RESUMO
OBJECTIVE: To explore the relationship between the severity of cardiovascular disease with the expression of apolipoprotein(a) [apo(a)] and apolipoprotein B (apoB) in peripheral blood and their location in peripheral blood cells. METHODS: In this report, we selected 4 patients with angiography which indicated that three coronary arteries were narrowed and 5 control patients with normal angiography. Arterial blood was collected and analyzed for lipid parameters in plasma. The mRNA expression of apo(a) and apoB in peripheral white blood cells and platelets were determined by RT-PCR and their protein expression by western blot. Moreover, the expression and location of apo(a) and apoB in white blood cells were determined by confocal microscopy and computer 3D analysis. RESULTS: In plasma, levels of high density lipo-protein-cholesterol (HDL-C) and polipoprotein A-I(apoA-I) in cardiovascular disease (CVD) patients were significantly less than those in the control patients[(0.62+/-0.05) mmol/L, (0.78+/-0.08) mmol/L vs (0.81+/-0.15) mmol/L, (0.9+/-0.07) mmol/L, P<0.05], but the concentration of other plasma lipid parameters was not different. The size of apo(a) isoforms was not reversely related to the severity of cardiovascular disease and the most commonly occurring phenotype of apo(a) was S4.The expression of apoB in platelets in cardiovascular disease patients was less than that in the control patients by 25.1% (optical density value 0.67+/-0.18 vs 1.00+/-0.10, P<0.05),but the expression of apo(a) was not different between the two groups (optical density value 0.43+/-0.18 vs 0.61+/-0.40, P>0.05). Studies with confocal microscopy indicated that proteins of apo(a) and apoB were co-expressed by a few cells of leukocytes and the ratio of apoB/apo(a) in cardiovascular disease patients was significantly less than that in the control patients (optical density value 1.60+/-0.12 vs 4.40+/-0.35, P<0.05). In platelets and leukocytes, mRNA of apo(a) or apoB was not detectable. CONCLUSION: Our studies indicate that peripheral blood cells can carry apo(a) and apoB, furthermore the contents of apoB and apo(a) in cells are different between cardiovascular disease patients and patients with normal coronary artery.