| [Background]Coronary heart disease (CHD) is an ischemic heart disease caused by atherosclerotic angiostenosis of coronary arteries. In recent years, as a major cause of death in China and in the developed countries, CHD has become a hotspot in cardiovascular study.Pathogenesis of atherosclerosis is recognized as chronic inflammatory response resulted from injured endothelium and collection of lipid at loci. It has demonstrated that intercellular adhesion molecules (ICAMs) and vascular cell adhesion molecules (VCAMs) were expressed by endothelial cells when endothelium was injured by risk factors of atherosclerosis. Monocytes began to adhere to endothelial cells and release chemokines and cytokines such as IL-6, IL-8and IFN-y that increase the quantity of inflammatory cells and induce platelet aggregation and release of thrombocyticgranule. By this way, the development of atherosclerosis is accelerated. Tumor necrosis factor-like weak inducer of apoptosis(TWEAK) discoved recently was reported that TWEAK is a potential mediater of chronic inflammation and be involved in the pathophysicial process of atherosclerosis.TWEAK is one of the members of tumor necrosis factor(TNF)super family. Its gene locats at chromosome17p13.1in human. TWEAK is initially expressed as a membrane-bound protein (mTWEAK) and subsequently proteolysed into a soluble form (sTWEAK). Both of two forms functoins similarly. While the development of atherosclerosis, TWEAK gene can be expressed by endothelial cells, macrophages and vascular smooth muscle cells (VSMCs). Through interaction with its cognate receptor FGF-inducible14kD protein (Fn14), TWEAK activates the signaling NF-κB and induce the expression of ICAMs and VCAMs in endothelial cells, results in the proliferation and migration of VSMCs and increase the expression of chemokines and cytokines in macrophages. Moreover, matrix metalprotonases (MMPs) induced by TWEAK degradate the fibrin in dense fibrous cap and cause the destabilization of atherosclerotic plaque, which results in the onset of acute myocardial infarction. Therefore, TWEAK is presumably a risk factor of AMI. Furthermore, when endothelial cell injured and blood platelets aggregate, the latter release granules which contain sTWEAK. The released sTWEAK act on endothilium and accelerate the adhesion of blood platelets and macrophages. This results in the expansion of the scale of endothelial dysfunction.Studies showed that recombined TWEAK could increase the size of atherosclerosis plaque in ApoE-gene knockout hyperlipemic mouse compared to that in control group. In contrast, TWEAK antibody could diminish the size of atherosclerosis plaque in ApoE-gene knockout hyperlipemic mouse. Advanced study shows the upregulation of proliferation of VSMC and Endothial cells induced by TWEAK. It was demonstrated a significant difference of sTWEAK serum expression in heart dysfunction and aneurysm. However, study of the association between sTWEAK and CHD is insufficient. We perform this study to observe the expression of sTWEAK among3clincial typing of CHD, to explore the correlation between sTWEAK and AMI onset, and to estimates the prognose of CHD by sTWEAK. [Objective]To explore the difference of expression of serum sTWEAK level in patients with CHD. To evaluate the association between sTWEAK and AMI onset and to explore the association between sTWEAK serum level and severity of CHD. To analyze the influence of sTWEAK level on long-term outcome in patients with CHD.[Methods]1. Objective1.1Design and Grouping1.1.1From June2008through January2010,217patients with CAD diagnosed by angiophotography admitted by Department of cardiology of General Hospital of Guangzhou Military Command of PLA were recruited and assigned into3groups according to the types of CHD (AMI=78cases; UAP=111cases SAP=28cases).All patients underwent coronary angiophotography and were diagnosed as CHD associated with clinical symptoms and examination. And30individuals who were confirmed suffering from no CHD servered as control group. The difference of sTWEAK serum levels among4groups was analyzed.1.1.2To study the association between clinical indicator and serum sTWEAK level; to study the relation between sTWEAK and severity of CHD and to explore the persumable risk factor of AMI.1.1.3217patients with CHD were cut into sTWEAK high level group and low level group according tocutoff in ROC curve to evaluate the association between sTWEAK and cardiovascular events. To evaluate the potential prognostic value of sTWEAK serum level for cardiovascular events on patients with CHD.1.2Exclusions:Individuals were excluded out of our study when it was accompanied with following diseases that influence on the expression of serum sTWEAK level reported by present literatures:I Autoimmune diseases and treated with immunosuppresant:such as systemic lupus erythematosus, systemic sclerosis, polyarteritis, colonitis and dermatitis;Ⅱ Acute necrosis of organs and tissues like stroke etc..Ⅲ Infectious diseases such as sepsis, acute pneumonia, acute hemorrhagic necrotic enteritis;Ⅳ Malignant neoplasms;Ⅴ Chronic kidneys diseases or kidney injuries such as nephrotic syndrome, glomerular nephritis, chronic kidney dysfunction;Ⅵ Peripheral vascular disease;Ⅶ Disorders of blood coagulation or hemolytic disease;Ⅷ Heart dysfunction, brain natriuretic peptide (BNP)>1000pg/ml, and ejection fraction(EF)<40%;Ⅸ Ischemic heart disease caused by tachyarrhythmia, cardiomyopathy etc.Ⅹ Heart operation in recent.2. Methods2.1Blood samples:11ml venous blood was collected at the next day of admission. The blood sample was stayed for10minutes and serum sample was exacted and stored in aliquots at-80℃till quantification of sTWEAK.2.2Serum sTWEAK assay:Serum sTWEAK level was quantitatively detected by commercial available enzyme-linked immunosorbent assay (ELISA) of human TWEAK (Bender MedSystems GmbH, Wien, Austria, LOT:64629026) according to the manufacturer’s instructions. Briefly,100μl distilled water was added to all standard and blank wells as indicated on the label of the standard strips and to sample wells. Then50μl serum samples were added to the designed wells. Thereafter ELISA plate was incubated at room temperature for3hours on a microplate shaker at 200rpm. Microwellstrips were washed with400μl buffer per well for6times and100μl TMB substrate solution was pipetted to all wells. After10minutes incubation at room temperature in the dark, the substrate reaction was stopped as soon as standard1had reached an OD of0.9-0.95. Finally, Absorbance was measured with an automatic ELISA reader (2000, USA). Human sTWEAK is detected with this kit at a threshold of pg/ml. Intra-assay and inter-assay coefficients of variation were8.8%and1.2%, respectively.2.3Gensini score:According to coronary angiophotographic appearance of concentric lesions and eccentric plaques resulting in, respectively,25,50,75,90and99%obstruction as well as complete occlusion (100%). The relative severity of these lesions using a score of1for25%obstruction and doubling that number as the severity of th obstructions progresses according of the indicated reduction of lumen diameter the principal vascular segments of the right coronary artery, the left anterior descending and the circumflex, each segment is followed by a multiplying factor such as x1, x2.5and so on depending on the functional significance of the area supplied by that segment. Product of the score and the factor is the score of the segment with obstruction. Finally, sum of the scores of all obstruction segments is the Gensini score.2.4Follow-up:All patients with coronary heart disease in our study were followed by front-to-front or telephone for2year after first admission. In our study, cardiovascular adverse events were defined as cardiovascular death, AMI and admission-necessary angia pectoris.2.5Other indicators:The results of serum level of LDL-C, HDL-C, total cholesterol, triglyceride, apolipoprotein A I, lipoprotein (a) were gained from blood biochemical asssay in our hospital.3. Statistics:SPSS software version19.0(SPSS, IBM) was used for all statistical analyses. Data were described in (x±s) or proportion in percentage. Difference of serum sTWEAK concentrations among groups were assessed by one-way ANOVA Welch test. Multiple comparations among groups were analyzed by Tamhane method. Correlations were estimated by Spearman’s correlation analysis and partical correlation. Logistic regression analyses were performed to evaluate the risk factor of covariates.Roc curve and product-limited method (Kaplan-Meier method) was performed to analyze the outcome of disease. Chi-square test was performed to compare incidences of adverse events. A p-value<0.05was considered as statistically significance in all analyses.[Results]1. The mean of the serum sTWEAK concentration in AMI group ranged (1303.081±505.115) pg/ml, whereas in UAP group (876.353±391.922) pg/ml, in SAP group (795.973±385.031) pg/ml and in control (810.352±260.255) pg/ml. sTWEAK level is significantly increased in AMI group in comparison with that in UAP and SAP group(P<0.001respectively). No significant difference among UAP, SAP group and control group was found in multiple comparation by Tamhane method (P>0.05respectively).2. In patients with CHD, Serum sTWEAK level was associated with Gensini score(r=0.432, P<0.001). No association was found between sTWEAK and CRP.TG, TC, ApoA I, LDL-c, HDL, Lp(a)(P>0.05).3. In patients with AMI, Serum sTWEAK level was associated with Gensini score(r=0.535. P<0.001). No association was found between sTWEAK and CRP,TG, TC, ApoA I, LDL-c, HDL, Lp(a)(P>0.05).4. sTWEAK and LDL-c were associated with AMI.(sTWEAK:OR=1.003, P=0.003,95%CI=1.001-1.004; LDL-c:OR=3.279, P=0.020,95%CI=1.201-8.951). 5. Roc curve was performed to estimate cardiovascular events by sTWEAK serum level, AUC=0.650P=0.009. cutoff=951.183pg/ml(sensitivity0.759; specificity0.638). Incidence of cardiovasvular events in sTWEAK high level group is significantly increased in comparison with that in sTWEAK low level group (χ2=16.307, P<0.001).6. Patients exposed to high level sTWEAK showed the recurrence of adverse cardiovascular event at(20.228±0.863)months, whereas patients exposed to low level sTWEAK showed the recurrence of adverse cardiovascular event at (23.291±0.318) months. The patients exposed to high level sTWEAK had an increasing risk of cardiovascular adverse events compared to those exposed to low level sTWEAK (log-ranktest:χ2;=19.862;P<0.001).[Conclusions]1. Serum sTWEAK level in patients with AMI is significantly increased compared to that in UAP and SAP group.2. In patients with CHD and in patients with AMI, serum sTWEAK level is positively associated with Gensini score. CRP and blood fat indicators are not relative to serum sTWEAK level.3. sTWEAK and LDL-c are relative to AMI.4. Serum sTWEAK level has a potential value to predict the cardiovascular events in patients with CHD. |
