title: Short-term manipulation of plasma free fatty acids does not change skeletal muscle concentrations of ceramide and glucosylceramide in lean and overweight subjects.
abstract: BACKGROUND
  Increased plasma free fatty acid (FFA) concentrations may be in part responsible for the increased levels of ceramide in skeletal muscle of obese subjects.
  
  
  OBJECTIVE
  We studied the effect of lowering and increasing plasma FFA levels on muscle ceramide and glucosylceramide concentrations in lean and obese subjects.
  
  
  METHODS
  Plasma FFAs were either increased or decreased for 6 h by infusing a lipid emulsion or using Acipimox, respectively. Muscle biopsies were performed before and after the intervention for measurements of ceramide and glucosylceramide.
  
  
  METHODS
  Eight lean [body mass index 21.9 (range, 19.6-24.6) kg/m2] and six overweight/obese [body mass index 34.4 (27.8-42.5) kg/m2] subjects without type 2 diabetes mellitus participated in the study.
  
  
  METHODS
  Differences in muscle ceramide and glucosylceramide upon manipulation of plasma FFAs were measured.
  
  
  RESULTS
  There were no differences in muscle ceramide and glucosylceramide between lean and obese subjects, respectively. Increasing or decreasing plasma FFAs for 6 h had no effect on ceramide [high FFAs: 24 (19-25) vs. 24 (22-27) pmol/mg muscle, P=0.46; and 22 (20-28) vs. 24 (18-26) pmol/mg muscle, P=0.89 in lean and obese, respectively; low FFAs: 26 (24-35) vs. 23 (18-27) pmol/mg muscle, P=0.17 and 24 (15-44) vs. 24 (19-42) pmol/mg muscle, P=0.6 in lean and obese, respectively] and glucosylceramide [high FFAs: 2.0 (1.7-4.3) vs. 3.4 (2.1-4.6) pmol/mg muscle, P=0.17; and 3.0 (1.3-6.7) vs. 2.6 (1.2-3.9) pmol/mg muscle, P=0.89 in lean and obese, respectively; low FFAs: 2.2 (1.0-4.4) vs. 1.7 (1.4-3.0) pmol/mg muscle, P=0.92; and 6.6 (1.0-25.0) vs. 4.3 (1.3-7.6) pmol/mg muscle, P=0.7 in lean and obese, respectively] concentrations in skeletal muscle.
  
  
  CONCLUSIONS
  Short-term manipulation of plasma FFAs has no effect on ceramide and glucosylceramide concentrations in skeletal muscle from lean and obese subjects.
authors.affiliation: Department of Endocrinology and Metabolism, Laboratory of Endocrinology, Academic Medical Center F5-169, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. m.j.serlie@amc.uva.nl
authors.forename: M J
authors.initials: MJ
authors.lastname: Serlie
authors.forename: A J
authors.initials: AJ
authors.lastname: Meijer
authors.forename: J E
authors.initials: JE
authors.lastname: Groener
authors.forename: M
authors.initials: M
authors.lastname: Duran
authors.forename: E
authors.initials: E
authors.lastname: Endert
authors.forename: E
authors.initials: E
authors.lastname: Fliers
authors.forename: J M
authors.initials: JM
authors.lastname: Aerts
authors.forename: H P
authors.initials: HP
authors.lastname: Sauerwein
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D002518:Ceramides / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005963:Glucosylceramides / Q000378:metabolism*; D006019:Glycolysis; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity / Q000097:blood / Q000378:metabolism; D050177:Overweight / Q000502:physiology*; D019308:Palmitic Acid / Q000378:metabolism; D013851:Thinness
chemical_list: D002518:Ceramides; D005230:Fatty Acids, Nonesterified; D005963:Glucosylceramides; D019308:Palmitic Acid