title: Reduced Insular Glutamine and N-acetylaspartate in systemic lupus erythematosus: a single-voxel (1)H-MR spectroscopy study.
abstract: OBJECTIVE
  To investigate for differences in metabolic concentrations and ratios between patients with systemic lupus erythematosus (SLE) without (group SLE) and those with neurological symptoms (group NPSLE) compared to a healthy control (group HC) in three normal-appearing brain regions: the frontal white matter, right insula (RI), and occipital gray matter and whether changes in any of the metabolites or metabolic ratios are correlated to disease activity and other clinical parameters.
  
  
  METHODS
  Twenty patients with SLE (18 women and 2 men, age range 23.4-64.6 years, mean age 43.9 years), 23 NPSLE patients (23 women, age range 23.7-69.8 years, mean age 42.4 years), and 21 HC (19 women and 2 men, age range 21.0-65.7 years, mean age 43.4 years) were included. All subjects had conventional brain magnetic resonance imaging and (1)H single-voxel spectroscopy, clinical assessment, and laboratory testing.
  
  
  RESULTS
  NPSLE patients had significantly reduced N-acetylaspartate (NAA)/creatine compared to HC (P = .02) and SLE patients (P = .01) in the RI. Lower glutamine/creatine levels were also detected in RI in both patient groups and in frontal white matter in NPSLE patients compared to HC (P = .01, P = .02). NAA/Cr ratio in the RI was significantly negatively correlated with the Systemic Lupus Erythematosus Disease Activity Index (r = -0.41; P = .008), and patients with active SLE symptoms also had a trend toward lower NAA/creatine ratios (1.02 vs 1.12; P = .07).
  
  
  CONCLUSIONS
  The present data support previous findings of abnormal metabolic changes in normal-appearing regions in the brain of both SLE and NPSLE patients and raise the possibility that especially NAA, glutamine, and glutamate may be additional biomarkers for cerebral disease activity in SLE patients as these early metabolic changes occur in the brain of SLE patients before neurologic and imaging manifestations become apparent.
authors.affiliation: Department of Internal Medicine, University of Michigan Health Systems, Ann Arbor, MI.
authors.forename: Patricia
authors.initials: P
authors.lastname: Cagnoli
authors.forename: Richard E
authors.initials: RE
authors.lastname: Harris
authors.forename: Dan
authors.initials: D
authors.lastname: Frechtling
authors.forename: George
authors.initials: G
authors.lastname: Berkis
authors.forename: Richard H
authors.initials: RH
authors.lastname: Gracley
authors.forename: Courtney C
authors.initials: CC
authors.lastname: Graft
authors.forename: Suzan E
authors.initials: SE
authors.lastname: Lowe
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Chenevert
authors.forename: William J
authors.initials: WJ
authors.lastname: McCune
authors.forename: Stephen
authors.initials: S
authors.lastname: Gebarski
authors.forename: Pia C
authors.initials: PC
authors.lastname: Sundgren
mesh_terms: D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D005260:Female; D005973:Glutamine / Q000378:metabolism*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011522:Protons; D005973:Glutamine; D001224:Aspartic Acid; C000179:N-acetylaspartate
keywords: MRI; MRS; NSPLE; SLE; metabolites
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