Dear Mrs. Hubbers,
I am trying to find literature on observed associations among metabolite levels, for example, correlations between NAA and glutamate levels, within the same sample of individuals.
I find that in most applied 1h-mrs papers, a single or multiple metabolites are spotlighted and subject to univariate statistical tests (to evaluate associations with other variables, for example, symptoms of a disorder), but few papers report or statistically account for (e.g., via multiple regression) associations among metabolites. Some papers do report such associations (though typically between a pair or a few pairs of metabolites only), however, these results are buried because they are not the focus of the paper.
As such, I’m hoping others will know of papers within their applied fields of studies that have reported associations among metabolites within the same sample, and will be kind enough to share citations of such papers here.
Thanks in advance, and please tell a friend,
p.s., I think there should be an applied section of the forum.
Thanks for the great suggestion of a sub-forum for users with a primary interest in applying the mysterious art that is MRS. I think I can add a category like that.
I agree that between-metabolite association analysis is frequently a secondary or even tertiary analysis in most papers, and frequently treated as an exploratory goal. Are you looking for a particular cohort or particular metabolites? Are correlations across groups (i.e. in clinical studies) valuable too? I wonder whether there are appropriate search terms you could use - maybe even a bunch of very explicit phrases like “NAA was positively correlated with Cho” or “metabolite level cross-correlations”… I can imagine there are so many ways to phrase this that it’ll be hard to find everything.
This is going to be super-selective and probably not very helpful, but here are a few references that I’ve contributed to:
Region-specific elevations of glutamate + glutamine correlate with the sensory symptoms of autism spectrum disorders - PubMed (GABA vs Glx)
Neurometabolites and associations with cognitive deficits in mild cognitive impairment: a magnetic resonance spectroscopy study at 7 Tesla - PubMed (a bunch of stuff vs tNAA)
Low visual cortex GABA levels in hepatic encephalopathy: links to blood ammonia, critical flicker frequency, and brain osmolytes - PubMed (GABA vs mI vs Gln vs Glu)
Speak soon hopefully
To answer your questions: ideally, the cohort would be healthy controls. failing that, the cohort could be anything (to your “clinical studies” point). I am interested in correlations between any pairs of metabolites, the more the merrier.
I tried my best to search for articles on metabolite-metabolite associations (as Richard calls them), but any terms I can generate produce thousands of hits, none of which focus on metabolite-metabolite associations (though many may include them as secondary or tertiary findings, as you suggested).
Thanks for the refs! I wish I could join you at the upcoming MRS thing, but alas, November’s GABAganza is all I can manage ;D