title: Tissue-specific differences in brain phosphodiesters in late-life major depression.
abstract: OBJECTIVE
  Late-life depression has been hypothesized to have a neurodegenerative component that leads to impaired executive function and increases in subcortical white matter hyperintensities. Phosphorus magnetic resonance spectroscopy (MRS) can quantify several important phosphorus metabolites in the brain, particularly the anabolic precursors and catabolic metabolites of the constituents of cell membranes, which could be altered by neurodegenerative activity.
  
  
  METHODS
  Ten patients with late-life major depression who were medication free at time of study and 11 aged normal comparison subjects were studied using (31)P MRS three-dimensional chemical shift imaging at 4 Tesla. Phosphatidylcholine and phosphatidylethanolamine comprise 90% of cell membranes in brain but cannot be quantified precisely with (31)P MRS. We measured phosphocholine and phosphoethanolamine, which are anabolic precursors, as well as glycerophosphocholine and glycerophosphoethanolamine, which are catabolic metabolites of phosphatidylcholine and phosphatidylethanolamine.
  
  
  RESULTS
  In accordance with our hypotheses, glycerophosphoethanolamine was elevated in white matter of depressed subjects, suggesting enhanced breakdown of cell membranes in these subjects. Glycerophosphocholine did not show any significant difference between comparison and depressed subjects but both showed an enhancement in white matter compared with gray matter. Contrary to our hypotheses, neither phosphocholine nor phosphoethanolamine showed evidence for reduction in late-life depression.
  
  
  CONCLUSIONS
  These findings support the hypothesis that neurodegenerative processes occur in white matter in patients with late-life depression more than in the normal elderly population.
authors.affiliation: Geriatric Psychiatry Program, McLean Hospital, Belmont, MA; Department of Psychiatry, Harvard Medical School, Boston, MA. Electronic address: dharper@mclean.harvard.edu.
authors.forename: David G
authors.initials: DG
authors.lastname: Harper
authors.affiliation: Neuroimaging Center, McLean Hospital, Belmont, MA; Department of Psychiatry, Harvard Medical School, Boston, MA.
authors.forename: J Eric
authors.initials: JE
authors.lastname: Jensen
authors.affiliation: Laboratory for Psychiatric Biostatistics, McLean Hospital, Belmont, MA; Department of Psychiatry, Harvard Medical School, Boston, MA.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Ravichandran
authors.affiliation: Department of Psychiatry, Uludag University Faculty of Medicine, Bursa, Turkey.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Sivrioglu
authors.affiliation: Neuroimaging Center, McLean Hospital, Belmont, MA; Department of Psychiatry, Harvard Medical School, Boston, MA.
authors.forename: Marisa
authors.initials: M
authors.lastname: Silveri
authors.affiliation: Department of Psychiatry, Harvard Medical School, Boston, MA; Department of Psychiatry, Massachusetts General Hospital, Boston, MA.
authors.forename: Dan V
authors.initials: DV
authors.lastname: Iosifescu
authors.affiliation: The Brain Institute, University of Utah, Salt Lake City, UT.
authors.forename: Perry F
authors.initials: PF
authors.lastname: Renshaw
authors.affiliation: Geriatric Psychiatry Program, McLean Hospital, Belmont, MA; Department of Psychiatry, Harvard Medical School, Boston, MA.
authors.forename: Brent P
authors.initials: BP
authors.lastname: Forester
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D001921:Brain / Q000378:metabolism*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000378:metabolism*; D004983:Ethanolamines / Q000378:metabolism; D005260:Female; D005997:Glycerylphosphorylcholine / Q000378:metabolism; D066128:Gray Matter / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010767:Phosphorylcholine / Q000378:metabolism; D066127:White Matter / Q000378:metabolism*
chemical_list: D004983:Ethanolamines; D009943:Organophosphorus Compounds; D010714:Phosphatidylethanolamines; D010767:Phosphorylcholine; C002449:glycerophosphoethanolamine; D005997:Glycerylphosphorylcholine; C005448:phosphorylethanolamine
keywords: (31)P MRS; MRSI; aging; elderly; membranes