Metabolism of a Lipid Nanoemulsion Resembling Low-Density Lipoprotein in Patients with Grade III Obesity

INTRODUCTION Obesity increases triglyceride levels and decreases high-density lipoprotein concentrations in plasma. Artificial emulsions resembling lipidic plasma lipoprotein structures have been used to evaluate low-density lipoprotein metabolism. In grade III obesity, low density lipoprotein metabolism is poorly understood. OBJECTIVE To evaluate the kinetics with which a cholesterol-rich emulsion (called a low-density emulsion) binds to low-density lipoprotein receptors in a group of patients with grade III obesity by the fractional clearance rate. METHODS A low-density emulsion was labeled with [(14)C]-cholesterol ester and [(3)H]-triglycerides and injected intravenously into ten normolipidemic non-diabetic patients with grade III obesity [body mass index higher than 40 kg/m(2)] and into ten non-obese healthy controls. Blood samples were collected over 24 hours to determine the plasma decay curve and to calculate the fractional clearance rate. RESULTS There was no difference regarding plasma levels of total cholesterol or low-density lipoprotein cholesterol between the two groups. The fractional clearance rate of triglycerides was 0.086 +/- 0.044 in the obese group and 0.122 +/- 0.026 in the controls (p = 0.040), and the fractional clearance rate of cholesterol ester (h(-1)) was 0.052 +/- 0.021 in the obese subjects and 0.058 +/- 0.015 (p = 0.971) in the controls. CONCLUSION Grade III obese subjects exhibited normal low-density lipoprotein removal from plasma as tested by the nanoemulsion method, but triglyceride removal was slower.