Clinical significance of plasma apolipoprotein F in Japanese healthy and hypertriglyceridemic subjects

Aim: apolipoprotein f (apo f),also known as lipid transfer inhibitory protein (ltip),is a protein component of plasma lipoprotein classes including hdl and functions to inhibit lipid transfer between lipoproteins in vitro. to study the role of plasma apo f,a reliable and sensitive tool for the quantification would be needed. methods: we have developed a sandwich elisa using two monoclonal antibodies for human plasma apo f,and analyzed apo f concentration in 397 japanese healthy and 221 hypertriglyceridemic subjects. results: our elisa enables apo f to be assayed in the range of 0.6-25 μg/ml with intra- and interassay coefficients of variation less than 3.8% and 7.8%,respectively. in healthy subjects,plasma apo f concentration was 12.5±2.9 μg/ml (mean±sd),and was significantly higher in females than in males (p<0.05). by linear regression analysis in healthy subjects,plasma apo f concentration correlated positively with hdl cholesterol and apo a-i levels,and in males but not in females,negatively with apo b and triglyceride levels. it also correlated negatively with intrinsic cetp activity measured using intrinsic apo b-containing lipoprotein as an acceptor,and positively with pltp mass and apo j levels. apo f concentration in hypertriglyceridemic patients (10.3±3.1 μg/ml) was lower than in healthy controls (p<0.0001) and correlated positively with pltp mass. conclusions: our elisa is reliable and sensitive for the quantification of plasma apo f concentration. this system can be applicable for clinical significance in lipoprotein metabolism and reverse cholesterol transport.