Relationship between gene polymorphism of the PAI-1 promoter and myocardial infarction

To investigate the association between gene polymorphism of the plasminogen activator inhibitor-1 (PAI-1) and myocardial infarction (MI) in Chinese. PAI-1 genotyping with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific polymerase chain reaction (ASPCR) was performed in 87 myocardial infarction patients and 92 unrelated healthy controls. All subjects' clinical features and PAI-1 activity were tested. There were two polymorphisms within the promoter, a G/A single base substitution polymorphism upstream at -844 bp, and a single guanosine deletion/insertion 4G/5G polymorphism -675 bp upstream from the start of transcription. Significant differences between the patients and the controls were observed neither for the frequencies of the GG, GA and AA genotypes nor for the PAI-1 activities of these three types. But for the 4G/5G polymorphism, there were significant differences between patients and controls for the frequencies of the 4G/4G, 4G/5G and 5G/5G genotypes (P < 0.05). In the MI group, the PAI-1 activity of the 4G/4G type was significantly higher than that of the 5G/5G type (P < 0.05). Further more, a positive correlation between the glucose level and PAI-1 activity was found (r = 0.34, P = 0.02). This study indicates that the 4G/5G gene polymorphism of PAI-1 is associated with myocardial infarction, that 4G/4G type is probably an important hereditary risk factor, and that glucose has functional importance in regulating PAI-1 activity.