Apolipoprotein A-II and adiponectin as determinants of very low-density lipoprotein apolipoprotein B-100 metabolism in nonobese men

Data from cellular systems and transgenic animal models suggest a role of apolipoprotein (apo) A-II in the regulation of very low-density lipoprotein (VLDL) metabolism. However, the precise mechanism whereby apoA-II regulates VLDL metabolism remains to be elucidated in humans. In this study, we examined the associations between the kinetics of high-density lipoprotein (HDL)-apoA-II and VLDL-apoB-100 kinetics, and plasma adiponectin concentrations. The kinetics of HDL-apoA-II and VLDL-apoB-100 were measured in 37 nonobese men using stable isotope techniques. Plasma adiponectin concentration was measured using immunoassays. Total plasma apoA-II concentration was positively associated with HDL-apoA-II production rate (PR) (r = 0.734, P < .01); both were positively associated with plasma triglyceride concentration (r = 0.360 and 0.369, respectively) and VLDL-apoB-100 PR (r = 0.406 and 0.427, respectively), and inversely associated with plasma adiponectin concentration (r = −0.449 and −0.375, respectively). Plasma adiponectin was inversely associated with plasma triglyceride concentration (r = −0.327), VLDL-apoB-100 concentration (r = −0.337), and VLDL-apoB-100 PR (r = −0.373). In multiple regression models including waist circumference and plasma insulin, plasma adiponectin concentration was an independent determinant of total plasma apoA-II concentration (β-coefficient = −0.508, P = .001) and HDL-apoA-II PR (β-coefficient = −0.374, P = .03). Conversely, total plasma apoA-II concentration (β-coefficient = 0.348, P = .047) and HDL-apoA-II PR (β-coefficient = −0.350, P = .035) were both independent determinants of VLDL-apoB-100 PR. However, these associations were not independent of plasma adiponectin. Variation in HDL apoA-II production, and hence total plasma apoA-II concentration, may exert a major effect on VLDL-apoB-100 production. Plasma adiponectin may also contribute to the variation in VLDL-apoB-100 production partly by regulating apoA-II transport.