The Correlation Of Lipoprotein(a) With Coronary Artery Disease And The Effects On The Fibrinolysis

Background and object: Hyperlipidaemia is one of the major contributors to atherosclerosis and Coronary Heart Disease (CHD) in our society. Numerous clinical and epidemiological studies have shown repeatedly that an elevated blood Lipoprotein(a) level is one of the major modifiable risk factors associated with the development of CHD. To date, the mechanisms of the Lp(a) effect on the CHD were summarized on two aspects: (1) Lipoprotein(a) is a structurally and functionally unique lipoprotein consisting of the glycoprotein apolipoprotein(a) covalently linked to LDL, which assemble the LDL receptor on endothelial cells leading to deposition of cholesterol in intima. (2) The structural of apolipoprotein(a) is similarity to plasminogen(Plg) and its functional studies in vitro have identified the serine sites were substituted by arginine which mediate its inhibitory effects on fibrin clot lysis, binding to fibrin and other biological substrates, and pro-inflammatory and anti-angiogenic properties through to compete assemble flg recepertor, inhibit t-PA production and stimulate PAI-I expression. However, elevated concentration of plasma lipoprotein(a) is a risk factor for a variety of vascular diseases, including coronary heart disease, ischemic stroke and venous thrombosis. Whereas many pathogenic mechanisms have been proposed for lipoprotein(a) remain no clearly. We investigated the amount of Lp(a),Plg, t-PA, PAI-I and FIB in plasma in CHD patients with the coronary angiographic findingscontrast to the normal, to explore the correlation of Lp(a) with CHD and fibrinolysisMethods: The 252 patients in hospital due to chest pain were obtained with coronary angiographic examination from the 2003.1 to 2003.12. According to the angiographic findings, all patients were divided three groups: normal group(the lumen of coronary artery was occluded<49%), angioplasty group(the lumen of coronary artery was occluded 50-90%) and occluded group(the lumen of coronary artery was occluded >90%). According to their number of injured vessels, we also divided them into three groups: normal group, one branch group and multiple branchs group. The blood samples with patients were collected in the morning, treated with EDTA, then gathered the plasma and stored in 4 degree. The concentrations of Lp(a),Plg, t-PA,and PAI-I in all patients were measured by ELISA assay. The concentration of FIB was measured by coagulation method. All data were analysis with SPSS 11.0 software.Results:(l) The serum Lipoprotein(a) concentrations have a significant increase in the multiple branchs group compare to one branch group(p<0.01). (2) Lipoprotein(a) concentration increase with the severity of coronary artery lesions. The amount of Lipoprotein(a) in occluded group was higher obversiouly than that in normal group(p<0.01). (3) As an independent risk factor, the level of Lipoprotein(a) expression in plasma bears no relationship to other lipoproteins(p>0.05). There were positive associations between Lp(a) and t-PA, Plg and PAI-I but FIB(p<0.01).Conclusions: (1) Neither the metabolism product from other lipoproteins nor transformation other lipoproteins, Lipoprotein(a) is an independent lipoprotein, which plays an important role in the forming and disruption of plague in coronary artery. (2) Lipoprotein(a) interferes with the physiological function of Plg, inhibits t-PA secretion, prompts PAI-I expression, disturbs the dynamic equilibrium between coagulation and fibrinolysis and leads to growth...