Serum lipoprotein fatty acid patterns in various types of familiar combined hyperlipidemia

The relative content of various fatty acids in serum lipoproteins was determined in patients with type IIa (38), IIb (49) and IV (77) of hyperlipoproteinemia and compared with 52 controls. Significant changes were found in hyperlipoproteinemia associated with hypertriglyceridemia (type IV) but not in "pure" hypercholesterolemia (type IIa). In all lipoprotein fractions (VLDL, LDL, HDL) in type IV of hyperlipoproteinemia the increased oleic and linolenic acid proportions were found, while proportions of linoleic, arachidonic and docosahexaenoic acids were decreased. The saturated fatty acids (myristic, palmitic and stearic) were found increased in LDL. Linear regression analysis has shown positive correlation between the content of arachidonic and docosahexaenoic acids in HDL and LDL and the serum levels of total HDL-cholesterol, HDL2-cholesterol, HDL3-cholesterol and ApoA1, while a negative correlation between these fatty acids and serum triglycerides level appeared. These findings can be explained partly by increased content of triglycerides and free fatty acids in lipoproteins. Possible differences concerning mechanisms of accelaration of atherogenesis in various types of hyperlipidemia are discussed.