Background: Matrix metalloproteinase-9 (MMP-9) is involved in the degradation of the extracellular matrix during physiological and pathological processes. Two functional polymorphisms [C(-1562)T and microsatellite (CA)13-25] in the promoter region of the MMP-9 gene have been associated with several diseases. The aim of this study was to examine whether these MMP-9 polymorphisms and haplotypes are linked with plasma MMP-9 variations in healthy subjects.
Methods: We studied 177 healthy male white volunteers (age range 20-55 years) who were non-smokers and not taking any medication. Genomic DNA was extracted from whole blood and genotypes for the C(-1562)T and the microsatellite (CA)n polymorphisms were determined. MMP-9 levels were measured in plasma samples by gelatin zymography.
Results: The frequency of the alleles C and T for the C(-1562)T polymorphism were 90% and 10%, respectively. The frequency of the alleles with less than 21 CA repeats (L) and with 21 repeats or higher (H) were 47% and 53%, respectively. We found no differences in plasma MMP-9 levels among the genotype groups or among different haplotypes (all p>0.05).
Conclusions: These findings suggest that functional polymorphisms in the promoter of the MMP-9 gene are not linked with significant plasma MMP-9 variations in healthy subjects.