Lipid and apoprotein behaviour after oral fat load in hypertriglyceridaemia.

Post-prandial profiles of plasma lipids and apoproteins have been studied in 13 hypertriglyceridaemic patients and in 24 normolipidaemic subjects who acted as controls. Triglyceride curves were different in the two groups: type IV patients reached the peak later than the controls (7-h vs 4 1/2-h) and cleared plasma triglycerides more slowly. The magnitude of post-prandial response was found to be higher in hypertriglyceridaemic patients. Positive correlations were also found between triglycerides response and fasting levels of triglycerides, apo B, apo C-II, apo C-III and apo E levels and negative correlations (not significant) with HDL-C levels in both hypertriglyceridemics and controls. In normolipidaemic subjects the triglyceride increase area was also correlated with age, BMI and total cholesterol, while in type IV patients with apo A-I and apo A-II levels. These data confirm that the magnitude of post-prandial phase is influenced by fasting levels of triglycerides-rich lipoproteins and that HDL are important determinants in the control of the post-prandial response. The most relevant finding in this study was the difference of the post-prandial profile of apoproteins C-II, C-III and E. These apoproteins significantly decreased nine hours after meal in the controls, while in hypertriglyceridaemics these apoproteins showed a rise over time. On the contrary apo A-I, apo A-II and apo B curves presented a similar profile in both groups. Possible mechanisms have been discussed, but further studies are necessary to understand the metabolic defects responsible for this behaviour in hypertriglyceridaemia.