title: Impact of postprandial variation in triglyceridemia on low-density lipoprotein particle size.
abstract: The fasting atherogenic dyslipidemia of visceral obesity, which includes the presence of small, dense low-density lipoprotein (LDL) particles, is predictive of an increased risk of coronary heart disease (CHD). It has also been suggested that progression of atherosclerosis may be accelerated in the presence of postprandial hyperlipidemia independently from the fasting dyslipidemic state. Studies have shown that the best predictor of postprandial hyperlipidemia and of the small, dense LDL phenotype is fasting triglyceride (TG) concentration. In the present study, we evaluated the impact of postprandial hypertriglyceridemia on the variation in LDL particle size. Fasting (0 hour) and postprandial changes (2, 4, 6, and 8 hours) in LDL particle size were measured by nondenaturing 2% to 16% polyacrylamide gel electrophoresis in a sample of 49 men (mean age +/- SD: 46.6 +/- 9.2 years) who underwent a standardized breakfast with a high-fat (64% calories as fat) content. The postprandial increase in TG levels was associated with a transient reduction in LDL particle size, the most substantial reduction being observed 4 hours (-1.0 +/- 2.4 A) after the oral fat load. Although there were strong correlations between TG-rich lipoprotein (TRL)-TG levels and LDL particle size in the fasting state (r=-0.71, P<.0001) as well as 4 hours after the oral fat load (r=-0.70, P<.0001), changes in TRL-TG concentrations during the postprandial state (from time 0 to 4 hours) were not associated with changes in LDL particle size during this period (r=-0.04, not significant [NS]). However, among subgroups of men matched for similar fasting TRL-TG levels (n=12), subjects with the highest total area under the curve (AUC) of TRL-TG after the fat load were characterized by smaller LDL particle size at 6 and 8 hours compared with men with the lowest AUC TRL-TG (P<.02). Men displaying the highest postprandial AUC TRL-TG were also characterized by the greatest accumulation of visceral adipose tissue (AT) (P<.05). These results indicate that the hypertriglyceridemic (hyperTG) state induced by a high-fat meal is associated with a transient reduction in LDL peak particle diameter, which is not proportionate, however, to the level of TG achieved in the postprandial state. Furthermore, despite similar TG levels at baseline, viscerally obese men with an impaired postprandial lipemia had smaller LDL particles at the end of the oral fat load than obese men with a lower accumulation of visceral AT.
authors: Québec Heart Institute, Laval Hospital Research Center, Ste-Foy, Québec, Canada.
authors: Patricia
authors: P
authors: Blackburn
authors: Mélanie
authors: M
authors: Côté
authors: Benoît
authors: B
authors: Lamarche
authors: Charles
authors: C
authors: Couillard
authors: Agnès
authors: A
authors: Pascot
authors: Angelo
authors: A
authors: Tremblay
authors: Jean
authors: J
authors: Bergeron
authors: Isabelle
authors: I
authors: Lemieux
authors: Jean-Pierre
authors: JP
authors: Després
mesh_terms: D000328:Adult; D000886:Anthropometry; D000925:Anticoagulants; D001823:Body Composition / Q000502:physiology; D006493:Heparin; D006801:Humans; D008049:Lipase / Q000097:blood; D008055:Lipids / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D019518:Postprandial Period / Q000502:physiology*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
chemical_list: D000925:Anticoagulants; D008055:Lipids; D008077:Lipoproteins, LDL; D014280:Triglycerides; D006493:Heparin; D008049:Lipase