title: Moderate Exercise Increases Affinity of Large Very Low-Density Lipoproteins for Hydrolysis by Lipoprotein Lipase.
abstract: BACKGROUND
  Postprandial triglyceride (TG) concentration is independently associated with cardiovascular disease risk. Exercise reduces postprandial TG concentrations, but the mechanisms responsible are unclear.
  
  
  OBJECTIVE
  The objective was to determine the effects of exercise on affinity of chylomicrons, large very low-density lipoproteins (VLDL1), and smaller VLDL (VLDL2) for lipoprotein lipase (LPL)-mediated TG hydrolysis.
  
  
  METHODS
  This was designed as a within-participant crossover study.
  
  
  METHODS
  The setting was a university metabolic investigation unit.
  
  
  METHODS
  Participants were 10 overweight/obese men.
  
  
  METHODS
  Participants undertook two oral fat tolerance tests, separated by 7-14 days, in which they had blood taken while fasting and for 4 hours after a high-fat mixed meal. On the afternoon before one test, they performed a 90-minute treadmill walk at 50% maximal oxygen uptake (exercise trial [EX]); no exercise was performed before the control trial (CON).
  
  
  METHODS
  We measured circulating TG-rich lipoprotein concentrations and affinity of chylomicrons, VLDL1, and VLDL2 for LPL-mediated TG hydrolysis.
  
  
  RESULTS
  Exercise significantly reduced fasting VLDL1-TG concentration (CON, 0.49 [0.33-0.72] mmol.L(-1); EX, 0.36 [0.22-0.59] mmol.L(-1); geometric means [95% confidence interval]; P = .04). Time-averaged postprandial chylomicron-TG (CON, 0.55 ± 0.10 mmol.L(-1); EX, 0.39 ± 0.08 mmol.L(-1); mean ± SEM; P = .03) and VLDL1-TG (CON, 0.85 ± 0.13 mmol.L(-1); EX, 0.66 ± 0.10 mmol.L(-1); P = .01) concentrations were both lower in EX than CON. Affinity of VLDL1 for LPL-mediated TG hydrolysis increased by 2.2 (1.3-3.7)-fold [geometric mean (95% confidence interval)] (P = .02) in the fasted state and 2.6 (1.8-2.6)-fold (P = .001) postprandially. Affinity of chylomicrons and VLDL2 was not significantly different between trials.
  
  
  CONCLUSIONS
  Exercise increases affinity of VLDL1 for LPL-mediated TG hydrolysis both fasting and postprandially. This mechanism is likely to contribute to the TG-lowering effect of exercise.
authors: Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
authors: Khloud
authors: K
authors: Ghafouri
authors: Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
authors: Josephine
authors: J
authors: Cooney
authors: Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
authors: Dorothy K
authors: DK
authors: Bedford
authors: Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
authors: John
authors: J
authors: Wilson
authors: Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
authors: Muriel J
authors: MJ
authors: Caslake
authors: Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom.
authors: Jason M R
authors: JM
authors: Gill
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D006868:Hydrolysis; D050356:Lipid Metabolism / Q000502:physiology; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008079:Lipoproteins, VLDL / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism; D050177:Overweight / Q000378:metabolism; D013379:Substrate Specificity; D055815:Young Adult
chemical_list: D008079:Lipoproteins, VLDL; D008071:Lipoprotein Lipase