title: Alteplase Reduces Downstream Microvascular Thrombosis and Improves the Benefit of Large Artery Recanalization in Stroke.
abstract: OBJECTIVE
  Downstream microvascular thrombosis (DMT) is known to be a contributing factor to incomplete reperfusion in acute ischemic stroke. The aim of this study was to determine the timing of DMT with intravital imaging and to test the hypothesis that intravenous alteplase infusion could reduce DMT in a transient middle cerebral artery occlusion (MCAO) rat stroke model.
  
  
  METHODS
  Rats were subjected to 60-minute transient MCAO. Alteplase (10 mg/kg) was administered 30 minutes after the beginning of MCAO. Real-time intravital fluorescence microscopy through a dura-sparing craniotomy was used to visualize circulating blood cells and fibrinogen. Cerebral microvessel patency was quantitatively evaluated by fluorescein isothiocyanate-dextran perfusion.
  
  
  RESULTS
  Immediately after MCAO, platelet and leukocyte accumulation were observed mostly in the venous compartment. Within 30 minutes after MCAO, microthrombi and parietal fibrin deposits were detected in postcapillary microvessels. Alteplase treatment significantly (P=0.006) reduced infarct volume and increased the percentage of perfused vessels during MCAO (P=0.02) compared with saline. Plasma levels of fibrinogen from alteplase-treated rats showed a rapid and profound hypofibrinogenemia. In vitro platelet aggregation demonstrated that alteplase reduced platelet aggregation (P=0.0001) and facilitated platelet disaggregation (P=0.001). These effects were reversible in the presence of exogenous fibrinogen.
  
  
  CONCLUSIONS
  Our data demonstrate that DMT is an early phenomenon initiated before recanalization. We further show that alteplase-dependent maintenance of downstream perfusion during MCAO improves acute ischemic stroke outcome through a fibrinogen-dependent platelet aggregation reduction. Our results indicate that early targeting of DMT represents a therapeutic strategy to improve the benefit of large artery recanalization in acute ischemic stroke.
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.). jpdesilles@gmail.com.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Desilles
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Stephane
authors.initials: S
authors.lastname: Loyau
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Varouna
authors.initials: V
authors.lastname: Syvannarath
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Jaime
authors.initials: J
authors.lastname: Gonzalez-Valcarcel
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Marie
authors.initials: M
authors.lastname: Cantier
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Liliane
authors.initials: L
authors.lastname: Louedec
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Bertrand
authors.initials: B
authors.lastname: Lapergue
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Pierre
authors.initials: P
authors.lastname: Amarenco
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Nadine
authors.initials: N
authors.lastname: Ajzenberg
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Martine
authors.initials: M
authors.lastname: Jandrot-Perrus
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Michel
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Benoit
authors.initials: B
authors.lastname: Ho-Tin-Noe
authors.affiliation: From the Univ Paris Diderot, Sorbonne Paris Cite, Laboratory of Vascular Translational Science, U1148 Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France (J.-P.D., S.L., V.S., J.G.-V., M.C., L.L., P.A., N.A., M.J.-P., J.-B.M., B.H.-T.-N., M.M.); Division of Neurology, Stroke Center, Foch Hospital, University Versailles Saint-Quentin en Yvelines, Paris, France (B.L.); Departments of Neurology and Stroke Center (P.A.) and Hematology (N.A.), AP-HP, Bichat Hospital, Paris, France; and Department of Neurology and Stroke Center, AP-HP, Lariboisière Hospital, DHU Neurovasc, Paris, France (M.M.).
authors.forename: Mikael
authors.initials: M
authors.lastname: Mazighi
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects; D004195:Disease Models, Animal; D005337:Fibrin / Q000187:drug effects / Q000378:metabolism; D005340:Fibrinogen / Q000187:drug effects / Q000378:metabolism; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology / Q000628:therapy*; D020767:Intracranial Thrombosis / Q000473:pathology / Q000517:prevention & control*; D007962:Leukocytes / Q000187:drug effects; D008297:Male; D008856:Microscopy, Fluorescence; D055806:Microvessels / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*
chemical_list: D005343:Fibrinolytic Agents; D005337:Fibrin; D005340:Fibrinogen; D010959:Tissue Plasminogen Activator
keywords: blood platelets; fibrinogen; fibrinolysis; microcirculation; stroke