Analysis of Resibufogenin on Cardiac conduction reveals a species difference in the cardiac electrophysiology: Rats versus guinea pigs

Pharmacological insights and role of bufalin (bufadienolides) in inflammation modulation: a narrative review

Bufadienolides, specifically bufalin, have garnered attention for their potential therapeutic application in modulating inflammatory pathways. Bufalin is derived from toad venom and exhibits promising anti-inflammatory properties. Its anti-inflammatory effects have been demonstrated by influencing crucial signaling pathways like NF-B, MAPK, and JAK-STAT, resulting in the inhibition of pro-inflammatory substances like cytokines, chemokines, and adhesion molecules. Bufalin blocks inflammasome activation and reduces oxidative stress, hence increasing its anti-inflammatory properties. Bufalin has shown effectiveness in reducing inflammation-related diseases such as cancer, cardiovascular problems, and autoimmune ailments in preclinical investigations. Furthermore, producing new approaches of medication delivery and combining therapies with bufalin shows potential for improving its effectiveness and reducing adverse effects. This review explores the pharmacological effects and mechanistic approaches of bufalin as an anti-inflammatory agent, which further highlights its potential for therapy and offers the basis for further study on its therapeutic application in inflammation-related disorders.

The application and mechanism of Chinese medicine in the upstream treatment of atrial fibrillation

Upstream treatment of atrial fibrillation (AF, for short) is a new approach to the prevention and treatment of AF with non-antiarrhythmic drugs, which is essentially primary and secondary prevention of AF. The former refers to the prevention of AF by controlling risk factors such as diabetes, hypertension, and heart failure before AF occurs, and the latter mainly refers to targeting ion channels, inflammation, oxidative stress, and other pathways to reduce or reverse atrial electrical and structural remodeling, reduction of AF load, and reduction of the chance of AF occurrence or progression. More and more studies have shown that many traditional Chinese medicines, active ingredients of Chinese medicines, and Chinese herbal formulas have definite effects on the upstream treatment of AF, but their mechanisms of action are different. Therefore, we summarized the relevant literature on the application and mechanisms of Chinese medicine on the upstream treatment of AF in recent years, hoping to be helpful for subsequent studies.

Sophoridine manifests as a leading compound for anti-arrhythmia with multiple ion-channel blocking effects

BACKGROUND

Sophoridine (SR) has shown the potential to be an antiarrhythmic agent. However, SR's electrophysiological properties and druggability research are relatively inadequate, which limits the development of SR as an antiarrhythmic candidate.

PURPOSE

To facilitate the development process of SR as an antiarrhythmic candidate, we performed integrated studies on the electrophysiological properties of SR in vitro and ex vivo to gain more comprehensive insights into the multi-ion channel blocking effects of SR, which provided the foundation for the further drugability studies in antiarrhythmic and safety studies. Firstly, SR's electrophysiological properties and antiarrhythmic potentials were recorded and assessed at the cell and tissue levels by comprehensively integrating the patch clamp with the Electrical and Optical Mapping systems. Subsequently, the antiarrhythmic effects of SR were validated by aconitine and ouabain-induced arrhythmia in vivo. Finally, the safety of SR as an antiarrhythmic candidate compound was evaluated based on the guidelines of the Comprehensive in Vitro Proarrhythmia Assay (CiPA).

STUDY DESIGN

The antiarrhythmic effect of SR was evaluated at the in vitro, ex vivo, and in vivo levels.

METHODS

Isolated primary cardiomyocytes and stable cell lines were prepared to explore the electrophysiologic properties of being a multiple ion-channel blocker in vitro by whole-cell patch clamp. Using electrical and optical mapping, the negative chronotropic effect of SR was determined in langendorff-perfused rat or guinea-pig hearts.The antiarrhythmic activity of SR was assessed by the ex vivo tachyarrhythmia models induced by left coronary artery ligation (LCAL) and isoproterenol (ISO). Canonical models of aconitine and ouabain-induced arrhythmia were used to verify the antiarrhythmic effects in vivo. Finally, the pro-arrhythmic risk of SR was detected in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes (hSCCMs) using a Microelectrode array (MEA).

RESULTS

Single-cell patch assay validated the multiple ion-channel blockers of SR in transient outward current potassium currents (Ito), l-type calcium currents (ICa-l), and rapid activation delayed rectifier potassium currents (IKr). SR ex vivo depressed heart rates (HR) and ventricular conduction velocity (CV) and prolonged Q-T intervals in a concentration-dependent manner. Consistent with the changes in HRs, SR extended the active time of hearts and increased the action potential duration measured at 90% repolarization (APD90). SR could also significantly lengthen the onset time and curtail the duration of spontaneous ventricular tachycardia (VT) in the ex vivo arrhythmic model induced by LCAL. Meanwhile, SR could also significantly upregulate the programmed electrical stimulation (PES) frequency after the ISO challenge in forming electrical alternans and re-entrant excitation. Furthermore, SR exerted antiarrhythmic effects in the tachyarrhythmia models induced by aconitine and ouabain in vivo. Notably, the pro-arrhythmic risk of SR was shallow for a moderate inhibition of the human ether-à-go-go-related gene (hERG) channel. Moreover, SR prolonged field potential duration (FPDc) of hSCCMs in a concentration-dependent manner without early after depolarization (EAD) and arrhythmia occurrence.

CONCLUSION

Our results indicated that SR manifested as a multiple ion-channel blocker in the electrophysiological properties and exerts antiarrhythmic effects ex vivo and in vivo. Meanwhile, due to the low pro-arrhythmic risk in the hERG inhibition assay and the induction of EAD, SR has great potential as a leading candidate in the treatment of ventricular tachyarrhythmia.

Novel Strategies for Solubility and Bioavailability Enhancement of Bufadienolides

Toad venom contains a large number of bufadienolides, which have a variety of pharmacological activities, including antitumor, cardiovascular, anti-inflammatory, analgesic and immunomodulatory effects. The strong antitumor effect of bufadienolides has attracted considerable attention in recent years, but the clinical application of bufadienolides is limited due to their low solubility and poor bioavailability. In order to overcome these shortcomings, many strategies have been explored, such as structural modification, solid dispersion, cyclodextrin inclusion, microemulsion and nanodrug delivery systems, etc. In this review, we have tried to summarize the pharmacological activities and structure-activity relationship of bufadienolides. Furthermore, the strategies for solubility and bioavailability enhancement of bufadienolides also are discussed. This review can provide a basis for further study on bufadienolides.