title: Analysis of urinary methylated nucleosides of patients with coronary artery disease by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.
abstract: BACKGROUND
  In recent years, methylated nucleosides have been considered to be potential biomarkers to human diseases. The early diagnosis of coronary artery disease (CAD) is an unsolved problem in clinical cardiology. The aim of our study is to evaluate whether urinary methylated nucleosides can serve as useful biomarkers for CAD.
  
  
  METHODS
  A solid-phase extraction (SPE) column was used for extraction and purification of methylated nucleosides in urine, and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) was employed for specific, sensitive and rapid determination of the urinary methylated nucleosides from patients with cardiac events.
  
  
  RESULTS
  We have analyzed six methylated nucleosides (N(3)-methylcytidine, N(1)-methyladenosine, N(6)-methyladenosine, N(2)-methylguanosine, N(1)-methylguanosine and N(2),N(2)-dimethylguanosine) in urine from 51 patients with CAD and 25 non-CAD controls by HPLC/ESI-MS/MS using selective reaction monitoring (SRM). Our results have shown that there were significant differences in the N(6)-methyladenosine levels from the patients and the non-CAD controls in the urine analyzed.
  
  
  CONCLUSIONS
  The results have indicated that HPLC/ESI-MS/MS is a highly specific and sensitive tool to measure urinary methylated nucleosides for analysis of CAD. Our result has revealed that the evaluation of urinary methylated nucleosides might be helpful in the analysis of CAD by liquid chromatography/mass spectrometry. Therefore, this N(6)-methyladenosine is worthy of further studies in the near future.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
authors.forename: Yanru
authors.initials: Y
authors.lastname: Li
authors.forename: Haiyi
authors.initials: H
authors.lastname: Yu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Xinye
authors.initials: X
authors.lastname: Xu
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhou
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.forename: Gu
authors.initials: G
authors.lastname: Yuan
mesh_terms: D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003324:Coronary Artery Disease / Q000652:urine*; D006801:Humans; D008745:Methylation; D009705:Nucleosides / Q000652:urine*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D009705:Nucleosides