Cellular processing of apolipoprotein B-containing lipoproteins from young post-infarction patients and healthy controls.
3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity was measured in fibroblasts incubated with large (Sf > 60) and small (Sf 20-60) very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL) and low density lipoprotein (LDL) particles, at similar protein concentrations, from young post-infarction patients and healthy controls. The results showed that apolipoprotein (apo) B-containing lipoproteins (VLDL, IDL, LDL) from patients suppressed HMG-CoA reductase activity to a similar extent compared to apo B-containing lipoproteins from controls. When all subjects taken together were grouped according to triglyceride levels, it was found that small VLDL from hypertriglyceridaemic individuals suppressed the HMG-CoA reductase activity more than small VLDL from normotriglyceridaemic individuals. The opposite pattern was seen for LDL. The lipoprotein composition was related to the respective HMG-CoA reductase activity. In addition to a positive association between the cholesterol content of small VLDL and LDL, and the inhibition of HMG-CoA reductase activity, the apo C I and C II content of small VLDL and IDL was inversely related to the suppression of HMG-CoA reductase activity. This study shows that the cellular processing of apo B-containing lipoproteins in young post-infarction patients and healthy controls is heterogeneous and dependent on the composition of the lipoprotein.
D000328:Adult; D001055:Apolipoproteins B / Q000378:metabolism*; D001057:Apolipoproteins E / Q000378:metabolism; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008074:Lipoproteins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000378:metabolism*
D001055:Apolipoproteins B; D001057:Apolipoproteins E; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008074:Lipoproteins; D006903:Hydroxymethylglutaryl CoA Reductases