Interleukin-6 -634C>G polymorphism in hypertensive patients with and without left ventricular hypertrophy.
ABSTRACT There is an accumulating body of evidence indicating that inflammation plays a pivotal role in the pathogenesis of cardiovascular disease. Interleukin-6 (IL-6) is a pleiotropic cytokine secreted by many cells of the immune system, cardiovascular components and adipose tissue, and functions as a mediator of inflammatory response with both pro- and anti-inflammatory properties. Circulating levels of IL-6 differ greatly between individuals due to both genetic and environmental factors. The IL-6 -634C>G polymorphism is common in eastern Asian populations. The aim of the present study was to investigate the association of this polymorphism with essential hypertension (EH) and left ventricular hypertrophy (LVH) in 440 subjects (246 EH patients and 194 controls) from a Han Chinese population. In this study, IL-6 -634C>G genotypes were identified by polymerase chain reaction and restriction digestion in all study participants, and left ventricular mass was assessed by 2-mode echocardiography in 178 untreated EH patients. There was no significant difference in either genotype distribution (p=0.9528) or allele frequency (p=0.7775) between the EH and control groups. In addition, the -634C>G polymorphism had no effect on blood pressure in either the controls or the untreated EH patients. No significant differences in genotype distribution (p=0.7998) or allele frequency distribution (p=0.5468) were found between EH patients with and without LVH. Moreover, the echocardiographic parameters were not statistically different between the CC and CG+GG genotypes. These findings suggest that there is no association of the IL-6 -634C>G polymorphism and EH with LVH in EH patients.
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ABSTRACT: There is an accumulating body of evidence indicating a strong association between inflammation and the pathogenesis of atrial fibrillation (AF). Interleukin-6 (IL-6) is a pleiotropic cytokine, functions as a mediator of inflammatory response, and has both proinflammatory and anti-inflammatory properties. The aim of the present study was to investigate the association of the -634C/G polymorphism of the IL-6 gene with AF in elderly Han Chinese patients with essential hypertension (EH). A total of 169 elderly patients with EH were eligible for this study. Patients with AF (n=75) were allocated to the AF group, and 94 subjects without AF to the control group. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotype frequencies. The distribution of the IL-6 -634C/G genotypes (CC, CG, and GG) was 67.02%, 30.85%, and 2.13% in the controls, and 50.67%, 40.00%, and 9.33% in AF subjects, respectively (P=0.0312). The frequency of the G allele in the AF group was significantly higher than that in the control group (29.33% vs. 17.55%, P=0.0103). Compared with the CC and CG genotypes, the GG homozygote had a 4.7353-fold increased risk of AF [95% confidence interval (CI)=0.9537-23.5116, P=0.0382]. These findings suggest that the IL-6 -634C/G polymorphism is associated with AF, and the G allele has increased risk of AF in elderly Han Chinese patients with EH.Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 08/2012; · 1.63 Impact Factor