title: Leukocyte plugging and cortical capillary flow after subarachnoid hemorrhage.
abstract: It is believed that increased intracranial pressure immediately after subarachnoid hemorrhage (SAH) causes extensive brain ischemia and results in worsening clinical status. Arterial flow to the cerebral surfaces is clinically well maintained during clipping surgery regardless of the severity of the World Federation of Neurological Societies grade after SAH. To explore what kinds of changes occur in the cortical microcirculation, not at the cerebral surface, we examined cortical microcirculation after SAH using two-photon laser scanning microscopy (TPLSM).
  
  
  
  SAH was induced in mice with an endovascular perforation model. Following continuous injection of rhodamine 6G, velocities of labeled platelets and leukocytes and unlabeled red blood cells (RBCs) were measured in the cortical capillaries 60 min after SAH with a line-scan method using TPLSM, and the data were compared to a sham group and P-selectin monoclonal antibody-treated group.
  
  
  
  Velocities of leukocytes, platelets, and RBCs in capillaries decreased significantly 60 min after SAH. Rolling and adherent leukocytes suddenly prevented other blood cells from flowing in the capillaries. Flowing blood cells also decreased significantly in each capillary after SAH. This no-reflow phenomenon induced by plugging leukocytes was often observed in the SAH group but not in the sham group. The decreased velocities of blood cells were reversed by pretreatment with the monoclonal antibody of P-selection, an adhesion molecule expressed on the surfaces of both endothelial cells and platelets.
  
  
  
  SAH caused sudden worsening of cortical microcirculation at the onset. Leukocyte plugging in capillaries is one of the reasons why cortical microcirculation is aggravated after SAH.
authors.affiliation: Department of Neurosurgery, Saitama Medical Center, Jichi Medical University, 1-847 Amanumacho Omiya-ku, Saitama-city, Saitama, 330-8503, Japan. m.ishikawa@jichi.ac.jp.|Department of Biochemistry School of Medicine, Keio University, Tokyo, Japan. m.ishikawa@jichi.ac.jp.
authors.forename: Mami
authors.initials: M
authors.lastname: Ishikawa
authors.affiliation: Department of Biochemistry School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kajimura
authors.affiliation: Department of Biochemistry School of Medicine, Keio University, Tokyo, Japan.|Department of Stem Cell Biology, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Morikawa
authors.affiliation: Graduate School of Science and Technology, Keio University, Kanagawa, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tsukada
authors.affiliation: Department of Biochemistry School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Tsuji
authors.affiliation: Department of Neurosurgery, Saitama Medical Center, Jichi Medical University, 1-847 Amanumacho Omiya-ku, Saitama-city, Saitama, 330-8503, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Kusaka
authors.affiliation: Department of Neurosurgery, Saitama Medical Center, Jichi Medical University, 1-847 Amanumacho Omiya-ku, Saitama-city, Saitama, 330-8503, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Biochemistry School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Suematsu
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D007962:Leukocytes / Q000473:pathology*; D008297:Male; D051379:Mice; D008833:Microcirculation; D013345:Subarachnoid Hemorrhage / Q000097:blood / Q000503:physiopathology*
keywords: Cerebral microcirculation; Line scan; No reflow; P-selectin; Two photon