Adenosine signaling as target in cardiovascular pharmacology

Study on the Molecular Mechanism of XiaoXianXiong Decoction in the Treatment of Atherosclerosis Based on UHPLC-Q Exactive Focus MS/MS, Network Pharmacology, and Experimental Validation

Atherosclerosis (AS), a leading pathological basis of severe cardiovascular diseases, poses a significant threat to human health. XiaoXianXiong Decoction (XXXD), a classical traditional Chinese medicine (TCM) prescription, has demonstrated promising effects in the treatment of AS. To investigate the underlying mechanism of XXXD in treatment with AS, we used UHPLC-Q Focus MS/MS, network pharmacology and in vivo validation methods. The results showed that 59 chemical components of XXXD were identified. Network pharmacology showed that 11 key compounds, 10 key targets and five key signaling pathways involved in the therapeutic effects of XXXD on AS. Experimental verification confirmed that XXXD significantly improved dyslipidemia, lipid accumulation and pathological changes in the aorta during AS. These effects were linked to the inhibition of the PI3K/AKT signaling pathway, down-regulation of PI3K, HRAS, EGF, CREB and up-regulation of NOS3 expression. This work may provide a theoretical basis for further research on the molecular mechanisms for XXXD in AS treatment.

Distribution and Pharmacokinetic Characteristics of Cordycepin in Rat: Investigated by UHPLC-HRMS/MS and Blood-Brain Synchronous Microdialysis

Cordycepin, a natural adenosine derivative, exhibits multiple pharmacological effects on organisms. However, its distribution and metabolic characteristics have not been fully elucidated in vivo. In this study, ultra-high liquid chromatography tandem high-resolution mass spectrometry (UHPLC-HRMS/MS) was used to investigate the pharmacokinetic characteristics and effects of cordycepin on endogenous adenosine and inosine. Microdialysis was used for real-time monitoring of unbound drug in brain and blood, whereas conventional tissue homogenate methods assessed distribution in various tissues. Results showed that the distribution pattern of cordycepin was as follows: kidney > liver > heart > lung > spleen > brain. Cordycepin administration significantly altered the levels of adenosine and inosine in heart and liver. Synchronous microdialysis sampling for the pharmacokinetic profile indicated that cordycepin was rapidly consumed and 3'-deoxyinosine was generated as the main metabolite. The Cmax values of cordycepin in the rat blood and brain after exposure (10 mg/kg, i.p.) were 7.8 and 5.4 ng/mL, respectively. Mean residence time in blood and brain was 102.2 and 137.0 min, respectively. Inhibition of adenosine deaminase by racemic 9-(2-hydroxy-3-nonyl) adenine hydrochloride (EHNA) enhanced cordycepin levels in the blood. This work provides a solid basis for understanding the metabolism of cordycepin and its pharmacological effects.

Role of A1 adenosine receptor in cardiovascular diseases: Bridging molecular mechanisms with therapeutic opportunities

Adenosine serves as a critical homeostatic regulator, exerting influence over physiological and pathological conditions in the cardiovascular system. During cellular stress, increased extracellular adenosine levels have been implicated in conferring cardioprotective effects through the activation of adenosine receptors with the A1 adenosine receptor subtype showing the highest expression in the heart. A1 adenosine receptor stimulation inhibits adenylyl cyclase activity via heterotrimeric Gi proteins, leading to the activation of distinct downstream effectors involved in cardiovascular homeostasis. While the comprehensive characterization of the pharmacological functions and intracellular signaling pathways associated with the A1 adenosine receptor subtype is still ongoing, this receptor is widely recognized as a crucial pharmacological target for the treatment of various states of cardiovascular diseases (CVDs). In this review, we focus on elucidating signal transduction of A1 adenosine receptor, particularly Gi protein-dependent and -independent pathways, and their relevance to cardiovascular protective effects as well as pathological consequences during cellular and tissue stresses in the cardiovascular system. Additionally, we provide comprehensive updates and detailed insights into a range of A1 adenosine receptor agonists and antagonists, detailing their development and evaluation through preclinical and clinical studies with a specific focus on their potential for the management of CVDs, especially heart diseases.

Electrophysiological and sick sinus syndrome effects of Remdesivir challenge in guinea-pig hearts

Remdesivir (RDV) is the first drug approved by the FDA for clinical treatment of hospitalized patients infected with COVID-19 because it has been shown to have good antiviral activity against a variety of viruses, including Arenaviridae and Coronaviridae viral families. However, it has been reported that its clinical treatment leads to the symptoms of sick sinus syndrome such as sinus bradycardia, conduction block, and sinus arrest, but the electrophysiological mechanism of its specific cardiac adverse events is still unclear. We report complementary, experimental, studies of its electrophysiological effects. In wireless cardiac telemetry experiments in vivo and electrocardiographic studies in ex vivo cardiac preparations, RDV significantly caused sinus bradycardia, sinus atrial block, and prolongation of the QT interval in guinea pigs. Dose-dependent effects of RDV on the electrical activities of sinoatrial node (SA node) preparations of guinea pigs were characterised by multielectrode, optical RH237 voltage mapping. These revealed reversibly reduced sinoatrial conduction time (SACT), increased AP durations (APDs), and decreased the pacemaking rate of the SA node. Patch-clamp experiments showed that RDV significantly inhibited the If current of HCN4 channels, resulting in a significant decrease in the spontaneous firing rate of SA node cells, which may underlie the development of sick sinus node syndrome. In addition, RDV significantly inhibits IKr currents in hERG channels, leading to prolongation of the QT interval and playing a role in bradycardia. Therefore, these findings provide insights into the understanding the bradycardia effect of RDV, which may be used as basic theoretical guidance for the intervention of its adverse events, and prompt safety investigations of RDV's cardiac safety in the future.

Overview of multifunctional Tregs in cardiovascular disease: From insights into cellular functions to clinical implications

Regulatory T cells (Tregs) are crucial in regulating T-cell-mediated immune responses. Numerous studies have shown that dysfunction or decreased numbers of Tregs may be involved in inflammatory cardiovascular diseases (CVDs) such as atherosclerosis, hypertension, myocardial infarction, myocarditis, cardiomyopathy, valvular heart diseases, heart failure, and abdominal aortic aneurysm. Tregs can help to ameliorate CVDs by suppressing excessive inflammation through various mechanisms, including inhibition of T cells and B cells, inhibition of macrophage-induced inflammation, inhibition of dendritic cells and foam cell formation, and induction of anti-inflammatory macrophages. Enhancing or restoring the immunosuppressive activity of Tregs may thus serve as a fundamental immunotherapy to treat hypertension and CVDs. However, the precise molecular mechanisms underlying the Tregs-induced protection against hypertension and CVDs remain to be investigated. This review focuses on recent advances in our understanding of Tregs subsets and function in CVDs. In addition, we discuss promising strategies for using Tregs through various pharmacological approaches to treat hypertension and CVDs.

Combined modified Valsalva maneuver with adenosine supraventricular tachycardia: A comparative study

BACKGROUND AND IMPORTANCE

Paroxysmal supraventricular tachycardia (PSVT) is an arrhythmia commonly seen in the emergency department. Both modified Valsalva maneuver (MVM) and intravenous adenosine are the first line treatment, of which the former has e lower success rate while the latter has a higher success rate but some risks and adverse effects. Given both of these reverse rhythms quickly, combining them may achieve a better effect.

OBJECTIVE

The objective of this study is to evaluate the success rate and potential risk of combining the use of intravenous adenosine while patients were doing MVM as a treatment for paroxysmal supraventricular tachycardia(pSVT).

DESIGN, SETTINGS AND PARTICIPANTS

We recruited patients with pSVT from 2017 to 2022, and randomly assigned them into 3 groups, MVM group, intravenous adenosine group, and combination therapy group, in which MVM was allowed to be performed twice, while intravenous adenosine was given in a titration manner to repeat three times, recorded the success rate and side effects in each group.

MAIN RESULTS

The success rate of the MVM group, adenosine group, and combination group are 42.11%, 75.00 and 86.11%, respectively. The success rate of the adenosine group and combination group is significantly higher than the n MVSM group (p < 0.01, p < 0.001), while the success rate of the combination group is higher than the adenosine group, it has no significant difference (p = 0.340). In terms of safety, the longest RR durations (asystole period) are 1.61 s, 1.60s, and 2.27 s, there is a statistical difference among the three groups (p < 0.01) and between the adenosine and combination group (0.018).

CONCLUSION

Therefore, we can conclude that combination therapy has a relatively high success rate and good safety profile, but the current study failed to show its superiority to adenosine.