title: Fasting serum lipid and dehydroepiandrosterone sulfate as important metabolites for detecting isolated postchallenge diabetes: serum metabolomics via ultra-high-performance LC-MS.
abstract: BACKGROUND
  Isolated postchallenge diabetes (IPD), a subtype of type 2 diabetes mellitus (T2DM) defined as 2-h postprandial plasma glucose ≥ 200 mg/dL (≥ 11.1 mmol/L) and fasting plasma glucose (FPG) <108 mg/dL (<6.0 mmol/L), is often overlooked during screening for diabetes on the basis of FPG concentrations. A key challenge is early identification of IPD by the use of fasting serum, which is critical for large-scale diabetes screening.
  
  
  METHODS
  We applied a nontargeted metabolomic approach using ultra-high-performance liquid chromatography-quadrupole TOF-mass spectrometry (UPLC-QTOF-MS) to analyze serum samples from 51 patients with IPD, 52 with newly diagnosed T2DM, and 49 healthy individuals. We processed metabolite profiles by multivariate analysis to identify potential metabolites, which were further confirmed by tandem MS (MS/MS). We also used GC-MS and ELISA methods to detect potentially important metabolites. A number of independent samples were selected to validate the identified candidates.
  
  
  RESULTS
  We selected 15 metabolites with a view to distinguishing patients with IPD, whereas 11 were identified with an authentic standard. The selected metabolites included linoleic acid, oleic acid, phospholipids, and dehydroepiandrosterone sulfate (DHEA-S). In IPD samples, significantly higher linoleic and oleic acid (P < 0.001) and lower DHEA-S (P < 0.001) concentrations were observed, compared with controls. The area under the curve from a combination of linoleic acid, oleic acid, and DHEA-S in the validation study was 0.849 for the IPD group.
  
  
  CONCLUSIONS
  The current study provides useful information to bridge the gaps in our understanding of the metabolic alterations associated with IPD and might facilitate the characterization of patients with IPD by the use of fasting serum.
authors.affiliation: Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin, P R China.
authors.forename: Liyan
authors.initials: L
authors.lastname: Liu
authors.forename: Maoqing
authors.initials: M
authors.lastname: Wang
authors.forename: Xue
authors.initials: X
authors.lastname: Yang
authors.forename: Mingxin
authors.initials: M
authors.lastname: Bi
authors.forename: Lixin
authors.initials: L
authors.lastname: Na
authors.forename: Yucun
authors.initials: Y
authors.lastname: Niu
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Changhao
authors.initials: C
authors.lastname: Sun
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood* / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000175:diagnosis / Q000378:metabolism; D005215:Fasting / Q000097:blood*; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood*; D008297:Male; D055442:Metabolome; D055432:Metabolomics / Q000379:methods; D008875:Middle Aged; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D008055:Lipids; D019314:Dehydroepiandrosterone Sulfate