Eicosapentaenoic acid ameliorates pulmonary hypertension via inhibition of tyrosine kinase Fyn.

Pulmonary arterial hypertension (PAH) is a multifactorial disease characterized by pulmonary arterial vasoconstriction and remodeling. Src family tyrosine kinases, including Fyn, play critical roles in vascular remodeling via the inhibition of STAT3 signaling. EPA is known to inhibit Fyn kinase activity. This study investigated the therapeutic potential and underlying mechanisms of EPA and its metabolite, resolvin E1 (RvE1), to treat PAH using monocrotaline-induced PAH model rats (MCT-PAH), human pulmonary artery endothelial cells (HPAECs), and human pulmonary artery smooth muscle cells (HPASMCs). Administration of EPA 1 and 2 weeks after MCT injection both ameliorated right ventricular hypertrophy, remodeling and dysfunction, and medial wall thickening of the pulmonary arteries and prolonged survival in MCT-PAH rats. EPA attenuated the enhanced contractile response to 5-hydroxytryptamine in isolated pulmonary arteries of MCT-PAH rats. Mechanistically, the treatment with EPA and RvE1 or the introduction of dominant-negative Fyn prevented TGF-ß2-induced endothelial-to-mesenchymal transition and IL-6-induced phosphorylation of STAT3 in cultured HPAECs. EPA and RvE1 suppressed Src family kinases' activity as evaluated by their phosphorylation status in cultured HPAECs and HPASMCs. EPA and RvE1 suppressed vasocontraction of rat and human PA. Furthermore, EPA and RvE1 inhibited the enhanced proliferation and activity of Src family kinases in HPASMCs derived from patients with idiopathic PAH. EPA ameliorated PAH's pathophysiology by mitigating vascular remodeling and vasoconstriction, probably inhibiting Src family kinases, especially Fyn. Thus, EPA is considered a potent therapeutic agent for the treatment of PAH.

Correction to: Randomized trial of an increased dose of calcium channel blocker or angiotensin II type 1 receptor blocker as an add-on intensive depressor therapy in type 2 diabetes mellitus patients with uncontrolled essential hypertension: the ACADEMIE Study.

In the Original publication of the article, the legend appearing inside the flow chart has been incorrectly published.

Randomized trial of an increased dose of calcium channel blocker or angiotensin II type 1 receptor blocker as an add-on intensive depressor therapy in type 2 diabetes mellitus patients with uncontrolled essential hypertension: the ACADEMIE Study.

There is a lack of data on how to treat hypertensive patients with diabetes when treatment with medium doses of calcium channel blocker and angiotensin II type 1 receptor blocker (ARB) is insufficient to achieve the target blood pressure (BP). A total of 121 participants with type 2 diabetes and uncontrolled essential hypertension, who were receiving medium doses of amlodipine (5 mg/day) and ARB, were enrolled. Participants were randomized to receive either a high dose of amlodipine (10 mg/day) plus a medium dose of ARB (high-AML) or a medium dose of amlodipine (5 mg/day) plus a high dose of ARB (high-ARB). The depressor effects of these two regimens were monitored using a telemonitoring home BP-measuring system. Fifty-four patients were excluded after an observation period, and the remaining 67 eligible participants were randomized into the two groups; 42 which had a record of their home BP for analysis. The change in morning home systolic and diastolic BP was greater in the high-AML than in the high-ARB (systolic BP; - 7.9 mmHg vs. + 2.7 mmHg; p = 0.0002, diastolic BP; - 3.9 mmHg vs. + 0.6 mmHg; p = 0.0007). In addition, the home systolic and diastolic BP before going to bed and office systolic BP were significantly reduced from week 0 only in the high-AML. An increased dose of amlodipine, but not ARB, reduced home morning BP in hypertensive patients with type 2 diabetes who were already receiving combination therapy with medium doses of amlodipine and ARB.

Effects of Tolvaptan With or Without the Pre-Administration of Renin-Angiotensin System Blockers in Hospitalized Patients With Acute Decompensated Heart Failure.

We examined whether tolvaptan combined with an angiotensin II receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACE-I) is more effective than tolvaptan alone in the treatment of patients with heart failure (HF). Sixty-five hospitalized patients with acute decompensated HF were included in this study. They were divided into 2 groups; an ARB/ACE-I group (n = 44, who received ARB or ACE-I before the use of tolvaptan) and a non-ARB/ACE-I group (n = 21). There were no significant differences in patient characteristics including medications at baseline between the non-ARB/ACE-I and ARB/ACE-I groups with the exception of the percentages of hypertension and ischemic heart disease. Urinary volume (UV) at baseline in the ARB/ACE-I group was slightly higher than that in the non-ARB/ACE-I group. The increase in UV after the use of tolvaptan in the non-ARB/ACE-I group was significantly higher than that in the ARB/ACE-I group. The cardiothoracic ratio and the reduction in body weight were similar between the groups after tolvaptan use. Finally, in a logistic regression analysis, a response to the use of tolvaptan was independently associated with the non-use of ARB/ACE-I, but not with age, gender, body mass index, loop diuretic, or human arterial natriuretic peptide. In conclusion, tolvaptan alone might induce an increase in UV in decompensated HF patients without ARB/ ACE-I, although the treatment of HF with ARB/ACE-I is the first choice strategy.

Depressor effect of chymase inhibitor in mice with high salt-induced moderate hypertension.

The aim of the present study was to determine whether long-term high salt intake in the drinking water induces hypertension in wild-type (WT) mice and whether a chymase inhibitor or other antihypertensive drugs could reverse the increase of blood pressure. Eight-week-old male WT mice were supplied with drinking water containing 2% salt for 12 wk (high-salt group) or high-salt drinking water plus an oral chymase inhibitor (TPC-806) at four different doses (25, 50, 75, or 100 mg/kg), captopril (75 mg/kg), losartan (100 mg/kg), hydrochlorothiazide (3 mg/kg), eplerenone (200 mg/kg), or amlodipine (6 mg/kg). Control groups were given normal water with or without the chymase inhibitor. Blood pressure and heart rate gradually showed a significant increase in the high-salt group, whereas a dose-dependent depressor effect of the chymase inhibitor was observed. There was also partial improvement of hypertension in the losartan- and eplerenone-treated groups but not in the captopril-, hydrochlorothiazide-, and amlodipine-treated groups. A high salt load significantly increased chymase-dependent ANG II-forming activity in the alimentary tract. In addition, the relative contribution of chymase to ANG II formation, but not actual average activity, showed a significant increase in skin and skeletal muscle, whereas angiotensin-converting enzyme-dependent ANG II-forming activity and its relative contribution were reduced by high salt intake. Plasma and urinary renin-angiotensin system components were significantly increased in the high-salt group but were significantly suppressed in the chymase inhibitor-treated group. In conclusion, 2% salt water drinking for 12 wk caused moderate hypertension and activated the renin-angiotensin system in WT mice. A chymase inhibitor suppressed both the elevation of blood pressure and heart rate, indicating a definite involvement of chymase in salt-sensitive hypertension.

Addition of a Nitric Oxide Donor to an Angiotensin II Type 1 Receptor Blocker May Cancel Its Blood Pressure-Lowering Effects.

While physiological levels of nitric oxide (NO) protect the endothelium and have vasodilatory effects, excessive NO has adverse effects on the cardiovascular system. Recently, new NO-releasing pharmacodynamic hybrids of angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) have been developed.We analyzed whether olmesartan with NO-donor side chains (Olm-NO) was superior to olmesartan (Olm) for the control of blood pressure (BP). Although there was no significant difference in binding affinity to AT1 wild-type (WT) receptor between Olm and Olm-NO in a cell-based binding assay, the suppressive effect of Olm-NO on Ang II-induced inositol phosphate (IP) production was significantly weaker than that of Olm in AT1 WT receptor-expressing cells. While Olm had a strong inverse agonistic effect on IP production, Olm-NO did not. Next, we divided 18 C57BL mice into 3 groups: Ang II (infusion using an osmotic mini-pump) as a control group, Ang II (n = 6) + Olm, and Ang II (n = 6) + Olm-NO groups (n = 6). Olm-NO did not block Ang II-induced high BP after 10 days, whereas Olm significantly decreased BP. In addition, Olm, but not Olm-NO, significantly reduced the ratio of heart weight to body weight (HW/BW) with downregulation of the mRNA levels of atrial natriuretic peptide.An ARB with a NO-donor may cancel BP-lowering effects probably due to excessive NO and a weak blocking effect by Olm-NO toward AT1 receptor activation.

Impact of cigarette smoking cessation on high-density lipoprotein functionality.

BACKGROUND: Smoking cessation reduces the risk of cardiovascular disease (CVD) and improves clinical outcomes in public health. We studied the effect of smoking cessation on high-density lipoprotein (HDL) functionality. METHODS AND RESULTS: We randomly treated 32 smokers with varenicline or a transdermal nicotine patch as part of a 12-week smoking cessation program (The VN-SEESAW Study). The plasma lipid profiles, plasma and HDL malondialdehyde (MDA) levels, HDL subfractions as analyzed by capillary isotachophoresis, cholesterol efflux capacity, and antiinflammatory activity of HDL were measured before and after the anti-smoking intervention. After smoking cessation, HDL-C, apoA-I levels and HDL subfractions were not significantly different from the respective baseline values. However, cholesterol efflux capacity and the HDL inflammatory index (HII) were significantly improved after smoking cessation. The changes in both parameters (%∆ cholesterol efflux capacity and ∆HII) were also significantly improved in the successful smoking cessation group compared with the unsuccessful group. The changes in cholesterol efflux capacity and HII also correlated with those in end-expiratory CO concentration and MDA in HDL, respectively. CONCLUSIONS: Our findings indicate that smoking cessation leads to improved HDL functionality, increased cholesterol efflux capacity and decreased HII, without changing HDL-C or apoA-I levels or HDL subfractions. This may be one of the mechanisms by which smoking cessation improves the risk of CVD.

Novel molecular imaging of atherosclerosis with gallium-68-labeled apolipoprotein A-I mimetic peptide and positron emission tomography.

BACKGROUND: High-density lipoprotein (HDL) plays a major role in reverse cholesterol transport. Many researchers have been working to enhance the biochemical function of HDL for use in therapy. Although HDL therapy using injections of apolipoprotein (apo)-A-I mimetics, apo A-I Milano or full-length apo A-I is dramatically effective, it is still unclear whether apo A-I or apo A-I mimetics actually enter atherosclerotic plaque and remove cholesterol from the lipid burden. We synthesized a novel 24-amino acid apo A-I mimetic peptide (known as FAMP) that potently removes cholesterol via specific ATP-binding cassette transporter A1. We then investigated the potential of FAMP to image developing plaque lesions in vivo. METHODS AND RESULTS: FAMP was modified with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and radiolabeled with gallium-68 ((68)Ga) for noninvasive positron emission tomography (PET) in an animal model (familial hypercholesterolemic myocardial infarction-prone rabbits: WHHL-MI) with atherosclerotic lesions. The (68)Ga-DOTA-FAMP was dramatically taken up by atherosclerotic tissues in the blood vessels and aorta of WHHL-MI rabbits, but not the control rabbits. CONCLUSIONS: An apo A-I mimetic peptide with (68)Ga-DOTA is a promising candidate diagnostic tracer for PET imaging of the atherosclerotic lipid burden and may contribute to the development of a tool for the diagnosis of plaque with PET.

Lifestyle changes through the use of delivered meals and dietary counseling in a single-blind study. The STYLIST study.

BACKGROUND: Dietary habits are associated with obesity, and both are important contributing factors to lifestyle-related diseases. The STYLIST study examined the effects of dietary counseling by registered dietitians and the delivery of proper calorie-controlled meals (UMIN Registration No: 000006582). METHODS AND RESULTS: Two-hundred adult patients with hypertension and/or diabetes mellitus were randomly divided into 2 groups with/without dietary counseling and consumed an ordinary diet for 4 weeks. Each group was then subdivided into 2 groups with/without dietary counseling and received calorie-controlled lunch and dinner boxes for the next 4 weeks. The calories in the delivered meals were based on the subject's ideal body weight (BW) and physical activity level. BW, waist circumference, blood pressure, and laboratory data, including glycoalbumin, were measured at 0, 4, and 8 weeks. BW and the other parameters were significantly reduced during the study period in patients who received diet counseling in the ordinary diet period and/or delivered meal period but not in patients without dietary counseling, as assessed by linear mixed models for longitudinal data. CONCLUSIONS: The combination of dietary counseling by dietitians and delivery of calorie-controlled meals was effective in reducing BW, as well as blood pressure and glycoalbumin, in patients with hypertension and/or diabetes mellitus.

Substantial involvement of TRPM7 inhibition in the therapeutic effect of Ophiocordyceps sinensis on pulmonary hypertension.

Ophiocordyceps sinensis (OCS), an entomopathogenic fungus, is known to exert antiproliferative and antitissue remodeling effects. Vascular remodeling and vasoconstriction play critical roles in the development of pulmonary hypertension (PH). The therapeutic potential of OCS for PH was investigated using rodent PH models, and cultured pulmonary artery endothelial and smooth muscle cells (PAECs and PASMCs), with a focus on the involvement of TRPM7. OCS ameliorated the development of PH, right ventricular hypertrophy and dysfunction in the monocrotaline-induced PH rats. The genetic knockout of TRPM7 attenuated the development of PH in mice with monocrotaline pyrrole-induced PH. TRPM7 was associated with medial hypertrophy and the plexiform lesions in rats and humans with PH. OCS suppressed proliferation of PASMCs derived from the PH patients. Ethanol extracts of OCS inhibited TRPM7-like current, TGF-ß2-induced endothelial-mesenchymal transition, IL-6-induced STAT3 phosphorylation, and PDGF-induced Akt phosphorylation in PAECs or PASMCs. These inhibitory effects were recapitulated by either siRNA-mediated TRPM7 knockdown or treatment with TRPM7 antagonist FTY-720. OCS and FTY-720 induced vasorelaxation in the isolated normal human pulmonary artery. As a result, the present study proposes the therapeutic potential of OCS for the treatment of PH. The inhibition of TRPM7 is suggested to underlie the therapeutic effect of OCS.

c-kit is required for cardiomyocyte terminal differentiation.

c-kit, the transmembrane tyrosine kinase receptor for stem cell factor, is required for melanocyte and mast cell development, hematopoiesis, and differentiation of spermatogonial stem cells. We show here that in the heart, c-kit is expressed not only by cardiac stem cells but also by cardiomyocytes, commencing immediately after birth and terminating a few days later, coincident with the onset of cardiomyocyte terminal differentiation. To examine the function of c-kit in cardiomyocyte terminal differentiation, we used compound heterozygous mice carrying the W (null) and W(v) (dominant negative) mutations of c-kit. In vivo, adult W/W(v) cardiomyocytes are phenotypically indistinguishable from their wild-type counterparts. After acute pressure overload adult W/W(v) cardiomyocytes reenter the cell cycle and proliferate, leading to left ventricular growth; furthermore in transgenic mice with cardiomyocyte-restricted overexpression of the dominant negative W(v) mutant, pressure overload causes cardiomyocytes to reenter the cell cycle. In contrast, in wild-type mice left ventricular growth after pressure overload results mainly from cardiomyocyte hypertrophy. Importantly, W/W(v) mice with pressure overload-induced cardiomyocyte hyperplasia had improved left ventricular function and survival. In W/W(v) mice, c-kit dysfunction also resulted in an approximately 14-fold decrease (P<0.01) in the number of c-kit(+)/GATA4(+) cardiac progenitors. These findings identify novel functions for c-kit: promotion of cardiac stem cell differentiation and regulation of cardiomyocyte terminal differentiation.

Insights into the characteristics of mammalian cardiomyocyte terminal differentiation shown through the study of mice with a dysfunctional c-kit.

Mammalian cardiomyocytes withdraw from the cell cycle soon after birth. This process is called terminal differentiation. The c-kit, a receptor tyrosine kinase, is expressed on cardiomyocytes immediately after birth but for only a few days. In mice with genetic c-kit dysfunction, adult cardiomyocytes are phenotypically indistinguishable from those of wild type mice, except that they are capable of proliferation in vivo after acute pressure overload. This review explores the idea that postnatal cardiomyocyte differentiation and cell cycle withdrawal are distinct processes and that terminal differentiation may not simply be due to altered expression of genes that regulate the cell cycle but could involve c-kit induced epigenetic change.

Depressor effect of the young leaves of Polygonum hydropiper Linn. in high-salt induced hypertensive mice.

A novel chymase inhibitor has been reported to have depressor effect in salt-induced hypertension. Therefore, we examined the hypothesis that chymase inhibitory dried young leaves of Polygonum hydropiper (PPH) or young leaves extract of Polygonum hydropiper (PHE) could reduce salt-induced hypertension. In this study, 8-wk old wild-type mice were allocated into three experiments and experiment I included groups, I- normal water drinking, II- high salt (2% NaCl) water (HSW) drinking, and III- HSW plus PPH (500 mg kg-1, orally) for 12-wk. Blood pressure (BP) and heart rate (HR) were measured at baseline and weekly up to wk-12. In experiment II, mice were given HSW for 12-wk followed by 8-wk treatment with PPH plus HSW (62.5, 125, 250 and 500 mg kg-1 for groups I, II, III and IV, respectively). BP and HR were measured at baseline and monthly until wk-12, following weekly for 8-wk. Experiment III comprised of four groups of mice for 12-wk HSW and 8-wk treatment with PHE plus HSW (2.5, 5, 10 and 20 mg kg-1 for groups I-IV, respectively). BP and HR were measured at baseline and monthly up to wk-12, following weekly for 8-wk. Significant reduction in BP and HR were observed in mice treated with PPH (500 mg kg-1) compared to HSW control. PPH reduced BP and HR dose dependently in hypertensive mice and the higher dose showed maximum reduction. PHE at its maximum dose (20 mg kg-1) significantly suppressed BP and HR. Over all, we found that the young leaves of Polygonum hydropiper suppressed salt-induced hypertension.

The Change in Body Weight During Hospitalization Predicts Mortality in Patients With Acute Decompensated Heart Failure.

BACKGROUND: In our experience, the change in body weight (BW) during hospitalization varies greatly in patients with acute decompensated heart failure (HF). Since the clinical significance of a change in BW is not clear, we investigated whether a change in BW could predict mortality. METHODS: We retrospectively enrolled 130 patients (72 males; aged 68 ± 10 years) who were hospitalized due to acute decompensated HF and followed for 2 years after discharge. The change in the BW index during hospitalization (ΔBWI) was calculated as (BW at hospital admission minus BW at hospital discharge)/body surface area at hospital discharge. RESULTS: The patients were divided into quartiles according to ΔBWI, and the 2-year mortality rates in the quartiles with the lowest, second, third and highest ΔBWI were 18.8%, 12.1%, 3.1% and 9.1%, respectively. In a multivariate Cox proportional hazards analysis after adjusting for variables with a P value less than 0.05, ΔBWI was independently associated with 2-year mortality (P = 0.0002), and the quartile with the lowest ΔBWI had a higher relative risk (RR) for 2-year mortality than the quartile with the highest ΔBWI (RR: 7.46, 95% confidence interval: 1.03 - 53.99, P = 0.04). CONCLUSION: In conclusion, ΔBWI was significantly associated with 2-year mortality after discharge, which indicates that ΔBWI might be a simple predictor of prognosis in acute decompensated HF.

Orally administered levofloxacin as prophylaxis against pacemaker infection.

OBJECTIVES: Despite paying careful attention to surgical details and sterile procedures, infection often occurs after pacemaker implantation. The prophylactic use of intravenously or orally administered antibiotics should therefore be considered. The present study aimed to evaluate the efficacy of orally administered levofloxacin (LVFX) as prophylaxis against pacemaker infection. METHODS: Thirty-nine patients who underwent permanent pacemaker implantation or pacemaker generator replacement due to battery depletion were included in the present study. Patients were divided into two groups (groups 1 and 2) and administered different antibiotics accordingly. Group 1 included 19 patients (75.7+/-9.3 years of age; 10 men and nine women) who were intravenously administered 2 g of cefazolin daily for five days postoperatively. Group 2 included 20 patients (73.7+/-14.4 years of age; 10 men and 10 women) who were orally administered 200 mg of LVFX 2 h before surgery and then 400 mg daily for five days thereafter. RESULTS: In group 1, the mean white blood cell concentrations before, and one, four and seven days after surgery were 4979+/-1330/mm(3), 6453+/-1200/mm(3), 5463+/-1303/mm(3) and 5632+/-1154/mm(3), respectively, and in group 2, they were 5931+/-1316/mm(3), 7062+/-1774/mm(3), 5708+/-1402/mm(3) and 5345+/-1506/mm(3), respectively. In group 1, the mean blood C-reactive protein concentrations before, and one, four and seven days after surgery were 0.27+/-0.34 mg/dL, 0.48+/-0.48 mg/dL, 1.04+/-0.99 mg/dL and 0.52+/-0.48 mg/dL, respectively, and in group 2, they were 0.43+/-0.54 mg/dL, 0.52+/-0.27 mg/dL, 0.61+/-0.42 mg/dL and 0.56+/-0.63 mg/dL, respectively. The inflammatory parameters showed similar responses in both groups. CONCLUSIONS: Orally administered LVFX following permanent pacemaker implantation can prevent pacemaker infection as successfully as intravenously administered cefazolin.

A novel inducible cholesterol efflux peptide, FAMP, protects against myocardial ischemia reperfusion injury through a nitric oxide pathway.

OBJECTIVE: We evaluated whether a novel inducible cholesterol efflux (iCE) peptide [Fukuoka University Apolipoprotein A-I Mimetic Peptide (FAMP)] protects against myocardial ischemia reperfusion injury (IRI) through a nitric oxide (NO) pathway by an improvement of high-density lipoprotein (HDL) functionality. METHODS AND RESULTS: Male C57BL6/J mice were intraperitoneally injected with phosphate buffer as a control, low-dose (10 mg/kg) or high-dose (50 mg/kg) of FAMP before 18 h of IRI (n=6-12 in each group). After 30 min of ischemia followed by 6h of reperfusion, blood pressure, and infarct size were measured and cardiac function was evaluated by a Millar catheter. FAMP significantly improved stroke volume, cardiac output, left ventricular ejection fraction, and infarct size. FAMP significantly preserved cytochrome C in the mitochondrial fraction and inhibited its release into the cytosolic fraction in the heart, but did not significantly reduce mRNA levels of monocyte chemoattractant protein-1 or interluekin-6. In a TdT-mediated dUTP nick end labeling (TUNEL) assay, FAMP significantly suppressed the appearance of TUNEL-positive nuclear. We also performed same experiments with endothelial nitric oxide synthase-knockout (eNOS-KO) mice and FAMP-induced improvements of cardiac function were not observed in eNOS-KO mice. CONCLUSIONS: FAMP activated HDL-functionality and improved cardiac function in a model of myocardial IRI. It may have anti-apoptotic effects by protecting mitochondria through a NO pathway as a pleiotropic effect.

Recent Patient Characteristics and Medications at Admission and Discharge in Hospitalized Patients With Heart Failure.

BACKGROUND: To improve the clinical outcome of heart failure (HF), it is important to evaluate the etiology and comorbidities of HF. We previously reported the baseline clinical characteristics and medications in hospitalized patients with HF in years 2000 - 2002 (group 2000) and 2007 - 2009 (group 2008). METHODS: We conducted a retrospective study of 158 patients who were hospitalized due to HF between 2012 and 2014 (group 2013) in the Department of Cardiology, Fukuoka University Hospital. We analyzed the clinical characteristics and medications at admission and discharge, and compared the findings in group 2013 to those in group 2000 and group 2008. RESULTS: The major causes of HF were ischemic heart disease, hypertensive cardiomyopathy, valvular heart disease, and dilated cardiomyopathy. The New York Heart Association classification in group 2013 was significantly higher than those in group 2000 and group 2008. There was no difference in the level of brain natriuretic peptide at admission between group 2008 and group 2013. Tolvaptan began to be administered in group 2013. The median dose of furosemide just before the use of tolvaptan was 40 mg/day. At discharge, group 2013 showed higher rates of ß-blocker and aldosterone antagonist. There was no difference in the frequency of loop diuretics. The dose of carvedilol at discharge was only 6.2 ± 4.0 mg/day. Antiarrhythmic drugs and ß-blocker were used more frequently in HF with reduced ejection fraction (EF) than in HF with preserved EF. CONCLUSIONS: We may be able to improve the clinical outcome of HF by examining the differences in the clinical characteristics and medications at admission and discharge in hospitalized patients with HF.

LCZ696, an angiotensin receptor-neprilysin inhibitor, improves cardiac function with the attenuation of fibrosis in heart failure with reduced ejection fraction in streptozotocin-induced diabetic mice.

AIMS: Angiotensin receptor-neprilysin inhibitors (ARNis) acts an ARB and neprilysin inhibitor. Diabetes mellitus significantly increases the risk of cardiovascular disease and heart failure (HF). Therefore, we evaluated the effects and mechanisms of ARNi in HF with reduced ejection fraction (HFrEF) in streptozotocin-induced diabetic mice. METHODS AND RESULTS: Male C57BL/6J mice were injected with streptozotocin to produce diabetic mice. After myocardial reperfusion injury, diabetic mice were randomized to treatment for 4 weeks with LCZ696 (60 mg/kg), valsartan (30 mg/kg), or no treatment (n = 26-28 in each group). Cardiac function was assessed by a pressure-volume Millar catheter. The ratios of heart weight to body weight in the valsartan (P = 0.02) and LCZ696 (P = 0.005) groups were significantly less than that in the control group. Treatment with LCZ696 improved LVEF (43 ± 3.4%) with a significantly reduction of atrial natriuretic peptide mRNA in the left ventricle compared with that in the control group (29 ± 3.2%) (P = 0.006). The fibrotic area in the LCZ696 group was significantly suppressed compared with those in the control (P = 0.003) and valsartan (P = 0.04) groups. Moreover, the mRNA level of transforming growth factor-ß (TGF-ß) in the left ventricle was suppressed in the LCZ696 group compared with that in the control (P = 0.002) group. CONCLUSION: The ARNi LCZ696 improved cardiac function with the reduction of fibrosis in an HF-rEF model in diabetic mice, by suppressing TGF-ß. This effect may be due to the specific inhibition of neprilysin, beyond the ARB effect of LCZ696.

The angiotensin II type 1 receptor-neprilysin inhibitor LCZ696 blocked aldosterone synthesis in a human adrenocortical cell line.

A recent clinical study indicated that an angiotensin II (Ang II) type 1 (AT1) receptor-neprilysin inhibitor (ARNi) designated LCZ696 (sacubitril/valsartan, as combined sodium complex) was superior to enalapril at reducing the risks of death and hospitalization due to heart failure. Therefore, we investigated the possible mechanisms of the beneficial effect of LCZ696, in which the inhibition of neprilysin enhances atrial natriuretic peptide (NP) or brain NP (ANP or BNP)-evoked signals that can block Ang II/AT1 receptor-induced aldosterone (Ald) synthesis in human adrenocortical cells. The binding affinity of valsartan+LBQ657 (active moiety of sacubitril) to the AT1 receptor was greater than that of valsartan alone in an AT1 receptor-expressing human embryonic kidney cell-based assay. There was no difference in the dissociation from the AT1 receptor between valsartan+LBQ657 and valsartan alone. In Ang II-sensitized human adrenocortical cells, ANP or BNP alone, but not LBQ657 or valsartan alone, significantly decreased Ald synthesis. The level of suppression of Ald synthesis by ANP or BNP with LBQ657 was greater than that by ANP or BNP without LBQ657. The suppression of ANP was blocked by inhibitors of regulator of G-protein signaling proteins and cyclic GMP-dependent protein kinase. The inhibition of neprilysin did not change the mRNA levels of the AT1 receptor, ANP receptor A, regulator of G-protein signaling protein, renin or 3ß-hydroxysteroid dehydrogenases. In conclusion, the inhibition of neprilysin by LBQ657 enhances the NP-evoked signals that can block Ang II/AT1 receptor-induced Ald synthesis in human adrenocortical cells.