冠状动脉粥样硬化性心脏病患者凝血酶激活的纤溶抑制物及其编码区基因多态性的研究

目的 探讨凝血酶激活的纤溶抑制物(thrombin aetiralable fibrinolysis inhibitor,TAFI)及其编码基因CPB2单核苷酸多态性与冠状动脉粥样硬化性心脏病(冠心病)之间的联系.方法 应用聚合酶链反应-限制性片段长度多态性分析技术(polymerase chain reaction-restriction fragment length polymorphism,PCR-RFLP)检测210例冠心病患者和190名正常对照者的TAFI基因编码区Thr325Ile、Tnr147Ala多态性分布特点,同时应用发色底物法和ELISA法分别测定TAFI的活性及抗原,并进一步分析基因多态性与TAFI的活性及抗原之间的关系.结果 冠心病组(心肌梗死组及心绞痛组)血浆中TAFI的活性及抗原水平均较对照组显著增高,差异有统计学意义.CPB2基因C1040T(Thr325Ile)及G505A(Thr147Ala)2个位点的3种基因型在冠心病组和对照组的频率分布分别为C1040C(Thr325Thr)67(31.9%)、64(33.6%);C1040T(Thr325Ile)109(51.9%)、92(48.4%);T1040T(Ile325Ile)34(16.2%)、34(17.8%);G505G(Ala147 Ala)75(35.7%)、72(37.8%);G505A(Thr147Ala)112(53.3%)、96(50.5%);A505A(Thr147Thr)23(10.9%)、22(11.7%),经x2检验,基因型分布符合Hardy-Weinberg平衡,并且两组之间各种基因型频率分布差异无统计学意义(P>0.05).在冠心病组和对照组Thr325Ile不同的基因型对TAFI活性没有影响;对TAFI抗原含量的影响则以Thr325Thr纯合基因型者血浆TAFI抗原浓度最高,较其他两型差异有统计学意义(P<0.05),Thr325Ile与TIle325Ile型之间则差异无统计学意义(P>0.05).而Tnr147Ala基因多态性与血浆中TAFI活性及抗原水平之间的差异均无统计学意义(P>0.05).结论 TAFI具有抑制纤溶的作用,可能是冠心病发病的危险因子.TAFI编码区基因Thr325Ile的多态性对血浆中TAFI抗原水平有明显影响,但Thr325Ile、Thr147Ala的多态性与冠心病的发生没有明显的相关性.

Study on the association of thrombin activatable fibrinolysis inhibitor and the Thr325Ile and Thr147Ala polymor-phisms of its encoding gene CPB2 in patients with coronary heart disease

OBJECTIVE: To investigate the association of thrombin activatable fibrinolysis inhibitor (TAFI) and its encoding gene CPB2 polymorphism in patients with coronary heart disease (CHD). METHODS: The CPB2 gene polymorphisms of Thr325Ile and Thr147Ala were analyzed with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in patients of acute myocardial infarction (n=100), acute angina pectoris (n=110) and a control group (n=190). The antigen (Ag) and activity (Act) of the TAFI were determined by sandwich enzyme link immunosorbent assay specific for human TAFI and chromogenic assay for activated human TAFI in plasma, respectively. The relationship between Thr325Ile and Thr147Ala gene polymorphism and TAFI Ag and Act were also analyzed. RESULTS: Plasma TAFI Act and TAFI Ag in acute myocardial infarction group and acute angina pectoris group (CHD patients group) were both significantly higher than those of the control group. The genotype frequencies of Thr325Ile (C1040T) and Thr147Ala (G505A) were as the following: C1040C (Thr325Thr) 67 (31.9%) and 64 (33.6%); C1040T (Thr325Ile) 109 (51.9%) and 92 (48.4%); T1040T (Ile325Ile) 34 (16.2%) and 34(17.8%); G505G (Ala147 Ala) 75 (35.7%) and 72 (37.8%); G505A(Thr147Ala) 112 (53.3%) and 96 (50.5%); A505A(Thr147Thr)23 (10.9%) and 22 (11.7%), in the CHD patients and control respectively. Chi-square analysis showed no significant difference in the Thr325Ile and Thr147Ala polymorphism distributions (P > 0.05). In addition, at the 325 position, the TAFI antigen of the Thr325Thr was higher than that of the other genotypes (Thr325Ile and Ile325Ile, P < 0.05). There was no statistical significance between the TAFI antigen of the Thr325Ile and Ile325Ile (P > 0.05). No significant correlation was found between the TAFI Act and the Thr325Ile polymorphism. At the position 147, significant correlation between the polymorphism of the Thr147Ala and TAFI Ag and Act was not found. CONCLUSION: TAFI plays an important role in anti-fibrinolysis. It might be a risk factor for acute myocardial infarction and acute angina pectoris. The Thr325Ile polymorphism had obvious effect on TAFI antigen levels, but the Thr325Ile and Thr147Ala polymorphism had no association with coronary heart disease.