido and Schuhmann, Michael K. and Kollikowski, Alexander M.},
  title     = {Immune cells invade the collateral circulation during human stroke: prospective replication and extension},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {17},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22179161},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284281},
  year      = {2021},
  abstract  = {It remains unclear if principal components of the local cerebral stroke immune response can be reliably and reproducibly observed in patients with acute large-vessel-occlusion (LVO) stroke. We prospectively studied a large independent cohort of n = 318 consecutive LVO stroke patients undergoing mechanical thrombectomy during which cerebral blood samples from within the occluded anterior circulation and systemic control samples from the ipsilateral cervical internal carotid artery were obtained. An extensive protocol was applied to homogenize the patient cohort and to standardize the procedural steps of endovascular sample collection, sample processing, and laboratory analyses. N = 58 patients met all inclusion criteria. (1) Mean total leukocyte counts were significantly higher within the occluded ischemic cerebral vasculature (I) vs. intraindividual systemic controls (S): +9.6\%, I: 8114/µL ± 529 vs. S: 7406/µL ± 468, p = 0.0125. (2) This increase was driven by neutrophils: +12.1\%, I: 7197/µL ± 510 vs. S: 6420/µL ± 438, p = 0.0022. Leukocyte influx was associated with (3) reduced retrograde collateral flow (R\(^2\) = 0.09696, p = 0.0373) and (4) greater infarct extent (R\(^2\) = 0.08382, p = 0.032). Despite LVO, leukocytes invade the occluded territory via retrograde collateral pathways early during ischemia, likely compromising cerebral hemodynamics and tissue integrity. This inflammatory response can be reliably observed in human stroke by harvesting immune cells from the occluded cerebral vascular compartment.},
  language  = {en}
}
@article{EssigBabilonVollmuthetal.2021,
  author    = {Essig, Fabian and Babilon, Lilith and Vollmuth, Christoph and Kollikowski, Alexander M. and Pham, Mirko and Solymosi, L{\´a}szl{\´o} and Haeusler, Karl Georg and Kraft, Peter and Stoll, Guido and Schuhmann, Michael K.},
  title     = {High mobility group box 1 protein in cerebral thromboemboli},
  series = {International Journal of Molecular Sciences},
  volume    = {22},
  journal   = {International Journal of Molecular Sciences},
  number    = {20},
  issn      = {1422-0067},
  doi       = {10.3390/ijms222011276},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265568},
  year      = {2021},
  abstract  = {High-mobility group box 1 protein (HMGB1) is a damage-associated molecular pattern (DAMP) involved in neutrophil extracellular trap (NET) formation and thrombosis. NETs are regularly found in cerebral thromboemboli. We here analyzed associated HMGB1 expression in human thromboemboli retrieved via mechanical thrombectomy from 37 stroke patients with large vessel occlusion. HMGB1 was detected in all thromboemboli, accounting for 1.7\% (IQR 0.6-6.2\%) of the total thromboemboli area and was found to be colocalized with neutrophils and NETs and in spatial proximity to platelets. Correlation analysis revealed that the detection of HMGB1 was strongly related to the number of neutrophils (r = 0.58, p = 0.0002) and platelets (r = 0.51, p = 0.001). Our results demonstrate that HMGB1 is a substantial constituent of thromboemboli causing large vessel occlusion stroke.},
  language  = {en}
}
@article{SchuhmannBieberFrankeetal.2021,
  author    = {Schuhmann, Michael K. and Bieber, Michael and Franke, Maximilian and Kollikowski, Alexander M. and Stegner, David and Heinze, Katrin G. and Nieswandt, Bernhard and Pham, Mirko and Stoll, Guido},
  title     = {Platelets and lymphocytes drive progressive penumbral tissue loss during middle cerebral artery occlusion in mice},
  series = {Journal of Neuroinflammation},
  volume    = {18},
  journal   = {Journal of Neuroinflammation},
  number    = {1},
  doi       = {10.1186/s12974-021-02095-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259172},
  pages     = {46},
  year      = {2021},
  abstract  = {Background In acute ischemic stroke, cessation of blood flow causes immediate tissue necrosis within the center of the ischemic brain region accompanied by functional failure in the surrounding brain tissue designated the penumbra. The penumbra can be salvaged by timely thrombolysis/thrombectomy, the only available acute stroke treatment to date, but is progressively destroyed by the expansion of infarction. The underlying mechanisms of progressive infarction are not fully understood. Methods To address mechanisms, mice underwent filament occlusion of the middle cerebral artery (MCAO) for up to 4 h. Infarct development was compared between mice treated with antigen-binding fragments (Fab) against the platelet surface molecules GPIb (p0p/B Fab) or rat immunoglobulin G (IgG) Fab as control treatment. Moreover, Rag1\(^{-/-}\) mice lacking T-cells underwent the same procedures. Infarct volumes as well as the local inflammatory response were determined during vessel occlusion. Results We show that blocking of the platelet adhesion receptor, glycoprotein (GP) Ibα in mice, delays cerebral infarct progression already during occlusion and thus before recanalization/reperfusion. This therapeutic effect was accompanied by decreased T-cell infiltration, particularly at the infarct border zone, which during occlusion is supplied by collateral blood flow. Accordingly, mice lacking T-cells were likewise protected from infarct progression under occlusion. Conclusions Progressive brain infarction can be delayed by blocking detrimental lymphocyte/platelet responses already during occlusion paving the way for ultra-early treatment strategies in hyper-acute stroke before recanalization.},
  language  = {en}
}