title: Microstructural abnormality in white matter, regulatory T lymphocytes, and depressive symptoms after stroke.
abstract: BACKGROUND
  The purpose of the present study was to investigate the existence of microstructure abnormalities in the white matter circuit in stroke patients and its relationship to depressive episodes. To target the prevention of depression, we also investigated the relationship between lymphocyte subsets and cerebral abnormalities in patients.
  
  
  METHODS
  Participants included 18 patients with acute ischemic stroke and 22 healthy control subjects. Diffusion tensor imaging was performed. Whole-brain voxel-based analysis was used to compare fractional anisotropy (FA) between groups. Blood samples were obtained, and the lymphocyte subsets were evaluated using flow cytometry. Follow-up examinations were conducted on 12 patients at 6 months.
  
  
  RESULTS
  FA was decreased in the bilateral anterior limb of the internal capsule in stroke patients. At the 6-month follow-up examination, there was a significant increase in FA, which was associated with a lower depression scale score. Patients showed a decreased percentage of circulated regulatory T lymphocytes, and the degree of reduction was related to the decrease in the FA value in the internal capsule.
  
  
  CONCLUSIONS
  FA reductions in the anterior limb of the internal capsule cause abnormality in the frontal-subcortical circuits and confer a biological vulnerability, which in combination with environmental stressors results in the onset of depression. Our findings also demonstrated the possibility of preventing post-stroke depression by targeting the role of regulatory T lymphocytes in brain tissue repair and regeneration after stroke.
authors.affiliation: Department of Neuropsychiatry, Nara Medical University, Kashihara; Department of Investigative Radiology, National Cerebral and Cardiovascular Center, Kobe, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Yasuno
authors.forename: Akihiko
authors.initials: A
authors.lastname: Taguchi
authors.forename: Akihide
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Katsufumi
authors.initials: K
authors.lastname: Kajimoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kazui
authors.forename: Takashi
authors.initials: T
authors.lastname: Kudo
authors.forename: Akie
authors.initials: A
authors.lastname: Kikuchi-Taura
authors.forename: Atsuo
authors.initials: A
authors.lastname: Sekiyama
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Kishimoto
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Iida
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Nagatsuka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000002:abnormalities / Q000378:metabolism* / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D003863:Depression / Q000473:pathology* / Q000523:psychology; D056324:Diffusion Tensor Imaging / Q000706:statistics & numerical data*; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D057566:Self Report; D020521:Stroke / Q000378:metabolism / Q000503:physiopathology*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology
keywords: diffusion tensor imaging; fractional anisotropy (FA); magnetic resonance imaging (MRI); post-stroke depression; regulatory T lymphocytes (Treg); stroke