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Open Access 01-12-2014 | Research

Hippocampal glutamate-glutamine (Glx) in adults with Down syndrome: a preliminary study using in vivo proton magnetic resonance spectroscopy (¹H MRS)

Authors: Giles MY Tan, Felix Beacher, Eileen Daly, Jamie Horder, Verinder Prasher, Maria-Luisa Hanney, Robin Morris, Simon Lovestone, Kieran C Murphy, Andrew Simmons, Declan GM Murphy

Published in: Journal of Neurodevelopmental Disorders | Issue 1/2014

Abstract

Background

Down syndrome (DS), or trisomy 21, is one of the most common autosomal mutations. People with DS have intellectual disability (ID) and are at significantly increased risk of developing Alzheimer’s disease (AD). The biological associates of both ID and AD in DS are poorly understood, but glutamate has been proposed to play a key role. In non-DS populations, glutamate is essential to learning and memory and glutamate-mediated excitotoxicity has been implicated in AD. However, the concentration of hippocampal glutamate in DS individuals with and without dementia has not previously been directly investigated. Proton magnetic resonance spectroscopy (¹H MRS) can be used to measure in vivo the concentrations of glutamate-glutamine (Glx). The objective of the current study was to examine the hippocampal Glx concentration in non-demented DS (DS-) and demented DS (DS+) individuals.

Methods

We examined 46 adults with DS (35 without dementia and 11 with dementia) and 39 healthy controls (HC) using ¹H MRS and measured their hippocampal Glx concentrations.

Results

There was no significant difference in the hippocampal Glx concentration between DS+ and DS-, or between either of the DS groups and the healthy controls. Also, within DS, there was no significant correlation between hippocampal Glx concentration and measures of overall cognitive ability. Last, a sample size calculation based on the effect sizes from this study showed that it would have required 6,257 participants to provide 80% power to detect a significant difference between the groups which would indicate that there is a very low likelihood of a type 2 error accounting for the findings in this study.

Conclusions

Individuals with DS do not have clinically detectable differences in hippocampal Glx concentration. Other pathophysiological processes likely account for ID and AD in people with DS.

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Title: Hippocampal glutamate-glutamine (Glx) in adults with Down syndrome: a preliminary study using in vivo proton magnetic resonance spectroscopy (1H MRS)
Authors: Giles MY Tan
Felix Beacher
Eileen Daly
Jamie Horder
Verinder Prasher
Maria-Luisa Hanney
Robin Morris
Simon Lovestone
Kieran C Murphy
Andrew Simmons
Declan GM Murphy
Publication date: 01-12-2014
Publisher: BioMed Central
Published in: Journal of Neurodevelopmental Disorders / Issue 1/2014
Print ISSN: 1866-1947
Electronic ISSN: 1866-1955
DOI: https://doi.org/10.1186/1866-1955-6-42

At a glance: The STEP trials

Springer Medicine

Hippocampal glutamate-glutamine (Glx) in adults with Down syndrome: a preliminary study using in vivo proton magnetic resonance spectroscopy (¹H MRS)

Abstract

Background

Methods

Results

Conclusions

At a glance: The STEP trials

Springer Medicine

Abstract

Background

Methods

Results

Conclusions

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