Genetic polymorphism of matrix metalloproteinase (MMP)-9 does not affect plasma MMP-9 activity in healthy subjects

Plasma MMP-9 levels have been shown to predict cardiovascular risk, and a functional substitution C to T at position − 1562 in the promoter region of the MMP-9 gene has been associated with the severity of cardiovascular diseases. We examined the association between the C − 1562 T polymorphism and MMP-9 activity in healthy subjects. We studied 200 healthy male white volunteers (age range: 20–55 y) who were nonsmokers and were not taking medicines. Genomic DNA was extracted and genotypes for the C − 1562 T polymorphism were determined by PCR and restriction fragment length digestion. Plasma was assayed for pro-MMP-9 and MMP-9 activities by gelatin zymography. The frequency of the alleles “C” and “T” were 90% and 10%, respectively. Because of the relatively low frequency of the TT genotype, we combined both TT and CT genotypes together (CT + TT group) and compared with the CC genotype group. We found no differences in pro-MM9 and MMP-9 activity levels among the genotype groups (both P > 0.05). While the present study indicates lack of effect for the C − 1562 T polymorphism on MMP-9 activity in plasma, it is possible that the C − 1562 T polymorphism contributes to an increased cardiovascular risk under conditions of induced MMP-9 expression.