| BackgroundAtherosclerosis is one of the major diseases which are harmful to human health. Atherosclerosis is the basic pathophysiology of coronary heart disease. Current researches show that atherosclerosis pathogenesis is a complex, integrated, long-term process. Vascular endothelial dysfunction and unremitting inflammatory reaction are key factors which caused the occurrence and development of atherosclerosis and resulted in acute coronary syndrome. Acute coronary syndrome is a group of clinical syndrome which is based on the pathological basis of thrombosis occlusive of the complete or incomplete which is secondary to coronary atherosclerotic plaque rupture or erosion. Inflammatory reaction plays a critical role in the process of happen, evolution. and the breakdown of instable plaque in ACS.Coronary stenting is an effective method which treats acute coronary syndrome, which can rapidly restore coronary blood flow to save the dying cadiocyte. But the in-stent restenosis rate was up to 20%-30%. and seriously affected the long-term prognosis of these patients. Mechanism of in-stent restenosis is complicated, but it is generally considered that it is a local over-reaction to vascular mechanical injury for repair. Stent as a extraneous material can stimulated the vessel wall, as well as intimal injury caused by surgery, coronary plaque rupture, leaded to platelet aggregation and inflammatory cell infiltration, the release of inflammatory mediators, chemokines, adhesion molecules and growth factors, which promoted migration and proliferation of vascular smooth muscle cells(SMC) and adventitial fibroblasts, resulting in in-stent restenosis. Inflammatory reaction after stent implantation is one of important cause which led to in-stent restenosis.Syndecan-4 is a transmembrane heparan sulfate proteoglycan belonging to the syndecan family. Syndecan-4 protein is encoded by four independent genes with tissue-specific distribution of type I integral membrane protein. The protein has a molecular weight of about 24KDa, which contains 197 amino acid sequence and is bonded by a long Glycosaminoglycan(GAG) chains and core protein through covalent. GAG chain belongs to heparan sulfate (HS) type, this HS structure is involved in action of syndecan-4 binding ligand and regulates their activity. Current researches have shown that syndecan-4 regulates a wide range of biological effects, and plays an important role in signal transduction of the cell surface system and control of cell behavior (such as: mechanical support of cell, cell adhesion, movement, proliferation, differentiation and the formation of patterns),etc.The function of syndecan-4 in blood vessel include: to maintain viscoelasticity, permeability and the integrity of the vessel wall and to prevent vessel contents is lost and the vessel wall is infiltrated. as a "co-receptor" , syndecan-4 play an important role in regulating a variety of inflammatory mediators in the acute phase and late of tissue injury. The result that syndecan-4 combined with mediators which were expressed and secreted by normal T cell and stromal cell-derived factor-1 influenced the accumulation of leukocytes. However,at present,there is no report about the relationship between coronary artery stenting and the levels of syndecan-4 protein. In our study, we measured plasma concentrations of syndecan-4 protein of patients with acute coronary syndrome at pre-stenting and post-stenting at 1hour and 24 hours respectively in order to understand further the change of plasma levels of syndecan-4 protein before and after coronary stenting.ObjectiveTo observe the effects of coronary stent implantation (CSI) on plasma levels of syndecan-4 protein in patients with acute coronary syndrome.Methods1,A total of 43 patients who were angiographically confirmed acute coronary syndrome and underwent successfully coronary stent implantation were recruited from October 2007 to October 2008 at Nanfang hospital. Except for those who have the following cases:①there is a serious infection;②patients with liver and kidney function seriously damaged;③patients with malignant tumors;④patients with systemic diseases of the immune system, connective tissue diseases;⑤patients with a variety of inflammatory diseases;⑥patients with rheumatic heart disease, cardiomyopathy, myocarditis, congenital heart disease;⑦there is a history of stroke in recent six month, there is trauma,infection and surgical history in recent three month;⑧patients selected for angiography with cardiac function grade II NY class or less. Blood samples were collected pre-stenting and post-stenting at 1hour and 24 hours respectively, and 11 patients with normal angiography as the control group. The plasma levels of syndecan-4 protein in patients were measured by enzyme-linked immuno-sorbent assay(ELISA).2,Some baseline characteristics of coronary stent implantation group and contol group (age, sex, smoking, blood pressure, plasma sugar, plasma lipid, medication, LVEF, CRP, etc.)were collected for a statistical description,and some of them were compared.3,Values were expressed as mean±S.D. Comparisons between two groups were performed using a Student's unpaired t-test for continuous variables and a chi-square test for categorical variables. Serial changes in the variables were evaluated by repeated measures analysis of variance (ANOVA), p-value<0.05 were considered significant. All analysis was performed using SPSS software, Version 13.0 for Windows.Results1,There were no statistical differences in some baseline characteristics(age, sex, smoking, blood pressure, plasma sugar, plasma lipid, etc.) except CRP between CSI group and control group (P>0.05).However, there was statistical difference in CRP between two group(P<0.05),it is suggested inflammatory plays a important role in the acute coronary syndrome.2,There were significant differences in plasma levels of syndecan-4 protein in the CSI group at three different time points(P<0.05), the plasma concentrations of syndecan-4 protein increased significantly at 1 hour after coronary stenting comparing with that at pre-operation (P=0.004), the plasma concentrations of syndecan-4 protein decreased significantly at 24 hour after coronary stenting compared with that at pre-operation and 1 hour of post-operation. (P=0.000, P=0.026 ), In the CSI group, the plasma levels of syndecan-4 protein show the trend of rising first then declining. It can be seen that the plasma levels of syndecan-4 protein in patients with acute coronary syndrome can be significantly influenced by coronary stent implantation. There were no significant differences in plasma levels of syndecan-4 protein in the control group at three different time points (P>0.05) ,It is suggested that coronary angiography alone had no significant effect on plasma levels of syndecan-4 protein.3,Comparing the two groups at the same time,the plasma levels of syndecan-4 protein in the CSI group at 1 hour after stenting were significantly higher than that of the control group at 1 hour after angiography(P=0.023). However, statistical differences in plasma levels of syndecan-4 protein were not observed between the two groups at both pre-operation and at 24 hours of post-operation (P>0.05) .ConclusionsOur study suggests that coronary stent implantation can increase significantly plasma levels of syndecan-4 protein in patients with acute conoary syndrome. It is suggested that syndecan-4 may play an important role as a biological mediator in the mechanical damage repair and early inflammation reaction in vascular wall.
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