Apolipoprotein A-II affects HDL apolipoprotein composition and HDL-mediated lipoprotein lipase activation

Introduction: Apolipoprotein (apo)A-II is the second most abundant HDL protein but its function remains largely unknown. Studies in humans and genetically-modified mice have demonstrated a role for apoA-II in triglyceride metabolism. The main objective of this study was to evaluate the relationship between apoA-II and HDL apolipoprotein composition, as well as HDL-mediated lipoprotein lipase (LPL) coactivation and plasma triglyceride concentration. Methods: Eleven-hour fasting blood samples were taken from 32 healthy volunteers. Anthropometric data and lipid and apolipoprotein parameters were analyzed. HDL isolated by ultracentrifugation was incubated in the presence of a triolein-based emulsion and bovine LPL. In 14 of these volunteers, an additional blood sample was taken 3. h after breakfast. Results: ApoA-II concentration was directly correlated with plasma triglycerides (R=0.55, p<0.05) and inversely correlated with the HDL-apoC-II+apoE/apoC-III ratio (R=-0.43, p<0.05). ApoA-II was also inversely correlated with HDL-mediated LPL coactivation (R=-0.35, p<0.05). ApoA-II concentration was directly correlated with plasma triglycerides 3. h after the fat-loading test (R=0.58, p<0.05). Conclusion: These results show that HDL-apoA-II levels play a crucial role in triglyceride catabolism and suggest that, at least in part, this is due to modulation of LPL activity. © 2010 Elsevier España, S.L. y SEA.