Sacubitril/Valsartan inhibits M1 type macrophages polarization in acute myocarditis by targeting C-type natriuretic peptide.

Studies have shown that Sacubitril/valsartan (Sac/Val) can reduce myocardial inflammation in myocarditis mice, in addition to its the recommended treatment of heart failure. However, the underlying mechanisms of Sac/Val in myocarditis remain unclear. C-type natriuretic peptide (CNP), one of the targeting natriuretic peptides of Sac/Val, was recently reported to exert cardio-protective and anti-inflammatory effects in cardiovascular systems. Here, we focused on circulating levels of CNP in patients with acute myocarditis (AMC) and whether Sac/Val modulates inflammation by targeting CNP in experimental autoimmune myocarditis (EAM) mice as well as LPS-induced RAW 264.7 cells and bone marrow derived macrophages (BMDMs) models. Circulating CNP levels were higher in AMC patients compared to healthy controls, and these levels positively correlated with the elevated inflammatory cytokines IL-6 and monocyte count. In EAM mice, Sac/Val alleviated myocardial inflammation while augmenting circulating CNP levels rather than BNP and ANP, accompanied by reduction in intracardial M1 macrophage infiltration and expression of inflammatory cytokines IL-1ß, TNF-α, and IL-6. Furthermore, Sac/Val inhibited CNP degradation and directly blunted M1 macrophage polarization in LPS-induced RAW 264.7 cells and BMDMs. Mechanistically, the effects might be mediated by the NPR-C/cAMP/JNK/c-Jun signaling pathway apart from NPR-B/cGMP/NF-κB pathway. In conclusion, Sac/Val exerts a protective effect in myocarditis by increasing CNP concentration and inhibiting M1 macrophages polarization.

Sacubitril/valsartan alleviates sunitinib-induced cardiac fibrosis and oxidative stress via improving TXNIP/TRX system and downregulation of NF-ĸB/Wnt/ß-catenin/SOX9 signaling.

We aimed in this study to investigate the possible cardioprotective effects of sacubitril/valsartan against sunitinib-induced cardiac fibrosis (CF) and oxidative stress via targeting thioredoxin-interacting protein/thioredoxin (TXNIP/TRX) system and nuclear factor-kappa B (NF-κB)/Wingless-related MMTV integration site (Wnt)/ß-catenin/Sex-determining region Y box 9 (SOX9) signaling. CF was induced in male Wistar albino rats by cumulative dose of sunitinib (300 mg/kg, given over 4 weeks as: 25 mg/kg orally, three times a week), which were co-treated with sacubitril/valsartan (68 mg/kg/day, orally) for four weeks. Significant elevation in blood pressure, cardiac inflammatory and fibrotic markers besides cardiac dysfunction were observed. These alterations were associated with disruption of TXNIP/TRX system, upregulation of NF-κB/Wnt/ß-catenin/SOX9 pathway along with marked increase in lysyl oxidase (LOX) and matrix metalloproteinase-1 (MMP-1) expressions and extensive deposition of collagen fibers in cardiac tissues. Luckily, sacubitril/valsartan was able to reverse all of the aforementioned detrimental effects in sunitinib-administered rats. These findings illustrate a potential role of sacubitril/valsartan in alleviating CF and oxidative stress induced by sunitinib via antioxidant, anti-inflammatory and antifibrotic properties. These remarkable effects of sacubitril/valsartan were mediated by its ability to improve TXNIP/TRX system and downregulate NF-κB/Wnt/ß-catenin/SOX9 signaling in addition to decreasing LOX and MMP-1 expressions in cardiac tissues. In summary, this study highlights sacubitril/valsartan as a potential therapeutic agent in mitigating CF and oxidative stress especially in cancer cases treated with sunitinib.

Angiotensin Receptor-Neprilysin Inhibition in Patients With STEMI vs NSTEMI.

BACKGROUND: Patients who sustain an acute myocardial infarction (AMI), including ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI), remain at high risk for heart failure (HF), coronary events, and death. Angiotensin-converting enzyme inhibitors have been shown to significantly decrease the risk for cardiovascular events in both STEMI and NSTEMI patients. OBJECTIVES: The objectives were to determine whether angiotensin-receptor blockade and neprilysin inhibition with sacubitril/valsartan, compared with ramipril, has impact on reducing cardiovascular events according to the type of AMI. METHODS: The PARADISE-MI (Prospective ARNI versus ACE inhibitor trial to DetermIne Superiority in reducing heart failure Events after Myocardial Infarction) trial enrolled patients with AMI complicated by left ventricular dysfunction and/or pulmonary congestion and at least 1 risk-enhancing factor. Patients were randomized to either sacubitril/valsartan or ramipril. The primary endpoint was death from cardiovascular causes or incident HF. In this prespecified analysis, we stratified patients according to AMI type. RESULTS: Of 5,661 enrolled patients, 4,291 (75.8%) had STEMI. These patients were younger and had fewer comorbidities and cardiovascular risk factors than NSTEMI patients. After adjustment for potential confounders, the risk for the primary outcome was marginally higher in NSTEMI vs STEMI patients (adjusted HR: 1.19; 95% CI: 1.00-1.41), with borderline statistical significance (P = 0.05). The primary composite outcome occurred at similar rates in patients randomized to sacubitril/valsartan vs ramipril in STEMI (10% vs 12%; HR: 0.87; 95% CI: 0.73-1.04; P = 0.13) and NSTEMI patients (17% vs 17%; HR: 0.97; 95% CI: 0.75-1.25; P = 0.80; P interaction = 0.53). CONCLUSIONS: Compared with ramipril, sacubitril/valsartan did not significantly decrease the risk for cardiovascular death and HF in patients with AMI complicated by left ventricular dysfunction, irrespective of the type of AMI. (Prospective ARNI vs ACE Inhibitor Trial to Determine Superiority in Reducing Heart Failure Events After MI; NCT02924727).

The Angiotensin II Receptor Neprilysin Inhibitor LCZ696 Inhibits the NLRP3 Inflammasome By Reducing Mitochondrial Dysfunction in Macrophages and Alleviates Dextran Sulfate Sodium-induced Colitis in a Mouse Model.

The intracellular sensor protein complex known as the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in regulating inflammatory diseases by overseeing the production of interleukin (IL)-1ß and IL-18. Targeting its abnormal activation with drugs holds significant promise for inflammation treatment. This study highlights LCZ696, an angiotensin receptor-neprilysin inhibitor, as an effective suppressor of NLRP3 inflammasome activation in macrophages stimulated by ATP, nigericin, and monosodium urate. LCZ696 also reduces caspase-11 and GSDMD activation, lactate dehydrogenase release, propidium iodide uptake, and the extracellular release of NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) in ATP-activated macrophages, suggesting a potential mitigation of pyroptosis. Mechanistically, LCZ696 lowers mitochondrial reactive oxygen species and preserves mitochondrial integrity. Importantly, it does not significantly impact NLRP3, proIL-1ß, inducible nitric oxide synthase, cyclooxygenase-2 expression, or NF-κB activation in lipopolysaccharide-activated macrophages. LCZ696 partially inhibits the NLRP3 inflammasome through the induction of autophagy. In an in vivo context, LCZ696 alleviates NLRP3-associated colitis in a mouse model by reducing colonic expression of IL-1ß and tumor necrosis factor-α. Collectively, these findings suggest that LCZ696 holds significant promise as a therapeutic agent for ameliorating NLRP3 inflammasome activation in various inflammatory diseases, extending beyond its established use in hypertension and heart failure treatment.

Pulmonary pressure-flow responses to exercise in heart failure treated with angiotensin receptor neprilysin inhibitor.

BACKGROUND: The role of the angiotensin receptor neprilysin inhibitor (ARNI) in cardiac function, particularly its impact on pulmonary circulation, remains underexplored. Recent studies have described abnormal mean pulmonary artery pressure (mPAP)-cardiac output (CO) responses as having the potential to assess the disease state. The aim of this study was to assess the effects of ARNI on pulmonary circulation in heart failure. We measured echocardiographic parameters post 6-min walk (6 MW) and compared the changes with baseline and follow-up. Our hypothesis was that pulmonary pressure-flow relationship of the pulmonary circulation obtained by 6 MW stress echocardiography would be improved with treatment. METHODS: We prospectively enrolled 39 heart failure patients and conducted the 6 MW test indoors. Post-6 MW echocardiography measured echocardiographic variables, and CO was derived from electric cardiometry. Individualized ARNI doses were optimized, with follow-up echocardiographic evaluations after 1 year. RESULTS: Left ventricular (LV) volume were significantly reduced (160.7 ± 49.6 mL vs 136.0 ± 54.3 mL, P < 0.001), and LV ejection fraction was significantly improved (37.6 ± 11.3% vs 44.9 ± 11.5%, P < 0.001). Among the 31 patients who underwent 6 MW stress echocardiographic study at baseline and 1 year later, 6 MW distance increased after treatment (380 m vs 430 m, P = 0.003). The ΔmPAP/ΔCO by 6 MW stress decreased with treatment (6.9 mmHg/L/min vs 2.8 mmHg/L/min, P = 0.002). The left atrial volume index was associated with the response group receiving ARNI treatment for pulmonary circulation. CONCLUSIONS: Initiation of ARNI was associated with improvement of left ventricular size and LVEF. Additionally, the 6 MW distance increased and the ΔmPAP/ΔCO was improved to within normal range with treatment.

Reverse Remodeling Effects of Sacubitril-Valsartan: Structural and Functional Optimization in Stage C Heart Failure.

Sacubitril-valsartan, an angiotensin receptor-neprilysin inhibitor, reduces all-cause mortality and the rate of heart failure hospitalizations in patients with heart failure with reduced ejection fraction. This study aimed to elucidate the benefits of initiating sacubitril-valsartan on ventricular remodeling in patients previously optimized on guideline-directed medical therapy. In this prospective, single-arm longitudinal study, 40 patients with heart failure with reduced ejection fraction who were optimized on guideline-directed medical therapy were transitioned to sacubitril-valsartan. The primary end point was the change in left ventricular (LV) volume at 1 year as assessed by 3-dimensional transthoracic echocardiography. Other echocardiographic end points included change in LV-function and change in right ventricular (RV) size and function. The mean age was 55 ± 12 years, and 63% were male. At 1 year, LV end-diastolic volume decreased from 242 ± 71 to 157 ± 57 ml (p <0.001) with a corresponding increase in LV ejection fraction from 32 ± 7% to 44 ± 9% (p <0.001). RV end-diastolic volume decreased from 151 ± 51 to 105 ±45 ml (p <0.001). Although RV ejection fraction did not change (51 ± 8 vs 51 ± 10; p = 0.35), RV global longitudinal strain improved from -14.9 ± 3.4 % to -19.3 ± 4.3% (p <0.001). When added to standard medical therapy for heart failure, sacubitril-valsartan induces significant remodeling of both the right and left ventricles as assessed by 3-dimensional echocardiography.

Clinical benefits of angiotensin receptor-Neprilysin inhibitor in adults with congenital heart disease.

BACKGROUND: There are limited data about the clinical benefits of angiotensin receptor-neprilysin inhibitor (ARNI) in adults with congenital heart disease (CHD). The purpose of the study was to assess the clinical benefits (chamber function and heart failure indices) of ARNI in adults with CHD. METHOD: In this retrospective cohort study, we compared the temporal change in chamber function and heart failure indices between 35 patients that received ARNI for >6 months, and a propensity matched control group (n = 70) of patients that received angiotensin converting enzyme inhibitor or angiotensin-II receptor blocker (ACEI/ARB) within the same period. RESULTS: Of the 35 patients in the ARNI group, 21 (60%) had systemic left ventricle (LV) while 14 (40%) had systemic right ventricle (RV). Compared to the ACEI/ARB group, the ARNI group had greater relative improvement in LV global longitudinal strain (GLS) (28% versus 11% increase from baseline, p < 0.001) and RV-GLS (11% versus 4% increase from baseline, p < 0.001), and greater relative improvement in New York Heart Association functional class (-14 versus -2% change from baseline, p = 0.006) and N-terminal pro-brain natriuretic peptide levels (-29% versus -13% change from baseline, p < 0.001). These results were consistent across different systemic ventricular morphologies. CONCLUSIONS: ARNI was associated with improvement in biventricular systolic function, functional status, and neurohormonal activation, suggesting prognostic benefit. These results provide a foundation for a randomized clinical trial to empirically test the prognostic benefits of ARNI in adults with CHD, as the next step towards evidence-based recommendations for heart failure management in this population.

Sacubitril/valsartan mitigates cardiac remodeling, systolic dysfunction, and preserves mitochondrial quality in a rat model of mitral regurgitation.

Sacubitril/valsartan (SAC/VAL), an angiotensin receptor blocker-neprilysin inhibitor, has been widely used to treat several types of heart failure. Nevertheless, the effects of drugs in mitral regurgitation patients, from the molecular level to therapeutic effects, remain unclear. This study investigates the roles of SAC/VAL on cardiac function, mitochondrial quality, autophagy, mitophagy, and natriuretic peptides in a rat model of chronic mitral regurgitation. Male Sprague-Dawley rats underwent MR induction (n = 16) and sham surgeries (n = 8). Four weeks post-surgery confirmed MR rats were randomly divided into MR (n = 8) and SAC/VAL (n = 8) groups. The SAC/VAL group was administered SAC/VAL, whereas the MR and the sham rats received vehicle via oral gavage daily for 8 weeks. Cardiac geometry, function, and myocardial fibrosis were assessed by echocardiography and histopathology. Spectrophotometry and real-time PCR were performed to assess the pharmacological effects on mitochondrial quality, autophagy, mitophagy, and natriuretic peptides. MR rats demonstrated significant left heart dilation and left ventricular systolic dysfunction compared with the sham group, which could be significantly improved by SAC/VAL. In addition, SAC/VAL significantly reduced myocardial cardiac remodeling and fibrosis in MR rats. SAC/VAL improved the mitochondrial quality by attenuating mitochondrial reactive oxygen species production and mitochondrial depolarization compared with the MR group. Also, the upregulation of autophagy-related, mitophagy-related, and natriuretic peptide system gene expression in MR rats was attenuated by SAC/VAL treatment. In conclusion, this study demonstrated that SAC/VAL treatment could provide numerous beneficial effects in MR conditions, suggesting that this drug may be an effective treatment for MR.

Effects of sacubitril/valsartan on exercise capacity: a prognostic improvement that starts during uptitration.

PURPOSE: Sacubitril/valsartan is a mainstay of the treatment of heart failure with reduced ejection fraction (HFrEF); however, its effects on exercise performance yielded conflicting results. Aim of our study was to evaluate the impact of sacubitril/valsartan on exercise parameters and echocardiographic and biomarker changes at different drug doses. METHODS: We prospectively enrolled consecutive HFrEF outpatients eligible to start sacubitril/valsartan. Patients underwent clinical assessment, cardiopulmonary exercise test (CPET), blood sampling, echocardiography, and completed the Kansas City Cardiomyopathy Questionnaire (KCCQ-12). Sacubitril/valsartan was introduced at 24/26 mg b.i.d. dose and progressively uptitrated in a standard monthly-based fashion to 97/103 mg b.i.d. or maximum tolerated dose. Study procedures were repeated at each titration visit and 6 months after reaching the maximum tolerated dose. RESULTS: Ninety-six patients completed the study, 73 (75%) reached maximum sacubitril/valsartan dose. We observed a significant improvement in functional capacity across all study steps: oxygen intake increased, at peak exercise (from 15.6 ± 4.5 to 16.5 ± 4.9 mL/min/kg; p trend = 0.001), while minute ventilation/carbon dioxide production relationship reduced in patients with an abnormal value at baseline. Sacubitril/valsartan induced positive left ventricle reverse remodeling (EF from 31 ± 5 to 37 ± 8%; p trend < 0.001), while NT-proBNP reduced from 1179 [610-2757] to 780 [372-1344] pg/ml (p trend < 0.0001). NYHA functional class and the subjective perception of limitation in daily life at KCCQ-12 significantly improved. The Metabolic Exercise Cardiac Kidney Index (MECKI) score progressively improved from 4.35 [2.42-7.71] to 2.35% [1.24-4.96], p = 0.003. CONCLUSIONS: A holistic and progressive HF improvement was observed with sacubitril/valsartan in parallel with quality of life. Likewise, a prognostic enhancement was observed.

Sacubitril/valsartan reduces susceptibility to atrial fibrillation by improving atrial remodeling in spontaneously hypertensive rats.

AIM: Sacubitril/valsartan (Sac/Val, LCZ696), the world's first angiotensin receptor-neprilysin inhibitor (ARNi), has been widely used in the treatment of heart failure. However, the use of Sac/Val in the treatment of atrial fibrillation (AF), especially AF with hypertension, has been less reported. We investigated the effect of Sac/Val on atrial remodeling and hypertension-related AF. METHODS: The AF induction rate and electrophysiological characteristics of spontaneously hypertensive rats (SHRs) treated with Sac/Val or Val were detected by rapid atrial pacing and electrical mapping/optical mapping. The whole-cell patch-clamp and Western blot were used to observe electrical/structural remodeling of atrial myocytes/tissue of rats and atrium-derived HL-1 cells cultured under 40 mmHg in vitro. RESULTS: Sac/Val was superior to Val in reducing blood pressure, myocardial hypertrophy and susceptibility of AF in SHRs. The shorten action potentials duration (APD), decreased L type calcium channel current (ICa,L) and Cav1.2, increased ultrarapid delayed rectified potassium current (Ikur) and Kv1.5 in atrial myocytes/tissue of SHRs could be better improved by Sac/Val, as well as the levels of atrial fibrosis. While the protein expression of angiotensin-converting enzyme-1 (ACE-1), angiotensin, angiotensin II type I AT1 receptor (AT1R) and neprilysin (NEP) were increased, which could be more effective ameliorated by Sac/Val than Val. Furthermore, Val + Sacubitrilat (LBQ657) (an active NEP inhibitor) was also superior to LBQ657 or Val in improving the electrical and structural remodeling of HL-1 cells through inhibiting NEP. CONCLUSION: Sac/Val can improve atrial structural and electrical remodeling induced by hypertension and reduce the AF susceptibility by inhibiting RAS and NEP. The above effects of Sac/Val were superior to Val alone.

Angiotensin-Neprilysin Inhibition in Patients With Mildly Reduced or Preserved Ejection Fraction and Worsening Heart Failure.

BACKGROUND: U.S. guidelines recommend consideration of sacubitril/valsartan in chronic heart failure (HF) and mildly reduced or preserved ejection fraction (EF). Whether initiation is safe and effective in EF >40% after a worsening heart failure (WHF) event is unknown. OBJECTIVES: PARAGLIDE-HF (Prospective comparison of ARNI with ARB Given following stabiLization In DEcompensated HFpEF) assessed sacubitril/valsartan vs valsartan in EF >40% following a recent WHF event. METHODS: PARAGLIDE-HF is a double-blind, randomized controlled trial of sacubitril/valsartan vs valsartan in patients with EF >40% enrolled within 30 days of a WHF event. The primary endpoint was time-averaged proportional change in amino terminal pro-B-type natriuretic peptide (NT-proBNP) from baseline through Weeks 4 and 8. A secondary hierarchical outcome (win ratio) consisted of: 1) cardiovascular death; 2) HF hospitalizations; 3) urgent HF visits; and 4) change in NT-proBNP. RESULTS: In 466 patients (233 sacubitril/valsartan; 233 valsartan), time-averaged reduction in the NT-proBNP was greater with sacubitril/valsartan (ratio of change: 0.85; 95% CI: 0.73-0.999; P = 0.049). The hierarchical outcome favored sacubitril/valsartan but was not significant (unmatched win ratio: 1.19; 95% CI: 0.93-1.52; P = 0.16). Sacubitril/valsartan reduced worsening renal function (OR: 0.61; 95% CI: 0.40-0.93) but increased symptomatic hypotension (OR: 1.73; 95% CI: 1.09-2.76). There was evidence of a larger treatment effect in the subgroup with EF ≤60% for NT-proBNP change (0.78; 95% CI: 0.61-0.98) and the hierarchical outcome (win ratio: 1.46; 95% CI: 1.09-1.95). CONCLUSIONS: Among patients with EF >40% stabilized after WHF, sacubitril/valsartan led to greater reduction in plasma NT-proBNP levels and was associated with clinical benefit compared with valsartan alone, despite more symptomatic hypotension. (Prospective comparison of ARNI with ARB Given following stabiLization In DEcompensated HFpEF; NCT03988634).

Reviewing the Modern Therapeutical Options and the Outcomes of Sacubitril/Valsartan in Heart Failure.

Sacubitril/valsartan (S/V) is a pharmaceutical strategy that increases natriuretic peptide levels by inhibiting neprilysin and regulating the renin-angiotensin-aldosterone pathway, blocking AT1 receptors. The data for this innovative medication are mainly based on the PARADIGM-HF study, which included heart failure with reduced ejection fraction (HFrEF)-diagnosed patients and indicated a major improvement in morbidity and mortality when S/V is administrated compared to enalapril. A large part of the observed favorable results is related to significant reverse cardiac remodeling confirmed in two prospective trials, PROVE-HF and EVALUATE-HF. Furthermore, according to a subgroup analysis from the PARAGON-HF research, S/V shows benefits in HFrEF and in many subjects having preserved ejection fraction (HFpEF), which indicated a decrease in HF hospitalizations among those with a left ventricular ejection fraction (LVEF) < 57%. This review examines the proven benefits of S/V and highlights continuing research in treating individuals with varied HF characteristics. The article analyses published data regarding both the safeness and efficacy of S/V in patients with HF, including decreases in mortality and hospitalization, increased quality of life, and reversible heart remodeling. These benefits led to the HF guidelines recommendations updating and inclusion of S/V combinations a key component of HFrEF treatment.

Comparative Effect of Angiotensin Receptor Neprilysin Inhibition on B-type Natriuretic Peptide Levels Measured by Three Different Assays: The PROVE-HF Study.

BACKGROUND: Several different B-type natriuretic peptide (BNP) assays are used clinically for diagnostic and prognostic evaluation of heart failure (HF). BNP binds weakly to neprilysin and is cleaved in multiple areas adjacent to the binding sites for the antibodies used in these immunoassays. We assessed the changes in BNP following neprilysin inhibition as measured by 3 immunoassays that recognize different epitopes. METHODS: Among 130 participants with HF with reduced ejection fraction, blood was collected prior to treatment with sacubitril/valsartan (sac/val) and then repeatedly measured through 52 weeks of treatment. BNP concentrations were measured with 3 widely used BNP assays (Siemens, Abbott, and Quidel). RESULTS: Study participants had a mean age of 65 ± 13 years and 76% were men. The median BNP concentration at baseline was 133 ng/L by the Siemens assay, 127 ng/L by the Abbott assay, and 141 ng/L by the Quidel assay. Following initiation of sac/val, there were significantly greater declines in BNP measured by Quidel and Abbott (P = 0.009 and P < 0.001), respectively (both with N-terminal capture antibodies), compared to Siemens (with C-terminal capture antibodies). The difference from baseline was not statistically significant until after week 12 (mean -10.1% for Quidel and -14.3% for Abbott) compared to non-significant differences before 12 weeks (mean -4.5% for Quidel and -6.0% for Abbott). CONCLUSIONS: Following initiation of sac/val, BNP measurements may modestly differ depending on the assay method used, particularly after a few months of treatment. Whether these differences relate to neprilysin-mediated degradation of antibody binding sites deserves further study. STUDY REGISTRATION: PROVE-HF ClinicalTrials.gov Identifier: NCT02887183.

The glutamate/GABA system in the retina of male rats: effects of aging, neurodegeneration, and supplementation with melatonin and antioxidant SkQ1.

Glutamate and -aminobutyric acid (GABA) are the most abundant amino acids in the retina. An imbalance of the glutamate/GABA system is involved in the pathogenesis of various neurodegenerative disorders. Here we for the first time analyzed alterations of expression of glutamate- and GABA-synthesizing enzymes, transporters, and relevant receptors in the retina with age in Wistar rats and in senescence-accelerated OXYS rats who develop AMD-like retinopathy. We noted consistent age-dependent expression changes of GABAergic-system proteins (GAD67, GABA-T, and GAT1) in OXYS and Wistar rats: upregulation by age 3 months and downregulation at age 18 months. At a late stage of AMD-like retinopathy in OXYS rats (18 months), there was significant upregulation of glutaminase and downregulation of glutamine synthetase, possibly indicating an increasing level of glutamate in the retina. AMD-like-retinopathy development in the OXYS strain was accompanied by underexpression of glutamate transporter GLAST. Prolonged supplementation with both melatonin and SkQ1 (separately) suppressed the progression of the AMD-like pathology in OXYS rats without affecting the glutamate/GABA system but worsened the condition of the Wistar rat's retina during normal aging. We observed decreasing protein levels of glutamine synthetase, GLAST, and GABAAR1 and an increasing level of glutaminase in Wistar rats. In summary, both melatonin and mitochondrial antioxidant SkQ1 had different effect on the retinal glutamate / GABA in healthy Wistar and senescence-accelerated OXYS rats.

Insulinotropic Effects of Neprilysin and/or Angiotensin Receptor Inhibition in Mice.

Treatment of heart failure with the angiotensin receptor-neprilysin inhibitor sacubitril/valsartan improved glycemic control in individuals with type 2 diabetes. The relative contribution of neprilysin inhibition versus angiotensin II receptor antagonism to this glycemic benefit remains unknown. Thus, we sought to determine the relative effects of the neprilysin inhibitor sacubitril versus the angiotensin II receptor blocker valsartan on beta-cell function and glucose homeostasis in a mouse model of reduced first-phase insulin secretion, and whether any beneficial effects are additive/synergistic when combined in sacubitril/valsartan. High fat-fed C57BL/6J mice treated with low-dose streptozotocin (or vehicle) were followed for eight weeks on high fat diet alone or supplemented with sacubitril, valsartan or sacubitril/valsartan. Body weight and fed glucose levels were assessed weekly. At the end of the treatment period, insulin release in response to intravenous glucose, insulin sensitivity, and beta-cell mass were determined. Sacubitril and valsartan, but not sacubitril/valsartan, lowered fasting and fed glucose levels and increased insulin release in diabetic mice. None of the drugs altered insulin sensitivity or beta-cell mass, but all reduced body weight gain. Effects of the drugs on insulin release were reproduced in angiotensin II-treated islets from lean C57BL/6J mice, suggesting the insulin response to each of the drugs is due to a direct effect on islets and mechanisms therein. In summary, sacubitril and valsartan each exert beneficial insulinotropic, glycemic and weight-reducing effects in obese and/or diabetic mice when administered alone; however, when combined, mechanisms within the islet contribute to their inability to enhance insulin release.

Angiotensin receptor-neprilysin inhibitors for hypertension-hemodynamic effects and relevance to hypertensive heart disease.

Angiotensin receptor-neprilysin inhibitors have multiple beneficial effects on the cardiovascular system. The angiotensin receptor-neprilysin inhibitor sacubitril/valsartan has been shown to effectively reduce ambulatory 24-h blood pressure in patients with hypertension, and improvements in many aspects of hemodynamic function have also been reported. Overall hemodynamic effects on arterial stiffness and nocturnal blood pressure play an important role in the pathogenesis of hypertensive heart disease. Therefore, these could represent mechanistic targets underlying the effects of angiotensin receptor-neprilysin inhibitors on the continuum of cardiovascular disease from hypertension to heart failure. Other potential mechanisms include reductions in circulating volume and sympathetic activity, both of which contribute to the protection against target organ damage and positive changes in cardiac biomarkers seen during angiotensin receptor-neprilysin inhibitor therapy. The mechanisms of action and beneficial effects of angiotensin receptor-neprilysin inhibitors are complementary to those of a number of other treatment options for hypertension, suggesting the possibility of additive or even synergistic benefits. Based on available data, there are a number of patient groups who will benefit from antihypertensive treatment with an angiotensin receptor-neprilysin inhibitor, including those with salt-sensitive hypertension, structural hypertension, resistant hypertension, and hypertension in the presence of heart failure. Overall, angiotensin receptor-neprilysin inhibitors regulate blood pressure and pulse pressure via multiple mechanisms and provide cardiovascular protection. This provides an option for effective intervention early in the vicious cycle of elevated blood pressure and central pressures with progression toward heart failure that should help to address the growing worldwide heart failure epidemic.

Valsartan and sacubitril combination treatment enhances collagen production in older adult human skin cells.

Collagen is a major component of the skin's support system, allowing for its firmness, elasticity, and mechanical strength. Skin collagen production decreases as we age and is associated with increased sagging, wrinkling, and thinning. The Renin-Angiotensin System (RAS) is a key hormonal system that changes with age and affects multiple organ systems. The primary health benefits of Angiotensin (Ang) receptor type1 (AT1R) blockers are believed to arise from systemic effects on blood pressure. However, there is also a skin-specific RAS, though this system has been less well characterized. There are eight FDA-approved angiotensin receptor blockers (ARBs) on the market, although the impact of topical ARBs on aging skin is unknown. Here, we evaluated the topical penetration of gel formulations of eight ARBs using human cadaver skin. Our results show that valsartan achieved the highest skin penetration compared to other ARBs. We then treated human skin fibroblasts from 2-year-old and 57-year-old individuals with valsartan alone or in combination with the neprilysin inhibitor sacubitril. Sacubitril works synergistically with valsartan by inhibiting the degradation of angiotensin II, thereby increasing its bioavailability. Treatment of young and older adult human skin cells with valsartan and sacubitril led to a five-fold increase in collagen type-1 production in the young cells and a four-fold increase in collagen type-1 in older adult cells. This study demonstrates a potential novel application for the widely prescribed drug combination sacubitril-valsartan as a topical agent in aged skin.

Angiotensin receptor-neprilysin inhibitor attenuates cardiac hypertrophy and improves diastolic dysfunction in a mouse model of heart failure with preserved ejection fraction.

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