人体冠状动脉粥样硬化斑块中氧化低密度脂蛋白和新生血管与斑块稳定性的关系

目的探讨氧化低密度脂蛋白(oxLDL)在人体冠脉稳定斑块和不稳定斑块内的分布、与血管新生之间的关系及其在不稳定斑块形成过程中的可能作用。方法选取经临床和病理解剖检查确诊的急性冠脉综合征(ACS)病例进行免疫组织化学SABC法染色并通过计算机图像分析系统进行量化分析。结果(1)不稳定斑块组内各部位oxLDL的聚集程度均明显高于稳定斑块组。oxLDL主要分布于斑块的肩部,纤维帽及基底部相对较少。oxLDL阳性面积比(‰)分别为肩部:不稳定斑块组20.43±3.12,稳定斑块组17.65±4.22;基底部:不稳定斑块组5.65±1.65,稳定斑块组3.22±1.02;纤维帽:不稳定斑块组4.77±2.03,稳定斑块组2.80±0.22。oxLDL是脂质核心的主要组成部分。(2)斑块肩部Ⅷ因子与oxLDL的阳性面积比呈明显正相关(r=0.8247,P=0.000)。结论不稳定斑块组较稳定斑块组oxLDL的聚集量高,尤其是肩部oxLDL的分布明显高于稳定组,提示斑块内oxLDL含量的多少及分布区域是影响斑块稳定性的重要因素。oxLDL通过促进炎细胞经新生血管在斑块局部聚集而影响斑块的稳定性。

Relationship between oxidized lipoprotein, angiogenesis and human coronary atherosclerotic plaque stabilization

OBJECTIVES: To analyze the relationship between oxidized low density lipoprotein (oxLDL), angiogenesis and stabilization of atherosclerotic plaques in human coronary arteries; and to investigate the role of oxLDL in creating vulnerable sites in atherosclerotic plaques. METHODS: Samples of coronary arteries were obtained at autopsies of 42 patients with acute coronary syndrome. Eighty randomly selected blocks were studied by immunohistochemistry using antibodies against oxLDL and endothelial cells (factor VIII). Computer-aided planimeter was used for quantitative analysis. RESULTS: In unstable plaques, percentage of immunoreactive areas for oxLDL was significantly higher than that in stable plaques. Most of the oxLDL were located in shoulder region of these plaques, as compared to the fibrous cap and basal regions. The details of distribution of oxLDL were as follows: shoulder region (20.43 +/- 3.12 for unstable plaques and 17.65 +/- 4.22 for stable plaques), fibrous cap (4.77 +/- 2.03 for unstable plaque and 2.80 +/- 0.22 for stable plaques) and basal region (5.65 +/- 1.65 for unstable plaques and 3.22 +/- 1.02 for unstable plaques). OxLDL was also a main component in the lipid core. In the shoulder region, there was a significant positive correlation between neovascularization and oxLDL (r = 0.8247, P = 0.000). CONCLUSIONS: The amount of oxLDL is significantly higher in unstable atherosclerotic plaques, especially over the shoulder region. OxLDL in coronary atherosclerotic plaques is thus an important factor in determining stabilization of the plaques. OxLDL may induce influx of inflammatory cells which subsequently leads to decreased plaque stabilization.