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

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.

Review A State of Natriuretic Peptide Deficiency

Measurement of natriuretic peptides (NPs) has proven its clinical value as biomarker, especially in the context of heart failure (HF). In contrast, a state partial NP deficiency appears integral to several conditions in which lower NP concentrations in plasma presage overt cardiometabolic disease. Here, obesity and type 2 diabetes have attracted considerable attention. Other factors - including age, sex, race, genetics, and diurnal regulation - affect the NP "armory" and may leave some individuals more prone to development of cardiovascular disease. The molecular maturation of NPs has also proven complex with highly variable O-glycosylation within the biosynthetic precursors. The relevance of this regulatory step in post-translational propeptide maturation has recently become recognized in biomarker measurement/interpretation and cardiovascular pathophysiology. An important proportion of people appear to have reduced effective net NP bioactivity in terms of receptor activation and physiological effects. The state of NP deficiency, then, both entails a potential for further biomarker development and could also offer novel pharmacological possibilities. Alleviating the state of NP deficiency before development of overt cardiometabolic disease in selected patients could be a future path for improving precision medicine.

Renal Corin Is Essential for Normal Blood Pressure and Sodium Homeostasis

Atrial natriuretic peptide (ANP)-mediated natriuresis is known as a cardiac endocrine function in sodium and body fluid homeostasis. Corin is a protease essential for ANP activation. Here, we studied the role of renal corin in regulating salt excretion and blood pressure. We created corin conditional knockout (cKO), in which the Corin gene was selectively disrupted in the kidney (kcKO) or heart (hcKO). We examined the blood pressure, urinary Na⁺ and Cl⁻ excretion, and cardiac hypertrophy in wild-type, corin global KO, kcKO, and hcKO mice fed normal- and high-salt diets. We found that on a normal-salt diet (0.3% NaCl), corin kcKO and hcKO mice had increased blood pressure, indicating that both renal and cardiac corin is necessary for normal blood pressure in mice. On a high-salt diet (4% NaCl), reduced urinary Na⁺ and Cl⁻ excretion, increased body weight, salt-exacerbated hypertension, and cardiac hypertrophy were observed in corin kcKO mice. In contrast, impaired urinary Na⁺ and Cl⁻ excretion and salt-exacerbated hypertension were not observed in corin hcKO mice. These results indicated that renal corin function is important in enhancing natriuresis upon high salt intakes and that this function cannot be compensated by the cardiac corin function in mice.

DNA Methylation of the Natriuretic Peptide System Genes and Ischemic Stroke: Gene-Based and Gene Set Analyses

Background and Objectives

The natriuretic peptide (NP) system has been considered an important regulator for ischemic stroke (IS) with a limited clinical implication. A better understanding of the underlying molecular mechanisms is urgent. Here, we aimed to examine the role of DNA methylation of NP system genes in IS.

Methods

DNA methylation at promoter regions of 4 core NP system genes, e.g., CORIN, FURIN, NPPA, and NPPB, was measured by targeted bisulfite sequencing in 853 patients with IS and 918 controls. We first examined the association between DNA methylation at each single CpG and IS, followed by gene-based and gene set analyses to examine the joint associations of DNA methylation at multiple CpGs in a gene or all 4 genes as a pathway with IS.

Results

After control of covariates and multiple testing, DNA methylation at 19 of the 36 assayed CpGs was individually associated with IS at q < 0.05. Higher average methylation levels at the targeted regions of CORIN (odds ratio [OR] = 0.64, 95% confidence interval [CI]: 0.56–0.73), FURIN (OR = 0.78, 95% CI: 0.69–0.88), and NPPA (OR = 0.78, 95% CI: 0.69–0.88) were associated with a lower odds of IS (all q < 0.05). The truncated product method revealed the same gene-based associations (all q < 0.05) and found that DNA methylation at all 4 NP system genes together was jointly associated with IS (p = 0.0001).

Discussion

DNA methylation at NP system genes was downregulated in patients with IS. Our results may unravel a molecular mechanism underlying the regulating effect of the NP system on IS and highlight the relevance of testing the joint effect of multiple CpGs in the epigenetic analysis.

Association between NPPA promoter methylation and hypertension: results from Gusu cohort and replication in an independent sample

Background

Atrial natriuretic peptide (ANP), one of the main members of the natriuretic peptides system, has been associated with hypertension and related complications, but the underlying molecular mechanisms are not very clear. Here, we aimed to examine whether DNA methylation, a molecular modification to the genome, of the natriuretic peptide A gene (NPPA), the coding gene of ANP, was associated with hypertension.

Methods

Peripheral blood DNA methylation of NPPA promoter was quantified by target bisulfite sequencing in 2498 community members (mean aged 53 years, 38% men) as a discovery sample and 1771 independent participants (mean aged 62 years, 54% men) as a replication sample. In both samples, we conducted a single CpG association analysis, followed by a gene-based association analysis, to examine the association between NPPA promoter methylation and hypertension, adjusting for age, sex, education level, cigarette smoking, alcohol consumption, obesity, fasting glucose, and lipids. Multiple testing was controlled by the false discovery rate approach.

Results

Of the 9 CpG loci assayed, hypermethylation at 5 CpGs (CpG1, CpG3, CpG6, CpG8, and CpG9) was significantly associated with a lower odds of prevalent hypertension in the discovery sample, and one CpG methylation (CpG1 located at Chr1:11908353) was successfully replicated in the replication sample (OR = 0.82, 95%CI 0.74–0.91, q = 0.002) after adjusting for covariates and multiple testing. The gene-based analysis found that DNA methylation of the 9 CpGs at NPPA promoter as a whole was significantly associated with blood pressure and prevalent hypertension in both samples (all P < 0.05).

Conclusions

DNA methylation levels at NPPA promoter were decreased in Chinese adults with hypertension. Aberrant DNA methylation of the NPPA gene may participate in the mechanisms of hypertension.

T2238C atrial natriuretic peptide gene variant and cardiovascular events in patients with atrial fibrillation: A substudy from the ATHERO-AF cohort

BACKGROUND

The T2238C variant of the atrial natriuretic peptide (ANP) gene has emerged as a novel risk factor for the incidence of cardiovascular events. However, the impact of this variant on cardiovascular outcome in patients with atrial fibrillation (AF) is unknown.

METHODS

We included 557 anticoagulated patients with non-valvular AF randomly selected from the prospective ATHERO-AF cohort. Patients underwent genetic analysis for the T2238C/ANP variant and were grouped as wild type or heterozygous or homozygous for C2238 variant allele. Primary endpoint was a composite of cardiovascular events (CVEs) including cardiovascular death, fatal/non-fatal ischemic stroke and myocardial infarction. Overall, 429 patients carried the TT wild type genotype, 110 patients (19.7%) were heterozygous (T/C) and 18 patients (3.2%) were homozygous (CC).

RESULTS

Incidence of CVEs was higher in homozygous patients for C2238 allele at unadjusted analysis (log-rank test, p = 0.042 for additive model, p = 0.043 for recessive model). The multivariable Cox proportional hazards regression analysis confirmed that C2238 ANP allele was associated with CVEs in the additive (p = 0.008) and recessive models (p = 0.005).

CONCLUSIONS

Carrier status for the C2238/ANP variant allele is associated with an increased risk of CVEs in anticoagulated AF patients.

Natriuretic Peptides in the Cardiovascular System: Multifaceted Roles in Physiology, Pathology and Therapeutics

The natriuretic peptides (NPs) family includes a class of hormones and their receptors needed for the physiological control of cardiovascular functions. The discovery of NPs provided a fundamental contribution into our understanding of the physiological regulation of blood pressure, and of heart and kidney functions. NPs have also been implicated in the pathogenesis of several cardiovascular diseases (CVDs), including hypertension, atherosclerosis, heart failure, and stroke. A fine comprehension of the molecular mechanisms dependent from NPs and underlying the promotion of cardiovascular damage has contributed to improve our understanding of the molecular basis of all major CVDs. Finally, the opportunity to target NPs in order to develop new therapeutic tools for a better treatment of CVDs has been developed over the years. The current Special Issue of the Journal covers all major aspects of the molecular implications of NPs in physiology and pathology of the cardiovascular system, including NP-based therapeutic approaches.

Cardiovascular Pleiotropic Effects of Natriuretic Peptides

Atrial natriuretic peptide (ANP) is a cardiac hormone belonging to the family of natriuretic peptides (NPs). ANP exerts diuretic, natriuretic, and vasodilatory effects that contribute to maintain water–salt balance and regulate blood pressure. Besides these systemic properties, ANP displays important pleiotropic effects in the heart and in the vascular system that are independent of blood pressure regulation. These functions occur through autocrine and paracrine mechanisms. Previous works examining the cardiac phenotype of loss-of-function mouse models of ANP signaling showed that both mice with gene deletion of ANP or its receptor natriuretic peptide receptor A (NPR-A) developed cardiac hypertrophy and dysfunction in response to pressure overload and chronic ischemic remodeling. Conversely, ANP administration has been shown to improve cardiac function in response to remodeling and reduces ischemia-reperfusion (I/R) injury. ANP also acts as a pro-angiogenetic, anti-inflammatory, and anti-atherosclerotic factor in the vascular system. Pleiotropic effects regarding brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) were also reported. In this review, we discuss the current evidence underlying the pleiotropic effects of NPs, underlying their importance in cardiovascular homeostasis.

Molecular Implications of Natriuretic Peptides in the Protection from Hypertension and Target Organ Damage Development

The pathogenesis of hypertension, as a multifactorial trait, is complex. High blood pressure levels, in turn, concur with the development of cardiovascular damage. Abnormalities of several neurohormonal mechanisms controlling blood pressure homeostasis and cardiovascular remodeling can contribute to these pathological conditions. The natriuretic peptide (NP) family (including ANP (atrial natriuretic peptide), BNP (brain natriuretic peptide), and CNP (C-type natriuretic peptide)), the NP receptors (NPRA, NPRB, and NPRC), and the related protease convertases (furin, corin, and PCSK6) constitute the NP system and represent relevant protective mechanisms toward the development of hypertension and associated conditions, such as atherosclerosis, stroke, myocardial infarction, heart failure, and renal injury. Initially, several experimental studies performed in different animal models demonstrated a key role of the NP system in the development of hypertension. Importantly, these studies provided relevant insights for a better comprehension of the pathogenesis of hypertension and related cardiovascular phenotypes in humans. Thus, investigation of the role of NPs in hypertension offers an excellent example in translational medicine. In this review article, we will summarize the most compelling evidence regarding the molecular mechanisms underlying the physiological and pathological impact of NPs on blood pressure regulation and on hypertension development. We will also discuss the protective effect of NPs toward the increased susceptibility to hypertensive target organ damage.