To study the effects of gemfibrozil treatment on LDL particle size, density distribution, and composition in NIDDM patients.
We performed LDL analyses on 16 NIDDM patients with stable glycemic control. They were randomly allocated to receive either gemfibrozil (n = 8) or a placebo (n = 8) for 3 mo in a double-blind study. The LDL particle size distribution and the particle diameter of the major LDL peak were measured with nondenaturing polyacrylamide gradient gel electrophoresis. The density distribution and composition of LDL were determined with the density gradient ultracentrifugation method.
In the gemfibrozil group the mean serum TG concentration decreased by 38%, HDL cholesterol concentration increased by 10%, and LDL cholesterol concentration by 17% (P < 0.05). During gemfibrozil therapy the mean particle diameter of the major LDL peak increased from 244 to 251 Å (P < 0.05), whereas in the placebo group the mean LDL particle diameter remained unchanged. We found an inverse correlation between the changes of serum TG and the particle diameters of the major LDL peak (r = 0.85, P < 0.01). Gemfibrozil produced a shift in the LDL density distribution toward lower density. The mean peak density decreased from 1.0371 to 1.0345 g/ml because of a significant rise in the light LDL concentration from 141.0 to 183.2 mg/dl (P < 0.05), whereas the concentration of dense LDL had a tendency to decrease. In the placebo group the LDL density distribution did not change. Gemfibrozil increased the CE-to-TG ratio in LDL core lipids by 27% (P < 0.05); otherwise, the LDL composition was only slightly affected.
The results indicate gemfibrozil-induced changes in LDL properties in NIDDM patients are similar to those previously reported in nondiabetic individuals and are related to changes in serum TG level.