Ramipril and telmisartan exhibit differential effects in cardiac pressure overload-induced hypertrophy without an additional benefit of the combination of both drugs

Experimental model of congestive heart failure induced by transverse aortic constriction in BALB/c mice

INTRODUCTION

Murine transverse aortic constriction (TAC) is a frequently used model of pressure overload-induced left ventricular (LV) remodeling. However, there is considerable variability in disease progression to overt heart failure (HF) development in the most commonly used strain of mice (i.e., C57BL/6J). Studies have shown that C57BL/6J mice are more resistant than BALB/c mice to congestive HF development following myocardial infarction or angiotensin II-induced hypertension. Therefore, we tested the hypothesis that BALB/c mice may be a better research model to study TAC-induced progressive HF.

METHODS

Following sham or TAC surgery in both C57BL/6J (n = 29) and BALB/c (n = 32) mice, we evaluated cardiac dimensions and function by echocardiography at 2, 4, 8, and 12 weeks and monitored survival throughout the study. In a separate cohort of BALB/c mice, we repeated the study in the presence of the angiotensin converting enzyme inhibitor enalapril or a vehicle initiated 2 weeks post-TAC and administered for 6 weeks. At the end of the studies, we assessed the heart weight, lung weight, and plasma brain natriuretic peptide (BNP) concentration.

RESULTS

Following comparable TAC, both C57BL/6J and BALB/c mice showed significant LV remodeling compared with the sham control mice. BALB/c mice progressively developed systolic dysfunction, LV dilation, lung congestion, and significant mortality, whereas C57BL/6J mice did not. In the separate cohort of BALB/c TAC mice, enalapril significantly reduced the heart weight, lung weight, and plasma BNP concentration and improved survival compared with the vehicle control.

DISCUSSION

BALB/c mice uniformly developed congestive HF post-TAC. Enalapril was effective in improving survival and reducing lung congestion in this model. The data suggest that BALB/c mice may be a better research tool than C57BL/6J mice to study TAC-induced disease progression to HF and to evaluate novel therapies for the treatment of chronic HF with reduced ejection fraction.

The effect of RAS blockers on the clinical characteristics of COVID-19 patients with hypertension

Background

Coronavirus disease 2019 (COVID-19), caused by a novel coronavirus (designated as SARS-CoV-2) has become a pandemic worldwide. Based on the current reports, hypertension may be associated with increased risk of sever condition in hospitalized COVID-19 patients. Angiotensin-converting enzyme 2 (ACE2) was recently identified to functional receptor of SARS-CoV-2. Previous experimental data revealed ACE2 level was increased following treatment with ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). Currently doctors concern whether these commonly used renin-angiotensin system (RAS) blockers-ACEIs/ARBs may increase the severity of COVID-19.

Methods

We extracted data regarding 50 hospitalized hypertension patients with laboratory confirmed COVID-19 in the Renmin Hospital of Wuhan University from Feb 7 to Mar 03, 2020. These patients were grouped into RAS blockers group (Group A, n=20) and non-RAS blockers group (Group B, n=30) according to the basic blood pressure medications. All patients continued to use pre-admission antihypertensive drugs. Clinical severity (symptoms, laboratory and chest CT findings, etc.), clinical course, and short time outcome were analyzed after hospital admission.

Results

Ten (50%) and seventeen (56.7%) of the Group A and Group B participants were males (P=0.643), and the average age was 52.65±13.12 and 67.77±12.84 years (P=0.000), respectively. The blood pressure of both groups was under effective control. There was no significant difference in clinical severity, clinical course and in-hospital mortality between Group A and Group B. Serum cardiac troponin I (cTnI) (P=0.03), and N-terminal (NT)-pro hormone BNP (NT-proBNP) (P=0.04) showed significant lower level in Group A than in Group B. But the patients with more than 0.04ng/mL or elevated NT-proBNP level had no statistical significance between the two groups. In patients over 65 years or under 65 years, cTnI or NT-proBNP level showed no difference between the two groups.

Conclusions

We observed there was no obvious difference in clinical characteristics between RAS blockers and non-RAS blockers groups. These data suggest ACEIs/ARBs may have few effects on increasing the clinical severe conditions of COVID-19.

Liraglutide attenuates cardiac remodeling and improves heart function after abdominal aortic constriction through blocking angiotensin II type 1 receptor in rats

Objective

Angiotensin II (Ang II) is known to contribute to the pathogenesis of heart failure by eliciting cardiac remodeling and dysfunction. The glucagon-like peptide-1 (GLP-1) has been shown to exert cardioprotective effects in animals and patients. This study investigates whether GLP-1 receptor agonist liraglutide inhibits abdominal aortic constriction (AAC)-induced cardiac fibrosis and dysfunction through blocking Ang II type 1 receptor (AT1R) signaling.

Methods

Sprague-Dawley rats were subjected to sham operation and abdominal aortic banding procedure for 16 weeks. In treated rats, liraglutide (0.3 mg/kg) was subcutaneously injected twice daily or telmisartan (10 mg/kg/day), the AT1R blocker, was administered by gastric gavage.

Results

Relative to the animals with AAC, liraglutide reduced protein level of the AT1R and upregulated the AT2R, as evidenced by reduced ratio of AT1R/AT2R (0.59±0.04 vs. 0.91±0.06, p<0.05). Furthermore, the expression of angiotensin converting enzyme 2 was upregulated, tissue levels of malondialdehyde and B-type natriuretic peptide were reduced, and superoxide dismutase activity was increased. Along with a reduction in HW/BW ratio, cardiomyocyte hypertrophy was inhibited. In coincidence with these changes, liraglutide significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced protein levels of transforming growth factor beta1, Smad2/3/4, and upregulated smad7. The synthesis of collagen I and III was inhibited and collagen-rich fibrosis was attenuated. Consistent with these findings, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (110±5 vs. 99±2 mmHg, p<0.05), ejection fraction (83%±2% vs. 69%±4%, p<0.05) and fraction shortening (49%±2% vs. 35%±3%, p<0.05). Treatment with telmisartan provided a comparable level of protection as compared with liraglutide in all the parameters measured.

Conclusion

Taken together, liraglutide ameliorates cardiac fibrosis and dysfunction, potentially via suppressing the AT1R-mediated events. These data indicate that liraglutide might be selected as an add-on drug to prevent the progression of heart failure.

Stachydrine Ameliorates Cardiac Fibrosis Through Inhibition of Angiotensin II/Transformation Growth Factor β1 Fibrogenic Axis

Cardiovascular diseases, the leading cause of death worldwide, are tightly associated with the pathological myocardial fibrosis. Stachydrine (Sta), a major active compound in Chinese motherwort Leonurus heterophyllus, was reported to effectively attenuate cardiac fibrosis, but the cellular and molecular mechanism remains unclear. In this study, the anti-fibrotic effect of Sta and mechanism underlying were explored in a mouse model of pressure overload and AngII stimulated cardiac fibroblasts (CFs). Mice were randomly divided into sham, transverse aorta constriction with saline (TAC+Sal), TAC with telmisartan (TAC+Tel), and TAC with Sta (TAC+Sta) groups. Cardiac morphological and functional changes were evaluated by echocardiography and histological methods, and the molecular alterations were detected by western blotting. Primary cultured neonatal mouse CFs were treated with or without angiotensin II (AngII, 10⁻⁷ M), transformation growth factor β1 (TGFβ1, 10 ng/mL), and different dosage of Sta (10⁻⁶–10⁻⁴ M) for up to 96 h, and cell proliferation, cytotoxicity, morphology and related signals were also detected. The in vivo results revealed that TAC prominently induced cardiac dysfunction, left ventricular dilation, myocardial hypertrophy, and elevated myocardial collagen deposition, accompanied with increased fibrotic markers including α-smooth muscle actin (α-SMA) and periostin. However, Sta treatment partially reversed cardiac morphological and functional deteriorations, and significantly blunted cardiac fibrosis as well as Tel. Increments of myocardial angiotensinogen (AGT), angiotensin converting enzyme (ACE), AngII type 1 receptor (AT1R), and TGFβ1 transcripts, together with increased protein levels of ACE and AngII, after TAC were dramatically down-regulated by Sta treatment. Coincidently, in vitro experiments demonstrated that AngII stimulation in CFs led to up-regulation of AT1R and TGFβ1, and therefore promoted CFs trans-differentiating into hyper-activated myocardial fibroblasts (MFs) as evidenced by increased cell proliferation, collagen and fibrotic makers. On the contrary, Sta potently down-regulated but not directly inhibited AT1R, suppressed TGFβ1 production, and the pro-fibrotic effect of AngII in CFs. Moreover, activation of TGFβ1/Smads signal in the fibrotic process were observed both TAC model and in AngII stimulated CFs, which were also notably blunted by Sta. However, Sta failed to abolish the activation of CFs triggered by TGFβ1. Taken together, it was demonstrated in this study that Sta suppressed ACE/AngII/AT1R-TGFβ1 profibrotic axis, especially on the de novo production of AngII via down-regulating AGT/ACE and AT1R, and therefore inactivated CFs and blunted MFs transition, which ultimately prevented cardiac fibrosis.

The Effects of Guizhi Gancao Decoction on Pressure Overload-Induced Heart Failure and Posttranslational Modifications of Tubulin in Mice

Guizhi Gancao Decoction (GGD), a traditional Chinese medical recipe, has been widely used in the treatment of cardiovascular diseases in China for centuries. The present study was carried out to determine whether GGD exerts direct protective effects against pressure overload-induced heart failure. Moreover, we investigated whether GGD affects tubulin expression and posttranslational modifications. We demonstrated that GGD ameliorated TAC caused cardiac hypertrophy by gravimetric and echocardiography analysis in C57BL/6 mice. We found that GGD abrogated TAC-induced myocardium fibrosis by Masson's staining and collagen volume fraction (CVF) analysis. By using pressure-volume hemodynamic measurements, we found that GGD prevented TAC-induced cardiac systolic and diastolic dysfunction. Immunoblotting and immunofluorescent analysis revealed that GGD abrogated TAC-induced detyrosination and acetylation abnormalities on microtubules. Our present study demonstrated potential therapeutic effects of GGD against pressure overload-induced heart failure.

Telmisartan improves vascular remodeling through ameliorating prooxidant and profibrotic mechanisms in hypertension via the involvement of transforming growth factor-β1

Vascular remodeling is a common complication and pathological basis of hypertension. Transforming growth factor‑β1 (TGF‑β1)/small mothers against decapentaplegic 3 (Smad3) is considered a potential therapeutic target for vascular remodeling in hypertension. The present study aimed to demonstrate the antifibrotic effects of telmisartan and examined the potential mechanisms associated with its prevention of vascular remodeling. Spontaneously hypertensive rats (SHRs) were treated with telmisartan (20 mg/kg), and vascular contractility, reactivity and oxidative stress were preliminarily evaluated. Vascular pathological alterations and collagen deposition were assessed using hematoxylin and eosin, and Masson staining, respectively. The profibrotic factors, TGF‑β1 and Smad3 were evaluated using immunofluorescence and immunohistochemistry. The protein levels of TGF‑β1/Smad3, phosphorylated (p‑)Smad3, collagen‑1 and α-smooth muscle actin in the aorta were assessed using western blot analysis. It was found that telmisartan attenuated chronic vasoconstriction and oxidative stress in the SHRs, and improved vascular reactivity. Telmisartan also restored vascular pathological alterations and decreased collagen deposition. In the vascular wall of the SHRs, telmisartan effectively decreased the protein levels of TGF‑β1/Smad3 and p‑Smad3. Taken together, these findings indicated that telmisartan, with its antioxidant effect, prevented vascular remodeling in hypertension through preventing the TGF‑β1/Smad3 signaling pathway.

Effects of carvedilol on structural and functional outcomes and plasma biomarkers in the mouse transverse aortic constriction heart failure model

INTRODUCTION

Despite the widespread use of the mouse transverse aortic constriction heart failure model, there are no reports on the characterization of the standard-of-care agent carvedilol in this model.

METHODS

Left ventricular pressure overload was produced in mice by transverse aortic constriction between the innominate and left common carotid arteries. Carvedilol was administered at multiple dose levels (3, 10 and 30 mg/kg/day per os; yielding end-study mean plasma concentrations of 0.002, 0.015 and 0.044 µM, respectively) in a therapeutic design protocol with treatment initiated after the manifestation of left ventricular remodeling at 3 weeks post transverse aortic constriction and continued for 10 weeks.

RESULTS

Carvedilol treatment in transverse aortic constriction mice significantly decreased heart rate and left ventricular dP/dt (max) at all dose levels consistent with β-adrenoceptor blockade. The middle dose of carvedilol significantly decreased left ventricular weight, whereas the higher dose decreased total heart, left and right ventricular weight and wet lung weight compared to untreated transverse aortic constriction mice. The higher dose of carvedilol significantly increased cardiac performance as measured by ejection fraction and fractional shortening and decreased left ventricular end systolic volume consistent with the beneficial effect on cardiac function. End-study plasma sST-2 and Gal-3 levels did not differ among sham, transverse aortic constriction control and transverse aortic constriction carvedilol groups. Plasma brain natriuretic peptide concentrations were elevated significantly in transverse aortic constriction control animals (~150%) compared to shams in association with changes in ejection fraction and heart weight and tended to decrease (~30%, p = 0.10-0.12) with the mid- and high-dose carvedilol treatment.

CONCLUSION

A comparison of carvedilol hemodynamic and structural effects in the mouse transverse aortic constriction model versus clinical use indicates a strong agreement in effect profiles preclinical versus clinical, providing important translational validation for this widely used animal model. The present plasma brain natriuretic peptide biomarker findings support the measurement of plasma natriuretic peptides in the mouse transverse aortic constriction model to extend the translational utility of the model.

Telmisartan suppresses cardiac hypertrophy by inhibiting cardiomyocyte apoptosis via the NFAT/ANP/BNP signaling pathway

Telmisartan, a type of angiotensin II (Ang II) receptor inhibitor, is a common agent used to treat hypertension in the clinic. Hypertension increases cardiac afterload and promotes cardiac hypertrophy. However, the ventricular Ang II receptor may be activated in the absence of hypertension. Therefore, telmisartan may reduce cardiac hypertrophy by indirectly ameliorating hypertensive symptoms and directly inhibiting the cardiac Ang II receptor. Nuclear factor of activated T-cells (NFAT) contributes to cardiac hypertrophy via nuclear translocation, which induces a cascade of atrial natriuretic peptide (ANP) and brain/B-type natriuretic peptide (BNP) expression and cardiomyocyte apoptosis. However, NFAT-mediated inhibition of cardiac hypertrophy by telmisartan remains poorly understood. The present study demonstrated that telmisartan suppressed cardiomyocyte hypertrophy in a mouse model of cardiac afterload and in cultured cardiomyocytes by inhibiting NFAT nuclear translocation, as well as by inhibiting ANP and BNP expression and cardiomyocyte apoptosis, in a dose-dependent manner. The present study provides a novel insight into the potential underlying mechanisms of telmisartan-induced inhibition of cardiomyocyte hypertrophy, which involves inhibition of NFAT activation, nuclear translocation and the ANP/BNP cascade.

Combined statin and angiotensin-converting enzyme (ACE) inhibitor treatment increases the lifespan of long-lived F1 male mice

Statins, such as simvastatin, and ACE inhibitors (ACEis), such as ramipril, are standard therapies for the prevention and treatment of cardiovascular diseases. These types of drugs are commonly administered together. More recently, angiotensin II type 1 receptor (AT1R) antagonists, such as candesartan cilexetil (candesartan), have been used in the place of, or in combination with, ACEis. Here, we investigated the effects of simvastatin and ramipril single and combination therapy, and candesartan treatment on the lifespan of isocalorically fed, long-lived, B6C3F1 mice. Males were used for their relative endocrine simplicity and to minimize animal usage. The drugs were administered daily in food. The simvastatin and ramipril combination therapy significantly increased the mean and median lifespan by 9 %. In contrast, simvastatin, ramipril, or candesartan monotherapy was ineffective. All groups consumed the same number of calories. Simvastatin, alone or administered with ramipril, decreased body weight without changing caloric consumption, suggesting it may alter energy utilization in mice. Combination therapy elevated serum triglyceride and glucose levels, consistent with altered energy homeostasis. Few significant or consistent differences were found in mortality-associated pathologies among the groups. Simvastatin treatment did not reduce normal serum cholesterol or lipid levels in these mice, suggesting that the longevity effects may stem from the pleiotropic, non-cholesterol-related, effects of statins. Together, the results suggest that statins and ACEis together may enhance mouse longevity. Statins and ACE inhibitors are generally well-tolerated, and in combination, they have been shown to increase the lifespan of normotensive, normocholesterolemic humans.

Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease

We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.

Pathological Left Ventricular Hypertrophy and Stem Cells: Current Evidence and New Perspectives

Left ventricular hypertrophy (LVH) is a strong predictor of adverse cardiovascular outcomes. It is the result of complex mechanisms that include not only an increase in protein synthesis and cell size but also proliferating cardiac progenitor cells and the influx of bone marrow-derived cells developing into cardiomyocytes. Stem and progenitor cells are known to contribute to the renewal of adult mammalian cardiomyocytes in case of myocardial injury or pressure and volume overload. They are activated in LVH and play a regulatory role in myocardial repair. They have high proliferative potential and secrete numerous cytokines, growth factors, and microRNAs that play important roles in cell differentiation, cardiac remodeling, and neovascularization. They are mobilized in response to either mechanical or chemical stimuli, hormones, or pharmacologic agents. Another important source of progenitor cells is the epicardial layer. It appears that precursor cells migrate from the epicardium to the myocardium in order to interact with myocardial cells. In addition, migratory cells participate in the formation of almost all cardiac structures in myocardial hypertrophy. Although the pathophysiological mechanisms are still obscure and further studies are required, their properties may open the door to regenerative cell therapy for the prevention of adverse remodeling.

Effects of telmisartan and linagliptin when used in combination on blood pressure and oxidative stress in rats with 2-kidney-1-clip hypertension

OBJECTIVE

To investigate the effects of linagliptin alone and in combination with the angiotensin II receptor blocker (ARB), telmisartan on blood pressure (BP), kidney function, heart morphology and oxidative stress in rats with renovascular hypertension.

METHODS

Fifty-seven male Wistar rats underwent unilateral surgical stenosis of the renal artery [2-kidney-1-clip (2k1c) method]. Animals were randomly divided into four treatment groups (n = 14-18 per group) receiving: telmisartan (10 mg/kg per day in drinking water), linagliptin (89 ppm in chow), combination (linagliptin 89 ppm + telmisartan 10 mg/kg per day) or placebo. An additional group of 12 rats underwent sham surgery. BP was measured one week after surgery. Hypertensive animals entered a 16-week dosing period. BP was measured 2, 4, 8, 12 and 16 weeks after the initiation of treatment. Blood and urine were tested for assessment of kidney function and oxidative stress 6, 10, 14 and 18 weeks after surgery. Blood and urine sampling and organ harvesting were finally performed.

RESULTS

Renal stenosis caused an increase in mean ± SD systolic BP as compared with the sham group (157.7 ± 29.3 vs. 106.2 ± 20.5 mmHg, respectively; P < 0.001). Telmisartan alone and in combination with linagliptin, normalized SBP (111.1 ± 24.3 mmHg and 100.4 ± 13.9 mmHg, respectively; P < 0.001 vs. placebo). Telmisartan alone and in combination with linagliptin significantly prevented cardiac hypertrophy, measured by heart weight and myocyte diameter. Renal function measured by cystatin C was not affected by 2k1c surgery. Telmisartan significantly increased plasma concentration of cystatin C. 2k1c surgery initiated fibrosis in both kidneys. Telmisartan promoted further fibrotic changes in the clipped kidney, as measured by protein expression of Col1a1 and histology for interstitial fibrosis and glomerulosclerosis. In non-clipped kidneys, telmisartan demonstrated antifibrotic properties, reducing Col1a1 protein expression. Plasma levels of oxidized low-density lipoprotein were higher in the placebo-treated 2k1c rats as compared to sham-operated animals. The increase was abolished by linagliptin alone (P = 0.03 vs. placebo) and in combination with telmisartan (P = 0.02 vs. placebo). Combination therapy also significantly reduced plasma concentration of carbonyl proteins (P = 0.04 vs. placebo).

CONCLUSION

Inhibition of type 4 dipeptidyl peptidase with linagliptin did not counter BP-lowering effects of ARB in 2k1c rats. Linagliptin reduced lipid and protein oxidation in 2k1c rats, and this effect was BP-independent.

Mean platelet volume and left ventricular geometry in patients with aortic valve stenosis

BACKGROUND

Mean platelet volume (MPV) is a well-established marker of platelet activation. In the current study, we compared MPV between patients with aortic valve stenosis (AS) and control subjects. We also assessed the association between MPV and left ventricular geometry in patients with AS.

METHODS AND RESULTS

The study population consisted of 75 patients with AS and 38 age- and sex-matched control subjects. In patients with AS, peak pressure gradient was 83.0 ± 30.8 mm Hg. MPV was significantly larger in patients with AS than control subjects (10.57 ± 1.05 fl versus 9.72 ± 0.66 fl, p < 0.001). There was a significant association between peak pressure gradient and MPV in 75 patients with AS and 38 control subjects (r = 0.35, p < 0.001). Among the patients with AS, there were 12 patients with normal geometry, 10 patients with concentric remodeling, 14 patients with eccentric hypertrophy and 39 patients with concentric hypertrophy. There was no significant difference in MPV among the four groups. There was no significant association between MPV and LVM index.

CONCLUSIONS

Our data suggested that MPV increased in patients with AS, but did not reflect left ventricular geometry.

The efficacy and tolerability of azilsartan in obese insulin-resistant mice with left ventricular pressure overload

Angiotensin II receptor blockers (ARBs) are used widely for the treatment of heart failure. However, their use in obese and insulin-resistant patients remains controversial. To clarify their potential efficacy in these conditions, we administered azilsartan medoxomil (azilsartan), a prodrug of an angiotensin II receptor blocker to mice fed a high-fat diet (HFD) with left ventricular (LV) pressure overload (aortic banding). LV fibrosis (hydroxyproline), cardiac plasminogen activator inhibitor-1 (PAI-1; a marker of profibrosis), and creatine kinase (a marker of myocardial viability and energetics) were assessed. LV wall thickness and cardiac function were assessed echocardiographically. Mice given a HFD were obese and insulin resistant. Their LV hypertrophy was accompanied by greater LV PAI-1 and reduced LV creatine kinase compared with normal diet controls. Drug treatment reduced LV wall thickness, hypertrophy, and PAI-1 and increased cardiac output after aortic banding compared with results in HFD vehicle controls. Thus, azilsartan exerted favorable biological effects on the hearts of obese insulin-resistant mice subjected to LV pressure overload consistent with its potential utility in patients with analogous conditions.