title: Plasma asymmetric dimethylarginine (ADMA), nitrate and the indices of low-density lipoprotein oxidation.
abstract: BACKGROUND
  Oxidative modification of low-density lipoprotein (LDL) is an important contributor to atherosclerosis. Also, oxidized LDL is suspected to cause accumulation of asymmetric dimethylarginine (ADMA), an endogenous competitive nitric oxide synthase inhibitor, which is suggested to be an independent risk factor for atherosclerosis. This study was performed to evaluate how plasma ADMA is related to plasma nitric oxide production, oxidized LDL and ex vivo susceptibility of LDL to oxidation in mildly hypercholesterolemic otherwise healthy subjects.
  
  
  METHODS
  Plasma ADMA was determined using high performance liquid chromatography tandem mass spectrometry. LDL oxidation was estimated by the lag time and rate of copper-induced LDL oxidation. The nitric oxide production in plasma was estimated based on nitrate (NO(3)(-)) determination and plasma oxidized LDL was determined by a capture ELISA.
  
  
  RESULTS
  Low ADMA was a significant determinant for high LDL oxidation rate and concentration of plasma ADMA was associated with nitrate levels.
  
  
  CONCLUSIONS
  There may be an interplay between LDL fatty acid oxidation rate and plasma ADMA and nitrate. We hypothesize that plasma ADMA has a bivalent role: high ADMA may have a protective role in decelerating LDL fatty acid oxidation and also a risk factor for endothelial dysfunction by decreasing availability of nitric oxide.
authors.affiliation: Department of Internal Medicine, University Hospital of Tampere, Tampere, Finland. hannu.paiva@uta.fi <hannu.paiva@uta.fi>
authors.forename: Hannu
authors.initials: H
authors.lastname: Päivä
authors.forename: Juha
authors.initials: J
authors.lastname: Laakso
authors.forename: Inkeri
authors.initials: I
authors.lastname: Ruokonen
authors.forename: Mari
authors.initials: M
authors.lastname: Luomala
authors.forename: Marika
authors.initials: M
authors.lastname: Saarela
authors.forename: Tiina
authors.initials: T
authors.lastname: Solakivi
authors.forename: Saara
authors.initials: S
authors.lastname: Metso
authors.forename: Matti
authors.initials: M
authors.lastname: Nikkilä
authors.forename: Erkki
authors.initials: E
authors.lastname: Wuolijoki
authors.forename: Reijo
authors.initials: R
authors.lastname: Laaksonen
authors.forename: Terho
authors.initials: T
authors.lastname: Lehtimäki
mesh_terms: D000328:Adult; D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D050197:Atherosclerosis / Q000097:blood / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D050356:Lipid Metabolism / Q000502:physiology; D015227:Lipid Peroxidation / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009566:Nitrates / Q000097:blood*; D009569:Nitric Oxide / Q000097:blood; D012307:Risk Factors
chemical_list: D008077:Lipoproteins, LDL; D009566:Nitrates; C099252:oxidized low density lipoprotein; D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D001120:Arginine