EFFECTS OF APOLIPOPROTEIN-E POLYMORPHISM ON PLASMA LIPOPROTEIN(A) LEVELS

Effects of apolipoprotein E (apo E) genetic polymorphism on plasma lip oprotein(a) (Lp(a)) levels were investigated in 305 civil service work ers (168 men and 147 women). Plasma Lp(a) levels were measured by ELIS A. Apo E phenotypes were determined from plasma by isoelectric focusin g, Western blotting and immunostaining, as we previously reported. A t otal of 305 subjects were divided into the three apo E groups; apo E2 group (n=19 for apo E3/2 and n=4 for apo E4/2), Apo E3/3 group (n=224) and apo E4/3 group (n=58). Mean levels of plasma Lp(a) were 14.2 mg/d l. Plasma Lp(a) levels were significantly lower in the apo E2 group (6 .6 mg/dl) than in the apo E3/3 (15.1 mg/dl) and E4/3 (13.7 mg/dl) grou ps. Plasma total cholesterol (T-chol) and low density lipoprotein (LDL )-chol levels were significantly lower in the apo E2 group than in the apo E4/3 group and tended to be highest in the apo E4/3 group. A sign ificant positive correlation was noted between plasma Lp(a) levels and plasma LDL-chol levels, indicating that the effects of apo E polymorp hism on plasma Lp(a) levels were parallel to its effects on plasma LDL -chol levels. In women plasma Lp(a) levels were significantly lower in the apo E2 group than in the apo E3/3 and E4/3 groups, whereas in men plasma Lp(a) levels tended to be. lower in the apo E2 group but no si gnificant difference was noted among the three apo E groups. It is con cluded that plasma Lp(a) levels are, at least in part, modulated by ap o E polymorphism (particularly apo E2) and that there is a gender diff erence in the effects of apo E polymorphism on plasma Lp(a) levels.