title: L(+) and D(-) lactate are increased in plasma and urine samples of type 2 diabetes as measured by a simultaneous quantification of L(+) and D(-) lactate by reversed-phase liquid chromatography tandem mass spectrometry.
abstract: BACKGROUND
  Plasma and urinary levels of D-lactate have been linked to the presence of diabetes. Previously developed techniques have shown several limitations to further evaluate D-lactate as a biomarker for this condition.
  
  
  METHODS
  D- and L-lactate were quantified using ultraperformance liquid chromatography tandem mass spectrometry with labelled internal standard. Samples were derivatized with diacetyl-L-tartaric anhydride and separated on a C(18)-reversed phase column. D- and L-lactate were analysed in plasma and urine of controls, patients with inflammatory bowel disease (IBD), and patients with type 2 diabetes (T2DM).
  
  
  RESULTS
  Quantitative analysis of D- and L-lactate was achieved successfully. Calibration curves were linear (r(2) > 0.99) over the physiological and pathophysiological ranges. Recoveries for urine and plasma were between 96% and 113%. Inter- and intra-assay variations were between 2% and 9%. The limits of detection of D-lactate and L-lactate in plasma were 0.7 μmol/L and 0.2 μmol/L, respectively. The limits of detection of D-lactate and L-lactate in urine were 8.1 nmol/mmol creatinine and 4.4 nmol/mmol creatinine, respectively. Plasma and urinary levels of D- and L-lactate were increased in patients with IBD and T2DM as compared with controls.
  
  
  CONCLUSIONS
  The presented method proved to be suitable for the quantification of D- and L-lactate and opens the possibility to explore the use of D-lactate as a biomarker.
authors.affiliation: Laboratory for Metabolism and Vascular Medicine, Department of Internal Medicine, Maastricht University, P. Debeyelaan 25, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. j.scheijen@maastrichtuniversity.nl
authors.forename: Jean L J M
authors.initials: JL
authors.lastname: Scheijen
authors.forename: Nordin M J
authors.initials: NM
authors.lastname: Hanssen
authors.forename: Marjo P H
authors.initials: MP
authors.lastname: van de Waarenburg
authors.forename: Daisy M A E
authors.initials: DM
authors.lastname: Jonkers
authors.forename: Coen D A
authors.initials: CD
authors.lastname: Stehouwer
authors.forename: Casper G
authors.initials: CG
authors.lastname: Schalkwijk
mesh_terms: D000328:Adult; D000368:Aged; D056148:Chromatography, Reverse-Phase; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism* / Q000652:urine; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood / Q000652:urine; D019344:Lactic Acid / Q000097:blood / Q000378:metabolism* / Q000652:urine; D008297:Male; D008875:Middle Aged; D053719:Tandem Mass Spectrometry
chemical_list: D019344:Lactic Acid