title: Modulation of the lipidomic profile due to a lipid challenge and fitness level: a postprandial study.
abstract: BACKGROUND
  The lipid composition of plasma is known to vary due to both phenotypic factors such as age, gender and BMI as well as with various diseases including cancer and neurological disorders. However, there is little investigation into the variation in the lipidome due to exercise and/ or metabolic challenges. The objectives of this present study were (i) To identify the glycerophospholipid, sphingolipids and ceramide changes in response to an oral lipid tolerance test (OLTT) in healthy adults and (ii) To identify the effect of aerobic fitness level on lipidomic profiles.
  
  
  METHODS
  214 healthy adults aged 18-60 years were recruited as part of a metabolic challenge study. A sub-group of 40 volunteers were selected for lipidomic analysis based on their aerobic fitness level. Ceramides, glycerophospholipids and sphingomyelins were quantified in baseline fasting plasma samples as well as at 60, 120, 180, 240 and 300 min following a lipid challenge using high-throughput flow injection ESI-MS/MS.
  
  
  RESULTS
  Mixed model repeated measures analysis identified lipids which were significantly changing over the time course of the lipid challenge. Included in these lipids were lysophosphoethanolamines (LPE), phosphoethanolamines (PE), phosphoglycerides (PG) and ceramides (Cer). Five lipids (LPE a C18:2, LPE a C18:1, PE aa C36:2, PE aa C36:3 and N-C16:1-Cer) had a fold change > 1.5 at 120 min following the challenge and these lipids remained elevated. Furthermore, three of these lipids (LPE a C18:2, PE aa C36:2 and PE aa C36:3) were predictive of fasting and peak plasma TAG concentrations following the OLTT. Further analysis revealed that fitness level has a significant impact on the response to the OLTT: in particular significant differences between fitness groups were observed for phosphatidylcholines (PC), sphingomyelins (SM) and ceramides.
  
  
  CONCLUSIONS
  This study identified specific lipids which were modulated by an acute lipid challenge. Furthermore, it identified a series of lipids which were modulated by fitness level. Future lipidomic studies should take into account environmental factors such as diet and fitness level during biomarker discovery work.
  
  
  BACKGROUND
  Data, clinicaltrials.gov, NCT01172951.
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.|UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: Morris
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.|UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Colm M
authors.initials: CM
authors.lastname: O'Grada
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Miriam F
authors.initials: MF
authors.lastname: Ryan
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gibney
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.|UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Roche
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Gibney
authors.affiliation: UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland. lorraine.brennan@ucd.ie.|UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland. lorraine.brennan@ucd.ie.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Brennan
mesh_terms: D000328:Adult; D003710:Demography; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D055442:Metabolome; D010713:Phosphatidylcholines; D010809:Physical Fitness; D019518:Postprandial Period
chemical_list: D008055:Lipids; D010713:Phosphatidylcholines