The Study Of The Relationship Between High Sensitive C-reactive Protein And Atherosclerotic Progression

Inflammation seems to play a critical role in all stages of atherosclerosis, from the nascent lesion to acute coronary syndromes (ACS) . Oreactive protein (CRP) is a marker of inflammation, and a numerous prospective studies have proved that high sensitive C-reactive protein (hs-CRP) can predict both cardiovascular events (CVE) in apparently healthy persons and a poor prognosis in patients with ACS. ACS, the main type of coronary heart disease, is of high mortality and severely threats the health of people. Rupture of the unstable plaque with subsequent thrombus formation is the common pathophysiological substrate of ACS, so identified the unstable plaque is important in the therapy of ACS. Inflammatory response plays an important role in the onset, development, and evolution of atherosclerotic lesions. Inflammation factors are of critical role in the advancement of atherosclerosis. CRP is the sensitive marker of inflammation. hs-CRP is elevated in coronary heart disease and elevated most significantly in acute myocardial infarction, and then in unstable angina and the least in stable angina. Hs-CRP was positive associate to the severity of the coronary artery atherosclerosis. Studies have demonstrated that hs-CRP is the independent risk factor of coronary heart disease in the normality and the independent factor of prognosis in patients with coronary heart disease. Hs-CRP is not only the inflammation factor, but also maybe participate in the the onset, development, and evolution of atherosclerosis. Therefore we investigated the relationship between hs-CRP, associated inflammatory factors and coronary plaque morphology by intravascular ultrasound (IVUS) , and the mechanism of CRP induced apoptosis of human endothelium cells in vitro.Part I The study of high sensitive C-reactive protein (hs-CRP) and associated inflammation factors in evaluating the type of coronary artery atherosclerotic plaqueBackground Rupture of unstable plaque with subsequent thrombus formation is the common pathophysiological substrate of ACS. It is of potential significance to explore the blood indexes predicting for plaque characteristics. Little studies have focused on this field. Therefore we investigated the relationship between hs-CRP, promatrix metalloproteinase-1 (ProMMP-1), tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), interleukin 1 (IL-1), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and the characteristics of coronary artery atherosclerotic plaque to explore the specific laboratory index to reflect the type atherosclerotic plaque.Methods Coronary angiography and intravascular ultrasound (IVUS) were examined to explore the characteristics of coronary artery atherosclerotic plaque in patients with coronary heart disease before percutaneous coronary intervention. Plasma samples of arterial blood were collected prior to the procedure. The level of hs-CRP, ProMMP-1 and TIMP-1,IL-1, IL-6, TNF-a were respectively measured by enzyme-linked immunosorbent assay (ELISA).Results In most of acute myocardial infarction and unstable angina, and ruptured plaque was more frequently found in acute myocardial infarction, while stable angina were presented mostly with stable plaque. External elastic membrane cross-sectional area (EEM CSA),plaque area,plaque burdenm, lipid pool area and lipid pool burden were significantly larger in ruptured and unstable plaque group. Positive remolding, thinner fabric-cap, smaller minimal lumen cross-sectional area (MLA), dissection and thrombus were significantly more frequent in ruptured and unstable plaque group. The level of hs-CRP was highest in ruptured plaque group and then in unstable plaque group, it was lowest in stable plaque group. ProMMP-1 and TIMP-1 were higher in ruptured plaque group than these in unstable and stable plaque group, but there was no significant difference between unstable and stable plaque group. IL-1 and IL-6 were higher in ruptured and unstable plaque group, but there was no difference between ruptured and unstable plaque group. TNF-α was higher in ruptured groupthan that in stable plaque group, there was no difference between these two groups and unstable group. hs-CRP>8. 94mg/L was used to reflect the ruptured plaque with sensitivity of 71.80%, specificity of 77.00% and accuracy of 69.20% (p < 0.0001), similarly sensitivity of 69.20%, specificity of 75.20% and accuracy of 66.20% for ProMMP-l> 0. 12ng/mL (p <0.0001); sensitivity of 66.70%, specificity of 61.90% and accuracy of 66.20% for TIMP-1> 83.45ng/mL (p= 0.001); sensitivity of 64.1%, specificity of 68. 1% and accuracy of 64. 1% for IL-6> 3. 83ng/mL (p < 0. 001) ; but there were no value for IL-1 and TNF- α . hs-CRP>5. 22mg/L was used to reflect the high risk plaque with sensitivity of 81.6%, specificity of 78. 9% and accuracy of 81. 6% (p < 0. 0001) ; similarly sensitivity of 59. 20%, specificity of 53. 9% and accuracy of 55. 7% for ProMMP-1> 0. 59ng/mL (p < 0. 0001) ; sensitivity of 60. 5%, specificity of 60. 5% and accuracy of 60. 5% for TNF- α > 14. 86ng/mL (p = 0. 008) ; sensitivity of 64. 5%, specificity of 67.1% and accuracy of 64.47% for IL-1>8.59ng/mL (p < 0.001); and sensitivity of 72.4%, specificity of 76.3% and accuracy of 71.05% for IL-6>3. 54ng/mL (p < 0.001); but there were no value for TIMP-1. Conclusion There is a relationship between clinical presentation of coronary heart disease and plaque characteristics; The elevation of hs-CRP, ProMMP-1, TIMP-1 IL-1, IL-6 and TNF-α are related to the plaque instability and rupture; The elevation of hs-CRP, ProMMP-1, TIMP-1 and IL-6 may reflect the ruptured plaque; The elevation of hs-CRP, ProMMP-1, IL-1, IL-6 and TNF-α may reflect the high risk plaque.Part II Expression of Bcl-2/Bax gene in c-reactive protein inducedapoptosis of human endothelium cells in vitroObjective C-reactive protein (CRP) has been suggested to actively participate in the development of atherosclerosis, in the present study, we examined the expression of Bcl-2/Bax protein in c-reactive protein (CRP) induced apoptosis in human endothelium cells in vitro. Methods The human umbilical vein endothelial cells (HUVEC) were cultured by digest method for 2-3 posterities. HUVECs were incubated with human CRP (0-25Mg/mL for 24 hours) and analyzed by flow cytometer for apoptosis ratio. The effects of CRP on Bcl-2/Bax mRNA and protein expression were examined by the techniques of RT-PCR and Western blotting. Results Compared to the control group, the apoptosis ratio of HUVECs was maximal in 25μg/mL group (15. 71 ±2. 34%) (P<0. 01) after incubated with CRP for 24h. In the same concentration CRP caused a marked down-regulation of BCl-2 mRNA and protein expression which promotes cell survival, and up-regulation of Bax mRNA and protein expression which promotes apoptosis after incubation with CRP for 4,8h.Conclusion These results demonstrate that Bcl-2\Bax is a CRP-regulated gene and proteinin human HUVECs and plays a causal role in CRP-induced apoptosis. Pharmacological targeting of CRP expression or action may provide a novel therapy for atherosclerosis.