冠心病患者外周血中载脂蛋白(a)和载脂蛋白B的表达和定位

Location and expression of apo(a) and apoB in peripheral blood of patients with cardiovascular disease

目的:研究冠心病患者的血浆和外周血细胞中载脂蛋白(a)[apolipoprotein(a),apo(a)]和载脂蛋白B(apolipoprotein B,apoB)的表达变化及其在外周血细胞中的定位。方法:选择经冠状动脉造影诊断为冠心病且为三支病变的患者4例(A组)及冠状动脉造影正常对照者5例(B组)。采集其外周动脉血检测血浆脂质水平,RT-PCR方法检测外周血白细胞和血小板中apo(a)和apoB的mRNA表达,Western blot方法检测apo(a)和apoB在血浆、外周血白细胞和血小板中的蛋白表达及血浆apo(a)蛋白表型,并用激光共聚焦荧光显微镜及计算机三维成像技术分析外周血白细胞中apo(a)和apoB蛋白定位和含量。结果:冠心病患者与冠状动脉正常者相比,血浆高密度脂蛋白胆固醇(high density lipoprotein cholesterol,HDL-C)水平明显降低[(0.62±0.05)mmol/L比(0.81±0.15)mmol/L,P<0.05],载脂蛋白A-Ⅰ(apolipoprotein A-Ⅰ,apoA-Ⅰ)水平亦明显降低[(0.78±0.08)mmol/L比(0.9±0.07)mmol/L,P<0.05],但血浆其他脂质水平差异无统计学意义。本研究并未发现apo(a)低相对分子质量亚型与冠状动脉病变相关,血浆apo(a)表型以S4为主。冠心病患者外周血血小板中apoB的蛋白水平比冠状动脉正常者减少25.1%(光密度值为0.67±0.18比1.0±0.1,P<0.05),但apo(a)表达在两组之间差异无统计学意义(光密度值0.43±0.18比0.61±0.4,P>0.05)。用激光共聚焦荧光显微镜观察到白细胞中apo(a)和apoB共定位,冠心病患者apoB/apo(a)比值较冠状动脉正常者显著降低(光密度值1.60±0.12比4.4±0.35,P<0.05)。但外周血白细胞和血小板中并未检测到apo(a)和apoB mRNA的表达。结论:外周血白细胞和血小板可携带载脂蛋白apo(a)和apoB,并且其含量在冠心病患者与冠状动脉正常者间存在差异。

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 angiogra- phy. 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 pro- tein 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 apolipoprotein 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：Ourstudies 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.