Roles of hepatic lipase and cholesteryl ester transfer protein in determining low density lipoprotein subfraction distribution in Chinese patients with non-insulin-dependent diabetes mellitus

Patients with non-insulin-dependent diabetes mellitus (NIDDM) are known to have abnormalities in their low density lipoprotein (LDL) subclass pattern with a preponderance of small dense LDL. The present study was performed to define the roles of lipolytic enzymes hepatic and lipoprotein lipase) and cholesteryl ester transfer protein (CETP) in determining the distribution o f LDL subfractions in these patients. LDL subfractions were measured by den sity gradient ultracentrifugation in 137 patients with NIDDM (75 male, 62 f emale) and 140 matched controls (80 male, 60 female). The male diabetic pat ients had a lower concentration of LDL-I (P < 0.01) and a higher concentrat ion of LDL-III than the controls (P < 0.01). In the female diabetic patient s, both LDL-I (P < 0.001) and LDL-II concentrations (P < 0.05) were signifi cantly lower than the controls whereas LDL-III was increased (P < 0.001). H epatic lipase (HL) was significantly increased in both the male and female diabetic patients (P < 0.01. P < 0.05, respectively) compared to their cont rols. No significant changes were seen in plasma lipoprotein lipase (LPL) a nd CETP activity. On multivariate analysis, plasma triglyceride (TG), CETP and HL accounted for 10, 5 and 3% of the variability in LDL-III, respective ly, in the diabetic patients (adjusted R-2 = 0.18, P = 0.0003), Our finding s would support the hypothesis that plasma triglyceride influences LDL part icles through a cycle of lipid exchange via the action of CETP. LDL become enriched in triglyceride and are then acted on by HL to produce a populatio n of small dense lipid-poor LDL. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.