Association of 2238T>C polymorphism of the atrial natriuretic peptide gene with coronary artery disease in Afro-Caribbeans with type 2 diabetes

Atrial natriuretic peptide T2238C gene polymorphism and the risk of cardiovascular diseases: A meta‑analysis

The present study aimed to investigate the association between atrial natriuretic peptide (ANP) T2238C (rs5065) gene polymorphism and the risk of cardiovascular disease. Relevant literature was obtained by searching databases. The odds ratios (ORs) of the ANP T2238C locus genotype distribution in the case group of cardiovascular diseases and the control group of a non-cardiovascular population were pooled using R software. Sensitivity analysis was used to verify the stability of the results. Egger's linear regression test was used to assess the publication bias of the included literature. Studies were classified according to quality assessment score of the Newcastle-Ottawa scale, year, region, sample size and underlying disease for subgroup analysis, and meta-regression analysis was performed. A total of 12 studies comprising 45,619 patients were included. ANP rs5065 mutant gene C allele was a significant risk factor for myocardial infarction relative to T allele (OR=2.55, 95% CI=1.47-4.43, P=0.0008), CC+CT genotype was a significant risk factor for cerebrovascular events relative to TT (OR=1.14, 95% CI=1.04-1.26, P=0.0048) and the mutant CC genotype was a potential risk factor for the composite cardio-cerebral vascular events (CVE) relative to CT+TT (OR=1.40, 95% CI=0.96-2.04, P=0.081). In studies fulfilling the Hardy-Weinberg equilibrium, the CC genotype was a significant risk factor for the composite CVE relative to TT (OR=2.39, 95% CI=1.40-4.10, P=0.0018) and the CC genotype was a significant risk factor for composite CVE relative to CT+TT (OR=2.41, 95% CI=1.41-4.13, P=0.0015). The P-value of the Egger's test for publication bias was 0.436, which was not statistically significant. The results of the sensitivity analysis were relatively stable. Subgroup analysis indicated that the publication year was a potential source of heterogeneity. Regression analysis was performed for the recessive model in the composite CVE and the results showed that the study region (Europe) was one of the sources of heterogeneity (P=0.016). In conclusion, ANP 2238T/C mutation may increase the risk of myocardial infarction, cerebrovascular events and composite CVE.

The T2238C Human Atrial Natriuretic Peptide Molecular Variant and the Risk of Cardiovascular Diseases

Atrial natriuretic peptide (ANP) is a cardiac hormone which plays important functions to maintain cardio-renal homeostasis. The peptide structure is highly conserved among species. However, a few gene variants are known to fall within the human ANP gene. The variant rs5065 (T2238C) exerts the most substantial effects. The T to C transition at the 2238 position of the gene (13–23% allele frequency in the general population) leads to the production of a 30-, instead of 28-, amino-acid-long α-carboxy-terminal peptide. In vitro, CC2238/αANP increases the levels of reactive oxygen species and causes endothelial damage, vascular smooth muscle cells contraction, and increased platelet aggregation. These effects are achieved through the deregulated activation of type C natriuretic peptide receptor, the consequent inhibition of adenylate cyclase activity, and the activation of Giα proteins. In vivo, endothelial dysfunction and increased platelet aggregation are present in human subjects carrying the C2238/αANP allele variant. Several studies documented an increased risk of stroke and of myocardial infarction in C2238/αANP carriers. Recently, an incomplete response to antiplatelet therapy in ischemic heart disease patients carrying the C2238/αANP variant and undergoing percutaneous coronary revascularization has been reported. In summary, the overall evidence supports the concept that T2238C/ANP is a cardiovascular genetic risk factor that needs to be taken into account in daily clinical practice.

T2238C ANP gene variant and risk of recurrent acute coronary syndromes in an Italian cohort of ischemic heart disease patients

BACKGROUND

The role of C2238/atrial natriuretic peptide (ANP) minor allele, at the T2238C ANP gene variant, as a predisposing risk factor for acute cardiovascular events, has been previously reported. We aimed at evaluating, by a retrospective approach, the long-term impact of C2238/ANP-minor allele carrier status toward the risk of recurrent acute coronary syndromes (re-ACS) in an Italian cohort of ischemic heart disease patients.

METHODS

A total of 379 patients (males = 80.5%; mean age = 62.5 ± 9.2 years) presenting with ACS were retrospectively analyzed. Mean follow-up was 5.1 ± 3.5 years (range 1-26 years). Occurrence of new episodes of unstable angina, non-ST-segment elevation myocardial infarction and STE myocardial infarction over the years was recorded and compared between subjects not carrying and carrying C2238/ANP-minor allele.

RESULTS

At univariate analysis, C2238/ANP-minor allele carrier status and treatment with beta-blocker, aspirin and statin were associated with risk of re-ACS. Multivariate analysis confirmed that hypercholesterolemia (P < 0.0001) and C2238/ANP-minor allele carrier status (P < 0.05) were both significantly and independently associated with increased risk of re-ACS. Both treatments with beta-blocker and with statin were significantly associated with reduced risk of re-ACS (P = 0.01 and P < 0.01, respectively). Age above 55 years was associated with recurrence of ACS in C2238/ANP-minor allele carriers (hazard ratio 1.427, 95% confidence interval 1.066-1.911, P = 0.017). Kaplan-Meier curves confirmed highest risk of new events occurrence in C2238/ANP-minor allele carriers (P = 0.035).

CONCLUSIONS

The present results demonstrate that C2238/ANP-minor allele carrier status is an independent risk factor for ACS recurrence in an Italian cohort of ischemic heart disease patients over the long term, and they support the role of C2238/ANP-minor allele as a negative prognostic factor in coronary artery disease patients.

Sex Differences of the Natriuretic Peptide Polymorphism Associated With Angiographic Coronary Atherosclerosis

Background

Polymorphisms within natriuretic peptide (NP) genes have been associated with clinical outcomes for cardiovascular disease (CVD), but no previous study has compared the effect of these polymorphisms between men and women. This study aimed to investigate the association between single nucleotide polymorphisms (SNPs) in key genes of the NP system and coronary angiographic outcomes, with the focus on the sexual dimorphism in the effects of these SNPs.

Methods

Patients undergoing clinically indicated coronary angiography (n = 513, 328 men and 185 women) were consented and genotyped for NPPA rs5065, NPPB rs198389 and NPR2 rs10758325. Patients were stratified into having normal coronaries, non-obstructive coronary artery disease (CAD) or obstructive CAD, based on the highest stenosis in any epicardial artery. Average luminal narrowing across all four arteries was derived to represent the overall atherosclerotic burden.

Results

The frequency of NPPB rs198389 AA genotype was significantly higher in women with obstructive CAD (P = 0.014). The same association was not observed in males. With respect to atherosclerotic burden, an association was found between the AA genotype and average luminal narrowing in women (P = 0.005), but not in men.

Conclusions

The current study identified an association between an SNP of the NPPB gene and coronary atherosclerotic burden through angiographic evidence in women but not in men. These results suggest that B-type natriuretic peptide (BNP) may have more important involvement in the development of CAD in women compared to men, and as such, genotyping of the NPPB gene may serve as a potential biomarker to identify women with high risk for CAD.

Gene Polymorphisms of FABP2, ADIPOQ and ANP and Risk of Hypertriglyceridemia and Metabolic Syndrome in Afro-Caribbeans

OBJECTIVES

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities and cardiovascular risk factors that are highly heritable and polygenic. We investigated the association of allelic variants of three candidate genes, rs1799883-FABP2, rs1501299-ADIPOQ and rs5065-ANP with MetS and its components, individually and in combination, using a genetic risk score.

METHODS

A cross-sectional study was conducted in 462 Afro-Caribbeans subjects without cardiovascular complications or lipid-lowering medications. Cardiovascular risk factors and MetS components (NCEP-ATPIII criteria) were recorded. The 3 SNPs were genotyped. The genetic risk score was calculated by summing the number of risk alleles at each locus. Logistic regressions were used.

RESULTS

Fifty-eight participants (12.6%) were diabetics and 116 (25.1%) had a MetS. In a dominant model, rs1799883 was associated with hypertriglyceridemia (OR 2.22; P = 0.014) and hypertriglyceridemic waist (HTGW), (P = 0.014) but not significantly with overweight (P = 0.049), abdominal obesity (P = 0.033) and MetS (P = 0.068). In a dominant model, the OR of MetS and HTGW for rs1501299 were 1.80 (P = 0.028) and 2.19 (P = 0.040) respectively. In a recessive model, the OR of hypertriglyceridemia for rs5065 was 1.94 (P = 0.075). The genetic risk score was significantly associated with MetS. Subjects carrying 4-5 risk alleles (18.8%) had a nearly 2.5-fold-increased risk of MetS compared to those carrying 0-1 risk allele (24.3%): OR 2.31; P = 0.025.

CONCLUSIONS

This study supports the association of FABP2, ANP and ADIPOQ gene variants with MetS or its components in Afro-Caribbeans and suggests a cumulative genetic influence of theses variants on this syndrome and a potential effect on lipid metabolism.

SNP-SNP Interaction between TLR4 and MyD88 in Susceptibility to Coronary Artery Disease in the Chinese Han Population

The toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-dependent signaling pathway plays a role in the initiation and progression of coronary artery disease (CAD). We investigated SNP-SNP interactions between the TLR4 and MyD88 genes in CAD susceptibility and assessed whether the effects of such interactions were modified by confounding risk factors (hyperglycemia, hyperlipidemia and Helicobacter pylori (H. pylori) infection). Participants with CAD (n = 424) and controls (n = 424) without CAD were enrolled. Polymerase chain restriction-restriction fragment length polymorphism was performed on genomic DNA to detect polymorphisms in TLR4 (rs10116253, rs10983755, and rs11536889) and MyD88 (rs7744). H. pylori infections were evaluated by enzyme-linked immunosorbent assays, and the cardiovascular risk factors for each subject were evaluated clinically. The significant interaction between TLR4 rs11536889 and MyD88 rs7744 was associated with an increased CAD risk (p value for interaction = 0.024). In conditions of hyperglycemia, the interaction effect was strengthened between TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.004). In hyperlipidemic participants, the interaction strength was also enhanced for TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.006). Thus, the novel interaction between TLR4 rs11536889 and MyD88 rs7744 was related with an increased risk of CAD, that could be strengthened by the presence of hyperglycemia or hyperlipidemia.