title: Brain glutamate in anorexia nervosa: a magnetic resonance spectroscopy case control study at 7 Tesla.
abstract: Anorexia nervosa (AN) is a serious psychiatric disorder with high morbidity and mortality. There are no established pharmacological treatments and the neurobiology of the condition is poorly understood. Previous studies using magnetic resonance spectroscopy (MRS) have shown that AN may be associated with reductions in indices of brain glutamate; however, at conventional field strengths (≤3 T), it is difficult to separate glutamate from its precursor and metabolite, glutamine.
  
  
  
  The objective of the present study was to use high field (7 T) MRS to measure concentrations of glutamate, in three separate brain voxels, in women with AN.
  
  
  
  We studied 13 female participants with AN and 12 healthy female controls who underwent MRS scanning at 7 T with voxels placed in anterior cingulate cortex, occipital cortex and putamen. Neurometabolites were calculated using the unsuppressed water signal as a reference and corrected for individual cerebrospinal fluid concentration in the voxel.
  
  
  
  We found that participants with AN had significantly lower concentrations of glutamate in all three voxels (mean reduction 8%, p = 0.002) but glutamine levels were not altered. Concentrations of N-acetylaspartate, creatine, GABA and glutathione were also unchanged. However, inositol was lower in AN participants in anterior cingulate (p = 0.022) and occipital cortex (p = 0.002).
  
  
  
  Women with AN apparently have widespread reductions in brain glutamate. Further work will be needed to assess if this change has pathophysiological relevance or whether it is a consequence of the many physical changes produced in AN by food restriction.
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK.
authors.forename: Beata R
authors.initials: BR
authors.lastname: Godlewska
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Pike
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK.
authors.forename: Ann L
authors.initials: AL
authors.lastname: Sharpley
authors.affiliation: Oxford Health NHS Foundation Trust, Oxford, OX1 7JX, UK.
authors.forename: Agnes
authors.initials: A
authors.lastname: Ayton
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK.|Oxford Health NHS Foundation Trust, Oxford, OX1 7JX, UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Park
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK. phil.cowen@psych.ox.ac.uk.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Cowen
authors.affiliation: Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
authors.forename: Uzay E
authors.initials: UE
authors.lastname: Emir
mesh_terms: D000293:Adolescent; D000328:Adult; D000856:Anorexia Nervosa / Q000000981:diagnostic imaging / Q000378:metabolism*; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D016022:Case-Control Studies; D003401:Creatine / Q000378:metabolism; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D006179:Gyrus Cinguli / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D007294:Inositol / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D009778:Occipital Lobe / Q000000981:diagnostic imaging / Q000378:metabolism; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; D005680:gamma-Aminobutyric Acid; C000179:N-acetylaspartate; D003401:Creatine
keywords: Anorexia nervosa; Glutamate; Glutamine; Magnetic resonance spectroscopy