CETP IN RARE DYSLIPIDEMIAS

Objective: To determines CETP mass and activity in rare disorders of HDL metabolism. Methods: Patients: Fasting plasma samples were obtained from two individuals with TD and from patients with LCAT deficiency, analphalipoproteinemia, Hepatic lipase deficiency (HL), vasculitis, and hypoalphalipoprteinemia. Their clinical and laboratory findings have been previously reported. Assay: CETP activity was measured using commercial CETP Fluorescence kit (Roar Biomedical Inc., New York, NY). The kit includes donor (without apoA-I) and acceptor lipoprotein particles. Incubation of donor and acceptor with a CETP source results in the CETP mediated transfer of fluorescent neutral lipid from donor to acceptor, rate of which is determined by the increase in fluorescence intensity as the fluorescent neutral lipid is removed from the donor to the acceptor. The amount of fluorescent substrate transferred was expressed as pmoles of fluorescent substrate transferred within 3 hours. CETP concentration was measured by ELISA using specific rabbit antibody against human CETP. Results: While CETP mass correlated with serum HDL-C levels, the activity decreased in patients with LCAT deficiency, FED, HL deficiency and vascultis, but increased in TD. We speculate that the composition of HDL particles in these disorders differs and results in the different CE transfer rates. Conclusion: CETP mass correlates with the HDL-C concentration but the activity differ widely among the patients with rare disorders of HDL metabolism, probably due to the changes in HDL quality