title: Serum proteomic changes after randomized prolonged erythropoietin treatment and/or endurance training: detection of novel biomarkers.
abstract: BACKGROUND
  Despite implementation of the biological passport to detect erythropoietin abuse, a need for additional biomarkers remains. We used a proteomic approach to identify novel serum biomarkers of prolonged erythropoiesis-stimulating agent (ESA) exposure (Darbepoietin-α) and/or aerobic training.
  
  
  METHODS
  Thirty-six healthy young males were randomly assigned to the following groups: Sedentary-placebo (n = 9), Sedentary-ESA (n = 9), Training-placebo (n = 10), or Training-ESA (n = 8). They were treated with placebo/Darbepoietin-α subcutaneously once/week for 10 weeks followed by a 3-week washout period. Training consisted of supervised biking 3/week for 13 weeks at the highest possible intensity. Serum was collected at baseline, week 3 (high dose Darbepoietin-α), week 10 (reduced dose Darbepoietin-α), and after a 3-week washout period.
  
  
  METHODS
  Serum proteins were separated according to charge and molecular mass (2D-gel electrophoresis). The identity of proteins from spots exhibiting altered intensity was determined by mass spectrometry.
  
  
  RESULTS
  Six protein spots changed in response to Darbepoietin-α treatment. Comparing all 4 experimental groups, two protein spots (serotransferrin and haptoglobin/haptoglobin related protein) showed a significant response to Darbepoietin-α treatment. The haptoglobin/haptoglobin related protein spot showed a significantly lower intensity in all subjects in the training-ESA group during the treatment period and increased during the washout period.
  
  
  CONCLUSIONS
  An isoform of haptoglobin/haptoglobin related protein could be a new anti-doping marker and merits further research.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01320449.
authors: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark; Medical Research Laboratories, Aarhus University, Aarhus, Denmark; Research Laboratory for Biochemical Pathology, Institute for Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors: Britt
authors: B
authors: Christensen
authors: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors: Maja
authors: M
authors: Ludvigsen
authors: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark; Medical Research Laboratories, Aarhus University, Aarhus, Denmark.
authors: Birgitte
authors: B
authors: Nellemann
authors: Edison Biotechnology Institute Ohio University, Athens, Ohio, United States of America; Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America.
authors: John J
authors: JJ
authors: Kopchick
authors: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors: Bent
authors: B
authors: Honoré
authors: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors: Jens Otto L
authors: JO
authors: Jørgensen
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins; D002853:Chromatography, Liquid; D000068256:Darbepoetin alfa / Q000627:therapeutic use; D015180:Electrophoresis, Gel, Two-Dimensional; D004909:Erythrocyte Indices; D004921:Erythropoietin / Q000627:therapeutic use*; D006242:Haptoglobins; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance; D020543:Proteome; D040901:Proteomics; D053719:Tandem Mass Spectrometry; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D006242:Haptoglobins; D020543:Proteome; D004921:Erythropoietin; D000068256:Darbepoetin alfa