title: Decreased brain PME/PDE ratio in bipolar disorder: a preliminary (31) P magnetic resonance spectroscopy study.
abstract: OBJECTIVE
  The aim of the present study was to measure brain phosphorus-31 magnetic resonance spectroscopy ((31) P MRS) metabolite levels and the creatine kinase reaction forward rate constant (kf ) in subjects with bipolar disorder (BD).
  
  
  METHODS
  Subjects with bipolar euthymia (n = 14) or depression (n = 11) were recruited. Healthy comparison subjects (HC) (n = 23) were recruited and matched to subjects with BD on age, gender, and educational level. All studies were performed on a 3-Tesla clinical magnetic resonance imaging system using a (31) P/(1) H double-tuned volume head coil. (31) P spectra were acquired without (1) H-decoupling using magnetization-transfer image-selected in vivo spectroscopy. Metabolite ratios from a brain region that includes the frontal lobe, corpus callosum, thalamus, and occipital lobe are expressed as a percentage of the total phosphorus (TP) signal. Brain pH was also investigated.
  
  
  RESULTS
  Beta-nucleoside-triphosphate (β-NTP/TP) in subjects with bipolar depression was positively correlated with kf (p = 0.039, r(2) = 0.39); similar correlations were not observed in bipolar euthymia or HC. In addition, no differences in kf and brain pH were observed among the three diagnostic groups. A decrease in the ratio of phosphomonoesters to phosphodiesters (PME/PDE) was observed in subjects with bipolar depression relative to HC (p = 0.032). We also observed a trend toward an inverse correlation in bipolar depression characterized by decreased phosphocreatine and increased depression severity.
  
  
  CONCLUSIONS
  In our sample, kf was not altered in the euthymic or depressed mood state in BD. However, decreased PME/PDE in subjects with bipolar depression was consistent with differences in membrane turnover. These data provide preliminary support for alterations in phospholipid metabolism and mitochondrial function in bipolar depression.
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.|Department of Psychiatry, Salt Lake City, UT, USA.
authors.forename: Xian-Feng
authors.initials: XF
authors.lastname: Shi
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.|Department of Psychiatry, Salt Lake City, UT, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Carlson
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.|Department of Psychiatry, Salt Lake City, UT, USA.
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Sung
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.
authors.forename: Kristen K
authors.initials: KK
authors.lastname: Fiedler
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.
authors.forename: Lauren N
authors.initials: LN
authors.lastname: Forrest
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Hellem
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.
authors.forename: Rebekah S
authors.initials: RS
authors.lastname: Huber
authors.affiliation: Department of Radiology, University of Utah, Salt Lake City, UT, USA.
authors.forename: Seong-Eun
authors.initials: SE
authors.lastname: Kim
authors.affiliation: Brain Imaging Center, McLean Hospital, Belmont, MA, USA.|Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
authors.forename: Chun
authors.initials: C
authors.lastname: Zuo
authors.affiliation: Department of Radiology, University of Utah, Salt Lake City, UT, USA.|Department of Radiology, Korea University, Seoul, Korea.
authors.forename: Eun-Kee
authors.initials: EK
authors.lastname: Jeong
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.|Department of Psychiatry, Salt Lake City, UT, USA.|VISN 19 MIRECC, Salt Lake City Veterans Affairs Medical Center, Salt Lake City, UT, USA.
authors.forename: Perry F
authors.initials: PF
authors.lastname: Renshaw
authors.affiliation: The Brain Institute, Salt Lake City, UT, USA.|Department of Psychiatry, Salt Lake City, UT, USA.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Kondo
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000378:metabolism / Q000523:psychology; D003337:Corpus Callosum / Q000378:metabolism*; D003863:Depression / Q000175:diagnosis / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D010759:Phosphorus Isotopes / Q000494:pharmacology; D011569:Psychiatric Status Rating Scales; D013788:Thalamus / Q000378:metabolism*
chemical_list: D010743:Phospholipids; D010759:Phosphorus Isotopes; D010725:Phosphocreatine
keywords: 31P MRS; bipolar disorder; magnetization transfer