Plasma concentration, genetic variation, and gene expression levels of matrix metalloproteinase 9 in Iranian patients with coronary artery disease

Background: Matrix metalloproteinase 9 (MMP9) -1562C> T (rs3918242) polymorphism has been proposed as a risk factor for coronary artery disease (CAD) with conflicting results. The aim of the present study was to investigate the association of -1562C> T genetic polymorphism, gene expression and circulating levels of MMP9 with CAD risk in an Iranian subpopulation in in Zanjan City. Materials and Methods: This was a retrospective case-control study we investigated retrospectively 100 patients with angiographically verified CAD and 100 matched controls. Genotyping of -1562C> T polymorphism was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Gene expression levels and circulating levels of MMP9 was determined by real-time reverse transcription-PCR and enzyme immunoassay method, respectively. Statistical analysis was done using Student's t-test or Chi-square test by SPSS 16 software. Results: The mean circulating levels of MMP9 were significantly higher in CAD Group than control group (P= 0.002). Mean plasma levels of MMP9 were also significantly higher in triple vessel stenosis patients than double vessel or single vessel stenosis patients (P< 0.001). Moreover, mean plasma levels and gene expression levels of MMP9 were significantly higher in T allele carrier than C allele carrier of MMP9 -1562C> T polymorphism (P= 0.002, P= 0.01, respectively). However, genotype and allele frequencies of MMP9 -1562C> T polymorphism were similar between CAD patients and controls (P> 0.05). Additionally, the -1562C> T polymorphism of MMP9 gene didn't increase the risk of CAD in dominant (P= 0.537) or recessive(P= 0.249) genetic models. Conclusion: Our study demonstrated that circulating levels of MMP9 but not -1562C> T polymorphism of MMP9 gene may be a risk factor for development and severity of CAD in an Iranian subpopulation in Zanjan.