title: Different expression of low density lipoprotein receptor and ApoE between young adult and old rat brains after ischemia.
abstract: OBJECTIVE
  Reduction of brain plasticity underlies the poor outcome of aged stroke patients. The molecular mechanism of plasticity reduction by aging is uncertain, but disturbed lipid metabolism may be implicated.
  
  
  METHODS
  We investigated the expression of low density lipoprotein receptors (LDL-R) and apolipoprotein E (ApoE), both of which play active roles in lipid metabolism in young adult and old rat brains after ischemia.
  
  
  RESULTS
  LDL-R, trivially expressed in the sham-operated brain neurons, was increased from day 1 and became prominent at days 7 and 21 at the peri-ischemic cortex. The magnitude was smaller in the old than in the young adult rats. ApoE was increased in the astrocytes and neurons of the peri-ischemic cortex at day 1, which became further pronounced in the neurons but not in the astrocytes at days 7 and 21. ApoE expression was again less prominent in the old animals at days 7 and 21.
  
  
  CONCLUSIONS
  As ApoE-containing lipoprotein is recruited via LDL-R, the present results suggest that old brains had less capability to induce LDL-R, which resulted in impaired recruitment of lipoprotein after the ischemic injury. Impaired lipid recruitment causes disturbance of synaptogenesis and thus brain plasticity reduction. This molecular mechanism may result in poor functional recovery of aged stroke patients.
authors.affiliation: Department of Neurology, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan. thayashi@cc.okayama-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamada
authors.forename: Guang
authors.initials: G
authors.lastname: Jin
authors.forename: Kentaro
authors.initials: K
authors.lastname: Deguchi
authors.forename: Shoko
authors.initials: S
authors.lastname: Nagotani
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Sehara
authors.forename: Hanzhe
authors.initials: H
authors.lastname: Zhang
authors.forename: Isao
authors.initials: I
authors.lastname: Nagano
authors.forename: Mikio
authors.initials: M
authors.lastname: Shoji
authors.forename: Koji
authors.initials: K
authors.lastname: Abe
mesh_terms: D000367:Age Factors; D000818:Animals; D001057:Apolipoproteins E / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D002452:Cell Count / Q000379:methods; D002540:Cerebral Cortex / Q000473:pathology; D005786:Gene Expression Regulation / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D009474:Neurons / Q000378:metabolism; D051381:Rats; D011973:Receptors, LDL / Q000378:metabolism*; D013997:Time Factors
chemical_list: D001057:Apolipoproteins E; D011973:Receptors, LDL