Background: 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.
Methods: 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.
Results: 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).
Conclusions: 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.