title: Short-term administration of uridine increases brain membrane phospholipid precursors in healthy adults: a 31-phosphorus magnetic resonance spectroscopy study at 4T.
abstract: OBJECTIVE
  Altered metabolism of membrane phospholipids has been implicated in bipolar disorder. In humans, uridine is an important precursor of cytidine diphosphate (CDP)-choline, which plays a critical role in phospholipid synthesis and is currently being evaluated as a potential treatment for bipolar depression.
  
  
  METHODS
  A total of 17 healthy males (mean age ± SD: 32.73 ± 7.2 years; range: 21.8-46.4 years) were enrolled in this study. Subjects underwent a 31-phosphorus magnetic resonance spectroscopy ((31) P-MRS) acquisition at baseline and then again after seven days of either 2 g of uridine or placebo administration. A two-dimensional chemical shift imaging (31) P-MRS acquisition collected spectral data from a 4 × 4 cluster of voxels acquired in the axial plane encompassing the subcortical structures as well as frontal-temporal cortical gray and white matter. The slab thickness was 3 cm and the approximate total volume of brain sampled was 432 cm(3) . The spectra obtained were analyzed using a fully automated in-house fitting algorithm. A population-averaged generalized estimating equation was used to evaluate changes both in phosphomonoesters (PME) [phosphocholine (PCho) and phosphoethanolamine (PEtn)] and phosphodiesters (PDE) [glycerophosphocholine (GPCho) and glycerophosphethanolamine (GPEtn)]. Metabolite ratios were reported with respect to the total integrated (31) P resonance area.
  
  
  RESULTS
  The uridine group had significantly increased total PME and PEtn levels over the one-week period [6.32 and 7.17% for PME and PEtn, respectively (p<0.001)]. Other metabolite levels such as PCho, PDE, GPEtn and GPCho showed no significant changes following either uridine or placebo (all p>0.05).
  
  
  CONCLUSIONS
  This is the first study to report a direct effect of uridine on membrane phospholipid precursors in healthy adults using (31) P-MRS. Sustained administration of uridine appears to increase PME in healthy subjects. Further investigation is required to clarify the effects of uridine in disorders with altered phospholipid metabolism such as bipolar disorder.
authors.affiliation: The Brain Institute, University of Utah, 383 Colorow Drive, Salt Lake City, UT 84102, USA. niv_aga@yahoo.co.uk
authors.forename: Nivedita
authors.initials: N
authors.lastname: Agarwal
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Sung
authors.forename: J Eric
authors.initials: JE
authors.lastname: Jensen
authors.forename: Grace
authors.initials: G
authors.lastname: daCunha
authors.forename: David
authors.initials: D
authors.lastname: Harper
authors.forename: David
authors.initials: D
authors.lastname: Olson
authors.forename: Perry F
authors.initials: PF
authors.lastname: Renshaw
mesh_terms: D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003566:Cytidine Diphosphate Choline / Q000494:pharmacology*; D004983:Ethanolamines / Q000378:metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D010759:Phosphorus Isotopes; D010767:Phosphorylcholine / Q000378:metabolism; D013997:Time Factors; D014529:Uridine / Q000494:pharmacology*
chemical_list: D004983:Ethanolamines; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D010759:Phosphorus Isotopes; D010767:Phosphorylcholine; C002449:glycerophosphoethanolamine; D003566:Cytidine Diphosphate Choline; C005448:phosphorylethanolamine; D014529:Uridine