PLASMA APOLIPOPROTEIN A-I, A-II, B, E AND C-III CONTAINING PARTICLES IN MEN WITH PREMATURE CORONARY-ARTERY DISEASE

Lipoprotein (Lp) cholesterol and apolipoproteins (apo) A-I and B levels have been shown to be better markers for the presence of coronary artery disease than total cholesterol. In this study, we determined the plasma levels of lipoprotein particles containing apo A-I only (LpA-I), apo A-I and A-II (LpA-I:A-II), apo B and C-III (LpB:C-III) and apo B and E (LpB:E) in 145 patients with coronary artery disease (mean age +/- SD, 51 +/- 7 years) and 135 healthy control men (mean age 49 +/- 11 years). Patients with CAD had lower high density lipoprotein (HDL) cholesterol and apo A-I levels and higher triglycerides and apo B levels than controls. In patients with CAD, LpA-I (0.341 +/- 0.093 vs. 0.461 +/- 148 g/l) and LpA-I:A-II (0.694 +/- 0.171 vs. 0.899 +/- 0.148 g/l) were lower, whereas LpB:E (0.372 +/- 0.204 vs. 0.235 +/- 0.184 g/l) were higher than in controls (cases vs. controls, all P < 0.005). No significant differences were observed for LpB: C-III (0.098 +/- 0.057 vs. 0.107 +/- 0.061 g/l, p = 0.235) particles. Discriminant analysis indicates that LpA-II:A-I, LpE:B, LpA-I, and triglycerides best differentiate between cases and controls. Plasma apo C-III (0.027 +/- 0.008 vs. 0.036 +/- 0.020 g/l) and E (0.040 +/- 0.015 vs. 0.055 +/- 0.029 g/l) were lower in the CAD group (P < 0.001). The finding that apo C-III and E levels are lower in the CAD patients relate to the fact that in our patients, HDL particles are the main carriers of apo E and C-III and that in addition to HDL-cholesterol, the protein component of HDL particles are reduced in CAD. We conclude that apo B, LpB:E but not LpB:C-III containing particles are increased in patients with CAD and that apo A-I containing particles, with or without apo A-II are reduced in patients with CAD. In addition, HDL-cholesterol and associated apolipoproteins (A-I, A-II, C-III and E) are reduced in CAD.