Plasma apolipoprotein CII levels in hypertriglyceridemia.

It is known that hypertriglyceridemia is associated with the elevation of plasma apolipoprotein CII (apoCII). In an attempt to look at the relationship between the two, the present study was conducted. We examined 30 patients with hypertriglyceridemia (TG, 210 to 9,127 mg/dL) and ten normolipidemic controls. Hypertriglyceridemic patients included 7 of type I hyperlipoproteinemia (HL), 17 of type IV, and 6 of type V. Plasma apoCII was measured by the single radial immunodiffusion method. Major cause for any difference in plasma apoCII could be attributed to differences in the TG-rich lipoproteins. Since a model for the lipoprotein structure indicates that TG-rich lipoproteins are spherical, with apoCII as a surface component and TG as a core substance, we calculated the square roots and the cubic roots of the values of apoCII and TG to make comparison possible. When the two variables were plotted on the X and Y axes respectively, we obtained the regression line of square root of apoCII = 0.37 X 3 the square root of TG - 0.03 with a correlation coefficient of r = .95 (P less than 0.001). The result indicates that a lipoprotein structural model accounts well for the relationship between apoCII and TG. Although a previous report suggested a compensatory increase of apoCII in lipoprotein lipase deficiency, our patients with type I HL had apoCII levels similar to those who had comparable levels of plasma TG.