Association Of Plasminogion Activator Inhibitor-1 Gene 4G/5G Polymorphism And Activity In Plasma With Repeated Spontaneous Abortion

Objective To investigate the relationship of the polymorphism in plasminogion activator inhibitor-1 gene and PAI-1 activity levels in plasma with repeated spontaneous abortion in Chinese women of Han nationality.Methods The 4G/5G polymorphism of PAI-1 gene in 60 repeated spontaneous abortion patients (study group) and 51 healthy non-pregnant women (control group Ⅰ ) and 54 normal pregnant women (control group Ⅱ ) was detected by reaction-restriction fragment length polymerase chain polymorphism (PCR-RFLP); The plasma PAI-1 activity was detected by synthetic chromogenic substrate assay, x~2 analyses were used to compare Genotypic frequencies and allele frequencies between women with and without thrombophilic gene mutation,and odds ratio(OR)was aquired to assess the relative risk of thrombophilia in the same way. One way ANOVA was used to compare PAI-1 activity between genotypes and groups. Results The genotype frequencies of plasminogion activator inhibitor-1 gene in study group was 38.3% for 4G/4G, 48.4% for 4G/5G and 13.3% for 5G/5G. There were significant differences between study group and control group about the genotype frequencies. And the 4G/4G genotype and 4G allele frequencies (38.3%and62.5%) in spontaneous abortion patients were higher than those (15.7% and 45.1%) in control group I and those (16.7%and 47.2%) in control group Ⅱ (P<0.05).The PAI-1 4G/4Ggenotype was significantly associated with spontaneous abortion (OR=3.341,95% confidence interval CI: 1.336-8.857,vs control group). Samely, the 4G allele was associated with spontaneous abortion (OR=2.209,95% CI: 1.186-3.472,vs control group). The plasma PAI-1 activity was 0.826±0.068( AU/ml) for 4G/4Q0.713 + 0.041 ( AU/ml) for 4G/5G and 0.691 ±0.038 ( AU/ml)for 5G/5G. The plasma PAI-1 activity in 4G allele homozygous genotype was higher than those in 4G/5G heterozygous and 5G allele homozygous, there were significant differences between every two genotypes(P=0.000~ 0.041), The plasma PAI-1 activity in 4G/4G genotype was approximately 19.5% higher than that in 5G/5G genotype. The plasma PAI-1 activity in spontaneous abortion patients group was 12.02% higher than that in the control group I .Conclusion The PAI-1 gene polymorphism is present in Chinese women of Han nationality and keep close correlation with unexplained repeated spontaneous abortion patient; The plasminogen activator inhibitor-1 (PAI-1) gene-675 4G/5G variations might represent risk factor for repeated spontaneous abortion, in which the PAI-1 4G homozygous genotype and 4G allele frequencies was significantly associated with repeated spontaneous abortion; The plasma PAI-1 activity that increases significantly after pregnancy may be one of the independent risk factors contributing to poor pregnancy outcomes; Detection and discover of thrombophilic mutations by molecular biological methods may be helpful to clinical diagnosis and estimation of pregnancy outcomes, prophylactic anticoagulant therapy may improve pregnancy outcomes to a certain degree.