Effects of sacubitril/valsartan on neprilysin targets and the metabolism of natriuretic peptides in chronic heart failure: a mechanistic clinical study

Angiotensin receptor-neprilysin inhibitors: Comprehensive review and implications in hypertension treatment

Angiotensin receptor-neprilysin inhibitors (ARNIs) are a new class of cardiovascular agents characterized by their dual action on the major regulators of the cardiovascular system, including the renin-angiotensin system (RAS) and the natriuretic peptide (NP) system. The apparent clinical benefit of one ARNI, sacubitril/valsartan, as shown in clinical trials, has positioned the drug class as a first-line therapy in patients with heart failure, particularly with reduced ejection fraction. Accumulating evidence also suggests that sacubitril/valsartan is superior to conventional RAS blockers in lowering blood pressure in patients with hypertension. To decide whether to apply an ARNI to treat hypertension clinically, it is important to understand the potential properties of the drug in modulating multiple factors inside and outside the cardiovascular system beyond its effect on reducing peripheral blood pressure. In this context, ARNIs are distinct from preexisting antihypertensive medications in terms of the multiple actions of NPs in various organs and the pharmacological potential of neprilysin inhibitors to modulate multiple cardiac and noncardiac peptides. In particular, analysis of the clinical trials of sacubitril/valsartan implies that ARNIs can provide additional clinical benefits independent of their original purpose, including alleviation of glycemic control and renal impairment in patients with heart failure. Understanding the potential mechanisms of action of ARNIs will help interpret the relevance of their additional benefits beyond lowering blood pressure in hypertension. This review summarizes the comprehensive clinical evidence and relevance of ARNIs by specifically focusing on the potential properties of this new drug class in treating patients with hypertension.

Low- vs high-dose ARNI effects on clinical status, exercise performance and cardiac function in real-life HFrEF patients

Purpose

Only a few studies are available on dose-related effects of sacubitril/valsartan (angiotensin receptor neprilysin inhibition (ARNI)) in real-life patients with heart failure and reduced ejection fraction (HFrEF). We sought to investigate clinical and functional effects in real-life HFrEF patients receiving ARNI at a different cumulative dose.

Methods

This was an observational study in consecutive outpatients admitted for HFrEF from October 2017 to June 2019. The PARADIGM criteria were needed for enrolment. ARNI was uptitrated according to blood pressure, drug tolerability, renal function and kaliemia. At least 10-month follow-up was required in each patient. Clinical assessment, Kansas City Cardiomyopathy Questionnaire (KCCQ) score, 6-min walk test and strain echocardiography were performed in each patient on a regular basis during the observational period. At the end of the study, patients were divided into two groups based on the median yearly dose of the ARNI medication.

Results

A total of 90 patients, 64 ± 11 years, 82% males, were enrolled. The cut-off dose was established in 75 mg BID, and the study population was divided into group A (≤ 75 mg), 52 patients (58%), and group B (> 75 mg), 38 patients (42%). The follow-up duration was 12 months (range 11–13). NYHA class, KCCQ score and 6MWT performance ameliorated in both groups, with a quicker time to benefit in group B. The proportion of patients walking > 350 m increased from 21 to 58% in group A (p < 0.001), and from 29 to 82% in group B (p < 0.001). A positive effect was also disclosed in the left ventricular remodelling, strain deformation and diastolic function.

Conclusion

One-year ARNI treatment was effective in our real-life HFrEF patient population, leading to clinical and functional improvement in both study groups, slightly greater and with a shorter time to benefit in group B.

Supplementary information

The online version contains supplementary material available at 10.1007/s00228-021-03210-0.

Disease-modifier Drugs in Patients with Advanced Heart Failure: How to Optimize Their Use?

Therapy based on disease-modifier drugs is among the required criteria to diagnose advanced heart failure (AdvHF). Nevertheless, several conditions, such as hospitalization, hypotension, renal dysfunction, electrolyte abnormalities, medical inertia, and patients' adherence, can make the maintenance of optimal medical therapy in patients with AdvHF challenging. Moreover, in recent years, new classes of drugs able have been shown to be able to further modify the natural history of heart failure with reduced ejection fraction, but they are still not widely adopted. This article discusses the optimal use of disease-modifier drugs in patients with AdvHF as well as the possible usefulness of the new therapeutic opportunities.

Ability of soluble ST2 to predict left ventricular remodeling in patients with acute coronary syndrome

The association of the soluble suppression of tumorigenicity 2 (sST2) and the prognosis of heart failure have been well evaluated. However, little is known about the prediction of sST2 for left ventricular (LV) remodeling in acute coronary syndrome (ACS). We investigated the ability of sST2 to predict LV remodeling following the revascularization of ACS. From May 2019 to December 2020, 95 patients with LV ejection fraction (EF) < 50% who underwent coronary revascularization for ACS (unstable angina, non-ST-elevation myocardial infarction, ST-elevation myocardial infarction) were enrolled. Echocardiography and sST2 were performed at baseline and at a 3-month follow-up. The association between LV remodeling, using the end-diastolic volume index, and sST2 at baseline and at the 3-month follow-up, and the difference between each value was explored. During follow-up, 41 patients showed LV adverse remodeling. The baseline sST2 increased in patients without adverse remodeling (32.05 ng/mL vs. 23.5 ng/mL, p < 0.001), although clinical characteristics were similar between the two groups. During the mean follow-up of 3 months, a significant correlation was found in the changes between sST2 and LV end-diastolic/systolic volume index (r = 0.649; p < 0.001, r = 0.618; p < 0.001, respectively), but not in the changes of LVEF (r = - 0.132, p = 0.204). The use of angiotensin-converting enzyme 2 inhibitors/receptor blockers was higher (90.7% vs. 53.7%, p < 0.001) and sST2 decreased more predominantly in patients without adverse remodeling (23.18 ng/mL vs 26.40 ng/mL, p = 0.003). However, the changes in sST2 and LV volume were not different according to the ACS types (p > 0.05, for all). Estimates of the odds ratio (OR) for remodeling according to the sST2 difference increased substantially with a negative increase in the sST2 difference. Multivariable analysis found that, the difference between the baseline and 3-month sST2 was the most important determinant of LV remodeling following the revascularization of ACS (OR 1.24; 95% confidence interval: 1.09 to 1.41; p = 0.001). In conclusion, an increase in sST2 during follow-up was a useful predictor of LV remodeling.

Active B-Type Natriuretic Peptide Measured by Mass Spectrometry and Response to Sacubitril/Valsartan

BACKGROUND

B-type natriuretic peptide (BNP) immunoassays (BNP_ia) do not differentiate active and inactive forms. Inactive NT-proBNP is used to track heart failure (HF) during treatment with sacubitril/valsartan, which inhibits BNP degradation. Mass spectrometry (MS) may better assess effects of HF treatment on biologically active BNP1-32.

METHODS AND RESULTS

We developed a MS assay with immediate protease inhibition to quantify BNP1-32 over a linear range, using labeled recombinant BNP standard. In 4 healthy volunteers, BNP1-32 by MS (BNP_MS) increased from below the 5 pg/mL detection limit to 228 pg/mL after nesiritide. In patients with HF, BNP_MS was measured in parallel with BNP and NT-proBNP immunoassays before and during sacubitril/valsartan treatment. BNP_MS was 4.4-fold lower than BNP_ia in patients with HF. Among patients not taking sacubitril/valsartan and without end-stage renal disease, BNP_MS correlated with BNP_ia (r_s = 0.77, P < .001) and NT-proBNP (r_s = 0.74, P < .001). After a median of 8 weeks on sacubitril/valsartan, active BNP_MS levels decreased by 50% (interquartile range -98.3% to 41.7%, n = 22, P = .048) and correlated with NT-proBNP (r_s = 0.64, P < .001), but not with BNP_ia (r_s = 0.46, P = .057).

CONCLUSIONS

Active BNP measured by MS accounts for only a small amount of BNP measured by immunoassays. Although decreased BNP production was anticipated to be masked by inhibition of degradation, levels of active BNP decreased during chronic sacubitril/valsartan treatment.

Effect of Sacubitril/Valsartan on circulating catecholamine levels during a 6-month follow-up in heart failure patients. Timeo Danaos et dona ferentes?

We assessed the effect of Sacubitril/Valsartan on circulating catecholamine levels in patients with HF in an observational cohort study. We included 108 consecutive HF patients attending our HF Outpatients Clinic who were eligible to Sacubitril/Valsartan according to the PARADIGM-HF inclusion and exclusion criteria. We furthermore included 58 stable HF patients under optimal medical therapy as a control group. Norepinephrine and epinephrine were measured with immunoradiometric assays at baseline, at 3- and at 6-month time follow-up. Compared to baseline levels there was no change at three months in epinephrine (p = 0.177) or norepinephrine (p = 0.815) concentrations. At 6 months norepinephrine remained unchanged (p = 0.359). However, at 6 months we observed a significant increase in epinephrine levels compared to baseline [66 pg/mL (37-93) vs 38 pg/mL (18-74), p < 0.001]. In the control group no change was observed in epinephrine levels compared to baseline (p = 0.838). This study is the first to report on the effect of the new drug Sacubitril/Valsartan on circulating catecholamine levels in HF patients. Our data show a significant increase in epinephrine levels during a 6 month follow up in stable HF patients.

Neprilysin Inhibition Increases Glucagon Levels in Humans and Mice With Potential Effects on Amino Acid Metabolism

Context

Inhibitors of the protease neprilysin (NEP) are used for treating heart failure, but are also linked to improvements in metabolism. NEP may cleave proglucagon-derived peptides, including the glucose and amino acid (AA)-regulating hormone glucagon. Studies investigating NEP inhibition on glucagon metabolism are warranted.

Objective

This work aims to investigate whether NEP inhibition increases glucagon levels.

Methods

Plasma concentrations of glucagon and AAs were measured in eight healthy men during a mixed meal with and without a single dose of the NEP inhibitor/angiotensin II type 1 receptor antagonist, sacubitril/valsartan (194 mg/206 mg). Long-term effects of sacubitril/valsartan (8 weeks) were investigated in individuals with obesity (n = 7). Mass spectrometry was used to investigate NEP-induced glucagon degradation, and the derived glucagon fragments were tested pharmacologically in cells transfected with the glucagon receptor (GCGR). Genetic deletion or pharmacological inhibition of NEP with or without concomitant GCGR antagonism was tested in mice to evaluate effects on AA metabolism.

Results

In healthy men, a single dose of sacubitril/valsartan significantly increased postprandial concentrations of glucagon by 228%, concomitantly lowering concentrations of AAs including glucagonotropic AAs. Eight-week sacubitril/valsartan treatment increased fasting glucagon concentrations in individuals with obesity. NEP cleaved glucagon into 5 inactive fragments (in vitro). Pharmacological NEP inhibition protected both exogenous and endogenous glucagon in mice after an AA challenge, while NEP-deficient mice showed elevated fasting and AA-stimulated plasma concentrations of glucagon and urea compared to controls.

Conclusion

NEP cleaves glucagon, and inhibitors of NEP result in hyperglucagonemia and may increase postprandial AA catabolism without affecting glycemia.

A Low-Sodium Diet Boosts Ang (1-7) Production and NO-cGMP Bioavailability to Reduce Edema and Enhance Survival in Experimental Heart Failure

Sodium restriction is often recommended in heart failure (HF) to block symptomatic edema, despite limited evidence for benefit. However, a low-sodium diet (LSD) activates the classical renin-angiotensin-aldosterone system (RAAS), which may adversely affect HF progression and mortality in patients with dilated cardiomyopathy (DCM). We performed a randomized, blinded pre-clinical trial to compare the effects of a normal (human-equivalent) sodium diet and a LSD on HF progression in a normotensive model of DCM in mice that has translational relevance to human HF. The LSD reduced HF progression by suppressing the development of pleural effusions (p < 0.01), blocking pathological increases in systemic extracellular water (p < 0.001) and prolonging median survival (15%, p < 0.01). The LSD activated the classical RAAS by increasing plasma renin activity, angiotensin II and aldosterone levels. However, the LSD also significantly up-elevated the counter-regulatory RAAS by boosting plasma angiotensin converting enzyme 2 (ACE2) and angiotensin (1-7) levels, promoting nitric oxide bioavailability and stimulating 3'-5'-cyclic guanosine monophosphate (cGMP) production. Plasma HF biomarkers associated with poor outcomes, such as B-type natriuretic peptide and neprilysin were decreased by a LSD. Cardiac systolic function, blood pressure and renal function were not affected. Although a LSD activates the classical RAAS system, we conclude that the LSD delayed HF progression and mortality in experimental DCM, in part through protective stimulation of the counter-regulatory RAAS to increase plasma ACE2 and angiotensin (1-7) levels, nitric oxide bioavailability and cGMP production.

Protection of kidney function and tissue integrity by pharmacologic use of natriuretic peptides and neprilysin inhibitors

With variable potencies atrial-, brain-type and c-type natriuretic peptides (NP)s, best documented for ANP and its analogues, promote sodium and water excretion, renal blood flow, lipolysis, lower blood pressure, and suppress renin and aldosterone secretion through interaction predominantly with cGMP-coupled NPR-A receptor. Infusion of especially ANP and its analogues up to 50 ng/kg/min in patients with high risk of acute kidney injury (cardiac vascular bypass surgery, intraabdominal surgery, direct kidney surgery) protects kidney function (GFR, plasma flow, medullary flow, albuminuria, renal replacement therapy, tissue injury) at short term and also long term and likely additively with the diuretic furosemide. This documents a pharmacologic potential for the pathway. Neprilysin (NEP, neutral endopeptidase) degrades NPs, in particular ANP, and angiotensin II. The drug LCZ696, a mixture of the neprilysin inhibitor sacubitril and the ANGII-AT1 receptor blocker valsartan, was FDA approved in 2015 and marketed as Entresto®. In preclinical studies of kidney injury, LCZ696 and NPs lowered plasma creatinine, countered hypoxia and oxidative stress, suppressed proinflammatory cytokines, and inhibited fibrosis. Few randomized clinical studies exist and were designed with primary cardiac outcomes. The studies showed that LCZ696/entresto stabilized and improved glomerular filtration rate in patients with chronic kidney disease. LCZ696 is safe to use concerning kidney function and stabilizes or increases GFR. In perspective, combined AT1 and neprilysin inhibition is a promising approach for long-term renal protection in addition to AT1 receptor blockers in acute kidney injury and chronic kidney disease.

Effects of Angiotensin Receptor-Neprilysin Inhibitor in Arrhythmogenicity Following Left Atrial Appendage Closure in an Animal Model

PURPOSE

Left atrial appendage (LAA) closure decreases atrial natriuretic peptide (ANP) levels, which indirectly increases the risk of arrhythmogenicity. We aimed to determine the effect of a combined angiotensin receptor-neprilysin inhibitor (ARNi) on arrhythmogenicity following LAA closure in an animal model.

METHODS

Twenty-four rabbits were randomized into four groups: (1) control, (2) LAA closure (LAAC), (3) heart failure (HF)-LAAC, and (4) HF-LAAC with sacubitril/valsartan (+ARNi). HF models were developed in the HF-LAAC and HF-LAAC+ARNi groups. Epicardial LAA exclusion was performed in the LAAC, HF-LAAC, and HF-LAAC+ARNi groups. ANP levels were measured. An electrophysiological study was performed. The myocardium was harvested for histopathological analysis.

RESULTS

The ANP level decreased in the LAAC group (785 ± 103 pg/mL, p = 0.03), failed to increase in the HF-LAAC group (917 ± 172 pg/mL, p = 0.3), and increased in the HF-LAAC+ARNi group (1524 ± 126 pg/mL, p < 0.01) compared to that in the control group (1014 ± 56 pg/mL). The atrial effective refractory period (ERP) was prolonged in the HF-LAAC group and restored to baseline in the HF-LAAC+ARNi group. Ventricular ERP was the longest in the HF-LAAC group. The atrial fibrillation window of vulnerability (AF WOV) was elevated in the LAAC, HF-LAAC, and HF-LAAC+ARNi groups, with the latter group having lower AF WOV than the two former groups. Ventricular fibrillation (VF) inducibility was the highest in the HF-LAAC group (51 ± 5%, p < 0.001), followed by the LAAC group (30 ± 4%, p = 0.006) and the HF-LAAC+ARNi group (25 ± 5%, p = 0.11) when compared to the control group (18 ± 4%). Atrial and ventricular fibrosis were noted in all groups except the control group.

CONCLUSION

LAA closure decreased ANP, which in turn increased AF and VF inducibility. Atrial and ventricular arrhythmogenicity was suppressed by ARNi.

Angiotensin Receptor-Neprilysin Inhibitors and the Natriuretic Peptide Axis

PURPOSE OF THE REVIEW

The purpose of this review is to describe the effects of angiotensin receptor neprilysin inhibitor (ARNI) therapy on the natriuretic peptide axis (NPA), with a particular focus on B-type natriuretic peptide (BNP), atrial natriuretic peptide (ANP), and C-type natriuretic peptide (CNP) to better understand the biology behind the improved outcomes in patients with heart failure with reduced ejection fraction (HFrEF).

RECENT FINDINGS

BNP, ANP, and CNP are the three main natriuretic peptides (NP); they share a common structure and ultimately mediate their actions by activating cyclic guanosine monophosphate (cGMP). ARNI therapy results in a decrease of N-terminal pro-BNP (NT-proBNP) and increase of BNP levels respectively. It is been questioned whether these changes may result from unique laboratory assays characteristics rather than actual biological implications. It appears to be that the prognostic accuracy of BNP for cardiovascular outcomes remains independent and comparable to that of NT-proBNP while on ARNI therapy. ANP levels also increase with ARNI therapy, but no consistent change has been described for CNP levels. There is evidence that the changes in BNP and NT-proBNP correlate with improvement in echocardiographic parameters of volume and function. The dual effect of neprilysin inhibition and angiotensin receptor blockade has substantial implications on the natriuretic peptide axis (NPA). The changes seen in BNP and NT-proBNP specifically have shown to correlate with improvement in echocardiographic parameters. Further results exploring the biologic effects of ARNI therapy on other NPs are still pending and likely will provide further insights in the mechanisms behind the improvement in cardiac function and clinical outcomes.

Neprilysin inhibition does not alter dynamic of proenkephalin-A 119-159 and pro-substance P in heart failure

AIMS

As NEP degrades many substrates, the specific therapeutic mechanism of NEP inhibition with angiotensin receptor neprilysin inhibitor (ARNi) in heart failure with reduced ejection fraction (HFrEF) is not entirely evident. The aim of this study was to investigate the response of two substrates of NEP-the tachykinin and enkephalin systems-to the initiation of ARNi therapy in HFrEF.

METHODS AND RESULTS

Between 2016 and 2018, 141 consecutive patients with stable HFrEF [74 with initiation of ARNi and 67 controls on continuous angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) therapy] were prospectively enrolled. Plasma proenkephalin-A 119-159 (PENK) and pro-substance P (pro-SP) were serially determined. Proenkephalin-A 119-159 and pro-SP correlated strongly with each other (r_s  = 0.67, P < 0.001) and kidney function (r_s  = -0.66, P < 0.001 and r_s  = -0.54, P < 0.001) and modestly with NT-proBNP (r_s  = 0.32, P < 0.001 and r_s  = 0.24, P = 0.006, respectively). Concentrations of circulating PENK were slightly elevated after 1 and 2 year follow-up compared with baseline (BL) [BL median: 67.4 pmol/L (IQR: 57.3-89.8), 1 year: 83.5 pmol/L (IQR: 62.4-111.6), 2 years: 92.3 pmol/L (IQR: 63.1-101.9); BL vs. 1 year: P = 0.017 and BL vs. 2 years: P = 0.019] in the overall analysis, but lost significance at 2 year follow-up when assessed in paired subanalysis (P = 0.116). Plasma pro-SP levels remained comparable during the entire follow-up [BL median: 78.3 pmol/L (IQR: 67.9-90.6), 1 year: 75.9 pmol/L (IQR: 58.6-96.3), 2 years: 79.7 pmol/L (IQR: 59.9-105.3); P = ns for both timepoints]. Biomarker patterns of ARNi patients were independent from baseline therapy, that is, ACEi or ARB (P > 0.05 between groups).

CONCLUSIONS

Although enkephalins and SP are known substrates of NEP, NEP inhibition by ARNi does not clearly affect the circulating precursors PENK and pro-SP in HFrEF.

Sacubitril-valsartan treatment is associated with decrease in central apneas in patients with heart failure with reduced ejection fraction

BACKGROUND

To assess the impact of sacubitril-valsartan on apneic burden in patients with heart failure with reduced ejection fraction (HFrEF), 51 stable HFrEF patients planned for switching from an ACE-i/ARB to sacubitril-valsartan were prospectively enrolled.

METHODS AND RESULTS

At baseline and after 6 months of treatment, all patients underwent echocardiography, 24-h cardiorespiratory monitoring, neurohormonal evaluation, and cardiopulmonary exercise testing. At baseline 29% and 65% of patients presented with obstructive and central apneas, respectively. After 6 months, sacubitril-valsartan was associated with a decrease in NT-proBNP, improvement in LV function, functional capacity and ventilatory efficiency. After treatment, the apnea-hypopnea index (AHI) decreased across the 24-h period (p < 0.001), as well as at daytime (p < 0.001) and at nighttime (p = 0.026), proportionally to baseline severity. When subgrouping according to the type of apneas, daytime, nighttime and 24-h AHI decreased in patients with central apneas (all p < 0.01). Conversely, in patients with obstructive apneas, the effect of drug administration was neutral at nighttime, with significant decrease only in daytime events (p = 0.007), mainly driven by reduction in hypopneas.

CONCLUSIONS

Sacubitril-valsartan on top of medical treatment is associated with a reduction in the apneic burden among a real-life cohort of HFrEF patients. The most marked reduction was observed for central apneas.

Sacubitril/valsartan ameliorates cardiac hypertrophy and preserves diastolic function in cardiac pressure overload

Aims

Sacubitril/valsartan (sac/val) has shown superior effect compared with blockade of the renin–angiotensin–aldosterone system in heart failure with reduced ejection fraction. We aimed to investigate effects of sac/val compared with valsartan in a pressure overload model of heart failure with preserved ejection fraction (HFpEF).

Methods and results

Sprague–Dawley rats underwent aortic banding or sham (n = 16) surgery and were randomized to sac/val (n = 28), valsartan (n = 29), or vehicle (n = 26) treatment for 8 weeks. Sac/val reduced left ventricular weight by 11% compared with vehicle (P = 0.01) and 9% compared with valsartan alone (P = 0.04). Only valsartan reduced blood pressure compared with sham (P = 0.02). Longitudinal early diastolic strain rate was preserved in sac/val compared with sham, while it was reduced by 23% in vehicle (P = 0.03) and 24% in valsartan (P = 0.02). Diastolic dysfunction, measured by E/e'SR, increased by 68% in vehicle (P < 0.01) and 80% in valsartan alone (P < 0.001), while sac/val showed no increase. Neither sac/val nor valsartan prevented interstitial fibrosis. Although ejection fraction was preserved, we observed mild systolic dysfunction, with vehicle showing a 28% decrease in longitudinal strain (P < 0.01). Neither sac/val nor valsartan treatment improved this dysfunction.

Conclusions

In a model of HFpEF induced by cardiac pressure overload, sac/val reduced hypertrophy compared with valsartan alone and ameliorated diastolic dysfunction. These effects were independent of blood pressure. Early systolic dysfunction was not affected, supporting the notion that sac/val has the largest potential in conditions characterized by reduced ejection fraction. Observed anti‐hypertrophic effects in preserved ejection fraction implicate potential benefit of sac/val in the clinical setting of hypertrophic remodelling and impaired diastolic function.

Effects of Sacubitril/Valsartan in Patients with High Arrhythmic Risk and an ICD: A Longitudinal Study

PURPOSE

Patients affected by heart failure with reduced ejection fraction (HFrEF) receive clinical and functional beneficial effects from treatment with sacubitril/valsartan. However previous studies have shown that patients with an implantable cardioverter defibrillator (ICD) could obtain even greater benefit, but only make up a only a small proportion of patients. In the current study we evaluated the effect of sacubitril/valsartan in patients with an ICD.

METHODS

Thirty-five outpatients with HFrEF (aged 60 ± 11 years, 28 were males), on optimal medical therapy were studied. All patients received an ICD at least 6 months before enrollment or were non-responders to ICD plus resynchronization (CRT-D). An open-label sacubitril/valsartan treatment was established at the maximum tolerated dose. Clinical assessment, 6-min walk test (6MWT) and echocardiography, were performed during follow-up at 90, 180, and 360 days. Quality of life score and perceived fatigue on exercise were assessed.

RESULTS

Clinical conditions dramatically improved in most patients, especially within the first 6 months of therapy (76 % were in NYHA-I and 24 % in NYHA-II at the end of study vs 71 % NYHA-II and 29 % NYHA III at enrollment, p < 0.001). Quality of life and exercise performance significantly improved according to N-terminal pro-brain natriuretic peptide (NT-proBNP) serum levels lowering. Walking distance at 6MWT increased from 274 ± 97 to 389 ± 53 m and walking speed from 0.74 ± 0.27 to 1.07 ± 0.15 m/s (p < 0.001), while oxygen saturation did not differ significantly (from 90 ± 1 % to 91 ± 2 %). More gradual was left ventricular reverse remodeling. Ejection fraction improved mildly (+ 5 points %, p < 0.001). Global longitudinal strain and diastolic function were also assessed over time.

CONCLUSION

Sacubitril/valsartan therapy for HFrEF may lead to significant clinical and functional improvements even in patients with ICD at greater arrhythmic risk. Clinical improvement is obtained within the first 6 months of treatment while reverse remodeling needs more time.

Angiotensin Receptor Neprilysin Inhibitors in HFrEF: Is This the First Disease Modifying Therapy Drug Class Leading to a Substantial Reduction in Diuretic Need?

Despite significant advances in disease modifying therapy in heart failure (HF), diuretics have remained the cornerstone of volume management in all HF phenotypes. Diuretics, alongside their definite acute haemodynamic and symptomatic benefits, also possess many possible deleterious side effects. Moreover, questions remain regarding the prognostic impact of chronic diuretic use. To date, few data exist pertaining to diuretic reduction as a result of individual traditional guideline directed medical therapy in HF with reduced ejection fraction (HFrEF). However, diuretic reduction has been demonstrated with sacubitril/valsartan (angiotensin receptor-neprilysin inhibitor [ARNi]) from the PARADIGM study, as well as, post-marketing reports from our own group and others. Whether the ARNi compound represents the dawn of a new era, where effective therapies will have a more noticeable reduction on diuretic need, remains to be seen. The emergence of sodium glucose transport 2 inhibitors and guanylate cyclase stimulators may further exemplify this issue and potentially extend this benefit to HF patients outside of the HFrEF phenotype. In conclusion, emerging new therapies in HFrEF could reduce the reliance on diuretics in the management of this phenotype of HF. These developments further highlight the clinical importance to continually assess an individual's diuretic requirements through careful volume assessment.

Heart failure in the last year: progress and perspective

Research about heart failure (HF) has made major progress in the last years. We give here an update on the most recent findings. Landmark trials have established new treatments for HF with reduced ejection fraction. Sacubitril/valsartan was superior to enalapril in PARADIGM‐HF trial, and its initiation during hospitalization for acute HF or early after discharge can now be considered. More recently, new therapeutic pathways have been developed. In the DAPA‐HF and EMPEROR‐Reduced trials, dapagliflozin and empagliflozin reduced the risk of the primary composite endpoint, compared with placebo [hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.65–0.85; P < 0.001 and HR 0.75; 95% CI 0.65–0.86; P < 0.001, respectively]. Second, vericiguat, an oral soluble guanylate cyclase stimulator, reduced the composite endpoint of cardiovascular death or HF hospitalization vs. placebo (HR 0.90; 95% CI 0.82–0.98; P = 0.02). On the other hand, both the diagnosis and treatment of HF with preserved ejection fraction, as well as management of advanced HF and acute HF, remain challenging. A better phenotyping of patients with HF would be helpful for prognostic stratification and treatment selection. Further aspects, such as the use of devices, treatment of arrhythmias, and percutaneous treatment of valvular heart disease in patients with HF, are also discussed and reviewed in this article.

How Diabetes and Heart Failure Modulate Each Other and Condition Management

Heart failure (HF) and diabetes mellitus (DM) confer considerable burden on the health care system. Although these often occur together, DM can increase risk of HF, whereas HF can accelerate complications of DM. HF is a clinical syndrome resulting from systolic or diastolic impairment caused by ischemic, nonischemic (eg, DM), or other etiologies. HF exists along a spectrum from stage A (ie, persons at risk of DM) to stage D (ie, refractory HF from end-stage DM cardiomyopathy [DMCM]). HF is further categorized by reduced, midrange, and preserved ejection fraction (EF). In type 2 DM, the most prevalent form of DM, several pathophysiological mechanisms (eg, insulin resistance and hyperglycemia) can contribute to myocardial damage, leading to DMCM. Management of HF and DM and patient outcomes are guided by EF and drug efficacy. In this review, we focus on the interplay between HF and DM on disease pathophysiology, management, and patient outcomes. Specifically, we highlight the role of novel antihyperglycemic (eg, sodium glucose cotransporter 2 inhibitors) and HF therapies (eg, renin-angiotensin-aldosterone system inhibitors) on HF outcomes in patients with DM and HF.

Atrial Natriuretic Peptide and Treatment With Sacubitril/Valsartan in Heart Failure With Reduced Ejection Fraction

OBJECTIVES

This study sought to assess associations between longitudinal change in atrial natriuretic peptide (ANP) and reverse cardiac remodeling following initiation of sacubitril/valsartan in patients with heart failure with reduced ejection fraction (HFrEF).

BACKGROUND

Neprilysin inhibition results in an increase of several vasoactive peptides that may mediate the beneficial effects of sacubitril/valsartan, including ANP.

METHODS

In a prospective study of initiation and titration of sacubitril/valsartan in patients with HFrEF, blood was collected at scheduled time points into tubes containing protease inhibitors. This pre-specified exploratory analysis included patients in whom ANP was measured at baseline and serially through 12 months of treatment.

RESULTS

Among 144 participants (mean age: 64.5 years; left ventricular ejection fraction: 30.8%), following initiation of sacubitril/valsartan, there was an early and significant increase in ANP, with the majority of rise from 99 pg/ml at baseline to 156 pg/ml at day 14 (p < 0.001). There was a further trend toward a second increase from day 30 to day 45 (p = 0.07). At maximal rise, ANP had doubled. In longitudinal analyses, early rise in ANP was followed by a subsequent increase in urinary cycle guanosine monophosphate. Larger early increase in ANP was associated with larger later improvements in left ventricular ejection fraction and left atrial volume index (p < 0.001 for both).

CONCLUSIONS

Concentrations of ANP doubled after initiation of sacubitril/valsartan in patients with HFrEF. Larger early increases in ANP were associated with a greater magnitude of subsequent reverse cardiac remodeling. (Effects of Sacubitril/Valsartan Therapy on Biomarkers, Myocardial Remodeling and Outcomes [PROVE-HF]; NCT02887183).

Neprilysin as a Biomarker: Challenges and Opportunities

Neprilysin (NEP) inhibition is a successful novel therapeutic approach in heart failure with reduced ejection fraction. Assessing individual NEP status might be important for gathering insights into mechanisms of disease and optimising individualised patient care. NEP is a zinc-dependent multisubstrate-metabolising oligoendopeptidase localised in the plasma membrane with the catalytic site facing the extracellular space. Although NEP activity in vivo is predominantly tissue-based, NEP can be released into the circulation via ectodomain shedding and exosomes. Attempts to determine circulating NEP concentrations and activity have not yet resulted in convincingly coherent results relating NEP biomarkers to heart failure disease severity or outcomes. NEP is naturally expressed on neutrophils, opening up the possibility of measuring a membrane-associated form with integrity. Small studies have linked NEP expression on neutrophils with inflammatory state and initial data might indicate its role in heart failure with reduced ejection fraction. Future studies need to assess the regulation of systemic NEP activity, which is assumed to be tissue-based, and the relationship of NEP activation with disease state. The relationship between tissue NEP activity and easily accessible circulating NEP biomarkers and the impact of the latter remains to be established.

BNP and NT-proBNP Interpretation in the Neprilysin Inhibitor Era

PURPOSE OF REVIEW

Describe the mechanisms that may influence change in measured natriuretic peptide levels when using the neprilysin inhibitor sacubitril to treat a patient with heart failure.

RECENT FINDINGS

Prior to the introduction of the neprilysin inhibitor sacubitril as part of a chemical combination with the angiotensin receptor blocker valsartan shown to reduce mortality and heart failure hospitalizations in patients with heart failure with reduced ejection fraction, the natriuretic peptide assays for B-type natriuretic peptide (BNP) and the amino-terminal proBNP (NT-proBNP) assays were shown to have similar diagnostic accuracy to differentiate heart failure from other etiologies of shortness of breath. Sacubitril/valsartan use has been shown to result in a modest and chronic elevation of BNP while reducing levels of NT-prBNP. This review explores the potential impact of these findings on interpreting natriuretic peptide results for diagnosis and prognosis, as well as explore the challenges associated with the heterogeneity of this finding, highlighting the impact of inhibiting neprilysin, a non-specific endopeptidase with multiple target sites within BNP and other proteins. With increased uptake of sacubitril/valsartan expected in patients with heart failure, interpretation of natriuretic peptide assays becomes somewhat more complex, particularly for BNP. However, knowing a baseline steady-state concentration and using the same assay can assist with BNP interpretation for diagnosis and prognosis.

An Impaired Natriuretic Peptide Hormone System May Play a Role in COVID-19 Severity in Vulnerable Populations

Advanced age, underlying cardiovascular disease (including hypertension), and obesity are associated with a higher risk of progression to severe hypoxemia, acute respiratory distress syndrome (ARDS), and death in COVID‐19‐infected patients. African Americans have a higher degree of COVID‐19 mortality. The incidence of salt‐sensitive hypertension is higher in older individuals and African Americans. Lower circulating levels of natriuretic peptides, key regulators of vascular tone and kidney function, have been associated with salt‐sensitive hypertension and obesity. Evidence has accumulated that ANP administered to pulmonary endothelial cells, isolated lungs, and patients suffering from ARDS reduces endothelial damage and preserves the endothelial barrier, thereby reducing pulmonary edema and inflammation. Epidemiologic and pharmacologic data suggest that deficiencies in the natriuretic peptide hormone system may contribute to the development of severe lung pathology in COVID‐19 patients, and treatments that augment natriuretic peptide signaling may have potential to limit progression to ARDS.

Increased concentrations of bioactive adrenomedullin subsequently to angiotensin-receptor/neprilysin-inhibitor treatment in chronic systolic heart failure

AIMS

The clinically investigated rationale for neprilysin (NEP)-inhibition by angiotensinreceptor-NEPinhibitor (ARNi) therapy is to induce elevations in endogenous natriuretic peptides. NEP, however, cleaves a broad spectrum of substrates, which partially hold significant implications in heart failure with reduced ejection fraction (HFrEF). The effect of NEP inhibition on these peptides has not been investigated thoroughly. This study explored the response of adrenomedullin (ADM) regulation to the initiation of ARNi.

METHODS

Seventy-four patients with stable HFrEF and initiation of ARNi were prospectively enrolled, 67 patients on continuous angiotensin-converting-enzyme inhibitor(ACEi)/angiotensin-receptor blocker (ARB) therapy served as control. Plasma bioactive-ADM (bio-ADM), mid-regional-pro-ADM (MR-proADM), B-typenatriuretic peptide (BNP) and N-terminal-pro-BNP (NT-proBNP) were determined at baseline, short-term, 1-year and 2-year follow up.

RESULTS

Following ARNi initiation both bio-ADM and MR-proADM concentrations were significantly increased at early and long-term follow up (bio-ADM [pg/mL]: 26.0 [interquartile range {IQR}: 17.7-37.5] vs. 50.8 [IQR: 36.5-78.1] vs. 54.6 [IQR: 42.0-97.1] vs. 57.4 [IQR: 48.5-161.6]; MR-proADM [nmol/L]: 0.87 [IQR: 0.64-1.12] vs. 1.25 [IQR: 0.93-1.79] vs. 1.42 [IQR: 0.95-1.90] vs. 1.60 [IQR: 1.12-2.46], P < .0001 for all). The ratios bio-ADM/MR-proADM and BNP/NT-proBNP increased during ARNi-therapy proving improved availability of bioactive peptides. The proportional increase of bio-ADM markedly exceeded BNP increase. Patients converted to ARNi showed similar biomarker patterns irrespective of baseline renin-angiotensin system blocker therapy, i.e. ACEi or ARB (P > .05 for all), indicating that activation of the ADM-axis arises particularly from NEPinhibition.

CONCLUSION

The significant increase of MR-proADM and bio-ADM together with an elevated bioADM/MR-proADM ratio suggest both enhanced formation and reduced breakdown of bioactive ADM following the initiation of ARNi. Activation of the ADM-axis represents a so far unrecognized effect of ARNi.

Plasma Neprilysin Displays No Relevant Association With Neurohumoral Activation in Chronic HFrEF

Background

Neprilysin is a transmembrane endopeptidase involved in the breakdown of a variety of vasoactive peptides and serves as a therapeutic target in heart failure with reduced ejection fraction (HFrEF). This study aimed to investigate the relationship of circulating neprilysin with neurohumoral activation and the impact of plasma neprilysin activity on prognosis in HFrEF.

Methods and Results

A total of 369 chronic HFrEF patients were enrolled prospectively. Plasma neprilysin concentration and activity were determined by a specific ELISA and a fluorometric method. The association between plasma neprilysin and heart failure (HF) severity, neurohumoral activation, ie norepinephrine and absolute renin concentration, as well as all‐cause mortality was assessed. Median plasma neprilysin concentrations and activity levels were 413 pg/mL (interquartile range 0–4111) and 2.36 nmol/mL per minute (interquartile range 1.16–4.59). No correlation could be shown between plasma neprilysin concentrations and activity (r_s=0.09, P=0.088). Plasma neprilysin activity correlated with HF severity reflected by New York Heart Association stage (P=0.003) and tertiles of N‐terminal pro‐B‐type natriuretic peptide (P<0.001), whereas neprilysin concentrations did not (P=0.220; P=0.849). There was no relevant relationship between plasma neprilysin concentrations and activity, with neurohumoral activation reflected by absolute renin concentration (r_s=−0.02, P=0.648; r_s=0.03, P=0.574) or norepinephrine levels (r_s=−0.06, P=0.248; r_s=0.20, P<0.001). Neither circulating neprilysin concentrations nor activity were associated with outcome.

Conclusions

Plasma neprilysin concentrations and activity are not directly related to neurohumoral activation, indicating that neprilysin regulation is either more complex or not correctly mirrored by circulating neprilysin as a biomarker. Circulating neprilysin concentrations and activity were not associated with overall survival, implicating limited prognostic value of plasma neprilysin measurements in HFrEF patients.

Soluble neprilysin, NT-proBNP, and growth differentiation factor-15 as biomarkers for heart failure in dialysis patients (SONGBIRD)

Background

Dialysis patients are at increased risk of HF. However, diagnostic utility of NT-proBNP as a biomarker is decreased in patients on dialysis. GDF-15 and cNEP are biomarkers of distinct mechanisms that may contribute to HF pathophysiology in such cohorts. The aim of this study was to determine whether growth differentiation factor-15 (GDF-15) and circulating neprilysin (cNEP) improve the diagnosis of congestive heart failure (HF) in patients on dialysis.

Methods and results

We compared circulating concentrations of NT-proBNP, GDF-15, and cNEP along with cNEP activity in patients on chronic dialysis without (n = 80) and with HF (n = 73), as diagnosed by clinical parameters and post-dialysis echocardiography. We used correlation, linear and logistic regression as well as receiver operating characteristic (ROC) analyses. Compared to controls, patients with HF had higher median values of NT-proBNP (16,216 [interquartile range, IQR = 27739] vs. 2883 [5866] pg/mL, p < 0.001), GDF-15 (7512 [7084] vs. 6005 [4892] pg/mL, p = 0.014), but not cNEP (315 [107] vs. 318 [124] pg/mL, p = 0.818). Median cNEP activity was significantly lower in HF vs. controls (0.189 [0.223] vs. 0.257 [0.166] nmol/mL/min, p < 0.001). In ROC analyses, a multi-marker model combining clinical covariates, NT-proBNP, GDF-15, and cNEP activity demonstrated best discrimination of HF from controls (AUC = 0.902, 95% CI 0.857–0.947, p < 0.001 vs. base model AUC = 0.785).

Conclusion

We present novel comparative data on physiologically distinct circulating biomarkers for HF in patients on dialysis. cNEP activity but not concentration and GDF-15 provided incremental diagnostic information over clinical covariates and NT-proBNP and may aid in diagnosing HF in dialysis patients.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01597-x) contains supplementary material, which is available to authorized users.

Heart is the Target Organ of Endogenous Cardiac Natriuretic Peptides

This study aimed to evaluate whether the heart is the target organ of endogenous atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in patients with heart failure (HF) with reduced ejection fraction (HFrEF).We measured the plasma levels of cyclic guanosine monophosphate (cGMP), which is a second messenger of ANP and BNP, in the aortic root (AO) and coronary sinus (CS) in 237 patients with HFrEF. Plasma levels of cGMP were significantly higher in the CS than those in the AO in 237 patients with HFrEF (10.0 ± 4.5 versus 10.5 ± 4.3 pmoL/mL, P < 0.0001) and were significantly higher in the CS than those in the AO (8.0 ± 3.6 versus 8.9 ± 3.8 pmoL/mL, P < 0.0001) in mild HF patients (New York Heart Association (NYHA) II, n = 114), but there was no difference in plasma cGMP between the AO and the CS (11.9 ± 4.4 versus 11.9 ± 4.3 pmoL/mL, NS) in severe HF patients (NYHA III-IV, n = 123). In mild HF patients, log (ANP + BNP) in the AO was an independent predictor of (CS-AO) cGMP among hemodynamics and nitrate therapy. There was a significant correlation between log [(CS-AO) ANP + (CS-AO) BNP] and (CS-AO) cGMP (r = 0.455, P < 0.0001) in mild HF patients.These findings indicate that cGMP is produced from the failing heart and that the heart is the target organ of endogenous ANP and BNP in patients with HFrEF. In severe HF patients, cGMP production may be attenuated because of the downregulation of biological receptors and/or increased cGMP degradation in the failing heart.

Sacubitril-Valsartan in a routine community population: attention to volume status critical to achieving target dose

AIMS

In the PARADIGM-heart failure trial, sacubitril-valsartan demonstrated a reduction in heart failure admissions and reduced all-cause mortality in patients with heart failure with reduced ejection fraction. Although real world data have shown similar benefits regarding efficacy and safety, there has been difficulty in achieving the target dose (TD). The factors preventing the achievement of TD remains unclear. This study assesses the tolerability, ability to achieve, and factors linked to attaining TD in a routine clinical population.

METHODS AND RESULTS

This is a retrospective single-centre review of patients switched from angiotensin-converting enzyme inhibitors/angiotensin receptor blockers to sacubitril-valsartan between May 2016 and August 2018. Baseline and follow-up clinical characteristics and biomarker profiles were collected. Univariate and multivariate analyses were used to analyse predictors of achieving TD. Clinical response to sacubitril-valsartan was defined as a reduction in N terminal pro BNP of ≥30%, or an increase in left ventricular ejection fraction of ≥5% compared with baseline values. To date, a total of 322 patients (75% male patients) have been switched to sacubitril-valsartan. Those still in the titration phase were excluded (n = 25). Sacubitril-valsartan was not tolerated in 40 patients (12.4%). Those intolerant were older (73.4 years [68.3, 80.6] vs. 69.1 years [61.2, 76]; P = 0.003) and had worse renal function with estimated glomerular filtration rate (53.5 mL/min/1.72 m² [36.8, 60.2] vs 60 mL/min/1.72 m² [47, 77]; P ≤ 0.001). Of the remaining 257 patients, TD (97/103 mg BD) was achieved in 194 patients (75.5%), while 37 patients (11.4%) were maintained on 49/51 mg BD and 26 patients (8.1%) remained on 24/26 mg BD. Symptomatic hypotension (74.6%) was the main impediment to attaining TD, followed by renal deterioration (12.7%), and to a lesser extent hyperkalaemia and gastrointestinal symptoms (4.8% each). Diuretic dose decrease was achieved in 37.2% of patients, and this was the strongest independent predictor of achieving TD (odds ratio = 2.1; 95% confidence interval [1.16, 3.8]; P = 0.014). Responder status by N terminal pro BNP criterion was observed in 99 of 214 patients (46.3%) while 70 of 142 (49.3%) attained the left ventricular ejection fraction response status. Achieving this response was independently linked to achieving TD.

CONCLUSIONS

Sacubitril-valsartan was well tolerated. Achievement of TD was possible in the majority of the cohort and was linked to response metrics. Reduction in diuretic was required in a large percentage of the population and was the strongest predictor of attaining TD. Therefore, careful clinical attention to volume status assessment is essential to maximising the benefits of sacubitril-valsartan.

Association Between Cardiac Natriuretic Peptides and Lipid Profile: a Systematic Review and Meta-Analysis

Cardiac natriuretic peptides (NPs) play a fundamental role in maintaining cardiovascular (CV) and renal homeostasis. Moreover, they also affect glucose and lipid metabolism. We performed a systematic review and meta-analysis of studies investigating the association of NPs with serum lipid profile. A PubMed and Scopus search (2005–2018) revealed 48 studies reporting the association between NPs and components of lipid profile [total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc) and triglycerides (TG)]. Despite high inconsistency across studies, NPs levels were inversely associated with TC [k = 32; pooled r = −0.09; I² = 90.26%], LDLc [k = 31; pooled r = −0.09; I² = 82.38%] and TG [k = 46; pooled r = −0.11; I² = 94.14%], while they were directly associated with HDLc [k = 41; pooled r = 0.06; I² = 87.94%]. The relationship with LDLc, HDLc and TG lost significance if only studies on special populations (works including subjects with relevant acute or chronic conditions that could have significantly affected the circulating levels of NPs or lipid profile) or low-quality studies were taken into account. The present study highlights an association between higher NP levels and a favorable lipid profile. This confirms and extends our understanding of the metabolic properties of cardiac NPs and their potential in CV prevention.

Educational Recommendations on Selected Analytical and Clinical Aspects of Natriuretic Peptides with a Focus on Heart Failure: A Report from the IFCC Committee on Clinical Applications of Cardiac Bio-Markers

The IFCC Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has directives and initiatives focused on providing evidence-based educational resources to aid and improve understanding around key analytical and clinical aspects of cardiac biomarkers used in clinical practice and the research setting. As a task force, we have previously published position statements and recommendations focused on use and analytical aspects of high-sensitivity cardiac troponin assays. The current educational document is the first from the C-CB highlighting important biochemical, analytical, and clinical aspects as they relate to the natriuretic peptides (NPs), including B-type natriuretic peptide (BNP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP), with a focus on heart failure.

Detection of Neprilysin-Derived BNP Fragments in the Circulation: Possible Insights for Targeted Neprilysin Inhibition Therapy for Heart Failure

BACKGROUND

Entresto™ is a new heart failure (HF) therapy that includes the neprilysin (NEP) inhibitor sacubitril. One of the NEP substrates is B-type natriuretic peptide (BNP); its augmentation by NEP inhibition is considered as a possible mechanism for the positive effects of Entresto. We hypothesized that the circulating products of BNP proteolysis by NEP might reflect NEP impact on the metabolism of active BNP. We suggest that NEP-based BNP cleavage at position 17–18 results in BNP ring opening and formation of a novel epitope with C-terminal Arg-17 (BNP-neo17 form). In this study, we use a specific immunoassay to explore BNP-neo17 in a rat model and HF patient plasma.

METHODS

We injected BNP into rats, with or without NEP inhibition with sacubitril. BNP-neo17 in plasma samples at different time points was measured with a specific immunoassay with neglectable cross-reactivity to intact forms. BNP-neo17 and total BNP were measured in EDTA plasma samples of HF patients.

RESULTS

BNP-neo17 generation in rat circulation was prevented by NEP inhibition. The maximum 13.2-fold difference in BNP-neo17 concentrations with and without sacubitril was observed at 2 min after injection. BNP-neo17 concentrations in 32 HF patient EDTA plasma samples ranged from 0 to 37 pg/mL (median, 5.4; interquartile range, 0–9.1). BNP-neo17/total BNP had no correlation with total BNP concentration (with r = −0.175, P = 0.680) and showed variability among individuals.

CONCLUSIONS

BNP-neo17 formation is NEP dependent. Considering that BNP-neo17 is generated from the active form of BNP by NEP, we speculate that BNP-neo17 may reflect both the NEP activity and natriuretic potential and serve for HF therapy guidance.

Differential Regulation of ANP and BNP in Acute Decompensated Heart Failure: Deficiency of ANP

OBJECTIVES

This study investigated the differential regulation of circulating atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in patients with acute decompensated heart failure (ADHF) and tested the hypothesis that a relative deficiency of ANP exists in a subgroup of patients with ADHF.

BACKGROUND

The endocrine heart releases the cardiac hormones ANP and BNP, which play a key role in cardiovascular (CV), renal, and metabolic homeostasis. In heart failure (HF), both plasma ANP and BNP are increased as a compensatory homeostatic response to myocardial overload.

METHODS

ANP and BNP concentrations were measured in a small group of patients with ADHF (n = 112). To support this study's goal, a total of 129 healthy subjects were prospectively recruited to establish contemporary normal values for ANP and BNP. Plasma 3',5'cyclic guanosine monophosphate (cGMP), ejection fraction (EF), and body mass index (BMI) were measured in these subjects.

RESULTS

In cases of ADHF, 74% of patients showed elevated ANP and BNP. Importantly, 26% of patients were characterized as having normal ANP (21% of this subgroup had normal ANP and elevated BNP). Cyclic GMP was lowest in the ADHF group with normal levels of ANP (p < 0.001), whereas BMI and EF were inversely related to ANP levels (p = 0.003).

CONCLUSIONS

Among a subgroup of patients hospitalized with ADHF, the presence of an ANP deficiency is consistent with a differential regulation of ANP and BNP and suggests the existence of a potentially compromised compensatory cardiac endocrine response. These findings have implications for the pathophysiology, diagnostics, and therapeutics of human HF.

Evolution of B-type natriuretic peptide and N-terminal pro-brain natriuretic peptide during acute decompensated heart failure in a chronic heart failure patient with reduced ejection fraction treated with Sacubitril/Valsartan: a case report

Background

B-type natriuretic peptide (BNP) and the N-terminal proBNP (NT-proBNP) exhibit different evolution in chronic heart failure patients with reduced ejection fraction treated with Sacubitril/Valsartan; BNP increasing or remaining stable, while NT-proBNP decreases. However, how this difference translates upon acute decompensation is unknown.

Case summary

Herein, we described in a 78-year-old woman with chronic heart failure with reduced ejection fraction treated with Sacubitril/Valsartan who had acute decompensated heart failure (ADHF). BNP and NT-proBNP were markedly high during ADHF and showed parallel return to baseline level after clinical improvement.

Discussion

BNP and NT-proBNP retained similar value for the diagnosis of ADHF in patient treated with Sacubitril/Valsartan. These findings strongly suggest that either BNP or NT-proBNP can be used indifferently in this context, while their relative use is debated in chronic heart failure.

Circulating Neprilysin in Patients With Heart Failure and Preserved Ejection Fraction

BACKGROUND

In heart failure with reduced ejection fraction (HFrEF), elevated soluble neprilysin (sNEP) levels are associated with an increased risk of cardiovascular death, and its inhibition with sacubitril/valsartan has improved survival.

OBJECTIVES

This study sought to determine the relevance of sNEP as a biomarker in heart failure with preserved ejection fraction (HFpEF) and to compare circulating sNEP levels in patients with HFpEF with normal controls.

METHODS

A case-control study was performed in 242 symptomatic patients with HFpEF previously enrolled in the Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure with Preserved Ejection Fraction (RELAX) and Nitrates's Effect on Activity Tolerance in Heart Failure With Preserved Ejection (NEAT-HFpEF) clinical trials and 891 asymptomatic subjects without HF or diastolic dysfunction (confirmed by NT-proBNP levels <200 pg/ml and echocardiography) who were enrolled in the Prevalence of Asymptomatic Left Ventricular Dysfunction study. sNEP was measured using a sandwich enzyme-linked immunosorbent assay (ELISA) in all subjects.

RESULTS

Overall, sNEP levels were lower in HFpEF compared with controls (3.5 ng/ml; confidence interval [CI]: 2.5 to 4.8 vs. 8.5 ng/ml; CI: 7.2 to 10.0; p < 0.001). After adjusting for age, gender, body mass index (BMI), and smoking history, mean sNEP levels were also lower in HFpEF compared with controls (4.0 ng/ml [CI: 2.7 to 5.4] vs. 8.2 ng/ml [CI: 6.8 to 9.7]; p = 0.002). The cohorts were propensity matched based on age, BMI, diabetes, hypertension, smoking history, and renal function, and sNEP levels remained lower in HFpEF compared with controls (median 2.4 ng/ml [interquartile range: 0.6 to 27.7] vs. 4.9 ng/ml [interquartile range: 1.2 to 42.2]; p = 0.02).

CONCLUSIONS

Patients with HFpEF on average have significantly lower circulating sNEP levels compared with controls. These findings challenge our current understanding of the complex biology of circulating sNEP in HFpEF.

Atrial Natriuretic Peptide: A Molecular Target of Novel Therapeutic Approaches to Cardio-Metabolic Disease

Atrial natriuretic peptide (ANP) is a cardiac hormone with pleiotropic cardiovascular and metabolic properties including vasodilation, natriuresis and suppression of the renin-angiotensin-aldosterone system. Moreover, ANP induces lipolysis, lipid oxidation, adipocyte browning and ameliorates insulin sensitivity. Studies on ANP genetic variants revealed that subjects with higher ANP plasma levels have lower cardio-metabolic risk. In vivo and in humans, augmenting the ANP pathway has been shown to exert cardiovascular therapeutic actions while ameliorating the metabolic profile. MANP is a novel designer ANP-based peptide with greater and more sustained biological actions than ANP in animal models. Recent studies also demonstrated that MANP lowers blood pressure and inhibits aldosterone in hypertensive subjects whereas cardiometabolic properties of MANP are currently tested in an on-going clinical study in hypertension and metabolic syndrome. Evidence from in vitro, in vivo and in human studies support the concept that ANP and related pathway represent an optimal target for a comprehensive approach to cardiometabolic disease.

Neprilysin inhibition: a new therapeutic option for type 2 diabetes?

Neprilysin is a widely expressed peptidase with broad substrate specificity that preferentially hydrolyses oligopeptide substrates, many of which regulate the cardiovascular, nervous and immune systems. Emerging evidence suggests that neprilysin also hydrolyses peptides that play an important role in glucose metabolism. In recent studies in humans, a dual angiotensin receptor-neprilysin inhibitor (ARNi) improved glycaemic control and insulin sensitivity in individuals with type 2 diabetes and/or obesity. Moreover, preclinical studies have also reported that neprilysin inhibition, alone or in combination with renin-angiotensin system blockers, elicits beneficial effects on glucose homeostasis. Since neprilysin inhibitors have been approved for the treatment of heart failure, their repurposing for treating type 2 diabetes would provide a novel therapeutic strategy. In this review, we evaluate existing evidence from preclinical and clinical studies in which neprilysin is deleted/inhibited, we highlight potential mechanisms underlying the beneficial glycaemic effects of neprilysin inhibition, and discuss possible deleterious effects that may limit the efficacy and safety of neprilysin inhibitors in the clinic. We also review the favourable impact neprilysin inhibition can have on diabetic complications, in addition to glucose control. Finally, we conclude that neprilysin inhibitors may be a useful therapeutic option for treating type 2 diabetes; however, their combination with angiotensin II receptor blockers is needed to circumvent deleterious consequences of neprilysin inhibition alone.

Sacubitril/valsartan augments postprandial plasma concentrations of active GLP-1 when combined with sitagliptin in men

CONTEXT

Combined inhibition of neprilysin and dipeptidyl peptidase 4 (DPP-4) has been shown to augment plasma concentrations of glucagon-like peptide-1(GLP-1) in animal models, but whether this occurs in humans is unknown.

OBJECTIVE

To investigate the effects of inhibition of neprilysin by sacubitril/valsartan alone or in combination with a DPP-4 inhibitor (sitagliptin) on plasma concentrations of GLP-1 in healthy men.

DESIGN

Two open-labeled crossover studies were performed in human subjects.

SETTING

General community.

PARTICIPANTS

Nine and 10 healthy young males were included in study 1 and study 2, respectively.

INTERVENTION

Study participants received a standardized meal (34% carbohydrates, 45% fat, 21% protein, total caloric content of 2106kJ) combined with a prior dose of either sacubitril/valsartan (194/206mg) or control in study 1, and in study 2, with a prior dose of sitagliptin (2x100mg, given ∼10 hours apart) either alone or with sacubitril/valsartan (194/206mg).

MAIN OUTCOME MEASURES

Plasma concentrations of total and intact GLP-1.

RESULTS

Sacubitril/valsartan increased postprandial plasma concentrations of total GLP-1 by 67% (tAUC0-240min: 3929±344 vs. 2348±181 min × pmol/L P=0.0023), and increased concentrations of intact GLP-1 plasma concentrations more than sitagliptin alone (tAUC0-240min: 1021±114 vs. 660±80 min × pmol/L, P=0.01). Plasma concentrations of glucose, insulin, and GIP were not significantly (P>0.10) changed upon sacubitril/valsartan treatment.

CONCLUSIONS

Sacubitril/valsartan combined with a DPP-4 inhibitor lead to markedly higher concentrations of intact GLP-1 than DPP-4 inhibition alone, supporting a role for both neprilysin and DPP-4 in the metabolism of GLP-1 in humans, a finding which may have therapeutic implications.