title: High-throughput quantitative profiling of serum N-glycome by MALDI-TOF mass spectrometry and N-glycomic fingerprint of liver fibrosis.
abstract: BACKGROUND
  The use of MALDI-TOF mass spectrometry (MS) in quantitative glycan profiling has not been reported. In this study, we attempted to establish a high-throughput quantitative assay for profiling serum N-glycome, and we applied the new assay to identifying serum N-glycans for diagnosis of liver fibrosis and cirrhosis.
  
  
  METHODS
  N-glycans from whole serum proteins in 2 microL serum were released by enzymatic digestion, cleaned up by hydrophilic chromatography, and subsequently quantitatively profiled with a linear MALDI-TOF MS system, which was originally designed for quantitative proteomic profiling. Serum N-glycome profiles from 46 patients with chronic hepatitis B infection and with different degrees of liver fibrosis were examined.
  
  
  RESULTS
  The intra- and interassay CVs of peak intensities of the standard N-glycans were <8% and <17%, respectively. When the assay was applied to the analysis of serum N-glycome profiles, 17 peaks were found to be potential biomarkers for detection of liver fibrosis/cirrhosis. Linear regression analysis revealed that 4 peaks of 1341.5, 1829.7, 1933.3, and 2130.3 m/z (all P <0.005) had complementary value in detecting liver fibrosis and included them, but not any serological markers, in the diagnostic model. Leave-one-out cross-validation showed the diagnostic model could identify significant fibrosis (Ishak score > or = 3) and cirrhosis (Ishak score > or = 5), both at 85% accuracy.
  
  
  CONCLUSIONS
  This is the first study to illustrate the quantitative aspect of MALDI-TOF MS in N-glycome profiling and the first study to reveal the potential value of the serum N-glycan profile for identifying liver fibrosis.
authors.affiliation: Li Ka Shing Institute of Health Sciences, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR.
authors.forename: Richard K T
authors.initials: RK
authors.lastname: Kam
authors.forename: Terence C W
authors.initials: TC
authors.lastname: Poon
authors.forename: Henry L Y
authors.initials: HL
authors.lastname: Chan
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wong
authors.forename: Alex Y
authors.initials: AY
authors.lastname: Hui
authors.forename: Joseph J Y
authors.initials: JJ
authors.lastname: Sung
mesh_terms: D015415:Biomarkers / Q000097:blood; D005240:Feasibility Studies; D005260:Female; D019698:Hepatitis C, Chronic / Q000150:complications; D006801:Humans; D016014:Linear Models; D008103:Liver Cirrhosis / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides / Q000097:blood*; D040081:Protein Array Analysis / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D044967:Serum; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D011134:Polysaccharides