Detailed analysis of serum lipids and lipoproteins from Japanese type III hyperlipoproteinemia with apolipoprotein E2/2 phenotype

Abstract

Background: To clarify a detailed profile of serum lipids, lipoproteins and apolipoproteins (apo) in type III hyperlipoproteinemia (HLP) with apolipoprotein E (apo E) phenotype 2/2. Methods: Nineteen consecutive Japanese type III HLP (9 men, 10 women) were studied. All had hypertriglyceridemia and 74% showed hypercholesterolemia. Results: The degree of hyperlipidemia [total cholesterol (TC) 8.1±3.2 mmol/l, triglycerides (TG) 5.2±2.9 mmol/l] was milder than that in type III HLP in western countries. Lipoprotein fractions analyzed by ultracentrifugation showed that very low density lipoprotein cholesterol (VLDL-C) concentrations were considerably increased and that intermediate density lipoprotein cholesterol (IDL-C) concentrations were also increased, whereas low-density lipoprotein cholesterol (LDL-C) concentrations were low. Serum apo A-I, A-II and B concentrations were not increased, while apo C-II, C-III and E concentrations were considerably increased. However, the increase of apo E concentrations in the study subjects was far more pronounced than that of apo C-III, causing the ratio of apo E/C-III to be considerably higher than hyperlipidemia with other apo E phenotypes. Conclusion: By using this index apo E/C-III, it is possible to segregate type III HLP with apo E2/2 phenotype from other types of hyperlipidemia.