Bimodal distribution of cholesteryl ester transfer protein activities in normotriglyceridemic men with low HDL cholesterol concentrations

Abstract

Increased plasma activities of cholesteryl ester transfer protein (CETP) theoretically could lower HDL cholesterol levels due to enhanced transfer of cholesteryl esters from HDL to apo B-containing lipoproteins. To determine whether high CETP activities are associated with isolated hypoalphalipoproteinemia, CETP activities were measured in 109 adult men with HDL cholesterol <35 mg/dL, plasma triglycerides <200 mg/dL, and LDL cholesterol <160 mg/dL; the results were compared with those of 50 normolipidemic (HDL cholesterol >40 mg/dL) male subjects. CETP activities were assayed in vitro and expressed as the percent of [3H]cholesteryl ester transferred from HDL3 to LDL during a 16-hour incubation. In addition, postheparin plasma activities of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) were determined in 71 patients with a low HDL cholesterol level. Distributions of CETP activities were unimodal in control subjects (mean±SD, 23.1±5.0%), but they were bimodal in the low-HDL patients. Among the latter, 27 patients had elevated CETP activities (40.8±4.6%), whereas 82 patients had CETP activities that overlapped the normal range (26.14±7.6%). Low-HDL patients with normal CETP activities had 20% lower LPL activities (P = .01), 25% higher HTGL activities (P=.03), and 63% lower LPL/HTGL ratios (P