Abstract
Background 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. Material and methods 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 modeling in 60 women with wide-ranging body mass index (19.5-32.9kg/m2). Results Plasma apoC-II and apoC-III concentrations were positively associated with the concentration of plasma triglycerides, VLDL1- and VLDL2- apoB-100 and triglyceride (all P<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 P<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 P<0.05). No significant associations were observed between apoC-III and VLDL- apoB-100 and triglyceride kinetic. In multivariable analysis, including homeostasis model assessment score, menopausal status and obesity, apoC-II concentration was significantly associated with plasma triglyceride, VLDL1 apoB-100 and -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. Conclusions In women, plasma apoC-II and apoC-III concentrations are regulated by their respective production rates and are significant, independent determinants of the kinetics and plasma concentrations of TRLs.