Left ventricular mass, carotid wall thickness, and angiotensinogen gene polymorphism in patients with hypertension

A missense gene mutation with methione-to-threonine amino acid substitution at codon 235 (M235T) of angiotensinogen (AGT) has been associated with higher plasma AGT levels and may influence the pathogenesis of cardiac hypertrophy and atherosclerosis. This study was undertaken to investigate the relationship of the M235T polymorphism of the AGT gene with left ventricular mass (LVM) and carotid intima-media thickness (IMT) in 175 Chinese patients with hypertension. The M235T mutation was detected by a mispairing primer method to create a BstUI restriction site in the polymerase chain reaction. The LVM was calculated with M-mode echocardiographic measures of the left ventricle. The IMT was measured in the common carotid and carotid bifurcation by B-mode ultrasound. Patients with the TT genotype (n = 106) were found to have significantly greater LVM index than those with the MM (n = 32) and MT (n = 37) genotypes (129.2 +/- 34.3 v 112.5 +/- 38.3 and 107.4 +/- 30.0 g/m2, P = .002), but the carotid IMT showed insignificant differences among three genotypic groups (1.320 +/- 0.703, 1.349 +/- 0.777, and 1.309 +/- 0.797 mm, P = .97). The M235T polymorphism (P = .004) was a significant predictor for LVM on multiple regression analysis, controlling all the potential confounding factors including age (P = .04), gender (P = .000), body mass index (P = .000), and so on, but the carotid IMT correlated only with age (P = .000), smoking (P = .02), and tissue plasminogen activator antigen (P = .02). These results indicated that the TT genotype of the AGT gene could be considered a risk factor for the development of cardiac hypertrophy, but not for carotid atherosclerosis in the hypertensive population.