Chylomicron and very-low-density lipoprotein levels in type I hyperlipoproteinaemia. The role of the liver in determining biochemical phenotype
Berger, G.M.; Van der Westhuyzen, J.H.; Huskisson, J.; Bonnici, F.; Henderson, H.E.
South African Medical Journal 61(8): 266-272
1982
ISSN/ISBN: 0256-9574 PMID: 7058458 Document Number: 194790
Patients with type I hyperlipoproteinemia present with relatively normal plasma levels of very-low-density lipoprotein (VLDL) together with marked hyperchylomicronemia. Since the etiological basis for the type I phenotype is a severe reduction in peripheral lipoprotein (LPL) activity, the discrepancy between the 2 triglyceride-rich lipoprotein fractions is paradoxical. In order to account for these observations, it was previously proposed that the hepatic secretion of lipoproteins in these patients is characterized by the production of chylomicron-like particles rather than VLDL. The implications of this hypothesis were examined in 3 patients with type I hyperlipoproteinemia. A high-carbohydrate diet led to the enhancement of hyperchylomicronemia in 2 of the 2 subjects. The severity of the defect in peripheral LPL activity correlated with the tendency to hyperchylomicronemia, and in vitro assay suggested that hepatic lipase was capable of hydrolyzing chylomicron triglyceride when present at the high concentrations characteristic of type 1 hyperlipoproteinemia. This was compatible with the above hypothesis implicating the liver as a partial determinant of the type I phenotype.