Interaction between MMP-9 gene polymorphisms and smoking in relation to myocardial infarction in a Uighur population

Matrix metalloproteinase 9 (MMP-9) plays a pivotal role in early atherosclerosis, vascular remodeling, and development of arterial plaque rupture. The potentially functional MMP-9 gene polymorphism may contribute to the susceptibility of myocardial infarction (MI). We aimed to investigate the association between the interaction of 2 single-nucleotide polymorphisms ([SNPs] -1562C>T and R279Q) of the MMP-9 gene and smoking with MI in a Uighur population of China.

A case-control study composed of 384 coronary angiography proven patients with MI and 451 sex-matched and ethnically matched control participants were enrolled in the study. The genotypes of the 2 selected SNPs were determined by the method of polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

Analysis of 2 SNPs, the frequency of -1562 CT and TT genotypes in MI group was significantly higher than in control group (25.52% vs 17.29%; P = .004). And the -1562 T allele showed significant association with MI (MI vs controls: 14.19% vs 9.31%; P = .002). R279Q locus did not show significant differences between patients and controls ( P > .05). Multiple logistic regression analysis showed that -1562 T allele (CT or TT genotype; odds ratio [OR] 1.31, 95% confidence interval [CI] 1.22-1.40; P = .004), the interaction between -1562 T allele and smoking (OR 4.42, 95% CI 2.74-7.13; P < .001), and the interaction between 279 Q allele and smoking (OR 2.07, 95% CI: 1.04-4.13; P = .021) were independent risk factors for MI.

There findings suggest that MMP-9 -1562C>T polymorphism could be associated with the susceptibility to MI. Another SNP (R279Q) polymorphism was not significantly associated with MI. The -1562C>T or R279Q polymorphism of MMP-9 gene and smoking have a synergistic effect and are significantly associated with the risk of MI in Chinese Uighur population, respectively.