Ventricular arrhythmia is a fatal disease, typical drugs may benefit patients, but its side effects such as respiratory diseases, liver and kidney damage as well as bradyarrhythmia can never be ignored. Fortunately, long-time clinical work was told that DFD is an effective herb mixture to against antiarrhythmic. Since its excellent clinical efficacy, we conducted a Real-World Trial to assess the safety and efficacy of DFD for ventricular arrhythmia and the results demonstrate that DFD combined with metoprolol has better efficacy and safety than placebo combined with metoprolol. Besides, we explored the cellular electrophysiological mechanism of DFD, and DFD indeed has anti-arrhythmic effects based on its antioxidant potential, alleviation of Na+-K+-ATPase and connexin-43, and class I antiarrhythmic properties by suppressing Nav1.5dose-dependently with an IC50 of 24.0 ± 2.4 mg/mL. In this study, the bioactive components and underlying mechanisms of DFD in the treatment of VA were analyzed systematically.
Through related information collection and primary screening, we identified 28 potential targets of DFD in the treatment of VA. A PPI network was constructed with STRING and Cytoscape 3.8.0, the top 10 degree value genes were selected as hub gene and 3 function modules were divided based on its interactions. Analyzed all potential genes with VarElect, all 10 hub genes are directly related to the treatment of VA, and among these genes, KCNH2, TNNT2, CALM1 as well as SCN5A has the highest value of scores, in other words, these are the 4 genes with the highest correlation with the VA. Recently, KCNH2 could be a hot gene in the study of ventricular arrhythmia, it could mediate the rapidly activating component of the delayed rectifying potassium current in heart. A research suggested that pathogenic variants in KCNH2 encoding may result in Long QT syndrome47. Meanwhile, another research based on quantitative analysis of consortium disease cohorts and population controls pointed out among patients with long QT syndrome, the mutation probability of KCNH2 gene is greater than 85%48. Besides, another research mentioned the co-expression of CACNA1C and KCNH2 reduces the arrhythmic events49. TNNT2 is another hub gene connected to arrhythmias, a genetic analysis suggested that TNNT2 was co-segregated in ventricular arrhythmias and sudden death50. Wu launched a study based on zebrafish embryos, the result shows that zebrafish embryos exposed to procymidone are more likely alter transcription levels of TNNT2, and resulted in arrhythmia as well as increased heart rate finally51. Raffaele Coppini conducted a cohort study of patients with hypertrophic cardiomyopathy(HCM), the outcome indicated that among patients with HCM, most patients have a mutation in gene TNNT2, and these patients are more likely to Suffer from arrhythmias and HCM in the future52. SCN5A plays a vitally important role in the cardiac electrical conduction and arrhythmic risk, a study provided a new effective therapy to reduce arrhythmia through downregulating the expression of SCN5A53. Coincidentally, there is a study reported that a combination of quinidine/mexiletine reduces arrhythmia in patients with SCN5A gene mutation54. CALM1 is a regulator of voltage-dependent L-type calcium channels, its mutations are related to congenital arrhythmia55. Heterozygosity for the CALM1 mutation is causative of an arrhythmia syndrome56. Moreover, it can lead cathecolaminergic polymorphic ventricular tachycardia, idiopathic ventricular fibrillation, long QT syndrome, and even Sudden death57.
In the further GO and KEGG analysis, the results elucidated that the regulation of systemic arterial blood pressure by norepinephrone-epinephine, muslecontrction, blood circulation, circulatory system process, adrenergicreceptor activity, calcium signaling pathway, adenylate signaling in cardiomyocytes, cGMP-PKG signaling pathway and Neuroactive ligand-receptor interaction could be the most possible ways DFD works. Here, the regulation of calcium signaling pathway is affected by more hub genes than other pathways. According to a study based on the genomic, transcriptomic, and proteomic data initiated by Dan E Arking, calcium signaling pathway plays an important role both in the depolarization and repolarization of myocardial, particularly in the repolarization, during the plateau phase of the cardiac action potential, prolonged inward Ca2+ current leads to delays in ventricular myocyte repolarization58. Earlier research mentioned that Ca2+ waves can result when the Ca2+ ion influx into the cell is increased, and Ca2+ waves can generate depolarizations that trigger arrhythmias, It is reasonable to speculate that treatments related to calcium signaling pathways may be effective for arrhythmia59. Reports also suggested that the adrenergic signaling can increase the transmural difference between Ca2+ ion transients duration and action potential duration, finally, promoting the formation of delayed afterdepolarizations, the regulation of adenylate cyclase-activating adrenergic receptor signaling pathway and adrenergic receptor signaling pathway of DFD for VA may work in this way60. Adenylate cyclase-modulating G protein-coupled receptor signaling pathway can result in the regulation of G protein-mediated signaling, which is of great importance for the regulation of heart rate and involved in arrhythmias61. Besides, as we mentioned above, the potential targets were divided into 3 function modules, as shown in Table 3, it is obvious that the enrich analysis results of module 1 can regulate calcium signaling pathway, heart rate as well as cAMP signaling pathway, and it is to say that module 1 has great potential in the anti-arrhythmia. Module 2 can membrane depolarization during action potential, striated muscle contraction, regulate adrenergic signaling in cardiomyocytes and cation homeostasis, enrichment analysis shows that module 2 also has the possibility of anti-arrhythmia. The enrichment analysis of module 3 may not seem ideal, be careful, and we found 4 genes which connected to VA closest are gathered in function module 3, and it is reasonable to believe module 3 has anti-arrhythmic effects. Furthermore, as is shown in Fig. 5, the mutil-regulation in different aspects may benefit patients suffering from related diseases such as hypertension, cancer, and other diseases.
There are still some limitations in our research, although we tried to find out all components, such as Osdraconis (Fossiliaossiamastodi) (Longgu) and Ostrea Gigas Thunberg (Muli), the shell, mineral drugs, has only several pieces of research, with several components, and excluded for its low possibility and DL, but Osdraconis (Fossiliaossiamastodi) and Ostrea Gigas Thunberg (Muli) played important roles in DFD, according to the theoretical system of traditional Chinese medicine, both Osdraconis (Fossiliaossiamastodi) and Ostrea Gigas Thunberg can tranquilize mind, further studies are needed to confirm the sedative mechanism of Osdraconis (Fossiliaossiamastodi) and Ostrea Gigas Thunberg. Besides, so many components boiled together, researches are needed to determine whether there are some new compounds formed.