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

NeuroPep 2.0: An Updated Database Dedicated to Neuropeptide and Its Receptor Annotations

Neuropeptides not only work through nervous system but some of them also work peripherally to regulate numerous physiological processes. They are important in regulation of numerous physiological processes including growth, reproduction, social behavior, inflammation, fluid homeostasis, cardiovascular function, and energy homeostasis. The various roles of neuropeptides make them promising candidates for prospective therapeutics of different diseases. Currently, NeuroPep has been updated to version 2.0, it now holds 11,417 unique neuropeptide entries, which is nearly double of the first version of NeuroPep. When available, we collected information about the receptor for each neuropeptide entry and predicted the 3D structures of those neuropeptides without known experimental structure using AlphaFold2 or APPTEST according to the peptide sequence length. In addition, DeepNeuropePred and NeuroPred-PLM, two neuropeptide prediction tools developed by us recently, were also integrated into NeuroPep 2.0 to help to facilitate the identification of new neuropeptides. NeuroPep 2.0 is freely accessible at https://isyslab.info/NeuroPepV2/.

Snake Venom Components as Therapeutic Drugs in Ischemic Heart Disease

Ischemic heart disease (IHD), especially myocardial infarction (MI), is a leading cause of death worldwide. Although coronary reperfusion is the most straightforward treatment for limiting the MI size, it has nevertheless been shown to exacerbate ischemic myocardial injury. Therefore, identifying and developing therapeutic strategies to treat IHD is a major medical challenge. Snake venoms contain biologically active proteins and peptides that are of major interest for pharmacological applications in the cardiovascular system (CVS). This has led to their use for the development and design of new drugs, such as the first-in-class angiotensin-converting enzyme inhibitor captopril, developed from a peptide present in Bothrops jararaca snake venom. This review discusses the potential usefulness of snake venom toxins for developing effective treatments against IHD and related diseases such as hypertension and atherosclerosis. It describes their biological effects at the molecular scale, their mechanisms of action according to their different pharmacological properties, as well as their subsequent molecular pathways and therapeutic targets. The molecules reported here have either been approved for human medical use and are currently available on the drug market or are still in the clinical or preclinical developmental stages. The information summarized here may be useful in providing insights into the development of future snake venom-derived drugs.

Urinary NT-proBNP: A Useful Biomarker for the Diagnosis of Respiratory Distress in the Neonatal Population

OBJECTIVE

To determine the diagnostic accuracy of urinary NT-proBNP levels in the detection and classification of the severity of respiratory distress in neonates after birth.

METHODS

We compared the urinary NT- proBNP levels between the respiratory distress (RD) group and the control group on the 1st, 3rd, and 5th day of life (DOL).

RESULTS

The RD group (55 neonates) showed higher levels of NT-proBNP compared to the control group (63 neonates) on DOL1 (585.4 pg/ml vs 396.1 pg/ml (p=0.014)), DOL3 (805.1 pg/ml vs 271.9 pg/ml (p<0.001)) and DOL5 (409.7 pg/ml vs 94.4 pg/ml (p<0.001)). Especially, on DOL5, the area under the ROC curve was 0.884 and the NT-proBNP cut-off value (221.8 pg/ml) showed a sensitivity of 71% and specificity of 79%. The RD group was subclassified into neonates with mild (21 neonates), moderate (19 neonates), and severe (15 neonates) disease. NT-proBNP cut-off point of 668 pg/ml for DOL5 can safely differentiate neonates with severe disease from those with mild and moderate disease (combined subgroups) since the sensitivity was 80% and specificity was 77.5% for DOL5.

CONCLUSION

Urinary NT-proBNP levels are a useful biomarker in detecting clinical signs of respiratory distress in neonates that are born within the first week of life; they can also detect neonates that are vulnerable to severe forms of the disease.

Atrial natriuretic peptide stimulates autophagy/mitophagy and improves mitochondrial function in chronic heart failure

Mitochondrial dysfunction, causing increased reactive oxygen species (ROS) production, is a molecular feature of heart failure (HF). A defective antioxidant response and mitophagic flux were reported in circulating leucocytes of patients with chronic HF and reduced ejection fraction (HFrEF). Atrial natriuretic peptide (ANP) exerts many cardiac beneficial effects, including the ability to protect cardiomyocytes by promoting autophagy. We tested the impact of ANP on autophagy/mitophagy, altered mitochondrial structure and function and increased oxidative stress in HFrEF patients by both ex vivo and in vivo approaches. The ex vivo study included thirteen HFrEF patients whose peripheral blood mononuclear cells (PBMCs) were isolated and treated with αANP (10^-11 M) for 4 h. The in vivo study included six HFrEF patients who received sacubitril/valsartan for two months. PBMCs were characterized before and after treatment. Both approaches analyzed mitochondrial structure and functionality. We found that levels of αANP increased upon sacubitril/valsartan, whereas levels of NT-proBNP decreased. Both the ex vivo direct exposure to αANP and the higher αANP level upon in vivo treatment with sacubitril/valsartan caused: (i) improvement of mitochondrial membrane potential; (ii) stimulation of the autophagic process; (iii) significant reduction of mitochondrial mass-index of mitophagy stimulation-and upregulation of mitophagy-related genes; (iv) reduction of mitochondrial damage with increased inner mitochondrial membrane (IMM)/outer mitochondrial membrane (OMM) index and reduced ROS generation. Herein we demonstrate that αANP stimulates both autophagy and mitophagy responses, counteracts mitochondrial dysfunction, and damages ultimately reducing mitochondrial oxidative stress generation in PBMCs from chronic HF patients. These properties were confirmed upon sacubitril/valsartan administration, a pivotal drug in HFrEF treatment.

NPPA/atrial natriuretic peptide is an extracellular modulator of autophagy in the heart

NPPA/atrial natriuretic peptide (natriuretic peptide type A) exerts critical pleiotropic effects in the cardiovascular system, limiting cardiomyocyte hypertrophy and death, reducing cardiac fibrosis and promoting vascular integrity. However, the molecular mechanisms underlying these beneficial effects still need to be clarified. We demonstrated for the first time that macroautophagy/autophagy is involved in the local protective effects of NPPA in cardiomyocytes (CMs), both in vitro and in vivo. Exogenous NPPA rapidly activates autophagy in CMs through NPR1/type A natriuretic peptide receptor and PRKG/protein kinase G signaling and also increases cardiac autophagy in mice. Remarkably, endogenous NPPA is secreted by CMs in response to glucose deprivation or hypoxia, thereby stimulating autophagy through autocrine/paracrine mechanisms. NPPA preserves cell viability and reduces hypertrophy in response to stress through autophagy activation. In vivo, we found that Nppa knockout mice undergoing ischemia-reperfusion (I/R) show increased infarct size and reduced autophagy. Reactivation of autophagy by Tat-Beclin D11 limits I/R injury. We also found that the protective effects of NPPA in reducing infarct size are abrogated in the presence of autophagy inhibition. Mechanistically, we found that NPPA stimulates autophagy through the activation of TFEB (transcription factor EB). Our data suggest that NPPA is a novel extracellular regulator of autophagy in the heart.

The Effects of Angiotensin Receptor-Neprilysin Inhibition on Major Coronary Events in Patients With Acute Myocardial Infarction: Insights From the PARADISE-MI Trial

BACKGROUND

In patients who survive an acute myocardial infarction (AMI), angiotensin-converting enzyme inhibitors decrease the risk of subsequent major cardiovascular events. Whether angiotensin-receptor blockade and neprilysin inhibition with sacubitril/valsartan reduce major coronary events more effectively than angiotensin-converting enzyme inhibitors in high-risk patients with recent AMI remains unknown. We aimed to compare the effects of sacubitril/valsartan on coronary outcomes in patients with AMI.

METHODS

We conducted a prespecified analysis of the PARADISE-MI trial (Prospective ARNI vs ACE Inhibitors Trial to Determine Superiority in Reducing Heart Failure Events After MI), which compared sacubitril/valsartan (97/103 mg twice daily) with ramipril (5 mg twice daily) for reducing heart failure events after myocardial infarction in 5661 patients with AMI complicated by left ventricular systolic dysfunction, pulmonary congestion, or both. In the present analysis, the prespecified composite coronary outcome was the first occurrence of death from coronary heart disease, nonfatal myocardial infarction, hospitalization for angina, or postrandomization coronary revascularization.

RESULTS

Patients were randomly assigned at a median of 4.4 [3.0-5.8] days after index AMI (ST-segment-elevation myocardial infarction 76%, non-ST-segment-elevation myocardial infarction 24%), by which time 89% of patients had undergone coronary reperfusion. Compared with ramipril, sacubitril/valsartan decreased the risk of coronary outcomes (hazard ratio, 0.86 [95% CI, 0.74-0.99], P=0.04) over a median follow-up of 22 months. Rates of the components of the composite outcomes were lower in patients on sacubitril/valsartan but were not individually significantly different.

CONCLUSIONS

In survivors of an AMI with left ventricular systolic dysfunction and pulmonary congestion, sacubitril/valsartan-compared with ramipril-reduced the risk of a prespecified major coronary composite outcome. Dedicated studies are necessary to confirm this finding and elucidate its mechanism.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02924727.

Role of Cardiac Natriuretic Peptides in Heart Structure and Function

Cardiac natriuretic peptides (NPs), atrial NP (ANP) and B-type NP (BNP) are true hormones produced and released by cardiomyocytes, exerting several systemic effects. Together with C-type NP (CNP), mainly expressed by endothelial cells, they also exert several paracrine and autocrine activities on the heart itself, contributing to cardiovascular (CV) health. In addition to their natriuretic, vasorelaxant, metabolic and antiproliferative systemic properties, NPs prevent cardiac hypertrophy, fibrosis, arrhythmias and cardiomyopathies, counteracting the development and progression of heart failure (HF). Moreover, recent studies revealed that a protein structurally similar to NPs mainly produced by skeletal muscles and osteoblasts called musclin/osteocrin is able to interact with the NPs clearance receptor, attenuating cardiac dysfunction and myocardial fibrosis and promoting heart protection during pathological overload. This narrative review is focused on the direct activities of this molecule family on the heart, reporting both experimental and human studies that are clinically relevant for physicians.

Effect of Sacubitril-Valsartan on Quality of Life, Functional and Exercise Capacity in Heart Failure with Preserved Ejection Fraction (HFpEF): A Systematic Review of Randomized Clinical Trials

Background: Sacubitril/Valsartan use in heart failure has shown promising results in early trials. However, the effects on the overall functional capacity, exercise capacity, and quality of life are unknown. Aims: We aimed to understand the results of studies that attempted to measure these outcomes that affect the mobility and day-to-day life of these patients. Methods: MEDLINE, PubMed, PubMed Central (PMC), Google Scholar, ClinicalTrials.gov, and ISRCTN were explored to look for clinical trials relevant to the literature. Results: A total of three high-quality randomized controlled trials were discovered that evaluated the effect of sacubitril-valsartan on functional capacity, exercise capacity, or quality of life. All of them were industry-funded and revealed no statistical difference in the mentioned outcomes. No study measured peak oxygen uptake or ventilation/carbon dioxide ratio slope. Conclusion: Sacubitril-valsartan had minimal to no impact on functional capacity, exercise capacity, or quality of life. However, future prospective studies with more sensitive outcome measures should be conducted to validate the findings.

Follistatin-like 1 and its paralogs in heart development and cardiovascular disease

Cardiovascular diseases (CVDs) are a group of disorders affecting the heart and blood vessels and a leading cause of death worldwide. Thus, there is a need to identify new cardiokines that may protect the heart from damage as reported in GBD 2017 Causes of Death Collaborators (2018) (The Lancet 392:1736-1788). Follistatin-like 1 (FSTL1) is a cardiokine that is highly expressed in the heart and released to the serum after cardiac injury where it is associated with CVD and predicts poor outcome. The action of FSTL1 likely depends not only on the tissue source but also post-translation modifications that are target tissue- and cell-specific. Animal studies examining the effect of FSTL1 in various models of heart disease have exploded over the past 15 years and primarily report a protective effect spanning from inhibiting inflammation via transforming growth factor, preventing remodeling and fibrosis to promoting angiogenesis and hypertrophy. A better understanding of FSTL1 and its homologs is needed to determine whether this protein could be a useful novel biomarker to predict poor outcome and death and whether it has therapeutic potential. The aim of this review is to provide a comprehensive description of the literature for this family of proteins in order to better understand their role in normal physiology and CVD.

Acyldepsipeptide Analogues: A Future Generation Antibiotics for Tuberculosis Treatment

Acyldepsipeptides (ADEPs) are a new class of emerging antimicrobial peptides (AMPs), which are currently explored for treatment of pathogenic infections, including tuberculosis (TB). These cyclic hydrophobic peptides have a unique bacterial target to the conventional anti-TB drugs, and present a therapeutic window to overcome Mycobacterium Tuberculosis (M. tb) drug resistance. ADEPs exerts their antibacterial activity on M. tb strains through activation of the protein homeostatic regulatory protease, the caseinolytic protease (ClpP1P2). ClpP1P2 is normally regulated and activated by the ClpP-ATPases to degrade misfolded and toxic peptides and/or short proteins. ADEPs bind and dysregulate all the homeostatic capabilities of ClpP1P2 while inducing non-selective proteolysis. The uncontrolled proteolysis leads to M. tb cell death within the host. ADEPs analogues that have been tested possess cytotoxicity and poor pharmacokinetic and pharmacodynamic properties. However, these can be improved by drug design techniques. Moreover, the use of nanomaterial in conjunction with ADEPs would yield effective synergistic effect. This new mode of action has potential to combat and eradicate the extensive multi-drug resistance (MDR) problem that is currently faced by the public health pertaining bacterial infections, especially TB.

Glucocorticoids Promote Na+ Excretion in the Renal Epithelia of Heart Failure Rats by Suppressing Transporter Proteins Involved in Acute Sodium Loading

ABSTRACT

Glucocorticoid receptors are essential for normal development and stress responses. Their role in H 2 O and Na + metabolism, especially in chronic heart failure (CHF), is not well defined. In a previous study, we found that glucocorticoids potentiate urination in CHF and promote H 2 O excretion by inhibiting the vasopressin receptor 2 pathway. The present study examines the effect of glucocorticoids on renal Na + excretion and the underlying mechanisms in CHF rats with acute sodium loading. CHF was induced by left coronary artery ligation for 8 weeks. Rats were randomly assigned to 5 groups: control, CHF, dexamethasone (DEX)-administered CHF, DEX-administered CHF treated with RU486 (mifepristone, a glucocorticoid receptor antagonist), and RU486-treated CHF. An acute sodium loading test was performed 6 hours after DEX administration. Blood and urine samples were collected, and hemodynamics were measured. The expression and localization of Na + transporter proteins were determined by immunoblotting and immunohistochemistry. DEX increased the urine volume and urinary sodium and improved cardiac function and the estimated glomerular filtration rate in CHF rats. The upregulation of the epithelial sodium channel β and γ subunits, Na-K-2Cl cotransporter, serum glucocorticoid-regulated kinase 1 (SGK1), and Na + /K + -ATPase in the renal epithelium of CHF rats was downregulated by DEX. These beneficial effects were abolished by RU486. The expression of natriuretic peptide receptor A was opposite that of the above proteins. Glucocorticoids might induce profound natriuresis in CHF rats during acute sodium loading, which is associated with downregulating some Na + transporter proteins in the renal epithelium and improving intrarenal hemodynamics.

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

Exogenous Bioactive Peptides Have a Potential Therapeutic Role in Delaying Aging in Rodent Models

In recent years, some exogenous bioactive peptides have been shown to have promising anti-aging effects. These exogenous peptides may have a mechanism similar to endogenous peptides, and some can even regulate the release of endogenous active peptides and play a synergistic role with endogenous active peptides. Most aging studies use rodents that are easy to maintain in the laboratory and have relatively homogenous genotypes. Moreover, many of the anti-aging studies using bioactive peptides in rodent models only focus on the activity of single endogenous or exogenous active peptides, while the regulatory effects of exogenous active peptides on endogenous active peptides remain largely under-investigated. Furthermore, the anti-aging activity studies only focus on the effects of these bioactive peptides in individual organs or systems. However, the pathological changes of one organ can usually lead to multi-organ complications. Some anti-aging bioactive peptides could be used for rescuing the multi-organ damage associated with aging. In this paper, we review recent reports on the anti-aging effects of bioactive peptides in rodents and summarize the mechanism of action for these peptides, as well as discuss the regulation of exogenous active peptides on endogenous active peptides.

A Contemporary View of Natriuretic Peptides in the SARS-CoV-2 Era

The heart releases natriuretic peptides (NPs) which represent an important hormonal axis with cardiorenal protective effects. In view of their properties, NPs have pathophysiologic, diagnostic and prognostic implications in several cardiovascular diseases (CVDs). Severe pulmonary inflammation, as induced by the SARS-COV2, may increase pulmonary pressure with potential influence on NPs release, whereby normal cardiovascular integrity becomes impaired. Moreover, pre-existing CVDs are strong negative prognostic factors since they exacerbate the effects of the viral infection and lead to worse outcomes. In this context, it may be expected that NPs exert a key protective role toward the virus infection whereas an impairment of NPs release contributes to the virus deleterious effects. In this review article we explore the potential involvement of NPs in the COVID-19 disease. To this aim, we will first focus on the interactions between NPs and the Ang II/ATIR arm of the renin-angiotensin-aldosterone system (RAAS) as well as with the protective ACE2/Ang (1-7) arm of the RAAS. Subsequently, we will review evidence that strongly supports the role of increased NT-proBNP level as a marker of cardiac damage and of worse prognosis in the COVID-19 affected patients. Finally, we will discuss the potential therapeutic benefits of these protective hormones toward the viral infection through their endothelial protective function, anti-inflammatory and anti-thrombotic effects. In conclusion, the potential implications of NPs in the SARS-CoV-2 infection, as discussed in our article, represent an important issue that deserves to be fully investigated.

Atrial Natriuretic Peptide31-67: A Novel Therapeutic Factor for Cardiovascular Diseases

The characterization of the cardiac hormone atrial natriuretic peptide (ANP_99–126), synthesized and secreted predominantly by atrial myocytes under stimulation by mechanical stretch, has established the heart as an endocrine organ with potent natriuretic, diuretic, and vasodilating actions. Three additional distinct polypeptides resulting from proteolytic cleavage of proANP have been identified in the circulation in humans. The mid-sequence proANP fragment 31–67 (also known as proANP_31–67) has unique potent and prolonged diuretic and natriuretic properties. In this review, we report the main effects of this circulating hormone in different tissues and organs, and its mechanisms of actions. We further highlight recent evidence on the cardiorenal protective actions of chronic supplementation of synthetic proANP_31–67 in preclinical models of cardiorenal disease. Finally, we evaluate the use of proANP_31–67 as a new therapeutic strategy to repair end-organ damage secondary to hypertension, diabetes mellitus, renal diseases, obesity, heart failure, and other morbidities that can lead to impaired cardiac function and structure.

Cardiac morphological and functional changes induced by C-type natriuretic peptide are different in normotensive and spontaneously hypertensive rats

OBJECTIVE

Inflammation and fibrosis are key mechanisms in cardiovascular remodeling. C-type natriuretic peptide (CNP) is an endothelium-derived factor with a cardiovascular protective role, although its in-vivo effect on cardiac remodeling linked to hypertension has not been investigated. The aim of this study was to determine the effects of chronic administration of CNP on inflammatory and fibrotic cardiac mechanisms in normotensive Wistar rats and spontaneously hypertensive rats (SHR).

METHODS

Twelve-week-old male SHR and normotensive rats were infused with CNP (0.75 μg/h/100 g) or isotonic saline (NaCl 0.9%) for 14 days (subcutaneous micro-osmotic pumps). Echocardiograms and electrocardiograms were performed, and SBP was measured. After treatment, transforming growth factor-beta 1, Smad proteins, tumor necrosis factor-alpha, interleukin-1 and interleukin-6, nitric oxide (NO) system and 2-thiobarbituric acid-reactive substances were evaluated in left ventricle. Histological studies were also performed.

RESULTS

SHR showed lower cardiac output with signs of fibrosis and hypertrophy in left ventricle, higher NO-system activity and more oxidative damage, as well as higher pro-inflammatory and pro-fibrotic markers than normotensive rats. Chronic CNP treatment-attenuated hypertension and ventricular hypertrophy in SHR, with no changes in normotensive rats. In left ventricle, CNP induced an anti-inflammatory and antifibrotic response, decreasing both pro-fibrotic and pro-inflammatory cytokines in SHR. In addition, CNP reduced oxidative damage as well as collagen content, and upregulated the NO system in both groups.

CONCLUSION

Chronic CNP treatment appears to attenuate hypertension and associated end-organ damage in the heart by reducing inflammation and fibrosis.

Snake Venom Components: Tools and Cures to Target Cardiovascular Diseases

Cardiovascular diseases (CVDs) are considered as a major cause of death worldwide. Therefore, identifying and developing therapeutic strategies to treat and reduce the prevalence of CVDs is a major medical challenge. Several drugs used for the treatment of CVDs, such as captopril, emerged from natural products, namely snake venoms. These venoms are complex mixtures of bioactive molecules, which, among other physiological networks, target the cardiovascular system, leading to them being considered in the development and design of new drugs. In this review, we describe some snake venom molecules targeting the cardiovascular system such as phospholipase A2 (PLA2), natriuretic peptides (NPs), bradykinin-potentiating peptides (BPPs), cysteine-rich secretory proteins (CRISPs), disintegrins, fibrinolytic enzymes, and three-finger toxins (3FTXs). In addition, their molecular targets, and mechanisms of action—vasorelaxation, inhibition of platelet aggregation, cardioprotective activities—are discussed. The dissection of their biological effects at the molecular scale give insights for the development of future snake venom-derived drugs.

The Role of Neprilysin Inhibitors in the Treatment of Heart Failure with Preserved Ejection Fraction

Clinical and hemodynamic aggravation of heart failure with preserved ejection fraction (HFpEF) is largely due to progression of left ventricular (LV) diastolic dysfunction. The key role in the normal maintenance of diastolic function is played by a high level of activity of the intracellular signaling axis, cyclic guanosine-monophosphate-protein kinase G, the activity of which is significantly reduced in HFpEF. The activity of this axis can be increased by increasing the bioavailability of natriuretic peptides by blocking the enzyme neutral endopeptidase (neprilisin), which is responsible for the destruction of natriuretic peptides.This review presents experimental and clinical data on the use of neprilysin inhibitors in HFpEF and addresses prospects of this treatment.

Epigenetic control of natriuretic peptides: implications for health and disease

The natriuretic peptides (NPs) family, including a class of hormones and their receptors, is largely known for its beneficial effects within the cardiovascular system to preserve regular functions and health. The concentration level of each component of the family is of crucial importance to guarantee a proper control of both systemic and local cardiovascular functions. A fine equilibrium between gene expression, protein secretion and clearance is needed to achieve the final optimal level of NPs. To this aim, the regulation of gene expression and translation plays a key role. In this regard, we know the existence of fine regulatory mechanisms, the so-called epigenetic mechanisms, which target many genes at either the promoter or the 3'UTR region to inhibit or activate their expression. The gene encoding ANP (NPPA) is regulated by histone modifications, DNA methylation, distinct microRNAs and a natural antisense transcript (NPPA-AS1) with consequent implications for both health and disease conditions. Notably, ANP modulates microRNAs on its own. Histone modifications of BNP gene (NPPB) are associated with several cardiomyopathies. The proBNP processing is regulated by miR30-GALNT1/2 axis. Among other components of the NPs family, CORIN, NPRA, NPRC and NEP may undergo epigenetic regulation. A better understanding of the epigenetic control of the NPs family will allow to gain more insights on the pathological basis of common cardiovascular diseases and to identify novel therapeutic targets. The present review article aims to discuss the major achievements obtained so far with studies on the epigenetic modulation of the NPs family.

Range of adiposity and cardiorenal syndrome

Obesity and obesity-related co-morbidities, diabetes mellitus, and hypertension are among the fastest-growing risk factors of heart failure and kidney disease worldwide. Obesity, which is not a unitary concept, or a static process, ranges from alterations in distribution to the amount of adiposity. Visceral adiposity, which includes intraabdominal visceral fat mass and ectopic fat deposition such as hepatic, cardiac, or renal, was robustly associated with a greater risk for cardiorenal morbidity than subcutaneous adiposity. In addition, morbid obesity has also demonstrated a negative effect on cardiac and renal functioning. The mechanisms by which adipose tissue is linked with the cardiorenal syndrome (CRS) are hemodynamic and mechanical changes, as well neurohumoral pathways such as insulin resistance, endothelial dysfunction, nitric oxide bioavailability, renin-angiotensin-aldosterone, oxidative stress, sympathetic nervous systems, natriuretic peptides, adipokines and inflammation. Adiposity and other associated co-morbidities induce adverse cardiac remodeling and interstitial fibrosis. Heart failure with preserved ejection fraction has been associated with obesity-related functional and structural abnormalities. Obesity might also impair kidney function through hyperfiltration, increased glomerular capillary wall tension, and podocyte dysfunction, which leads to tubulointerstitial fibrosis and loss of nephrons and, finally, chronic kidney disease. The development of new treatments with renal and cardiac effects in the context of type 2 diabetes, which improves mortality outcome, has highlighted the importance of CRS and its prevalence. Increased body fat triggers cellular, neuro-humoral and metabolic pathways, which create a phenotype of the CRS with specific cellular and biochemical biomarkers. Obesity has become a single cardiorenal umbrella or type of cardiorenal metabolic syndrome. This review article provides a clinical overview of the available data on the relationship between a range of adiposity and CRS, the support for obesity as a single cardiorenal umbrella, and the most relevant studies on the recent therapeutic approaches.

Cardiac natriuretic peptides

Investigations into the mixed muscle-secretory phenotype of cardiomyocytes from the atrial appendages of the heart led to the discovery that these cells produce, in a regulated manner, two polypeptide hormones - the natriuretic peptides - referred to as atrial natriuretic factor or atrial natriuretic peptide (ANP) and brain or B-type natriuretic peptide (BNP), thereby demonstrating an endocrine function for the heart. Studies on the gene encoding ANP (NPPA) initiated the field of modern research into gene regulation in the cardiovascular system. Additionally, ANP and BNP were found to be the natural ligands for cell membrane-bound guanylyl cyclase receptors that mediate the effects of natriuretic peptides through the generation of intracellular cGMP, which interacts with specific enzymes and ion channels. Natriuretic peptides have many physiological actions and participate in numerous pathophysiological processes. Important clinical entities associated with natriuretic peptide research include heart failure, obesity and systemic hypertension. Plasma levels of natriuretic peptides have proven to be powerful diagnostic and prognostic biomarkers of heart disease. Development of pharmacological agents that are based on natriuretic peptides is an area of active research, with vast potential benefits for the treatment of cardiovascular disease.

Functional Role of Natriuretic Peptides in Risk Assessment and Prognosis of Patients with Mitral Regurgitation

The management of mitral valve regurgitation (MR), a common valve disease, represents a challenge in clinical practice, since the indication for either surgical or percutaneous valve replacement or repair are guided by symptoms and by echocardiographic parameters which are not always feasible. In this complex scenario, the use of natriuretic peptide (NP) levels would serve as an additive diagnostic and prognostic tool. These biomarkers contribute to monitoring the progression of the valve disease, even before the development of hemodynamic consequences in a preclinical stage of myocardial damage. They may contribute to more accurate risk stratification by identifying patients who are more likely to experience death from cardiovascular causes, heart failure, and cardiac hospitalizations, thus requiring surgical management rather than a conservative approach. This article provides a comprehensive overview of the available evidence on the role of NPs in the management, risk evaluation, and prognostic assessment of patients with MR both before and after surgical or percutaneous valve repair. Despite largely positive evidence, a series of controversial findings exist on this relevant topic. Recent clinical trials failed to assess the role of NPs following the interventional procedure. Future larger studies are required to enable the introduction of NP levels into the guidelines for the management of MR.