Abstract: Objective In the present study, we examined the effects of high-density lipoprotein (HDL) and lipoprotein-deficient serum (LPDS) isolated from patients with type 2 diabetes mellitus on cholesterol efflux through human skin fibroblast (HSF) and human hepatoma cell line (HepG2). Methods and Results Blood was collected from 13 patients with type 2 diabetes mellitus and 17 healthy volunteers and HDL and LPDS were isolated. Cholesterol efflux assays, RT-PCR and western blot were performed on HSF and HepG2 cells. The HepG2 cells have a high expression of scavenger receptor B1(SR-B1) and lack functional ATP-binding cassette receptor A1(ABCA1) and ATP-binding cassette receptor G1(ABCG1) while HSF cells express SR-B1 at very low levels and have a high expression of ABCA1 pretreated with 22-OH cholesterol. The cholesterol efflux from HepG2 cells to HDL isolated from patients with diabetes decreased significantly compared to controls. However, cholesterol efflux from HSF cells to LPDS was not different between groups. Conclusion The function of HDL involving cholesterol efflux in type 2 diabetes mellitus was impaired while cholesterol efflux induced by LPDS from HSF cells was maintained, implying that HDL plays a critical role in mediation of intracellular cholesterol accumulation and progression of atherosclerosis in patients with type 2 diabetes.

Key words: High-density lipoprotein, Lipoprotein-deficient serum, diabetes mellitus, cholesterol efflux