Lipoprotein remnants and endothelial dysfunction in the postprandial phase

The objective of this work was to study whether changes in remnant lipoprotein (RLP) plasma levels during the postprandial phase relate to alterations of the endothelial function. Fasted patients (15 moderately dyslipidemic men) were given an oral fat load (OFL), and blood samples were collected before the OFL ingestion (T0) and 2, 4, 6, and 8 h (T2, T4, T6, T8) thereafter. Endothelial function, determined as flow-mediated dilatation (FMD) of the brachial artery, was assessed at the same time points. Triglyceridemia peaked between T4 (5.48 ± 0.64 mmol/liter) and T6 (5.34 ± 0.89 mmol/liter) and decreased at 8 h (4.36 ± 0.87 mmol/liter) after the OFL. FMD decreased significantly 6 h after the OFL consumption (from 16.03 ± 1.32% to 11.53 ± 1.42%, P <0.01). Cholesterol in RLPs increased steadily up to 6 h and decreased at 8 h (T0 0.53 ± 0.10, T6 0.81 ± 0.11, T8 0.73 ± 0.13 mmol/liter). Fasting levels of triglycerides and cholesterol-RLPs (C-RLPs) correlated significantly with FMD at baseline. The decrease in endothelial function at 6 h also significantly correlated with the area under the curve of triglycerides (R = 0.53, P = 0.04). Postprandial C-RLPs (area under the curve), however, showed the best correlation with the decrease of FMD (R = 0.63, P = 0.012). The correlation persisted in a multivariate analysis. We concluded that C-RLPs contribute significantly to the endothelial dysfunction occurring during the postprandial lipemia.