Triglyceride-rich lipoprotein metabolism in women: roles of apoC-II and apoC-III

Abstract

Background <p>Experimental data suggest that apolipoprotein (apo) C-II and C-III regulate triglyceride-rich lipoprotein (TRL) metabolism, but there are limited studies in humans. We investigated the metabolic associations of TRLs with apoC-II and apoC-III concentrations and kinetics in women.</p> Material and methods <p>The kinetics of plasma apoC-II, apoC-III and very low-density lipoprotein (VLDL) apoB-100 and triglycerides were measured in the postabsorptive state using stable isotopic techniques and compartmental modelling in 60 women with wide-ranging body mass index (19·5-32·9 kg/m²).</p> Results <p>Plasma apoC-II and apoC-III concentrations were positively associated with the concentrations of plasma triglycerides, VLDL₁- and VLDL₂-apoB-100 and triglyceride (all <i>P</i> < 0·05). ApoC-II production rate (PR) was positively associated with VLDL₁-apoB-100 concentration, VLDL₁ triglyceride concentration and VLDL₁ triglyceride PR, while apoC-II fractional catabolic rate (FCR) was positively associated with VLDL₁ triglyceride FCR (all <i>P</i> < 0·05). No significant associations were observed between apoC-II and VLDL₂ apoB-100 or triglyceride kinetics. ApoC-III PR, but not FCR, was positively associated with VLDL₁ triglyceride, and VLDL₂-apoB-100 and triglyceride concentrations (all <i>P</i> < 0·05). No significant associations were observed between apoC-III and VLDL-apoB-100 and triglyceride kinetics. In multivariable analysis, including homoeostasis model assessment score, menopausal status and obesity, apoC-II concentration was significantly associated with plasma triglyceride, VLDL₁-apoB-100 and VLDL₁ triglyceride concentrations and PR. Using the same multivariable analysis, apoC-III was significantly associated with plasma triglyceride and VLDL₁- and VLDL₂-apoB-100 and triglyceride concentrations and FCR.</p> Conclusions <p>In women, plasma apoC-II and apoC-III concentrations are regulated by their respective PR and are significant, independent determinants of the kinetics and plasma concentrations of TRLs.</p>