- 作者：K-Raman Purushothaman ; Meerarani Purushothaman ; Andrew P. Levy ; Patrick A. Lento ; Solene Evrard ; Jason C. Kovacic ; Karen C. Briley-Saebo ; Sotirios Tsimikas ; Joseph L. Witztum ; Prakash Krishnan ; Annapoorna Kini ; Zahi A. Fayad ; Valentin Fuster ; Samin K. Sharma ; Pedro R. Moreno
- 关键词：apoptosis ; atherosclerosis ; haptoglobin genotypes ; iron ; oxidative stress
- 刊名：Journal of the American College of Cardiology
- 出版年：2012
- 出版时间：10 July, 2012
- 年：2012
- 卷：60
- 期：2
- 页码：112-119
- 全文大小：2714 K
Objectives
The purpose of this study was to test the hypothesis that increased oxidative stress is associated with apoptosis in human plaques with the haptoglobin (Hp) 2-2 genotype.Background
Intraplaque hemorrhage releases free hemoglobin (Hb). Impaired Hb clearance induces oxidative stress leading to plaque progression. The binding of Hp to Hb attenuates iron-induced oxidative reactions.
Methods
Twenty-six human aortic plaques were Hp genotyped. Hp2-2 plaques (n = 13) were compared with control (Hp1-1/2-1) (n = 13). The iron grade was measured by Perl's staining. Immunostaining was used to detect oxidation-specific epitopes (OSEs) reflecting oxidized phospholipids and malondialdehyde-like epitopes. The percentages of apoptotic cells and apoptotic morphological features were quantified. DNA fragmentation and active caspase-3 were measured by in situ end-labeling and immunohistochemistry, respectively.
Results
In Hp2-2 plaques, iron content was increased (1.22 ¡À 0.15 vs. 0.54 ¡À 0.08; p < 0.0001) along with expression of oxidized phospholipid- (78.9 ¡À 5.8 vs. 38.8 ¡À 3.8; p < 0.0001), and malondialdehyde-like OSEs (93.9 ¡À 7.9 vs. 54.7 ¡À 3.9; p < 0.0001). The total percentages of apoptotic cells (11.9 ¡À 0.44 vs. 3.5 ¡À 0.28; p < 0.0001), nuclear fragmentation (11.8 ¡À 0.50 vs. 3.3 ¡À 0.26; p < 0.0001), nuclear condensation (10.9 ¡À 0.58 vs. 3.4 ¡À 0.20; p < 0.0001), chromatin margination (14.2 ¡À 0.57 vs. 6.5 ¡À 0.37; p < 0.0001), cytoplasmic blebs (1.6 ¡À 0.28 vs. 0.8 ¡À 0.14; p < 0.002), and eosinophilia (10.8 ¡À 0.74 vs. 4.2 ¡À 0.27; p < 0.0001) were increased in Hp2-2 plaques. Furthermore, DNA fragmentation (119.9 ¡À 1.40 vs. 57.5 ¡À 0.80; p < 0.001), and active caspase-3 density (84.7 ¡À 7.62 vs. 50.6 ¡À 7.49; p < 0.004) were increased in Hp2-2 plaques. Logistic regression analysis identified correlation between the percentage of apoptotic cells and the density of OSEs (r = 0.56; p < 0.003).
Conclusions
These findings provide insights into genetic predisposition to oxidative stress and the relationship between OSEs and macrophage apoptosis that may explain advanced atherosclerosis in human Hp2-2 plaques.