Early administration of Enalapril prevents diastolic dysfunction and ventricular remodeling in rabbits with myocardial infarction

Safety, Feasibility, and Impact of Enalapril on Cardiorespiratory Physiology and Health in Preterm Infants with Systemic Hypertension and Left Ventricular Diastolic Dysfunction

Neonatal hypertension has been increasingly recognized in premature infants with bronchopulmonary dysplasia (BPD); of note, a sub-population of these infants may have impaired left ventricular (LV) diastolic function, warranting timely treatment to minimize long term repercussions. In this case series, enalapril, an angiotensin-converting enzyme (ACE) inhibitor, was started in neonates with systemic hypertension and echocardiography signs of LV diastolic dysfunction. A total of 11 patients were included with birth weight of 785 ± 239 grams and gestational age of 25.3 (24, 26.1) weeks. Blood pressure improvement was noticed within 2 weeks of treatment. Improvement in LV diastolic function indices were observed with a reduction in Isovolumic Relaxation Time (IVRT) from 63.1 ± 7.2 to 50.9 ± 7.4 msec and improvement in the left atrium size indexed to aorta (LA:Ao) from1.73 (1.43, 1.88) to 1.23 (1.07, 1.29). Neonatal systemic hypertension is often underappreciated in ex-preterm infants and may be associated with important maladaptive cardiac changes with long term implications. It is biologically plausible that identifying and treating LV diastolic dysfunction in neonates with systemic hypertension may have a positive modulator effect on cardiovascular health in childhood and beyond.

Early Preventive Treatment With Enalapril Improves Cardiac Function and Delays Mortality in Mice With Arrhythmogenic Right Ventricular Cardiomyopathy Type 5

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy type 5 (ARVC5) is an inherited cardiac disease with complete penetrance and an aggressive clinical course caused by mutations in TMEM43 (transmembrane protein 43). There is no cure for ARVC5 and palliative treatment is started once the phenotype is present. A transgenic mouse model of ARVC5 expressing human TMEM43-S358L (TMEM43mut) recapitulates the human disease, enabling the exploration of preventive treatments. The aim of this study is to determine whether preventive treatment with heart failure drugs (β-blockers, ACE [angiotensin-converting enzyme] inhibitors, mineralocorticoid-receptor antagonists) improves the disease course of ARVC5 in TMEM43mut mice.

METHODS

TMEM43mut male/female mice were treated with metoprolol (β-blockers), enalapril (ACE inhibitor), spironolactone (mineralocorticoid-receptor antagonist), ACE inhibitor + mineralocorticoid-receptor antagonist, ACE inhibitor + mineralocorticoid-receptor antagonist + β-blockers or left untreated. Drugs were initiated at 3 weeks of age, before ARVC5 phenotype, and serial ECG and echocardiograms were performed.

RESULTS

TMEM43mut mice treated with enalapril showed a significantly increased median survival compared with untreated mice (26 versus 21 weeks; P=0.003). Enalapril-treated mice also exhibited increased left ventricular ejection fraction at 4 months compared with controls (37.0% versus 24.9%; P=0.004), shorter QRS duration and reduced left ventricle fibrosis. Combined regimens including enalapril also showed positive effects. Metoprolol decreased QRS voltage prematurely and resulted in a nonsignificant decrease in left ventricular ejection fraction compared with untreated TMEM43mut mice.

CONCLUSIONS

Preventive enalapril-based regimens reduced fibrosis, improved ECG, echocardiographic parameters and survival of ARVC5 mice. Early metoprolol did not show positive effects and caused premature ECG abnormalities. Our findings pave the way to consider prophylactic enalapril in asymptomatic ARVC5 genetic carriers.

Nobiletin ameliorates cardiac impairment and alleviates cardiac remodeling after acute myocardial infarction in rats via JNK regulation

Nobiletin was found to protect against acute myocardial infarction (AMI)-induced cardiac function decline and myocardial remodeling, although the dose-effect relationship and underlying pathways remained unclear. In the current research, different doses of Nobiletin (7.5, 15 and 30 mg/kg/day) were administered to AMI rat model for 21 days. Survival rate, echocardiography, and histological analysis were assessed in vivo. In addition, MTT assay, flow cytometry, and Western blotting were conducted to explore Nobiletin's cytotoxicity and antiapoptotic effect on H9C2 cells. Mechanistically, the activation of MAPK effectors and p38 in vivo was studied. The results showed medium- and high-dose Nobiletin could significantly improve survival rate and cardiac function and reduce the area of infarction and cardiac fibrosis. Medium dose showed the best protection on cardiac functions, whereas high dose showed the best protective effect on cellular apoptosis and histological changes. JNK activation was significantly inhibited by Nobiletin in vivo, which could help to explain the partial contribution of autophagy to AMI-induced apoptosis and the discrepancy on dose-effect relationships. Together, our study suggested that JNK inhibition plays an important role in Nobiletin-induced antiapoptotic effect in myocardial infarction, and medium-dose Nobiletin demonstrated the strongest effect in vivo.

Nebivolol is more effective than atenolol for blood pressure variability attenuation and target organ damage prevention in L-NAME hypertensive rats

β-Adrenergic blockers are no longer recommended as first-line therapy due to the reduced cardioprotection of traditional β-blockers compared with other antihypertensive drugs. It is unknown whether third-generation β-blockers share the limitations of traditional β-blockers. The aim of the present study was to compare the effects of nebivolol or atenolol on central and peripheral systolic blood pressure (SBP) and its variability and target organ damage (TOD) in N-nitro-L-arginine methyl ester (L-NAME) hypertensive rats. Male Wistar rats were treated with L-NAME for 8 weeks together with oral administration of nebivolol 30 mg/kg (n = 8), atenolol 90 mg/kg (n = 8), or vehicle (n = 8). The control group was composed of vehicle-treated Wistar rats. SBP and its variability, as well as echocardiographic parameters, were assessed during the last 2 weeks of treatment. Tissue levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and transforming growth factor β (TGF-β), and histopathological parameters were evaluated in the left ventricle and aorta. Nebivolol had a greater ability than atenolol to decrease central SBP and mid-term and short-term blood pressure variability (BPV) in L-NAME rats. Echocardiographic analysis showed that nebivolol was more effective than atenolol on E/A wave ratio normalization. Compared with atenolol treatment, nebivolol had a greater protective effect on different TOD markers, inducing a decrease in collagen deposition and a reduction in the proinflammatory cytokines IL-6 and TNF-α in the left ventricle and aorta. Our findings suggest that the adverse hemodynamic profile and the reduced cardiovascular protection reported with traditional β-blockers must not be carried forward to third-generation β-blockers.

RAS inhibition in resident fibroblast biology

Angiotensin II (Ang II) is a primary mediator of profibrotic signaling in the heart and more specifically, the cardiac fibroblast. Ang II-mediated cardiomyocyte hypertrophy in combination with cardiac fibroblast proliferation, activation, and extracellular matrix production compromise cardiac function and increase mortality in humans. Profibrotic actions of Ang II are mediated by increasing production of fibrogenic mediators (e.g. transforming growth factor beta, scleraxis, osteopontin, and periostin), recruitment of immune cells, and via increased reactive oxygen species generation. Drugs that inhibit Ang II production or action, collectively referred to as renin angiotensin system (RAS) inhibitors, are first line therapeutics for heart failure. Moreover, transient RAS inhibition has been found to persistently alter hypertensive cardiac fibroblast responses to injury providing a useful tool to identify novel therapeutic targets. This review summarizes the profibrotic actions of Ang II and the known impact of RAS inhibition on cardiac fibroblast phenotype and cardiac remodeling.

Is the cardioprotective effect of the ACE2 activator diminazene aceturate more potent than the ACE inhibitor enalapril on acute myocardial infarction in rats?

Myocardial infarction is a major cause of cardiac dysfunction. All components of the cardiac renin-angiotensin system (RAS) are upregulated in myocardial infarction. Angiotensin-converting enzyme (ACE) and ACE2 are key enzymes involved in synthesis of components of RAS and provide a counter-regulatory mechanism within RAS. We compared the cardioprotective effect of the ACE2 activator diminazene aceturate (DIZE) versus the ACE inhibitor enalapril on post acute myocardial infarction (AMI) ventricular dysfunction in rats. Adult male rats received subcutaneous injections of either saline (control) or isoproterenol (85 mg/kg) to induce AMI. Rats with AMI confirmed biochemically and by ECG, were either left untreated (AMI) or administered DIZE (AMI + DIZE) or enalapril (AMI + enalapril) daily for 4 weeks. DIZE caused a significant activation of cardiac ACE2 compared with enalapril. DIZE caused a significantly greater enhancement of cardiac hemodynamics. DIZE also caused greater reductions in heart-type fatty acid binding protein (H-FABP), β-myosin heavy chain (β-MYH), and in heart mass to total body mass ratio. These results indicated that activation of cardiac ACE2 by DIZE enhanced the protective axis of RAS and improved myocardial function following AMI, whereas enalapril was not sufficient to restore all cardiac parameters back to normal.

LncRNA SLC8A1-AS1 protects against myocardial damage through activation of cGMP-PKG signaling pathway by inhibiting SLC8A1 in mice models of myocardial infarction

Extensive investigations into long noncoding RNAs (lncRNAs) in various diseases and cancers, including acute myocardial infarction (AMI) have been conducted. The current study aimed to investigate the role of lncRNA solute carrier family 8 member A1 antisense RNA 1 (SLC8A1-AS1) in myocardial damage by targeting solute carrier family 8 member A1 (SLC8A1) via cyclic guanosine 3',5'-monophosphate-protein kinase G (cGMP-PKG) signaling pathway in AMI mouse models. Differentially expressed lncRNA in AMI were initially screened and target relationship between lncRNA SLC8A1-AS1 and SLC8A1 was then verified. Infarct size, levels of inflammatory factors, biochemical indicators, and the positive expression of the SLC8A1 protein in AMI were subsequently determined. The expression of SLC8A1-AS1, SLC8A1, PKG1, PKG2, atrial natriuretic peptide, and brain natriuretic peptide was detected to assess the effect of SLC8A1-AS1 on SLC8A1 and cGMP-PKG. The respective contents of superoxide dismutase, lactate dehydrogenase (LDH), and malondialdehyde (MDA) were detected accordingly. Microarray data GSE66360 provided evidence indicating that SLC8A1-AS1 was poorly expressed in AMI. SLC8A1 was verified to be a target gene of lncRNA SLC8A1-AS1. SLC8A1-AS1 upregulation decreased levels of left ventricular end-systolic diameter, -dp/ dt _max , interleukin 1β (IL-1β), IL-6, transforming growth factor α, nitric oxide, inducible nitric-oxide synthase, endothelial nitric-oxide synthase, infarct size, LDH activity and MDA content, and increased IL-10, left ventricular end-diastolic pressure and + dp/ dt _max . Furthermore, the overexpression of SLC8A1-AS1 was noted to elicit an inhibitory effect on the cGMP-PKG signaling pathway via SLC8A1. In conclusion, lncRNA SLC8A1-AS1, by downregulating SLC8A1 and activating the cGMP-PKG signaling pathway, was observed to alleviate myocardial damage, inhibit the release of proinflammatory factors and reduce infarct size, ultimately protecting against myocardial damage.

A comparison study of the echocardiographic changes in hypertensive patients treated with telmisartan vs. enalapril

BACKGROUND

Hypertension-induced cardiac dysfunction is variable among different anti-hypertensive medications. This study compares the effects of telmisartan and enalapril on echocardiographic parameters in hypertensive patients.

MATERIALS AND METHODS

This was a randomised single blinded study. Eighty hypertensive patients were included in this study and they were randomly allocated into two study groups: Group 1 included 40 patients who took telmisartan 80mg once daily for six months. Group 2 included 40 patients who took enalapril, 20mg once daily for six months. An additional 40 healthy participants were enrolled in the study as controls (Group 3). Baseline echocardiographic scan was done at the start of the study and after 6 months of treatment including assessment of left ventricular systolic and diastolic functions with assessment of left ventricular mass index, in addition to measurements of blood pressure, heart rate and double product.

RESULTS

Both group 1 and group 2 (telmisartan and enalapril groups respectively) showed comparable statistically significant improvement in the diastolic functional parameters (P<0.010), while both medications didn't demonstrate changes in the systolic functional parameters. Furthermore, telmisartan was significantly effective in reducing the interventricular septal thickness and left ventricular mass index (P<0.010).

CONCLUSIONS

Both drugs interfere with renin-angiotensin aldosterone system, protecting the myocardium from high blood pressure. Findings from our study provide key results for physicians in deciding the appropriate antihypertensive drug for each patient depending based on the patient's intolerability for either medication.