Interleukin-6 Promoter Polymorphisms and Susceptibility to Atrial Fibrillation in Elderly Han Chinese Patients with Essential Hypertension

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.

Serum YKL-40 is increased in patients with slow coronary flow

“…Current smoking, hypertension, diabetes mellitus, and atrial fibrillation were defined according to past literature reports [13][14][15]. Details of medical history, as well as physical and laboratory examination, were obtained from all patients before performing the coronary angiography.…”

“…The measurement of total cholesterol, high-density lipoprotein-cholesterol, lowdensity lipoprotein-cholesterol, triglycerides, and hs-CRP was performed as described previously [14][15][16]. Blood samples for high-sensitivity C-reactive protein (hs-CRP) and YKL-40 were drawn from the radial sheath before selective coronary angiography was performed.…”

Angiotensin-converting enzyme gene 2350 G/A polymorphism and susceptibility to atrial fibrillation in Han Chinese patients with essential hypertension

“…The samples were then centrifuged at 2500 rpm for 30 minutes at 4°C and immediately stored at -80°C until analysis. The measurement of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and triglycerides (TG) was performed as described previously (7,19). …”

“…The prevalence of AF is strongly age-dependent, affecting approximately 0.5% of persons aged 40-50 years old and 5-15% of individuals aged 80 years old (3,7). In China, the morbidity related to AF is 0.77% in the adult population (8).…”

Genomics of Atrial Fibrillation

“…However, data regarding a polymorphism in the CRP gene, which has been reported in candidate gene analysis as an independent risk factor for stroke, have been conflicting [122, 123]. Other components of the inflammatory cascade studied include IL-1a, TNFα, IL-10, ICAM-1, though evidence has again been inconsistent [124–128] with studies limited by heterogeneity and small sample size.…”