Open Access Research article

The C242T polymorphism of the p22-phox gene (CYBA) is associated with higher left ventricular mass in Brazilian hypertensive patients

Roberto Schreiber1, Maria C Ferreira-Sae1, Juliana A Ronchi2, José A Pio-Magalhães1, José A Cipolli1, José R Matos-Souza1, José G Mill3, Aníbal E Vercesi2, José E Krieger4, Kleber G Franchini1, Alexandre C Pereira4 and Wilson Nadruz Junior1*

Author Affiliations

1 Department of Internal Medicine, University of Campinas, Campinas, Brazil

2 Department of Clinical Pathology, University of Campinas, Campinas, Brazil

3 Federal University of Espírito Santo, Vitória, Brazil

4 Laboratory of Genetics and Molecular Cardiology, Heart Institute (InCor), University of São Paulo, São Paulo, Brazil

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BMC Medical Genetics 2011, 12:114  doi:10.1186/1471-2350-12-114

Published: 31 August 2011

Abstract

Background

Reactive oxygen species have been implicated in the physiopathogenesis of hypertensive end-organ damage. This study investigated the impact of the C242T polymorphism of the p22-phox gene (CYBA) on left ventricular structure in Brazilian hypertensive subjects.

Methods

We cross-sectionally evaluated 561 patients from 2 independent centers [Campinas (n = 441) and Vitória (n = 120)] by clinical history, physical examination, anthropometry, analysis of metabolic and echocardiography parameters as well as p22-phox C242T polymorphism genotyping. In addition, NADPH-oxidase activity was quantified in peripheral mononuclear cells from a subgroup of Campinas sample.

Results

Genotype frequencies in both samples were consistent with the Hardy- Weinberg equilibrium. Subjects with the T allele presented higher left ventricular mass/height2.7 than those carrying the CC genotype in Campinas (76.8 ± 1.6 vs 70.9 ± 1.4 g/m2.7; p = 0.009), and in Vitória (45.6 ± 1.9 vs 39.9 ± 1.4 g/m2.7; p = 0.023) samples. These results were confirmed by stepwise regression analyses adjusted for age, gender, blood pressure, metabolic variables and use of anti-hypertensive medications. In addition, increased NADPH-oxidase activity was detected in peripheral mononuclear cells from T allele carriers compared with CC genotype carriers (p = 0.03).

Conclusions

The T allele of the p22-phox C242T polymorphism is associated with higher left ventricular mass/height2.7 and increased NADPH-oxidase activity in Brazilian hypertensive patients. These data suggest that genetic variation within NADPH-oxidase components may modulate left ventricular remodeling in subjects with systemic hypertension.

Keywords:
p22-phox; left ventricle; hypertension; polymorphism; NADPH-oxidase