Low density lipoprotein density and composition in hypercholesterolaemic men treated with HMG CoA reductase inhibitors and gemfibrozil

The effects of HMG CoA reductase inhibitor (lovastatin or simvastatin) and gemfibrozil treatment on low density lipoprotein (LDL) density distribution and composition were studied in male patients with heterozygous familial hypercholesterolaemia (FH) (n = 17) or non-familial hypercholesterolaemia (non-FH) (n = 14). In FH patients the HMG CoA reductase inhibitors reduced 'light' LDL particles (density 1.022-1.033 g ml-1) significantly more than 'heavy' LDL (density 1.033-1.059 g ml-1), while a more uniform reduction of 'light' and 'heavy' LDL occurred in non-FH patients. HMG CoA reductase inhibitor treatment increased the apolipoprotein B (apoB) content and decreased the cholesterol/apoB ratio of LDL in FH patients. Gemfibrozil significantly reduced 'heavy' LDL but not the 'light' LDL fraction in both FH and non-FH patients, and the mean cholesteryl ester content of LDL increased, while the Tg content decreased, in both FH and non-FH patients. The results indicate that HMG CoA reductase inhibitor and gemfibrozil treatment have distinctly different effects on the physico-chemical properties of LDL, reflecting their different modes of action on lipoprotein metabolism.