Endothelial lipase and reverse cholesterol transport in type 2 diabetes mellitus

Abstract

Aims/Introduction: Endothelial lipase (EL) plays an important role in high-density lipoprotein (HDL) metabolism and experimental data suggest that EL might be proatherogenic. We have investigated whether serum EL concentration is associated with changes in serum capacity to induce cholesterol efflux and arterial stiffness in type 2 diabetes. Materials and Methods: Serum EL was assayed by ELISA in 172 diabetic patients and 175 controls. The ability of serum to induce cholesterol efflux was measured using a cell culture system and arterial stiffness was determined by measuring pulse wave velocity (PWV) between carotid and femoral arteries. Results: Diabetic patients had significantly higher C-reactive protein (CRP) and EL (27.7 ± 16.6 ng/mL vs 24.0 ± 11.3, P < 0.05). Cholesterol efflux to serum mediated through scavenger receptor class B type I was impaired (15.1 ± 2.5% vs 16.7 ± 3.1, respectively, P < 0.01). In controls, serum EL correlated with cholesterol efflux to serum (r =)0.16, P = 0.025), but only a trend was seen in the diabetic patients. Linear regression showed that in controls, HDL, serum EL and waist circumference were major independent determinants of cholesterol efflux; whereas in the diabetic cohort, the major independent determinants of cholesterol efflux were HDL, CRP and age. PWV was increased in the diabetic patients (P < 0.01), but no association between serum EL and PWV was seen in either groups. Conclusions: Serum EL was increased in diabetic patients, but impaired serum capacity to induce cholesterol efflux in these patients was mainly related to low HDL and subclinical inflammation. © 2010 Asian Association for the Study of Diabetes and Blackwell Publishing Asia Pty Ltd.