IL-1 cluster genes and occurrence of post-percutaneous transluminal coronary angioplasty restenosis: a prospective, angiography-based evaluation

Systematic testing of literature reported genetic variation associated with coronary restenosis: results of the GENDER Study

Background

Coronary restenosis after percutaneous coronary intervention still remains a significant problem, despite all medical advances. Unraveling the mechanisms leading to restenosis development remains challenging. Many studies have identified genetic markers associated with restenosis, but consistent replication of the reported markers is scarce. The aim of the current study was to analyze the joined effect of previously in literature reported candidate genes for restenosis in the GENetic DEterminants of Restenosis (GENDER) databank.

Methodology/Principal Findings

Candidate genes were selected using a MEDLINE search including the terms ‘genetic polymorphism’ and ‘coronary restenosis’. The final set included 36 genes. Subsequently, all single nucleotide polymorphisms (SNPs) in the genomic region of these genes were analyzed in GENDER using set-based analysis in PLINK. The GENDER databank contains genotypic data of 2,571,586 SNPs of 295 cases with restenosis and 571 matched controls. The set, including all 36 literature reported genes, was, indeed, significantly associated with restenosis, p = 0.024 in the GENDER study. Subsequent analyses of the individual genes demonstrated that the observed association of the complete set was determined by 6 of the 36 genes.

Conclusion

Despite overt inconsistencies in literature, with regard to individual candidate gene studies, this is the first study demonstrating that the joint effect of all these genes together, indeed, is associated with restenosis.

The role of IL-1 in the pathogenesis of heart disease

Interleukin (IL)-1 consists of two distinct ligands, IL-1alpha and IL-1beta, with indistinguishable biological activities that signal through the IL-1 type I receptor (IL-1RI). A naturally occurring IL-1 receptor antagonist (IL-1Ra) binds to IL-1RI without initiating signal transduction and prevents IL-1 signaling, competitively inhibiting IL-1-mediated responses. Emerging evidence suggests that the balance between IL-1 agonists and antagonists plays an essential role in a variety of cardiovascular conditions. IL-1 may play a role in atherothrombotic disease by promoting the formation of atheromatous lesions, enhancing vascular inflammation, and triggering plaque destabilization. Following myocardial infarction, IL-1 critically regulates the inflammatory response and is involved in the development of adverse remodeling by enhancing expression of matrix metalloproteinases. IL-1 signaling may also be an essential mediator in the pathogenesis of heart failure by suppressing cardiac contractility, promoting myocardial hypertrophy, and inducing cardiomyocyte apoptosis. The present review summarizes current available data showing the significant role of IL-1 signaling in heart disease and raising the possibility that IL-1 inhibitors (such as anakinra, a nonglycosylated recombinant human IL-1Ra) may be clinically useful agents in patients with certain cardiovascular conditions.

Common variants in interleukin-1-Beta gene are associated with intracranial hemorrhage and susceptibility to brain arteriovenous malformation

BACKGROUND

Polymorphisms in the proinflammatory cytokine interleukin (IL)-1beta gene have been associated with systemic atherogenesis, thrombosis and rupture. The aim of this study was to investigate associations between single nucleotide polymorphisms (SNPs) in IL-1beta and intracranial hemorrhage (ICH) in the natural course of brain arteriovenous malformation (BAVM) patients.

METHOD

Two IL-1beta promoter SNPs (-511C-->T, -31T-->C) and 1 synonymous coding SNP in exon 5 at +3953C-->T (Phe) were genotyped in 410 BAVM patients. We performed a survival analysis of time to subsequent ICH, censoring cases at first treatment, death or last follow-up. A Cox regression analysis was performed to obtain hazard ratios (HRs) for genotypes adjusted for age, sex, Caucasian race/ethnicity and hemorrhagic presentation.

RESULTS

Subjects with the -31 CC genotype (HR = 2.7; 95% CI 1.1-6.6; p = 0.029) or the -511 TT genotype (HR = 2.6; 95% CI 1.1-6.5; p = 0.039) had a greater risk of subsequent ICH compared with reference genotypes, adjusting for covariates. The +3953C-->T SNP was not significantly associated with an increased ICH risk (p = 0.22). The IL-1beta promoter polymorphisms were also associated with BAVM susceptibility among a subset of 235 BAVM cases and 255 healthy controls of Caucasian race/ethnicity (p < 0.001).

CONCLUSION

IL-1beta promoter polymorphisms were associated with an increased risk of ICH in BAVM clinical course and with BAVM susceptibility. These results suggest that inflammatory pathways, including the IL-1beta cytokine, may play an important role in ICH.

The interleukin 1B-511 polymorphism is associated with the risk of developing restenosis after coronary stenting in Mexican patients

Inflammation is the primary response to vessel wall injury caused by stent placement in coronary arteries. Cytokines of the interleukin-1 family are central regulators in immunoinflammatory mechanisms. The objective of this study was to test for association between IL-1 family gene polymorphisms and risk for restenosis after coronary stent placement. The IL-1B-511, IL-1F10.3, RN.4T>C, RN.6/1C>T, RN.6/2C>G, and IL-1RN VNTR polymorphisms were analyzed by 5' exonuclease TaqMan genotyping assays and polymerase chain reaction in a group of 165 patients who underwent coronary artery stenting. Basal and procedure coronary angiography were analyzed in search of angiographic predictors of restenosis and follow-up angiography was analyzed in search of binary restenosis. Patients with IL-1B-511 TT genotype had a 1.89-fold increased risk of developing restenosis. The analysis considering the lesions treated demonstrated that the lesions of patients with IL-1B-511 TT genotype had a 3.44-fold increased risk of developing restenosis. When the analysis considered the type of stent, the risk of developing restenosis was increased in lesions of patients with TT genotype (odds ratio = 4.50) who underwent coronary bare-metal stent implantation. Multiple logistic analysis identified IL-1B-511 TT genotype as an independent predictor for restenosis. The results suggest that IL-1B-511 polymorphism could be involved in the risk of developing restenosis after coronary stent placement.

Interleukin 1 genetics, inflammatory mechanisms, and nutrigenetic opportunities to modulate diseases of aging

Inflammation plays a central role in many diseases of aging, and genetic differences in the inflammatory response appear to influence different disease courses among individuals. Variations in the genes for the family of interleukin 1 (IL-1) proteins are inherited together in a small set of patterns and provide an example of the role of inflammatory genetics as a modifier of diseases of aging. The IL-1 genetic variations are associated with variation in both the inflammatory response and the clinical presentation of a range of diseases, including coronary artery disease, Alzheimer disease, gastric cancer, and periodontitis. This growing understanding of the role of genetic variation in inflammation and chronic disease presents opportunities to identify healthy persons who are at increased risk of disease and to potentially modify the trajectory of disease to prolong healthy aging. Nutrition represents one of the promising approaches to modulation of the risk of diseases of aging because of the effects of certain nutrients on gene expression. One of the most practical applications of nutritional modulation of chronic disease may be nutrients that regulate the expression of key inflammatory genes.