【摘要】 目的探讨同型半胱氨酸(homocysteine,Hcy)对血管内皮细胞纤溶系统影响。方法(1)将体外培养的人脐静脉血管内皮细胞(HUVEC)分为10个实验组(0、10、50、200、500μmol/LHcy组及叶酸和上述各Hcy点共同培养组),培养24h后,酶联免疫吸附实验法(ELISA)测定各组细胞上清液中纤溶酶原激活剂(plasminogenactivator,tPA)及纤溶酶原激活物抑制剂1(plasminogenactivatorinhibitor1,PAI1)抗原含量,逆转录聚合酶链反应分析(RTPCR)法分析各组tPA及PAI1的mRNA表达水平。(2)急性心肌梗死(AMI)患者53例及健康对照组48例,ELISA测定空腹血浆tPA及PAI1含量,高效液相色谱法测定血浆Hcy水平。结果(1)500μmol/LHcy组PAI1抗原及mRNA表达水平均明显增高(P<0.05)。(2)以单纯培养基为对照组,生理浓度Hcy组内皮细胞tPA抗原合成及mRNA表达明显增高(P<0.05),而以10μmol/LHcy组为对照组时,500μmol/LHcy组tPA抗原合成及mRNA表达水平则明显减少(P<0.05)。(3)500μmol/LHcy与叶酸共同培养组和单纯Hcy组相比,可以明显提高内皮细胞tPA抗原的合成及mRNA表达,减少PAI1抗原合成及mRNA表达(P<0.05)。(4)AMI组Hcy、tPA及PAI1均明显高于健康对照组(P<0.05)。结论在体外细胞时,超生理浓度Hcy可以通过下调tPA、上调PAI1的mRNA表达,减少内皮细胞tPA抗原的分泌及增加PAI1抗原的合成,可能降低纤溶系统的活性。叶酸则可以减少Hcy引起内皮细胞纤溶系统的损害,起到保护作用。Hcy是AMI的一个独立危险因素。更多还原

【Abstract】 Objectives To investigate the relationship between homocysteine (Hcy) and the fibrinolytic system in acute myocardial infarction (AMI) and human umbilical vein endothelial cells (HUVEC).Methods Cultured HUVEC was divided into 10 groups (0, 10, 50, 200, 500 μmol/L Hcy with or without 15 μmol/L of folic acid). There were 53 patients of acute myocardial infarction(AMI) and 48 healthy controls. The plasminogen activator inhibitor-1 (PAI-1) and activator of plasminogen (tPA) antigen levels in HUVEC′s supernatant and plasma were measured with Elisa kit. Concentration of plasma Hcy was measured by reverse-phase high-performance liquid chromatography with recolumn derivatization and fluorometric detection in the patients and healthy controls. Total RNA was extracted using the guanidinium isothiocyanate method. The semi-quantification of PAI-1 and tPA mRNA in HUVEC was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR). Results (1)PAI-1 mRNA and secreted protein levels were both significantly enhanced by Hcy at the concentration of 500 μmol/L, compared with the control group (P<0.05). (2) The tPA mRNA and antigen levels were decreased significantly at concentration of 500 μmol/L of Hcy, compared with that of 10 μmol/L Hcy (P<0.05), but compared with the control group(0 μmol/L), the tPA mRNA and antigen levels of 10 μmol/L of Hcy were much higher (P<0.05 ). (3) The addition of folic acid reduced PAI-1 but increased tPA at both mRNA and protein levels, which were both obvious at concentrations of 500 μmol/L Hcy, compared with only Hcy group (P<0.05).(4) Hcy, tPA, and PAI-1 antigen levels were increased in AMI group. Hcy is a independent risk factor of AMI (P<0.05). There weren′t significant correlation between Hcy and tPA or Hcy and PAI-1 in both groups(P>0.05), although the coefficient correlation was higher in patients than in controls.Conclusions These results suggested that hyperhomo-cysteinemia increased the incidence of thrombotic disease, which may be caused by decreasing the activity of fibrinolytic system, whereas, folic acid may be protective against the toxic action of Hcy.更多还原