Serum small and dense low-density lipoprotein-cholesterol and lipoproteins levels in type 2 diabetic patients and the influence of insulin therapy on lipid metabolism

Abstract

Objective To investigate the levels of small and dense low-density lipoprotein-cholesterol (sdLDL-C) and the influence of insulin therapy on lipid metabolism in type 2 diabetic patients.Methods The subjects were composed of a normal group (n =400,195 males and 205 females),and a type 2 diabetic patients group (n =193,108 males and 85 females) which was further divided into normal lipid (n =33),hypercholesterolemia (n =21,TC ≥ 5.18 mmol/L),hypertriglyceridemic (n =53,TG ≥ 1.7 mmol/L),combined hyperlipidemia (n =75),and low high-density lipoprotein-cholesterol(n=11,HDL-C＜ 1.04 mmol/L) subgroups.The pre-and post-treatment levels of sdLDL-C and the influence of insulin therapy on lipid metabolism in type 2 diabetic patients (n =122,70 males and 52 females) were compared.Serum concentrations of sdLDL-C (sdLDL-EX SEIKEN reagent),triglyceride (TG),total cholesterol (TC),and fasting plasma glucose (FPG) were measured by automatic biochemical analyzer,fasting insulin and C-peptide were determined by chemiluminesence immunoassay,TG/HDL-C,sdLDL-C/ LDL-C,LDL-C/HDL-C,apoB/apoA Ⅰ,and other parameters were calculated.Results Compared with diabetic normal lipid group,the levels of sdLDL-C in hypercholesterolemia,hypertriglyceridemic,and combined hyperlipidemia subgroups were significantly higher(P＜0.05),the levels in combined hyperlipidemia subgroup were the highest.The levels of sdLDL-C in low high density lipoprotein cholesterol group showed no significantly difference (P＞0.05).While compared with normal group,the levels of sdLDL-C,TG,TC,LDL-C,ApoB,sdLDL-C/LDL-C,TC/HDL-C,TG/HDL-C,LDL-C/HDL-C,apoB/apoA Ⅰ,CRP,and HOMA-IR in type 2 diabetic patients were significantly higher(P＜0.05).Compared with pre-treatment group,the levels ofTG,TC,LDL-C,sdLDL-C,sdLDL-C/LDL,TC/HDL-C,TG/HDL-C,LDL-C/HDL-C,and apoB/apoA Ⅰ in post-treatment group were significantly lower(P ＜ 0.05).Conclusions sdLDL-C is the important indicator of lipid metabolism in type 2 diabetes,particularly in evaluating the changes in LDL particles.Insulin therapy is effective both in blood glucose control and improvement of dyslipidemia.Important information of clinical risk of dyslipidoses in type 2 diabetic patients provided by TG/HDL-C,LDL-C/HDL-C,sdLDL-C/LDL-C,and apoB/apoA Ⅰ ratios should be recognized and implemented in future clinical guidelines. Key words: Small and dense low-density lipoprotein-cholesterol ; Diabetes mellitus, type 2 ; Insulin ; Lipid metabolism