A Test in Context: Neprilysin

68Ga-NOTA-m-SNA006: A Next-Generation CD8-Targeting Nanobody Probe to Enhance Renal and Hepatic Clearance in Noninvasive ImmunoPET Imaging

The 68Ga-labeled nanobody SNA006 marks a significant advancement in noninvasive immunoPET imaging of CD8+ T cells, facilitating real-time tracking of cellular immune responses in cancer, yet its pharmacokinetic properties remain suboptimal. This study aimed to develop a next-generation CD8-targeting immunoPET nanobody probe by incorporating a PEGylated brush border membrane enzyme-cleavable linker to improve pharmacokinetics and to evaluate its characterization in CD8-positive intrapulmonary tumors. A precursor based on SNA006, containing a PEGylated brush border membrane enzyme-cleavable linker, was designed, synthesized, and radiolabeled with gallium-68 to yield 68Ga-NOTA-m-SNA006. The probe was subsequently assessed both in vitro and in vivo. The probe exhibited high radiochemical yield, purity, and favorable stability, and demonstrated binding to the CD8 protein with high affinity. PET/CT imaging and biodistribution studies revealed that 68Ga-NOTA-m-SNA006 exhibited favorable pharmacokinetic properties, including rapid clearance from the kidneys, reduced liver uptake, and sustained retention in the tumor, compared with 68Ga-NODAGA-SNA006. 68Ga-NOTA-m-SNA006 exhibited high uptake in lung lesions during in vivo PET imaging, reflecting CD8 expression in an intrapulmonary tumor model. In summary, we present a novel 68Ga-labeled SNA006 radiotracer with an optimized linker moiety, 68Ga-NOTA-m-SNA006, which effectively decreases renal and hepatic uptake while maintaining tumor uptake, thereby enhancing the tumor-to-background ratio. This approach represents a critical advancement in addressing the persistent challenge of radioactivity in the kidneys and liver associated with nanobody-based radiopharmaceuticals.

Overload of Neprilysin in Placental Extracellular Vesicles Disrupts CNP-NPRB-Mediated Communication Between Vascular Endothelial and Smooth Muscle Cells: A Trigger for Symptoms of Preeclampsia

BACKGROUND

Preeclampsia is a placenta-origin pregnancy complication. Although its development has long been divided into 2 stages: abnormal placentation (stage I) and the release of factors from the hypoperfused placenta into circulation, triggering preeclampsia due to endothelial dysfunction (stage II), the placenta-derived substances coupling the 2 stages remain unclear.

METHODS

Extracellular vesicles (EVs) from normal and preeclampsia-complicated placentas were intravenously administered to pregnant mice, and blood pressure was recorded throughout pregnancy. The differential cargo, including NEP (neprilysin), of placental EVs in normal and preeclamptic placentas was identified by LC-MS, and the cell types involved in NEP expression in the placenta were determined by single-cell RNA sequencing. The effects of placental EVs and recombinant mouse NEP on the uterine arteries were assessed by myography. Placenta-specific NEP overexpression mice were established by in situ injection of adenovirus. The binding affinity between NEP and the vasodilative peptides was determined using an Octet instrument. NEP-overexpressing HUVECs were established to measure CNP (C-type natriuretic peptide) release and cocultured with NPRB (natriuretic peptide receptor-B) knockdown vascular smooth muscle cells (VSMCs) to measure cGMP production in VSMCs.

RESULTS

Placental EVs from preeclamptic pregnancies impaired vascular endothelium-dependent vasodilation and induced preeclampsia in mice. NEP was expressed predominantly by syncytiotrophoblasts and upregulated in placental EVs from preeclamptic pregnancies. Recombinant mouse NEP administration resulted in outcomes like those of administration of placental EVs from preeclamptic pregnancies. Placenta-specific NEP overexpression disturbed maternal hemodynamics, resulting in hypertension and proteinuria of the mice. CNP exhibited high binding affinity for NEP, and NEP upregulation in HUVECs inhibited CNP release, which further influenced the production of cGMP in VSMCs; however, this effect was largely blunted in NPRB-deficient VSMCs.

CONCLUSIONS

Excessive NEP in placental EVs from preeclamptic pregnancies is transported into the endothelial cells of uterine and placental arteries to cleave and degrade CNP, resulting in compromised CNP paracrine activity and NPRB-mediated cGMP production in adjacent VSMCs and triggering the hypertensive manifestation of preeclampsia.

Third-Trimester NT-proBNP for Pre-eclampsia Risk Prediction: A Comparison With sFlt-1/PlGF in a Population-Based Cohort

BACKGROUND

The association between lower first-trimester N-terminal pro B-type natriuretic peptide (NT-proBNP) levels and increased pre-eclampsia risk remains poorly understood, contrasting with the elevated NT-proBNP levels observed at the time of pre-eclampsia diagnosis.

OBJECTIVES

The aim of this study was to assess the utility of third-trimester NT-proBNP for assessing pre-eclampsia risk before onset.

METHODS

NT-proBNP and the soluble Fms-like tyrosine kinase 1 to placental growth factor ratio (sFlt-1/PlGF) were measured in 1,476 pregnant individuals from the Odense Child Cohort at a median gestational age of 29 weeks (Q1-Q3: 28.4-29.4). Pre-eclampsia cases were categorized by timing: 11 individuals (0.7%) developed pre-eclampsia within 4 weeks, while 110 (7.5%) developed pre-eclampsia more than 4 weeks after sampling.

RESULTS

Higher NT-proBNP levels were significantly associated with increased risk of pre-eclampsia within 4 weeks but reduced risk beyond 4 weeks. After adjusting for age, body mass index, nulliparity, systolic blood pressure, and the sFlt-1/PlGF ratio, the adjusted OR was 2.18 (95% CI: 0.88-5.42, P = 0.09) for onset within 4 weeks and 0.72 (95% CI: 0.55-0.93, P = 0.012) for onset beyond 4 weeks. However, combining NT-proBNP with the sFlt-1/PlGF ratio did not improve the predictive accuracy for short- or long-term pre-eclampsia risk compared to the sFlt-1/PlGF ratio alone.

CONCLUSIONS

Unselected NT-proBNP screening in the early third trimester has limited clinical value for predicting short- or long-term pre-eclampsia risk when compared to angiogenic biomarkers.

Selenium Treatment Alleviates the Inhibition Caused by Nep-L Gene Knockdown in Silkworm (Bombyx mori)

Recent studies have emphasized the beneficial effects of 50 μM selenium (Se) on the growth and development of the silkworm, Bombyx mori; however, less is known about its underlying mechanism. To unravel the effect of 50 μM Se on the silkworms with neutral endopeptidase 24.11-like gene (NEP-L) knockdown, we injected small interfering RNA (siRNA) into the body cavity of silkworms. Phenotypic characteristics, mRNA expression of the Nep-L gene, and enriched Se content were evaluated in silkworms from each treatment group. After injecting Nep-L siRNA, the body weight, cocoon quality (cocoon weight, cocoon shell weight, and cocoon shell ratio), and egg production of silkworms were significantly reduced, without any significant effect on egg laying number. However, Se treatment could significantly alleviate the inhibition of body weight, and cocoon quality, without significant effects on egg laying number and production. In addition, the gene knockdown increased Se content in the B. mori. On the molecular level, the targeted Nep-L gene was inhibited significantly by siRNA interference, essentially with the strongest effect at 24 h after RNAi, followed by steady recovery. Among the three fragments, the siRNA of Nep-L-3 was the most effective in interfering with target gene expression. Nep-L gene showed the highest expression in Malpighian tubules (MTs). Both at the phenotypic and genotypic levels, our results show that Nep-L knockdown can exert a significant inhibitory effect on silkworms, and 50 μM Se can reverse the negative effect, which provides a practical prospect for strengthening the silkworm food industry.

Synthesis and biological evaluation of new dual APN/NEP inhibitors as potent analgesics

An alternative approach for the management of acute and chronic pains involves prolonging the half-life of endogenous opiates, such as enkephalins that are released in response to nociceptive stimuli. This can be achieved through the inhibition of enzymatic pathways responsible for the hydrolysis of these peptides, particularly targeting Aminopeptidase N (APN) and Neutral Endopeptidase (NEP). In this study, we designed and synthesized a series of dual enkephalinase inhibitors (DENKIs) targeting both APN and NEP as novel analgesic treatments. Notably, SDUY812, SDUY816 and SDUY817 exhibited potent inhibition of APN activity with IC50 values of 0.38 µM, 0.68 µM and 0.29 µM, respectively, whereas their IC50 values against NEP were 6.9 µM, 6.9 µM and 7.4 µM, separately. In in-vivo antinociceptive assays, SDUY816 and SDUY817 demonstrated superior analgesic efficacy compared to Thiorphan and Bestatin in mice models of acute, inflammatory and neuropathic pains with jumping latencies exceeding 100 s and withdrawal thresholds more than 0.13 g. Moreover, the analgesic activity of these inhibitors was significantly diminished by a potent opioid antagonist, naloxone, indicating the contribution of opioid receptors to the robust analgesic properties of these newly developed DENKIs. In addition, SDUY816 and SDUY817 exerted the analgesic activity in a concentration- and time-dependent manner with SDUY816 possessing acceptable pharmacokinetic properties (t1/2 = 4.02 h and F = 27 %) and low toxicity. These findings provide alternative analgesic therapeutics that are potentially devoid of opioid-associated side effects.

Serum proteomic correlates of mental health symptoms in a representative UK population sample

Poor mental health constitutes a public health crisis due to its high prevalence, unmet need and its mechanistic heterogeneity. A comprehensive understanding of the biological correlates of poor mental health in the population could enhance epidemiological research and eventually help guide treatment strategies. The human bloodstream contains many proteins, several of which have been linked to diagnosed mental health conditions but not to population mental health symptoms, however recent technological advances have made this possible. Here we perform exploratory factor analyses of 184 proteins from two panels (cardiometabolic and neurology-related) measured using proximity extension assays from Understanding Society (the UK Household Longitudinal Study; UKHLS). Data reduction results in 28 factors that explain 55-59% of the variance per panel. We perform multiple linear regressions in up to 5304 participants using two mental health symptom-based outcomes: psychological distress assessed with the general health questionnaire (GHQ-12) and mental health functioning assessed with the 12-Item Short Form Survey, Mental Component Summary (SF12-MCS) using the proteomic factors as explanatory variables and adjusting for demographic covariates. We use backward selection to discard non-significant proteomic factors from the models. Ten factors are independently associated with population mental health symptoms, three of which are immune-related (immunometabolism, immune cell-mediated processes, acute phase processes), three brain-related (neurodevelopment, synaptic processes, neuroprotective processes), two proteolysis-related (proteolysis & the kynurenine pathway, haemostasis & proteolysis), growth factors & muscle, and oxidative stress & the cytoskeleton. Associations partially overlap across the two outcomes, and a sensitivity analysis excluding people taking antidepressants or other central nervous system medications suggestively implicates some of the factors in treatment-resistant poor mental health. Our findings replicate those of case-control studies and expand these to underlie mental health symptomatology in the adult population. More work is needed to understand the direction of causality in these associations.

Rab3gap1 palmitoylation cycling modulates cardiomyocyte exocytosis and atrial natriuretic peptide release

Rab3 GTPase-activating protein 1 (Rab3gap1) hydrolyzes GTP on Rab3 to inactivate it and reinitiate the Rab3 cycle, which regulates exocytic release of neuropeptides and hormones from neuroendocrine cells and atrial natriuretic peptide (ANP) secretion by cardiomyocytes. Cysteine palmitoylation of Rab3gap1 by the Golgi-localized S-acyltransferase zDHHC9 was recently shown to hinder ANP release by impairing Rab3gap1-mediated nucleotide cycling on Rab3a. Here, we interrogate the cysteine residues of Rab3gap1 modified by palmitoylation and impacts on ANP secretion in cardiomyocytes. Although mutation of the previously identified cysteine (Cys)-678 site of Rab3gap1 alone was insufficient to elicit complete loss of Rab3gap1 palmitoylation in cardiomyocytes, combinatorial mutation of Cys-509, 510, 521, 522, and 678 (Rab3gap15CS) dramatically reduced Rab3gap1 palmitoylation. Notably, total cellular GTPase-activating protein (GAP) activity in cardiomyocytes was maintained with mutation of the Rab3gap1 palmitoylation sites as the Rab3gap15CS mutant substantially reduced steady-state Rab3a-GTP levels in cardiomyocytes similar to wild-type Rab3gap1. However, although expression of wild-type Rab3gap1 induced robust secretion of ANP and greatly enhanced phenylephrine-stimulated ANP release, the Rab3gap15CS palmitoylation-deficient mutant was incapable of promoting exocytosis and ANP release by cardiomyocytes. These data suggest Rab3gap1 cysteine palmitoylation may target Rab3gap1 to Rab3a for regulated GAP-mediated inactivation at specific intracellular membrane domains to modulate the Rab3 cycle and exocytosis. Collectively, these data support a role for Rab3gap1 palmitoylation cycling in spatiotemporal control of the Rab3 cycle to regulate exocytosis and ANP secretion by cardiomyocytes.

Evaluation of the Gly-Phe-Lys Linker to Reduce the Renal Radioactivity of a [64Cu]Cu-Labeled Multimeric cRGD Peptide

Radiometal-labeled peptide-based radiopharmaceuticals (RLPB-radiopharmaceuticals) are promising for cancer imaging and targeted radiotherapy; however, their effectiveness is often compromised by the high retention of nonspecific radioactivity in the kidneys due to renal excretion pathways. Current strategies to address this issue have limitations, highlighting the need for innovative approaches to improve targeting specificity and therapeutic efficacy. We aimed to evaluate the applicability of the Gly-Phe-Lys (GFK) tripeptide, a renal brush border (RBB) enzyme-cleavable linkage, to reduce renal radioactivity in RLPB-radiopharmaceuticals using the integrin-targeting radiopeptide [64Cu]Cu-cyclam-RAFT-c(-RGDfK-)4 ([64Cu]Cu-cyclam-RaftRGD). We designed and synthesized the model compound [64Cu]Cu-cyclam-GFK(benzoyl [Bz]), its predictive metabolites, and GFK-incorporated [64Cu]Cu-cyclam-RaftRGD derivatives [64Cu]Cu-cyclam-GFK-RaftRGD and [64Cu]Cu-cyclam-GFK(beta-alanine [βA])3-RaftRGD. In vitro studies showed that dual radiometabolites, namely, [64Cu]Cu-cyclam-G and [64Cu]Cu-cyclam-GF, were simultaneously released from [64Cu]Cu-cyclam-GFK(Bz) by different RBB enzymes, whereas both RaftRGD derivatives released only [64Cu]Cu-cyclam-GF. When injected into mice, [64Cu]Cu-cyclam-GFK(Bz) and the two RaftRGD derivatives led to the urinary excretion of [64Cu]Cu-cyclam-G and [64Cu]Cu-cyclam-GF, respectively. PET imaging and biodistribution studies showed the increased rates of reduction in renal radioactivity levels for the two RaftRGD derivatives compared to the parental [64Cu]Cu-cyclam-RaftRGD (e.g., PET: 1 to 24 h postinjection, 73.0 ± 2.3 and 75.6 ± 1.8 vs 43.0 ± 4.5%, p < 0.0001; biodistribution: 3 to 24 h, 61.1 and 74.4 vs 22.8%). Taken together, these results indicate that the designed renal cleavage occurred in vivo. We also noted the steric interference of the RaftRGD moiety on enzyme access, the spacer effect of the trimeric βA sequence (reduced steric hindrance), and the altered radiopharmacokinetics (e.g., initially increased renal accumulation) of the RaftRGD compounds upon linker incorporation. These findings provide important insights into the chemical design of RLPB-radiopharmaceuticals with reduced renal retention based on the RBB strategy.

Sacubitril/Valsartan in Dialysis Patients: Update on Current Perspectives

Sacubitril/Valsartan is a combination of neprilysin inhibitor and angiotensin II receptor blocker that proved its own efficacy and safety in heart failure patients to ameliorate cardiovascular morbidity and mortality compared to angiotensin II-converting enzyme inhibitors alone. However, end-stage renal disease patients have not been included in the randomized controlled trials, so the beneficial effects as well as the risk profile of this association remain still undefined in these patients. Only observational studies on this drug association have been carried out in end-stage renal disease patients investigating mostly biohumoral or echocardiographic markers. Therefore, its application is still controversial and not free of complications due to the potential risk of hypotension and hyperkaliemia. The efficacy to improve biohumoral markers and cardiac function in dialysis patients and the potential application especially in those patients with severe and resistant hypertension and/or left ventricular dysfunction could be crucial in end-stage renal disease patients. Ongoing long-term randomized controlled trials should thoroughly define the effective benefits and/or adverse effects in patients on substitutive treatment.

Cross talk on therapeutic strategies: natriuretic peptides and inhibiting neprilysin in hypertension management

Hypertension, a prevalent cardiovascular condition globally, remains a significant public health concern due to its association with increased cardiovascular morbidity and mortality. Despite the availability of various antihypertensive therapies, achieving optimal blood pressure control in patients remains a challenge. Valsartan/sacubitril (ARNi), marketed as Entresto by Novartis, combines valsartan, an angiotensin receptor blocker, with sacubitril, an inhibitor of neprilysin. Neprilysin is responsible for breaking down natriuretic peptides and other vasoactive substances. Inhibiting neprilysin prevents the degradation of natriuretic peptides, enhancing their beneficial effects on blood pressure regulation. Natriuretic Peptides, including atrial natriuretic peptide (ANP) and brain natriuretic peptides (BNP), play pivotal roles in regulating blood pressure and cardiovascular homeostasis by promoting vasodilation, natriuresis, and antagonizing the renin-angiotensin-aldosterone system. Therefore, this combo drug lessens sensitivity to natriuretic peptides and tackles the processes in hypertension that activate the renin-angiotensin-aldosterone system. This review provides an overview of how natriuretic peptides (NPs) contribute to blood pressure regulation for the treatment of hypertension through inhibiting neprilysin. It highlights the ARNi's dual action that works synergistically by blocking the harmful effects of angiotensin II on blood vessels while simultaneously increasing the levels of beneficial natriuretic peptides. Schematic representation of the mechanism of action of ARNi. Abbreviation: -Renin angiotensin aldosterone system (RAAS), Natriuretic peptides (NP), Atrial Natriuretic peptide (ANP), Brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), Angiotensin II (Ang II), Angiotensin receptor neprilysin inhibitor (ARNI).

Association of Circulating Neprilysin with BMI, Cardiovascular Health, and Kidney Function in High-Risk Pregnancies: A Pilot Study

BACKGROUND/OBJECTIVES

Inadequate cardiovascular adaptation during pregnancy impairs endothelial function and vascular resistance, contributing to complications such as pre-eclampsia (PE) and gestational hypertension (GH). Neprilysin (NEP), a protease involved in vascular regulation, has been linked to PE, but its role in endothelial function and vascular adaptation remains unclear. This pilot study investigates the associations between soluble neprilysin (sNEP) and markers of vascular and renal function in high-risk pregnancies without PE.

METHODS

Observed parameters were analyzed in 29 high-risk pregnant women across early, mid-, and late pregnancy. sNEP levels were analyzed alongside body mass index (BMI), endothelial dysfunction (ADMA), arterial stiffness (pulse wave velocity, PWV), retinal microvasculature (central retinal arteriolar and venular equivalents, CRAE and CRVE), and kidney function markers. The impact of gestational hypertension (GH) and prior smoking on sNEP levels was also evaluated.

RESULTS

In early and mid-pregnancy, sNEP was inversely associated with BMI. During mid-pregnancy, sNEP showed a positive correlation with CRAE and an inverse correlation with PWV, suggesting reduced arterial stiffness. By late pregnancy, sNEP was positively associated with glomerular filtration rate and inversely correlated with creatinine and protein levels, reflecting improved kidney function. Women with GH exhibited elevated sNEP, while former smokers had lower sNEP levels in early pregnancy.

CONCLUSIONS

These findings suggest that sNEP plays a role in vascular and renal adaption during pregnancy, offering new perspectives on vascular tone regulation in high-risk pregnancies. Further research is needed to clarify these mechanisms and their clinical relevance.

Elevated serum neprilysin levels in patients with chronic hepatitis C and metabolic dysfunction-associated steatotic liver disease: hepatic oxidative stress as an underlying mechanism

BACKGROUND

Neprilysin (NEP) is a metalloprotease that has become a therapeutic target for the treatment of heart failure and hypertension. However, the significance of NEP in chronic liver diseases has rarely been investigated. In this study, we investigated the serum NEP levels in patients with chronic liver disease and their relationship with clinical parameters.

METHODS AND RESULTS

Thirty-seven patients with chronic hepatitis C (CHC) who achieved sustained virologic response (SVR) after antiviral treatment and 73 patients with metabolic dysfunction-associated steatotic liver disease (MASLD) were enrolled. Serum neprilysin levels were measured using an enzyme-linked immunosorbent assay. The median NEP levels were 2.2 ng/mL in CHC and 4.1 ng/mL in MASLD, with the latter being significantly higher. Notably, in patients with MASLD, a significant correlation was observed between NEP and gamma-glutamyltransferase (GGT) levels at baseline. In contrast, there was no significant correlation between NEP levels and progression of liver fibrosis in either group. In the MASLD group, obesity and lifestyle diseases were significantly more prevalent, and the patients exhibited significantly higher NEP levels. In patients with CHC, NEP levels significantly decreased after SVR. NEP mRNA expression in liver tissues was significantly downregulated following SVR. Furthermore, a significant correlation was observed between the degree of NEP and GGT improvement.

CONCLUSIONS

Elevated NEP levels were observed in both CHC and MASLD groups. Considering the association between NEP levels and obesity, lifestyle diseases, and GGT levels, this suggests that oxidative stress may be involved in the elevation of NEP levels in patients with CHC and MASLD.

Association of mid-regional pro-adrenomedullin with office and 24-h ambulatory blood pressure in a Swiss general population sample

OBJECTIVE

Adrenomedullin (ADM) is a potent vasodilator. The association between plasma ADM levels and blood pressure (BP) remains unclear. We assessed the association between mid-regional-pro-ADM (MR-proADM) and BP in a multicenter population- and family-based cohort.

METHODS

We used data from the Swiss Kidney Project on Genes in Hypertension (SKIPOGH). We included participants present at both baseline and 3-year follow-up (N = 843). We examined the association of baseline MR-proADM with baseline office and 24 h ambulatory BP as well as the 3-year change in office BP. In secondary analyses, we studied the association between baseline MR-proADM and 3-year changes in pulse wave velocity (PWV), renal resistive index (RRI) and augmentation index (AI). Mixed-effects linear regression models were used.

RESULTS

In cross-sectional analyses, MR-proADM was negatively associated with office, 24-h and daytime diastolic BP (DBP). MR-proADM was positively associated with nighttime systolic BP (SBP). In longitudinal analyses, baseline MR-proADM was associated with an increase in office SBP and pulse pressure (PP) over 3 years [β (95% CI): 8.2 (0.4, 15.9) and β (95% CI): 6.4 (0.3, 12.4), respectively] but not with changes in PWV, RRI and AI.

CONCLUSIONS

The cross-sectional negative association of MR-proADM with DBP is in line with known vasodilatory properties of ADM. The positive association between MR-proADM and nighttime SBP at baseline may reflect endothelial dysfunction believed to be part of the pathogenesis of nocturnal hypertension. The association of higher baseline MR-proADM levels with increased SBP and PP at 3-year follow-up suggests that ADM levels could be a marker of cardiovascular risk.

Metabolic and Immunological Implications of MME+CAF-Mediated Hypoxia Signaling in Pancreatic Cancer Progression: Therapeutic Insights and Translational Opportunities

Pancreatic cancer is a devastating malignancy with a high mortality rate, poor prognosis, and limited treatment options. The tumor microenvironment (TME) plays a crucial role in tumor progression and therapy resistance. Multiple subpopulations of cancer-associated fibroblasts (CAFs) within the TME can switch between different states, exhibiting both antitumorigenic and protumorigenic functions in pancreatic cancer. It seems that targeting fibroblast-related proteins and other stromal components is an appealing approach to combat pancreatic cancer. This study employed single-cell transcriptome sequencing to identify MME (Membrane Metalloendopeptidase)-expressing CAFs in pancreatic cancer. Systematic screening was conducted based on tumor differentiation, lymph node metastasis, and T-stage parameters to identify and confirm the existence of a subpopulation of fibroblasts termed MME+CAFs. Subsequent analyses included temporal studies, exploration of intercellular communication patterns focusing on the hypoxia signaling pathway, and investigation of MME+CAF functions in the pancreatic cancer microenvironment. The pathway enrichment analysis and clinical relevance revealed a strong association between high MME expression and glycolysis, hypoxia markers, and pro-cancer inflammatory pathways. The role of MME+CAFs was validated through in vivo and in vitro experiments, including high-throughput drug screening to evaluate potential targeted therapeutic strategies. Single-cell transcriptome sequencing revealed tumor-associated fibroblasts with high MME expression, termed MME+CAF, exhibiting a unique end-stage differentiation function in the TME. MME+CAF involvement in the hypoxia signaling pathway suggested the potential effects on pancreatic cancer progression through intercellular communication. High MME expression was associated with increased glycolysis, hypoxia markers (VEGF), and pro-cancer inflammatory pathways in pancreatic cancer patients, correlating with lower survival rates, advanced disease stage, and higher oncogene mutation rates. Animal experiments confirmed that elevated MME expression in CAFs increases tumor burden, promotes an immunosuppressive microenvironment, and enhances resistance to chemotherapy and immunotherapy. The developed MME+CAF inhibitor IOX2 (a specific prolyl hydroxylase-2 (PHD2) inhibitor), combined with AG (Paclitaxel + Gemcitabine) and anti-PD1 therapy, demonstrated promising antitumor effects, offering a translational strategy for targeting MME in CAFs of pancreatic cancer. The study findings highlighted the significant role of MME+CAF in pancreatic cancer progression by shaping the TME and influencing key pathways. Targeting MME presented a promising strategy to combat the disease, with potential implications for therapeutic interventions aimed at disrupting MME+CAF functions and enhancing the efficacy of pancreatic cancer treatments.

Study on the Effects of Angiotensin Receptor/Neprilysin Inhibitors on Renal Haemodynamics in Healthy Dogs

An angiotensin receptor/neprilysin inhibitor (ARNI), a heart failure treatment, is a combination drug made up of sacubitril, a neprilysin inhibitor, and valsartan, a vascular receptor blocker. No human or veterinary studies regarding the effect of ARNI on renal haemodynamics in the absence of cardiac or renal issues exist. Therefore, we investigated the effect of ARNI on renal haemodynamics in five healthy dogs. ARNI was administered to all five dogs at an oral dose of 20 mg/kg twice daily for 4 weeks. Renal haemodynamics were assessed on the day before ARNI administration (BL), on Day 7, and on Day 28. The glomerular filtration rate (GFR) significantly increased on Day 28 compared to BL and Day 7, whereas renal plasma flow increased on Day 7 and Day 28 compared to BL. Systolic blood pressure significantly decreased between BL and Day 28. Plasma atrial natriuretic peptide (ANP) concentrations increased on Day 7 compared to BL. Additionally, ANP concentrations increased on Day 28 in three of the five dogs. Different ANP concentrations were observed in the remaining two dogs. Both urine output volume and heart rate remained relatively stable and did not exhibit significant change. In conclusion, ARNI may enhance renal haemodynamics in healthy dogs. ARNI could be a valuable drug for treating both heart and kidney disease in dogs.

Challenging and target-based shifting strategies for heart failure treatment: An update from the last decades

Heart failure (HF) is a major global health problem afflicting millions worldwide. Despite the significant advances in therapies and prevention, HF still carries very high morbidity and mortality, requiring enormous healthcare-related expenditure, and the search for new weapons goes on. Following initial treatment strategies targeting inotropism and congestion, attention has focused on offsetting the neurohormonal overactivation and three main therapies, including angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor antagonists, β-adrenoceptor antagonists, and mineralocorticoid receptor antagonists, have been the foundation of standard treatment for patients with HF. Recently, a paradigm shift, including angiotensin receptor-neprilysin inhibitor, sodium glucose co-transporter 2 inhibitor, and ivabradine, has been added. Moreover, soluble guanylate cyclase stimulator, elamipretide, and omecamtiv mecarbil have come out as a next-generation therapeutic agent for patients with HF. Although these pharmacologic therapies have been significantly successful in relieving symptoms, there is still no complete cure for HF. We may be currently entering a new era of treatment for HF with animal experiments and human clinical trials assessing the value of antibody-based immunotherapy and gene therapy as a novel therapeutic strategy. Such tempting therapies still have some challenges to be addressed but may become a weighty option for treatment of HF. This review article will compile the paradigm shifts in HF treatment over the past dozen years or so and illustrate current landscape of antibody-based immunotherapy and gene therapy as a new therapeutic algorithm for patients with HF.

A structure-based pharmacophore modelling approach to identify and design new neprilysin (NEP) inhibitors: An in silico-based investigation

Neutral endopeptidase or neprilysin (NEP) cleaves the natriuretic peptides, bradykinin, endothelin, angiotensin II, amyloid β protein, substance P, etc., thus modulating their effects on heart, kidney, and other organs. NEP has a proven role in hypertension, heart disease, renal disease, Alzheimer's, diabetes, and some cancers. NEP inhibitor development has been in focus since the US FDA approved a combination therapy of angiotensin II type 1 receptor inhibitor (valsartan) and NEP inhibitor (sacubitril) for use in heart failure. Considering the importance of NEP inhibitors the present work focuses on the designing of a potential lead for NEP inhibition. A structure-based pharmacophore modelling approach was employed to identify NEP inhibitors from the pool of 1140 chemical entities obtained from the ZINC database. Based on the docking score and pivotal interactions, ten molecules were selected and subjected to binding free energy calculations and ADMET predictions. The top two compounds were studied further by molecular dynamics simulations to determine the stability of the ligand-receptor complex. ZINC0000004684268, a phenylalanine derivative, showed affinity and complex stability comparable to sacubitril. However, in silico studies indicated that it may have poor pharmacokinetic parameters. Therefore, the molecule was optimized using bioisosteric replacements, keeping the phenylalanine moiety intact, to obtain five potential lead molecules with an acceptable pharmacokinetic profile. The works thus open up the scope to further corroborate the present in silico findings with the biological analysis.

Protein-to-DNA Converter with High Signal Gain

DNA isothermal amplification techniques have been applied extensively for evaluating nucleic acid inputs but cannot be implemented directly on other types of biomolecules. In this work, we designed a proximity activation mechanism that converts protein input into DNA barcodes for the DNA exponential amplification reaction, which we termed PEAR. Several design parameters were identified and experimentally verified, which included the choice of enzymes, sequences of proximity probes and template strand via the NUPACK design tool, and the implementation of a hairpin lock on the proximity probe structure. Our PEAR system was surprisingly more robust against nonspecific DNA amplification, which is a major challenge faced in existing formats of the DNA-based exponential amplification reaction. The as-designed PEAR exhibited good target responsiveness for three protein models with a dynamic range of 4-5 orders of magnitude down to femtomolar input concentration. Overall, our proposed protein-to-DNA converter module led to the development of a stable and robust configuration of the DNA exponential amplification reaction to achieve high signal gain. We foresee this enabling the use of protein inputs for more complex molecular evaluation as well as ultrasensitive protein detection.

A comprehensive review of the literature on CD10: its function, clinical application, and prospects

CD10, a zinc-dependent metalloprotease found on the cell surface, plays a pivotal role in an array of physiological and pathological processes including cardiovascular regulation, immune function, fetal development, pain response, oncogenesis, and aging. Recognized as a biomarker for hematopoietic and tissue stem cells, CD10 has garnered attention for its prognostic potential in the progression of leukemia and various solid tumors. Recent studies underscore its regulatory significance and therapeutic promise in combating Alzheimer's disease (AD), and it is noted for its protective role in preventing heart failure (HF), obesity, and type-2 diabetes. Furthermore, CD10/substance P interaction has also been shown to contribute to the pain signaling regulation and immunomodulation in diseases such as complex regional pain syndrome (CRPS) and osteoarthritis (OA). The emergence of COVID-19 has sparked interest in CD10's involvement in the disease's pathogenesis. Given its association with multiple disease states, CD10 is a prime therapeutic target; inhibitors targeting CD10 are now being advanced as therapeutic agents. This review compiles recent and earlier literature on CD10, elucidating its physicochemical attributes, tissue-specific expression, and molecular functions. Furthermore, it details the association of CD10 with various diseases and the clinical advancements of its inhibitors, providing a comprehensive overview of its growing significance in medical research.

ADAM10 and Neprilysin level decreases in immune cells of mice bearing metastatic breast carcinoma: Possible role in cancer inflammatory response

OBJECTIVE AND DESIGN

ADAM10 and Neprilysin, proteases, play critical role in inflammatory disease, however their role in cancer immune response is not clear. We here evaluated changes in immune response using an experimental model for breast cancer.

MATERIAL AND METHOD

Highly metastatic breast cancer cells (4T1-derived) were injected orthotopically (mammary-pad of Balb-c mice) to induce tumors. Changes in enzyme level and activity as well as alterations in inflammatory cytokine release in the presence or absence of ADAM10 and NEP activity was determined using specific inhibitors and recombinant proteins. Cytokine response was evaluated using mix leucocyte cultures obtained from control and tumor-bearing mice. ANOVA with Dunnett's posttest was used for statistical analysis.

RESULTS

ADAM10 and NEP expression was decreased markedly in lymph nodes and spleens of tumor-bearing mice. ADAM10 activity was reduced together with apparent alterations of ADAM10 processing. ADAM10 and NEP activity decreased TNF-α, IL-6 and IFN-ɣ secretion. Suppression of these inflammatory cytokines were more prominent in cultures obtained from control mice demonstrating counteracting factors that are exist in tumor-bearing mice.

CONCLUSION

Loss of ADAM10 and NEP activity in immune cells during breast cancer metastasis might be one of the main factors involved in induction of chronic inflammation by tumors.

Multiple circulating forms of neprilysin detected with novel epitope-directed monoclonal antibodies

Neprilysin (NEP) is an emerging biomarker for various diseases including heart failure (HF). However, major inter-assay inconsistency in the reported concentrations of circulating NEP and uncertainty with respect to its correlations with type and severity of disease are in part attributed to poorly characterized antibodies supplied in commercial ELISA kits. Validated antibodies with well-defined binding footprints are critical for understanding the biological and clinical context of NEP immunoassay data. To achieve this, we applied in silico epitope prediction and rational peptide selection to generate monoclonal antibodies (mAbs) against spatially distant sites on NEP. One of the selected epitopes contained published N-linked glycosylation sites at N285 and N294. The best antibody pair, mAb 17E11 and 31E1 (glycosylation-sensitive), were characterized by surface plasmon resonance, isotyping, epitope mapping, and western blotting. A validated two-site sandwich NEP ELISA with a limit of detection of 2.15 pg/ml and working range of 13.1-8000 pg/ml was developed with these mAbs. Western analysis using a validated commercial polyclonal antibody (PE pAb) and our mAbs revealed that non-HF and HF plasma NEP circulates as a heterogenous mix of moieties that possibly reflect proteolytic processing, post-translational modifications and homo-dimerization. Both our mAbs detected a ~ 33 kDa NEP fragment which was not apparent with PE pAb, as well as a common ~ 57-60 kDa moiety. These antibodies exhibit different affinities for the various NEP targets. Immunoassay results are dependent on NEP epitopes variably detected by the antibody pairs used, explaining the current discordant NEP measurements derived from different ELISA kits.

Effects of sacubitril-valsartan in patients undergoing maintenance dialysis

OBJECTIVES

Data on angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril-valsartan (SV) in patients undergoing maintenance dialysis is scarce. Our study aimed to investigate the effect of SV on patients undergoing dialysis.

METHODS

We retrospectively reviewed the data of end-stage kidney disease (ESRD) patients undergoing either peritoneal dialysis (PD) or hemodialysis (HD) in our center. A total of 51 patients receiving SV treatment were enrolled in the SV group. Another 51 age and sex-matched patients on dialysis without SV treatment were selected as the control group. All the patients were regularly followed up in the dialysis clinic. Their clinical, biochemical, and echocardiographic parameters were all recorded at baseline and during follow-up. The effect and safety of SV were further analyzed.

RESULTS

A total of 102 ESRD patients on dialysis (51 patients in the SV group and 51 patients in the control group) were finally enrolled. The median follow-up time was 349 days (interquartile range [IQR]: 217-535 days). The level of B-type natriuretic peptide (BNP) (median [IQR] before and after SV treatment: 596.35 pg/ml [190.6-1714.85] vs. 188.7 pg/ml [83.34-600.35], p < 0.001) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) (median [IQR]: 6316.00 pg/ml [4552.00-28598.00] vs. 5074.00 pg/ml [2229.00-9851.00], p = 0.022) were significantly decreased after treatment with SV. The variant rate of left ventricular ejection fraction (LVEF) was significantly higher in the SV group compared to the control group, especially in the PD subgroup. No significant difference was found in other echocardiographic parameters between SV and control group. Subgroup analysis of the PD group showed an increase in daily PD ultrafiltration (median [IQR]: 400 ml/d [200-500] vs. 500 ml/d [200-850], p = 0.114) after SV treatment. Variant rate of overhydration (OH) measured by the body composition monitor (BCM) of the SV group were significantly different from the control group (median [IQR]: -13.13% [-42.85%-27.84%] vs. 0% [-17.95%-53.85%], p = 0.049). The rate of hyperkalemia was slightly higher but without significant difference before and after the introduction of SV (19.6% vs. 27.5%, p = 0.350). No event of hypotension and angioedema were observed.

CONCLUSIONS

SV might have a cardio-protective role in ESRD patients undergoing dialysis, especially in PD patients. Serum potassium should be monitored during the treatment.

Clinical and Hemodynamic Improvement in Pulmonary Hypertension After Switching to Sacubitril/Valsartan in Patients With Heart Failure With Preserved Ejection Fraction

ABSTRACT

Patients with heart failure with preserved ejection fraction (HFpEF) and pulmonary hypertension have poor survival, and established medical therapies for both conditions are not available. In this retrospective study of 69 patients with HFpEF and either isolated postcapillary pulmonary hypertension (IpcPH, n = 53) or combined postcapillary and precapillary pulmonary hypertension (CpcPH, n = 16), we investigated the effects of sacubitril/valsartan on pulmonary hypertension measured using right heart catheterization at baseline (ie, presacubitril/valsartan) and 99 (94-123) days after switching to sacubitril/valsartan. After switching to sacubitril/valsartan, right heart catheterization showed significantly lower pulmonary artery pressures (systolic/diastolic/mean) in both patient groups compared with presacubitril/valsartan [IpcPH: 44 (38-52)/15 (12-19)/28 (22-33) mm Hg vs. 47 (40-55)/18 (15-23)/31 (26-35) mm Hg, P < 0.01; CpcPH: 54 (43-57)/18 (12-23)/34 (30-36) mm Hg vs. 61 (50-79)/24 (19-30)/40 (31-53) mm Hg, P < 0.05]. The median sacubitril/valsartan dose at follow-up was 24/26 (24/26-49/51) mg twice daily in both patients with IpcPH and CpcPH. Clinically, the New York Heart Association functional class improved by at least 1 class in 32 of 69 patients ( P < 0.01). In conclusion, sacubitril/valsartan therapy improves pulmonary hypertension in patients with HFpEF and either IpcPH or CpcPH. Further prospective randomized trials are needed for confirmation of our results.

Tutorial review for peptide assays: An ounce of pre-analytics is worth a pound of cure

The recent increase in peptidomimetic-based medications and the growing interest in peptide hormones has brought new attention to the quantification of peptides for diagnostic purposes. Indeed, the circulating concentrations of peptide hormones in the blood provide a snapshot of the state of the body and could eventually lead to detecting a particular health condition. Although extremely useful, the quantification of such molecules, preferably by liquid chromatography coupled to mass spectrometry, might be quite tricky. First, peptides are subjected to hydrolysis, oxidation, and other post-translational modifications, and, most importantly, they are substrates of specific and nonspecific proteases in biological matrixes. All these events might continue after sampling, changing the peptide hormone concentrations. Second, because they include positively and negatively charged groups and hydrophilic and hydrophobic residues, they interact with their environment; these interactions might lead to a local change in the measured concentrations. A phenomenon such as nonspecific adsorption to lab glassware or materials has often a tremendous effect on the concentration and needs to be controlled with particular care. Finally, the circulating levels of peptides might be low (pico- or femtomolar range), increasing the impact of the aforementioned effects and inducing the need for highly sensitive instruments and well-optimized methods. Thus, despite the extreme diversity of these peptides and their matrixes, there is a common challenge for all the assays: the need to keep concentrations unchanged from sampling to analysis. While significant efforts are often placed on optimizing the analysis, few studies consider in depth the impact of pre-analytical steps on the results. By working through practical examples, this solution-oriented tutorial review addresses typical pre-analytical challenges encountered during the development of a peptide assay from the standpoint of a clinical laboratory. We provide tips and tricks to avoid pitfalls as well as strategies to guide all new developments. Our ultimate goal is to increase pre-analytical awareness to ensure that newly developed peptide assays produce robust and accurate results.

Novel aspect of neprilysin in kidney fibrosis via ACSL4-mediated ferroptosis of tubular epithelial cells

Although inhibition of neprilysin (NEP) might be a therapeutic strategy with the potential to improve the outcome of chronic kidney disease (CKD), the versatile function of NEP with its mechanism remains obscure in kidney fibrosis. In the study, we found that NEP was abnormally increased in tubular epithelial cells of CKD patients, as well as unilateral ureteral obstruction and adenine diet-induced mice. Treatment with a United States Food and Drug Administration-approved NEP inhibitor Sacubitrilat (LBQ657) could alleviate ferroptosis, tubular injury, and delay the progression of kidney fibrosis in experimental mice. Similarly, genetic knockdown of NEP also inhibited tubular injury and fibrosis in transforming growth factor (TGF)-β1 -induced tubular cells. Mechanically, NEP overexpression aggravated the ferroptotic and fibrotic phenotype, which was restored by acyl-CoA synthetase long-chain family member 4 (ACSL4) knockdown. The NEP silencing attenuated TGF-β1-induced tubular cell ferroptosis and was exacerbated by ACSL4 overexpression. Collectively, for the first time, a novel aspect of NEP was explored in kidney fibrosis through ACSL4-mediated tubular epithelial cell ferroptosis. Our data further confirmed that NEP inhibition exerted a promising therapeutic against fibrotic kidney diseases.

Metabolic Approaches for the Treatment of Dilated Cardiomyopathy

In dilated cardiomyopathy (DCM), where the heart muscle becomes stretched and thin, heart failure (HF) occurs, and the cardiomyocytes suffer from an energetic inefficiency caused by an abnormal cardiac metabolism. Although underappreciated as a potential therapeutic target, the optimal metabolic milieu of a failing heart is still largely unknown and subject to debate. Because glucose naturally has a lower P/O ratio (the ATP yield per oxygen atom), the previous studies using this strategy to increase glucose oxidation have produced some intriguing findings. In reality, the vast majority of small-scale pilot trials using trimetazidine, ranolazine, perhexiline, and etomoxir have demonstrated enhanced left ventricular (LV) function and, in some circumstances, myocardial energetics in chronic ischemic and non-ischemic HF with a reduced ejection fraction (EF). However, for unidentified reasons, none of these drugs has ever been tested in a clinical trial of sufficient size. Other pilot studies came to the conclusion that because the heart in severe dilated cardiomyopathy appears to be metabolically flexible and not limited by oxygen, the current rationale for increasing glucose oxidation as a therapeutic target is contradicted and increasing fatty acid oxidation is supported. As a result, treating metabolic dysfunction in HF may benefit from raising ketone body levels. Interestingly, treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2i) improves cardiac function and outcomes in HF patients with or without type 2 diabetes mellitus (T2DM) through a variety of pleiotropic effects, such as elevated ketone body levels. The improvement in overall cardiac function seen in patients receiving SGLT2i could be explained by this increase, which appears to be a reflection of an adaptive process that optimizes cardiac energy metabolism. This review aims to identify the best metabolic therapeutic approach for DCM patients, to examine the drugs that directly affect cardiac metabolism, and to outline all the potential ancillary metabolic effects of the guideline-directed medical therapy. In addition, a special focus is placed on SGLT2i, which were first studied and prescribed to diabetic patients before being successfully incorporated into the pharmacological arsenal for HF patients.

Effects of Sacubitril/Valsartan on Exercise Capacity in Patients with Heart Failure with Reduced Ejection Fraction and the Role of Percentage of Delayed Enhancement Measured by Cardiac Magnetic Resonance in Predicting Therapeutic Response: A Multicentre Study

Background: This study aims to evaluate the cardiopulmonary effects of sacubitril/valsartan therapy in patients with heart failure with reduced ejection fraction (HFrEF), investigating a possible correlation with the degree of myocardial fibrosis, as assessed by cardiac magnetic resonance. Methods: A total of 134 outpatients with HFrEF were enrolled. Results: After a mean follow-up of 13.3 ± 6.6 months, an improvement in ejection fraction and a reduction in E/A ratio, inferior vena cava size and N-terminal pro-B-type natriuretic peptide levels were observed. At follow-up, we observed an increase in VO₂ peak of 16% (p<0.0001) and in O₂ pulse of 13% (p=0.0002) as well as an improvement in ventilatory response associated with a 7% reduction in the VE/VCO₂ slope (p=0.0001). An 8% increase in the ΔVO₂/Δ work ratio and an 18% increase in exercise tolerance were also observed. Multivariate logistic regression analysis showed that the main predictors of events during follow-up were VE/VCO₂ slope >34 (OR 3.98; 95% CI [1.59-10.54]; p=0.0028); ventilatory oscillatory pattern (OR 4.65; 95% CI [1.55-16.13]; p=0.0052); and haemoglobin level (OR 0.35; 95% CI [0.21-0.55]; p<0.0001). In patients who had cardiac magnetic resonance, when delayed enhancement >4.6% was detected, a lower response after sacubitril/valsartan therapy was observed as expressed by improvement in ΔVO₂ peak, O₂ pulse, LVEF and N-terminal pro-B-type natriuretic peptide. No significant differences were observed in ΔVO₂/Δ work and VE/VCO₂ slope. Conclusion:Sacubitril/valsartan improves cardiopulmonary functional capacity in HFrEF patients. The presence of myocardial fibrosis on cardiac magnetic resonance is a predictor of response to therapy.

Sacubitril/valsartan: research progress of multi-channel therapy for cardiorenal syndrome

Cardiorenal syndrome (CRS) results from complex interaction between heart and kidneys, inducing simultaneous acute or chronic dysfunction of these organs. Although its incidence rate is increasing with higher mortality in patients, effective clinical treatment drugs are currently not available. The literature suggests that renin-angiotensin-aldosterone system (RAAS) and diuretic natriuretic peptide (NP) system run through CRS. Drugs only targeting the RAAS and NPs systems are not effective. Sacubitril/valsartan contains two agents (sacubitril and valsartan) that can regulate RAAS and NPs simultaneously. In the 2017 American College of Cardiology/American Heart Association/American Heart Failure (HF) ssociation (ACC/AHA/HFSA) guideline, sacubitril/valsartan was recommended as standard therapy for HF patients. The latest research shows that Combined levosimendan and Sacubitril/Valsartan markets are protected the heart and kidney against cardiovascular syndrome in rat. However, fewer studies have reported its therapeutic efficacy in CRS treatment, and their results are inconclusive. Therefore, based on RAAS and NPs as CRS biomarkers, this paper summarizes possible pathophysiological mechanisms and preliminary clinical application effects of sacubitril/valsartan in the prevention and treatment of CRS. This will provide a pharmacological justification for expanding sacubitril/valsartan use to the treatment of CRS.

Natriuretic peptides: role in the diagnosis and management of heart failure: a scientific statement from the Heart Failure Association of the European Society of Cardiology, Heart Failure Society of America and Japanese Heart Failure Society

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

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

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

Natriuretic Peptides: It Is Time for Guided Therapeutic Strategies Based on Their Molecular Mechanisms

Natriuretic peptides (NPs) are the principal expression products of the endocrine function of the heart. They exert several beneficial effects, mostly mediated through guanylate cyclase-A coupled receptors, including natriuresis, diuresis, vasorelaxation, blood volume and blood pressure reduction, and regulation of electrolyte homeostasis. As a result of their biological functions, NPs counterbalance neurohormonal dysregulation in heart failure and other cardiovascular diseases. NPs have been also validated as diagnostic and prognostic biomarkers in cardiovascular diseases such as atrial fibrillation, coronary artery disease, and valvular heart disease, as well as in the presence of left ventricular hypertrophy and severe cardiac remodeling. Serial measurements of their levels may be used to contribute to more accurate risk stratification by identifying patients who are more likely to experience death from cardiovascular causes, heart failure, and cardiac hospitalizations and to guide tailored pharmacological and non-pharmacological strategies with the aim to improve clinical outcomes. On these premises, multiple therapeutic strategies based on the biological properties of NPs have been attempted to develop new targeted cardiovascular therapies. Apart from the introduction of the class of angiotensin receptor/neprilysin inhibitors to the current management of heart failure, novel promising molecules including M-atrial natriuretic peptide (a novel atrial NP-based compound) have been tested for the treatment of human hypertension with promising results. Moreover, different therapeutic strategies based on the molecular mechanisms involved in NP regulation and function are under development for the management of heart failure, hypertension, and other cardiovascular conditions.

Endocrine functions of the heart: from bench to bedside

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

Renal Safety of Sacubitril/Valsartan: A Meta-Analysis of Randomized Controlled Trials

ABSTRACT

As a first-line therapy, sacubitril/valsartan (S/V) plays a significant role in the treatment of heart failure. However, its effect on renal function is still uncertain. We searched PubMed, EMBASE, the Cochrane Library, and Clinical Trials for randomized controlled trials to evaluate the effect of S/V on renal function in patients. The results are reported as the mean difference, relative ratio, and 95% confidence intervals. A total of 13 randomized controlled trials were included (19,367 patients). Among them, 11 studies focused on patients with heart failure, 1 on patients with acute myocardial infarction, and 1 on patients with chronic kidney disease. We found that fewer worsening renal function events, elevated creatine level events, and severe hyperkalemia events (blood potassium >6.0 mmol/L) occurred in the S/V group than those in the renin-angiotensin-aldosterone system inhibitor (RASi) group. The estimated glomerular filtration rate decreased in both the S/V group and the RASi group, but the change was more obvious in the RASi group. There was no significant difference in hyperkalemia events (blood potassium >5.5 mmol/L) between the 2 groups. Subgroup analysis showed that with the extension of follow-up time (>6 months), worsening renal function events occurred less frequently in the S/V group than in the RASi group. Existing evidence has shown that S/V is superior to RASi in general renal safety. Perhaps with the prolongation of treatment time, the advantages of S/V are more obvious.

Neprilysin 4: an essential peptidase with multifaceted physiological relevance

Neprilysins are highly conserved ectoenzymes that hydrolyze and thus inactivate signaling peptides in the extracellular space. Herein, we focus on Neprilysin 4 from Drosophila melanogaster and evaluate the existing knowledge on the physiological relevance of the peptidase. Particular attention is paid to the role of the neprilysin in regulating feeding behavior and the expression of insulin-like peptides in the central nervous system. In addition, we assess the function of the peptidase in controlling the activity of the sarcoplasmic and endoplasmic reticulum Ca²⁺ ATPase in myocytes, as well as the underlying molecular mechanism in detail.

Enzymological Characterization of 64Cu-Labeled Neprilysin Substrates and Their Application for Modulating the Renal Clearance of Targeted Radiopharmaceuticals

The applicability of radioligands for targeted endoradionuclide therapy is limited due to radiation-induced toxicity to healthy tissues, in particular to the kidneys as primary organs of elimination. The targeting of enzymes of the renal brush border membrane by cleavable linkers that permit the formation of fast eliminating radionuclide-carrying cleavage fragments gains increasing interest. Herein, we synthesized a small library of ⁶⁴Cu-labeled cleavable linkers and quantified their substrate potentials toward neprilysin (NEP), a highly abundant peptidase at the renal brush border membrane. This allowed for the derivation of structure-activity relationships, and selected cleavable linkers were attached to the somatostatin receptor subtype 2 ligand [Tyr³]octreotate. Radiopharmacological characterization revealed that a substrate-based targeting of NEP in the kidneys with small peptides entails their premature cleavage in the blood circulation by soluble and endothelium-derived NEP. However, for a kidney-specific targeting of NEP, the additional targeting of albumin in the blood is highlighted.

Alpha Ketoglutarate Downregulates the Neutral Endopeptidase and Enhances the Growth Inhibitory Activity of Thiorphan in Highly Aggressive Osteosarcoma Cells

Since natural substances are widely explored as epigenetic modulators of gene expression and epigenetic abnormalities are important causes of cancerogenesis, factors with pro-tumor activities subjected to epigenetic control, e.g., neutral endopeptidase (NEP, neprilysin), are promising anticancer targets for potential therapies acting via epigenetic regulation of gene expression. Alpha-ketoglutarate (AKG) is a naturally occurring co-substrate for enzymes involved in histone and DNA demethylation with suggested anti-cancer activity. Hence, we investigated a potential effect of AKG on the NEP expression in cells derived from various cancers (cervical, colon, osteosarcoma) and normal epithelial cells and osteoblasts. Moreover, the overall methylation status of histone H3 was explored to establish the molecular target of AKG activity. Additionally, it was investigated whether AKG in combination with thiorphan (NEP specific inhibitor) exhibited enhanced anticancer activity. The results revealed that AKG downregulated the expression of NEP at the protein level only in highly aggressive osteosarcoma HOS cells (flow cytometry and fluorometric assays), and this protease was found to be involved in AKG-induced growth inhibition in osteosarcoma cells (siRNA NEP silencing, BrdU assay, flow cytometry). Unexpectedly, AKG-induced hypermethylation of H3K27 in HOS cells, which was partially dependent on EZH2 activity. However, this effect was not implicated in the AKG-induced NEP downregulation (flow cytometry). Finally, the combined treatment with AKG and thiorphan was shown to significantly enhance the growth inhibitory potential of each one towards HOS cells (BrdU assay). These preliminary studies have shown for the first time that the downregulation of NEP expression is a promising target in therapies of NEP-implicating HOS cells. Moreover, this therapeutic goal can be achieved via AKG-induced downregulation of NEP and synergistic activity of AKG with thiorphan, i.e., a NEP specific inhibitor. Furthermore, this study has reported for the first time that exogenous AKG can influence the activity of histone methyltransferase, EZH2. However, this issue needs further investigation to elucidate the mechanisms of this phenomenon.

Augmentation of Natriuretic Peptide Bioactivity via Combined Inhibition of Neprilysin and Phosphodiesterase-9 in Heart Failure

BACKGROUND

The natriuretic peptides (NPs) are potent natriuretic/diuretic and vasodilatory factors, and augmentation of their levels or signaling via inhibition of the enzymes neprilysin (NEP) and phosphodiesterase 9 (PDE9), respectively, has beneficial actions in heart failure (HF).

OBJECTIVES

The authors investigated dual enhancement of NP bioactivity by combining PDE9 inhibition and NEP inhibition in HF using an ovine model.

METHODS

Eight sheep with pacing-induced HF received on 4 separate days intravenous PDE9 inhibition (PF-04749982), NEP inhibition (SCH-32615), PDE9 inhibition + NEP inhibition (PI+NI), and vehicle control treatment.

RESULTS

Compared with the control treatment, NEP inhibition significantly increased plasma NP concentrations with a corresponding rise in second messenger cyclic guanosine monophosphate (cGMP), whereas PDE9 inhibition increased circulating cGMP with a negligible effect on NP levels. Combined PI+NI elevated plasma NPs to an extent comparable to that seen with NEP inhibition alone but further increased cGMP, resulting in a rise in the cGMP-to-NP ratio. All active treatments reduced mean arterial pressure, left atrial pressure, pulmonary arterial pressure, and peripheral resistance, with combined PI+NI further reducing mean arterial pressure and left atrial pressure relative to either inhibitor separately. Active treatments increased urine volume and sodium, potassium and creatinine excretion, and creatinine clearance, in association with rises in urine cGMP levels. PI+NI induced a significantly greater natriuresis and increase in urinary cGMP relative to either inhibitor singly.

CONCLUSIONS

The present study demonstrates for the first time that combined PI+NI has additional beneficial hemodynamic and renal effects when compared with either PDE9 inhibition or NEP inhibition alone. The superior efficacy of this 2-pronged augmentation of NP bioactivity supports PI+NI as a potential therapeutic strategy for HF.

What do we know about the renin angiotensin system and inflammatory bowel disease?

INTRODUCTION

The renin-angiotensin system (RAS) is an important homeostatic pathway, with emerging evidence for the impact of its components on inflammation and fibrosis in gastrointestinal tissues. This review aims to review current knowledge of the physiological mechanism of RAS in inflammatory bowel disease (IBD), and potential therapeutic implications.

AREAS COVERED

An extensive online literature review including Pubmed, Medline, and Google Scholar was undertaken. Discussion on the components of the RAS, localization, and physiological functions in the gastrointestinal tract, preclinical, and clinical data in IBD, and the relation with SARS-Cov-2 are covered in this review.

EXPERT OPINION

RAS inhibition may have a role as anti-fibrotic adjunct therapy. Targeting the local gastrointestinal RAS with novel modes of delivery may be a target for future therapeutics for IBD, given the widespread availability and safety of current options as utilized in other diseases. Further insight into the mechanism and downstream effects of gastrointestinal ACE2 may lead to a better understanding of the pathogenesis of IBD.

Endothelial and Vascular Smooth Muscle Dysfunction in Hypertension

The development of essential hypertension involves several factors. Vascular dysfunction, characterized by endothelial dysfunction, low-grade inflammation and structural remodeling, plays an important role in the initiation and maintenance of essential hypertension. Although the mechanistic pathways by which essential hypertension develops are poorly understood, several pharmacological classes available on the clinical settings improve blood pressure by interfering in the cardiac output and/or vascular function. This review is divided in two major sections. The first section depicts the major molecular pathways as renin angiotensin aldosterone system (RAAS), endothelin, nitric oxide signalling pathway and oxidative stress in the development of vascular dysfunction. The second section describes the role of some pharmacological classes such as i) RAAS inhibitors, ii) dual angiotensin receptor-neprilysin inhibitors, iii) endothelin-1 receptor antagonists, iv) soluble guanylate cyclase modulators, v) phosphodiesterase type 5 inhibitors and vi) sodium-glucose cotransporter 2 inhibitors in the context of hypertension. Some classes are already approved in the treatment of hypertension, but others are not yet approved. However, due to their potential benefits these classes were included.

Neprilysin Inhibitors in Heart Failure: The Science, Mechanism of Action, Clinical Studies, and Unanswered Questions

This article provides a contemporary review and a new perspective on the role of neprilysin inhibition in heart failure (HF) in the context of recent clinical trials and addresses potential mechanisms and unanswered questions in certain HF patient populations. Neprilysin is an endopeptidase that cleaves a variety of peptides such as natriuretic peptides, bradykinin, adrenomedullin, substance P, angiotensin I and II, and endothelin. It has a broad role in cardiovascular, renal, pulmonary, gastrointestinal, endocrine, and neurologic functions. The combined angiotensin receptor and neprilysin inhibitor (ARNi) has been developed with an intent to increase vasodilatory natriuretic peptides and prevent counterregulatory activation of the angiotensin system. ARNi therapy is very effective in reducing the risks of death and hospitalization for HF in patients with HF and New York Heart Association functional class II to III symptoms, but studies failed to show any benefits with ARNi when compared with angiotensin-converting enzyme inhibitors or angiotensin receptor blocker in patients with advanced HF with reduced ejection fraction or in patients following myocardial infarction with left ventricular dysfunction but without HF. These raise the questions about whether the enzymatic breakdown of natriuretic peptides may not be a very effective solution in advanced HF patients when there is downstream blunting of the response to natriuretic peptides or among post-myocardial infarction patients in the absence of HF when there may not be a need for increased natriuretic peptide availability. Furthermore, there is a need for additional studies to determine the long-term effects of ARNi on albuminuria, obesity, glycemic control and lipid profile, blood pressure, and cognitive function in patients with HF.

The Potential Role of Serum Tau Protein (MAPT), Neuronal Cell Adhesion Molecule (NrCAM) and Neprilysin (NEP) in Neurodegenerative Disorders Development in Psoriasis-Preliminary Results

Psoriasis is one of the most common dermatoses, which shortens patients’ lives because of the wide comorbidity. However, little is known about its association with neurodegenerative diseases (NDs). We aimed to investigate whether psoriatics are at increased risk of NDs. Sixty patients with plaque-type psoriasis were enrolled into the study. Serum concentrations of tau protein (MAPT), neuronal cell adhesion molecule (NrCAM) and neprilysin (NEP), which are NDs biomarkers and have been hardly studied in psoriasis before, were measured before and after 12 weeks of treatment with acitretin or methotrexate. NrCAM and NEP concentrations were significantly lower in patients than controls, whereas MAPT higher (all p < 0.05). There was no association between these markers and psoriasis severity, BMI or disease duration. After the treatment the concentration of NrCAM and NEP significantly increased and MAPT decreased (p < 0.001, p < 0.05, p < 0.01, respectively). Methotrexate had significant influence on the concentrations of all markers, hence it seems to have neuroprotective properties. Psoriasis severity and duration do not seem to affect the risk of neurodegenerative process. Our results suggest that NDs could be considered as another comorbidity of psoriasis and that further research are needed in order to establish their definite association.

Cardio-renal benefits of sacubitril/valsartan in patients with advanced chronic kidney disease: experience in daily clinical practice

Background

The association between cardiac complications, such as heart failure (HF), and chronic kidney disease (CKD) is well known. In this study, we examined the effectiveness and safety of treatment with neprilysin inhibition in patients with advanced chronic kidney disease (stage 3b-4).

Methods

This single-centre, longitudinal, retrospective study of 31 months duration involved consecutive patients with CKD and HF with a reduced ejection fraction (HFrEF) who started treatment with sacubitril/valsartan. Glomerular filtration rate (GFR), cardiovascular risk factors, proteinuria, potassium, echocardiographic parameters and admissions for heart failure were analysed.

Results

The study comprised 25 patients with a median age of 73.2 ± 5.9 years. The most frequent aetiology of heart failure was ischemic heart disease. The median GFR was 29.4 ± 8.3 ml/min/1.73 m² and the left ventricular ejection fraction (LVEF) 36.4 ± 8.9%. The GFR improved after initiating the treatment (F = 3.396, p = 0.019), as did the LVEF at one year of follow-up (p = 0.018). The number of visits to the emergency department for heart failure was also reduced. No patients needed to start renal replacement therapy.

Conclusions

This study shows that sacubitril/valsartan may play a beneficial role in patients who have advanced CKD and HFrEF, with a satisfactory safety profile.

The role of enkephalinergic systems in substance use disorders

Enkephalin, an endogenous opioid peptide, is highly expressed in the reward pathway and may modulate neurotransmission to regulate reward-related behaviors, such as drug-taking and drug-seeking behaviors. Drugs of abuse also directly increase enkephalin in this pathway, yet it is unknown whether or not changes in the enkephalinergic system after drug administration mediate any specific behaviors. The use of animal models of substance use disorders (SUDs) concurrently with pharmacological, genetic, and molecular tools has allowed researchers to directly investigate the role of enkephalin in promoting these behaviors. In this review, we explore neurochemical mechanisms by which enkephalin levels and enkephalin-mediated signaling are altered by drug administration and interrogate the contribution of enkephalin systems to SUDs. Studies manipulating the receptors that enkephalin targets (e.g., mu and delta opioid receptors mainly) implicate the endogenous opioid peptide in drug-induced neuroadaptations and reward-related behaviors; however, further studies will need to confirm the role of enkephalin directly. Overall, these findings suggest that the enkephalinergic system is involved in multiple aspects of SUDs, such as the primary reinforcing properties of drugs, conditioned reinforcing effects, and sensitization. The idea of dopaminergic-opioidergic interactions in these behaviors remains relatively novel and warrants further research. Continuing work to elucidate the role of enkephalin in mediating neurotransmission in reward circuitry driving behaviors related to SUDs remains crucial.

Cyclic GMP modulating drugs in cardiovascular diseases: mechanism-based network pharmacology

Mechanism-based therapy centred on the molecular understanding of disease-causing pathways in a given patient is still the exception rather than the rule in medicine, even in cardiology. However, recent successful drug developments centred around the second messenger cyclic guanosine-3'-5'-monophosphate (cGMP), which is regulating a number of cardiovascular disease modulating pathways, are about to provide novel targets for such a personalized cardiovascular therapy. Whether cGMP breakdown is inhibited or cGMP synthesis is stimulated via guanylyl cyclases or their upstream regulators in different cardiovascular disease phenotypes, the outcomes seem to be so far uniformly protective. Thus, a network of cGMP-modulating drugs has evolved that act in a mechanism-based, possibly causal manner in a number of cardiac conditions. What remains a challenge is the detection of cGMPopathy endotypes amongst cardiovascular disease phenotypes. Here, we review the growing clinical relevance of cGMP and provide a glimpse into the future on how drugs interfering with this pathway may change how we treat and diagnose cardiovascular diseases altogether.

A narrative review on sacubitril/valsartan and ventricular arrhythmias

Sacubitril/valsartan, the first angiotensin receptor neprilysin inhibitor approved by the Food and Drug Administration for marketing, has been shown to reduce the risk of cardiovascular death or heart failure hospitalization and improve symptoms in patients with chronic heart failure with a reduced ejection fraction. However, some researchers have also found that sacubitril/valsartan has an antiarrhythmic effect. The mechanism by which sacubitril/valsartan reduces the mortality associated with malignant ventricular arrhythmias is not precise. Many studies have concluded that ventricular arrhythmia is associated with a reduction in myocardial fibrosis. This article reviews the current understanding of the effects of sacubitril/valsartan on the reduction of ventricular arrhythmia and explains its possible mechanisms. The results of this study suggest that sacubitril/valsartan reduces the occurrence of appropriate implantable cardioverter-defibrillator shocks. Meanwhile, sacubitril/valsartan may reduce the occurrence of ventricular arrhythmias by affecting 3 pathways of B-type natriuretic peptide, Angiotensin II, and Bradykinin. The conclusion of this study is that sacubitril/valsartan reduces the number of implantable cardioverter-defibrillator shocks and ventricular arrhythmias in heart failure with reduced ejection fraction patients.

Roles of Natriuretic Peptides and the Significance of Neprilysin in Cardiovascular Diseases

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) activate the guanylyl cyclase A receptor (GC-A), which synthesizes the second messenger cGMP in a wide variety of tissues and cells. C-type natriuretic peptide (CNP) activates the cGMP-producing guanylyl cyclase B receptor (GC-B) in chondrocytes, endothelial cells, and possibly smooth muscle cells, cardiomyocytes, and cardiac fibroblasts. The development of genetically modified mice has helped elucidate the physiological roles of natriuretic peptides via GC-A or GC-B. These include the hormonal effects of ANP/BNP in the vasculature, autocrine effects of ANP/BNP in cardiomyocytes, and paracrine effects of CNP in the vasculature and cardiomyocytes. Neprilysin (NEP) is a transmembrane neutral endopeptidase that degrades the three natriuretic peptides. Recently, mice overexpressing NEP, specifically in cardiomyocytes, revealed that local cardiac NEP plays a vital role in regulating natriuretic peptides in the heart tissue. Since NEP inhibition is a clinically accepted approach for heart failure treatment, the physiological roles of natriuretic peptides have regained attention. This article focuses on the physiological roles of natriuretic peptides elucidated in mice with GC-A or GC-B deletion, the significance of NEP in natriuretic peptide metabolism, and the long-term effects of angiotensin receptor-neprilysin inhibitor (ARNI) on cardiovascular diseases.

Comparative studies for amyloid beta degradation: “Neprilysin vs insulysin”, “monomeric vs aggregate”, and “whole Aβ40 vs its peptide fragments”

Amyloid beta (Aβ) proteins are produced from amyloid precursor protein cleaved by β- and γ-secretases, and are the main components of senile plaques pathologically found in Alzheimer's disease (AD) patient brains. Therefore, the relationship between AD and Aβs has been well studied for both therapeutic and diagnostic purposes. Several enzymes have been reported to degrade Aβs in vivo, with neprilysin (NEP) and insulysin (insulin-degrading enzyme, IDE) being the most prominent. In this article, we describe the mass spectrometric characterization of peptide fragments generated using NEP and IDE, and clarify the differences in digestion specificities between these two enzymes for non-aggregated Aβ₄₀, aggregated Aβ₄₀, and Aβ₄₀ peptide fragments, including Aβ₁₆. Our results allowed identification of all the peptide fragments from non-aggregated Aβ₄₀: NEP, 23 peptide fragments consisting of 2–11 amino-acid residues, 17 cleavage sites; IDE, 23 peptide fragments consisting of 6–33 amino-acid residues, 15 cleavage sites. Also, we confirmed that IDE can digest only whole Aβ₄₀, whereas NEP can digest both Aβ₄₀ and partial structures such as Aβ₁₆ and peptide fragments generated by the digestion of Aβ₄₀ by IDE. Furthermore, we confirmed that IDE and NEP are unable to digest aggregated Aβ₄₀.

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Two Aβ degrading enzymes (neprilysin, NEP and insulysin, IDE) were examined.

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NEP digested Aβ₄₀ into 23 peptides consisting of 2–11 amino-acid residues.

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IDE digested Aβ₄₀ into 23 peptides consisting of 6–33 amino-acid residues.

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Neither IDE nor NEP can digest aggregated Aβ₄₀.

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NEP can digest Aβ fragment peptides including Aβ₁₆, although IDE cannot.

CNP, the Third Natriuretic Peptide: Its Biology and Significance to the Cardiovascular System

Simple Summary

CNP is the third natriuretic peptide to be isolated and is widely expressed in the central nervous system, osteochondral system, and vascular system. The receptor that is mainly targeted by CNP is GC-B, which differs from GC-A, the receptor targeted by the other two natriuretic peptides, ANP and BNP. Consequently, the actions of CNP differ somewhat from those of ANP and BNP. Research into the actions of CNP has shown that CNP attenuates cardiac remodeling in animal models of cardiac hypertrophy, myocardial infarction, and myocarditis. Studies examining CNP/GC-B signaling showed that it contributes to the prevention of cardiac stiffness. Endogenous CNP, perhaps acting in part through CNP/NPR-C signaling, contributes to the regulation of vascular function and blood pressure. CNP regulates vascular remodeling and angiogenesis via CNP/GC-B/CGK signaling. CNP attenuates interstitial fibrosis and fibrosis-related gene expression in pressure overload and myocardial infarction models. The clinical application of CNP as a therapeutic agent for cardiovascular diseases is anticipated.

Abstract

The natriuretic peptide family consists of three biologically active peptides: ANP, BNP, and CNP. CNP is more widely expressed than the other two peptides, with significant levels in the central nervous system, osteochondral system, and vascular system. The receptor that is mainly targeted by CNP is GC-B, which differs from GC-A, the receptor targeted by ANP and BNP. Consequently, the actions of CNP differ somewhat from those of ANP and BNP. CNP knockout leads to severe dwarfism, and there has been important research into the role of CNP in the osteochondral system. As a result, a CNP analog is now available for clinical use in patients with achondroplasia. In the cardiovascular system, CNP and its downstream signaling are involved in the regulatory mechanisms underlying myocardial remodeling, cardiac function, vascular tone, angiogenesis, and fibrosis, among others. This review focuses on the roles of CNP in the cardiovascular system and considers its potential for clinical application in the treatment of cardiovascular diseases.

Congenital Heart Disease: The State-of-the-Art on Its Pharmacological Therapeutics

Congenital heart disease is one of the most common causes of death derived from malformations. Historically, its treatment has depended on timely diagnosis and early pharmacological and surgical interventions. Survival rates for patients with this disease have increased, primarily due to advancements in therapeutic choices, but mortality remains high. Since this disease is a time-sensitive pathology, pharmacological interventions are needed to improve clinical outcomes. Therefore, we analyzed the applications, dosage, and side effects of drugs currently used for treating congenital heart disease. Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and potassium-sparing diuretics have shown a mortality benefit in most patients. Other therapies, such as endothelin receptor antagonists, phosphodiesterase-5 inhibitors, prostaglandins, and soluble guanylyl cyclase stimulators, have benefited patients with pulmonary artery hypertension. Likewise, the adjunctive symptomatic treatment of these patients has further improved the outcomes, since antiarrhythmics, digoxin, and non-steroidal anti-inflammatory drugs have shown their benefits in these cases. Conclusively, these drugs also carry the risk of troublesome adverse effects, such as electrolyte imbalances and hemodynamic compromise. However, their benefits for survival, symptom improvement, and stabilization outweigh the possible complications from their use. Thus, cases must be assessed individually to accurately identify interventions that would be most beneficial for patients.