Tissue factor A-603G genotype associates with carotid intima-media thickness in subjects undergoing cardiovascular risk prevention

Tissue factor (TF), key initiator of coagulation, is also ascribed a non-haemostatic function in inflammation, cell migration and proliferation, suggesting a role of TF not only in thrombosis but also in atherosclerosis development. Polymorphisms in the TF gene promoter have been shown to modulate the expression of TF, and thereby potentially also its involvement in atherosclerosis and individual predisposition to atherosclerotic disease. Hence, this study was aimed at investigating associations between TF promoter polymorphisms and carotid intima-media thickness (IMT), a well-established surrogate marker of atherosclerotic disease. To this end, the TF A-603G polymorphism was analyzed in 316 subjects enrolled in a primary and secondary cardiovascular risk prevention programme, with measurements of carotid IMT by B-mode ultrasound. Also, the TF Ins-1208Del polymorphism was investigated in a limited number of subjects, which confirmed the previously reported complete concordance between the -603A and -1208Del alleles. The subjects were aged 60.2±8.4 years, 80% were male, and 78% were undergoing secondary prevention with a history of coronary, cerebrovascular, or peripheral atherosclerotic disease. Both mean and maximum carotid IMT (measured at the common carotid artery, carotid bifurcation, and internal carotid artery) differed significantly according to A-603G genotype, being highest in -603N A (n=93), intermediate in NG (n=161) and lowest in G/G (n=62) (mean IMT: A/A 1.31±0.36 mm, NG 1.27±0.33 mm, G/G 1.19±0.32 mm; max IMT: A/A 2.36±0.88 mm, NG 2.26±0.85 mm, 2.05±0.88 mm; both p<0.05; adjusted for age, gender, and statin treatment). In summary, a significant association between TF promoter genotype and carotid IMT was observed, perhaps mediated via alterations of TF expression levels in the circulation or within the carotid vessel wall. These findings support the hypothesis that TF plays a role in the atherosclerotic process, beyond its well-known role in haemostasis and thrombosis, thus further implicating TF not only in thrombotic complications of atherosclerotic disease, but also in plaque progression.