Implications of decreased serum adiponectin for type IIb hyperlipidaemia and increased cholesterol levels of very-low-density lipoprotein in type II diabetic patients

Abstract

The present study was performed to investigate the relevance of cholesterol levels of plasma lipoproteins [HDL (high-density lipoprotein), LDL (low-density lipoprotein), IDL (immediate-density lipoprotein), VLDL (very-LDL) and chylomicrons] determined by a novel HPLC method, with adiponectin, which is decreased in Type II diabetes and assumed to be involved in dysregulated metabolism and atherogenesis. Type II diabetic patients who were not treated with insulin, statins and fibrates were enrolled. Study subjects included Type II diabetic patients with normolipidaemia (DM-NL; n=15), type 4 hyperlipidaemia (DM-T4HL; n=13), Type IIa hyperlipidaemia (DM-T2aHL; n=15) and Type IIb hyperlipidaemia (DM-T2bHL; n=13). Fasting blood samples were collected. The serum adiponectin level was lower in DM-T2bHL than in any of the other groups. Cholesterol levels of each lipoprotein fraction, serum triacylglycerol (triglyceride), remnant-like particle-cholesterol, fasting plasma glucose, HbA1c (glycated haemoglobin), age, gender difference and BMI (body mass index) were incorporated into a stepwise regression analysis as independent variables. VLDL-cholesterol correlated inversely with adiponectin independently of age, BMI, gender difference and glycaemic control. Although the mechanisms remain to be explored, serum adiponectin was reduced particularly in Type II diabetics with type IIb hyperlipidaemia and correlated inversely with VLDL-cholesterol. Measuring VLDL-cholesterol may be helpful for understanding the pathological features of diabetic dyslipidaemia.