Influence of renin-angiotensin system gene polymorphisms on the risk of ST-segment-elevation myocardial infarction and association with coronary artery disease risk factors.

BACKGROUND: Recent advances in molecular biology have made it possible to identify numerous polymorphisms of the renin-angiotensin system, which play an important role in the etiology of cardiovascular disease.
OBJECTIVE: The aims of the study were (i) to assess the distribution of the angiotensin II type 1 receptor (AGTR1) gene 1166A/C polymorphism and two polymorphisms of the angiotensinogen (AGT) gene (Met235Thr and Thr174Met) in patients with ST-segment-elevation myocardial infarction (STEMI) who underwent coronary angiography, compared with healthy volunteers; (ii) to determine if there was any correlation between these polymorphisms and risk of STEMI; and (iii) to assess the association of the examined polymorphisms with such classic cardiovascular risk factors as hypertension, diabetes mellitus, obesity (based on a body mass index ≥25 kg/m2), smoking, dyslipidemia, and family history of cardiovascular disease.
METHODS: A total of 100 patients (mean age 57 ± 10 years [range 31-76 years]; 21% women) with diagnosed STEMI and a control group consisting of 95 healthy volunteers (mean age 38 ± 11 years [range 17-60 years]; 20% women) were investigated for the AGTR1 1166A/C polymorphism and two variants of AGT (Met235Thr and Thr174Met). All patients received standard therapy for STEMI.
RESULTS: There were significant differences in the distribution of genotypes and the AGT Met174 allele for AGT Thr174Met polymorphism between patients and healthy subjects (p < 0.05). The AGTR1 1166A/C polymorphism genotype frequencies were significantly different in patients with hypertension compared with normotensive individuals. Specifically, the AGTR1 1166 AA genotype was twice as common in patients with hypertension as in those without (67% vs 33%), while the AC and CC genotypes were found predominantly in normotensive patients (p = 0.0016). The variant 1166C allele was much more common in patients without hypertension (67%) than in patients with hypertension (33%; p = 0.0006). The variant AGT Thr235 allele was more common in patients without a family history of cardiovascular disease than in patients with this risk factor (p < 0.05). The odds ratio (OR) for STEMI in patients with the heterozygous AGT 174 Thr/Met genotype was increased to 1.884 (95% confidence interval [CI] 1.03, 3.446; p < 0.05), while the OR calculated for carriers of the AGT Met174 allele was 2.038 (95% CI 1.129, 3.68; p = 0.0182). Significant genotypic associations of combinations of renin-angiotensin system gene polymorphisms in STEMI were not observed.
CONCLUSIONS: The most powerful predictive value for STEMI was represented by the Thr/Met genotype and the Met174 allele of the AGT Thr174Met gene polymorphism. In our study, in contrast to observations reported by other authors, the AA genotype of the AGTR1 1166A/C gene polymorphism - much more than other genotypes - was associated with hypertension.