The multidimensional value of natriuretic peptides in heart failure, integrating laboratory and clinical aspects.

Natriuretic peptides (NP) play an essential role in heart failure (HF) regulation, and their measurement has improved diagnostic and prognostic accuracy. Clinical symptoms and objective measurements, such as NP levels, should be included in the HF definition to render it more reliable and consistent among observers, hospitals, and healthcare systems. BNP and NT-proBNP are reasonable surrogates for cardiac disease, and their measurement is critical to early diagnosis and risk stratification of HF patients. NPs should be measured in all patients presenting with dyspnea or other symptoms suggestive of HF to facilitate early diagnosis and risk stratification. Both BNP and NT-proBNP are currently used for guided HF management and display comparable diagnostic and prognostic accuracy. Standardized cutoffs for each NP assay are essential for data comparison. The value of NP testing is recognized at various levels, including patient empowerment and education, analytical and operational issues, clinical HF management, and cost-effectiveness.

Patient phenotype profiling using echocardiography and natriuretic peptides to personalise heart failure therapy.

Heart failure (HF) is a progressive condition with a clinical picture resulting from reduced cardiac output (CO) and/or elevated left ventricular (LV) filling pressures (LVFP). The original Diamond-Forrester classification, based on haemodynamic data reflecting CO and pulmonary congestion, was introduced to grade severity, manage, and risk stratify advanced HF patients, providing evidence that survival progressively worsened for those classified as warm/dry, cold/dry, warm/wet, and cold/wet. Invasive haemodynamic evaluation in critically ill patients has been replaced by non-invasive haemodynamic phenotype profiling using echocardiography. Decreased CO is not infrequent among ambulatory HF patients with reduced ejection fraction, ranging from 23 to 45%. The Diamond-Forrester classification may be used in combination with the evaluation of natriuretic peptides (NPs) in ambulatory HF patients to pursue the goal of early identification of those at high risk of adverse events and personalise therapy to antagonise neurohormonal systems, reduce congestion, and preserve tissue/renal perfusion. The most benefit of the Guideline-directed medical treatment is to be expected in stable patients with the warm/dry profile, who more often respond with LV reverse remodelling, while more selective individualised treatments guided by echocardiography and NPs are necessary for patients with persisting congestion and/or tissue/renal hypoperfusion (cold/dry, warm/wet, and cold/wet phenotypes) to achieve stabilization and to avoid further neurohormonal activation, as a result of inappropriate use of vasodilating or negative chronotropic drugs, thus pursuing the therapeutic objectives. Therefore, tracking the haemodynamic status over time by clinical, imaging, and laboratory indicators helps implement therapy by individualising drug regimens and interventions according to patients' phenotypes even in an ambulatory setting.

Haemodynamic, hormonal and renal actions of osteocrin in normal sheep.

Osteocrin (OSTN) is an endogenous protein sharing structural similarities with the natriuretic peptides [NPs; atrial (ANP), B-type (BNP) and C-type (CNP) NP], which are hormones known for their crucial role in maintaining pressure/volume homeostasis. Osteocrin competes with the NPs for binding to the receptor involved in their clearance (NPR-C). In the present study, having identified, for the first time, the major circulating form of OSTN in human and ovine plasma, we examined the integrated haemodynamic, endocrine and renal effects of vehicle-controlled incremental infusions of ovine proOSTN (83-133) and its metabolism in eight conscious normal sheep. Incremental i.v. doses of OSTN produced stepwise increases in circulating concentrations of the peptide, and its metabolic clearance rate was inversely proportional to the dose. Osteocrin increased plasma levels of ANP, BNP and CNP in a dose-dependent manner, together with concentrations of their intracellular second messenger, cGMP. Increases in plasma cGMP were associated with progressive reductions in arterial pressure and central venous pressure. Plasma cAMP, renin and aldosterone were unchanged. Despite significant increases in urinary cGMP levels, OSTN administration was not associated with natriuresis or diuresis in normal sheep. These results support OSTN as an endogenous ligand for NPR-C in regulating plasma concentrations of NPs and associated cGMP-mediated bioactivity. Collectively, our findings support a role for OSTN in maintaining cardiovascular homeostasis.

Cardiovascular risk evaluation in pregnancy: focus on cardiac specific biomarkers.

Despite the evidence demonstrating the clinical utility of cardiac specific biomarkers in improving cardiovascular risk evaluation in several clinical conditions, even the most recent reviews and guidelines fail to consider their measurement in order to enhance the accuracy of the evaluation of cardiovascular risk in pregnant women. The aim of this review article was to examine whether the assay of cardiac specific biomarkers can enhance cardiovascular risk evaluation in pregnant women, first by reviewing the relationships between the physiological state of pregnancy and cardiac specific biomarkers. The clinical relevance of brain natriuretic peptide (BNP)/NT-proBNP and high-sensitivity cardiac troponin I/high-sensitivity cardiac troponin T (hs-cTnI/hs-cTnT) assay in improving cardiovascular risk evaluation is examined based on the results of clinical studies on subjects with normal and those with complicated pregnancy. Finally, the analytical approaches and clinical objectives related to cardio specific biomarkers are advocated in order to allow an early and more accurate evaluation of cardiovascular risk in pregnant women.

Discovery of small molecule guanylyl cyclase A receptor positive allosteric modulators.

The particulate guanylyl cyclase A receptor (GC-A), via activation by its endogenous ligands atrial natriuretic peptide (ANP) and b-type natriuretic peptide (BNP), possesses beneficial biological properties such as blood pressure regulation, natriuresis, suppression of adverse remodeling, inhibition of the renin-angiotensin-aldosterone system, and favorable metabolic actions through the generation of its second messenger cyclic guanosine monophosphate (cGMP). Thus, the GC-A represents an important molecular therapeutic target for cardiovascular disease and its associated risk factors. However, a small molecule that is orally bioavailable and directly targets the GC-A to potentiate cGMP has yet to be discovered. Here, we performed a cell-based high-throughput screening campaign of the NIH Molecular Libraries Small Molecule Repository, and we successfully identified small molecule GC-A positive allosteric modulator (PAM) scaffolds. Further medicinal chemistry structure-activity relationship efforts of the lead scaffold resulted in the development of a GC-A PAM, MCUF-651, which enhanced ANP-mediated cGMP generation in human cardiac, renal, and fat cells and inhibited cardiomyocyte hypertrophy in vitro. Further, binding analysis confirmed MCUF-651 binds to GC-A and selectively enhances the binding of ANP to GC-A. Moreover, MCUF-651 is orally bioavailable in mice and enhances the ability of endogenous ANP and BNP, found in the plasma of normal subjects and patients with hypertension or heart failure, to generate GC-A-mediated cGMP ex vivo. In this work, we report the discovery and development of an oral, small molecule GC-A PAM that holds great potential as a therapeutic for cardiovascular, renal, and metabolic diseases.

Endocrine functions of the heart: from bench to bedside.

Heart has a recognized endocrine function as it produces several biologically active substances with hormonal properties. Among these hormones, the natriuretic peptide (NP) system has been extensively characterized and represents a prominent expression of the endocrine function of the heart. Over the years, knowledge about the mechanisms governing their synthesis, secretion, processing, and receptors interaction of NPs has been intensively investigated. Their main physiological endocrine and paracrine effects on cardiovascular and renal systems are mostly mediated through guanylate cyclase-A coupled receptors. The potential role of NPs in the pathophysiology of heart failure and particularly their counterbalancing action opposing the overactivation of renin-angiotensin-aldosterone and sympathetic nervous systems has been described. In addition, NPs are used today as key biomarkers in cardiovascular diseases with both diagnostic and prognostic significance. On these premises, multiple therapeutic strategies based on the biological properties of NPs have been attempted to develop new cardiovascular therapies. Apart from the introduction of the class of angiotensin receptor/neprilysin inhibitors in the current management of heart failure, novel promising molecules, including M-atrial natriuretic peptide (a novel atrial NP-based compound), have been tested for the treatment of human hypertension. The development of new drugs is currently underway, and we are probably only at the dawn of novel NPs-based therapeutic strategies. The present article also provides an updated overview of the regulation of NPs synthesis and secretion by microRNAs and epigenetics as well as interactions of cardiac hormones with other endocrine systems.

Stroke in patients with heart failure and reduced or preserved ejection fraction.

AIMS: Stroke is an important problem in patients with heart failure (HF), but the intersection between the two conditions is poorly studied across the range of ejection fraction. The prevalence of history of stroke and related outcomes were investigated in patients with HF. METHODS AND RESULTS: Individual patient meta-analysis of seven clinical trials enrolling patients with HF with reduced (HFrEF) and preserved ejection fraction (HFpEF). Of the 20 159 patients with HFrEF, 1683 (8.3%) had a history of stroke, and of the 13 252 patients with HFpEF, 1287 (9.7%) had a history of stroke. Regardless of ejection fraction, patients with a history of stroke had more vascular comorbidity and worse HF. Among those with HFrEF, the incidence of the composite of cardiovascular death, HF hospitalization, stroke, or myocardial infarction was 18.23 (16.81-19.77) per 100 person-years in those with prior stroke vs. 13.12 (12.77-13.48) in those without [hazard ratio 1.37 (1.26-1.49), P < 0.001]. The corresponding rates in patients with HFpEF were 14.16 (12.96-15.48) and 9.37 (9.06-9.70) [hazard ratio 1.49 (1.36-1.64), P < 0.001]. Each component of the composite was more frequent in patients with stroke history, and the risk of future stroke was doubled in patients with prior stroke. Among patients with prior stroke, 30% with concomitant atrial fibrillation were not anticoagulated, and 29% with arterial disease were not taking statins; 17% with HFrEF and 38% with HFpEF had uncontrolled systolic blood pressure (≥140 mmHg). CONCLUSION: Heart failure patients with a history of stroke are at high risk of subsequent cardiovascular events, and targeting underutilization of guideline-recommended treatments might be a way to improve outcomes in this high-risk population.

A polygenic risk score predicts atrial fibrillation in cardiovascular disease.

AIMS: Interest in targeted screening programmes for atrial fibrillation (AF) has increased, yet the role of genetics in identifying patients at highest risk of developing AF is unclear. METHODS AND RESULTS: A total of 36,662 subjects without prior AF were analyzed from four TIMI trials. Subjects were divided into quintiles using a validated polygenic risk score (PRS) for AF. Clinical risk for AF was calculated using the CHARGE-AF model. Kaplan-Meier event rates, adjusted hazard ratios (HRs), C-indices, and net reclassification improvement were used to determine if the addition of the PRS improved prediction compared with clinical risk and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Over 2.3 years, 1018 new AF cases developed. AF PRS predicted a significant risk gradient for AF with a 40% increased risk per 1-SD increase in PRS [HR: 1.40 (1.32-1.49); P < 0.001]. Those with high AF PRS (top 20%) were more than two-fold more likely to develop AF [HR 2.45 (1.99-3.03), P < 0.001] compared with low PRS (bottom 20%). Furthermore, PRS provided an additional gradient of risk stratification on top of the CHARGE-AF clinical risk score, ranging from a 3-year incidence of 1.3% in patients with low clinical and genetic risk to 8.7% in patients with high clinical and genetic risk. The subgroup of patients with high clinical risk, high PRS, and elevated NT-proBNP had an AF risk of 16.7% over 3 years. The C-index with the CHARGE-AF clinical risk score alone was 0.65, which improved to 0.67 (P < 0.001) with the addition of NT-proBNP, and increased further to 0.70 (P < 0.001) with the addition of the PRS. CONCLUSION: In patients with cardiovascular conditions, AF PRS is a strong independent predictor of incident AF that provides complementary predictive value when added to a validated clinical risk score and NT-proBNP.

Left Ventricular Mass Index Predicts Renal Function Decline in Patients with Chronic Kidney Disease.

Background and Objectives: Several studies revealed a relation between abnormal cardiac remodeling and glomerular filtration rate (GFR) decline, but there are limited data regarding echocardiographic changes in chronic kidney disease (CKD). This study evaluated the abnormal cardiac structures characterizing patients with CKD, assessing the independent association between echocardiographic parameters and the risk of decline in renal function. Materials and Methods: In total, 160 patients with CKD were studied. All patients underwent an echocardiographic exam and 99mTc-DTPA renal scintigraphy to measure the GFR. After the baseline assessments, patients were followed prospectively for 12 months, or until the endpoint achievement, defined as a worsening in renal function (doubling of baseline serum creatinine, GFR decline ≥25%, the start of dialysis). Results: Patients with GFR values of 34.8 ± 15 mL/min, identifying stages III-IV of CKD, were associated with high levels of left ventricular mass index (LVMi) (101.9 ± 12.2 g/m2), which was related to proteinuria, systolic blood pressure, and pulmonary artery systolic pressure in a multiple regression model. During the observational period, 26% of patients reached the endpoint. Regression analysis revealed LVMi as a predictor of change in renal function after adjusting for kidney and cardiac risk factors. Multiple Cox regression indicated that an increase in LVMi was associated with a 12% increased risk of kidney disease progression (HR: 1.12; 95% CI: 1.04-1.16; p = 0.001). Conclusions: In patients with CKD, high LVMi represents an independent predictor of the progressive decline of the renal function, until the start of renal replacement therapy. Echocardiography can help identify patients at high risk for renal disease worsening in patients with CKD independently of clinical cardiac involvement.

GPx3 deficiency exacerbates maladaptive right ventricular remodeling in experimental pulmonary artery banding.

The stressed right ventricle (RV) is particularly susceptible to producing and accumulating reactive oxygen species, leading to extracellular matrix deposition and secretion of natriuretic peptides. The role of specific enzymes with antioxidative capacity, like glutathione peroxidase 3 (GPx3), in RV pathogenesis is currently unknown. Here, we use a murine model of pulmonary artery banding (PAB) to study the role of GPx3 in isolated RV pathology. Compared with wild-type (WT) mice undergoing PAB surgery, GPx3-deficient PAB mice presented with higher RV systolic pressure and higher LV eccentricity indices. PAB-induced changes in Fulton's Index, RV free wall thickness, and RV fractional area change were more pronounced in GPx3-deficient mice compared with WT controls. Adverse RV remodeling was enhanced in GPx3-deficient PAB animals, evidenced by increased RV expression levels of connective tissue growth factor (CTGF), transforming growth factor-ß (TGF-ß), and atrial natriuretic peptide (ANP). In summary, GPx3 deficiency exacerbates maladaptive RV remodeling and causes signs of RV dysfunction.

Inhibitory action of B-type natriuretic peptide on adrenocorticotropic hormone in patients with acute coronary syndrome.

In addition to the classical actions of hemodynamic regulation, natriuretic peptides (NPs) interact with various neurohumoral factors that are deeply involved in the pathophysiology of cardiovascular diseases. However, their effects on the hypothalamic-pituitary-adrenal (HPA) axis, which is activated under acute high-stress conditions in acute coronary syndrome (ACS), remain largely unknown. We investigated the impact of plasma B-type NP (BNP) on plasma adrenocorticotropic hormone (ACTH)-cortisol levels during the acute phase of ACS ischemic attacks. The study population included 436 consecutive patients with ACS for whom data were collected during emergency cardiac catheterization. Among them, biochemical data after acute-phase treatment were available in 320 cases, defined as the ACS-remission phase (ACS-rem). Multiple regression analyses revealed that plasma BNP levels were significantly negatively associated with plasma ACTH levels only during ACS attacks (P < 0.001), but not in ACS-rem, whereas plasma BNP levels were not significantly associated with plasma cortisol levels at any point. Accordingly, covariance structure analyses were performed to clarify the direct contribution of BNP to ACTH by excluding other confounding factors, confirming that BNP level was negatively correlated with ACTH level only during ACS attacks (ß = -0.152, P = 0.002), whereas BNP did not significantly affect ACTH in ACS-rem. In conclusion, despite the lack of a significant direct association with cortisol levels, BNP negatively regulated ACTH levels during the acute phase of an ACS attack in which the HPA axis ought to be activated. NP may alleviate the acute stress response induced by severe ischemic attacks in patients with ACS.NEW & NOTEWORTHY BNP negatively regulates ACTH during a severe ischemic attack of ACS in which hypothalamic-pituitary-adrenal axis ought to be activated, indicating an important role of natriuretic peptides as a mechanism of adaptation to acute critical stress conditions in humans.

Sex-based differences in metabolic protection by the ANP genetic variant rs5068 in the general population.

Atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) are produced in the heart and secreted into the circulation. As hormones, both peptides activate the guanylyl cyclase receptor A (GC-A), playing a role in blood pressure (BP) regulation. A significant role for ANP and BNP includes favorable actions in metabolic homeostasis. Sex-based high prevalence of risk factors for cardiovascular disease in males compared with females is well established, but sex-based differences on cardiometabolic protection have not been investigated in relation to ANP (NPPA) and BNP (NPPB) gene variants. We included 1,146 subjects in the general population from Olmsted County, Minnesota. Subjects were genotyped for the ANP gene variant rs5068 and BNP gene variant rs198389. Cardiometabolic parameters and medical records were reviewed. In the presence of the minor allele of rs5068, diastolic BP, creatinine, body mass index (BMI), waist measurement, insulin, and prevalence of obesity and metabolic syndrome were lower, whereas HDL was higher in males with only trends observed in females. We observed no associations of the minor allele with echocardiographic parameters in either males or females. Regarding rs198389 genotype, the minor allele was not associated with any BP, metabolic, renal, or echocardiographic parameters in either sex. In the general community, the minor allele of the ANP gene variant rs5068 is associated with a favorable metabolic phenotype in males. No associations were observed with the BNP gene variant rs198389. These studies support a protective role of the ANP pathway on metabolic function and underscore the importance of sex in relationship to natriuretic peptide responses.NEW & NOTEWORTHY Males are characterized by lower ANP and BNP with greater prevalence of cardiometabolic disease. The ANP genetic variant rs5068 was associated with less metabolic dysfunction in males, whereas no metabolic profile was related to the BNP genetic variant rs198389 in the general population. ANP may play a more biological role in metabolic homeostasis compared with BNP in the general population with greater physiological metabolic actions in males compared with females.

Natriuretic Peptides: Role in the Diagnosis and Management of Heart Failure: A Scientific Statement From the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America and Japanese Heart Failure Society.

Natriuretic peptides, brain (B-type) natriuretic peptide (BNP) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) are globally and most often used for the diagnosis of heart failure (HF). In addition, they can have an important complementary role in the risk stratification of its prognosis. Since the development of angiotensin receptor neprilysin inhibitors (ARNIs), the use of natriuretic peptides as therapeutic agents has grown in importance. The present document is the result of the Trilateral Cooperation Project among the Heart Failure Association of the European Society of Cardiology, the Heart Failure Society of America and the Japanese Heart Failure Society. It represents an expert consensus that aims to provide a comprehensive, up-to-date perspective on natriuretic peptides in the diagnosis and management of HF, with a focus on the following main issues: (1) history and basic research: discovery, production and cardiovascular protection; (2) diagnostic and prognostic biomarkers: acute HF, chronic HF, inclusion/endpoint in clinical trials, and natriuretic peptides-guided therapy; (3) therapeutic use: nesiritide (BNP), carperitide (ANP) and ARNIs; and (4) gaps in knowledge and future directions.

Association Between Change in Ambulatory Pulmonary Artery Pressures and Natriuretic Peptides in Patients with Heart Failure: Results From the EMBRACE-HF Trial.

BACKGROUND: Remote monitoring of pulmonary artery (PA) pressures and serial N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements guide heart failure (HF) treatment, but their association has yet to be described. METHODS AND RESULTS: In the Empagliflozin Evaluation by Measuring the Impact on Hemodynamics in Patients with Heart Failure (EMBRACE-HF) trial, patients with HF and a remote PA pressure monitoring device were randomized to empagliflozin vs placebo. PA diastolic pressures (PADP) and NT-proBNP levels were obtained at baseline and 6 and 12 weeks. We used linear mixed models to examine the association between change in PADP and change in NT-proBNP, adjusting for baseline covariates. Of 62 patients, the mean patient age was 66.2 years, and 63% were male. The mean baseline PADP was 21.8 ± 6.4 mm Hg, and the mean NT-proBNP was 1844.6 ± 2767.7 pg/mL. The mean change between baseline and averaged 6- and 12-week PADP was -0.4 ± 3.1 mm Hg, and the mean change between baseline and averaged 6- and 12-week NT-proBNP was -81.5 ± 878.6 pg/mL. In adjusted analyses, every 2-mm Hg decrease in PADP was associated with an NT-proBNP reduction of 108.9 pg/mL (95% confidence interval -4.3 to 222.0, P = .06). CONCLUSIONS: We observed that short-term decreases in ambulatory PADP seem to be associated with decreases in NT-proBNP. This finding may provide additional clinical context when tailoring treatment for patients with HF.

Rationale, Design and Baseline Characteristics of the PARAGLIDE-HF Trial: Sacubitril/Valsartan vs Valsartan in HFmrEF and HFpEF With a Worsening Heart Failure Event.

BACKGROUND: The PARAGON-HF trial studied the effect of sacubitril/valsartan (Sac/Val) compared with valsartan (Val) on clinical outcomes in patients with chronic heart failure with preserved ejection fraction (HFpEF) or mildly reduced EF (HFmrEF). Further data are needed regarding the use of Sac/Val in these groups with EF and with recent worsening heart failure (WHF) events and in key populations not broadly represented in the PARAGON-HF trial, including those with de novo HF, the severely obese and Black patients. METHODS: The PARAGLIDE-HF trial is a multicenter, double-blind, randomized, controlled trial of Sac/Val vs Val that enrolled patients at 100 sites. Medically stable patients ≥ 18 years old with EF > 40%, amino terminal-pro B-type natriuretic peptide (NT-proBNP) levels ≥ 500 pg/mL and within 30 days of a WHF event were eligible for participation. Patients were randomly assigned 1:1 to Sac/Val vs Val. The primary efficacy endpoint is time-averaged proportional change in NT-proBNP from baseline through Weeks 4 and 8. Secondary endpoints include clinical outcomes during follow-up and additional biomarker assessments. Safety endpoints include symptomatic hypotension, worsening renal function and hyperkalemia. RESULTS: The trial enrolled 467 participants from June 2019 through October 2022 (52% women, 22% Black, age 70 ± 12 years, median (IQR) BMI 33 (27-40) kg/m2). The median (IQR) EF was 55% (50%-60%), 23% with HFmrEF (LVEF 41%-49%), 24% with EF > 60% and 33% with de novo HFpEF. Median screening NT-proBNP was 2009 (1291-3813) pg/mL, and 69% were enrolled in the hospital. CONCLUSIONS: The PARAGLIDE-HF trial enrolled a broad and diverse range of patients with heart failure with mildly reduced or preserved ejection fraction and will inform clinical practice by providing evidence about the safety, tolerability and efficacy of Sac/Val vs Val in those with a recent WHF event.

Lack of durable natriuresis and objective decongestion following SGLT2 inhibition in randomized controlled trials of patients with heart failure.

Patients with heart failure have increased cardiac filling pressures, circulating natriuretic peptides, and physical signs of fluid retention, which are related to sodium retention by the kidneys and are alleviated by conventional diuretics. Sodium-glucose cotransporter 2 (SGLT2) inhibitors interfere with sodium and glucose reabsorption in the proximal renal tubule, but they evoke a marked counterregulatory activation of sodium and water reabsorption in distal nephron segments, which opposes and negates any diuretic effect. Nevertheless, it has been postulated that SGLT2 inhibitors modulate the volume set point, leading selectively to decongestion in patients with fluid overload. This hypothesis was tested in a review of 15 randomized controlled trials of SGLT2 inhibitors in patients with heart failure, with 7 trials focusing on urinary volume within the first week, and 8 trials focusing on objective decongestion at 12 weeks. In trials < 1 week, SGLT2 inhibition increased urine volume in the first 24 h, but typically without a change in urinary sodium excretion, and this diuresis was not sustained. In 8 trials of 12 weeks' duration, none reported alleviation of edema, ascites or pulmonary rales. The 2 trials that evaluated changes in left ventricular filling pressure noted no or small changes (1-2 mm Hg); the two trials that measured interstitial lung water or total blood volume found no effect; and 6 of the 7 trials found no decrease in circulating natriuretic peptides. Therefore, randomized controlled trials do not indicate that SGLT2 inhibitors produce a durable natriuresis or objective decongestion in patients with heart failure.

Genetic Dissection of a Super Enhancer Controlling the Nppa-Nppb Cluster in the Heart.

RATIONALE: ANP (atrial natriuretic peptide) and BNP (B-type natriuretic peptide), encoded by the clustered genes Nppa and Nppb, are important prognostic, diagnostic, and therapeutic proteins in cardiac disease. The spatiotemporal expression pattern and stress-induction of the Nppa and Nppb are tightly regulated, possibly involving their coregulation by an evolutionary conserved enhancer cluster. OBJECTIVE: To explore the physiological functions of the enhancer cluster and elucidate the genomic mechanism underlying Nppa-Nppb coregulation in vivo. METHODS AND RESULTS: By analyzing epigenetic data we uncovered an enhancer cluster with super enhancer characteristics upstream of Nppb. Using CRISPR/Cas9 genome editing, the enhancer cluster or parts thereof, Nppb and flanking regions or the entire genomic block spanning Nppa-Nppb, respectively, were deleted from the mouse genome. The impact on gene regulation and phenotype of the respective mouse lines was investigated by transcriptomic, epigenomic, and phenotypic analyses. The enhancer cluster was essential for prenatal and postnatal ventricular expression of Nppa and Nppb but not of any other gene. Enhancer cluster-deficient mice showed enlarged hearts before and after birth, similar to Nppa-Nppb compound knockout mice we generated. Analysis of the other deletion alleles indicated the enhancer cluster engages the promoters of Nppa and Nppb in a competitive rather than a cooperative mode, resulting in increased Nppa expression when Nppb and flanking sequences were deleted. The enhancer cluster maintained its active epigenetic state and selectivity when its target genes are absent. In enhancer cluster-deficient animals, Nppa was induced but remained low in the postmyocardial infarction border zone and in the hypertrophic ventricle, involving regulatory sequences proximal to Nppa. CONCLUSIONS: Coordinated ventricular expression of Nppa and Nppb is controlled in a competitive manner by a shared super enhancer, which is also required to augment stress-induced expression and to prevent premature hypertrophy.

Protective effect of sacubitril/valsartan (Entresto) on kidney function and filtration barrier injury in a porcine model of partial nephrectomy.

Kidney surgery often includes organ ischaemia with a risk of acute kidney injury. The present study tested if treatment with the combined angiotensin II-angiotensin II receptor type 1 and neprilysin blocker Entresto (LCZ696, sacubitril/valsartan) protects filtration barrier and kidney function after ischaemia and partial nephrectomy (PN) in pigs. Single kidney glomerular filtration rate (GFR) by technetium-99m diethylene-triamine-pentaacetate clearance was validated (n = 6). Next, four groups of pigs were followed for 15 days (n = 24) after PN (one-third right kidney, 60 min ischaemia) + Entresto (49/51 mg/day; n = 8), PN + vehicle (n = 8), sham + Entresto (49/51 mg/day; n = 4) and sham + vehicle (n = 4). GFR, diuresis and urinary albumin were measured at baseline and from each kidney after 15 days. The sum of single-kidney GFR (right 25 ± 6 mL/min, left 31 ± 7 mL/min) accounted for the total GFR (56 ± 14 mL/min). Entresto had no effect on baseline blood pressure, p-creatinine, mid-regional pro-atrial natriuretic peptide (MR-proANP), heart rate and diuresis. After 15 days, Entresto increased GFR in the uninjured kidney (+23 ± 6 mL/min, P < .05) and reduced albuminuria from both kidneys. In the sham group, plasma MR-proANP was not altered by Entresto; it increased to similar levels 2 h after surgery with and without Entresto. Fractional sodium excretion increased with Entresto. Kidney histology and kidney injury molecule-1 in cortex tissue were not different. In conclusion, Entresto protects the filtration barrier and increases the functional adaptive response of the uninjured kidney.

Prognostic Importance of B-Type Natriuretic Peptide Level in Patients Undergoing Catheter Ablation for Atrial Fibrillation.

BACKGROUND: This study assessed the prognostic importance of B-type natriuretic peptide (BNP) concentrations for clinical events after catheter ablation for atrial fibrillation (AF).Methods and Results: We enrolled 1,750 consecutive patients undergoing initial AF ablation whose baseline BNP data were available from a large-scale multicenter observational cohort (TRANQUILIZE-AF Registry). The prognostic impact of BNP concentration on clinical outcomes, including recurrent tachyarrhythmias and a composite of heart failure (HF) hospitalization or cardiac death, was evaluated. Median baseline BNP was 94.2 pg/mL. During a median follow-up of 2.4 years, low BNP (<38.3 pg/mL) was associated with lower rates of recurrent atrial tachyarrhythmias than BNP concentrations ≥38.3 pg/mL (19.9% vs. 30.6% at 3 years; P<0.001) and HF (0.8% vs. 5.3% at 3 years; P<0.001). Multivariable Cox regression analyses revealed that low BNP was independently associated with lower risks of arrhythmia recurrence (hazard ratio [HR] 0.63; 95% confidence interval [CI] 0.47-0.82; P<0.001) and HF (HR 0.17; 95% CI 0.04-0.71; P=0.002). The favorable impact of low BNP on arrhythmia recurrence was prominent in patients with paroxysmal, but not non-paroxysmal, AF, particularly among those with long-standing AF. CONCLUSIONS: Low BNP concentrations had a favorable impact on clinical outcomes after AF ablation. The heterogeneous impact of baseline BNP concentrations on arrhythmia recurrence for the subgroups of patients divided by AF type warrants future larger studies with longer follow-up periods.

Diagnostic utility of total NT-proBNP testing by immunoassay based on antibodies targeting glycosylation-free regions of NT-proBNP.

OBJECTIVES: The N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) is a widely used heart failure (HF) biomarker. Commercial NT-proBNP immunoassays detect only a subfraction of endogenous NT-proBNP, as the antibodies target a region of NT-proBNP that could be glycosylated at Ser44. The diagnostic utility of immunoassays measuring total NT-proBNP remains unclear. METHODS: NT-proBNP was measured in 183 HF and 200 non-HF patients diagnosed by two independent cardiologists blinded to NT-proBNP results. Plasma samples either non-treated or treated with a mixture of glycosidases were analyzed by the Elecsys proBNP II assay (Roche Diagnostics, based on antibodies targeting a glycosylated region of NT-proBNP) and the SuperFlex NT-proBNP assay (PerkinElmer, based on antibodies targeting regions of NT-proBNP that are free of O-glycans). The diagnostic accuracy of the two assays was analyzed by comparison of ROC curves. RESULTS: The ROC-AUC for the proBNP II assay was 0.943 (95% CI 0.922-0.964) for NT-proBNP measured in untreated samples and 0.935 (0.913-0.958) for NT-proBNP measured in glycosidase-treated samples. The SuperFlex NT-proBNP assay in untreated samples gave a ROC-AUC of 0.930 (95% CI 0.907-0.954). The median percentage of non-glycosylated NT-proBNP to total NT-proBNP was 1.5-1.6-fold lower in the non-HF group compared to that in the HF group. CONCLUSIONS: The clinical value of total NT-proBNP for HF diagnosis was similar to the subfraction of NT-proBNP that was non-glycosylated at Ser44. The lower percentage of non-glycosylated NT-proBNP to total NT-proBNP in non-HF patients suggests that total NT-proBNP might be more sensitive in individuals without current or prior symptoms of HF.