Angiotensin II and angiotensin 1-7: which is their role in atrial fibrillation?

Circ_0079480 facilitates proliferation, migration and fibrosis of atrial fibroblasts in atrial fibrillation by sponing miR-338-3p to activate the THBS1/TGF-β1/Smad3 signaling

BACKGROUND

Atrial fibrosis is associated with the pathogenesis of atrial fibrillation (AF). This study aims to discuss the function of circ_0079480 in atrial fibrosis and its underlying mechanism.

METHODS

In vitro and in vivo models of atrial fibrosis were established by using angiotensin II (Ang II) to treat human atrial fibroblasts (HAFs) and C57/B6J mice. qRT-PCR and western blot were used to examine the mRNA and protein expression levels. CCK-8, EdU, cell strach, and transwell assays were performed to determine the proliferation and migration of HAFs. Dual-luciferase reporter and RIP/RNA pull-down assays were explored to identify the interaction of miR-338-3p and circ_0079480/THBS1. HE and Masson's trichrome staining experiments were performed to analyze the histopathological change in mice atrial tissues.

RESULTS

Circ_0079480 expression was increased in AF patients' atrial tissues and Ang II-treated HAFs. Silencing circ_0079480 inhibited cell proliferation and migration and reduced fibrosis-associated gene expression in Ang II-treated HAFs. Circ_0079480 could target miR-338-3p to repress its expression. MiR-338-3p inhibitor blocked the inhibitory effects of circ_0079480 knockdown on HAFs proliferation, migration, and fibrosis. Thrombospondin-1 (THBS1) was confirmed as a downstream target of miR-338-3p, and circ_0079480 could sponge miR-338-3p to upregulate THBS1 expression. Moreover, silencing THBS1 suppressed Ang II-induced proliferation, migration, and fibrosis in HAFs. More importantly, depletion of circ_0079480 inactivated the THBS1/TGF-β1/Smad3 signaling by upregulating miR-338-3p. Mice experiments also confirmed the suppression of circ_0079480 knockdown on atrial fibrosis.

CONCLUSION

Circ_0079480 acts as a sponge of miR-338-3p to upregulate THBS1 expression and activate the TGF-β1/Smad3 signaling, finally promoting Ang II-induced atrial fibrosis.

Effects of sacubitril-valsartan on aging-related cardiac dysfunction

Heart failure (HF) remains a huge medical burden worldwide, with aging representing a major risk factor. Here, we report the effects of sacubitril/valsartan, an approved drug for HF with reduced EF, in an experimental model of aging-related HF with preserved ejection fraction (HFpEF). Eighteen-month-old female Fisher 344 rats were treated for 12 weeks with sacubitril/valsartan (60 mg/kg/day) or with valsartan (30 mg/kg/day). Three-month-old rats were used as control. No differential action of sacubitril/valsartan versus valsartan alone, either positive or negative, was observed. The positive effects of both sacubitril/valsartan and valsartan on cardiac hypertrophy was evidenced by a significant reduction of wall thickness and myocyte cross-sectional area. Contrarily, myocardial fibrosis in aging heart was not reduced by any treatment. Doppler echocardiography and left ventricular catheterization evidenced diastolic dysfunction in untreated and treated old rats. In aging rats, both classical and non-classical renin-angiotensin-aldosterone system (RAAS) were modulated. In particular, with respect to untreated animals, both sacubitril/valsartan and valsartan showed a partial restoration of cardioprotective non-classical RAAS. In conclusion, this study evidenced the favorable effects, by both treatments, on age-related cardiac hypertrophy. The attenuation of cardiomyocyte size and hypertrophic response may be linked to a shift towards cardioprotective RAAS signaling. However, diastolic dysfunction and cardiac fibrosis persisted despite of treatment and were accompanied by myocardial inflammation, endothelial activation, and oxidative stress.

Pathophysiological Mechanisms of Psychosis-Induced Atrial Fibrillation: The Links between Mental Disorder and Arrhythmia

Atrial fibrillation (AF) is a common phenomenon of sustained arrhythmia leading to heart failure or stroke. Patients with mental disorders (MD), particularly schizophrenia and bipolar disorder, are at a high risk of AF triggered by the dysregulation of the autonomic nervous system, atrial stretch, oxidative stress, inflammation, and electrical or structural remodeling. Moreover, pathophysiological mechanisms underlying MD may also contribute to the genesis of AF. An overactivated hypothalamic-pituitary-adrenal axis, aberrant renin-angiotensin-aldosterone system, abnormal serotonin signaling, disturbed sleep, and genetic/epigenetic factors can adversely alter atrial electrophysiology and structural substrates, leading to the development of AF. In this review, we provide an update of our collective knowledge of the pathophysiological and molecular mechanisms that link MD and AF. Targeting the pathogenic mechanisms of MD-specific AF may facilitate the development of therapeutics that mitigate AF and cardiovascular mortality in this patient population.

The causality of atrial fibrillation on frailty index: A Mendelian randomization study

Prior epidemiological research has indicated a possible association between atrial fibrillation (AF) and frailty status. Our study used Mendelian randomization to estimate its causality. The genome-wide association studies for AF were utilized as the exposure for individuals included in the UK Biobank (n = 463,010) and publicly available summary statistics data sets of genome-wide association studies meta-analyses for frailty index in individuals of European descent (n = 175,226) was used as the outcome. The inverse variance weighting method was utilized to evaluate causality. To further confirm the reliability of the results, sensitivity analyses were conducted. The inverse variance weighting analysis indicated that the presence of AF was found to be statistically linked to an increased risk of frailty (odds ratio = 3.017, CI: 1.106-8.232, P = .031). MR-Egger intercept test indicated no pleiotropy (Egger intercept = .002, P = .808). The leave-one-out method indicated that the individual SNPs did not have an impact on the robustness of the findings. The research implies a causal relationship between AF and frailty. Early detection and timely intervention of AF can control the occurrence of frailty.

Small Left Ventricle in Patients With Atrial Fibrillation Is Associated With Increased Cardiovascular Risk

BACKGROUND

It is still unclear whether small left ventricle (LV) is an adverse structural prognostic feature in patients with atrial fibrillation (AF).

OBJECTIVES

The purpose of this study was to evaluate the association between small LV and risk of cardiovascular events in AF population.

METHODS

From the China-AF registry, 7,764 patients with AF were enrolled and divided into groups with normal, small, and large LV size based on left ventricular end-diastolic dimension (LVEDD) measurement per the American Society of Echocardiography references. Cox models were used to assess the association between LV size or LVEDD with composite cardiovascular events (cardiovascular death, ischemic stroke or systemic embolism, or major bleeding).

RESULTS

There were 308 (4.0%) participants assessed with small LV who were older, with lower body mass and blood pressure, and fewer comorbidities, and 429 (5.5%) were identified with large LV. Compared with the normal LV group, small LV and large LV were significantly associated with higher incidence of composite cardiovascular events (adjusted HR [aHR]: 1.54 [95% CI: 1.07-2.20] for small LV; aHR: 1.36 [95% CI: 1.02-1.81] for large LV) and cardiovascular death (aHR: 1.94 [95% CI: 1.14-3.28] for small LV; aHR: 1.83 [95% CI: 1.24-2.69] for large LV). Small LV was also associated with increased risk of major bleeding [aHR: 2.21 [95% CI: 1.01-4.86]). A U-shaped relationship between LVEDD and composite cardiovascular events was identified (Pnonlinear < 0.001).

CONCLUSIONS

In a prospective AF cohort, small LV was independently associated with an increased risk of cardiovascular events, which needed consideration in risk stratification and management for patients with AF. (ChiCTR-OCH-13003729).

Cardiovascular medications used for comorbid diseases in patients with atrial fibrillation. The JoFib study

PURPOSE

Many atrial fibrillation (AF) patients use cardiovascular medications for indications other than AF. These medications can affect morbidity and mortality. We aim to investigate the characteristics of AF patients who use different medication classes and their clinical course.

METHODS

We collected data from the prospective, multicenter registry, JoFib study. We identified classes of non-AF medications (medications not used for rate control, rhythm control, or anticoagulation), described demographic and clinical characteristics, and investigated AF-related outcomes according to these medication classes.

RESULTS

From a total of 2020 patients, five classes of cardiovascular non-AF medications were identified, aspirin, P2Y12 inhibitors, ACE inhibitors/ARBs, statins, and diuretics. The most commonly used non-AF medications were diuretics and ACE inhibitors/ARBs (39.2%, and 39%, respectively). 51% of AF patients took more than one non-AF medication. Multivariable Cox regression analysis demonstrated that ACE inhibitor/ARB therapy independently reduced the risks of all-cause mortality and cardiovascular mortality (aHR 0.50, 95%CI 0.37-0.68; aHR 0.51, 95%CI 0.34-0.75, respectively) and that statin therapy reduced the risk of cardiovascular mortality (aHR 0.68, 95%CI 0.48-0.98) in AF patients. Multivariable logistic regression analysis demonstrated a protective effect of statin therapy against the secondary outcome, clinically relevant non-major bleeding (CRNMB) (adjusted OR 0.62 95%CI 0.42-0.94).

CONCLUSION

Our findings suggest a protective effect of ACE inhibitors/ARBs against all-cause and cardiovascular mortality, statins against cardiovascular mortality, and CRNMB in patients with AF. Accordingly, these medications should be encouraged in patients with AF when indicated. Additionally, future research should explore whether these medications should be offered to AF patients more routinely. The study was registered with Clinicaltrials.gov (unique identifier number: NCT03917992, Registration date:14/4/2019).

Overreactive macrophages in SARS-CoV-2 infection: The effects of ACEI

Among various factors influencing the course of SARS-CoV-2 infection in humans, macrophage overactivation is considered the main cause of the cytokine storm that leads to severe complications of COVID-19. Moreover, the increased expression of angiotensin converting enzyme 2 (ACE2), an obligatory entry receptor of the coronavirus, caused by treatment with ACE inhibitors (ACEI) lowered overall confidence in the safety of these drugs. However, analysis of the course of coronavirus infection in patients treated with ACEI does not support these concerns. Instead, the beneficial effect of ACEI on macrophages has increasingly been emphasized. This includes their anti-inflammatory activation and the consequent reduction in the risk of severe disease and life-threatening complications. Herein, we summarize the current knowledge and understanding of the dual role of macrophages in SARS-CoV-2 infection, with a special focus on the postulated mechanisms underlying the beneficial effects of macrophage targeting by ACEI. These seem to involve the stimulation of macrophage angiotensin II type 2 and Mas receptors by angiotensin 1-7, intensively produced due to the up-regulation of ACE2 expression on macrophages, as well as the direct inhibition of macrophage hyper-responsiveness by ACEI. The impact of ACEI on macrophages may also lead to the activation of an effective antiviral response due to the increased expression of ACE2.

DNA Methylation and Telomeres-Their Impact on the Occurrence of Atrial Fibrillation during Cardiac Aging

Atrial fibrillation (AF) is the most common arrhythmia in humans. AF is characterized by irregular and increased atrial muscle activation. This high-frequency activation obliterates the synchronous work of the atria and ventricles, reducing myocardial performance, which can lead to severe heart failure or stroke. The risk of developing atrial fibrillation depends largely on the patient's history. Cardiovascular diseases are considered aging-related pathologies; therefore, deciphering the role of telomeres and DNA methylation (mDNA), two hallmarks of aging, is likely to contribute to a better understanding and prophylaxis of AF. In honor of Prof. Elizabeth Blackburn's 75th birthday, we dedicate this review to the discovery of telomeres and her contribution to research on aging.

The neutrophil-to-lymphocyte ratio is a potential biomarker for the occurrence of atrial fibrillation in patients with obstructive sleep apnea: A BIOMARKER OF AF IN OSA PATIENTS

BACKGROUND

Obstructive sleep apnea (OSA) affects the occurrence of atrial fibrillation (AF) and usually coexists with AF. Chronic inflammation has been identified as an important factor in the development of AF, and the neutrophil-to-lymphocyte ratio (NLR) has been identified as a biomarker that positively correlates with the degree of inflammation. However, little information regarding how NLR correlates with AF in OSA patients.

METHODS

Our study enrolled 368 patients with OSA between September 2018 and April 2023. All data were collected after admission. Independently associated factors were assessed by multivariate logistic regression and then constructed a nomogram to predict AF risk. Nomogram's calculation model was evaluated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). The correlation between CHA2DS2-VASc scores and NLR was assessed using Spearman correlation.

RESULTS

Multivariate logistic regression showed that high level log-transformed NLR (OR, 1.664; 95% CI, 1.026-2.699; P = 0.039) was independently associated with the presence of AF in patients with OSA. The concordance index (0.817, 95% CI, 0.770-0.864), ROC curve, calibration curve, and DCA of the nomogram indicated this model had well clinical utility. Also, the nomogram's calculation model could identify patients who are at a higher risk of developing AF, and the CHA2DS2-VASc score was positively correlated with NLR in patients with AF (P < 0.05).

CONCLUSION

The elevated NLR may serve as a promising biomarker for assessing the risk of AF in individuals with OSA. The nomogram's calculation model may be utilized as a tool to estimate the probability of AF occurrence in OSA patients.

Recent Advances in Antiarrhythmic Drug Therapy

Cardiac arrhythmias remain a common cause of death and disability. Antiarrhythmic drugs (AADs) and antiarrhythmic agents remain a cornerstone of current cardiac arrhythmia management, despite moderate efficacy and the potential for significant adverse proarrhythmic effects. Due to conceptual, regulatory and financial considerations, the number of novel antiarrhythmic targets and agents in the development pipeline has decreased substantially during the last few decades. However, several promising candidates remain and there are exciting developments in repurposing and reformulating already existing drugs for indications related to cardiac arrhythmias. This review discusses the key conceptual considerations for the development of new antiarrhythmic agents, summarizes new compounds and formulations currently in clinical development for rhythm control of atrial fibrillation, and highlights the potential for drug repurposing. Finally, future directions in AAD development are discussed. Together with an ever-increasing understanding of the molecular mechanisms underlying cardiac arrhythmias, these components support a cautiously optimistic outlook towards improved pharmacological treatment opportunities for patients suffering from cardiac arrhythmias.

Effects of ACEI/ARB or CCB use on atrial fibrillation in hypertensive patients following permanent pacemaker implantation

Aims

Permanent pacemaker implantation (PPI) combined with hypertension leads to a higher risk of new-onset atrial fibrillation (NOAF) for patients. Hence, it is essential to study how to reduce this risk. Currently, the effects of the two common anti-hypertensive drugs, angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) and calcium channel blockers (CCB), on the risk of NOAF for such patients remain unknown. This study aimed to investigate this association.

Methods

This single-center retrospective study included hypertensive patients with PPI and without prior history of AF/atrial flutter, heart valve disease, hyperthyroidism, etc. Patients were classified into ACEI/ARB group and CCB group based on their exposure drug information. The primary outcome was NOAF events that occurred within 12 months after PPI. The secondary efficacy assessments were the changes from baseline to follow-up in blood pressure and transthoracic echocardiography (TTE) parameters. A multivariate logistic regression model was used to verify our aim.

Results

A total of 69 patients were finally included (51 on ACEI/ARB and 18 on CCB). Both univariate analysis [odds ratio (OR) 0.241, 95% confidence interval (CI) 0.078-0.745] and multivariate analysis (OR: 0.246, 95% CI: 0.077-0.792) demonstrated that ACEI/ARB were associated with a lower risk of NOAF compared to CCB. The mean reduction in left atrial diameter (LAD) from baseline was greater in ACEI/ARB group than in CCB group (P = 0.034). There was no statistical difference between groups in blood pressure and other TTE parameters after treatment.

Conclusion

For patients with PPI combined with hypertension, ACEI/ARB may be superior to CCB in selecting anti-hypertensive drugs, as ACEI/ARB further reduces the risk of NOAF. One reason for this may be that ACEI/ARB improves left atrial remodelling such as LAD better.

COVID-19 Vaccines and Atrial Fibrillation: Analysis of the Post-Marketing Pharmacovigilance European Database

Atrial fibrillation (AF) has been described in COVID-19 patients. Recently, some case reports and US pharmacovigilance analyses described AF onset as a rare adverse event following COVID-19 vaccination. The possible correlation is unclear. We systematically analyzed the reports of AF related to COVID-19 vaccines collected in the European pharmacovigilance database, EudraVigilance (EV), from 2020 to November 2022. We carried out descriptive and disproportionality analyses. Moreover, we performed a sensitivity analysis, excluding the reports describing other possible alternative AF causes (pericarditis, myocarditis, COVID-19, or other drugs that may cause/exacerbate AF). Overall, we retrieved 6226 reports, which represented only 0.3% of all those related to COVID-19 vaccines collected in EV during our study period. AF reports mainly referred to adults (in particular, >65 years old), with an equal distribution in sex. Reports were mainly related to tozinameran (54.04%), elasomeran (28.3%), and ChAdOx1-S (14.32%). The reported AF required patient hospitalization in 35% of cases and resulted in a life-threatening condition in 10% of cases. The AF duration (when reported) was highly variable, but the majority of the events had a short duration (moda = 24 h). Although an increased frequency of AF reporting with mRNA vaccines emerges from our study, other investigations are required to investigate the possible correlation between COVID-19 vaccination and the rare AF occurrence.

The Association Between Rheumatoid Arthritis and Atrial Fibrillation: Epidemiology, Pathophysiology and Management

Atrial fibrillation (AF) is the most common cardiac arrhythmia with a significant increase in morbidity and mortality worldwide. Rheumatoid arthritis (RA), as a systemic inflammatory disease, affecting 0.5-1.0% of the adult population, is associated with increased incidence of cardiac arrhythmias such as AF. Several epidemiologic studies find that the risk of AF is increased in RA when compared with the general population. Other studies are inconsistent. Considering that inflammation plays an important role in AF, RA may be involved in the occurrence and development of AF. This review summarizes the epidemiology, pathophysiology, and management of AF in patients with RA.

Atrial fibrillation: Epigenetic aspects and role of sodium-glucose cotransporter 2 inhibitors

Atrial fibrillation (AF) is the most frequent arrhythmia and is associated with substantial morbidity and mortality. Pathophysiological aspects consist in the activation of pro-fibrotic signaling and Ca²⁺ handling abnormalities at atrial level. Structural and electrical remodeling creates a substrate for AF by triggering conduction abnormalities and cardiac arrhythmias. The care of AF patients focuses predominantly on anticoagulation, symptoms control and the management of risk factors and comorbidities. The goal of AF therapy points to restore sinus rhythm, re-establish atrioventricular synchrony and improve atrial contribution to the stroke volume. New layer of information to better comprehend AF pathophysiology, and identify targets for novel pharmacological interventions consists of the epigenetic phenomena including, among others, DNA methylation, histone modifications and noncoding RNAs. Moreover, the benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in diabetic and non-diabetic patients at cardiovascular risk as well as emerging evidence on the ability of SGLT2i to modify epigenetic signature in cardiovascular diseases provide a solid background to investigate a possible role of this drug class in the onset and progression of AF. In this review, following a summary of pathophysiology and management, epigenetic mechanisms in AF and the potential of sodium-glucose SGLT2i in AF patients are discussed.

Vaspin Attenuates Atrial Abnormalities by Promoting ULK1/FUNDC1-Mediated Mitophagy

The worldwide incidence and prevalence of atrial fibrillation (AF) are increasing, making it a life-threatening condition due to the higher numbers of people suffering from obesity. Vaspin, an adipokine derived from epicardial adipose tissue, has been reported to reduce inflammation, inhibit apoptosis, and induce autophagy; however, its role in the pathogenesis of AF is not known. In this study, we investigated the role of vaspin in patients with AF and explored the molecular mechanisms using atrial myocytes in vitro. Our data showed that vaspin levels were significantly reduced in the plasma of patients with AF. Lower plasma levels of vaspin were also associated with a higher risk of AF in patients with obesity. Vaspin treatment in vitro alleviated cardiomyocyte injury, atrial fibrosis, atrial myocyte apoptosis, and mitochondrial injury in atrial myocytes following Ang-II stress. Moreover, our results demonstrated that vaspin protected against Ang-II-induced atrial myocyte dysfunction by inducing mitophagy. We also observed that vaspin treatment enhanced the phosphorylation of Fun14 domain-containing protein 1 (FUNDC1) at Ser17 by unc-51 like autophagy activating kinase 1 (ULK1), resulting in the induction of mitophagy. These positive effects of vaspin were reversed by ULK1 silencing in Ang-II-stimulated HL-1 cells. Our study is the first to propose that vaspin plays a vital role in AF pathogenesis via ULK1/FUNDC1-regulated mitophagy and could be a novel therapeutic target for AF.

The Predictive Value of Epicardial Fat Tissue Volume in the Occurrence and Development of Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background

Atrial fibrillation (AF) is one of the most common arrhythmias in clinical practice. Although fat is currently considered to be a risk factor for AF and a pathogenic link between epicardial fat tissue (EFT) and AF has been speculated, there are currently few clinical studies and literature data domestically or abroad.

Objective

This study conducted a meta-analysis of observational case series studies to verify the relationship between atrial fibrillation and EFT and to strengthen the predictive value of EFT in the occurrence, development, and postablative recurrence of AF.

Methods

We conducted a systematic search of the literature in electronic databases until December 2021 and supplemented this through manual searches of individual studies, reviewed articles, and reference lists in conference proceedings. This study conducted a meta-analysis to compare the differences between different populations, such as healthy participants and AF patients, healthy subjects and AF subtype cases, and paroxysmal and persistent AF with AF recurrence and without AF recurrence after ablation.

Results

Following the retrieval of 828 articles, only 22 articles were selected as research results. Accordingly, the meta-analysis results show that the volume of EFT in AF is greater than that in healthy subjects (MD = 39.34 ml, 95% CI = 27.11, 51.58); persistent AF is greater than paroxysmal AF (MD = 14.37 ml, 95% CI = 7.46, 21.27); and recurrence after ablation is greater than without recurrence (MD = 14.37 ml, 95% CI = 7.46, 21.27).

Conclusion

The results of this study further confirm the connection between EFT and AF and that EFT has a certain predictive value for the occurrence and development of AF.

Circulating Galectin-3 and Aldosterone for Predicting Atrial Fibrillation Recurrence after Radiofrequency Catheter Ablation

Background

Circulating galectin-3 (Gal-3) and aldosterone (ALD) are involved in fibrosis and inflammation. However, their potential value as predictors of atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA) is unknown or controversial. Therefore, the aim of this study was to assess the relationship between baseline Gal-3, ALD levels, and AF recurrence in patients performing RFCA.

Methods

153 consecutive patients undergoing RFCA were included. Gal-3 and ALD were measured at baseline. Univariate and multivariate Cox regressions were performed to determine the predictors of AF recurrence. Receiver operating characteristic (ROC) curve and Kaplan-Meier (K-M) curve were used to assess the value of predictors.

Results

There were 35 (22.88%) cases of AF recurrence after RFCA. The recurrence group had significantly higher preoperative serum levels of Gal-3 and ALD than the nonrecurrence group. Univariate and multivariate analysis showed that Gal-3 (HR = 1.28, 95% CI: 1.04-1.56, p = 0.02) and ALD (OR = 1.02, 95% CI: 1.00-1.03, p < 0.03) were significantly associated with AF recurrence after RFCA. The area under the curve (AUC) of preoperative serum Gal-3, ALD, and 2 combined to predict the recurrence of AF patients after RFCA was 0.636, 0.798, and 0.893, respectively, while sensitivity was 65.32%, 71.69%, and 88.61%, respectively and specificity was 77.46%, 78.53%, and 86.0%, respectively. Patients with Gal-3 above the cutoff value of 14.57 pg/ml had higher frequent AF recurrence than the patients with Gal − 3 ≤ 14.57 pg/ml (35% vs. 12%, p < 0.001) during a follow-up. Meanwhile, patients with ALD above the cutoff value of 243.61 pg/ml also had a higher AF recurrence rate than those with ALD ≤ 243.61 pg/ml (37% vs. 11%, p < 0.001) during a follow-up. The recurrence rate in patients with Gal − 3 > 14.57 pg/ml + ALD > 243.61 pg/ml was higher than that in patients with baseline Gal − 3 > 14.57 pg/ml or ALD > 243.61 pg/ml and patients with Gal − 3 ≤ 14.57 pg/ml + ALD ≤ 243.61 pg/ml (57% vs. 14% vs. 9%, p < 0.01, respectively).

Conclusion

AF recurrence after RFCA had higher baseline Gal-3 and ALD levels, and higher preoperative circulating Gal-3 and ALD levels were independent predictors of AF recurrence for patients undergoing RFCA, while combination of preoperative Gal-3 and ALD levels has higher prediction accuracy.

Exploration of Mechanisms of Sacubitril/Valsartan in the Treatment of Cardiac Arrhythmias Using a Network Pharmacology Approach

Significant reductions in the incidence of cardiac arrhythmia (CA) and sudden cardiac death (SCD), along with amelioration of heart failure, have been reported for treatment with Sacubitril/valsartan (SV). However, its anti-arrhythmic mechanism remains unclear. The current study aims to explore the anti-arrhythmic molecular mechanism of SV. The direct protein targets (DPT) of SV were extracted from DrugBank. The protein-protein interaction (PPI) network of SV DPTs was constructed using STRING, and the indirect protein targets (IPTs) were also identified. A search for arrhythmia-related genes was conducted using GeneCards and the Comparative Toxicogenomics Database (CTD). The DTPs, ITPs, and arrhythmia-related genes from the two datasets were combined in a Venn diagram, and the overlapping genes were identified as core target genes. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses identified the top 20 biological processes and signaling pathways related to disease and the therapeutic effects of SV. The renin-angiotensin system, adrenergic signaling in cardiomyocytes, and gap junction pathways are strongly implicated in the effects of SV on CA. In conclusion, our bioinformatics analyses provided evidence pertaining to the possible antiarrhythmic mechanisms of SV and may contribute to the development of novel drugs for CA.

Angiotensin (ang) 1-7 inhibits ang II-induced atrial fibrosis through regulating the interaction of proto-oncogene tyrosine-protein kinase Src (c-Src) and Src homology region 2 domain-containing phosphatase-1 (SHP-1))

To verify whether Ang-(1-7) produces an antagonistic effect on Ang II-mediated atrial remodeling. Ang II–induced HL-1 cell model and a rat model of Ang II–induced atrial remodeling were constructed and intervened with Ang II Ang-(1-7), AngII +Ang-(1-7), Ang II+ c-Src specific inhibitor (SU6656), and Ang II + Ang-(1-7) + SSG (SHP-1/2 specific inhibitor, stibogluconate), respectively. The systolic blood pressure of the rat caudal artery was detected. And trial fibrosis was detected by Picrosirius red staining and Masson’s trichrome staining. Expressions of transforming growth factor-β (TGF-β), tissue inhibitor of metalloproteinases 1 (TIMP1), Matrix metalloproteinase 2 (MMP-2), connective tissue growth factor (CTGF), galectin-3, α-smooth muscle actin (α-SMA), and collagen I/III were subjected to qPCR and western blot. Furthermore, SHP-1 binding to c-Src was verified by co-immunoprecipitation (Co-IP). Results showed that the expressions of TGF-β, TIMP1, MMP-2, CTGF, α-SMA, galectin-3, and collagen I were increased markedly in the Ang II intervention group, and the expressions of p-ERK1/2, p-Akt, and p-p38MAPK were also increased dramatically. Ang-(1-7) or SU6656 addition could inhibit the action of Ang II factor, thereby minimizing the expressions of the previously described genes and proteins. Simultaneously, SSG supplement reversed the antagonistic effect of Ang-(1-7) on Ang II, and the latter elevated the blood pressure and induced atrial fibrosis in rats. Ang-(1-7) could reverse the changes related to Ang II–induced atrial fibrosis in rats. In conclusion, Ang-(1-7) antagonized Ang II–induced atrial remodeling by regulating SHP-1 and c-Src, thereby affecting the MAPKs/Akt signaling pathway.

Alamandine: Potential Protective Effects in SARS-CoV-2 Patients

Coronavirus disease 2019 (COVID-19) can occur due to contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has no confined treatment and, consequently, has high hospitalization and mortality rates. Moreover, people who contract COVID-19 present systemic inflammatory spillover. It is now known that COVID-19 pathogenesis is linked to the renin-angiotensin system (RAS). COVID-19 invades host cells via the angiotensin-converting enzyme 2 (ACE2) receptor—as such, an individual's susceptibility to COVID-19 increases alongside the upregulation of this receptor. COVID-19 has also been associated with interstitial pulmonary fibrosis, which leads to acute respiratory distress, cardiomyopathy, and shock. These outcomes are thought to result from imbalances in angiotensin (Ang) II and Ang-(1-7)/alamandine activity. ACE2, Ang-(1-7), and alamandine have potent anti-inflammatory properties, and some SARS-CoV-2 patients exhibit high levels of ACE2 and Ang-(1-7). This phenomenon could indicate a failing physiological response to prevent or reduce the severity of inflammation-mediated pulmonary injuries. Alamandine, which is another protective component of the RAS, has several health benefits owing to its antithrombogenic, anti-inflammatory, and antifibrotic characteristics. Alamandine alleviates pulmonary fibrosis via the Mas-related G protein-coupled receptor D (MrgD). Thus, a better understanding of this pathway could uncover novel pharmacological strategies for altering proinflammatory environments within the body. Following such strategies could inhibit fibrosis after SARS-CoV-2 infection and, consequently, prevent COVID-19.

The Relationship Between Valproate and Lamotrigine/Levetiracetam Use and Prognosis in Patients With Epilepsy and Heart Failure: A Danish Register-Based Study

OBJECTIVE

To compare the hazard for all-cause mortality and mortality due to heart failure (HF) between valproate (VPA) and levetiracetam (LEV)/lamotrigine (LTG) users in patients aged ≥ 65 with comorbidities of epilepsy and HF.

METHODS

This was a cohort study using Danish registers during the period from January 1996 to July 2018. The study population included new users of LTG, LEV or VPA. A Cox regression model was used to compute crude and adjusted hazard ratios for the outcome, using an intention-to-treat approach. Average treatment effects (eg, 1-year absolute risks), risk differences and the ratio of risks were computed using the G-formula based on a Cox regression model for the outcomes at the end of the follow-up period.

RESULTS

We included 1345 subjects in the study population. VPA users (n = 696), when compared to LTG/LEV users (n = 649), had an increased hazard of mortality due to HF (hazard ratio [HR] 2.39; 95% CI 1.02-5.60) and to all-cause mortality (HR 1.37; 95% CI 1.01-1.85) in both crude and adjusted analyses. The 1-year absolute risks for all-cause mortality were 29% (95% CI 25%-33%) and 22% (95% CI 18%-26%) for VPA and LTG/LEV users. For mortality due to HF, 1-year absolute risks were 5% (95% CI 3%-7%) and 2% (95% CI 1%-4%) for VPA and LTG/LEV users. The average risk ratio, with LTG/LEV as the reference group, was 1.31 (95% CI 1.02-1.71) for all-cause mortality and 2.35 (95% CI 1.11-5.76) for HF mortality.

CONCLUSION

In older people with HF and epilepsy, treatment with VPA was associated with a higher risk of all-cause and HF mortality compared to treatment with LTG and LEV.

Renin-angiotensin system modulators in COVID-19 patients with hypertension: friend or foe?

Background: ACE2, a component of the non-classic renin-angiotensin system (RAS), acts as a functional receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2) spike protein, which enables the entry of the virus into the host cells. Non-classical ACE2 is one of two types of ACE2 that has a protective effect on vascular and respiratory cells. RAS modulators like angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are among the first-line treatment for hypertensive patients. An upregulation in ACE2 levels with RAS modulators was observed in few preclinical studies, which raised concerns regarding possible increased infectivity among patients treated with RAS modulators.Method: For shortlisting the outcome effects, open-ended, English-restricted databases, published literature, and various clinical studies performed utilizing RAS modulators in COVID 19 patients were considered. Conclusion: Current evidence reveals no increased risk of COVID-19 infection among hypertensive patients on ACEIs/ARBs compared to other antihypertensive medications. Several studies have demonstrated no detrimental effects of RAS modulators on clinical severity, hospital/intensive care unit stay, ventilation and mortality.  Hence, we can conclude that neither ARBs nor ACEIs treatment will cause any side effects or undesirable interactions in COVID-19 infected hypertensive patients.

Role of the Renin-Angiotensin-Aldosterone and Kinin-Kallikrein Systems in the Cardiovascular Complications of COVID-19 and Long COVID

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the virus responsible for the COVID-19 pandemic. Patients may present as asymptomatic or demonstrate mild to severe and life-threatening symptoms. Although COVID-19 has a respiratory focus, there are major cardiovascular complications (CVCs) associated with infection. The reported CVCs include myocarditis, heart failure, arrhythmias, thromboembolism and blood pressure abnormalities. These occur, in part, because of dysregulation of the Renin-Angiotensin-Aldosterone System (RAAS) and Kinin-Kallikrein System (KKS). A major route by which SARS-CoV-2 gains cellular entry is via the docking of the viral spike (S) protein to the membrane-bound angiotensin converting enzyme 2 (ACE2). The roles of ACE2 within the cardiovascular and immune systems are vital to ensure homeostasis. The key routes for the development of CVCs and the recently described long COVID have been hypothesised as the direct consequences of the viral S protein/ACE2 axis, downregulation of ACE2 and the resulting damage inflicted by the immune response. Here, we review the impact of COVID-19 on the cardiovascular system, the mechanisms by which dysregulation of the RAAS and KKS can occur following virus infection and the future implications for pharmacological therapies.

Inhibition of the renin-angiotensin-aldosterone system prevents and cures atrial fibrillation: An overview of systematic reviews

Background: Atrial fibrillation (AF) is a type of arrhythmia that represents a severe health hazard. The current therapies for AF have achieved success in some conditions. However, because the mechanisms underlying the occurrence and development of this disease remain unclear, the current treatment for AF often does not achieve the desired outcomes. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), which exert robust effects on specific cardiovascular diseases, are widely used in the clinic. Several studies are focusing on the effect of ACEIs/ARBs on the prevention and cure of AF. Some systematic reviews have obtained different and even opposite results. An overview is required to obtain a conclusion and provide strong evidence to guide clinical work.Methods: We searched 5 databases, including MEDLINE, EMBASE, Cochrane Library, Web of Science, and CNKI (Chinese), and selected relevant reviews that passed the assessment we performed. Then, we synthesized the data for each result from the included reviews and obtained conclusions.Results: ACEIs/ARBs prevented new-onset AF and AF after heart failure. ACEIs/ARBs performed well in the prevention of secondary AF, especially postoperative AF. However, for patients suffering from hypertension and myocardial infarction, ACEIs/ARBs were not the right choices for preventing AF.Conclusions: We suggest that physicians select ACEIs/ARBs as an anti-AF therapy for patients with heart failure due to their additional benefits. Moreover, for patients who have suffered AF, ACEIs/ARBs may be a routine drug for secondary prevention.

The Role of Renin-Angiotensin-Aldosterone System in the Heart and Lung: Focus on COVID-19

The renin-angiotensin-aldosterone system (RAAS) firstly considered as a cardiovascular circulating hormonal system, it is now accepted as a local tissue system that works synergistically or independently with the circulating one. Evidence states that tissue RAAS locally generates mediators with regulatory homeostatic functions, thus contributing, at some extent, to organ dysfunction or disease. Specifically, RAAS can be divided into the traditional RAAS pathway (or classic RAAS) mediated by angiotensin II (AII), and the non-classic RAAS pathway mediated by angiotensin 1–7. Both pathways operate in the heart and lung. In the heart, the classic RAAS plays a role in both hemodynamics and tissue remodeling associated with cardiomyocyte and endothelial dysfunction, leading to progressive functional impairment. Moreover, the local classic RAAS may predispose the onset of atrial fibrillation through different biological mechanisms involving inflammation, accumulation of epicardial adipose tissue, and electrical cardiac remodeling. In the lung, the classic RAAS regulates cell proliferation, immune-inflammatory response, hypoxia, and angiogenesis, contributing to lung injury and different pulmonary diseases (including COVID-19). Instead, the local non-classic RAAS counteracts the classic RAAS effects exerting a protective action on both heart and lung. Moreover, the non-classic RAAS, through the angiotensin-converting enzyme 2 (ACE2), mediates the entry of the etiological agent of COVID-19 (SARS-CoV-2) into cells. This may cause a reduction in ACE2 and an imbalance between angiotensins in favor of AII that may be responsible for the lung and heart damage. Drugs blocking the classic RAAS (angiotensin-converting enzyme inhibitors and angiotensin receptor blockers) are well known to exert a cardiovascular benefit. They are recently under evaluation for COVID-19 for their ability to block AII-induced lung injury altogether with drugs stimulating the non-classic RAAS. Herein, we discuss the available evidence on the role of RAAS in the heart and lung, summarizing all clinical data related to the use of drugs acting either by blocking the classic RAAS or stimulating the non-classic RAAS.

Protective Effects of Sodium-Glucose Transporter 2 Inhibitors on Atrial Fibrillation and Atrial Flutter: A Systematic Review and Meta- Analysis of Randomized Placebo-Controlled Trials

Background

Hyperglycemia is associated with an increased risk of developing atrial fibrillation (AF) and atrial flutter (AFL). Sodium-glucose transporter 2 inhibitors (SGLT2i) have been reported to prevent AF/AFL in some studies, but not others. Therefore, a meta-analysis was performed to investigate whether SGLT2i use is associated with lower risks of AF/AFL.

Methods

PubMed, Scopus, Web of Science, Cochrane library databases were searched for randomized placebo-controlled trials comparing SGLT2i and placebo.

Results

A total of 33 trials involving 66,685 patients were included. The serious adverse events (SAEs) of AF/AFL occurrence were significantly lower in the SGLT2i group than the placebo group (0.96% vs. 1.19%; RR 0.83; 95% CI 0.71-0.96; P = 0.01; I2 25.5%). Similarly, the SAEs of AF occurrence was significantly lower in the SGLT2i group (0.82% vs. 1.06%; RR 0.81; 95% CI 0.69-0.95; P = 0.01; I2 10.2%). The subgroup analysis showed that the reduction in AF/AFL was significant only for dapagliflozin (1.02% vs. 1.49%; RR 0.73; 95% CI 0.59-0.89; P = 0.002; I2 0%), but not for canagliflozin (1.00% vs 1.08%; RR 0.83; 95% CI 0.62-1.12; P = 0.23; I2 0%), empagliflozin (0.88% vs 0.70%; RR 1.20; 95% CI 0.76-1.90; P = 0.43; I2 0%), ertugliflozin (1.01% vs 0.96%; RR 1.08; 95% CI 0.66-1.75; P = 0.76; I2 0%), and sotagliflozin (0.16% vs 0.10%; RR 1.09; 95% CI 0.13-8.86; P = 0.93; I2 0%).

Conclusions

SGLT2i use is associated with a 19.33% lower SAEs of AF/AFL compared with the placebo. Dapagliflozin users had the lowest SAEs of AF/AFL incidence. Further studies are needed to determine whether canagliflozin, empagliflozin, ertugliflozin, and sotagliflozin similarly exert protective effects against AF/AFL development.

The Tissue Renin-Angiotensin System and Its Role in the Pathogenesis of Major Human Diseases: Quo Vadis?

Evidence has arisen in recent years suggesting that a tissue renin-angiotensin system (tRAS) is involved in the progression of various human diseases. This system contains two regulatory pathways: a pathological pro-inflammatory pathway containing the Angiotensin Converting Enzyme (ACE)/Angiotensin II (AngII)/Angiotensin II receptor type 1 (AGTR1) axis and a protective anti-inflammatory pathway involving the Angiotensin II receptor type 2 (AGTR2)/ACE2/Ang1–7/MasReceptor axis. Numerous studies reported the positive effects of pathologic tRAS pathway inhibition and protective tRAS pathway stimulation on the treatment of cardiovascular, inflammatory, and autoimmune disease and the progression of neuropathic pain. Cell senescence and aging are known to be related to RAS pathways. Further, this system directly interacts with SARS-CoV 2 and seems to be an important target of interest in the COVID-19 pandemic. This review focuses on the involvement of tRAS in the progression of the mentioned diseases from an interdisciplinary clinical perspective and highlights therapeutic strategies that might be of major clinical importance in the future.

Caveolin-3 is required for regulation of transient outward potassium current by angiotensin II in mouse atrial myocytes

Angiotensin II (AngII) is a key mediator of the renin-angiotensin system and plays an important role in the regulation of cardiac electrophysiology by affecting various cardiac ion currents, including transient outward potassium current, Ito. AngII receptors and molecular components of Ito, Kv4.2 and Kv4.3 channels, have been linked to caveolae structures. However, their functional interaction and the importance of such proximity within 50- to 100-nm caveolar nanodomains remain unknown. To address this, we studied the mechanisms of Ito regulation by AngII in atrial myocytes of wild-type (WT) and cardiac-specific caveolin-3 (Cav3) conditional knockout (Cav3KO) mice. We showed that in WT atrial myocytes, a short-term (2 h) treatment with AngII (5 µM) significantly reduced Ito density. This effect was prevented 1) by a 30-min pretreatment with a selective antagonist of AngII receptor 1 (Ang1R) losartan (2 µM) or 2) by a selective inhibition of protein kinase C (PKC) by BIM1 (10 µM). The effect of AngII on Ito was completely abolished in Cav3-KO mice, with no change in a baseline Ito current density. In WT atria, Ang1Rs co-localized with Cav3, and the expression of Ang1Rs was significantly decreased in Cav3KO in comparison with WT mice, whereas no change in Kv4.2 and Kv4.3 protein expression was observed. Overall, our findings demonstrate that Cav3 is involved in the regulation of Ang1R expression and is required for the modulation of Ito by AngII in mouse atrial myocytes.NEW & NOTEWORTHY Angiotensin II receptor 1 is associated with caveolae and caveolar scaffolding protein caveolin-3 in mouse atrial myocytes that is required for the regulation of Ito by angiotensin II. Downregulation of caveolae/caveolin-3 disrupts this regulation and may be implicated in pathophysiological atrial remodeling.

Research Progress on the Cardiac Injury from ACE2 Targeting in SARS-CoV-2 Infection

The epidemic due to the novel coronavirus (SARS-CoV-2) is now a global concern, posing a severe threat to the health of populations. At present, all countries in the world are stepping up the development of vaccines and antiviral agents to prevent the infection and further transmission of SARS-CoV-2. An in-depth investigation of the target organs and pathogenesis regarding SARS-CoV-2 infection will be beneficial for virus therapy. Besides pulmonary injury, SARS-CoV-2 also causes cardiac injury, but the exact mechanisms are unclear. This review summarizes the essential structural characteristics of SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE2), describes the cardiac manifestations following SARS-CoV-2 infection, and explores the mechanisms of cardiac injury targeting ACE2 after the viral invasion. We aim to help the timely detection of related symptoms and implementation of therapeutic measures by clinicians for SARS-CoV-2 infection.

Male predisposition to severe COVID-19: Review of evidence and potential therapeutic prospects

The severe form of COVID-19 has significant sex disparities, with high fatalities commonly reported among males than females. The incidence of COVID-19 has also been higher in males compared with their female counterparts. This trend could be attributed to a better responsive and robust immune system in females. Cytokine storm is one of the pathophysiological features of severe COVID-19, and it occurs as a result of over-activation of immune cells leading to severe inflammation and tissue damage. Nevertheless, it is well modulated in females compared to their male counterparts. Severe inflammation in males is reported to facilitate progression of mild to severe COVID-19. The sex hormones, estrogens and androgens which exist in varying functional levels respectively in females and males are cited as the underlying cause for the differential immune response to COVID-19. Evidence abounds that estrogen modulate the immune system to protect females from severe inflammation and for that matter severe COVID-19. On the contrary, androgen has been implicated in over-activation of immune cells, cytokine storm and the attendant severe inflammation, which perhaps predispose males to severe COVID-19. In this review efforts are made to expand understanding and explain the possible roles of the immune system, the sex hormones and the angiotensin-converting enzyme (ACE) systems in male bias to severe COVID-19. Also, this review explores possible therapeutic avenues including androgen deprivation therapy (ADT), estrogen-based therapy, and ACE inhibitors for consideration in the fight against COVID-19.

Cardiac arrhythmias in patients with COVID-19

The emergence of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a major global public health concern. Although SARS-CoV-2 causes primarily respiratory problems, concurrent cardiac injury cannot be ignored since it may be an independent predictor for adverse outcomes. Cardiac arrhythmias are often observed in patients with COVID-19, especially in severe cases, and more likely contribute to the high risk of adverse outcomes. Arrhythmias should be regarded as one of the main complications of COVID-19. Mechanistically, a number of ion channels can be adversely affected in COVID-19, leading to alterations in cardiac conduction and/or repolarization properties, as well as calcium handling, which can predispose to cardiac arrhythmogenesis. In addition, several antimicrobials that are currently used as potential therapeutic agents for COVID-19, such as chloroquine, hydroxychloroquine and azithromycin, have uncertain benefit, and yet may induce electrocardiographic QT prolongation with potential ventricular pro-arrhythmic effects. Continuous electrocardiogram monitoring, accurate and prompt recognition of arrhythmias are important. The present review focuses on cardiac arrhythmias in patients with COVID-19, its underlying mechanisms, and proposed preventive and therapeutic strategies.

Renin-Angiotensin System and Coronavirus Disease 2019: A Narrative Review

Although clinical manifestations of the 2019 novel coronavirus disease pandemic (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), are mainly respiratory symptoms, patients can also develop severe cardiovascular damage. Therefore, understanding the damage caused by SARS-COV-2 to the cardiovascular system and the underlying mechanisms is fundamental. The cardiovascular damage may be related to the imbalance of the renin-angiotensin-system (RAS) as this virus binds the Angiotensin-Converting-Enzyme 2 (ACE2), expressed on the lung alveolar epithelial cells, to enter into cells. Virus internalization may cause a downregulation of ACE2 on host cell surface that could lead to a local increased level of angiotensin II (AII) and a reduced level of angiotensin 1-7 (A1-7). An imbalance between these angiotensins may be responsible for the lung and heart damage. Pharmacological strategies that interfere with the viral attachment to ACE2 (umifenovir and hydroxychloroquine/chloroquine) or that modulate the RAS (analogous of A1-7 and ACE2, losartan) are in clinical development for COVID-19. The use of RAS inhibitors has also become a matter of public concern as these drugs may increase the mRNA expression and levels of ACE2 and impact the virulence and transmission of SARS-COV-2. Data on the effect of RAS inhibitors on ACE2 mRNA expression are scarce. Scientific societies expressed their opinion on continuing the therapy with RAS inhibitors in patients with COVID-19 and underlying cardiovascular diseases. In conclusion, RAS may play a role in SARS-COV-2-induced cardiac and pulmonary damage. Further studies are needed to better understand the role of RAS in COVID-19 and to guide decision on the use of RAS inhibitors.

Attenuation of atrial remodeling by aliskiren via affecting oxidative stress, inflammation and PI3K/Akt signaling pathway

INTRODUCTION

Atrial fibrillation (AF) is the most common type of arrhythmia. Atrial remodeling is a major factor to the AF substrate. The purpose of the study is to explore whether aliskiren (ALS) has a cardioprotective effect and its potential molecular mechanisms on atrial remodeling.

METHODS

In acute experiments, dogs were randomly assigned to Sham, Paced and Paced+aliskiren (10 mg kg^-1) (Paced+ALS) groups, with 7 dogs in each group. Rapid atrial pacing (RAP) was maintained at 600 bpm for 2 h for paced and Paced+ALS groups and atrial effective refractory periods (AERPs), inducibility of AF (AFi) and average duration time (ADT) were measured. In chronic experiments, there were 5 groups: Sham, Sham+ALS, Paced, Paced+ALS and Paced+ALS+PI3K antagonist wortmannin (WM) (70 μg kg^-1 day^-1). RAP at 500 beats/min was maintained for 2 weeks. Inflammation and oxidative stress indicators were measured by ELISA assay, echocardiogram and pathology were used to assess atrial structural remodeling, phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/Akt) signaling pathways were studied by RT-PCR and western blotting to evaluate whether the cardioprotective effect of ALS works through PI3K/Akt signaling pathway.

RESULTS

The electrophysiological changes were observed after 2-h pacing. The AERP shortened with increased AFi and ADT, which was attenuated by ALS (P < 0.05). After pacing for 2 weeks, oxidative stress and inflammation markers in the Paced group were significantly higher than those in the Sham group (P < 0.01) and were reduced by ALS treatment (P < 0.01). The reduced level of antioxidant enzymes caused by RAP was also found to be elevated in ALS-treated group (P < 0.01). The results of pathology and echocardiography showed that RAP can cause atrial enlargement, fibrosis (P < 0.01), and were attenuated in ALS treatment group. The PI3K/Akt signaling pathway were downregulated induced by RAP. ALS could upregulate the PI3K/Akt pathway expression (P < 0.05). Furthermore, the cardioprotective effects in structural remodeling of ALS were suppressed by WM.

CONCLUSIONS

ALS may offer cardioprotection in RAP-induced atrial remodeling, which may partly be ascribed to its anti-inflammatory and anti-oxidative stress action and the regulation of PI3K/Akt signaling pathway.