Role of Ranolazine in cardiovascular disease and diabetes: Exploring beyond angina

Roles of non-coding RNA in diabetic cardiomyopathy

In recent years, the incidence of diabetes has been increasing rapidly, posing a serious threat to human health. Diabetic cardiomyopathy (DCM) is characterized by cardiomyocyte hypertrophy, myocardial fibrosis, apoptosis, ventricular remodeling, and cardiac dysfunction in individuals with diabetes, ultimately leading to heart failure and mortality. However, the underlying mechanisms contributing to DCM remain incompletely understood. With advancements in molecular biology technology, accumulating evidence has shown that numerous non-coding RNAs (ncRNAs) crucial roles in the development and progression of DCM. This review aims to summarize recent studies on the involvement of three types of ncRNAs (micro RNA, long ncRNA and circular RNA) in the pathophysiology of DCM, with the goal of providing innovative strategies for the prevention and treatment of DCM.

Improvement of Vascular Insulin Sensitivity by Ranolazine

Ranolazine (RN) is a drug used in the treatment of chronic coronary ischemia. Different clinical trials have shown that RN behaves as an anti-diabetic drug by lowering blood glucose and glycosylated hemoglobin (HbA1c) levels. However, RN has not been shown to improve insulin (IN) sensitivity. Our study investigates the possible facilitating effects of RN on the actions of IN in the rabbit aorta. IN induced vasodilation of the abdominal aorta in a concentration-dependent manner, and this dilatory effect was due to the phosphorylation of endothelial nitric oxide synthase (eNOS) and the formation of nitric oxide (NO). On the other hand, IN facilitated the vasodilator effects of acetylcholine but not the vasodilation induced by sodium nitroprusside. RN facilitated all the vasodilatory effects of IN. In addition, IN decreased the vasoconstrictor effects of adrenergic nerve stimulation and exogenous noradrenaline. Both effects were in turn facilitated by RN. The joint effect of RN with IN induced a significant increase in the ratio of p-eNOS/eNOS and pAKT/AKT. In conclusion, RN facilitated the vasodilator effects of IN, both direct and induced, on the adrenergic system. Therefore, RN increases vascular sensitivity to IN, thus decreasing tissue resistance to the hormone, a key mechanism in the development of type II diabetes.

Calcium and Reactive Oxygen Species Signaling Interplays in Cardiac Physiology and Pathologies

Mitochondria are key players in energy production, critical activity for the smooth functioning of energy-demanding organs such as the muscles, brain, and heart. Therefore, dysregulation or alterations in mitochondrial bioenergetics primarily perturb these organs. Within the cell, mitochondria are the major site of reactive oxygen species (ROS) production through the activity of different enzymes since it is one of the organelles with the major availability of oxygen. ROS can act as signaling molecules in a number of different pathways by modulating calcium (Ca2+) signaling. Interactions among ROS and calcium signaling can be considered bidirectional, with ROS regulating cellular Ca2+ signaling, whereas Ca2+ signaling is essential for ROS production. In particular, we will discuss how alterations in the crosstalk between ROS and Ca2+ can lead to mitochondrial bioenergetics dysfunctions and the consequent damage to tissues at high energy demand, such as the heart. Changes in Ca2+ can induce mitochondrial alterations associated with reduced ATP production and increased production of ROS. These changes in Ca2+ levels and ROS generation completely paralyze cardiac contractility. Thus, ROS can hinder the excitation-contraction coupling, inducing arrhythmias, hypertrophy, apoptosis, or necrosis of cardiac cells. These interplays in the cardiovascular system are the focus of this review.

Prediction of drug-induced liver injury and cardiotoxicity using chemical structure and in vitro assay data

Drug-induced liver injury (DILI) and cardiotoxicity (DICT) are major adverse effects triggered by many clinically important drugs. To provide an alternative to in vivo toxicity testing, the U.S. Tox21 consortium has screened a collection of ∼10K compounds, including drugs in clinical use, against >70 cell-based assays in a quantitative high-throughput screening (qHTS) format. In this study, we compiled reference compound lists for DILI and DICT and compared the potential of Tox21 assay data with chemical structure information in building prediction models for human in vivo hepatotoxicity and cardiotoxicity. Models were built with four different machine learning algorithms (e.g., Random Forest, Naïve Bayes, eXtreme Gradient Boosting, and Support Vector Machine) and model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC-ROC). Chemical structure-based models showed reasonable predictive power for DILI (best AUC-ROC = 0.75 ± 0.03) and DICT (best AUC-ROC = 0.83 ± 0.03), while Tox21 assay data alone only showed better than random performance. DILI and DICT prediction models built using a combination of assay data and chemical structure information did not have a positive impact on model performance. The suboptimal predictive performance of the assay data is likely due to insufficient coverage of an adequately predictive number of toxicity mechanisms. The Tox21 consortium is currently expanding coverage of biological response space with additional assays that probe toxicologically important targets and under-represented pathways that may improve the prediction of in vivo toxicity such as DILI and DICT.

Ranolazine Inhibits Pyroptosis via Regulation of miR-135b in the Treatment of Diabetic Cardiac Fibrosis

Diabetic cardiomyopathy (DCM) is a major cardiovascular complication of diabetes mellitus (DM), and cardiac fibrosis is a characteristic pathological manifestation of DCM. DCM can be exacerbated by pyroptosis, and pyroptosis is a potential target of microRNAs (miRNAs). miR-135b is involved in delaying the progression of numerous cardiovascular diseases, Nonetheless, the role of miR-135b in diabetic cardiac fibrosis is unclear. Ranolazine is a piperazine derivative and is effective for the treatment of cardiovascular disease. The purpose of the study was to elucidate the mechanism of action of ranolazine against diabetic cardiac fibrosis and to investigate the role of miR-135b in this process. Functional and structural changes in the rat heart were examined by echocardiography, hematoxylin-eosin (H&E) and Masson staining. Immunohistochemistry was used to assess the expression of caspase-1, interleukin-1β (IL-1β), gasdermin D (GSDMD), transforming growth factor-β1 (TGF-β1), collagen I and collagen III in the rat left ventricle. Western blot and immunofluorescence were used to detect the protein expression of caspase-1, IL-1β, GSDMD, TGF-β1, collagen I and collagen III proteins, and the mRNA levels were determined using fluorescent quantitative PCR. Ranolazine reduced pyroptosis and inhibited collagen deposition, improving cardiac function in rats. Ranolazine increased miR-135b expression in high glucose-treated cardiac fibroblasts, and miR-135b directly bound to caspase-1. Interference with miR-135b reduced the effects of ranolazine on pyroptosis and collagen deposition. Ranolazine treatment of diabetic cardiac fibrosis inhibited pyroptosis and collagen deposition by upregulating miR-135b. Our study provides a solid theoretical basis for understanding the pathogenesis of diabetic cardiac fibrosis and the clinical use of ranolazine in the treatment of DCM.

Relaxant and antiadrenergic effects of ranolazine in human saphenous vein

OBJECTIVES

Ranolazine improves vascular function in animal models. We evaluate the effects of ranolazine on vascular function and adrenergic response in human saphenous vein.

METHODS

Rings from 53 patients undergoing coronary artery bypass grafting were mounted in organ baths. Concentration-response curves to ranolazine were constructed in rings precontracted with phenylephrine, endothelin-1, vasopressin, KCl and the thromboxane A2 analogue U-46619. In rings precontracted with phenylephrine, relaxation to ranolazine was tested in the absence and presence of endothelial factors inhibitors, K+ channel blockers and verapamil. The effects of ranolazine on frequency-response and concentration-response curves to phenylephrine were performed in the absence and presence of endothelial factors inhibitors and K+ channel blockers. Endothelial nitric oxide synthase, α1 adrenergic receptor and large conductance Ca2+-activated K+ channel protein expressions were measured by Western blotting.

RESULTS

Ranolazine (10-9-10-4 M) produced a concentration-dependent relaxation only in rings precontracted with phenylephrine that was reduced by endothelial denudation, NG-nitro-l-arginine methyl ester (10-4 M), charybdotoxin (10-7 M) and verapamil (10-6 M). Ranolazine diminished adrenergic contractions induced by electrical field stimulation (2-4 Hz) and phenylephrine (10-9-10-5 M) that were prevented by tetraethylammonium (10-3 M) and charybdotoxin (10-7 M). Ranolazine significantly decreased α1 adrenergic receptor and increased large conductance Ca2+-activated K+ channel protein expression in the saphenous vein.

CONCLUSIONS

Ranolazine diminishes the adrenergic vasoconstriction, acting as α1 antagonist, and by increasing large conductance Ca2+-activated K+ channel involvement. The relaxant effects of ranolazine are partially mediated by endothelial nitric oxide, large conductance Ca2+-activated K+ channels and the blockade of voltage-dependent Ca2+ channels.

The Effect of Ranolazine on Glycemic Control: a Narrative Review to Define the Target Population

Ranolazine is an anti-anginal medication that reduces the sodium-dependent calcium overload via the inhibition of the late sodium current. After its approval for the treatment of chronic angina in 2006 in the USA, ranolazine has been reported to have several pleiotropic effects on various cardiac conditions, such as atrial fibrillation, ventricular arrhythmias, diastolic and microvascular dysfunction, and pulmonary arterial hypertension. Recently, several studies reported some promising results on the potential benefits of ranolazine on glycemic control. Though the mechanism of the antihyperglycemic effect is still unknown, ranolazine may exert the effect through β cell preservation, inhibition of glucose secretion, and enhancement of insulin secretion in a glucose-dependent manner. Given the increased risk of cardiovascular disease in patients with diabetes, it will be useful if one medication can simultaneously improve chronic angina and diabetes. Therefore, ranolazine could be a favored choice among other anti-anginal agents for patients with comorbidity of chronic angina and diabetes mellitus. In this review, we summarize the available data from clinical studies and provide valuable insight into defining the target population for the antihyperglycemic effect of ranolazine.

Pathogenesis and pathophysiology of heart failure with reduced ejection fraction: translation to human studies

Heart failure represents the end result of different pathophysiologic processes, which culminate in functional impairment. Regardless of its aetiology, the presentation of heart failure usually involves symptoms of pump failure and congestion, which forms the basis for clinical diagnosis. Pathophysiologic descriptions of heart failure with reduced ejection fraction (HFrEF) are being established. Most commonly, HFrEF is centred on a reactive model where a significant initial insult leads to reduced cardiac output, further triggering a cascade of maladaptive processes. Predisposing factors include myocardial injury of any cause, chronically abnormal loading due to hypertension, valvular disease, or tachyarrhythmias. The pathophysiologic processes behind remodelling in heart failure are complex and reflect systemic neurohormonal activation, peripheral vascular effects and localised changes affecting the cardiac substrate. These abnormalities have been the subject of intense research. Much of the translational successes in HFrEF have come from targeting neurohormonal responses to reduced cardiac output, with blockade of the renin-angiotensin-aldosterone system (RAAS) and beta-adrenergic blockade being particularly fruitful. However, mortality and morbidity associated with heart failure remains high. Although systemic neurohormonal blockade slows disease progression, localised ventricular remodelling still adversely affects contractile function. Novel therapy targeted at improving cardiac contractile mechanics in HFrEF hold the promise of alleviating heart failure at its source, yet so far none has found success. Nevertheless, there are increasing calls for a proximal, 'cardiocentric' approach to therapy. In this review, we examine HFrEF therapy aimed at improving cardiac function with a focus on recent trials and emerging targets.

Cardioprotective effect of ranolazine in nondiabetic and diabetic male rats subjected to isoprenaline-induced acute myocardial infarction involves modulation of AMPK and inhibition of apoptosis

Diabetes increases the sensitivity of myocardium to ischemic damage and impairs response of the myocardium to cardioprotective interventions. The present study aimed to elucidate the potential cardioprotective effect provided by ranolazine during myocardial infarction in nondiabetic and diabetic male rats. As AMP-activated protein kinase (AMPK) has been shown to be involved in the cellular response to ischemic injury, in this context, the present animal study evaluated the modulating role of ranolazine in the AMPK expression in isoprenaline-induced myocardial ischemic rat model. Male rats were divided into 2 experiments: experiment I and II (nondiabetic and diabetic rats) and assigned to normal control, saline control for isoprenaline, isoprenaline control, and ranolazine-treated groups. Ranolazine administration revealed effectiveness in attenuating the severity of isoprenaline-induced myocardial injury in both nondiabetic and diabetic rats as revealed by ECG signs, histopathological score, and apoptotic markers via abrogating the increments in the inflammatory and oxidative stress markers and modulating AMPK expression. Therefore, the current cardioprotective effect of ranolazine was, at least in part, mediated through inhibition of apoptosis and modulation of AMPK expression, encouraging considering the utility of ranolazine in protection from acute myocardial infarction.

Ranolazine: Multifaceted Role beyond Coronary Artery Disease, a Recent Perspective

Ranolazine is a piperazine derivative approved as an antianginal. Primarily used as a second-line antianginal in stable coronary artery disease. Ranolazine blocks the late Na + current and prevents the rise of cytosolic calcium. It decreases myocardial wall tension and improves coronary blood flow. Ranolazine is effective in atrial fibrillation (AF) as an adjunct to electrical or pharmacological cardioversion. It can be used in combination with amiodarone or dronedarone. It has also been used in AF arising after coronary artery bypass grafting surgery. Role of ranolazine is also being evaluated in pulmonary arterial hypertension, diastolic dysfunction, and chemotherapy-induced cardiotoxicity. Ranolazine has some anti-glycemic effect and has shown a reduction of hemoglobin A1c in multiple trials. The antianginal effect of ranolazine has also been seen to be more in patients with diabetes compared to those without diabetes. Ranolazine is being evaluated in patients with the peripheral arterial disease with intermittent claudication and hypertrophic cardiomyopathy. Pilot studies have shown that ranolazine may be beneficial in neurological conditions with myotonia. The evidence-base on the use of ranolazine in various conditions is rapidly increasing with results of further trials eagerly awaited. Accumulating evidence may see ranolazine in routine clinical use for many conditions beyond its traditional role as an antianginal.

Empagliflozin Ammeliorates High Glucose Induced-Cardiac Dysfuntion in Human iPSC-Derived Cardiomyocytes

Empagliflozin, a sodium-glucose co-transporter (SGLT) inhibitor, reduces heart failure and sudden cardiac death but the underlying mechanisms remain elusive. In cardiomyocytes, SGLT1 and SGLT2 expression is upregulated in diabetes mellitus, heart failure, and myocardial infarction. We hypothesise that empagliflozin exerts direct effects on cardiomyocytes that attenuate diabetic cardiomyopathy. To test this hypothesis, cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) were used to test the potential effects of empagliflozin on neutralization of cardiac dysfunction induced by diabetic-like cultures. Our results indicated that insulin-free high glucose culture significantly increased the size of and NPPB, SGLT1 and SGLT2 expression of hiPSC-derived cardiomyocytes. In addition, high glucose-treated hiPSC-derived cardiomyocytes exhibited reduced contractility regardless of the increased calcium transient capacity. Interestingly, application of empagliflozin before or after high glucose treatment effectively reduced the high glucose-induced cardiac abnormalities. Since application of empagliflozin did not significantly alter viability or glycolytic capacity of the hiPSC-derived cardiomyocytes, it is plausible that empagliflozin exerts its effects via the down-regulation of SGLT1, SGLT2 and GLUT1 expression. These observations provide supportive evidence that may help explain its unexpected benefit observed in the EMPA-REG trial.

Targeting Mitochondrial Calcium Handling and Reactive Oxygen Species in Heart Failure

PURPOSE OF REVIEW

In highly prevalent cardiac diseases, new therapeutic approaches are needed. Since the first description of oxidative stress in heart failure, reactive oxygen species (ROS) have been considered as attractive drug targets. Though clinical trials evaluating antioxidant vitamins as ROS-scavenging agents yielded neutral results in patients at cardiovascular risk, the knowledge of ROS as pathophysiological factors has considerably advanced in the past few years and led to novel treatment approaches. Here, we review recent new insights and current strategies in targeting mitochondrial calcium handling and ROS in heart failure.

RECENT FINDINGS

Mitochondria are an important ROS source, and more recently, drug development focused on targeting mitochondria (e.g. by SS-31 or MitoQ). Important advancement has also been made to decipher how the matching of energy supply and demand through calcium (Ca²⁺) handling impacts on mitochondrial ROS production and elimination. This opens novel opportunities to ameliorate mitochondrial dysfunction in heart failure by targeting cytosolic and mitochondrial ion transporters to improve this matching process. According to this approach, highly specific substances as the preclinical CGP-37157, as well as the clinically used ranolazine and empagliflozin, provide promising results on different levels of evidence. Furthermore, the understanding of redox signalling relays, resembled by catalyst-mediated protein oxidation, is about to change former paradigms of ROS signalling. Novel methods, as redox proteomics, allow to precisely analyse key regulatory thiol switches, which may induce adaptive or maladaptive signalling. Additionally, the generation of genetically encoded probes increased the spatial and temporal resolution of ROS imaging and opened a new methodological window to subtle, formerly obscured processes. These novel insights may broaden our understanding of why previous attempts to target oxidative stress have failed, and at the same time provide us with new targets for drug development.

Efficacy and Safety of Ranolazine in Diabetic Patients: A Systematic Review and Meta-analysis

BACKGROUND

Recent studies have discovered that the antiangina agent ranolazine exerts a glucometabolic effect.

OBJECTIVE

This systematic review and meta-analysis aimed to further understand the efficacy and safety profile of ranolazine in patients with diabetes.

METHODS

Randomized controlled trials (RCTs) were searched in PubMed, Cochrane, and EMBASE databases and in ClinicalTrials.gov up to July 2017. Efficacy end points were defined as the change in hemoglobin A1C (A1C) and fasting serum glucose (FSG) levels. Safety end points included the incidence of hypoglycemia, persistent hyperglycemia, and major adverse cardiovascular events (MACE). Sensitive and subgroup analyses were also conducted.

RESULTS

Seven RCTs with 4461 diabetic patients were selected. Compared with placebo, the use of ranolazine significantly reduced the levels of A1C (weighted mean difference [WMD] = -0.49%; 95% CI = -0.58 to -0.40; P < 0.00001) and FSG (WMD = -6.70 mg/dL; 95% CI = -11.87 to -1.52; P = 0.01). No significant differences were observed in the rates of hypoglycemia (relative risk [RR] = 1.17; 95% CI = 0.76 to 1.80; P = 0.47), persistent hyperglycemia (RR = 0.78; 95% CI = 0.47 to 1.31; P = 0.35), and MACE (RR = 0.65; 95% CI = 0.32 to 1.32; P = 0.23).

CONCLUSION

Ranolazine exerts a positive effect on glucose control and is a well-tolerated agent for patients with diabetes.

Effects of ranolazine in a model of doxorubicin-induced left ventricle diastolic dysfunction

BACKGROUND AND PURPOSE

Doxorubicin is a highly effective anticancer drug, but its clinical application is hampered by cardiotoxicity. Asymptomatic diastolic dysfunction can be the earliest manifestation of doxorubicin cardiotoxicity. Therefore, a search for therapeutic intervention that can interfere with early manifestations and possibly prevent later development of cardiotoxicity is warranted. Increased doxorubicin-dependent ROS may explain, in part, Ca²⁺ and Na⁺ overload that contributes to diastolic dysfunction and development of heart failure. Therefore, we tested whether the administration of ranolazine, a selective blocker of late Na⁺ current, immediately after completing doxorubicin therapy, could affect diastolic dysfunction and interfere with the progression of functional decline.

EXPERIMENTAL APPROACH

Fischer 344 rats received a cumulative dose of doxorubicin of 15 mg·kg^-1 over a period of 2 weeks. After the assessment of diastolic dysfunction, the animals were treated with ranolazine (80 mg·kg^-1 , daily) for the following 4 weeks.

KEY RESULTS

While diastolic and systolic function progressively deteriorated in doxorubicin-treated animals, treatment with ranolazine relieved diastolic dysfunction and prevented worsening of systolic function, decreasing mortality. Ranolazine lowered myocardial NADPH oxidase 2 expression and oxidative/nitrative stress. Expression of the Na⁺ /Ca²⁺ exchanger 1 and Na_v 1.5 channels was reduced and of the sarcoplasmic/endoplasmic reticulum Ca²⁺ -ATPase 2 protein was increased. In addition, ranolazine lowered doxorubicin-induced hyper-phosphorylation and oxidation of Ca²⁺ /calmodulin-dependent protein kinase II, and decreased myocardial fibrosis.

CONCLUSIONS AND IMPLICATIONS

Ranolazine, by the increased Na⁺ influx, induced by doxorubicin, altered cardiac Ca²⁺ and Na⁺ handling and attenuated diastolic dysfunction induced by doxorubicin, thus preventing the progression of cardiomyopathy.

LINKED ARTICLES

This article is part of a themed section on New Insights into Cardiotoxicity Caused by Chemotherapeutic Agents. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.21/issuetoc.