Prevention against renal damage in rats with subtotal nephrectomy by sacubitril/valsartan (LCZ696), a dual-acting angiotensin receptor-neprilysin inhibitor

Sacubitril/valsartan ameliorates tubulointerstitial fibrosis by restoring mitochondrial homeostasis in diabetic kidney disease

BACKGROUND

Tubulointerstitial fibrosis plays an important role in the progression of diabetic kidney disease (DKD). Sacubitril/valsartan (Sac/Val) exerts a robust beneficial effect in DKD. However, the potential functional effect of Sac/Val on tubulointerstitial fibrosis in DKD is still largely unclear.

METHODS

Streptozotocin-induced diabetic mice were given Sac/Val or Val by intragastric administration once a day for 12 weeks. The renal function, the pathological changes of tubule injury and tubulointerstitial fibrosis, as well as mitochondrial morphology of renal tubules in mice, were evaluated. Genome-wide gene expression analysis was performed to identify the potential mechanisms. Meanwhile, human tubular epithelial cells (HK-2) were cultured in high glucose condition containing LBQ657/valsartan (LBQ/Val). Further, mitochondrial functions and Sirt1/PGC1α pathway of tubular epithelial cells were assessed by Western blot, Real-time-PCR, JC-1, MitoSOX or MitoTracker. Finally, the Sirt1 specific inhibitor, EX527, was used to explore the potential effects of Sirt1 signaling in vivo and in vitro.

RESULTS

We found that Sac/Val significantly ameliorated the decline of renal function and tubulointerstitial fibrosis in DKD mice. The enrichment analysis of gene expression indicated metabolism as an important modulator in DKD mice with Sac/Val administration, in which mitochondrial homeostasis plays a pivotal role. Then, the decreased expression of Tfam and Cox IV;, as well as changes of mitochondrial function and morphology, demonstrated the disruption of mitochondrial homeostasis under DKD conditions. Interestingly, Sac/Val administration was found to restore mitochondrial homeostasis in DKD mice and in vitro model of HK-2 cells. Further, we demonstrated that Sirt1/PGC1α, a crucial pathway in mitochondrial homeostasis, was activated by Sac/Val both in vivo and in vitro. Finally, the beneficial effects of Sac/Val on mitochondrial homeostasis and tubulointerstitial fibrosis was partially abolished in the presence of Sirt1 specific inhibitor.

CONCLUSIONS

Taken together, we demonstrate that Sac/Val ameliorates tubulointerstitial fibrosis by restoring Sirt1/PGC1α pathway-mediated mitochondrial homeostasis in DKD, providing a theoretical basis for delaying the progression of DKD in clinical practice.

Protective effect of novel angiotensin receptor neprilysin inhibitor S086 on target organ injury in spontaneously hypertensive rats

BACKGROUND

Hypertension is a clinical syndrome characterized by elevated systemic arterial blood pressure associated with injury to the heart, kidney, brain, and other organs. Angiotensin receptor neprilysin inhibitors (ARNi), including angiotensin receptor blockers (ARBs) and neprilysin inhibitors (NEPi), have been shown to be safe and effective at reducing blood pressure and alleviating development of target organ injury. This study was used to develop S086 as a novel ARNi and conducted preclinical studies in animal models to evaluate the protective effects of S086 on target organs.

METHODS

This study used a 14-month-old spontaneously hypertensive rat (SHR) model to evaluate the protective effects of S086 on the cardiovascular system and organs such as heart and kidney by blood pressure monitoring, urine and blood examination, pathological examination, and immunological index detection.

RESULTS

After administering S086 orally to the SHR, their blood pressure and levels of renal injury indicators such as serum creatinine and urinary microalbumin were reduced, and myocardial cell necrosis and cardiac fibrosis of the heart were significantly improved. In addition, there were also significantly improvements in the histological lesions of blood vessels and the kidneys.

CONCLUSIONS

The findings showed that S086 effectively reduced the blood pressure of SHR and had effects on alleviating development of heart, blood vessels and kidney.

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.

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.

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

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

Effects of Sacubitril/Valsartan on the Renal Resistance Index

Background: Sacubitril/valsartan plays a key role in improving left ventricular remodeling and prognosis in patients with heart failure with a reduced ejection fraction (HFrEF). Moreover, some data support its role in preserving renal function. In order to better clarify the effects of sacubitril/valsartan in cardiorenal syndrome, this study evaluated its effects on the renal resistance index (RRI). Methods: A group of patients with HFrEF was enrolled. The RRI was assessed with renal echo-color Doppler at enrollment and again after at least six months of sacubitril/valsartan treatment. In a subgroup of patients, the RRI was also evaluated at least six months before enrollment. The variations in echocardiographic parameters reflecting the left and right ventricular function, as well as creatinine and the estimated glomerular filtration rate, were also evaluated. Results: After treatment with sacubitril/valsartan, significant improvements in the left ventricular ejection fraction, and a decrease in the left atrial and ventricular volumes were observed. The RRI also showed a significant decrease. No relationship was found between the improvements in the parameters reflecting cardiac function and changes in the RRI. Conclusions: Treatment with sacubitril/valsartan is associated with improvements in both left ventricular function and renal perfusion, through decreasing the renal resistance. These data help to clarify the effects of the drug on cardiorenal syndrome progression.

LCZ696 Ameliorates Isoproterenol-Induced Acute Heart Failure in Rats by Activating the Nrf2 Signaling Pathway

Objective

LCZ696 (sacubitril/valsartan) is an angiotensin II (Ang II) type 1 receptor-neprilysin inhibitor, with effects of immunosuppression, anti-inflammation, antiapoptosis, and antioxidation. The present study was aimed at determining whether LCZ696 has a protective effect against isoproterenol-induced acute heart failure (AHF) in rats.

Methods

SD rats were randomly divided into four groups: control group, HF group, LCZ696 group, and enalapril group. The cardiac function of rats was evaluated using echocardiographic parameters, heart weight (HW), serum levels of cardiac troponin I (cTnI), and lactate dehydrogenase (LDH). HE is staining, which was used to determine the pathological damage of rat myocardial tissue. Also, we measured oxidative stress markers including reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT). Finally, the expression of Nrf2 signaling pathway-related proteins was determined using Western blot.

Results

Compared with the HF group, LCZ696 could significantly improve cardiac function and myocardial injury in rats and reduce AHF-induced oxidative stress. In addition, the results of Western blot confirmed that LCZ696 could upregulate the expression of Nrf2 and HO-1 while decreasing Keap1 expression.

Conclusion

LCZ696 ameliorates isoproterenol-induced AHF in rats by alleviating oxidative stress injury and activating the Nrf2 signaling pathway.

Potential effects and application prospect of angiotensin receptor-neprilysin inhibitor in diabetic kidney disease

Diabetic kidney disease (DKD) is one of the main causes of end-stage renal disease (ESRD) and all-cause mortality in diabetic patients, despite the extensive use of angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II receptor blocker (ARB). Angiotensin receptor-neprilysin inhibitor (ARNI), combining ARB and neutral endopeptidase inhibitor (NEPI), is likely to have potential favorable effects in DKD. This review summarizes existing preclinical and clinical studies on mechanism of ARNI and its potential effects on DKD. In preclinical studies, ARNI manifested its renoprotective effects by improving natriuresis, ameliorating inflammation, oxidative stress and renal dysfunction, and slowing down glomerulosclerosis and tubulointerstitial injury of kidney, but its effect on proteinuria is still controversial. Beneficial effects of ARNI on blood glucose regulation and glycometabolism have also been reported. There are no clinical studies of ARNI that specifically focus on DKD patients so far. ARNI has application potential in DKD, but there still need clinical studies that focus on DKD patients to determine its effectiveness, safety and underlying mechanism.

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

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

The effects of sacubitril/valsartan on heart failure with preserved ejection fraction: a meta-analysis

BACKGROUND

Compared with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, Sacubitril/Valsartan has been reported to have superior results. However, the effects of sacubitril/valsartan on heart failure with preserved ejection fraction (HFpEF) are still in dispute.

OBJECTIVES

This study aims to evaluate the effects of sacubitril/valsartan on the treatment of HFpEF patients.

METHODS

PubMed, Embase, Web of Science, Cochrane Library, and Clinicaltrials.gov were used to search for randomised controlled trials of sacubitril/valsartan in HFpEF patients from inception to 7 December 2020.

RESULTS

Four studies, with a total of 7739 participants, met the inclusion criteria. The present meta-analysis results showed that compared with the control group, sacubitril/valsartan reduced the hospitalisation rate of HF in HFpEF patients [Risk Ratio(RR): 0.85; 95% confidence interval (CI): 0.79-0.93; p = 0.0002). Regarding all-cause mortality, cardiovascular mortality, and the improvement in NYHA class, sacubitril/valsartan did not show apparent advantages. Although sacubitril/valsartan was linked to increasing the risk of symptomatic hypotension (RR: 1.44; 95% CI: 1.25-1.66; p﹤0.00001), there was no evidence supporting the incidence of renal function worsening and hyperkalemia.

CONCLUSION

Our study shows that compared with valsartan or individualised medical therapy (IMT), there were not different between the two groups except for the hospitalisation rate which was favoured by Sacubitril/Valsartan treatment group for HFpEF patients.

Broadening COVID-19 Interventions to Drug Innovation: Neprilysin Pathway as a Friend, Foe, or Promising Molecular Target?

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is anticipated to transition to an endemic state as vaccines are providing relief in some, but not all, countries. Drug discovery for COVID-19 can offer another tool in the fight against the pandemic. Additionally, COVID-19 impacts multiple organs that call for a systems medicine approach to planetary health and therapeutics innovation. In this context, innovation for drugs that prevent and treat COVID-19 is timely and much needed. As the virus variants emerge under different ecological conditions and contexts in the long haul, a broad array of vaccine and drug options will be necessary. This expert review article argues for a need to expand the COVID-19 interventions, including and beyond vaccines, to stimulate discovery and development of novel medicines against SARS-CoV-2 infection. The Renin-Angiotensin-Aldosterone System (RAAS) is known to play a major role in SARS-CoV-2 infection. Neprilysin (NEP) and angiotensin-converting enzyme (ACE) have emerged as the pharmaceutical targets of interest in the search for therapeutic interventions against COVID-19. While the NEP/ACE inhibitors offer promise for repurposing against COVID-19, they may display a multitude of effects in different organ systems, some beneficial, and others adverse, in modulating the inflammation responses in the course of COVID-19. This expert review offers an analysis and discussion to deepen our present understanding of the pathophysiological function of neprilysin in multiple organs, and the possible effects of NEP inhibitor-induced inflammatory responses in COVID-19-infected patients.

Sacubitril/valsartan in chronic kidney disease: From pharmacological mechanism to clinical application

Chronic kidney disease (CKD) is an irreversible, progressive disease characterized by persistent kidney damage, and significantly increased risks of cardiovascular event. However, therapeutic strategies to prevent or slow the progression of CKD remain limited. Sacubitril/valsartan (LCZ696), the representative of the first novel angiotensin receptor-neprilysin inhibitor, has been incorporated into clinical practice guidelines for improving outcomes as a milestone in patients with heart failure. Considering the complex and close relationship between CKD and heart failure, LCZ696 may be beneficial in the treatment of CKD. This review summarizes the pharmacological mechanism and clinical application of LCZ696 in patients with CKD, including its effect on cardiovascular risk and renal outcome, together with potential adverse events. Additionally, due to the influence of serum creatinine and estimated glomerular filtration rate on LCZ696 in patients with heart failure, we also discussed the effects of LCZ696 in patients with advanced CKD and end-stage renal disease. It should be noted that, current clinical studies on LCZ696 are mostly carried out in patients with heart failure, and renal indicators are selected as secondary outcomes. Therefore, more researches should be conducted in patients with CKD alone in the future, to determine the efficacy and safety of LCZ696 in patients with CKD.

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

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

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

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

The effect of neprilysin and renin inhibition on the renal dysfunction following ischemia-reperfusion injury in the rat

The natriuretic peptide (NP) system counter-regulates the renin-angiotensin system (RAS), so enhancing the activity of natriuretic peptides (NPs) may be beneficial in conditions when RAS is activated such as ischemia-reperfusion injury (IRI). Neprilysin is the key enzyme responsible for the degradation of NPs. The effects of neprilysin inhibition or the combination of neprilysin inhibition and RAS inhibition on renal IRI-induced renal dysfunction have not been investigated yet. To investigate this, rats underwent sham surgery or bilateral IRI for 20 min. G-Als, G-Scb, and G-Als+Scb underwent similar protocol but received aliskiren (renin inhibitor), sacubitril (neprilysin inhibitor) or a combination of both pre- and post-IRI, respectively. IRI caused significant alterations in all renal functional parameters, markers of acute renal injury, pro-inflammatory and pro-fibrotic cytokines, and histological features. All these alterations were significantly attenuated in G-Als, G-Scb, and G-Als+Scb. The attenuations in the alterations in serum creatinine, creatinine clearance, and histological features were larger in G-Als+Scb compared to either G-Als or G-Scb. We conclude that RAS blockade by a renin inhibitor (aliskiren) or neprilysin inhibition by sacubitril separately led to significant attenuation in the renal IRI-induced renal dysfunction. The combination of aliskiren and sacubitril was more effective than either one alone.

Repurposing of existing FDA approved drugs for Neprilysin inhibition: An in-silico study

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Drug repurposing of FDA approved drugs from ZINC 12 database was done using the crystal structure of extracellular domain of human NEP (PDB ID: 5JMY)

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The interactions with catalytic triad of HIS583, HIS587 and GLU646 are important for NEP inhibition.

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Based on XP molecular docking, binding energy, IFD-SP and MD simulation top 4 NEP inhibitors were identified.

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ZINC000000601283 and ZINC000003831594 were found to be stable during MD simulation and may act as NEP inhibitors.

Neprilysin (NEP) is a neutral endopeptidase with diverse physiological roles in the body. NEP's role in degradation of diverse classes of peptides such as amyloid beta, natriuretic peptide, substance P, angiotensin, endothelins, etc., is associated with pathologies of alzheimer's, kidney and heart diseases, obesity, diabetes and certain malignancies. Hence, the functional inhibition of NEP in the above systems can be a good therapeutic target. In the present study, in-silico drug repurposing approach was used to identify NEP inhibitors. Molecular docking was carried out using GLIDE tool. 2934 drugs from the ZINC12 database were screened using high throughput virtual screening (HTVS) followed by standard precision (SP) and extra precision (XP) docking. Based on the XP docking score and ligand interaction, the top 8 hits were subjected to free ligand binding energy calculation, to filter out 4 hits (ZINC000000001427, ZINC000001533877, ZINC000000601283, and ZINC000003831594). Further, induced fit docking-standard precision (IFD-SP) and molecular dynamics (MD) studies were performed. The results obtained from MD studies suggest that ZINC000000601283-NEP and ZINC000003831594-NEP complexes were most stable for 20ns simulation period as compared to ZINC000001533877-NEP and ZINC000000001427-NEP complexes. Interestingly, ZINC000000601283 and ZINC000003831594 showed similarity in binding with the reported NEP inhibitor sacubitrilat. Findings from this study suggest that ZINC000000601283 and ZINC000003831594 may act as NEP inhibitors. In future studies, the role of ZINC000000601283 and ZINC000003831594 in NEP inhibition should be tested in biological systems to evaluate therapeutic effect in NEP associated pathological conditions.

Differential effects of low-dose sacubitril and/or valsartan on renal disease in salt-sensitive hypertension

Diuretics and renin-angiotensin system blockers are often insufficient to control the blood pressure (BP) in salt-sensitive (SS) subjects. Abundant data support the proposal that the level of atrial natriuretic peptide may correlate with the pathogenesis of SS hypertension. We hypothesized here that increasing atrial natriuretic peptide levels with sacubitril, combined with renin-angiotensin system blockage by valsartan, can be beneficial for alleviation of renal damage in a model of SS hypertension, the Dahl SS rat. To induce a BP increase, rats were challenged with a high-salt 4% NaCl diet for 21 days, and chronic administration of vehicle or low-dose sacubitril and/or valsartan (75 μg/day each) was performed. Urine flow, Na+ excretion, and water consumption were increased on the high-salt diet compared with the starting point (0.4% NaCl) in all groups but remained similar among the groups at the end of the protocol. Upon salt challenge, we observed a mild decrease in systolic BP and urinary neutrophil gelatinase-associated lipocalin levels (indicative of alleviated tubular damage) in the valsartan-treated groups. Sacubitril, as well as sacubitril/valsartan, attenuated the glomerular filtration rate decline induced by salt. Alleviation of protein cast formation and lower renal medullary fibrosis were observed in the sacubitril/valsartan- and valsartan-treated groups, but not when sacubitril alone was administered. Interestingly, proteinuria was mildly mitigated only in rats that received sacubitril/valsartan. Further studies of the effects of sacubitril/valsartan in the setting of SS hypertension, perhaps involving a higher dose of the drug, are warranted to determine if it can interfere with the progression of the disease.

Effects of Low-Dose Sacubitril/Valsartan on Different Stages of Cardiac Hypertrophy in Salt-Loaded Hypertensive Rats

BACKGROUND

Sacubitril/valsartan was shown to attenuate the development of cardiac hypertrophy with enhanced blood pressure reduction compared with valsartan alone in animal models. We investigated whether a low-dose sacubitril/valsartan has blood pressure-independent effects on cardiac hypertrophy and pulmonary edema using a rat model of hypertension and obesity.

METHODS AND RESULTS

In plan 1, male SHR/NDmcr-cp rats fed normal or phase-increased high salt were treated with vehicle, 6-mg/kg sacubitril/valsartan or 3-mg/kg valsartan, for 6 months. In plan 2, after high-salt loading for 6 months, drugs were administered for 4 months. Antihypertensive effects of the 2 drugs were similar during all study periods. In plan 1 with normal salt, there were no differences between treatments in the left ventricle weight/body weight (BW), or lung weight/BW as an index of cardiac hypertrophy or pulmonary edema, respectively. These indexes were smaller in high-salt-fed rats with sacubitril/valsartan than vehicle. In plan 2, both indexes did not differ between vehicle and sacubitril/valsartan. Ventricle weight/BW was lower in valsartan than sacubitril/valsartan. In plan 2, gene markers of cardiac dysfunction were upregulated by sacubitril/valsartan compared with the other groups.

CONCLUSIONS

Low-dose sacubitril/valsartan may have different effects depending on the stage of cardiac hypertrophy in rats.

Telmisartan and thiorphan combination treatment attenuates fibrosis and apoptosis in preventing diabetic cardiomyopathy

Aims

LCZ696, a first-generation dual angiotensin receptor-neprilysin inhibitor (ARNi), is effective in treating heart failure patients. However, the role of ARNis in treating diabetic cardiomyopathy is poorly understood. This study evaluates the efficacy of a novel combination of telmisartan [angiotensin receptor blocker (ARB)] and thiorphan [neprilysin inhibitor (NEPi)] in ameliorating diabetic cardiomyopathy while, at the same time, exploring the relevant underlying molecular mechanism(s).

Methods and results

Diabetes was induced by administration of streptozotocin (55 mg/kg, i.p.) in male Wistar rats. After 4 weeks, diabetic rats were subjected to either thiorphan (0.1 mg/kg/day, p.o.) or telmisartan (10 mg/kg/day, p.o.) monotherapy, or their combination, for a period of 4 weeks. Metabolic and morphometric alterations, failing ventricular functions, and diminished baroreflex indicated development of diabetic cardiac complications. Apart from morphometric alterations, all pathological consequences were prevented by telmisartan and thiorphan combination therapy. Diabetic rats exhibited significant modulation of the natriuretic peptide system, a key haemodynamic regulator; this was normalized by combination therapy. Histopathological studies showed augmented myocardial fibrosis, demonstrated by increased % PSR-positive area, with combination therapy giving the best improvement in these indices. More importantly, the combination of thiorphan and telmisartan was superior in attenuating inflammatory (NF-κB/MCP-1), profibrotic (TGF-β/Smad7) and apoptotic (PARP/Caspase-3) cascades compared to respective monotherapies when treating rats with diabetic cardiomyopathy. In addition, diabetic heart chromatin was in a state of active transcription, indicated by increased histone acetylation (H2AK5Ac, H2BK5Ac, H3K9Ac, and H4K8Ac) and histone acetyltransferase (PCAF and Ac-CBP) levels. Interestingly, combination treatment was sufficiently potent to normalize these alterations.

Conclusion

The protective effect of novel ARB and NEPi combination against diabetic cardiomyopathy can be attributed to inhibition of inflammatory, profibrotic, and apoptotic cascades. Moreover, reversal of histone acetylation assists its protective effect.

The angiotensin II receptor-neprilysin inhibitor LCZ696 attenuates the progression of proteinuria in type 2 diabetic rats

We examined the effects of the angiotensin receptor-neprilysin inhibitor LCZ696 on overt proteinuria and renal injury in type 2 diabetic Otsuka-Long- Evans-Tokushima-Fatty (OLETF) rats. Aged OLETF rats were also treated with either valsartan or valsartan plus hydralazine for comparison. LCZ696 caused greater attenuation of the progression of proteinuria than either valsartan alone or valsartan combined with hydralazine. Reduced glomerular injury and tubulointerstitial fibrosis were also observed in LCZ696-treated rats. Moreover, LCZ696 prevented increases in blood urea nitrogen (BUN) and creatinine levels. These data suggest that LCZ696 elicits a reno-protective effect against type 2 diabetes with overt proteinuria.

Neprilysin, the kidney brush border neutral proteinase: a possible potential target for ischemic renal injury

Neprilysin (NEP) is an endogenously induced peptidase for modulating production and degradation of various peptides in humans. It is most abundantly present in kidney and regulates the intrinsic renal homeostatic mechanism. Recently, drugs inhibiting NEP have been approved for the use in heart failure. In the context of increased prevalence of ischemia associated renal failure, NEP could be an attractive target for treating kidney failure. In the kidney, targeting NEP may possess potential benefits as well as adverse consequences. The unfavorable outcomes of NEP are mainly attributed to the degradation of the natriuretic peptides (NPs). NPs are involved in the inhibition of the renin-angiotensin-aldosterone system (RAAS) and activation of the sympathetic system contributing to the tubular and glomerular injury. In contrary, NEP exerts the beneficial effect by converting angiotensin-1 (Ang I) to angiotensin-(1-7) (Ang-(1-7)), thus activating MAS-related G-protein coupled receptor. MAS receptor antagonizes angiotensin type I receptor (AT-1R), reduces reactive oxygen species (ROS) and inflammation, thus ameliorating renal injury. However, the association of NEP with complex cascades of renal ischemia remains vague. Therefore, there is a need to evaluate the putative mechanism of NEP and its overlap with other signaling cascades in conditions of renal ischemia.

Effects of Sacubitril/Valsartan Versus Irbesartan in Patients With Chronic Kidney Disease

BACKGROUND

Sacubitril/valsartan reduces the risk of cardiovascular mortality among patients with heart failure with reduced ejection fraction, but its effects on kidney function and cardiac biomarkers in people with moderate to severe chronic kidney disease are unknown.

METHODS

The UK HARP-III trial (United Kingdom Heart and Renal Protection-III), a randomized double-blind trial, included 414 participants with an estimated glomerular filtration rate (GFR) 20 to 60 mL/min/1.73 m² who were randomly assigned to sacubitril/valsartan 97/103 mg twice daily versus irbesartan 300 mg once daily. The primary outcome was measured GFR at 12 months using ANCOVA with adjustment for each individual's baseline measured GFR. All analyses were by intention to treat.

RESULTS

In total, 207 participants were assigned to sacubitril/valsartan and 207 to irbesartan. Baseline measured GFR was 34.0 (SE, 0.8) and 34.7 (SE, 0.8) mL/min/1.73 m², respectively. At 12 months, there was no difference in measured GFR: 29.8 (SE 0.5) among those assigned sacubitril/valsartan versus 29.9 (SE, 0.5) mL/min/1.73 m² among those assigned irbesartan; difference, -0.1 (0.7) mL/min/1.73 m². Effects were similar in all prespecified subgroups. There was also no significant difference in estimated GFR at 3, 6, 9, or 12 months and no clear difference in urinary albumin:creatinine ratio between treatment arms (study average difference, -9%; 95% CI, -18 to 1). However, compared with irbesartan, allocation to sacubitril/valsartan reduced study average systolic and diastolic blood pressure by 5.4 (95% CI, 3.4-7.4) and 2.1 (95% CI, 1.0-3.3) mm Hg and levels of troponin I and N terminal of prohormone brain natriuretic peptide (tertiary end points) by 16% (95% CI, 8-23) and 18% (95% CI, 11-25), respectively. The incidence of serious adverse events (29.5% versus 28.5%; rate ratio, 1.07; 95% CI, 0.75-1.53), nonserious adverse reactions (36.7% versus 28.0%; rate ratio, 1.35; 95% CI, 0.96-1.90), and potassium ≥5.5 mmol/L (32% versus 24%, P=0.10) was not significantly different between randomized groups.

CONCLUSIONS

Over 12 months, sacubitril/valsartan has similar effects on kidney function and albuminuria to irbesartan, but it has the additional effect of lowering blood pressure and cardiac biomarkers in people with chronic kidney disease.

CLINICAL TRIAL REGISTRATION

URL: http://www.isrctn.com . Unique identifier: ISRCTN11958993.

Interaction Between Sacubitril and Valsartan in Preventing Heart Failure Induced by Aortic Valve Insufficiency in Rats

BACKGROUND

Synergistic interactions between neprilysin inhibition (NEPi) with sacubitril and angiotensin receptor type1 blockade (ARB) with valsartan have been implicated in improvement of left ventricular (LV) contractility, relaxation, exercise tolerance, and fibrosis in preexisting heart failure (HF) induced by aortic valve insufficiency (AVI). It is not known whether this pharmacologic synergy can prevent cardiovascular pathology in a similar AVI model. Our aim was to investigate the pharmacology of sacubitril/valsartan in an experimental setting with therapy beginning immediately after creation of AVI.

METHODS

HF was induced through partial disruption of the aortic valve in rats. Therapy began 3 hours after valve disruption and lasted 8 weeks. Sacubitril/valsartan (68 mg/kg), valsartan (31 mg/kg), sacubitril (31 mg/kg), or vehicle were administered daily via oral gavage (N=8 in each group). Hemodynamic assessments were conducted using Millar technology, and an exercise tolerance test was conducted using a rodent treadmill.

RESULTS

Only sacubitril/valsartan increased total arterial compliance and ejection fraction (EF). Therapies with sacubitril/valsartan and valsartan similarly improved load-dependent (dP/dt_max) and load independent indices (Ees) of LV contractility, and exercise tolerance, whereas sacubitril did not. None of the therapies improved LV relaxation (dP/dt_min), whereas all reduced myocardial fibrosis.

CONCLUSIONS

1) The synergistic interaction between NEPi and ARB in early therapy with sacubitril/valsartan leads to increased total arterial compliance and EF. 2) Improvement in indices of LV contractility, and exercise tolerance with sacubitril/valsartan is likely because of ARB effect of valsartan. 3) All three therapies provided antifibrotic effects, suggesting both ARB and NEPi are capable of reducing myocardial fibrosis.

The combination of a neprilysin inhibitor (sacubitril) and angiotensin-II receptor blocker (valsartan) attenuates glomerular and tubular injury in the Zucker Obese rat

OBJECTIVE

Diabetic nephropathy (DN) is characterized by glomerular and tubulointerstitial injury, proteinuria and remodeling. Here we examined whether the combination of an inhibitor of neprilysin (sacubitril), a natriuretic peptide-degrading enzyme, and an angiotensin II type 1 receptor blocker (valsartan), suppresses renal injury in a pre-clinical model of early DN more effectively than valsartan monotherapy.

METHODS

Sixty-four male Zucker Obese rats (ZO) at 16 weeks of age were distributed into 4 different groups: Group 1: saline control (ZOC); Group 2: sacubitril/valsartan (sac/val) (68 mg kg^-1 day^-1; ZOSV); and Group 3: valsartan (val) (31 mg kg^-1 day^-1; ZOV). Group 4 received hydralazine, an anti-hypertensive drug (30 mg kg^-1 day^-1, ZOH). Six Zucker Lean (ZL) rats received saline (Group 5) and served as lean controls (ZLC). Drugs were administered daily for 10 weeks by oral gavage.

RESULTS

Mean arterial pressure (MAP) increased in ZOC (+ 28%), but not in ZOSV (- 4.2%), ZOV (- 3.9%) or ZOH (- 3.7%), during the 10 week-study period. ZOC were mildly hyperglycemic, hyperinsulinemic and hypercholesterolemic. ZOC exhibited proteinuria, hyperfiltration, elevated renal resistivity index (RRI), glomerular mesangial expansion and podocyte foot process flattening and effacement, reduced nephrin and podocin expression, tubulointerstitial and periarterial fibrosis, increased NOX2, NOX4 and AT₁R expression, glomerular and tubular nitroso-oxidative stress, with associated increases in urinary markers of tubular injury. None of the drugs reduced fasting glucose or HbA1c. Hypercholesterolemia was reduced in ZOSV (- 43%) and ZOV (- 34%) (p < 0.05), but not in ZOH (- 13%) (ZOSV > ZOV > ZOH). Proteinuria was ameliorated in ZOSV (- 47%; p < 0.05) and ZOV (- 30%; p > 0.05), but was exacerbated in ZOH (+ 28%; p > 0.05) (ZOSV > ZOV > ZOH). Compared to ZOC, hyperfiltration was improved in ZOSV (p < 0.05 vs ZOC), but not in ZOV or ZOH. None of the drugs improved RRI. Mesangial expansion was reduced by all 3 treatments (ZOV > ZOSV > ZOH). Importantly, sac/val was more effective in improving podocyte and tubular mitochondrial ultrastructure than val or hydralazine (ZOSV > ZOV > ZOH) and this was associated with increases in nephrin and podocin gene expression in ZOSV (p < 0.05), but not ZOV or ZOH. Periarterial and tubulointerstitial fibrosis and nitroso-oxidative stress were reduced in all 3 treatment groups to a similar extent. Of the eight urinary proximal tubule cell injury markers examined, five were elevated in ZOC (p < 0.05). Clusterin and KIM-1 were reduced in ZOSV (p < 0.05), clusterin alone was reduced in ZOV and no markers were reduced in ZOH (ZOSV > ZOV > ZOH).

CONCLUSIONS

Compared to val monotherapy, sac/val was more effective in reducing proteinuria, renal ultrastructure and tubular injury in a clinically relevant animal model of early DN. More importantly, these renoprotective effects were independent of improvements in blood pressure, glycemia and nitroso-oxidative stress. These novel findings warrant future clinical investigations designed to test whether sac/val may offer renoprotection in the setting of DN.

Potential Uses of Sacubitril/Valsartan: Need for Data on Efficacy and Safety

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have been the cornerstone for the treatment of heart failure (HF) with reduced ejection fraction for decades. According to recent and promising studies, sacubitril/valsartan (SV) might be efficient in alternative indications in the area of HF with preserved left ventricular ejection fraction, chronic kidney disease, and so on. This review briefly summarizes these promising therapeutic options regarding SV and the potential limits and pitfalls for its use in routine practice (due to cognitive uncertainties).

Vascular and Neural Complications in Type 2 Diabetic Rats: Improvement by Sacubitril/Valsartan Greater Than Valsartan Alone

Previously, we had shown that a vasopeptidase inhibitor drug containing ACE and neprilysin inhibitors was an effective treatment for diabetic vascular and neural complications. However, side effects prevented further development. This led to the development of sacubitril/valsartan, a drug containing angiotensin II receptor blocker and neprilysin inhibitor that we hypothesized would be an effective treatment for diabetic peripheral neuropathy. Using early and late intervention protocols (4 and 12 weeks posthyperglycemia, respectively), type 2 diabetic rats were treated with valsartan or sacubitril/valsartan for 12 weeks followed by an extensive evaluation of vascular and neural end points. The results demonstrated efficacy of sacubitril/valsartan in improving vascular and neural function was superior to valsartan alone. In the early intervention protocol, sacubitril/valsartan treatment was found to slow progression of these deficits and, with late intervention treatment, was found to stimulate restoration of vascular reactivity, motor and sensory nerve conduction velocities, and sensitivity/regeneration of sensory nerves of the skin and cornea in a rat model of type 2 diabetes. These preclinical studies suggest that sacubitril/valsartan may be an effective treatment for diabetic peripheral neuropathy, but additional studies will be needed to investigate these effects further.

FAVORABLE EFFECT OF LEVOTHYROXINE ON NUTRITIONAL STATUS OF PATIENTS WITH STAGE 3-4 CHRONIC KIDNEY DISEASE

The aim of this study was to analyze the incidence of malnutrition in patients with stage 3-4 chronic kidney disease (CKD) and primary subclinical hypothyroidism and the effect of levothyroxine for improving nutritional status and delaying kidney disease.

PATIENTS AND METHODS

In the study were included 200 patients with stage 3-4 CKD: CKD3 stage group (n=100) and CKD4 stage group (n=100). These patients were further divided into: control group (non-treatment group) group a (n=65) and experiment group (treatment group) group b (n=135) according to their levothyroxine treatment. The CKD3 stage group is divided into c3 (n=35) and e3 (n=65), and CKD4 group is divided into c4 (n=30) and e4 (n=70) groups.

RESULTS

Upon treatment of subclinical hypothyroidism with levothyroxine, nutritional indicators of patients are improved, and the weight, left and right-hand grip strength, hemoglobin (HB), serum albumin are higher compared to control. After levothyroxine treatment, eGFR in the treatment group increased with each time point, while in the control group it could be seen a significant decrease. This effect was more robust in the CKD3 group than in the CKD4 group. In conclusion, levothyroxine treatment can delay the progression of kidney diseases with more efficacy in stage 3 patients.

The probable roles of valsartan in alleviating chronic obstructive pulmonary disease following co-exposure to cold stress and fine particulate matter

Angiotensin II (ANG II) might play an important role in the co-effects of cold stress and fine particulate matter (PM_2.5) on chronic obstructive pulmonary disease (COPD). The purpose of this study is to evaluate the roles of valsartan in alleviating COPD following co-exposure to cold stress and PM_2.5. Both the two intervention factors are carried out upon COPD rats with the intervention of valsartan. Blockade of angiotensin receptor by valsartan decreases the levels of malondialdehyde in the normal temperature and tumor necrosis factor-α under cold stress significantly. When treated with valsartan and PM_2.5 simultaneously, the expression of 8-hydroxy-2-deoxyguanosine, nuclear factor kappa B and heme oxygenase-1 decrease significantly in the group of cold stress. In conclusion, these results indicate that valsartan might relieve the co-effects of cold stress and PM_2.5 on COPD rat lung to some degree.

Prevention against renal damage in rats with subtotal nephrectomy by sacubitril/valsartan (LCZ696), a dual-acting angiotensin receptor-neprilysin inhibitor

Although patients with chronic kidney disease (CKD) are at increased risk for end‐stage renal disease and cardiovascular events, adequate drug therapies for preventing the deterioration of these conditions are still not established. This study was undertaken to evaluate a preventive effect of an angiotensin receptor‐neprilysin inhibitor sacubitril/valsartan (LCZ696), which is converted to sacubitril and valsartan in the body, against the progression of renal disease in rats with subtotal nephrectomy, an animal model of human CKD. Mean survival time after subtotal nephrectomy was about 100 days in Wistar rats with vehicle. LCZ696‐(30 mg/kg) and valsartan‐(15 mg/kg) prolonged the survival of these animals, and the effect of LCZ696 on survival was significantly greater than that of valsartan. Renoprotective effects of LCZ696 judged by serum creatinine and urinary protein excretions were larger than those of valsartan. Cardioprotective effects judged by cardiac left ventricular mass, fractional shortening, and fibrosis of LCZ696 and valsartan were not detected under the present condition. Thus, the renoprotective effect of LCZ696 was stronger than that of valsartan in rats with subtotal nephrectomy. This study provides the idea that, compared to valsartan, LCZ696 is more effective for the treatment of human CKD.