Background and purpose: The matrix metalloproteinases (MMPs) are a family of enzymes that are important in the resorption of extracellular matrix and are involved in atherogenesis. Recently, 2 common polymorphisms on MMP-1 (1G/2G) and MMP-3 (5A/6A) gene promoters have been described. The aim of this study was to investigate a possible association between MMP polymorphisms and increased risk of internal carotid artery (ICA) stenosis.
Methods: We studied 91 patients consecutively recruited for ICA stenosis who had undergone carotid endarterectomy and 133 subjects without ICA stenosis (controls). Polymorphic genotypes were determined by polymerase chain reaction and sequencing analysis.
Results: The frequency of the 6A allele was significantly different between cases and controls: 0.62 and 0.50, respectively (odds ratio [OR], 1.58; 95% CI, 1.08 to 2.33; P=0.017). The frequency of 6A/6A genotype was significantly higher in cases with involvement of both carotids (OR, 3.13; 95% CI, 1.14 to 8.5; P=0.026) and in patients with stenosis >70% (OR, 2.55; 95% CI, 1.07 to 6.07; P=0.033). No significant differences were observed in MMP-1 distribution. Patients who were homozygous for both the 6A and 2G alleles had an elevated relative risk of ICA stenosis (OR, 2.66; 95% CI, 1.23 to 5.72; P=0.016). Multiple logistic regression analysis using the common risk factors and the 6A and 2G allele variants revealed that the 6A allele was an independent risk factor for ICA stenosis (P=0.049). When 6A/6A and 2G/2G were combined, the risk factor for ICA stenosis was 3-fold higher (OR, 3.31; 95% CI, 1.48 to 7.42; P=0.004).
Conclusions: Homozygosity for the 6A allele of the MMP-3 promoter is associated with carotid stenosis and, in association with MMP-1 2G homozygosity, predicts an increased risk of ICA stenosis. Even if obtained from a relatively limited patient series, these results might have relevant implications for treatment of ICA stenosis and possibly prevention of carotid-related stroke.