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.