| Objective Numerous researches have suggested the change of TC level and LDL-C level as an important predictor for the onset of CHD,the increase of TC level as the major risk factor for atherosclerosis(AS),and the positive correlation between the increase of LDL-C and the onset of CHD.Our clinical working experiences suggest that a majority of acute myocardial infarction patients have a normal or declined lipid level(TC,TGand LDL-C) during the acute phase.Nevertheless,few studies have been carried out previously in China to explore the possible reason behind this phenomenon.In the process of normal lipid metabolism process,2/3 LDL is degraded through LDL receptor,while the other 1/3 is eliminated by the macrophage within the net-shaped endothelial cells system.Besides,numerous basic and clinical studies in recent years have reported atheroma/atherosclerosis as a disease driven by a chronic inflammation in blood vessels,and inflammation plays a critical role during the formation,evolution and breaking of atherosclerotic lesion. This dissertation conducts a retrospective analysis on the lipid level in myocardial markers positive patients,aming to find the different lipid levels among 3 groups, namely,Acute Myocardial Infarction(Group AMI),Unstable Angina Pectoris(Group UAP) and Stable Angina Pectoris(Group SAP).It also explores effects of Tumor Necrosis Factor-α(TNF-α) on macrophage's phagocytosis of LDL and ox-LDL and the potential mechanism of the declined lipid level after the onset of acute myocardial infarction(AMI) in order to offer basic evidences for the prevention,diagnosis and treatment of CHD.Methods 1.It conducts a retrospective study of 1593 Coronary Heart Disease(CHD patients hospitalized in cardiovascular department of Tianjin Pectoral Disease Hospital from July,2006 to October,2007 and from November,2007 to December, 2008.It also classified the patients,according to Universal Definition of Myocardial Infarction,the new diagnosis standard recommended by domestic experts in Oct, 2008 and diagnosis standard for the angina pectoris,into 3 groups,namely,564 cases into AMI,780 cases into Unstable Angina Pectoris(UAP) and 249 cases into Stable Angina Pectoris(SAP).12h fasting blood samples are taken and sent to Clinical Laboratory for such examinations as TC,TG,HDL-C,LDL-C,VLDL-C,ApoA I, ApoB,LP(a),blood routine and hemostasis;then,Record the general clinical data.2.The author of the dissertation also nurtures THP-1 Monocyte and explores the the effects of TNF-αon the phagocytic function of macrophage and the phagocytosis of LDL and ox-LDL through a cytological study,which randomly classifies the cells into 2 groups,with the addition of TNF-αto group 1 and none to group 2.And the phagocytosis of macrophage is judged according to the LDL and ox-LDL Concentration measured by Enzyme-linked Immunosorbent Assay(ELISA).Results 1.lipids level:1.1 TC The apparent difference are found between the 3 groups(p＜0.01), among which the level of Group AMI is the lowest and the Group SAP is the highest.1.2 TG The apparent difference are found between the 3 groups(p＜0.01), among which the level of Group AMI is the lowest and the Group UAP is the highest.1.3 HDL-C No statically significent difference is found between Group SAP and Group UAP(p＞0.05);however significent differences are respectively measured between Group AMI and Group SAP and between Group AMI and Group UAP (p＜0.01);the level of Group AMI is the lowest and the level of Group SAP is the highest.1.4 LDL-C No statically significent difference is found between Group AMI and Group UAP(p＞0.05);however significent differences are respectively measured between Group SAP and Group AMI and between Group SAP and Group UAP (p＜0.01);the level of Group SAP is the highest and the level of Group AMI is the lowest.1.5 VLDL-C The apparent difference are found among the 3 groups(p＜0.05), among which the level of Group AMI is the lowest and the Group SAP is the highest.2.White Blood Cell(WBC) The difference between Unstable Angina Pectoris (Group UAP) and Stable Angina Pectoris(Group SAP) is not statistically significant (p＞0.05 ).The difference between Acute Myocardial Infarction(Group AMI) and Unstable Angina Pectoris(Group UAP) is statistically significant(p＜0.01),the level of Group AMI is the highest and the level of Group SAP is the lowest.3.LDL level of Group 1 with the addition of TNF-αis 12.25±0.50mg/dl while the level of Group 2 without addition of TNF-αis 23.25±2.06mg/dl(p=0.000047).It suggests the phagocytic function of macrophage and the phagocytosis of LDL,and the function is obviously strengthened if driven by the inflammatory factors; meanwhile,ox-LDL level of Group 1 with the addition of TNF-αis 69.34±6.68mg/dl, which is higher than that of Group 2 without addition of TNF-αis 23.25±2.06mg/dl (p=0.000047);and it suggests that apart from the phagocytosis of LDL,macrophage is also respensible for transforming a part of LDL into ox-LDL.4.Cytological study indicates that ox-LDL concentration inside the cell of Group 1 with the addition of TNF-αis higher than that of Group 2 without addition of TNF-α(p=0.012).Meanwhile,ox-LDL concentration outside the cell of Group 1 with the addition of TNF-αis lower than that of Group 2 without addition of TNF-α(p=0.0014).It suggests the phagocytic function of macrophage and the phagocytosis of ox-LDL,and the function is obviously strengthened if driven by the inflammatory factors.Conclusions 1.The levels of TC,LDL-C is lowest in Group AMI,the level is the highest in Group SAP,and the level in Group UAP is in between.Meanwhile,the declined level of TC,LDL-C,is observed along with the increased instability of atherosclerotic lesions.2.Group AMI The levels of TC,LDL-C,TG are all within the normal range:TC (4.808±1.008 mmol/L),TG(1.430±0.990 mmol/L) and LDL-C(3.269±2.302 mmol/L).On the other hand,the levels of TC and LDL-C in Group SAP and Group UAP are all beyond the normal range,which suggests that apart from the factor of dyslipidemia,other factor also leed to unstable atherosclerotic lesion;inflammation response also plays a remarkable role in the formation and development of atherosclerosis and has an effect on lipids level.3.The proportions of white blood cell and neutrophils in Group AMI are both higher than that in Group SAP and Group UAP,and the proportion of neutrophils is obove the normal range,which suggests the existence of acute inflammation response after the onset of AMI.4.Normally,1/3 LDL is eliminated by the macrophage within the net-shaped endothelial cell system and the macrophage functions properly in the phagocytosis of LDL and ox-LDL.Meanwhile,its ohagocytosis is evidently enhanced after the activation by inflammatory response factors and the macrophage in the mononuclear phagocyte system eliminated wore LDL.5.It's possible that the normal or declined lipids level(TC,TG,LDL-C) during the onset of Acute Myocardial Infarction has much to do with the remarkable enhancement of macrophage's activation and the phagocytosis of LDL and ox-LDL which is due to inflammation response after the onset of AMI.6.It can be deducted that the inflammation factor can cause the activation of macrophage within the atherosclerotic lesion and its phagocytosis of lipoprotein as well as the formation of ox-LDL,which will rapidly increase the number of foam cells in the lesion,the breaking of unstable lesion and the onset of AMI in the end. Therefore,the anti-inflammation response is crucial not only to the treatment of AMI in early stage,but also to the prevention of it in the process of atherosclerosis therapy.7.This dissertation also notes acute inflammation response as one of the possible reasons for the declined LDL-C level with AMI patients;besides,the standard for Regulating blood lipid therapy needs further decline and the specific standard still needs further researches.
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