Genotype frequency of plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism in healthy Japanese males and its relation to PAI-1 levels

Plasminogen activator inhibitor-1 (PAI-1) plays an inhibitory role in the f ibrinolytic enzyme system and is associated with thrombotic diseases. The g ene for PAI-1 has an insertion/deletion polymorphism at the promoter region , the 4G/5G polymorphism, which is related to differences in transcription activity in vitro. Association of the 4G/5G polymorphism with plasma PAI-1 levels, however, has not been uniformly reported. We evaluated the relation ship between the 4G/5G polymorphism and plasma PAI-1 antigen levels in 104 Japanese males not taking lipid-lowering drugs and without non-insulin-depe ndent (type 2) diabetes mellitus or coronary artery disease. The genotype f requency was 37.5%, 50.0%,and 12.5% for 4G/4G, 4G/5G, and 5G/5G genotypes, respectively, which differs from that reported for healthy Caucasian males (P < 0.01), with the 4G allele more frequently found in the Japanese popula tion. No association was found between the 4G/5G polymorphism and plasma PA I-1 antigen levels. Multiple regression analysis revealed a significant (P < 0.01) contribution of triglyceride (TG) levels to variations in plasma PA I-1 antigen levels. The correlation between TG levels and plasma PAI-1 anti gen levels was not 4G/5G genotype-specific. These findings suggest that PAI -1 4G/5G polymorphism is not associated with plasma PAI-1 antigen levels am ong healthy Japanese males and that TG levels correlate to plasma PAI-I ant igen levels in all PAI-1 4G/5G genotypes. (C) 1999 The Japanese Society of Hematology.