Protection of Sacubitril/Valsartan against Pathological Cardiac Remodeling by Inhibiting the NLRP3 Inflammasome after Relief of Pressure Overload in Mice

Sacubitril/valsartan ameliorates cardiac function and ventricular remodeling in CHF rats via the inhibition of the tryptophan/kynurenine metabolism and inflammation

Sacubitril/valsartan has been highly recognized as a treatment for Chronic heart failure (CHF). Its potential cardioprotective benefits and mechanisms, however, remain to be explored. Metabolomics can be used to identify the metabolic characteristics and related markers, as well as the influence of drugs, thereby opening up the new mechanism for sacubitril/valsartan therapy in CHF disease. In this study, the ligation of left anterior descending and exhaustive swimming were used to induce a rat model of CHF after myocardial infarction. The efficacy was appraised with echocardiography, serum NT-proBNP, and histopathologica. UPLC-Q/TOF-MS combined with multivariate statistical analysis approach were used to analyze the effect of sacubitril/valsartan on CHF rats. RT-qPCR and western blot were performed to investigate the tryptophan/kynurenine metabolism pathway. Accordingly, the basal cardiac function were increased, while the serum NT-proBNP and collagen volume fraction decreased in CHF rats with sacubitril/valsartan. Sacubitril/valsartan regulated the expression of kynurenine et.al 8 metabolomic biomarkers in CHF rats serum, and it contributed to the cardioprotective effects through tryptophan metabolism pathway. In addition, the mRNA and protein expression of the indoleamine 2,3-dioxygenase (IDO) in the myocardial tissue of CHF rats, were down-regulated by sacubitril/valsartan, which was the same with the IL-1β, IFN-γ, TNF-α, COX-2, and IL-6 mRNA expression, and IL-1β, IFN-γ, and TNF-α expression in serum. In conclusion, sacubitril/valsartan can ameliorate cardiac function and ventricular remodeling in CHF rats, at least in part through inhibition of tryptophan/kynurenine metabolism.

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)-1β 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-1β, 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-1β 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.

Possible role of LCZ696 in atherosclerosis: new inroads and perspective

LCZ696 blocks both angiotensin receptor type 1 (ATR1) and neprilysin (NEP), which are intricate in the degradation of natriuretic peptides (NPs) and other endogenous peptides. It has been shown NEP inhibitors and LCZ696 could be effectively in the management of atherosclerosis (AS). However, the underlying mechanism of LCZ696 in AS is needed to be clarified entirely. Hence, this review is directed to reconnoiter the mechanistic role of LCZ696 in AS. The anti-inflammatory role of LCZ696 is related to the inhibition of transforming growth factor beta (TGF-β)-activated kinase 1 (TAK) and nod-like receptor pyrin 3 receptor (NLRP3) inflammasome. Moreover, LCZ696, via inhibition of pro-inflammatory cytokines, oxidative stress, apoptosis and endothelial dysfunction can attenuate the development and progression of AS. In conclusion, LCZ696 could be effective in the management of AS through modulation of inflammatory and oxidative signaling. Preclinical and clinical studies are recommended in this regard.

Discovery of a novel 1,3,4-oxadiazol-2-one-based NLRP3 inhibitor as a pharmacological agent to mitigate cardiac and metabolic complications in an experimental model of diet-induced metaflammation

Inspired by the recent advancements in understanding the binding mode of sulfonylurea-based NLRP3 inhibitors to the NLRP3 sensor protein, we developed new NLRP3 inhibitors by replacing the central sulfonylurea moiety with different heterocycles. Computational studies evidenced that some of the designed compounds were able to maintain important interaction within the NACHT domain of the target protein similarly to the most active sulfonylurea-based NLRP3 inhibitors. Among the studied compounds, the 1,3,4-oxadiazol-2-one derivative 5 (INF200) showed the most promising results being able to prevent NLRP3-dependent pyroptosis triggered by LPS/ATP and LPS/MSU by 66.3 ± 6.6% and 61.6 ± 11.5% and to reduce IL-1β release (35.5 ± 8.8% μM) at 10 μM in human macrophages. The selected compound INF200 (20 mg/kg/day) was then tested in an in vivo rat model of high-fat diet (HFD)-induced metaflammation to evaluate its beneficial cardiometabolic effects. INF200 significantly counteracted HFD-dependent "anthropometric" changes, improved glucose and lipid profiles, and attenuated systemic inflammation and biomarkers of cardiac dysfunction (particularly BNP). Hemodynamic evaluation on Langendorff model indicate that INF200 limited myocardial damage-dependent ischemia/reperfusion injury (IRI) by improving post-ischemic systolic recovery and attenuating cardiac contracture, infarct size, and LDH release, thus reversing the exacerbation of obesity-associated damage. Mechanistically, in post-ischemic hearts, IFN200 reduced IRI-dependent NLRP3 activation, inflammation, and oxidative stress. These results highlight the potential of the novel NLRP3 inhibitor, INF200, and its ability to reverse the unfavorable cardio-metabolic dysfunction associated with obesity.

LCZ696 (sacubitril/valsartan) mitigates cyclophosphamide-induced premature ovarian failure in rats; the role of TLR4/NF-κB/NLRP3/Caspase-1 signaling pathway

AIM

Cyclophosphamide (CP) is used to treat a variety of cancers and autoimmune illnesses. CP has been found to frequently cause premature ovarian failure (POF). The study's objective was to assess LCZ696's potential for protection against CP-induced POF in a rat model.

MAIN METHODS

Rats were randomly assigned into seven groups as follows: control, valsartan (VAL), LCZ696, CP, CP + VAL, CP + LCZ696, and CP + triptorelin (TRI). Ovarian malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD), interleukin-18 (IL-18), IL-1β, and tumor necrosis factor-alpha (TNF-α) were assessed using ELISA. Serum anti-mullerian hormone (AMH), estrogen, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were also measured using ELISA. The expression of NLRP3/Caspase-1/GSDMD C-NT and TLR4/MYD88/NF-B P65 proteins was estimated using western blot assay. The histopathology of the ovaries was also investigated. The estrous cycle, body, and ovarian weights were also monitored.

KEY FINDINGS

CP treatment significantly elevated levels of MDA, IL-18, IL-1β, TNF-α, FSH, LH, and up-regulated TLR4/NF-κB/NLRP3/Caspase-1 proteins, as compared to the control group, however, ovarian follicles count, and levels of GSH, SOD, AMH, and estrogen were reduced with CP administration. All the aforementioned biochemical and histological abnormalities were considerably alleviated by the LCZ696 therapy compared to valsartan alone.

SIGNIFICANCE

LCZ696 effectively mitigated CP-induced POF, offering promising protection that could be related to its suppression power on NLRP3-induced pyroptosis and TLR4/NF-B P65 pathway.

Neprilysin Inhibition in the Prevention of Anthracycline-Induced Cardiotoxicity

Anthracycline-induced cardiotoxicity (AIC) poses a clinical challenge in the management of cancer patients. AIC is characterized by myocardial systolic dysfunction and remodeling, caused by cardiomyocyte DNA damage, oxidative stress, mitochondrial dysfunction, or renin-angiotensin-aldosterone system (RAAS) dysregulation. In the past decade, after positive results of a PARADIGM-HF trial, a new class of drugs, namely angiotensin receptor/neprilysin inhibitors (ARNi), was incorporated into the management of patients with heart failure with reduced ejection fraction. As demonstrated in a variety of preclinical studies of cardiovascular diseases, the cardioprotective effects of ARNi administration are associated with decreased oxidative stress levels, the inhibition of myocardial inflammatory response, protection against mitochondrial damage and endothelial dysfunction, and improvement in the RAAS imbalance. However, data on ARNi's effectiveness in the prevention of AIC remains limited. Several reports of ARNi administration in animal models of AIC have shown promising results, as ARNi prevented ventricular systolic dysfunction and electrocardiographic changes and ameliorated oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and the inflammatory response associated with anthracyclines. There is currently an ongoing PRADAII trial aimed to assess the efficacy of ARNi in patients receiving breast cancer treatment, which is expected to be completed by late 2025.

Pyroptosis is a drug target for prevention of adverse cardiac remodeling: The crosstalk between pyroptosis, apoptosis, and autophagy

Acute myocardial infarction (AMI) is one of the main reasons of cardiovascular disease-related death. The introduction of percutaneous coronary intervention to clinical practice dramatically decreased the mortality rate in AMI. Adverse cardiac remodeling is a serious problem in cardiology. An increase in the effectiveness of AMI treatment and prevention of adverse cardiac remodeling is difficult to achieve without understanding the mechanisms of reperfusion cardiac injury and cardiac remodeling. Inhibition of pyroptosis prevents the development of postinfarction and pressure overload-induced cardiac remodeling, and mitigates cardiomyopathy induced by diabetes and metabolic syndrome. Therefore, it is reasonable to hypothesize that the pyroptosis inhibitors may find a role in clinical practice for treatment of AMI and prevention of cardiac remodeling, diabetes and metabolic syndrome-triggered cardiomyopathy. It was demonstrated that pyroptosis interacts closely with apoptosis and autophagy. Pyroptosis could be inhibited by nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 inhibitors, caspase-1 inhibitors, microRNA, angiotensin-converting enzyme inhibitors, angiotensin Ⅱ receptor blockers, and traditional Chinese herbal medicines.

The protective effect of LCZ696 in coxsackievirus B3-induced acute viral myocarditis mice

AIMS

Acute viral myocarditis (AVMC) is the aetiology of heart failure (HF) with few specific treatments. The improvement of left ventricular ejection fraction (LVEF) is a critical predictor for the prognosis of AVMC. LCZ696 is a drug used in HF to improve LVEF, with a few research on AVMC. In this research, we evaluated the effects and mechanism of LCZ696 in improving LVEF in AVMC.

METHODS

Eighty 4-week-old male BALB/c mice were randomly divided into four groups of 20: Sham; Sham + LCZ696 (60 mg/kg/d); AVMC; AVMC + LCZ696. The above experiments were repeated by CVB3-infected HL-1 and Mdivi-1 to down-regulated dynamin-related protein 1(Drp1). Adeno-associated virus 9 (AAV9) with enhanced green fluorescent proteins (GFP) was injected to produce Drp1-overexpression mice and set up four groups: AVMC group, AVMC + AAV group, AVMC + LCZ696 group, and AVMC + LCZ696 + AAV group (n = 20 in each group). LVEF was evaluated by echocardiography at a similar heart rate (HR) at d7, Drp1 (p-Drp1), inflammation and apoptosis by histology and Western blot (WB), and mitochondrial by electron microscopy.

RESULTS

Cardiac function were injured in AVMC that LCZ696 reversed (LVEF, %: Sham: 68.99 ± 9.67; Sham + LCZ696: 71.96 ± 6.20; AVMC: 30.95 ± 6.40*; AVMC + LCZ696: 68.99 ± 9.67*#, *P < 0.05 vs. Sham, #P < 0.05 vs. AVMC). LCZ696 attenuated p-Drp1 expression, inflammation, apoptosis, and mitochondrial fission (p-Drp1/Drp1: Sham: 1; Sham + LCZ696: 1.37 ± 0.22; AVMC: 2.29 ± 0.36*; AVMC+LCZ696: 1.43 ± 0.08*#, *P < 0.05 vs. Sham, #P < 0.05 vs. AVMC). Some of the above results were repeated in CVB3-infected HL-1 cells and Mdivi-1. AAV increased Drp1 expression and mitochondrial fission, inflammatory, and apoptosis. Compared with the AVMC + AAV group, the LVEF increased from 24.44 ± 0.03% to 32.33 ± 0.05% in the AVMC + LCZ696 + AAV group(P < 0.05), p-Drp1/Drp1 decreased from 0.54 ± 0.12 to 0.42 ± 0.09*, and IL-6, c-IL-1β, and c-caspase-3/caspase-3 decreased from 1.07 ± 0.22 to 0.72 ± 0.08*, from 1.03 ± 0.14 to 0.79 ± 0.09*, and from 4.69 ± 0.29 to 0.92 ± 0.13*, respectively (*P < 0.05).

CONCLUSIONS

LCZ696 has a protective effect on AVMC by improving LVEF and reducing inflammation and apoptosis, which may be due to the inhibition of Drp1-mediated mitochondrial fission.

Molecular mechanisms of sacubitril/valsartan in cardiac remodeling

Cardiovascular diseases have become a major clinical burden globally. Heart failure is one of the diseases that commonly emanates from progressive uncontrolled hypertension. This gives rise to the need for a new treatment for the disease. Sacubitril/valsartan is a new drug combination that has been approved for patients with heart failure. This review aims to detail the mechanism of action for sacubitril/valsartan in cardiac remodeling, a cellular and molecular process that occurs during the development of heart failure. Accumulating evidence has unveiled the cardioprotective effects of sacubitril/valsartan on cellular and molecular modulation in cardiac remodeling, with recent large-scale randomized clinical trials confirming its supremacy over other traditional heart failure treatments. However, its molecular mechanism of action in cardiac remodeling remains obscure. Therefore, comprehending the molecular mechanism of action of sacubitril/valsartan could help future research to study the drug’s potential therapy to reduce the severity of heart failure.

Up-regulation of Nrf2/HO-1 and inhibition of TGF-β1/Smad2/3 signaling axis by daphnetin alleviates transverse aortic constriction-induced cardiac remodeling in mice

Oxidative damage and accumulation of extracellular matrix (ECM) components play a crucial role in the adverse outcome of cardiac hypertrophy. Evidence suggests that nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) can modulate oxidative damage and adverse myocardial remodeling. Daphnetin (Daph) is a coumarin obtained from the plant genus Daphne species that exerts anti-oxidative and anti-inflammatory properties. Herein, we investigated the roles of Daph in transverse aortic constriction (TAC)-induced cardiac hypertrophy and fibrosis in mice. TAC-induced alterations in cardiac hypertrophy markers, histopathological changes, and cardiac function were markedly ameliorated by oral administration of Daph in mice. We found that Daph significantly reduced the reactive oxygen species (ROS) generation, increased the nuclear translocation of Nrf2, and consequently, reinstated the protein levels of NAD(P)H quinone dehydrogenase1 (NQO1), heme oxygenase-1 (HO-1), and other antioxidants in the heart. Besides, Daph significantly inhibited the TAC-induced accumulation of ECM components, including α-smooth muscle actin (α-SMA), collagen I, collagen III, and fibronectin, and interfered with the TGF-β1/Smad2/3 signaling axis. Further studies revealed that TAC-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive nuclei and the protein levels of Bax/Bcl2 ratio and cleaved caspase 3 were substantially decreased by Daph treatment. We further characterized the effect of Daph on angiotensin II (Ang-II)-stimulated H9c2 cardiomyoblast cells and observed that Daph markedly decreased the Ang-II induced increase in cell size, production of ROS, and proteins associated with apoptosis and fibrosis. Mechanistically, Daph alone treatment enhanced the protein levels of Nrf2, NQO1, and HO-1 in H9c2 cells. The inhibition of this axis by Si-Nrf2 transfection abolished the protective effect of Daph in H9c2 cells. Taken together, Daph effectively counteracted the TAC-induced cardiac hypertrophy and fibrosis by improving the Nrf2/HO-1 axis and inhibiting the TGF-β1/Smad2/3 signaling axis.

Sacubitril/valsartan protects against arsenic trioxide induced cardiotoxicity in vivo and in vitro

The cardiotoxicity induced by arsenic trioxide (ATO) limits its clinical application in acute promyelocytic leukemia treatment. Sacubitril/valsartan (LCZ696) is an effective drug for the treatment of heart failure. In this study, we aimed to investigate the protective effect and mechanisms of LCZ696 against the ATO-induced cardiotoxicity in mice and H9c2 cells. We found that LCZ696 could alleviate the decrease of ejection fraction and fractional shortening induced by ATO, thereby improving mouse cardiac contractile function. LCZ696 could also reduce the myocardial enzyme, resist oxidative stress, mitigate myocardial fibrosis, and ameliorate myocardial structure, thereby alleviating myocardial damage caused by ATO. In addition, LCZ696 could significantly increase the cell viability and reduce the accumulation of reactive oxygen species in ATO-treated H9c2 cells. Besides, in vivo and in vitro studies have been found that LCZ696 could restore the expression of Bcl-2 and reduce Bax and Caspase-3 levels, inhibiting ATO-induced apoptosis. Meanwhile, LCZ696 decreased the levels of IL-1, IL-6, and TNF-α, alleviating the inflammatory injury caused by ATO. Furthermore, LCZ696 prevented NF-κB upregulation induced by ATO. Our findings revealed that LCZ696 has a considerable effect on preventing cardiotoxicity induced by ATO, which attributes to its capability to suppress oxidative stress, inflammation, and apoptosis.

MCC950, a Selective NLRP3 Inhibitor, Attenuates Adverse Cardiac Remodeling Following Heart Failure Through Improving the Cardiometabolic Dysfunction in Obese Mice

Obesity is often accompanied by hypertension. Although a large number of studies have confirmed that NLRP3 inhibitors can improve cardiac remodeling in mice with a normal diet, it is still unclear whether NLRP3 inhibitors can improve heart failure (HF) induced by pressure overload in obese mice. The purpose of this study was to explore the role of MCC950, a selective NLRP3 inhibitor, on HF in obese mice and its metabolic mechanism. Obese mice induced with a 10-week high-fat diet (HFD) were used in this study. After 4 weeks of HFD, transverse aortic constriction (TAC) surgery was performed to induce a HF model. MCC950 (10 mg/kg, once/day) was injected intraperitoneally from 2 weeks after TAC and continued for 4 weeks. After echocardiography examination, we harvested left ventricle tissues and performed molecular experiments. The results suggest that in obese mice, MCC950 can significantly improve cardiac hypertrophy and fibrosis caused by pressure overload. MCC950 ameliorated cardiac inflammation after TAC surgery and promoted M2 macrophage infiltration in the cardiac tissue. MCC950 not only restored fatty acid uptake and utilization by regulating the expression of CD36 and CPT1β but also reduced glucose uptake and oxidation via regulating the expression of GLUT4 and p-PDH. In addition, MCC950 affected the phosphorylation of AKT and AMPK in obese mice with HF. In summary, MCC950 can alleviate HF induced by pressure overload in obese mice via improving cardiac metabolism, providing a basis for the clinical application of NLRP3 inhibitors in obese patients with HF.

Arterial Hypertension in Aortic Valve Stenosis: A Critical Update

Aortic stenosis (AS) is a very common valve disease and is associated with high mortality once it becomes symptomatic. Arterial hypertension (HT) has a high prevalence among patients with AS leading to worse left ventricle remodeling and faster degeneration of the valve. HT also interferes with the assessment of the severity of AS, leading to an underestimation of the real degree of stenosis. Treatment of HT in AS has not historically been pursued due to the fear of excess reduction in afterload without a possibility of increasing stroke volume due to the fixed aortic valve, but most recent evidence shows that several drugs are safe and effective in reducing BP in patients with HT and AS. RAAS inhibitors and beta-blockers provide benefit in selected populations based on their profile of pharmacokinetics and pharmacodynamics. Different drugs, on the other hand, have proved to be unsafe, such as calcium channel blockers, or simply not easy enough to handle to be recommended in clinical practice, such as PDE5i, MRA or sodium nitroprusside. The present review highlights all available studies on HT and AS to guide antihypertensive treatment.

Selective Inhibition of NLRP3 Inflammasome Reverses Pressure Overload-Induced Pathological Cardiac Remodeling by Attenuating Hypertrophy, Fibrosis, and Inflammation

Activation of the NLRP3 inflammasome promotes pathological cardiac remodeling induced by pressure overload. However, the therapeutic effects of NLRP3 inhibition after cardiac remodeling remain unknown. The present study aimed to investigate whether the selective NLRP3 inhibitor, MCC950, could reverse transverse aortic constriction (TAC)-induced cardiac remodeling. Mice were divided into four groups based on the treatment given: sham, sham + MCC950, TAC, and TAC + MCC950. MCC950 (10 mg/kg, intraperitoneal injection, once per day) was administered from two weeks after TAC or sham surgery for four weeks. Echocardiography, histological analysis, RT-PCR, and Western blotting were performed to explore the function of MCC950 after TAC. We found that MCC950 reversed cardiac dysfunction after TAC. MCC950 attenuated cardiac hypertrophy by down-regulating calcineurin expression and inhibiting MAPK activation. Further, it also alleviated cardiac fibrosis post-TAC by inhibiting the TGF-β/Smad4 pathway, and reduced cardiac inflammation and macrophage infiltration post-TAC, including both M1 and M2 macrophages. Taken together, MCC950 can attenuate cardiac remodeling due to pressure overload by inhibiting hypertrophy, fibrosis, and inflammation. Our study provides a basis for the clinical application of NLRP3 inhibitors in the treatment of non-ischemic heart failure.

Xinyang Tablet inhibits MLK3-mediated pyroptosis to attenuate inflammation and cardiac dysfunction in pressure overload

ETHNOPHARMACOLOGICAL RELEVANCE

Xinyang tablet (XYT) has been traditionally used in the treatment of cardiovascular diseases (CVDs). Our previous study indicated that XYT exhibited protective effects in heart failure (HF).

AIM OF THE STUDY

The aim of the present study was to determine the protective effects of XYT in pressure overload induced HF and to elucidate its underlying mechanisms of action.

MATERIALS AND METHODS

We analyzed XYT content using high-performance liquid chromatography (HPLC.). Mice were subjected to transverse aortic constriction (TAC) to generate pressure overload-induced cardiac remodeling and were then orally administered XYT or URMC-099 for 1 week after the operation. HL1 mouse cardiomyoblasts were induced by lipopolysaccharides (LPS) to trigger pyroptosis and were then treated with XYT or URMC-099. We used echocardiography (ECG), hematoxylin and eosin (H&E) staining, Masson's trichrome staining and a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay to evaluate the effects of XYT. Messenger ribonucleic acid (mRNA) levels of collagen metabolism biomarkers and inflammation-related factors were detected. We determined protein levels of inflammation- and pyroptosis-related signaling pathway members via Western blot (WB). Caspase-1 activity was measured in cell lysate using a Caspase-1 Activity Assay Kit. Subsequently, to define the candidate ingredients in XYT that regulate mixed-lineage kinase-3 (MLK3), we used molecular docking (MD) to predict and evaluate binding affinity with MLK3. Finally, we screened 24 active potential compounds that regulate MLK3 via MD.

RESULTS

ECG, H&E staining, Masson's trichrome staining and TUNEL assay results showed that XYT remarkably improved heart function, amelorated myocardial fibrosis and inhibited apoptosis in vivo. Moreover, it reduced expression of proteins or mRNAs related to collagen metabolism, including collagen type 1 (COL1), fibronectin (FN), alpha smooth-muscle actin (α-SMA), and matrix metalloproteinases-2 and -9 (MMP-2, MMP-9). XYT also inhibited inflammation and the induction of pyroptosis at an early stage, as well as attenuated inflammation and pyroptosis levels in vitro.

CONCLUSION

Our data indicated that XYT exerted protective effects against pressure overload induced myocardial fibrosis (MF), which might be associated with the induction of pyroptosis-mediated MLK3 signaling.

Sacubitril/Valsartan Decreases Atrial Fibrillation Susceptibility by Inhibiting Angiotensin II-Induced Atrial Fibrosis Through p-Smad2/3, p-JNK, and p-p38 Signaling Pathways

Sacubitril/valsartan (SAC/VAL) prevents angiotensin II (AngII) from binding AT1-R and blocks degradation of natriuretic peptides. Despite its efficacy in reducing ventricular fibrosis and preserving cardiac functions, which has been extensively demonstrated in myocardial infarction or pressure overload models, few studies have been conducted to determine whether SAC/VAL could attenuate atrial fibrosis and decrease atrial fibrillation (AF) susceptibility. Our study provided evidence for the inhibition of atrial fibrosis and reduced susceptibility to AF by SAC/VAL. After 28 days of AngII continuous subcutaneous stimulation, rats in SAC/VAL group exhibited reduced extent of atrial fibrosis, inhibited proliferation, migration, and differentiation of atrial fibroblasts, and decreased susceptibility to AF. We further found that inhibition of p-Smad2/3, p-JNK, and p-p38MAPK pathways is involved in the role of SAC/VAL on AngII-induced atrial fibrosis in vivo. These results emphasize the importance of SAC/VAL in the prevention of AngII-induced atrial fibrosis and may help to enrich the options for AF pharmacotherapy.

Therapeutic Assessment of Combination Therapy with a Neprilysin Inhibitor and Angiotensin Type 1 Receptor Antagonist on Angiotensin II-Induced Atherosclerosis, Abdominal Aortic Aneurysms, and Hypertension

Combined neprilysin (NEP) inhibition (sacubitril) and angiotensin type 1 receptor (AT1R) antagonism (valsartan) is used in the treatment of congestive heart failure and is gaining interest for other angiotensin II (AngII)-related cardiovascular diseases. In addition to heart failure, AngII promotes hypertension, atherosclerosis, and abdominal aortic aneurysms (AAAs). Similarly, NEP substrates or products have broad effects on the cardiovascular system. In this study, we examined NEP inhibition (with sacubitril) and AT1R antagonism (with valsartan) alone or in combination on AngII-induced hypertension, atherosclerosis, or AAAs in male low-density lipoprotein receptor-deficient mice. Preliminary studies assessed drug delivery via osmotic minipumps for simultaneous release of sacubitril and/or valsartan with AngII over 28 days. Mice were infused with AngII (1000 ng/kg per minute) in the absence (vehicle) or presence of sacubitril (1, 6, or 9 mg/kg per day), valsartan (0.3, 0.5, 1, 6, or 20 mg/kg per day), or the combination thereof (1 and 0.3, or 9 or 0.5 mg/kg per day of sacubitril and valsartan, respectively). Plasma AngII and renin concentrations increased 4-fold at higher valsartan doses, indicative of removal of AngII negative feedback on renin. Sacubitril doubled plasma AngII concentrations at lower doses (1 mg/kg per day). Valsartan dose-dependently decreased systolic blood pressure, aortic atherosclerosis, and AAAs of AngII-infused mice, whereas sacubitril had no effect on atherosclerosis or AAAs but reduced blood pressure of AngII-infused mice. Combination therapy with sacubitril and valsartan did not provide additive benefits. These results suggest limited effects of combination therapy with NEP inhibition and AT1R antagonism against AngII-induced hypertension, atherosclerosis, or AAAs. SIGNIFICANCE STATEMENT: The combination of valsartan (angiotensin type 1 receptor antagonist) and sacubitril (neprilysin inhibitor) did not provide benefit above valsartan alone on AngII-induced hypertension, atherosclerosis, or abdominal aortic aneurysms in low-density lipoprotein receptor-deficient male mice. These results do not support this drug combination in therapy of these AngII-induced cardiovascular diseases.

LCZ696 Attenuated Doxorubicin-Induced Chronic Cardiomyopathy Through the TLR2-MyD88 Complex Formation

Background and Purpose

The profibrotic and proinflammatory effects induced by doxorubicin (DOX) are key processes in the development of serious heart damage. Lack of effective drugs and the unclear mechanisms of its side effects limit the clinical treatment of DOX-induced cardiac injury. This study aimed to explore the protective role of LCZ696 and the potential mechanism of Toll-like receptor 2 (TLR2) in doxorubicin-induced cardiac failure.

Experimental Approach

DOX (5 mg/kg/week, three times) was used to establish a chronic cardiomyopathy mouse model. Heart function tests, pathology examinations and molecular biology analyses were used to explore the effects of LCZ696 and TLR2 deficiency in vivo and in vitro. Computational docking was applied to predict the key residues for protein-ligand interaction.

Key Results

The EF% declined, and the LVIDd, pro-fibrosis marker levels and NF-κB related inflammatory response increased in the chronic cardiomyopathy group induced by DOX. LCZ696 treatment and TLR2 deficiency reversed these heart damage in vivo. In H9C2 cells, pre-treatment with LCZ696 and TLR2 knockdown suppressed the DOX-induced high expression of profibrotic and proinflammatory markers. Moreover, DOX notably increased the TLR2-MyD88 interaction in vivo and in vitro, which was inhibited by LCZ696. Finally, we demonstrated the direct interaction between DOX and TLR2 via hydrogen bonds on Pro-681 and Glu-727 and Pro-681 and Ser-704 may be the key residues by which LCZ696 affects the interaction between DOX and TLR2.

Conclusion and Implications

LCZ696 prevents DOX-induced cardiac dilation failure, fibrosis and inflammation by reducing the formation of TLR2-MyD88 complexes. LZC696 may be a potential effective drug to treat DOX-induced heart failure.

Diabetic cardiomyopathy and inflammation: development of hostile microenvironment resulting in cardiac damage

Diabetes mellitus is emerging as a major risk factor for heart failure. Diabetic cardiomyopathy is defined as a myocardial dysfunction that is not caused by underlying hypertension or coronary artery disease. Studies about clinical features, natural history and outcomes of the disease are few and often conflicting, because a universally accepted operative definition of diabetic cardiomyopathy is still lacking. Hyperglycemia and related metabolic and endocrine disorders are the triggering factors of myocardial damage in diabetic cardiomyopathy through multiple mechanisms. Among these mechanisms, inflammation has a relevant role, similar to other chronic myocardial disease, such as hypertensive or ischemic heart disease. A balance between inflammatory damage and healing processes is fundamental for homeostasis of myocardial tissue, whereas diabetes mellitus produces an imbalance, promoting inflammation and delaying healing. Therefore, diabetes-related chronic inflammatory state can produce a progressive qualitative deterioration of myocardial tissue, which reflects on progressive left ventricular functional impairment, which can be either diastolic, with prevalent myocardial hypertrophy, or systolic, with prevalent myocardial fibrosis. The aim of this narrative review is to summarize the existing evidence about the role of inflammation in diabetic cardiomyopathy onset and development. Ultimately, potential pharmacological strategies targeting inflammatory response will be reviewed and discussed.