title: Glutamate-glutamine and GABA in brain of normal aged and patients with cognitive impairment.
abstract: OBJECTIVE
  To explore the changes of glutamate-glutamine (Glx) and gamma-aminobutyric acid (GABA) in the brain in normal old age and cognitive impairment using magnetic resonance spectroscopy (MRS).
  
  
  METHODS
  Seventeen normal young controls (NYC), 15 normal elderly controls (NEC), 21 patients with mild cognitive impairment (MCI) and 17 with Alzheimer disease (AD) patients were included in this study. Glx and GABA+ levels in the anterior cingulate cortex (ACC) and right hippocampus (rHP) were measured by using a MEGA-PRESS sequence. Glx/Cr and GABA+/Cr ratios were compared between NYC and NEC and between the three elderly groups using analysis of covariance (ANCOVA); the tissue fractions of voxels were used as covariates. The relationships between metabolite ratios and cognitive performance were analysed using Spearman correlation coefficients.
  
  
  RESULTS
  For NEC and NYC groups, Glx/Cr and GABA+/Cr ratios were lower in NEC in ACC and rHP. For the three elderly groups, Glx/Cr ratio was lower in AD in ACC compared to NEC and MCI; Glx/Cr ratio was lower in AD in rHP compared to NEC. There was no significant decrease for GABA+/Cr ratio.
  
  
  CONCLUSIONS
  Glx and GABA levels may decrease simultaneously in normal aged, and Glx level decreased predominantly in AD, and it is helpful in the early diagnosis of AD.
  
  
  CONCLUSIONS
  • Glx and GABA levels may decrease simultaneously in normal aged. • Glx level may decrease predominantly in Alzheimer disease. • The balance in excitatory-inhibitory systems may be broken in AD. • Decreased Glx level may be helpful in early diagnosis of AD.
authors.affiliation: Department of Radiology, First Central Clinical College, Tianjin Medical University, Tianjin, 300070, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Huang
authors.affiliation: Department of Radiology, Tianjin First Center Hospital, Tianjin, 300192, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of Radiology, Tianjin First Center Hospital, Tianjin, 300192, China.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Yin
authors.affiliation: MR Collaborations NE Asia, Siemens Healthcare, Beijing, 100102, China.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Qian
authors.affiliation: Department of Radiology, First Central Clinical College, Tianjin Medical University, Tianjin, 300070, China.
authors.forename: Susan
authors.initials: S
authors.lastname: Shrestha
authors.affiliation: Department of Radiology, Tianjin First Center Hospital, Tianjin, 300192, China. nihyan@sina.com.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Ni
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism; D000544:Alzheimer Disease / Q000378:metabolism*; D000704:Analysis of Variance; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000378:metabolism*; D042241:Early Diagnosis; D005260:Female; D005971:Glutamates / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D006179:Gyrus Cinguli / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D005971:Glutamates; D005973:Glutamine; D005680:gamma-Aminobutyric Acid
keywords: Aged; Alzheimer disease; Magnetic resonance spectroscopy; Mild cognitive impairment; Neurotransmitters