Nicorandil prevents Gαq-induced progressive heart failure and ventricular arrhythmias in transgenic mice

Nicorandil as a promising therapeutic option for ventricular arrhythmia: A case report and review of literature

BACKGROUND

Ventricular arrhythmia is a common type of arrhythmia observed in clinical practice. It is primarily characterized by premature ventricular contractions, ventricular tachycardia, and ventricular fibrillation. Abnormal formation or transmission of cardiac electrical impulses in patients affects cardiac ejection function. It may present with symptoms such as palpitations, dyspnea, chest discomfort, and reduced exercise tolerance. In severe cases, ventricular arrhythmia can even lead to death. Therefore, prompt treatment is very much essential upon diagnosis. The symptoms did not improve after previous conventional drugs and electrical defibrillation treatment, but the ventricular arrhythmia was prevented after the addition of nicorandil.

CASE SUMMARY

A 75-year-old female patient was admitted to the hospital because of intermittent chest tightness, shortness of breath for 10 days, and fainting once for 7 days. Combined with laboratory tests and auxiliary examination, the patient was tentatively diagnosed with coronary heart disease or arrhythmia-atrial fibrillation. After admission, the patient had intermittent ventricular arrhythmia, which was uncontrolled with lidocaine, defibrillation, and amiodarone. However, when she was treated with nicorandil, the ventricular arrhythmia stopped. Nicorandil mitigates the action potential duration by facilitating the opening of potassium ion channels, thereby regulating the likelihood of premature and delayed depolarization in two distinct phases and subsequently averting the onset of malignant ventricular arrhythmia. Nicorandil may inhibit ventricular arrhythmia by dilating coronary arteries, improving coronary microcirculation and reducing myocardial fibrosis.

CONCLUSION

Nicorandil is a drug with dual effects. It could be used as a new therapeutic option for inhibiting ventricular arrhythmias.

Intravenous nicorandil for patients with acute decompensated heart failure: a meta-analysis of randomized controlled trials

OBJECTIVES

Pilot studies have suggested the potential benefits of intravenous nicorandil for patients with acute decompensated heart failure (ADHF). However, clinical evidence remains limited. The aim of the study was to summarize the efficacy and safety of intravenous nicorandil for the treatment of ADHF.

DESIGN

A systematic review and meta-analysis was performed. The search for relevant randomised controlled trials (RCTs) was conducted in PubMed, Embase, Cochrane's Library, Wanfang, and CNKI databases. A random-effects model was employed to combine the results.

RESULTS

Eight RCTs contributed to the meta-analysis. Pooled results showed that acute treatment with intravenous nicorandil could significantly improve the symptom of dyspnea at 24 h after treatment, as evidenced by the five-point Likert scale for dyspnea after treatment (mean difference [MD]: -0.26, 95% confidence interval [CI]: -0.40 to -0.13, p < 0.001). Furthermore, nicorandil significantly reduced serum B natriuretic peptide (MD: -30.03 ng/dl, 95% CI: -47.00 to -13.06, p < 0.001), and N-terminal proBNP (MD: -138.69, 95% CI: -248.06 to -29.31, p = 0.01). In addition, nicorandil significantly improved ultrasonic parameters including left ventricular ejection fraction and E/e' at discharge. Moreover, during the follow-up duration of up to 90 days, intravenous nicorandil significantly reduced the incidence of major adverse cardiovascular events (risk ratio [RR]: 0.55, 95% CI: 0.32 to 0.93, p = 0.03). The incidence of treatment-related adverse events was not significantly different between nicorandil and controls (RR: 1.22, 95% CI: 0.69 to 2.15, p = 0.49).

CONCLUSIONS

Results of this study suggest that intravenous nicorandil may be an effective and safe treatment for patients with ADHF.

Cardioprotective effect of nicorandil on isoproterenol induced cardiomyopathy in the Mdx mouse model

BACKGROUND

Duchenne muscular dystrophy (DMD) associated cardiomyopathy is a major cause of morbidity and mortality. In an in vitro DMD cardiomyocyte model, nicorandil reversed stress-induced cell injury through multiple pathways implicated in DMD. We aimed to test the efficacy of nicorandil on the progression of cardiomyopathy in mdx mice following a 10-day treatment protocol.

METHODS

A subset of mdx mice was subjected to low-dose isoproterenol injections over 5 days to induce a cardiac phenotype and treated with vehicle or nicorandil for 10 days. Baseline and day 10 echocardiograms were obtained to assess cardiac function. At 10 days, cardiac tissue was harvested for further analysis, which included histologic analysis and assessment of oxidative stress. Paired student's t test was used for in group comparison, and ANOVA was used for multiple group comparisons.

RESULTS

Compared to vehicle treated mice, isoproterenol decreased ejection fraction and fractional shortening on echocardiogram. Nicorandil prevented isoproterenol induced cardiac dysfunction. Isoproterenol increased cardiac fibrosis, which nicorandil prevented. Isoproterenol increased gene expression of NADPH oxidase, which decreased to baseline with nicorandil treatment. Superoxide dismutase 2 protein expression increased in those treated with nicorandil, and xanthine oxidase activity decreased in mice treated with nicorandil during isoproterenol stress compared to all other groups.

CONCLUSIONS

In conclusion, nicorandil is cardioprotective in mdx mice and warrants continued investigation as a therapy for DMD associated cardiomyopathy.

Agents with vasodilator properties in acute heart failure

Millions of patients worldwide are admitted for acute heart failure (AHF) each year and physicians caring for these patients are confronted with the short-term challenges of reducing symptoms while preventing end organ dysfunction without causing additional harm, and the intermediate-term challenges of improving clinical outcomes such as hospital readmission and survival. There are limited data demonstrating the efficacy of any currently available therapies for AHF to meet these goals. After diuretics, vasodilators are the most common intravenous therapy for AHF, but neither nitrates, nitroprusside, nor nesiritide have robust evidence supporting their ability to provide meaningful effects on clinical outcomes, except perhaps early symptom improvement. Recently, a number of novel agents with vasodilating properties have been developed for the treatment of AHF. These agents include serelaxin, natriuretic peptides (ularitide, cenderitide), β-arrestin-biased angiotensin II type 1 receptor ligands (TRV120027), nitroxyl donors (CXL-1020, CXL-1427), soluble guanylate cyclase modulators (cinaciguat, vericiguat), short-acting calcium channel blockers (clevidipine), and potassium channel activators (nicorandil). These development programmes range from the stage of early dose-finding studies (e.g. TRV120027, CXL-1427) to large, multicentre mortality trials (e.g. serelaxin, ularitide). There is an urgent need for agents with vasodilating properties that will improve both in-hospital and post-discharge clinical outcomes, and these novel approaches may provide opportunities to address this need.

Nicorandil alleviates myocardial injury and post-infarction cardiac remodeling by inhibiting Mst1

BACKGROUND

Cardiomyocyte autophagy and apoptosis are crucial events underlying the development of cardiac abnormalities and dysfunction after myocardial infarction (MI). A better understanding of the cell signaling pathways involved in cardiac remodeling may support the development of new therapeutic strategies for the treatment of heart failure (HF) after MI.

METHODS

A cardiac MI injury model was constructed by ligating the left anterior descending (LAD) coronary artery. Neonatal cardiomyocytes were isolated and cultured to investigate the mechanisms underlying the protective effects of nicorandil on MI-induced injury.

RESULTS

Nicorandil reduced cardiac enzyme release, mitigated left ventricular enlargement and cardiac dysfunction after MI, as evaluated by echocardiography and hemodynamic measurements. According to the results of the western blot analysis and immunofluorescence staining, nicorandil enhanced autophagic flux and reduced apoptosis in cardiomyocytes subjected to hypoxic injury. Interestingly, nicorandil increased Mst1 and p-Mst1 levels in cardiomyocytes subjected to MI injury. Mst1 knockout abolished the protective effects of nicorandil on cardiac remodeling and dysfunction after MI. Mst1 knockout also abolished the beneficial effects of nicorandil on cardiac enzyme release and cardiomyocyte autophagy and apoptosis.

CONCLUSIONS

Nicorandil alleviates post-MI cardiac dysfunction and remodeling. The mechanisms were associated with enhancing autophagy and inhibiting apoptosis through Mst1 inhibition.

Activation of ATP-sensitive potassium channels facilitates the function of human endothelial colony-forming cells via Ca2+ /Akt/eNOS pathway

Accumulating data, including those from our laboratory, have shown that the opening of ATP‐sensitive potassium channels (K_ATP) plays a protective role in pulmonary vascular diseases (PVD). As maintainers of the endothelial framework, endothelial colony‐forming cells (ECFCs) are considered excellent candidates for vascular regeneration in cases of PVD. Although K_ATP openers (KCOs) have been demonstrated to have beneficial effects on endothelial cells, the impact of K_ATP on ECFC function remains unclear. Herein, this study investigated whether there is a distribution of K_ATP in ECFCs and what role K_ATP play in ECFC modulation. By human ECFCs isolated from adult peripheral blood, K_ATP were confirmed for the first time to express in ECFCs, comprised subunits of Kir (Kir6.1, Kir6.2) and SUR2b. KCOs such as the classical agent nicorandil (Nico) and the novel agent iptakalim (Ipt) notably improved the function of ECFCs, promoting cell proliferation, migration and angiogenesis, which were abolished by a non‐selective K_ATP blocker glibenclamide (Gli). To determine the underlying mechanisms, we investigated the impacts of KCOs on CaMKII, Akt and endothelial nitric oxide synthase pathways. Enhanced levels were detected by western blotting, which were abrogated by Gli. This suggested an involvement of Ca²⁺ signalling in the regulation of ECFCs by K_ATP. Our findings demonstrated for the first time that there is a distribution of K_ATP in ECFCs and K_ATP play a vital role in ECFC function. The present work highlighted a novel profile of K_ATP as a potential target for ECFC modulation, which may hold the key to the treatment of PVD.

Nicorandil enhances the efficacy of mesenchymal stem cell therapy in isoproterenol-induced heart failure in rats

Stem cell transplantation has emerged as a promising technique for regenerative medicine in cardiovascular therapeutics. However, the results have been less than optimal. The aim of the present study was to investigate whether nicorandil could offer an additional benefit over bone marrow-derived mesenchymal stem cell therapy in isoproterenol-induced myocardial damage and its progression to heart failure in rats. Isoproterenol was injected subcutaneously for 2 consecutive days at doses of 85 and 170 mg/kg/day, respectively. Nicorandil (3 mg/kg/day) was then given orally with or without a single intravenous bone marrow-derived mesenchymal stem cell administration. Electrocardiography and echocardiography were recorded 2 weeks after the beginning of treatment. Rats were then sacrificed and the ventricle was isolated for estimation of tumor necrosis factor-alpha, vascular endothelial growth factor and transforming growth factor-beta. Moreover, protein expressions of caspase-3, connexin-43 as well as endothelial and inducible nitric oxide synthases were evaluated. Finally, histological studies of myocardial fibrosis and blood vessel density were performed and cryosections were done for estimation cell homing. Combined nicorandil/bone marrow-derived mesenchymal stem cell therapy provided an additional improvement compared to cell therapy alone toward reducing isoproterenol-induced cardiac hypertrophy, fibrosis and inflammation. Notably, combined therapy induced significant increase in angiogenesis and cell homing and prevented isoproterenol-induced changes in contractility and apoptotic markers. In conclusion, combined nicorandil/bone marrow-derived mesenchymal stem cell therapy was superior to cell therapy alone toward preventing isoproterenol-induced heart failure in rats through creation of a supportive environment for mesenchymal stem cells.

Cardiac overexpression of constitutively active Galpha q causes angiotensin II type1 receptor activation, leading to progressive heart failure and ventricular arrhythmias in transgenic mice

BACKGROUND

Transgenic mice with transient cardiac expression of constitutively active Galpha q (Gαq-TG) exhibt progressive heart failure and ventricular arrhythmias after the initiating stimulus of transfected constitutively active Gαq becomes undetectable. However, the mechanisms are still unknown. We examined the effects of chronic administration of olmesartan on heart failure and ventricular arrhythmia in Gαq-TG mice.

METHODOLOGY/PRINCIPAL FINDINGS

Olmesartan (1 mg/kg/day) or vehicle was chronically administered to Gαq-TG from 6 to 32 weeks of age, and all experiments were performed in mice at the age of 32 weeks. Chronic olmesartan administration prevented the severe reduction of left ventricular fractional shortening, and inhibited ventricular interstitial fibrosis and ventricular myocyte hypertrophy in Gαq-TG. Electrocardiogram demonstrated that premature ventricular contraction (PVC) was frequently (more than 20 beats/min) observed in 9 of 10 vehicle-treated Gαq-TG but in none of 10 olmesartan-treated Gαq-TG. The collected QT interval and monophasic action potential duration in the left ventricle were significantly shorter in olmesartan-treated Gαq-TG than in vehicle-treated Gαq-TG. CTGF, collagen type 1, ANP, BNP, and β-MHC gene expression was increased and olmesartan significantly decreased the expression of these genes in Gαq-TG mouse ventricles. The expression of canonical transient receptor potential (TRPC) 3 and 6 channel and angiotensin converting enzyme (ACE) proteins but not angiotensin II type 1 (AT1) receptor was increased in Gαq-TG ventricles compared with NTG mouse ventricles. Olmesartan significantly decreased TRPC6 and tended to decrease ACE expressions in Gαq-TG. Moreover, it increased AT1 receptor in Gαq-TG.

CONCLUSIONS/SIGNIFICANCE

These findings suggest that angiotensin II type 1 receptor activation plays an important role in the development of heart failure and ventricular arrhythmia in Gαq-TG mouse model of heart failure.

Nicorandil improves electrical remodelling, leading to the prevention of electrically induced ventricular tachyarrhythmia in a mouse model of desmin-related cardiomyopathy

1. Transgenic (TG) mice overexpressing an arg120gly missense mutation in heat shock protein B5 (HSPB5; i.e. R120G TG mice) exhibit desmin-related cardiomyopathy. Recently, the cardioprotective effect of nicorandil has been shown to prolong the survival of R120G TG mice. However, whether the TG mice exhibit ventricular arrhythmias and whether nicorandil can inhibit these arrhythmias remain unknown. In the present study we examined the effects of chronic nicorandil administration on ventricular electrical remodelling and arrhythmias in R120G TG mice. 2. Mice were administered nicorandil (15 mg/kg per day) or vehicle (water) orally from 5 to 30 weeks of age. Electrocardiograms (ECG) and optical action potentials were recorded from R120G TG mouse hearts. In addition, the expression of ventricular connexin 43 and the cardiac Na(+) channel Nav1.5 was examined in TG mice. 3. All ECG parameters tested were prolonged in R120G TG compared with non-transgenic (NTG) mice. Nicorandil improved the prolonged P, PQ and QRS intervals in R120G TG mice. Interestingly, impulse conduction slowing and increases in the expression of total and phosphorylated connexin 43 and Nav1.5 were observed in ventricles from R120G TG compared with NTG mice. Nicorandil improved ventricular impulse conduction slowing and normalized the increased protein expression levels of total and phosphorylated connexin 43, but not of Nav1.5, in R120G TG mouse hearts. Electrical rapid pacing at the ventricle induced ventricular tachyarrhythmias (VT) in six of eight R120G TG mouse hearts, but not in any of the eight nicorandil-treated R120G TG mouse hearts (P < 0.05). 4. These findings demonstrate that nicorandil inhibits cardiac electrical remodelling and that the prevention of VT by nicorandil is associated with normalization of connexin 43 expression in this model.