Resveratrol enhances the inotropic effect but inhibits the proarrhythmic effect of sympathomimetic agents in rat myocardium

Natural Substances vs. Approved Drugs in the Treatment of Main Cardiovascular Disorders-Is There a Breakthrough?

Cardiovascular diseases (CVDs) are a group of diseases with a very high rate of morbidity and mortality. The clinical presentation of CVDs can vary from asymptomatic to classic symptoms such as chest pain in patients with myocardial infarction. Current therapeutics for CVDs mainly target disease symptoms. The most common CVDs are coronary artery disease, acute myocardial infarction, atrial fibrillation, chronic heart failure, arterial hypertension, and valvular heart disease. In their treatment, conventional therapies and pharmacological therapies are used. However, the use of herbal medicines in the therapy of these diseases has also been reported in the literature, resulting in a need for critical evaluation of advances related to their use. Therefore, we carried out a narrative review of pharmacological and herbal therapeutic effects reported for these diseases. Data for this comprehensive review were obtained from electronic databases such as MedLine, PubMed, Web of Science, Scopus, and Google Scholar. Conventional therapy requires an individual approach to the patients, as when patients do not respond well, this often causes allergic effects or various other unwanted effects. Nowadays, medicinal plants as therapeutics are frequently used in different parts of the world. Preclinical/clinical pharmacology studies have confirmed that some bioactive compounds may have beneficial therapeutic effects in some common CVDs. The natural products analyzed in this review are promising phytochemicals for adjuvant and complementary drug candidates in CVDs pharmacotherapy, and some of them have already been approved by the FDA. There are insufficient clinical studies to compare the effectiveness of natural products compared to approved therapeutics for the treatment of CVDs. Further long-term studies are needed to accelerate the potential of using natural products for these diseases. Despite this undoubted beneficence on CVDs, there are no strong breakthroughs supporting the implementation of natural products in clinical practice. Nevertheless, they are promising agents in the supplementation and co-therapy of CVDs.

Chinese herbal medicine for the treatment of cardiovascular diseases ─ targeting cardiac ion channels

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality, imposing an increasing global health burden. Cardiac ion channels (voltage-gated Na_V, Ca_V, K_Vs, and others) synergistically shape the cardiac action potential (AP) and control the heartbeat. Dysfunction of these channels, due to genetic mutations, transcriptional or post-translational modifications, may disturb the AP and lead to arrhythmia, a major risk for CVD patients. Although there are five classes of anti-arrhythmic drugs available, they can have varying levels of efficacies and side effects on patients, possibly due to the complex pathogenesis of arrhythmias. As an alternative treatment option, Chinese herbal remedies have shown promise in regulating cardiac ion channels and providing anti-arrhythmic effects. In this review, we first discuss the role of cardiac ion channels in maintaining normal heart function and the pathogenesis of CVD, then summarize the classification of Chinese herbal compounds, and elaborate detailed mechanisms of their efficacy in regulating cardiac ion channels and in alleviating arrhythmia and CVD. We also address current limitations and opportunities for developing new anti-CVD drugs based on Chinese herbal medicines.

Research Progress on Natural Products’ Therapeutic Effects on Atrial Fibrillation by Regulating Ion Channels

Antiarrhythmic drugs (AADs) have a therapeutic effect on atrial fibrillation (AF) by regulating the function of ion channels. However, several adverse effects and high recurrence rates after drug withdrawal seriously affect patients’ medication compliance and clinical prognosis. Thus, safer and more effective drugs are urgently needed. Active components extracted from natural products are potential choices for AF therapy. Natural products like Panax notoginseng (Burk.) F.H. Chen, Sophora flavescens Ait., Stephania tetrandra S. Moore., Pueraria lobata (Willd.) Ohwi var. thomsonii (Benth.) Vaniot der Maesen., and Coptis chinensis Franch. have a long history in the treatment of arrhythmia, myocardial infarction, stroke, and heart failure in China. Based on the classification of chemical structures, this article discussed the natural product components’ therapeutic effects on atrial fibrillation by regulating ion channels, connexins, and expression of related genes, in order to provide a reference for development of therapeutic drugs for atrial fibrillation.

Cardioprotection stimulated by resveratrol and grape products prevents lethal cardiac arrhythmias in an animal model of ischemia and reperfusion

PURPOSE

To evaluate the preventive cardioprotective effects of resveratrol and grape products, such as grape juice and red wine, in animal model of cardiac ischemia and reperfusion.

METHODS

Male Wistar rats orally pretreated for 21-days with resveratrol and grape products were anesthetized and placed on mechanical ventilation to surgically induce cardiac ischemia and reperfusion by obstruction (ischemia) followed by liberation (reperfusion) of blood circulation in left descending coronary artery. These rats were submitted to the electrocardiogram (ECG) analysis to evaluate the effects of pretreatment with resveratrol and grape products on the incidence of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) resulting from cardiac ischemia and reperfusion.

RESULTS

It was observed that the incidence of AVB was significantly lower in rats pretreated with resveratrol (25%), grape juice (37.5%) or red wine (12.5%) than in rats treated with saline solution (80%) or ethanol (80%). Similarly, incidence of LET was also significantly lower in rats pretreated with resveratrol (25%), grape juice (25%) or red wine (0%) than in rats treated with saline solution (62.5%) or ethanol (75%).

CONCLUSIONS

These results indicate that the cardioprotective response stimulated by resveratrol and grape products prevents the lethal cardiac arrhythmias in animal model of ischemia and reperfusion, supporting the idea that this treatment can be beneficial for prevention of severe cardiac arrhythmias in patients with ischemic heart disease.

Mitochondrial Dysfunction Increases Arrhythmic Triggers and Substrates; Potential Anti-arrhythmic Pharmacological Targets

Incidence of cardiac arrhythmias increases significantly with age. In order to effectively stratify arrhythmic risk in the aging population it is crucial to elucidate the relevant underlying molecular mechanisms. The changes underlying age-related electrophysiological disruption appear to be closely associated with mitochondrial dysfunction. Thus, the present review examines the mechanisms by which age-related mitochondrial dysfunction promotes arrhythmic triggers and substrate. Namely, via alterations in plasmalemmal ionic currents (both sodium and potassium), gap junctions, cellular Ca²⁺ homeostasis, and cardiac fibrosis. Stratification of patients' mitochondrial function status permits application of appropriate anti-arrhythmic therapies. Here, we discuss novel potential anti-arrhythmic pharmacological interventions that specifically target upstream mitochondrial function and hence ameliorates the need for therapies targeting downstream changes which have constituted traditional antiarrhythmic therapy.

St. Thomas and del Nido cardioplegia are superior to Custodiol cardioplegia in a rat model of donor heart

OBJECTIVES

Cardiac transplantation is an effective treatment for advanced heart disease and protection of the donor organ is directly associated with post-transplantation outcomes. Cardioplegic strategies intend to protect the donor heart against ischemic injury during transplantation procedures. In our study, the effects of three different cardioplegia solutions were evaluated in a rat heart donor model in terms of cellular base. Design. Cardioplegia solutions as St. Thomas, del Nido or Custodiol were administered to male Wistar albino rats until cardiac arrest. Arrested hearts were excised and incubated in cold cardioplegia solutions for 4 h. Organ bath experiments were performed using the right ventricular free wall strips of the heart tissues. ATP, sialic acid, TNF-α levels and MMP-9 activities were measured in heart tissues. Incubation media were also used to measure TNF-α and troponin-I levels following organ baths experiments. Results. Custodiol administration led to reduced myocardial contraction (p < .05), decreased ATP levels (p < .001) and increased both TNF-α levels (p < .05), and MMP-9 activity (p < .05). Additionally, troponin-I and TNF-α levels in media were significantly increased (p < .05), TNF-α levels were positively correlated with MMP-9 activities (r = .93, p = .007) and negatively correlated with ATP levels (r = -.91, p = .01) in the Custodiol group. Also, MMP-9 activities were negatively correlated with ATP levels (r = -.90, p = .01) Conclusion. Custodiol cardioplegia cannot prevent functional and cellular damage in donor heart tissue. St. Thomas or del Nido cardioplegia could result in superior functional and biochemical improvement during transplantation procedures. In this respect, these cardioplegic solutions may be more advantageous as cellular and functional.

Multicomponent self nano emulsifying delivery systems of resveratrol with enhanced pharmacokinetics profile

Resveratrol is a drug with high potential for clinical application based on experimental models. Though, resveratrol translation to clinical use has not been successful yet due to its poor pharmacokinetics, related to poor solubility and fast metabolism. The use of drug delivery systems, namely self-emulsifying drug delivery systems (SEDDS), may be a viable strategy to overcome the poor in vivo performance of resveratrol. In this work, a rational development of two different ternary SEDDS was conducted. Experimental data showed that quantitative variations on SEDDS composition impacted dispersion and robustness to dilution of SEDDS, as well as loading capacity and droplet size. Formulations composed of Lauroglycol® 90/Labrasol®/Capryol® PGMC (12.5/75.0/12.5) (Lau/Lab/Cap) and Tween® 80/Transcutol®/Imwitor® 742 (33.3/33.3/33.3) (T80/Trans/Imw) featured improved performance and were selected for further studies. T80/Trans/Imw formulation yield faster emulsification and originated smaller droplet size, with lower cumulative percentile of 90% of particles (D₉₀) (below 200 nm), as compared to the than Lau/Lab/Cap formulation. Higher resveratrol permeation rate was observed in Caco-2 cell monolayer permeability studies for both formulations as compared to the free drug. Reduction of the metabolization and/or efflux of resveratrol was also noticed in the case of SEDDs, as suggested by the increased recovery of total drug. Plasmatic drug concentrations in rats observed after oral gavage indicate that both formulations provided faster resveratrol absorption than free drug, resulting in shorter T_max values (30 min vs. 2 h). No statistically significant differences were observed for AUC_0-t values of both formulations and the free drug. Still, C_max for the Lau/Lab/Cap SEDDs formulation was 2-fold higher than for the free drug. These findings suggest that SEDDS can increase resveratrol solubility and reduce its metabolization, resulting in an overall improvement of its oral pharmacokinetics profile.

Vasodilatory Efficacy and Impact of Papaverine on Endothelium in Radial Artery Predilatation for CABG Surgery: in Search for Optimal Concentration

OBJECTIVE

The aim of this study was to compare the efficacy of two different papaverine concentrations (0.5 mg/ml and 2 mg/ml) for vasospasm prevention and their impact on endothelium integrity.

METHODS

We have studied distal segments of radial arteries obtained by no-touch technique from coronary artery bypass graft (CABG) patients (n=10). The vasodilatory effect of papaverine (concentrations of 0.5 mg/ml and 2 mg/ml) was assessed in vitro, in isometric tension studies using ex vivo myography (organ bath technique) and arterial rings precontracted with potassium chloride (KCl) and phenylephrine. The impact of papaverine on endothelial integrity was studied by measurement of the percentage of vessel's circumference revealing CD34 endothelial marker.

RESULTS

2 mg/ml papaverine concentration showed stronger vasodilatatory effect than 0.5 mg/ml, but it caused significantly higher endothelial damage. Response to KCl was 7.35±3.33 mN for vessels protected with papaverine 0.5 mg/ml and 2.66±1.96 mN when papaverine in concentration of 2 mg/ml was used. The histological examination revealed a significant difference in the presence of undamaged endothelium between vessels incubated in papaverine 0.5 mg/ml (72.86±9.3%) and 2 mg/ml (50.23±13.42%), P=0.002.

CONCLUSION

Papaverine 2 mg/ml caused the higher endothelial damage. Concentration of 0.5 mg/ml caused better preservation of the endothelial lining.

Apelin protects against myocardial ischemic injury by inhibiting dynamin-related protein 1

It is known that dynamin-related protein 1 (Drp1)-mediated mitochondrial fission plays an important role in ischemic injury of myocardial infarction (MI). Apelin, an endogenous ligand for Apelin receptor, acts as a key modulator of cardiovascular diseases. Here, we examined the effects of Apelin on MI injury and underlying mechanisms. Adult male C57BL/6J mice were treated with Apelin for 4 weeks and then subjected coronary artery ligation (LAD) to induce MI and the protective effects of Apelin on MI injury were evaluated at 6 h post LAD. Mitochondrial fission was significantly increased in MI as evidenced by enhanced expression of phosphorylated Drp1 (p-Drp1^{ser 616}) without affecting total Drp-1 level and degenerative transformation of mitochondria into short rods as typical fission. Apelin markedly inhibited p-Drp1^{ser 616} and preserved mitochondrial morphology in MI. Similar effects of Apelin were consistently observed in primary cultured cardiomyocytes under hypoxia. Apelin decreased hypoxia-induced cardiomyocyte apoptosis as evidenced by decreased TUNEL-positive cells and preserved mitochondrial membrane potential (MMP). Apelin decreased Bax/Bcl-2 ratio and limited the release of cytochrome C and activation of caspase-9 and caspase-3 both in vivo and in vitro. Finally, Apelin diminished the infarct size and normalized the impaired cardiac function as indicated by rescuing of the decreased ejection faction and fractional shortening in MI mice. In conclusion, Apelin prevented mitochondrial fission by inhibiting p-Drp1^Ser616, which prevents loss of MMP and inhibits the mitochondria-mediated apoptosis. These results indicate that the inhibition of Drp-1 activation by Apelin is a novel mechanism of cardioprotection against MI injury.