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 [14C]-cholesterol ester and [³H]-triglycerides and injected intravenously into ten normolipidemic non-diabetic patients with grade III obesity [body mass index higher than 40 kg/m²] 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.

Efeitos do treinamento físico sobre a remoção plasmática de nanopartículas lipídicas que se ligam a receptores de LDL e sobre a oxidação da lipoproteína, em indíviduos hipercolesteolêmicos / Effects of exercise training on plasma removal of lipidic nanoparticle which binds to LDL receptors and on lipoprotein oxidation, in hypercholesterolemic individuals

Foram avaliados os efeitos do exercício físico no metabolismo de uma nanoemulsão lipídica artificial (LDE) semelhante à LDL natural, na hipercolesterolemia. Foram avaliados indivíduos sedentários hipercolesterolêmicos e normolipidêmicos submetidos a treinamento físico durante 4 meses e indivíduos controles sedentários, hipercolesterolêmico e normolipidêmico, que não realizaram exercício físico. A LDE foi marcada com colesterol éster-14C (CE-14C), injetada endovenosamente e a taxa fracional de remoção (TFR) calculada por análise compartimental. No grupo hipercolesterolêmico treinado a TFR do CE-14C foi maior após o treinamento. Não ocorreram mudanças na TFR nos outros grupos estudados. Portanto, o exercício físico acelera a remoção plasmática da LDL em indivíduos hipercolesterolêmicos. Este efeito pode ser um dos mecanismos pelo qual o exercício previne a doença arterial coronariana.

The effects of exercise on the metabolism of an artificial lipid nanoemulsion (LDE) similar to natural LDL were evaluated in hypercholesterolemia. Both hypercholesterolemic and normolipidemic sedentary individuals submitted to a 4-month training program and hypercholesterolemic and normolipidemic sedentary individuals with no training were evaluated. LDE labeled with 14C-cholesteryl oleate (14C-CO) was injected endovenously and the fractional clearance rate (FCR) calculated by compartmental analysis. The trained hypercholesterolemic group presented a higher 14C-CO-FCR after exercise. There was no change in the FCR of the other groups. Thus, exercise accelerates the removal of LDL in hypercholesterolemic individuals. This effect can be one of the mechanisms by which exercise prevents arterial heart disease.