A possible mechanism linking hyperglycemia and reduced high-density lipoprotein cholesterol levels in diabetes.

This study investigated the role of glucose in the biogenesis of high-density lipoprotein cholesterol (HDL-C). Mouse primary peritoneal macrophages were harvested and maintained in Dulbecco's modified Eagle's medium (DMEM) containing glucose of various concentrations. The cells were divided into 3 groups in terms of different glucose concentrations in the cultures: Control group (5.6 mmol/L glucose), high glucose concentration groups (16.7 mmol/L and 30 mmol/L glucose). ATP-binding cassette transporter A1 (ABCA1) mRNA expression in the macrophages was detected by semi-quantitative RT-PCR 24, 48 and 72 h after glucose treatment. The results showed that ABCA1 mRNA expression in the 16.7 mmol/L glucose group was not significantly different from that in the control group at all testing time points (P>0.05 for each). In the 30 mmol/L glucose group, macrophage ABCA1 mRNA expression was not changed significantly at 24 h (P=0.14), but was substantially decreased by 40.4% at 48 h (P=0.009) and by 48.1% at 72 h (P=0.015) as compared with that in the control group. It was concluded that ABCA1 is of vital importance for HDL-C biogenesis. High glucose may hamper HDL-C biogenesis by decreasing ABCA1 expression, which contributes to low HDL-C level in diabetes.