title: In vivo imaging of the mouse neurovascular unit under chronic cerebral hypoperfusion.
abstract: OBJECTIVE
  Proper brain function is maintained by an integrated system called the neurovascular unit (NVU) comprised cellular and acellular elements. Although the individual features of specific neurovascular components are understood, it is unknown how they respond to ischemic stress as a functional unit. Therefore, we established an in vivo imaging method and clarified the NVU response to chronic cerebral hypoperfusion.
  
  
  METHODS
  Green mice (b-act-EGFP) with SR101 plasma labeling were used in this experiment. A closed cranial window was made over the left somatosensory cortex. To mimic chronic cerebral hypoperfusion, mice were subjected to bilateral common carotid artery stenosis operations using microcoils. In vivo real-time imaging was performed using 2-photon laser-scanning microscopy during the preoperative period, and after 1 day and 1 and 2 weeks of bilateral common carotid artery stenosis or sham operations.
  
  
  RESULTS
  Our method allowed 3-dimensional observation of most of the components of the NVU, as well as dynamic capillary microcirculation. Under chronic cerebral hypoperfusion, we did not detect any structural changes of each cellular component in the NVU; however, impairment of microcirculation was detected over a prolonged period. In the pial small arteries and veins, rolling and adhesion of leukocyte were detected, more prominently in the latter. In the deep cortical capillaries, flow stagnation because of leukocyte plugging was frequently observed.
  
  
  CONCLUSIONS
  We established an in vivo imaging method for real-time visualization of the NVU. It seems that under chronic cerebral hypoperfusion, leukocyte activation has a critical role in microcirculation disturbance.
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.). ken-yata@mbk.nifty.com.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Yata
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Nishimura
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Miyuki
authors.initials: M
authors.lastname: Unekawa
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tomita
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Norihiro
authors.initials: N
authors.lastname: Suzuki
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Toshio
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Akira
authors.initials: A
authors.lastname: Mizoguchi
authors.affiliation: From the Department of Neurology (K.Y., H.T.), Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics (Y.N., T.T.), and Department of Neural Regeneration and Cell Communication (A.M.), Mie University Graduate School of Medicine, Tsu, Mie, Japan; and Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo, Japan (M.U., Y.T., N.S.).
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tomimoto
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology*; D049452:Green Fluorescent Proteins / Q000235:genetics; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal / Q000379:methods; D059906:Neuroimaging / Q000379:methods*
chemical_list: D049452:Green Fluorescent Proteins
keywords: astrocytes; leukocytes; microcirculation; microscopy, fluorescence, multiphoton; pericytes