Plasma apolipoprotein AV levels in mice are positively associated with plasma triglyceride levels

Apolipoprotein AV (apoAV) overexpression causes a decrease in plasma triglyceride (TG) levels, while deficiency of apoAV causes hypertriglyceridemia in both men and mice. However, contrary to what would be expected, plasma apoAV and TG levels in humans are positively correlated. To address this apparent paradox, we determined plasma apoAV levels in various mouse models with median TG levels ranging from 30 mg/dl in wild-type mice to 2089 mg/dl in glycosylphosphatidylinositol-anchored HDL binding protein 1-deficient mice. The data show that apoAV and TG levels are positively correlated in mice (r = +0.798, P < 0.001). In addition, we show that LPL gene transfer caused a simultaneous decrease in TG and apoAV in LPL-deficient mice. The combined data suggest that apoAV levels follow TG levels due to an intimate link between the apoAV molecule and TG-rich lipoproteins, comprising both secretion and removal of these lipoproteins. Taken together, the data suggest that higher plasma apoAV levels reflect an increased demand for plasma TG hydrolysis under normal physiological conditions.