Interleukin 6(-174G/C) Variant and its Circulating Levels in Coronary Artery Disease Patients and Their First Degree Relatives

Abstract

Interleukin-6 (IL-6) a pleiotropic cytokine is a central mediator of inflammation in the pathogenesis of coronary artery disease (CAD). Our aim is to evaluate the serum levels of IL-6 and C-reactive protein (CRP) and to analyze the IL-6 polymorphism in CAD patients and to identify the first-degree relatives (FDRs) at risk of the disease in comparison with healthy controls. Estimation of IL-6 levels by enzyme-linked immunosorbent assay (ELISA) and CRP by latex reagent kit method, and genotyping of IL6 gene variants -174 (G>C) was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 600 subjects. IL-6 and CRP levels were significantly high in patients followed by FDRs compared to controls. The frequency of the IL-6 genotype was significantly different between cases, FDRs and controls and association of serum IL-6 levels with genotype found to be significant in CC genotype compared to GC and GG at p < 0.01 in CAD patients and FDRs, while there is no significant difference observed in controls. The study shows the importance of inflammation in the pathogenesis of CAD and predicts the risk of future coronary events in healthy asymptomatic FDRs.

Association of interleukin-6 gene polymorphism with coronary artery disease: an updated systematic review and cumulative meta-analysis

“…Recently, some metaanalyses suggested that IL-6 polymorphism (e.g., -174G/ C and -572G/C) is associated somewhat with CAD risk [54]. Although relevant meta-analysis gained summary results, several new studies reported conflicting results [36][37][38]. In the present study, the association was analyzed in Caucasian (including European and South Asian) and East Asian populations comprehensively, and the different associations were explained based on ethnicity.…”

“…It has been reported that IL-6 gene polymorphisms contribute significantly to CAD , but the results of previous studies were inconsistent. Although relevant meta-analysis gained summary results, several new studies reported conflicting results [36][37][38]. We designed the meta-analysis involving all previous eligible studies to assess the association of IL-6 polymorphisms with CAD.…”

IL-6-174G/C and IL-6-572C/G polymorphisms are associated with increased risk of coronary artery disease

“…Many epidemiologic studies have observed that polymorphisms in the genes encoding interleukin-1 receptor antagonist, such as , are associated with the development of CAD (Zhang et al, 2011;Huang et al, 2013;Opstad et al, 2011Opstad et al, , 2013Galimudi et al, 2014;He et al, 2014;Zhang et al, 2014).…”

“…One animal experimental study has shown that several cytokines play a key role in the development of CAD (Kleemann et al, 2008). Several previous epidemiology studies have shown that polymorphisms in several cytokines, including interleukin-6 (IL-6), , are involved in the pathogenesis of CAD (Zhang et al, 2011;Huang et al, 2013;Opstad et al, 2011Opstad et al, , 2013Galimudi et al, 2014;He et al, 2014;Zhang et al, 2014). However, the results of these studies are inconsistent.…”

Interleukin 6 promoter 174 G/C polymorphisms in acute ischemic stroke: G allele is protective but not associated with IL-6 levels or stroke outcome

“…genotypes [38]. There have been no studies of the effects of IL-6 promoter polymorphisms on IL-6 levels after stroke.…”