[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.

[Angiogenesis in coronary atherosclerotic plaques and its relationship to plaque stabilization].

OBJECTIVE: To compare the angiogenesis in unstable and stable plaques and to investigate the potential role of neovessels in creating vulnerable sites for atherosclerotic plaques. METHODS: Specimens of coronary arteries were obtained from 52 autopsy cases with acute coronary syndromes. Plaque morphology was studied by use of stained slides. 922 tissue blocks of late-stage lesions were classified into two groups: (1) unstable plaque (n = 153), the plaque was characterized by a large extracellular lipid core (more than 40% of the plaque area); (2) stable plaque (n = 769), lipid core less than 40% of the plaque area. Forty blocks were selected randomly from each group and serial sections were stained immunohistochemically with a polyclonal antibody against F VIII RAg. Computer-aided planimeter was used for quantitative analysis. RESULTS: In unstable plaques, the occurrence of neovessels was more frequent and the neovessel density (number/mm(2)) was significantly increased as compared to that of stable plaques (frequency: 80.4% vs 66.6%, P < 0.01; shoulder: 22.16 +/- 19.96 vs 10.04 +/- 11.52, base: 21.68 +/- 20.44 vs 9.68 +/- 11.52, fibrous cap: 3.80 +/- 5.32 vs 1.48 +/- 2.28, P < 0.05). Most neovessels were located in the shoulder region and at the base of plaques. CONCLUSIONS: These findings suggest that neovessels in coronary atherosclerotic plaques are closely associated with the decreased stabilization of the plaques.