Molecular Biology of the Natriuretic Peptide System

Comparison of sacubitril/valsartan with olmesartan for hypertension: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of sacubitril/valsartan versus olmesartan remains controversial for the control of hypertension. We conduct a systematic review and meta-analysis to explore the influence of sacubitril/valsartan versus olmesartan on the control of hypertension.

METHODS

We have searched PubMed, Embase, Web of science, EBSCO, and Cochrane library databases through July 2023 for randomized controlled trials assessing the effect of sacubitril/valsartan versus olmesartan on the control of hypertension. This meta-analysis is performed using the random-effect model or fixed-effect model based on the heterogeneity.

RESULTS

Seven randomized controlled trials and 3677 patients were included in the meta-analysis. Overall, compared with olmesartan treatment for hypertension, sacubitril/valsartan treatment was associated with substantially decreased systolic blood pressure (mean difference [MD] = -4.58; 95% confidence interval [CI] = -7.90 to -1.25; P = .007), diastolic blood pressure (MD = -1.70; 95% CI = -3.24 to -0.17; P = .03), and pulse pressure (MD = -2.31; 95% CI = -4.41 to -0.21; P = .03), as well as improved systolic blood pressure control (odds ratio [OR] = 1.65; 95% CI = 1.15 to 2.38; P = .006), but had no influence on diastolic blood pressure control (OR = 1.33; 95% CI = 0.93 to 1.88; P = .11) or adverse events (OR = 1.06; 95% CI = 0.90 to 1.24; P = .51).

CONCLUSIONS

Sacubitril/valsartan is better than olmesartan for the reduction of blood pressure for patients with hypertension.

Developmental roles of natriuretic peptides and their receptors

Natriuretic peptides and their receptors are implicated in the physiological control of blood pressure, bone growth, and cardiovascular and renal homeostasis. They mediate their action through the modulation of intracellular levels of cGMP and cAMP, two second-messengers that have broad biological roles. In this review, we briefly describe the major players of this signaling pathway and their physiological roles in the adult, and discuss several reports describing their activity in the control of various aspects of embryonic development in several species. While the core components of this signaling pathway are well conserved, their functions have diverged in the embryo and the adult to control a diverse array of biological processes.

Efficacy and safety of sacubitril/allisartan for the treatment of primary hypertension: a phase 2 randomized, double-blind study

This randomized, double-blind phase 2 study assessed the efficacy and safety of sacubitril/allisartan, an angiotensin receptor neprilysin inhibitor, compared with placebo in Chinese patients with mild to moderate hypertension. Eligible patients aged 18-75 years (n = 235) with mild to moderate hypertension were randomized to receive sacubitril/allisartan 120 mg (n = 52), sacubitril/allisartan 240 mg (n = 52), sacubitril/allisartan 480 mg (n = 52), placebo (n = 26) or olmesartan 20 mg (n = 53) once daily for 8 weeks. The primary end point was a reduction in clinic systolic blood pressure from baseline with different doses of sacubitril/allisartan versus placebo at 8 weeks. Secondary efficacy variables included clinic diastolic blood pressure and 24-h ambulatory blood pressure for the comparison between sacubitril/allisartan and placebo at 8 weeks. Safety assessments included all adverse events and serious adverse events. Sacubitril/allisartan 480 mg/day provided a significantly greater reduction in clinic systolic blood pressure than placebo at 8 weeks (between-treatment difference: -9.1 mmHg [95% confidence interval -1.6 to -16.6 mmHg], P = 0.02). There were also significant reductions in 24-h, daytime and nighttime systolic and diastolic blood pressure for sacubitril/allisartan 480 mg/day compared with placebo (P ≤ 0.03). Similarly, a greater reduction in daytime systolic blood pressure was observed for sacubitril/allisartan 240 mg/day compared with placebo (between-treatment difference: -7.3 mmHg [95% confidence interval -0.5 to -14.0 mmHg], P = 0.04). Sacubitril/allisartan was well tolerated, and no cases of angioedema were reported. Sacubitril/allisartan is effective for the treatment of hypertension in Chinese patients and is well tolerated.

PPAR Alpha Activation by Clofibrate Alleviates Ischemia/Reperfusion Injury in Metabolic Syndrome Rats by Decreasing Cardiac Inflammation and Remodeling and by Regulating the Atrial Natriuretic Peptide Compensatory Response

Metabolic syndrome (MetS) is a cluster of factors that increase the risk of developing diabetes, stroke, and heart failure. The pathophysiology of injury by ischemia/reperfusion (I/R) is highly complex and the inflammatory condition plays an important role by increasing matrix remodeling and cardiac apoptosis. Natriuretic peptides (NPs) are cardiac hormones with numerous beneficial effects mainly mediated by a cell surface receptor named atrial natriuretic peptide receptor (ANPr). Although NPs are powerful clinical markers of cardiac failure, their role in I/R is still controversial. Peroxisome proliferator-activated receptor α agonists exert cardiovascular therapeutic actions; however, their effect on the NPs’ signaling pathway has not been extensively studied. Our study provides important insight into the regulation of both ANP and ANPr in the hearts of MetS rats and their association with the inflammatory conditions caused by damage from I/R. Moreover, we show that pre-treatment with clofibrate was able to decrease the inflammatory response that, in turn, decreases myocardial fibrosis, the expression of metalloprotease 2 and apoptosis. Treatment with clofibrate is also associated with a decrease in ANP and ANPr expression.

Human Alpha-1 Antitrypsin Attenuates ENaC and MARCKS and Lowers Blood Pressure in Hypertensive Diabetic db/db Mice

Hypertension may develop before or after the onset of diabetes and it is known to increase the risk of developing diabetic nephropathy. Alpha-1 antitrypsin (AAT) is a multi-functional protein with beneficial effects in various diseases but its role in reducing blood pressure in the diabetic kidney has not been thoroughly studied. Like blood pressure, epithelial sodium channels (ENaC) and its adaptor protein myristoylated alanine-rich C-kinase substrate (MARCKS) are regulated by circadian rhythms. Our hypothesis is that administration of human AAT (hAAT) reduces blood pressure in hypertensive diabetic mice by attenuating membrane expression of ENaC and its association with the actin cytoskeleton. First, we show hAAT administration results in reduced blood pressure in diabetic db/db mice compared to vehicle treatment in both the inactive and active cycles. Western blotting and immunohistochemistry analyses showed a reduction of ENaC and the actin cytoskeleton protein, MARCKS in the kidneys of diabetic db/db mice treated with hAAT compared to vehicle. hAAT treatment resulted in elevated amounts of extracellular vesicles present in the urine of diabetic db/db mice compared to vehicle treatment both in the inactive and active cycles. Multiple hexosylceramides, among other lipid classes increased in urinary EVs released from hAAT treated hypertensive diabetic mice compared to vehicle treated mice. Taken together, these data suggest hAAT treatment could normalize blood pressure in the diabetic kidney in a mechanism involving attenuation of renal ENaC and MARCKS protein expression and possibly ceramide metabolism to hexosylceramide in kidney cells.

Progress and prospects of Sacubitril/Valsartan: Based on heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is present in nearly half of patients with heart failure. The prevalence of heart failure with normal or near-normal ejection fractions increases more rapidly than in patients with reduced ejection fractions. Angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), aldosterone antagonist, β-blocker, and calcium channel blocker have not shown significant efficacy in HFpEF clinical trials. Sacubitril/Valsartan, combined angiotensin receptor blocker (Valsartan) with neprilysin inhibitor (Sacubitril), was the first-of-its-kind angiotensin receptor-neprilysin inhibitor (ARNI) to be developed. It has shown significant efficacy on HFpEF in recent studies. It is considered that most of the current Sacubitril/Valsartan studies are still concentrated in the field of heart failure, especially heart failure with reduced ejection fraction (HFrEF). This review discusses the latest advances in cardiovascular, renal, and metabolic aspects of Sacubitril/Valsartan, mainly in HFpEF, providing more evidence for further future research on Sacubitril/Valsartan and raising issues that should be paid attention. At the same time, this review will introduce the academic consensus on Sacubitril/Valsartan in treating HFpEF in China.

Angiotensin Receptor-Neprilysin Inhibitor Attenuates Cardiac Hypertrophy and Improves Diastolic Dysfunction in A Mouse Model of Heart Failure with Preserved Ejection Fraction

LCZ696, an angiotensin receptor-neprilysin inhibitor, has shown promising clinical efficacy in patients with heart failure (HF) with reduced ejection fraction. However, its potential effects on heart failure with preserved ejection fraction (HFpEF) are still not fully understood. We evaluated the effect of LCZ696 on HFpEF in transverse aortic constriction mice and compared it with the effect of the angiotensin receptor blocker valsartan. We found that LCZ696 improved cardiac diastolic function by reducing ventricular hypertrophy and fibrosis in mice with overload-induced diastolic dysfunction. In addition, there was superior inhibition of LCZ696 than stand-alone valsartan. As a potential underlying mechanism, we demonstrated that LCZ696 behaves as a potent suppressor of calcium-mediated calcineurin-NFAT signaling transduction pathways. Hence, we demonstrated the protective effects of LCZ696 in overload-induced HFpEF and provided a pharmaceutical therapeutic strategy for related diseases.

Sacubitril/valsartan, sodium‐glucose cotransporter 2 inhibitors, and vericiguat for congestive heart failure therapy

Heart failure is associated with notable morbidity and mortality, and therefore, novel therapies are needed. This minireview focused on the effects and mechanisms of action of sacubitril/valsartan, sodium‐glucose cotransporter 2 inhibitors and vericiguat in heart failure patients. A systematic review of the current literature was conducted. Seventeen randomised clinical trials regarding the effects of these drug classes were included. The mechanism of action of each treatment could improve pathophysiological imbalances present in heart failure. All three drug classes revealed a reduction in hospitalisations for heart failure or death from cardiovascular causes in patients with reduced ejection fraction. Sacubitril/valsartan also reduced hospitalisations and death from cardiovascular causes in patients with mid‐range ejection fraction, but not in patients with preserved ejection fraction. The sodium‐glucose cotransporter 2 inhibitors, sotagliflozin and empagliflozin, reduced hospitalisations and death from cardiovascular causes in heart failure patients with preserved ejection fraction. None of the three drug classes was associated with a higher prevalence of treatment discontinuation due to increases in adverse effects in large‐scale randomised clinical trials compared with placebo. Further studies are required to clarify the extent of effects of these medications in different subpopulations—especially in patients with mid‐range and preserved ejection fraction.

Efficacy of sacubitril/valsartan versus olmesartan in Japanese patients with essential hypertension: a randomized, double-blind, multicenter study

This phase III study assessed the efficacy and safety of sacubitril/valsartan compared with those of olmesartan in Japanese patients with essential hypertension. Patients (n = 1161, aged ≥20 years) with mild to moderate hypertension (mean sitting systolic blood pressure [msSBP] ≥150 to <180 mmHg) were randomized to receive sacubitril/valsartan 200 mg (n = 387), sacubitril/valsartan 400 mg (n = 385), or olmesartan 20 mg (n = 389) once daily for 8 weeks. The primary assessment was a reduction in msSBP from baseline with sacubitril/valsartan 200 mg vs. olmesartan 20 mg at Week 8. Secondary assessments included msSBP reduction with sacubitril/valsartan 400 mg vs. olmesartan at Week 8 and reductions in mean sitting diastolic blood pressure (msDBP), mean sitting pulse pressure (msPP), and overall blood pressure (BP) control rate for all treatment groups at Week 8. Sacubitril/valsartan 200 mg provided a significantly greater reduction in msSBP from baseline than olmesartan at Week 8 (between-treatment difference: −5.01 mmHg [95% confidence interval: −6.95 to −3.06 mmHg, P < 0.001 for noninferiority and superiority]). Greater reductions in msSBP with sacubitril/valsartan 400 mg vs. olmesartan, as well as in msDBP and msPP with both doses of sacubitril/valsartan vs. olmesartan (P < 0.05 for all), were also observed. Patients treated with sacubitril/valsartan achieved an overall higher BP control rate. The safety and tolerability profiles of sacubitril/valsartan were generally comparable to those of olmesartan. The adverse event rate with sacubitril/valsartan was not dose-dependent. Treatment with sacubitril/valsartan was effective and provided superior BP reduction, with a higher proportion of patients achieving target BP goals than treatment with olmesartan in Japanese patients with mild to moderate essential hypertension.

Treatment with sacubitril/valsartan is effective and provided superior blood pressure (BP) reductions with a higher proportion of patients achieving target BP goals versus olmesartan in Japanese patients with mild-to-moderate essential hypertension.

Schisandrin A protects against isoproterenol‑induced chronic heart failure via miR‑155

Schisandrin A (Sch A) has a protective effect on cardiomyocytes. Circulating miR-155 levels are related to chronic heart failure (CHF). The present study aimed to clarify the role and the molecular mechanism of Sch A in CHF. C57BL/6JGpt mice were used for an isoproterenol (ISO)-induced CHF model to collect heart samples. Echocardiography was employed to detect heartbeat indicators. The degree of myocardial hypertrophy was evaluated based on the measurement of heart weight (HW), body weight (BW) and tibia length (TL) and the observation using hematoxylin-eosin staining. Sprague-Dawley rats were purchased for the separation of neonatal rat ventricular myocytes (NRVMs), which were treated with ISO for 24 h. Transfection regulated the level of miR-155. The viability of NRVMs was detected via MTT assay. The mRNA and protein levels were measured via reverse transcription-quantitative PCR and western blotting and immunofluorescence was used to detect the content of α-smooth muscle actin (α-SMA). Treatment with ISO resulted in rising left ventricular posterior wall thickness, intra-ventricular septum diastole, left ventricular end diastolic diameter, left ventricular end systolic diameter, HW/BW, HW/TL and falling ejection fraction and fractional shortening, the trend of which could be reversed by Sch A. Sch A ameliorated myocardial hypertrophy in CHF mice. In addition, Sch A inhibited ISO-induced upregulated expressions of atrial natriuretic peptide, B-type natriuretic peptide, B-myosin heavy chain and miR-155 in myocardial tissue. Based on the results in vitro, Sch A had no significant effect on the viability of NRVMs when its concentration was <24 µmol/l. Sch A inhibited the levels of miR-155, α-SMA and the phosphorylation levels of AKT and cyclic AMP response-element binding protein (CREB) in ISO-induced NRVMs, which was reversed by the upregulation of miR-155. Schisandrin A mediated the AKT/CREB signaling pathway to prevent CHF by regulating the expression of miR-155, which may shed light on a possible therapeutic target for CHF.

The benefits of sacubitril-valsartan in patients with acute myocardial infarction: a systematic review and meta-analysis

AIMS

We aimed to investigate whether sacubitril-valsartan could further improve the prognosis, cardiac function, and left ventricular (LV) remodelling in patients following acute myocardial infarction (AMI).

METHODS AND RESULTS

We searched the PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI) from inception to 10 May 2021 to identify potential articles. Randomized controlled trials (RCTs) meeting the inclusion criteria were included and analysed. Thirteen RCTs, covering 1358 patients, were analysed. Compared with angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB), sacubitril-valsartan did not significantly reduced the cardiovascular mortality [risk ratio (RR) 0.65, 95% confidence interval (CI) 0.22 to 1.93, P = 0.434] and the rate of myocardial reinfarction (RR 0.65, 95% CI 0.29 to 1.46, P = 0.295) of patients following AMI, but the rate of hospitalization for heart failure (HF) (RR 0.48, 95% CI 0.35 to 0.66, P < 0.001) and the change of LV ejection fraction (LVEF) [weighted mean difference (WMD) 5.49, 95% CI 3.62 to 7.36, P < 0.001] were obviously improved. The N-terminal pro-brain natriuretic peptide (NT-ProBNP) level (WMD -310.23, 95% CI -385.89 to -234.57, P < 0.001) and the LV end-diastolic dimension (LVEDD) (WMD -3.16, 95% CI -4.59 to -1.73, P < 0.001) were also significantly lower in sacubitril-valsartan group than in ACEI/ARB group. Regarding safety, sacubitril-valsartan did not increase the risk of hypotension, hyperkalaemia, angioedema, and cough.

CONCLUSIONS

This meta-analysis suggests that early administration of sacubitril-valsartan may be superior to conventional ACEI/ARB to decrease the risk of hospitalization for HF, improve the cardiac function, and reverse the LV remodelling in patients following AMI.

Cardioprotective effects of early intervention with sacubitril/valsartan on pressure overloaded rat hearts

Left ventricular remodeling due to pressure overload is associated with poor prognosis. Sacubitril/valsartan is the first-in-class Angiotensin Receptor Neprilysin Inhibitor and has been demonstrated to have superior beneficial effects in the settings of heart failure. The aim of this study was to determine whether sacubitril/valsartan has cardioprotective effect in the early intervention of pressure overloaded hearts and whether it is superior to valsartan alone. We induced persistent left ventricular pressure overload in rats by ascending aortic constriction surgery and orally administrated sacubitril/valsartan, valsartan, or vehicle one week post operation for 10 weeks. We also determined the effects of sacubitril/valsartan over valsartan on adult ventricular myocytes and fibroblasts that were isolated from healthy rats and treated in culture. We found that early intervention with sacubitril/valsartan is superior to valsartan in reducing pressure overload-induced ventricular fibrosis and in reducing angiotensin II-induced adult ventricular fibroblast activation. While neither sacubitril/valsartan nor valsartan changes cardiac hypertrophy development, early intervention with sacubitril/valsartan protects ventricular myocytes from mitochondrial dysfunction and is superior to valsartan in reducing mitochondrial oxidative stress in response to persistent left ventricular pressure overload. In conclusion, our findings demonstrate that sacubitril/valsartan has a superior cardioprotective effect over valsartan in the early intervention of pressure overloaded hearts, which is independent of the reduction of left ventricular afterload. Our study provides evidence in support of potential benefits of the use of sacubitril/valsartan in patients with resistant hypertension or in patients with severe aortic stenosis.

Effects of angiotensin receptor neprilysin inhibitor on renal function in patients with heart failure: a systematic review and meta-analysis

The angiotensin receptor neprilysin inhibitor (ARNI) has been recommended as a first-line treatment in patients with heart failure (HF). However, the effects of ARNI on renal function remain controversial.The PubMed, Embase, the Cochrane Library of Trials and Web of Science were searched in the period from inception to 31 January 2021. Randomised controlled trial, cohort studies and observational studies reporting at least one of renal function indicators were included.In patients with HF with reduced ejection fraction (HFrEF), ARNI did not lead to a significant decrease in estimated glomerular filtration rate (eGFR, p=0.87), and the risk of worsening renal function (WRF) dropped by 11% compared with control group. Though the level of serum creatinine (SCr) and serum potassium had a slight increase (p=0.01; p=0.02), in contrast to the baseline level, but without clinical significance. In patients with HF with preserved ejection fraction (HFpEF), the level of SCr and serum potassium did not have a significant change, and patients with HFpEF assigned to ARNI had a much lower rate of WRF (p=0.0007). In contrast to control group, both patients with HFrEF and HFpEF had a less decrease in eGFR and a lower rate of hyperkalaemia in ARNI group.ARNI did not lead to a significant decrease in eGFR in HFrEF. Compared with control group, ARNI could delay the progression of decrease in eGFR and result in less events of hyperkalaemia in patients with HF. Besides, patients with HFpEF had a lower rate in the events of WRF.

A study of the sequential treatment of acute heart failure with sacubitril/valsartan by recombinant human brain natriuretic peptide: A randomized controlled trial

This study aimed to investigate the effects of the basic treatment for heart failure and sequential treatment with rh-brain natriuretic peptide (rhBNP) alone or the combination of rhBNP and sacubitril/valsartan. Cardiac structure, pulmonary artery pressure, inflammation and oxidative stress in patients with acute heart failure were evaluated.Three hundred patients with acute heart failure were included. According to the random number table method, the patients were divided into 3 groups of 100 patients per group: the standard treatment group (treated with an angiotensin-converting enzyme inhibitor, β receptor blocker, and corticosteroid antagonist), rhBNP group (basic treatment combined with rhBNP) and sequential treatment group (basic treatment for heart failure combined with rhBNP followed by sacubitril/valsartan). The changes in NT-probrain natriuretic peptide (BNP) levels, cardiac troponin T (cTnT) levels, cardiac structure, pulmonary artery pressure, and the levels inflammatory factors and oxidative stress factors were compared among the 3 groups at 1, 4, 12, and 36 weeks after treatment.The sequential treatment group displayed superior outcomes than the standard treatment group and the rhBNP group in terms of left atrium diameter, left ventricular end diastolic volume, left ventricular ejection fraction, pulmonary artery pressure, NT-proBNP levels, and cTnT levels, which respond to damage to the heart structure and myocardium. This result may be related to the decreased levels of inflammatory factors and the correction of oxidative stress imbalance.Sacubitril/valsartan significantly reduce the serum levels of inflammatory factors in patients with acute heart failure while decreasing the levels of oxidizing factors and increasing the levels of antioxidant factors. These changes may be one of the explanations for the better cardiac structure and better pulmonary artery pressure observed in the sequential treatment group.

Renal protection in chronic heart failure: focus on sacubitril/valsartan

Chronic kidney disease (CKD) is highly prevalent in patients with chronic heart failure (CHF) and increases the risk of overall and cardiovascular (CV) mortality. Despite evidence supporting the effectiveness of angiotensin-converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers, and mineralocorticoid receptor antagonists in decreasing mortality in patients with CHF, CKD hampers the optimization of standard pharmacologic therapy for heart failure. Therefore, other treatment options are needed to optimize treatment outcomes in CHF patients with CKD. The first-in-class angiotensin receptor-neprilysin inhibitor, sacubitril/valsartan, has a complementary activity that counteracts the potential unwanted long-term effects of over-activation of the renin–angiotensin–aldosterone system. Sacubitril/valsartan reduced the risk of CV mortality compared to standard therapy with an ACE-I in patients with heart failure with reduced ejection fraction (HFrEF) in the PARADIGM-HF trial and has been shown to be safe and effective in a broad range of HFrEF patients. However, data on the efficacy and tolerability of sacubitril/valsartan in patients with more advanced CKD are limited. This review discusses the evidence for the role of sacubitril/valsartan in providing additional renal benefit in patients with HFrEF. Data from clinical trials and real-world experience in patients with HFrEF and advanced CKD support the benefits of dual angiotensin/neprilysin inhibition across the breadth of kidney disease stages, including patients with significant renal impairment that was not reported in the pivotal PARADIGM-HF trial, and suggests a central role for the cardiac benefits of sacubitril/valsartan in nephroprotection.

Integrative Proteomic and Metabolomic Analysis Reveals Metabolic Phenotype in Mice With Cardiac-Specific Deletion of Natriuretic Peptide Receptor A

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are important biological markers and cardiac function regulators. Natriuretic peptide receptor A (NPRA) binds to an ANP or BNP ligand and induces transmembrane signal transduction by elevating the intracellular cyclic guanosine monophosphate (cGMP) levels. However, the metabolic phenotype and related mechanisms induced by NPRA deletion remain ambiguous. Here, we constructed myocardial-specific NPRA deletion mice and detected the heart functional and morphological characteristics by histological analysis and explored the altered metabolic pattern and the expression patterns of proteins by liquid chromatography-mass spectrometry (LC-MS)-based omics technology. NPRA deficiency unexpectedly did not result in significant cardiac remodeling or dysfunction. However, compared with the matched littermates, NPRA-deficient mice had significant metabolic differences. Metabolomic analysis showed that the metabolite levels varied in cardiac tissues and plasma. In total, 33 metabolites were identified in cardiac tissues and 54 were identified in plasma. Compared with control mice, NPRA-deficient mice had 20 upregulated and six downregulated metabolites in cardiac tissues and 25 upregulated and 23 downregulated metabolites in plasma. Together, NPRA deficiency resulted in increased nucleotide biosynthesis and histidine metabolism only in heart tissues and decreased creatine metabolism only in plasma. Further proteomic analysis identified 136 differentially abundant proteins in cardiac tissues, including 54 proteins with higher abundance and 82 proteins with lower abundance. Among them, cytochrome c oxidase subunit 7c and 7b (Cox7c, Cox7b), ATP synthase, H+ transporting, mitochondrial Fo complex subunit F2 (ATP5J2), ubiquinol-cytochrome c reductase, complex III subunit X (Uqcr10), and myosin heavy chain 7 (Myh7) were mainly involved in related metabolic pathways. These results revealed the essential role of NPRA in metabolic profiles and may elucidate new underlying pathophysiological mechanisms of NPRA in cardiovascular diseases.

Renal Natriuretic Peptide Receptor-C Deficiency Attenuates NaCl Cotransporter Activity in Angiotensin II-Induced Hypertension

Genome-wide association studies have identified that NPR-C (natriuretic peptide receptor-C) variants are associated with elevation of blood pressure. However, the mechanism underlying the relationship between NPR-C and blood pressure regulation remains elusive. Here, we investigate whether NPR-C regulates Ang II (angiotensin II)-induced hypertension through sodium transporters activity. Wild-type mice responded to continuous Ang II infusion with an increased renal NPR-C expression. Global NPR-C deficiency attenuated Ang II-induced increased blood pressure both in male and female mice associated with more diuretic and natriuretic responses to a saline challenge. Interestingly, Ang II increased both total and phosphorylation of NCC (NaCl cotransporter) abundance involving in activation of WNK4 (with-no-lysine kinase 4)/SPAK (Ste20-related proline/alanine-rich kinase) which was blunted by NPR-C deletion. NCC inhibitor, hydrochlorothiazide, failed to induce natriuresis in NPR-C knockout mice. Moreover, low-salt and high-salt diets-induced changes of total and phosphorylation of NCC expression were normalized by NPR-C deletion. Importantly, tubule-specific deletion of NPR-C also attenuated Ang II-induced elevated blood pressure, total and phosphorylation of NCC expression. Mechanistically, in distal convoluted tubule cells, Ang II dose and time-dependently upregulated WNK4/SPAK/NCC kinase pathway and NPR-C/Gi/PLC/PKC signaling pathway mediated NCC activation. These results demonstrate that NPR-C signaling regulates NCC function contributing to sodium retention-mediated elevated blood pressure, which suggests that NPR-C is a promising candidate for the treatment of sodium retention-related hypertension.

Narrative review: the holy grail: update on pharmacotherapy for heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is the presence of clinical signs and/or symptoms of heart failure with a left ventricular ejection fraction (LVEF) ≥50%. Risk factors associated with this disease include hypertension, hyperlipidemia, atrial fibrillation (AF), obesity, diabetes and coronary artery disease (CAD). Despite the multiple risk factors identified for this condition, treatment and management remain challenging and a subject of ongoing research. Since a treatment approach that alters the natural course or lowers mortality for this disease has not been found, treating co-morbidities and symptom management is essential. From the comorbidities, hypertension is identified as the main risk factor for disease development. Thus, after congestive symptom control with diuretics, blood pressure (BP) management is considered one of the most important preventive measures and also a target for treatment. Amongst antihypertensives, angiotensin receptor blockers (ARBs) and aldosterone antagonists are the therapeutic agents used that have a role in reducing hospitalizations. Implantable monitoring devices have also been shown to reduce hospitalizations in comparison to standard heart failure therapies by allowing to tailor diuretic therapy based on ongoing hemodynamic data. In this manuscript we discuss pharmacologic strategies for HFpEF patients by risk factors, including those with and without a potential role.

Narrative review in the current role of angiotensin receptor-neprilysin inhibitors

Heart failure (HF) accounts for a tremendous burden on health care systems and the society. Since the landmark PARADIGM-HF trial, sacubitril/valsartan, the first in the class of angiotensin receptor neprilysin inhibitor (ARNI) showed superiority to enalapril in patients with HF with reduced ejection fraction (HFrEF). We performed a narrative literature review, hand-searched the reference lists of included articles and relevant reviews. Inhibition of neprilysin increases bradykinin, natriuretic peptides and adrenomedullin levels counteract the neurohormal activation that leads to sodium retention, vasoconstriction, and cardiac remodeling. In PARADIGM-HF the primary outcome of CV death or HF hospitalization was reduced 20% in the ARNI group (HR 0.80, P<0.001) similar to mortality due to cardiovascular cause (HR 0.80, P<0.001) in patients with HFrEF, rendering a number needed to treat of 21 patients. This effect was consistent across subgroups. The safety of starting ARNI inpatient once the acute decompensation of HF is stabilized was demonstrated in PIONEER-HF trial. With willingness-to-pay thresholds commonly acceptable in the United States, sacubitril/valsartan is likely to be cost effective, which might not be in other health systems. Although its safety has been reassured in some clinical trials, common side effects are hypotension, worsening kidney function, hyperkalemia and angioedema. In HFpEF (PARAGON-HF), sacubitril/valsartan showed decrease in the level of the cardiac biomarkers, with improve functional NYHA and decrease in hospitalizations, predominately in women and patients with borderline ejection fraction. Some ongoing studies aim to demonstrate the effects of ARNI in acute coronary syndrome, stable ischemic heart disease, advanced HF, mitral regurgitation, aortic impedance and pulmonary hypertension. In conclusion, sacubitril/valsartan has proven to be an effective addition to the HFrEF arsenal, with safety comparable to current standard of care. In HFpEF, it improves quality of life, particularly in women and in patients with borderline ejection fraction, with no effect on mortality.

The Effect of Sacubitril-Valsartan in Heart Failure Patients With Mid-Range and Preserved Ejection Fraction: A Meta-Analysis

BACKGROUND

The effect of sacubitril-valsartan in heart failure patients with mid-range (HFmEF) and preserved (HFpEF) ejection fractions remains unclear. This study aimed to investigate the clinical benefits of sacubitril-valsartan in HFmEF and HFpEF patients.

METHODS

PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure were searched from inception to 29 February 2020 to identify pertinent articles. Studies meeting the inclusion criteria were included and analysed.

RESULTS

Six (6) studies, with a total of 5,503 patients, were included. Compared with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, sacubitril-valsartan significantly reduced the rate of HF hospitalisation (risk ratios, 0.84; 95% CI, 0.77-0.91; p<0.001) and improved the New York Heart Association class (risk ratios, 1.25; 95% CI, 1.10-1.43; p=0.001) in HFmEF and HFpEF patients. Both the cardiovascular mortality and all-cause mortality were not significantly decreased by sacubitril-valsartan. In addition, there were no significant between-group differences in the N-terminal pro-B-type natriuretic peptide and left ventricular ejection fraction changes. Regarding safety, sacubitril-valsartan was likely to increase the risk of hypotension, but the incidence of serum creatinine elevation was significantly lower in the sacubitril-valsartan group than in the angiotensin-converting enzyme inhibitors and angiotensin receptor blockers group.

CONCLUSIONS

This meta-analysis suggests that sacubitril-valsartan may be an effective and safe strategy with which to improve the clinical symptoms and reduce HF hospitalisation in HFmEF and HFpEF patients.

Gaining insight into cellular cardiac physiology using single particle tracking

Single particle tracking (SPT) is a robust technique to monitor single-molecule behaviors in living cells directly. By this approach, we can uncover the potential biological significance of particle dynamics by statistically characterizing individual molecular behaviors. SPT provides valuable information at the single-molecule level, that could be obscured by simple averaging that is inherent to conventional ensemble measurements. Here, we give a brief introduction to SPT including the commonly used optical implementations, fluorescence labeling strategies, and data analysis methods. We then focus on how SPT has been harnessed to decipher myocardial function. In this context, SPT has provided novel insight into the lateral diffusion of signal receptors and ion channels, the dynamic organization of cardiac nanodomains, subunit composition and stoichiometry of cardiac ion channels, myosin movement along actin filaments, the kinetic features of transcription factors involved in cardiac remodeling, and the intercellular communication by nanotubes. Finally, we speculate on the prospects and challenges of applying SPT to future questions regarding cellular cardiac physiology using SPT.

Identification of Long Noncoding RNA H19 as a New Biomarker and Therapeutic Target in Right Ventricular Failure in Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular (RV) function is the major determinant for both functional capacity and survival in patients with pulmonary arterial hypertension (PAH). Despite the recognized clinical importance of preserving RV function, the subcellular mechanisms that govern the transition from a compensated to a decompensated state remain poorly understood and as a consequence there are no clinically established treatments for RV failure and a paucity of clinically useful biomarkers. Accumulating evidence indicates that long noncoding RNAs are powerful regulators of cardiac development and disease. Nonetheless, their implication in adverse RV remodeling in PAH is unknown.

METHODS

Expression of the long noncoding RNA H19 was assessed by quantitative PCR in plasma and RV from patients categorized as control RV, compensated RV or decompensated RV based on clinical history and cardiac index. The impact of H19 suppression using GapmeR was explored in 2 rat models mimicking RV failure, namely the monocrotaline and pulmonary artery banding. Echocardiographic, hemodynamic, histological, and biochemical analyses were conducted. In vitro gain- and loss-of-function experiments were performed in rat cardiomyocytes.

RESULTS

We demonstrated that H19 is upregulated in decompensated RV from PAH patients and correlates with RV hypertrophy and fibrosis. Similar findings were observed in monocrotaline and pulmonary artery banding rats. We found that silencing H19 limits pathological RV hypertrophy, fibrosis and capillary rarefaction, thus preserving RV function in monocrotaline and pulmonary artery banding rats without affecting pulmonary vascular remodeling. This cardioprotective effect was accompanied by E2F transcription factor 1-mediated upregulation of enhancer of zeste homolog 2. In vitro, knockdown of H19 suppressed cardiomyocyte hypertrophy induced by phenylephrine, while its overexpression has the opposite effect. Finally, we demonstrated that circulating H19 levels in plasma discriminate PAH patients from controls, correlate with RV function and predict long-term survival in 2 independent idiopathic PAH cohorts. Moreover, H19 levels delineate subgroups of patients with differentiated prognosis when combined with the NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels or the risk score proposed by both REVEAL (Registry to Evaluate Early and Long-Term PAH Disease Management) and the 2015 European Pulmonary Hypertension Guidelines.

CONCLUSIONS

Our findings identify H19 as a new therapeutic target to impede the development of maladaptive RV remodeling and a promising biomarker of PAH severity and prognosis.

Modelling the Impact of Chronic Cigarette Smoke Exposure in Obese Mice: Metabolic, Pulmonary, Intestinal, and Cardiac Issues

Unhealthy lifestyle choices, such as bad eating behaviors and cigarette smoking, have major detrimental impacts on health. However, the inter-relations between obesity and smoking are still not fully understood. We thus developed an experimental model of high-fat diet-fed obese C57BL/6 male mice chronically exposed to cigarette smoke. Our study evaluated for the first time the resulting effects of the combined exposure to unhealthy diet and cigarette smoke on several metabolic, pulmonary, intestinal, and cardiac parameters. We showed that the chronic exposure to cigarette smoke modified the pattern of body fat distribution in favor of the visceral depots in obese mice, impaired the respiratory function, triggered pulmonary inflammation and emphysema, and was associated with gut microbiota dysbiosis, cardiac hypertrophy and myocardial fibrosis.

Design of the SILICOFCM study: Effect of sacubitril/valsartan vs lifestyle intervention on functional capacity in patients with hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease with a broad spectrum of disease severity. HCM ranges from a benign course to a progressive disorder characterized by angina, heart failure, malignant arrhythmia, syncope, or sudden cardiac death. So far, no medical treatment has reliably shown to halt or reverse progression of HCM or to alleviate its symptoms. While the angiotensin receptor neprilysin inhibitor sacubitril/valsartan has shown to reduce mortality and hospitalization in heart failure with reduced ejection fraction, data on its effect on HCM are sparse.

Hypothesis

A 4‐month pharmacological (sacubitril/valsartan) or lifestyle intervention will significantly improve exercise tolerance (ie, peak oxygen consumption) in patients with nonobstructive HCM compared to the optimal standard therapy (control group).

Methods

SILICOFCM is a prospective, multicenter, open‐label, randomized, controlled, three‐arm clinical trial (NCT03832660) that will recruit 240 adult patients with a confirmed diagnosis of nonobstructive HCM. Eligible patients are randomized to sacubitril/valsartan, lifestyle intervention (physical activity and dietary supplementation with inorganic nitrate), or optimal standard therapy alone (control group). The primary endpoint is the change in functional capacity (ie, peak oxygen consumption). Secondary endpoints include: (a) Change in cardiac structure and function as assessed by transthoracic echocardiography and cardiac magnetic resonance (MRI imaging), (b) change in biomarkers (ie, CK, CKMB, and NT‐proBNP), (c) physical activity, and (d) quality of life.

Results

Until December 2019, a total of 41 patients were recruited into the ongoing SILICOFCM study and were allocated to the study groups and the control group. There was no significant difference in key baseline characteristics between the three groups.

Conclusion

The SILICOFCM study will provide novel evidence about the effect of sacubitril/valsartan or lifestyle intervention on functional capacity, clinical phenotype, injury and stretch activation markers, physical activity, and quality of life in patients with nonobstructive HCM.

Impact of renin-angiotensin-aldosterone system activation and body weight change on N-terminal pro-B-type natriuretic peptide variation in 100-km ultramarathon runners

BACKGROUND

The change in N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels follows a paradox imposed by strenuous endurance exercise. Previous reports showed significant body weight (BW) loss was common in ultramarathon runners. This study investigated whether the BW change and renin-angiotensin-aldosterone system activation contribute to exercise-induced NT-proBNP release.

METHODS

A total of 26 participants who finished a 100 km ultramarathon in Taiwan were enrolled. For each participant, blood samples and spot urine samples were collected 1 week before the race, as well as immediately and 24 hours after the finish. BW change was recorded to monitor the hydration status.

RESULTS

Prolonged endurance exercise led to a substantial increase in NT-proBNP. Compared with prerace values, NT-proBNP levels significantly increased immediately after the race (24.3 ± 20.2 pg/mL to 402.9 ± 305.9 pg/mL, p < 0.05) and maintained high levels until 24 hours after the race (143.7 ± 126.1 pg/mL, p < 0.05). The fractional excretion of sodium values was below 1% in three different time points. The 100 km ultramarathon resulted in significant BW loss and elevated renin and aldosterone levels. However, only 24 hours after the race, a positive significant relationship was found between NT-proBNP and aldosterone levels (p = 0.007, r = 0.267), but a negative significant relationship between NT-proBNP and BW increased during the recovery phase (p < 0.001, r = 0.372).

CONCLUSION

The mechanism of NT-proBNP release immediately following the race was multifaceted. During the recovery phase, rehydration might lead to the decrease of NT-proBNP. Our observations with regard to aldosterone and NT-proBNP might be in response to help the body maintains hydration state.

The Effects of Sacubitril/Valsartan on Clinical, Biochemical and Echocardiographic Parameters in Patients with Heart Failure with Reduced Ejection Fraction: The "Hemodynamic Recovery"

BACKGROUND

Sacubitril/valsartan has been shown to be superior to enalapril in reducing the risks of death and hospitalization for heart failure (HF). However, knowledge of the impact on cardiac performance remains limited. We sought to evaluate the effects of sacubitril/valsartan on clinical, biochemical and echocardiographic parameters in patients with heart failure and reduced ejection fraction (HFrEF).

METHODS

Sacubitril/valsartan was administered to 205 HFrEF patients.

RESULTS

Among 230 patients (mean age 59 ± 10 years, 46% with ischemic heart disease) 205 (89%) completed the study. After a follow-up of 10.49 (2.93 ± 18.44) months, the percentage of patients in New York Heart Association (NYHA) class III changed from 40% to 17% (p < 0.001). Median N-Type natriuretic peptide (Nt-proBNP) decreased from 1865 ± 2318 to 1514 ± 2205 pg/mL, (p = 0.01). Furosemide dose reduced from 131.3 ± 154.5 to 120 ± 142.5 (p = 0.047). Ejection fraction (from 27± 5.9% to 30 ± 7.7% (p < 0.001) and E/A ratio (from 1.67 ± 1.21 to 1.42 ± 1.12 (p = 0.002)) improved. Moderate to severe mitral regurgitation (from 30.1% to 17.4%; p = 0.002) and tricuspid velocity decreased from 2.8 ± 0.55 m/sec to 2.64 ± 0.59 m/sec (p < 0.014).

CONCLUSIONS

Sacubitril/valsartan induce "hemodynamic recovery" and, consistently with reduction in Nt-proBNP concentrations, improve NYHA class despite diuretic dose reduction.

NT-proBNP, race and endothelial function in the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Natriuretic peptides (NPs) are hormones with cardioprotective effects. NP levels vary by race; however, the pathophysiological consequences of lower NP levels are not well understood. We aimed to quantify the association between NPs and endothelial function as measured by flow-mediated dilation (FMD) and the contribution of NP levels to racial differences in endothelial function.

METHODS

In this cross-sectional study of 2938 Multi-Ethnic Study of Atherosclerosis participants (34% Caucasian, 20% African-American, 20% Asian-American and 26% Hispanic) without cardiovascular disease at baseline, multivariable linear regression models were used to examine the association between serum N-terminal pro-B-type NP (NT-proBNP) and natural log-transformed FMD. We also tested whether NT-proBNP mediated the relationship between race and FMD using the product of coefficients method.

RESULTS

Among African-American and Chinese-American individuals, lower NT-proBNP levels were associated with lower FMD, β=0.06 (95% CI: 0.03 to 0.09; p<0.001) and β=0.06 (95% CI: 0.02 to 0.09; p=0.002), respectively. Non-significant associations between NT-proBNP and FMD were found in Hispanic and Caucasian individuals. In multivariable models, endothelial function differed by race, with African-American individuals having the lowest FMD compared with Caucasians, p<0.001. Racial differences in FMD among African-Americans and Chinese-Americans were mediated in part by NT-proBNP levels (African-Americans, mediation effect: -0.03(95% CI: -0.05 to -0.01); Chinese-Americans, mediation effect: -0.03(95% CI: -0.05 to -0.01)).

CONCLUSIONS

Lower NP levels are associated with worse endothelial function among African-Americans and Chinese-Americans. A relative NP deficiency in some racial/ethnic groups may contribute to differences in vascular function.

Procholecystokinin expression and processing in cardiac myocytes

The mammalian heart is by now an established endocrine organ whose myocytes in a regulated manner release atrial and ventricular natriuretic peptides (ANP and BNP). But like other hormone-producing cells in classic endocrine organs, the cardiac myocytes also express genes of additional peptide hormones. One such hormone gene is that of the well-known pleiotropic gut-brain peptide system, cholecystokinin (CCK), which is expressed at mRNA and protein levels in both atrial and ventricular cardiac myocytes. The posttranslational processing of proCCK in the myocytes, however, deviates substantially from that of other CCK-producing cells. Hence, the predominant cardiac proCCK product is devoid of the N-terminal 1-24 fragment, and besides O-sulfated at three C-terminal tyrosyl residues (Y₇₆, Y₉₀, and Y₉₂). Moreover, carboxyamidated CCK peptides are present only in very low trace amounts (≤0.1%) in comparison with the truncated and triple-sulfated proCCK fragment. The present review first summarizes present knowledge about the wide-spread expression of the CCK system in mammals, and then discusses the possible function and biomarker role of the specific cardiac proCCK variant. The review concludes that the many unsettled questions about the specific cardiac expression cascade as well as the functional and diagnostic roles of cardiac CCK are worth pursuing.

Sacubitril/valsartan therapeutic strategy in HFpEF: Clinical insights and perspectives

Sacubitril/valsartan represents the first of a new class of drugs able to act as a neprilysin inhibitor and as an angiotensin receptor blocker. This double inhibition has the advantage of concomitantly blocking a pro-fibrotic/pro-hypertrophic mechanism (angiotensin receptor blocker component) while stimulating an anti-fibrotic/anti-hypertrophic mechanism (neprilysin inhibitor component). Furthermore, the novel drug has natriuretic and diuretic properties, better preserves renal function, provides better blood pressure control as compared to renin angiotensin system inhibitors, and improves ventricular-arterial coupling. Consequently, sacubitril/valsartan provides greater target organ protection than angiotensin receptor blocker therapy alone, including cardiac, vascular, and renal protection. Up to now, this drug does not have an indication in patients with heart failure with preserved ejection fraction (HFpEF). However, its complex mechanism of action and previous experimental and clinical data seem to suggest its possible success in HFpEF. In this review we highlight and discuss the rationale, clinical insights, and perspectives behind the use of sacubitril/valsartan in HFpEF, specifically referring to its possible efficacy in pathophysiologic mechanisms, such as myocardial hypertrophy, fibrosis, and ischemia, renal dysfunction, impaired ventricular-arterial coupling, which are all tightly related to elevated left ventricular end diastolic pressure, a common hallmark for this multifaceted syndrome.

Pharmacodynamic interaction between intravenous nitroglycerin and oral sacubitril/valsartan (LCZ696) in healthy subjects

PURPOSE

Sacubitril/valsartan (LCZ696) and nitroglycerin share the second messenger cGMP and lower blood pressure. Given the potential for co-administration of both drugs in patients with heart failure, this study was designed to investigate the potential for a pharmacodynamic drug interaction affecting blood pressure.

METHODS

In this double-blind, placebo-controlled, randomised, crossover study, 40 healthy subjects received sacubitril/valsartan 200 mg bid (97/103 mg bid) or placebo for 5 days. Two hours after the morning dose of sacubitril/valsartan or placebo on day 5, subjects received intravenous nitroglycerin infusion at increasing doses up to 40 μg/min or placebo. Serial measurements of blood pressure (BP), heart rate, biomarkers and sacubitril/valsartan pharmacokinetics were conducted.

RESULTS

Administration of nitroglycerin alone led to a dose- and time-dependent decrease in supine systolic BP (SBP) and diastolic BP (DBP) which was similar when nitroglycerin was co-administered with sacubitril/valsartan. At the highest dose of nitroglycerin, the mean (95% CI) decrease from baseline of SBP/DBP was 19.54 (- 21.99, - 17.09)/12.38 (- 13.85, - 10.92) mmHg for nitroglycerin alone compared to 22.63 (- 25.06, - 20.21)/12.94 (- 14.38, - 11.49) mmHg when co-administered with sacubitril/valsartan. Co-administration of sacubitril/valsartan and nitroglycerin did not result in further plasma cGMP increase compared to sacubitril/valsartan alone. The co-administration of nitroglycerin and sacubitril/valsartan was safe and well tolerated and did not impact the pharmacokinetics of sacubitril/valsartan.

CONCLUSIONS

The results from this study demonstrate no pharmacodynamic drug interaction between nitroglycerin and sacubitril/valsartan in healthy subjects, suggesting that no change of dose selection and escalation recommendations or clinical monitoring during nitroglycerin administration is required.

Epigenetic Programming of Synthesis, Release, and/or Receptor Expression of Common Mediators Participating in the Risk/Resilience for Comorbid Stress-Related Disorders and Coronary Artery Disease

Corticotrophin releasing factor, vasopressin, oxytocin, natriuretic hormones, angiotensin, neuregulins, some purinergic substances, and some cytokines contribute to the long-term modulation and restructuring of cardiovascular regulation networks and, at the same time, have relevance in situations of comorbid abnormal stress responses. The synthesis, release, and receptor expression of these mediators seem to be under epigenetic control since early stages of life, possibly underlying the comorbidity to coronary artery disease (CAD) and stress-related disorders (SRD). The exposure to environmental conditions, such as stress, during critical periods in early life may cause epigenetic programming modifying the development of pathways that lead to stable and long-lasting alterations in the functioning of these mediators during adulthood, determining the risk of or resilience to CAD and SRD. However, in contrast to genetic information, epigenetic marks may be dynamically altered throughout the lifespan. Therefore, epigenetics may be reprogrammed if the individual accepts the challenge to undertake changes in their lifestyle. Alternatively, epigenetics may remain fixed and/or even be inherited in the next generation. In this paper, we analyze some of the common neuroendocrine functions of these mediators in CAD and SRD and summarize the evidence indicating that they are under early programming to put forward the theoretical hypothesis that the comorbidity of these diseases might be epigenetically programmed and modified over the lifespan of the individual.

Natriuretic peptides promote glucose uptake in a cGMP-dependent manner in human adipocytes

Robust associations between low plasma level of natriuretic peptides (NP) and increased risk of type 2 diabetes (T2D) have been recently reported in humans. Adipose tissue (AT) is a known target of NP. However it is unknown whether NP signalling in human AT relates to insulin sensitivity and modulates glucose metabolism. We here show in two European cohorts that the NP receptor guanylyl cyclase-A (GC-A) expression in subcutaneous AT was down-regulated as a function of obesity grade while adipose NP clearance receptor (NPRC) was up-regulated. Adipose GC-A mRNA level was down-regulated in prediabetes and T2D, and negatively correlated with HOMA-IR and fasting blood glucose. We show for the first time that NP promote glucose uptake in a dose-dependent manner. This effect is reduced in adipocytes of obese individuals. NP activate mammalian target of rapamycin complex 1/2 (mTORC1/2) and Akt signalling. These effects were totally abrogated by inhibition of cGMP-dependent protein kinase and mTORC1/2 by rapamycin. We further show that NP treatment favoured glucose oxidation and de novo lipogenesis independently of significant gene regulation. Collectively, our data support a role for NP in blood glucose control and insulin sensitivity by increasing glucose uptake in human adipocytes. This effect is partly blunted in obesity.

Natriuretic peptides in the control of lipid metabolism and insulin sensitivity

Natriuretic peptides have long been known for their cardiovascular function. However, a growing body of evidence emphasizes the role of natriuretic peptides in human substrate and energy metabolism, thereby connecting the heart with several insulin-sensitive organs like adipose tissue, skeletal muscle and liver. Obesity may be associated with an impaired regulation of the natriuretic peptide system, also indicated as a natriuretic handicap. Evidence points towards a contribution of this natriuretic handicap to the development of obesity, type 2 diabetes mellitus and cardiometabolic complications, although the causal relationship is not fully understood. Nevertheless, targeting the natriuretic peptide pathway may improve metabolic health in obesity and type 2 diabetes mellitus. This review will focus on current literature regarding the metabolic roles of natriuretic peptides with emphasis on lipid metabolism and insulin sensitivity. Furthermore, it will be discussed how exercise and lifestyle intervention may modulate the natriuretic peptide-related metabolic effects.

Natriuretic Peptides: The Case of Prostate Cancer

Cardiac natriuretic peptides have long been known to act as main players in the homeostatic control of blood pressure, salt and water balance. However, in the last few decades, new properties have been ascribed to these hormones. A systematic review of English articles using MEDLINE Search terms included prostate cancer, inflammation, cardiac hormones, atrial natriuretic peptide, and brain natriuretic peptide. Most recent publications were selected. Natriuretic peptides are strongly connected to the immune system, whose two branches, innate and adaptive, are finely tuned and organized to kill invaders and repair injured tissues. These peptides control the immune response and act as anti-inflammatory and immune-modulatory agents. In addition, in cancers, natriuretic peptides have anti-proliferative effects by molecular mechanisms based on the inhibition/regulation of several pathways promoting cell proliferation and survival. Nowadays, it is accepted that chronic inflammation is a crucial player in prostate cancer development and progression. In this review, we summarize the current knowledge on the link between prostate cancer and inflammation and the potential use of natriuretic peptides as anti-inflammatory and anticancer agents.

The multifaceted role of natriuretic peptides in metabolic syndrome

Due to globalization and sophisticated western and sedentary lifestyle, metabolic syndrome has emerged as a serious public health challenge. Obesity is significantly increasing worldwide because of increased high calorie food intake and decreased physical activity leading to hypertension, dyslipidemia, atherosclerosis, and insulin resistance. Thus, metabolic syndrome constitutes cardiovascular disease, type 2 diabetes, obesity, and nonalcoholic fatty liver disease (NAFLD) and recently some cancers are also considered to be associated with this syndrome. There is increasing evidence of the involvement of natriuretic peptides (NP) in the pathophysiology of metabolic diseases. The natriuretic peptides are cardiac hormones, which are produced in the cardiac atrium, ventricles of the heart and the endothelium. These peptides are involved in the homeostatic control of body water, sodium intake, potassium transport, lipolysis in adipocytes and regulates blood pressure. The three known natriuretic peptide hormones present in the natriuretic system are atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and c-type natriuretic peptide (CNP). These three peptides primarily function as endogenous ligands and mainly act via their membrane receptors such as natriuretic peptide receptor A (NPR-A), natriuretic peptide receptor B (NPR-B) and natriuretic peptide receptor C (NPR-C) and regulate various physiological and metabolic functions. This review will shed light on the structure and function of natriuretic peptides and their receptors and their role in the metabolic syndrome.

Focus on the Novel Cardiovascular Drug LZC696: from Evidence to Clinical Consideration

LCZ696, a first-in-class angiotensin receptor neprilysin inhibitor (ARNI), is comprised of the angiotensin receptor blocker valsartan and the neprilysin inhibitor pro-drug sacubitril (AHU377). After oral administration, AHU377 is rapidly metabolized to the active neprilysin inhibitor LBQ657. LCZ696 exerts its effects of diuresis, natriuresis, vasodilation and aldosterone secretion inhibition through simultaneous renin-angiotensin-aldosterone system (RAAS) blockade and natriuretic peptides system (NPS) enhancement. Powerful evidence including PARAMETER and PRARDIGM-HF trials have shown that LCZ696 outperforms RAAS inhibition in treating patients with hypertension and heart failure with reduced ejection fraction (HFrEF), and is well tolerated. In addition, accumulating evidence also suggests its potential use in heart failure with preserved ejection fraction (HFpEF), chronic kidney disease (CKD), post-myocardium infarction (post-MI) and stroke. Both the FDA and CHMP have approved LCZ696 for treatment of HFrEF. Despite all this, some special issues (e.g. use in specific subgroups, adverse events, contraindications and cost-effectiveness analysis) should be considered before its implementation in clinical practice.

Amplification of lipotoxic cardiomyopathy in the VDR gene knockout mouse

Previous studies demonstrated that the liganded vitamin D receptor (VDR) plays an important role in controlling cardiovascular homeostasis. Both the whole animal VDR gene knockout (VDR^-/-) and the myocyte-specific VDR gene deletion result in changes in cardiac structure and function. Clinical states associated with cardiac steatosis (obesity and diabetes mellitus) are also associated with low circulating 25 OH vitamin D levels. We, therefore, examined the effects of VDR deficiency (VDR^-/- mouse) in a murine model of cardiac steatosis that expresses the terminal enzyme involved in triglyceride synthesis, diacylglycerol acyltransferase 1 (DGAT1), selectively in the cardiac myocyte. These mice display early cardiac dysfunction and late cardiomyopathy and heart failure. In the present study, we demonstrate that mice harboring both genetic modifications (i.e., MHC-DGAT1 Tg and VDR^-/-) exhibit an increase in myocyte size, heart weight/body weight ratio and natriuretic peptide gene expression, all markers of cardiac hypertrophy, that exceed that seen in either VDR^-/- or the MHC-DGAT1 Tg mice alone. This was accompanied by a dramatic increase in interstitial fibrosis and increased expression of collagen 1a1 and collagen 3a1, as well as the osteopontin and matrix metalloproteinase 2, genes. At a functional level, this resulted in a 37% reduction in ejection fraction and 55% reduction in fractional shortening in the DGAT1; VDR^-/- mice relative to the controls. Collectively, these data demonstrate that deficiency in the vitamin D signaling system enhances the pathological phenotype in this experimental cardiomyopathy and suggest an important role for vitamin D in modulating disease severity in common cardiovascular disorders.

Molecular Physiology of Membrane Guanylyl Cyclase Receptors

cGMP controls many cellular functions ranging from growth, viability, and differentiation to contractility, secretion, and ion transport. The mammalian genome encodes seven transmembrane guanylyl cyclases (GCs), GC-A to GC-G, which mainly modulate submembrane cGMP microdomains. These GCs share a unique topology comprising an extracellular domain, a short transmembrane region, and an intracellular COOH-terminal catalytic (cGMP synthesizing) region. GC-A mediates the endocrine effects of atrial and B-type natriuretic peptides regulating arterial blood pressure/volume and energy balance. GC-B is activated by C-type natriuretic peptide, stimulating endochondral ossification in autocrine way. GC-C mediates the paracrine effects of guanylins on intestinal ion transport and epithelial turnover. GC-E and GC-F are expressed in photoreceptor cells of the retina, and their activation by intracellular Ca(2+)-regulated proteins is essential for vision. Finally, in the rodent system two olfactorial GCs, GC-D and GC-G, are activated by low concentrations of CO2and by peptidergic (guanylins) and nonpeptidergic odorants as well as by coolness, which has implications for social behaviors. In the past years advances in human and mouse genetics as well as the development of sensitive biosensors monitoring the spatiotemporal dynamics of cGMP in living cells have provided novel relevant information about this receptor family. This increased our understanding of the mechanisms of signal transduction, regulation, and (dys)function of the membrane GCs, clarified their relevance for genetic and acquired diseases and, importantly, has revealed novel targets for therapies. The present review aims to illustrate these different features of membrane GCs and the main open questions in this field.

Diagnostic and therapeutic problems of isolated systolic hypertension

Prevalence of isolated systolic hypertension increases with age, due to progressive elevation of SBP, and is a major risk factor for cardiovascular morbidity and mortality. Extensive research has shown that lowering SBP improves cardiovascular outcomes in patients with isolated systolic hypertension, yet SBP control rates remain largely inadequate regardless of antihypertensive treatment. Arterial stiffness is a major determinant of elevated SBP resulting from structural changes in the vascular system, mediated by neurohormonal alterations that occur with vascular ageing. Clinical data have demonstrated an independent association between arterial stiffness and cardiovascular outcomes. Therefore, arterial stiffness has the potential to be an important therapeutic target in the management of isolated systolic hypertension. Current antihypertensive treatments have limited effects on arterial stiffness, so the development of new treatments addressing neurohormonal alterations central to vascular ageing is important. Such therapies may represent effective strategies in the future management of SBP.