Association of the MMP7 –181A>G promoter polymorphism with early onset of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by decreased air flow and is associated with abnormal chronic inflammation in the airways and extensive tissue remodeling. Matrix metalloproteinase-7 (MMP7) is produced primarily by the epithelium of many organs, including the lungs. A functional MMP7 –181A>G (rs11568818) promoter polymorphism influences the binding of nuclear regulatory proteins modulating the transcription of the gene. In this study, we genotyped 191 patients with COPD for MMP7 –181A>G single nucleotide polymorphism (SNP) and 215 control subjects using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and explored the role of that polymorphism as a risk factor for COPD. There were no differences in the genotype and allele distribution of the MMP7 –181A>G SNP between the COPD patients and control groups (p = 0.341 and p = 0.214). However, the carries of the G allele (AG and GG genotypes), appeared to develop COPD significantly earlier than those with the AA genotype (61.01 ± 10.11 vs. 64.87 ± 9.00 years, p = 0.032). When the genotype distribution was studied only in the groups of patients (n = 76) and controls (n = 106) younger than 60 years, we found significantly higher frequency of the carriers of the G allele in COPD patients than in the controls, determining about a 3-fold higher risk for COPD [odds ratio (OR) –3.33, 1.36-8.14, p = 0.008 for GG, and OR = 2.91, 1.38-6.13, p = 0.005 for AG+GG]. Based on our results, the MMP7 –181A>G promoter variant may influence early development of COPD. This effect could be attributed to the increased production of the enzyme resulting in enhanced airway wall protein degradation and injury.