MMP-3 (-1171 5A/6A; Lys45Glu) variants affect serum levels of matrix metalloproteinase (MMP)-3 and correlate with severity of COPD: A study of MMP-3, MMP-7 and MMP-12 in a Tunisian population.

Background: The present study aimed to examine the role of matrix metalloproteinase (MMP)-3 [(-1171) 5A/6A; Lys45Glu (A/G)], MMP-7 [(-181) A/G] and MMP-12 [(-82) A/G; Asn357Ser (A/G)] variants in the development and severity of chronic obstructive pulmonary disease (COPD) in Tunisians.

Methods: Plethysmography was performed in all participants to measure forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC parameters. Genotyping of MMP-3, MMP-7 and MMP-12 polymorphisms was carried out in 138 patients with COPD and 216 healthy controls using a polymerase chain reaction-restriction fragment length polymorphism. Serum levels of MMPs and cytokines (interleukin-6, tumor necrosis factor-α) were determined by an enzyme-linked immunosorbent assay.

Results: No significant correlations were observed between genetic variations in MMP-3, MMP-7 and MMP-12 and the risk of development of COPD. Additionally, no impact of MMP-7 (-181) A/G and MMP-12 [(-82) A/G; Asn357Ser (A/G)] polymorphisms was observed on the respective protein levels and clinical parameters of the disease. Interestingly, both MMP-3 (-1171) 5A/6A and Lys45Glu (A/G) variants were associated with respiratory function, as well as with serum levels of MMP-3 in COPD patients. A relationship was found between the (-1171) 6A and 45Glu (G) alleles of the MMP-3 gene and enhanced airflow limitation among COPD patients. Additionally, carriers of the 6A6A and 45 GG genotypes present higher MMP-3 levels than noncarriers.

Conclusions: MMP-3 (-1171) 5A/6A and Lys45Glu (A/G) polymorphisms were associated with the decline of lung function among COPD patients. These results could be linked to the upregulation of MMP-3 in serum from COPD patients carrying the (-1171) 6A and 45 G homozygous genotypes.