Decreased γ-aminobutyric acid levels in the parietal region of patients with Alzheimer's disease.

Abstract

PURPOSE:

To determine whether there are in vivo differences of γ-aminobutyric acid (GABA) levels in frontal and parietal regions of Alzheimer's disease (AD) patients, compared with healthy controls using magnetic resonance spectroscopy ((1) H-MRS).

MATERIALS AND METHODS:

Fifteen AD patients and fifteen age- and gender-matched healthy controls underwent (1) H-MRS of the frontal and parietal lobes using the "MEGA-Point Resolved Spectroscopy Sequence" (MEGA-PRESS) technique, and cognitive levels of subjects were evaluated using Mini-Mental State Examination (MMSE) tests. MRS data were processed using the Gannet program. Because the signal detected by MEGA-PRESS includes contributions from GABA, macromolecules and homocarnosine, it is labeled as "GABA+" rather than GABA. Differences of GABA+/Cr ratios between AD patients and controls were tested using covariance analysis, adjusting for gray matter fraction. The relationship between GABA+/Cr and MMSE scores was also analyzed.

RESULTS:

Significant lower GABA+/Cr ratios were found in the parietal region of AD patients compared with controls (P = 0.041). In AD patients, no significant correlations between GABA+/Cr and MMSE scores were found in either the frontal (r = -0.164; P = 0.558) or parietal regions (r = 0.025; P = 0.929).

CONCLUSION:

Decreased GABA+/Cr levels were present in the parietal region of patients with AD in vivo, suggesting that abnormalities of the GABAergic system may be present in the pathogenesis of AD.

• Authors: Xue Bai, Richard A E Edden, Fei Gao, Guangbin Wang, Lebin Wu, Bin Zhao, Minzhong Wang, Queenie Chan, Weibo Chen, Peter B Barker
• Journal: Journal of magnetic resonance imaging : JMRI (J Magn Reson Imaging) Vol. 41 Issue 5 Pg. 1326-31 (May 2015) ISSN: 1522-2586 [Electronic] United States
• PMID: 24863149 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 Wiley Periodicals, Inc.

Chemical References

• Biomarkers
• gamma-Aminobutyric Acid

Topics

• Aged
• Alzheimer Disease (metabolism)
• Biomarkers (metabolism)
• Down-Regulation
• Female
• Frontal Lobe (metabolism)
• Humans
• Magnetic Resonance Imaging (methods)
• Male
• Middle Aged
• Molecular Imaging (methods)
• Parietal Lobe (metabolism)
• Proton Magnetic Resonance Spectroscopy (methods)
• Tissue Distribution
• gamma-Aminobutyric Acid (metabolism)