Inflammation, Inflammasome Activation, and Atrial Fibrillation

Prevention of New-Onset Heart Failure in Atrial Fibrillation: The Role of Pharmacological Management

Atrial fibrillation (AF) is the most common type of chronic arrythmia, with a lifetime prevalence of one in every three to five individuals above the age of 45 years. The higher heart rate, abnormal rhythm and inflammation caused by AF lead to changes in the function and structure of the heart. This, over time, can culminate in heart failure. In patients with AF, the lifetime prevalence of new-onset heart failure is twice that of stroke. The development of new-onset heart failure in AF is associated with high mortality. Despite the emphasis that AF guidelines put on preventing cardiovascular comorbidities, there is limited evidence regarding pharmacological therapies to prevent incident heart failure in individuals with AF. Specifically, the association between the use of rate control agents and incident heart failure in this population is unknown. Whilst rhythm control may reduce the risk of heart failure, the comparative effect of each pharmacological agent is not clear. In select subgroups of patients with AF, the choice of direct-acting oral anticoagulants and their optimal dosing has been attributed to a lower risk of new-onset heart failure. Future research is needed to identify an evidence-based approach to minimizing the development of heart failure in patients with AF.

Role of ferroptosis in atrial fibrillation: a review

Cardiovascular disease remains the leading cause of mortality, with atrial fibrillation emerging as one of the most common conditions encountered in clinical practice. However, its underlying mechanisms remain poorly understood, prompting ongoing research. Ferroptosis, a recently discovered form of regulated cell death characterized by lipid peroxidation and disrupted cellular redox balance leading to cell death due to iron overload, has attracted significant attention. Since its identification, ferroptosis has been extensively studied in various contexts, including cancer, stroke, myocardial ischemia/reperfusion injury, and heart failure. Growing evidence suggests that ferroptosis may also play a critical role in the onset and progression of atrial fibrillation, though research in this area is still limited. This article provides a concise overview of the potential mechanisms by which ferroptosis may contribute to the pathogenesis of atrial fibrillation.

Therapeutic Potential of Gasdermin D-Mediated Myocardial Pyroptosis in Ischaemic Heart Disease: Expanding the Paradigm From Bench to Clinical Insights

Ischaemic heart disease (IHD) remains a leading cause of global morbidity and mortality. One significant contributor to the pathology of IHD is the excessive release of inflammatory mediators during the disease progression. Pyroptosis is a form of programmed cell death (PCD) triggered by the activation of inflammasomes and caspase 1. The activation of inflammatory caspase 1 proteolytically cleaves gasdermin D (GSDMD) to the activated form amino acid terminus (GSDMD-NT), leading to disruption of the plasma membrane. This cascade of events is considered the canonical pathway of pyroptosis. IHD also caused oxidative stress, thereby triggering noncanonical pyroptosis via the activation of caspases 4/5/11. Previous studies have provided compelling evidence of the close relationship between pyroptosis and the aetiology of IHD (e.g., acute myocardial infarction, myocardial ischaemia and reperfusion injury and chronic myocardial infarction), as well as the association of pyroptosis with unfavourable clinical outcomes. Several interventions aimed at targeting pyroptosis have demonstrated promising therapeutic benefits against IHD-related pathologies. This review provides mechanistic insights into the roles of pyroptosis in IHD from in vitro, in vivo and clinical perspectives. In-depth understanding into this area could also pave the way for the future development of novel therapeutic strategies targeting pyroptosis in IHD.

Amlexanox reduces new-onset atrial fibrillation risk in sepsis by downregulating S100A12: a Mendelian randomization study

Background

Sepsis is characterized by high morbidity and mortality rates, alongside limited therapeutic efficacy. Atrial fibrillation (AF), the most common arrhythmia, has been closely linked to sepsis in prior research. However, the specific mechanisms through which sepsis leads to new-onset AF remain poorly understood. This study focuses on identifying critical genes that are dysregulated in the development of new-onset AF within the context of sepsis, with the goal of uncovering new potential targets for its diagnosis and prevention.

Material and methods

Our study began by applying Mendelian Randomization (MR) to assess the causal link between sepsis and AF. We then sourced sepsis and AF datasets from the Gene expression Omnibus (GEO) database. Using Weighted Gene Co-expression Network Analysis (WGCNA), we pinpointed key modules and genes associated with both sepsis and AF conditions. Protein-protein interaction (PPI) network was constructed. The Transcriptional Regulatory Relationships Unravelled by Sentence-based Text-mining (TRRUST) database helped build the transcription factor (TF) interaction network. Key genes were scrutinized through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) to delve into their roles in new-onset AF's pathophysiology during sepsis. We employed the CIBERSORT algorithm to evaluate immune infiltration and the association between key genes and immune cells. The Connectivity Map (CMap) database facilitated the prediction of potential small molecule compounds targeting key genes. To culminate, an acute sepsis mouse model was developed to validate the implicated mechanisms of key genes involved in new-onset AF during sepsis, and to assess the prophylactic effectiveness of identified drug candidates.

Results

MR revealed potential independent risk factors for new-onset AF in sepsis. S100A12 was identified as a core interaction gene with elevated levels in sepsis and AF, underscoring its diagnostic and predictive significance. S100A12, along with associated genes, was mainly linked to immune and inflammatory response signaling pathways, correlating with immune cell levels. Targeting S100A12 identifies five potential small molecule therapeutics: amlexanox, balsalazide, methandriol, olopatadine, and tiboloe. In animal studies, acute sepsis increased S100A12 expression in serum and atrial tissues, correlating positively with inflammatory markers (IL-1β, IL-6, TNF-α) and negatively with heart rate, indicating a predisposition to AF. Early amlexanox administration can reduced S100A12 expression, dampened inflammation, and lessened new-onset AF risk in sepsis.

Conclusion

This study demonstrates that sepsis may independently increase the risk of new-onset AF. We identified S100A12 as a key gene influencing the new-onset AF in sepsis through immune regulation, presenting considerable diagnostic and predictive value. Notably, amlexanox, by targeting S100A12 emerges as the most clinical relevant intervention for managing new-onset AF in sepsis patients.

Inflammation in liver fibrosis and atrial fibrillation: A prospective population-based proteomic study

Background & Aims

Elevated liver stiffness has been associated with atrial fibrillation (AFib) in the general population. The mechanism underlying this association is unclear.

Methods

Participants were recruited from the general population and prospectively enrolled with follow-up for 5 years. The fibrosis-4 (FIB-4) index was used as a surrogate marker for liver fibrosis. Proteomics analysis was performed using the 92-target Olink inflammation panel. Validation was performed using the NAFLD fibrosis score (NFS), aspartate aminotransferase to platelet index (APRI), and repeat confirmation proteomics.

Results

A sample of 11,509 participants with a mean age of 54.0 ± 11.1 years, 51.3% women, and a median FIB-4 index of 0.85 (0.65/1.12), was used. The FIB-4 index was predictive for prevalent (FIB-4 index adjusted odds ratio (aOR) per SD: 1.100 with 95% CI 1.011-1.196; p = 0.026), but not incident AFib (log[FIB-4 index]) adjusted hazard ratio: 1.125 with 95% CI 0.943-1.342, p = 0.19). Elastic net regularized regression identified CCL20, DNER, and CXCL10 for prevalent AFib, and AXIN1, CXCL10, and Flt3L for the log(FIB-4 index) (per SD) as most important in common regulated proteins. The relationship between the FIB-4 index, the identified proteins, and AFib was relevant and reproduced at the 5-year follow-up for CXCL10 after adjusting for confounders (log[FIB-4 index] per SD - CXCL10 [per SD] adjusted β 0.160 with 95% CI 0.127-0.194, p <0.0001; CXCL10 [per SD] - AFib aOR 1.455 with 95% CI 1.217-1.741, p <0.0001), reproduced using the NFS and APRI, and corresponding to increased serum levels.

Conclusions

CXCL10 is linked to liver fibrosis, as determined by the FIB-4 index, and to prevalent AFib.

Impact and implications

How elevated liver stiffness relates to atrial fibrillation in the general population remains to be clarified. We hypothesized that systemic inflammation against a background of liver fibrosis produced from metabolic dysfunction-associated steatotic liver disease (MASLD), is involved in the pathophysiology of atrial fibrillation. Using large-scale targeted proteomics, we found that CXCL10 is related to both liver fibrosis, as defined by the fibrosis-4 index, and to atrial fibrillation. These results can aid evidence-based drug development for patients with atrial fibrillation and MASLD-related liver fibrosis.

Association between interleukin-6 levels and stroke: a systematic review and meta-analysis

OBJECTIVES

We aimed to evaluate the association of interleukin-6 (IL-6) expression levels with stroke.

METHODS

According to the set search strategy, we systematically screened relevant studies using PubMed and extracted study results regarding IL-6 from the literature for comprehensive quantitative analysis to explore the relationship between IL-6 level and stroke risk.

RESULTS

This study included 15 publications with a total of 1696 participants, with 975 cases in the case group and 721 cases in the control group. Meta-analysis showed that IL-6 levels were significantly higher in the stroke population than those in the control group (standardized mean difference = 1.22, 95% confidence interval = 0.79-1.64). Subgroup analysis showed that there was no significant difference in heterogeneity for IL-6 detection methods between the two groups (I2 = 0, P = 0.47). The difference in heterogeneity test results regarding geographic region was statistically significant (I2 = 89.7%, P < 0.01). The results of heterogeneity testing for mean participant age were also statistically significant (I2 = 84.3%, P = 0.01).

CONCLUSION

The present study results showed that IL-6 may be significantly associated with stroke development.

Left atrial reservoir strain is a marker of atrial fibrotic remodeling in patients undergoing cardiovascular surgery: Analysis of gene expression

Left atrial strain (LAS) measured by two-dimensional speckle tracking echocardiography (2DSTE) is considered to be a marker of LA structural remodeling, but it remains unsettled. We investigated the potential usefulness and clinical relevance of LAS to detect atrial remodeling including fibrosis by analyzing gene expression in cardiovascular surgery patients. Preoperative 2DSTE was performed in 131 patients (92 patients with sinus rhythm [SR] patients including paroxysmal AF [PAF], 39 atrial fibrillation [AF]) undergoing cardiovascular surgery. Atrial samples were obtained from the left atrial appendages, and mRNA expression level was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR) in 59 cases (24 PAF, 35 AF). Mean value of left atrial reservoir strain (mLASr) correlated with left atrial volume index (LAVI), and left atrial conduit strain (mLAScd). mLASr also correlated with left atrial contractile strain (mLASct) in SR patients including PAF. mLASr was significantly lower, and LAVI was higher, in the AF group, compared with SR patients including PAF. The expression of COL1A1 mRNA encoding collagen type I α1 significantly increased in AF patients (p = 0.031). mLASr negatively correlated with COL1A1 expression level, and multivariate regression analysis showed that mLASr was an independent predictor of atrial COL1A1 expression level, even after adjusting for age, sex, and BMI. But, neither mLAScd / mLASct nor LAVI (bp) correlated with COL1A1 gene expression. The expression level of COL1A1 mRNA strongly correlated with ECM-related genes (COL3A1, FN1). It also correlated ECM degradation-related genes (MMP2, TIMP1, and TIMP2), pro-fibrogenic cytokines (TGFB1 encoding TGFβ1, END1, PDGFD, CTGF), oxidant stress-related genes (NOX2, NOX4), ACE, inflammation-related genes (NLRP, IL1B, MCP-1), and apoptosis (BAX). Among the fibrosis-related genes examined, univariable regression analysis showed that log (COL1A1) was associated with log (TGFB1) (adjusted R2 = 0.685, p<0.001), log (NOX4) (adjusted R2 = 0.622, p<0.001), log (NOX2) (adjusted R2 = 0.611, p<0.001), suggesting that TGFB1 and NOX4 was the potent independent determinants of COL1A1 expression level. mLASr negatively correlated with the ECM-related genes, and fibrosis-related gene expression level including TGFB1, NOX2, and NLRP3 in PAF patients. PAF patients with low mLASr had higher expression of the fibrosis-related gene expression, compared with those with high mLASr. These results suggest that LASr correlates with atrial COL1A1 gene expression associated with fibrosis-related gene expression. Patients with low LASr exhibit increased atrial fibrosis-related gene expression, even those with PAF, highlighting the utility of LAS as a marker for LA fibrosis in cardiovascular surgery patients.

Effect of nutritional status on adverse clinical events in elderly patients with nonvalvular atrial fibrillation: A retrospective cohort study

OBJECTIVE

To explore the influence of nutritional status on adverse clinical events in elderly patients with nonvalvular atrial fibrillation.

METHODS

This retrospective observational cohort study included 196 patients, 75-102-years-old, with nonvalvular atrial fibrillation, hospitalized in our hospital. The nutritional status was assessed using Mini-Nutritional Assessment-Short Form (MNA-SF). Patients with MNA-SF scores of 0-11 and 12-14 were included in the malnutrition and nonmalnutrition groups, respectively.

RESULTS

The average age of the malnutrition group was higher than that of the nonmalnutrition group, and the levels of body mass index (BMI), hemoglobin (HGB), and albumin (ALB) were significantly lower than those of the nonmalnutrition group, with statistical significance (p < .05). The incidence of all-cause death in the malnutrition group was higher than that in the nonmalnutrition group (p = .007). Kaplan-Meier curve indicated that malnutrition patients have a higher risk of all-cause death (log-rank test, p = .001) and major bleeding events (p = .017). Multivariate Cox proportional hazard regression analysis corrected for confounders showed that malnutrition was an independent risk factor of all-cause death (HR = 1.780, 95%CI:1.039-3.050, p = .036). The malnutrition group had a significantly high incidence of major bleeding than the nonmalnutrition group (p = .026), and there was no significant difference in the proportion of anticoagulation therapy (p = .082) and the incidence of ischemic stroke/systemic embolism (p = .310) between the two groups.

CONCLUSIONS

Malnutrition is an independent risk factor of all-cause death in elderly patients with atrial fibrillation. The incidence of major bleeding in malnourished elderly patients with atrial fibrillation is high, and the benefit of anticoagulation therapy is not obvious.

Single-cell sequencing of immune cells from the coronary sinus reveals immune mechanisms of the progression of persistent atrial fibrillation

Identifying the atlas of immune cells from coronary sinus circulation (CSC) of patients with persistent atrial fibrillation (PerAF) may provide new insights into the role of immune cells in the progression of AF. Single-cell sequencing revealed substantial alterations in immune cells from CSCs of patients with PerAF, especially a markedly elevated abundance of T cells, after which we identified a T cell subset: FGFBP2(+)TRDC(-)CD4(-) T cells (Ftc-T cells), which can promote the proliferation of cardiac fibroblasts (CFs),and the proportion of Ftc-T had a positive linear with AF recurrence post catheter ablation (CA). Moreover, IFI27 was found to be highly enriched in Ftc-T cells and promoted CFs proliferation and collagen expression. Altogether, our findings represent a unique resource providing in-depth insights into the heterogeneity of the immune cell from CSC of patients with PerAF and highlight the potential role of Ftc-T cells and IFI27 for AF progression.

Rivaroxaban Plasma Concentration and Clinical Outcomes on Older Patients with Non-valvular Atrial Fibrillation and Pulmonary Infection

INTRODUCTION

Infection may induce thrombotic and hemorrhagic events; however, it is currently unclear whether the inflammatory response affects the coagulation function and the clinical efficacy and safety of rivaroxaban in older patients with non-valvular atrial fibrillation (NVAF).

OBJECTIVE

This project aimed to assess the effectiveness and safety of the non-vitamin K antagonist oral anticoagulant rivaroxaban in older patients with NVAF complicated by infection, and to provide a basis for possible drug dose adjustment.

METHODS

A total of 152 NVAF patients aged ≥ 65 years admitted to the Fifth People's Hospital of Shanghai from June 2020 to May 2022 were included in this prospective, observational study. The changes in steady-state plasma concentration of rivaroxaban and FXa inhibition rate were compared between patients with and without infection, and the impact on the occurrence of infection, thrombotic events, and bleeding events was compared through 1-year follow-up.

RESULTS

Our results showed that patients in the infection group had abnormal inflammation markers, as well as an increased occurrence of bleeding and thrombotic events during hospitalization and follow-up. The high incidence of bleeding events in patients was closely related to the occurrence of infection, lymphocyte reduction, and increased neutrophil-lymphocyte ratio. The increase in thrombotic events was related to a decrease in rivaroxaban plasma concentration. Bleeding events in patients taking anticoagulant drugs are not necessarily due to drug accumulation.

CONCLUSIONS

Timely control of infection, assessment of bleeding and thrombotic risks, and selection of appropriate anticoagulation treatment strategies should be made in older NVAF patients who develop pulmonary infection.

CLINICAL TRIALS REGISTRATION

Chinese Clinical Trial Registry Number ChiCTR2000033144.

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.

Proteome-Wide Mendelian Randomization Analysis Identified Potential Drug Targets for Atrial Fibrillation

Background Finding effective and safe therapeutic drugs for atrial fibrillation (AF) is an important concern for clinicians. Proteome-wide Mendelian randomization analysis provides new ideas for finding potential drug targets. Methods and Results Using a proteome-wide Mendelian randomization approach, we assessed the genetic predictive causality between thousands of proteins and AF risk and found that genetically predicted plasma levels of phosphomevalonate kinase, tumor necrosis factor ligand superfamily member 12, sulfhydryl oxidase 2, interleukin-6 receptor subunit alpha, and low-affinity immunoglobulin gamma Fc region receptor II-b might decrease AF risk, while genetically predicted plasma levels of beta-mannosidase, collagen alpha-1(XV) chain, ANXA4 (annexin A4), COF2 (cofilin-2), and RAB1A (Ras-related protein Rab-1A) might increase AF risk (P<3.4×10-5). By using different Mendelian randomization methods and instrumental variable selection thresholds, we performed sensitivity analyses in 30 scenarios to test the robustness of positive findings. Replication analyses were also performed in independent samples to further avoid false-positive findings. Drugs targeting tumor necrosis factor ligand superfamily member 12, interleukin-6 receptor subunit alpha, low-affinity immunoglobulin gamma Fc region receptor II-b, and annexin A4 are approved or in development. The results of the phenome-wide Mendelian randomization analysis showed that changing the plasma levels of phosphomevalonate kinase, cofilin-2, annexin A4, Ras-related protein Rab-1A, sulfhydryl oxidase 2, and collagen alpha-1(XV) chain did not increase the risk of other diseases while decreasing the risk of AF. Conclusions We found a significant causal association between genetically predicted levels of 10 plasma proteins and AF risk. Four of these proteins have drugs targeting them that are approved or in development, and our results suggest the potential for these drugs to treat AF or cause AF. Sulfhydryl oxidase 2, low-affinity immunoglobulin gamma Fc region receptor II-b, and beta-mannosidase have not been suggested by previous laboratory or epidemiological studies to be associated with AF and may reveal new pathophysiological pathways as well as therapeutic targets for AF.

The role of IL-6, IL-10, TNF-α and PD-1 expression on CD4 T cells in atrial fibrillation

Backgrounds

While not completely understood, the electrical, structural, and communication pathways that play a role in the onset and progression of atrial fibrillation (AF) seem to be connected to the intricate interplay between neurohormones and cellular mediators. Our study's objective was to examine how the expression profiles of the inflammatory cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor (TNF), and programmed death 1 (PD-1) changed in Cluster of Differentiation 4 (CD4) T cells depending on whether atrial fibrillation was paroxysmal or permanent. This analysis would provide new diagnostic markers for the detection and management of atrial fibrillation.

Methods

In a cross-sectional study, 60 healthy controls, 49 patients with persistent atrial fibrillation, and 50 patients with paroxysmal atrial fibrillation were compared. Serum biomarker levels are found using the ELISA method, which uses enzyme-linked immunosorbent assay. Echocardiography was used to assess heart function.

Results

Patients with atrial fibrillation had serum concentrations of IL-6, TNF-a, and IL-10 that were considerably higher than but PD-1 was lower those in the non-AF control group and those in patients with persistent atrial fibrillation. According to the diameter of LA and the serum level of NT-proB-type natriuretic peptide (NT-proBNP) is greater than that of patients with paroxysmal atrial fibrillation than control group. Patients with persistent atrial fibrillation had increased serum levels of low-density lipoprotein cholesterol (LDL-C) compared with those without atrial fibrillation. While PD-1 in patients with paroxysmal atrial fibrillation is closely related to C-reactive protein (CRP), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and very low density lipoprotein cholesterol. In addition, PD-1 in patients with persistent atrial fibrillation is closely related to IL-6, TNF-a, and IL-10.

Conclusion

Higher blood concentrations of NT-proBNP, IL-6, IL-10, TNF-, and LDL-C but low level of PD-1 are associated with progression from paroxysmal or chronic AF.

Gut Microbiota and Atrial Fibrillation: Pathogenesis, Mechanisms and Therapies

Over the past decade there has been an interest in understanding the role of gut microbiota in the pathogenesis of AF. A number of studies have linked the gut microbiota to the occurrence of traditional AF risk factors such as hypertension and obesity. However, it remains unclear whether gut dysbiosis has a direct effect on arrhythmogenesis in AF. This article describes the current understanding of the effect of gut dysbiosis and associated metabolites on AF. In addition, current therapeutic strategies and future directions are discussed.

Objectively confirmed gastroesophageal reflux disease and risk of atrial fibrillation: a population-based cohort study in Sweden

OBJECTIVE

This study aimed to determine the risk of atrial fibrillation in patients with objectively confirmed GERD.

METHODS

This was a nationwide population-based cohort study between 2005 and 2018, including the majority ( n = 8 421 115) of all Swedish adult residents (≥18 years). Within this cohort, the exposed group were all individuals with a diagnosis of esophagitis or Barrett's esophagus, and the unexposed group was made up of five times as many individuals without any GERD, matched by age, sex, and calendar year. The outcome was the first diagnosis of atrial fibrillation. Cox regression provided hazard ratios (HRs) with 95% confidence intervals (CIs), adjusted for confounders.

RESULTS

Among 118 013 individuals with esophagitis or Barrett's esophagus and 590 065 without GERD, 7042 (6.0%) and 40 962 (6.9%) developed atrial fibrillation, respectively. The risk of atrial fibrillation among patients with GERD was 13% increased within the first year of diagnosis (HR, 1.13; 95% CI, 1.06-1.20), but was not increased after that. Among individuals aged less than 60 years, the HR of atrial fibrillation was 55% increased within the first year of diagnosis (HR, 1.55; 95% CI, 1.27-1.88), and this association remained increased after the first year (HR, 1.14; 95% CI, 1.06-1.22). No association was found in older participants (≥60 years). Results were similar in men and women.

CONCLUSION

This large population-based cohort study indicates that objectively determined GERD increases the risk of atrial fibrillation shortly after diagnosis in men and women younger than 60 years.

IL-1β is not critical to chronic heart dysfunction in mice with Chagas disease

Long after Trypanosoma cruzi infection, 40% of individuals develop a progressive chronic chagasic cardiomyopathy (CCC), with systolic dysfunction and arrhythmias. Since we previously showed IL-1β mediates the development of systolic dysfunction and cardiac arrhythmias in diabetes mellitus and cardiorenal syndrome, and IL-1β remains elevated in Chagas disease patients, here we tested the role of IL-1β in CCC using a mouse model. Mice deficient in IL-1R expression (Il-1r^−/−) survived acute T. cruzi infection with greater parasitemia than controls but did not lose weight as wild-type (WT) did. At the chronic stage, WT presented prolonged ventricular repolarization intervals (QJ), while Il-1r^−/− presented intervals like noninfected controls. Infected Il-1r^−/− and WT did not differ in stroke volume (SV), the incidence of cardiac arrhythmias on electrocardiography (EKG), whole heart action potential duration (APD), or the incidence of triggered activity after S1–S2 protocol, which is a measure of susceptibility to cardiac arrhythmias. We also treated chronically infected WT mice with an IL-1R antagonist, anakinra. Treatment shortened the QJ interval but did not improve the SV or the incidence of cardiac arrhythmias on EKG. Anakinra failed to reduce triggered activity following the electrical extra-stimulation protocol. In conclusion, the absence of functional IL-1β/IL-1R signaling did not prevent or reverse the decrease of SV or the incidence of cardiac arrhythmias induced by chronic T. cruzi infection, implying this is not a critical mechanism in generating or maintaining CCC. Since similar cardiac abnormalities were previously credited to IL-1β signaling, ruling out this mechanism is important to discourage further attempts of IL-1β blockade as a therapeutical measure.

Colchicine: Emerging therapeutic effects on atrial fibrillation by alleviating myocardial fibrosis in a rat model

Although many research have found that colchicine has general therapeutic effect in cardiovascular disease, the therapeutic mechanism in atrial fibrillation has not been clearly studied. To explore whether colchicine plays a role in the treatment of AF by reducing myocardial fibrosis, we performed a series of studies. Rat models of AF were induced by Ach-CaCl₂ to assess the therapeutic effect of colchicine at doses of 0.8 mg/kg on the duration of AF rhythm, degree of myocardial fibrosis, and secretion of inflammatory factors in the serum. RNA-Seq was also performed to elucidate the possible mechanisms by which colchicine might reduce the alleviation of myocardial fibrosis associated with AF. These studies showed that colchicine reduced the duration of AF and the degree of fibrosis in the left atrium and that it significantly reduced the secretion of TGFβ1, activin A, collagen I, and collagen III. These results suggest that colchicine may reduce myocardial fibrosis by (1) inhibiting the TGFβ1/ALK5 and activin A/ALK4 fibrosis pathways; (2) inhibiting the activation, phenotypic transformation, and apoptosis resistance of myocardial fibroblasts; and (3) reducing the synthesis of inflammatory factors and collagen.

Commensal microbe-derived SCFA alleviates atrial fibrillation via GPR43/NLRP3 signaling

Rationale: Dysbiotic gut microbiota (GM) and NLRP3 inflammasome are proarrhythmic factors in atrial fibrillation (AF). Herein, whether short-chain fatty acid (SCFA) produced from GM fermentation of dietary fiber serving as invisible mediators is yet unclear. Thus, the current study aimed to determine whether SCFA alleviated from NLRP3 signaling-mediated atrial remodeling protects AF development. Methods: First, a cross-sectional study based on the GC-MS metabolomics was performed to explore the association between fecal SCFA levels and AF traits in a cohort consisted of 48 individuals. Then, a well-established mice model fed diet deficient or enriched in dietary fiber was established to elucidate the pathophysiological role of SCFA involved in AF susceptibility, atrial remodeling, and G-protein-coupled receptor 43 (GPR43)/NLRP3 signaling. Finally, the effects of SCFA were verified on HL-1 cells. Results: Fecal SCFA levels were remarkably reduced in AF patients with a declining trend from paroxysmal to persistent AF. Prolonged P wave duration based on surface ECG and increased left atrial diameter gained from echocardiography was identified in low-fiber diet mice but lost in SCFA-supplemented group. Lack of dietary fiber enhanced susceptibility to AF under burst pacing, whereas SCFA might exert a protective effect. The supplementation of SCFA prevented dietary fiber deficiency-upregulated phosphorylation of calmodulin-dependent protein kinase II and ryanodine receptor 2, the disarray fibrosis, collagen expression, and NLRP3 inflammasome activation in atrial tissue. Finally, the AF protective roles of SCFA were identified through GPR43 mediated deactivation of NLRP3 by GPR43 knockdown in HL-1 cells. Conclusions: SCFA derived from dietary fiber fermentation by gut commensals alleviates AF development via GPR43/NLRP3 signaling.

Right Atrial Fluorodeoxyglucose Uptake Is a Risk Factor for Stroke and Improves Prediction of Stroke Above the CHA2DS2-VASc Score in Patients With Atrial Fibrillation

Background

Atrial fibrillation (AF) is a common arrhythmia, and its most severe and dreaded complication is stroke. The CHA2DS2-VASc score is currently recommended for stroke risk assessment in AF. We aimed to explore the relationship between atrial FDG uptake and stroke and whether atrial FDG uptake could provide incremental value above the CHA2DS2-VAS score to predict stroke in AF by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT).

Materials and Methods

From September 2017 to December 2020, we retrospectively enrolled 230 patients (115 with AF and 115 without AF as the non-AF group, matched for the date of PET/CT examination and the basic characteristics of the patient) who underwent 18F-FDG PET/CT due to tumor screening or preoperative staging after prolonged fasting and followed up for at least 12 months from the date of PET/CT examination; the endpoint event is the occurrence of stroke. We visually and quantitatively analyzed 18F-FDG uptake in the right and left atria (RA/LA), right and left atrial appendage (RAA/LAA), right and left ventricle (RV/LV), and collected clinical features. In addition, according to the endpoint event (stroke), the enrolled population was divided into the stroke group and non-stroke group, and relevant clinical features and atrial FDG uptake indicators of the two groups were analyzed. Univariate and multivariate Cox regression analyzes were used to analyze the risk factors of stroke events. The Kaplan–Meier survival curve of atrial FDG uptake was drawn, and the log-rank method was used to compare the differences in the survival curves of the two groups. Receiver operating characteristic (ROC) curves were used to examine the discriminatory power of atrial FDG uptake in predicting stroke and determine whether the addition of atrial FDG uptake improves predictive value beyond the CHA2DS2-VASc score for stroke.

Results

In the AF group, more than half of patients had RA FDG uptake and one-fifth had LA FDG uptake, while one patient had RA FDG uptake and two patients had LA FDG uptake in the non-AF group. In quantitative analysis, the maximum standardized uptake value (SUVmax) of the RA and LA in the AF group was significantly higher than that of the non-AF group (all P &lt; 0.001). We followed up the patients for 28 ± 10 months, and finally, 31 patients had stroke. In the stroke group, atrial fibrillation, RA SUVmax, RAA SUVmax, LAA SUVmax, age ≥ 75 years, and left atrial dilation were significantly higher than those of the non-stroke group (all P &lt; 0.05). Multivariate Cox regression analysis showed that high RA SUVmax (RA SUVmax ≥ 2.62) was an independent risk factor for stroke (HR = 4.264, 95% CI 1.368–13.293, P = 0.012). By using the log-rank test, patients with high RA SUVmax had a significantly higher incidence of stroke compared with patients with low RA SUVmax (P &lt; 0.001). Addition of high RA SUVmax to the CHA2DS2-VASc score could predict stroke more effectively, with a larger AUC 0.790 (P &lt; 0.001).

Conclusion

This study found a significant correlation between atrial FDG uptake and AF, especially in RA. Meanwhile, RA FDG uptake is an independent risk factor for stroke, and patients with high RA SUVmax have a significantly higher risk of stroke. Moreover, RA FDG uptake improves prediction of stroke above the CHA2DS2-VASc score in patients with AF.

C-reactive protein and atrial fibrillation: Insights from epidemiological and Mendelian randomization studies

BACKGROUND AND AIMS

This study aimed to investigate the role of C-reactive protein (CRP) in atrial fibrillation (AF) from epidemiological and genetic perspectives.

METHODS AND RESULTS

Individual-level data from the Kailuan cohort recruited between 2006 and 2017 were included. Serum CRP levels were measured at baseline and at biennial follow-up visits, and incident AF was ascertained from biennial 12-lead ECG assessment and medical records. Cox proportional hazards models were used to assess the association between baseline CRP levels or cumulative exposure to CRP and incident AF. A meta-analysis including nine prospective cohort studies and our current study was also conducted. Mendelian randomization (MR) analysis was performed to evaluate the aetiological role of CRP in AF. In our observational study (n = 86,424), high baseline CRP levels (>3 mg/L), compared with low CRP (<1 mg/L), were not significantly associated with AF risk (HR: 1.18; 95% CI: 0.99-1.40). High cumulative exposure to CRP (HR: 1.49; 95%CI: 1.01-2.21) was significantly associated with an increased risk of AF. Our meta-analysis suggested a positive association between elevated CRP levels and incident AF (relative risk: 1.27; 95% CI: 1.14-1.42). However, no significant association between genetically determined CRP and AF risk was observed in the MR analysis.

CONCLUSION

Evidence from observational studies suggested that elevated serum CRP levels were positively associated with incident AF, while the causal effects of CRP on AF were not supported by the MR analysis.

CLINICAL TRIAL REGISTRATION

URL: https://www.chictr.org.cn; Unique identifier: ChiCTR-TNRC-11001489.

Cardiac Fibroblasts Promote Ferroptosis in Atrial Fibrillation by Secreting Exo-miR-23a-3p Targeting SLC7A11

The exact mechanism of atrial fibrillation (AF) has been not well elucidated. Ferroptosis is an iron-dependent cell death due to excessive accumulation of peroxidized polyunsaturated fatty acids. However, the molecular mechanism underlying AF and ferroptosis has never been reported. Here, we established the rapid pacing model in vivo and vitro to investigate the relationship between AF and ferroptosis. In canine model of rapid atrial pacing, the content of malondialdehyde and total ions in the atrial tissue of the Pacing group was significantly increased and the exosome inhibitor GW4869 reduced ferroptosis, fibrosis, and inflammation and improved histological and electrophysiological remodeling. In rapid pacing h9c2 cells, the expression of antioxidative stress genes associated with ferroptosis presented sequential changes and proteins involved in ferroptosis such as FTH1, SLC7A11, and GPX4 were gradually depleted. Furthermore, pacing cardiac fibroblast-derived exosomes (CF-exos) exacerbated ferroptosis in h9c2 cells and pretreated pacing-CF-exos with GW4869 alleviated injury to h9c2 cells. In mechanism, our results demonstrated that pacing-CF-exos highly expressed miR-23a-3p by informatics analysis and experimental verification. Inhibitor-miR-23a-3p protected h9c2 cells from ferroptosis accompanying with upregulation of SLC7A11. In addition, SLC7A11 was shown to be the target gene of miR-23a-3p. In conclusion, our results suggest that CF-exos-miR-23a-3p may promote ferroptosis. The development of AF in a persistent direction could be prevented by intervening with exosomal miRNAs to reduce oxidative stress injury and ferroptosis.

A phenome-wide bidirectional Mendelian randomization analysis of atrial fibrillation

Background

The prevalence of atrial fibrillation (AF) is increasing with an aging worldwide population, yet a comprehensive understanding of its causes and consequences remains limited. We aim to assess the causes and consequences of AF via a bidirectional Mendelian randomization (MR) analysis.

Methods

We used publicly available genome-wide association study (GWAS) summary data, centralized and harmonized by an open GWAS database. We assessed the genetically predicted effects of 5048 exposures on risk of AF, and the genetically predicted effects of genetic liability to AF, on 10 308 outcomes via two-sample MR analysis. Multivariable MR analysis was further conducted to explore the comparative roles of identified risk factors.

Results

MR analysis suggested that 55 out of 5048 exposure traits, including four proteins, play a causal role in AF (P <1e-5 allowing for multiple comparisons). Multivariable analysis suggested that higher body mass index, height and systolic blood pressure as well as genetic liability to coronary artery diseases independently cause AF. Three out of the four proteins (DUSP13, TNFSF12 and IL6R) had a drug prioritizing score for atrial fibrillation of 0.26, 0.38 and 0.88, respectively (values closer to 1 indicating stronger evidence of the protein as a potential drug target). Genetic liability to AF was linked to a higher risk of cardio-embolic ischaemic stroke.

Conclusions

Our results suggest body mass index, height, systolic blood pressure and genetic liability to coronary artery disease are independent causal risk factors for AF. Several proteins, including DUSP13, IL-6R and TNFSF12, may have therapeutic potential for AF.

High levels of autoantibodies against apoB100 p210 are associated with lower incidence of atrial fibrillation in women

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) is associated with inflammation, both systemically and in the atrial tissue. Oxidized low-density lipoprotein (LDL) is increased in patients with AF and is suggested to be one of the molecules that drives inflammation. Autoantibodies against oxidized LDL and apolipoprotein B100, the protein component of LDL, are linked to atherosclerotic disease. However, whether these autoantibodies are associated with occurrence of AF is not known. We investigated autoantibodies against oxidized apolipoprotein B100 peptides and incidence of AF in a large population-based cohort.

METHODS

IgM and IgG against native and aldehyde-modified apoB100 peptides 210 (p210) and 45 were analyzed by enzyme-linked immunosorbent assay (ELISA) in 5169 individuals from the Malmö Diet and Cancer cohort.

RESULTS

Seven hundred sixty-nine incident AF cases were recorded during a follow-up of 21.3 years. Individuals with high levels of IgM against native p210 at baseline had a lower risk of developing AF; however, the association did not remain after adjustment for age and sex. Women had higher levels of IgM against native p210 than men (0.70 ± 0.22 AU vs. 0.63 ± 0.21 AU, p < 0.001). The association of IgM against native p210 and AF was significantly different between sexes (p for interaction = 0.024), where females with high IgM against p210 had a lower risk for incidence of AF (hazard ratio [95% confidence interval] 4th versus 1st quartile: 0.67 [0.49-0.91]; p = 0.01) after adjusting for risk factors and comorbidities.

CONCLUSION

These findings support an association of humoral autoimmunity with AF.

Mechanisms Underlying Antiarrhythmic Properties of Cardioprotective Agents Impacting Inflammation and Oxidative Stress

The prevention of cardiac life-threatening ventricular fibrillation and stroke-provoking atrial fibrillation remains a serious global clinical issue, with ongoing need for novel approaches. Numerous experimental and clinical studies suggest that oxidative stress and inflammation are deleterious to cardiovascular health, and can increase heart susceptibility to arrhythmias. It is quite interesting, however, that various cardio-protective compounds with antiarrhythmic properties are potent anti-oxidative and anti-inflammatory agents. These most likely target the pro-arrhythmia primary mechanisms. This review and literature-based analysis presents a realistic view of antiarrhythmic efficacy and the molecular mechanisms of current pharmaceuticals in clinical use. These include the sodium-glucose cotransporter-2 inhibitors used in diabetes treatment, statins in dyslipidemia and naturally protective omega-3 fatty acids. This approach supports the hypothesis that prevention or attenuation of oxidative and inflammatory stress can abolish pro-arrhythmic factors and the development of an arrhythmia substrate. This could prove a powerful tool of reducing cardiac arrhythmia burden.

Predictive value of lymphocyte-to-monocyte ratio in critically Ill patients with atrial fibrillation: A propensity score matching analysis

Background

Inflammation plays a key role in the initiation and progression of atrial fibrillation (AF). Lymphocyte‐to‐monocyte ratio (LMR) has been proved to be a reliable predictor of many inflammation‐associated diseases, but little data are available on the relationship between LMR and AF. We aimed to evaluate the predictive value of LMR in predicting all‐cause mortality among AF patients.

Methods

Data of patients diagnosed with AF were retrieved from the Medical Information Mart for Intensive Care‐III (MIMIC‐III) database. X‐tile analysis was used to calculate the optimal cutoff value for LMR. The Cox regression model was used to assess the association of LMR and 28‐day, 90‐day, and 1‐year mortality. Additionally, a propensity score matching (PSM) method was performed to minimize the impact of potential confounders.

Results

A total of 3567 patients hospitalized with AF were enrolled in this study. The X‐tile software indicated that the optimal cutoff value of LMR was 2.67. A total of 1127 pairs were generated, and all the covariates were well balanced after PSM. The Cox proportional‐hazards model showed that patients with the low LMR (≤2.67) had a higher 1‐year all‐cause mortality than those with the high LMR (>2.67) in the study cohort before PSM (HR = 1.640, 95% CI: 1.437–1.872, p < 0.001) and after PSM (HR = 1.279, 95% CI: 1.094–1.495, p = 0.002). The multivariable Cox regression analysis for 28‐day and 90‐day mortality yielded similar results.

Conclusions

The lower LMR (≤2.67) was associated with a higher risk of 28‐day, 90‐day, and 1‐year all‐cause mortality, which might serve as an independent predictor in AF patients.

New evidence of direct oral anticoagulation therapy on cardiac valve calcifications, renal preservation and inflammatory modulation

BACKGROUND

Rivaroxaban is a direct inhibitor of activated Factor X (FXa), an anti-inflammatory protein exerting a protective effect on the cardiac valve and vascular endothelium. We compare the effect of Warfarin and Rivaroxaban on inflammation biomarkers and their contribution to heart valve calcification progression and renal preservation in a population of atrial fibrillation (AF) patients with chronic kidney disease (CKD) stage 3b - 4.

METHODS

This was an observational, multicenter, prospective study enrolling 347 consecutive CKD stage 3b - 4 patients newly diagnosed with AF: 247 were treated with Rivaroxaban and 100 with Warfarin. Every 12 months, we measured creatinine levels and cardiac valve calcification via standard trans-thoracic echocardiogram, while plasma levels of inflammatory mediators were quantified by ELISA at baseline and after 24 months.

RESULTS

Over a follow-up of 24 months, long-term treatment with Rivaroxaban was associated with a significative reduction of cytokines. Patients treated with Rivaroxaban experienced a more frequent stabilization/regression of valve calcifications comparing with patients treated with Warfarin. Rivaroxaban use was related with an improvement in kidney function in 87.4% of patients, while in those treated with Warfarin was reported a worsening of renal clearance in 98% of cases. Patients taking Rivaroxaban experienced lower adverse events (3.2% vs 49%, p-value <0.001).

CONCLUSIONS

Our findings suggest that Rivaroxaban compared to Warfarin is associated with lower levels of serum markers of inflammation. The inhibition of FXa may exert an anti-inflammatory effect contributing to reduce the risk of cardiac valve calcification progression and worsening of renal function.

Hub microRNAs and genes in the development of atrial fibrillation identified by weighted gene co-expression network analysis

Co-expression network may contribute to better understanding molecular interaction patterns underlying cellular processes. To explore microRNAs (miRNAs) expression patterns correlated with AF, we performed weighted gene co-expression network analysis (WGCNA) based on the dataset GSE28954. Thereafter, we predicted target genes using experimentally verified databases (ENOCRI, miRTarBase, and Tarbase), and overlapped genes with differentially expressed genes (DEGs) from GSE79768 were identified as key genes. Integrated analysis of association between hub miRNAs and key genes was conducted to screen hub genes. In general, we identified 3 differentially expressed miRNAs (DEMs) and 320 DEGs, predominantly enriched in inflammation-related functional items. Two significant modules (red and blue) and hub miRNAs (hsa-miR-146b-5p and hsa-miR-378a-5p), which highly correlated with AF-related phenotype, were detected by WGCNA. By overlapping the DEGs and predicted target genes, 38 genes were screened out. Finally, 9 genes (i.e. ATP13A3, BMP2, CXCL1, GABPA, LIF, MAP3K8, NPY1R, S100A12, SLC16A2) located at the core region in the miRNA-gene interaction network were identified as hub genes. In conclusion, our study identified 2 hub miRNAs and 9 hub genes, which may improve the understanding of molecular mechanisms and help to reveal potential therapeutic targets against AF.

Altered synthesis of genes associated with short-chain fatty acids in the gut of patients with atrial fibrillation

BACKGROUND

The gut microbiota provides health benefits in humans by producing short-chain fatty acids (SCFAs), whose deficiency causes multiple disorders and inflammatory diseases. However, gut bacteria producing SCFAs in patients with atrial fibrillation (AF), an arrhythmia with increasing prevalence, have not been reported. To investigate major gut microbial organisms related to SCFA synthesis, SCFAs-associated KEGG orthologues (KOs), enzymatic genes, and potential producers were examined according to metagenomic data-mining in a northern Chinese cohort comprising 50 non-AF control and 50 AF patients.

RESULTS

Compared with non-AF controls, individuals with AF had marked differences in microbial genes involved in SCFA-related synthesis, including 125 KOs and 5 SCFAs-related enzymatic genes. Furthermore, there were 10 species that harbored SCFA-synthesis related enzymatic genes, and were markedly decreased in the gut of AF patients. Notably, discriminative features about SCFA-synthesis related function, including 8 KOs (K01752, K01738, K00175, K03737, K01006, K01653, K01647 and K15023), 4 genes (menI, tesB, yciA and CO dehydrogenase acetyl-CoA synthase complex) and 2 species (Coprococcus catus and Firmicutes bacterium CAG:103), were selected as key factors based on LASSO analysis. Furthermore, PLS-SEM analysis showed that 72.8 and 91.14 % of the overall effects on gut microbiota diversity and key species on AF, respectively, were mediated by the key KOs. Meanwhile, 46.31 % of the total effects of SCFA-synthesis related function on left atrial enlargement was mediated by hsCRP. Upon incorporation of clinical properties in AF, the KO score was still significantly associated with AF incidence (OR = 0.004, P = 0.001).

CONCLUSIONS

The current study revealed that dysbiotic gut microbiota in AF is coupled with disrupted SCFA-synthesis related genes, characterized by decreased abundances of KEGG orthologues, synthesis enzymatic genes and harboring species.

Electroimmunology and cardiac arrhythmia

Conduction disorders and arrhythmias remain difficult to treat and are increasingly prevalent owing to the increasing age and body mass of the general population, because both are risk factors for arrhythmia. Many of the underlying conditions that give rise to arrhythmia - including atrial fibrillation and ventricular arrhythmia, which frequently occur in patients with acute myocardial ischaemia or heart failure - can have an inflammatory component. In the past, inflammation was viewed mostly as an epiphenomenon associated with arrhythmia; however, the recently discovered inflammatory and non-canonical functions of cardiac immune cells indicate that leukocytes can be arrhythmogenic either by altering tissue composition or by interacting with cardiomyocytes; for example, by changing their phenotype or perhaps even by directly interfering with conduction. In this Review, we discuss the electrophysiological properties of leukocytes and how these cells relate to conduction in the heart. Given the thematic parallels, we also summarize the interactions between immune cells and neural systems that influence information transfer, extrapolating findings from the field of neuroscience to the heart and defining common themes. We aim to bridge the knowledge gap between electrophysiology and immunology, to promote conceptual connections between these two fields and to explore promising opportunities for future research.

Does Chronic Intestinal Inflammation Promote Atrial Fibrillation: A Mendelian Randomization Study With Populations of European Ancestry

Background: Inflammatory bowel disease (IBD), comprising ulcerative colitis (UC), and Crohn's disease (CD), has been reported to be associated with an increased risk of atrial fibrillation (AF). However, the causal role of the chronic intestinal inflammation (CII) in the development of AF remains controversial. We use Mendelian randomization (MR) analysis to explore the causal inference of CII on AF. Methods: A two-sample MR analysis was performed to estimate the potential causal effect of CII on AF. Statistical summaries for the associations between single nucleotide polymorphisms (SNPs) and phenotypes of CII were obtained from genome-wide association studies (GWAS) with cohorts of CD (n = 51,874), UC (n = 47,745), and IBD (n = 65,642) of European descent. The GWAS of 1,030,836 people of European ancestry, including 60,620 AF cases and 970,216 controls was collected to identify genetic variants underlying AF. The causal inference was estimated using the multiplicative random effects inverse-variance weighted method (IVW). The methods of MR-Egger, simple median, and weighted median were also employed to avoid the bias of pleiotropy effects. Results: Using three sets of SNPs (75 SNPs of CD, 60 SNPs of UC, and 95 SNPs of IBD), multiplicative random-effect IVW model estimated a universal null effect of CII on AF (CD: OR = 1.0059, 95% CI: 0.9900, 1.0220, p = 0.47; UC: OR = 1.0087, 95% CI: 0.9896, 1.0281, p = 0.38; IBD: OR = 1.0080, 95% CI: 0.9908, 1.0255, p = 0.37). Similar results were observed using the MR-Egger, simple median, weighted median methods. Conclusion: As opposing to the traditional observational studies, our two-sample MR analysis did not find enough evidence to support a causal role of either CD or UC in the development of AF.

Association of ACE2 variant rs4646188 with the risks of atrial fibrillation and cardioembolic stroke in Uygur patients with type 2 diabetes

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Type 2 diabetes (T2D) is an independent risk factor for AF. The cardioembolic stroke (CS) risk is increased when both conditions coexist. Whether angiotensin-converting enzyme 2 (ACE2) genetic variants predict increased risks AF and CS in Uygur patients with T2D remain elusive.

Methods

A total of 547 Uygur subjects (272 controls and 275 T2D patients) were recruited to the study from south Xinjiang. Eight ACE2 variants were identified by MassARRAY system.

Results

ACE2 rs2074192 (CC, adjusted RR = 2.55, 95% CI 1.35–4.80, P = 0.004), rs4240157 (CC + CT, adjusted RR = 2.26, 95% CI 1.27–4.04, P = 0.006) and rs4646188 (TT, adjusted RR = 2.37, 95% CI 1.16–4.86, P = 0.018) were associated with higher AF risk. ACE2 rs4240157 (CC + CT, adjusted RR = 2.68, 95% CI 1.36–5.27, P = 0.004) and rs4646188 (TT, adjusted RR = 2.56, 95% CI 1.06–6.20, P = 0.037) were further associated with higher CS risk. The 3 ACE2 variants were related to larger left atrial end-systolic diameter (LAD) (all P < 0.05), but not all of the 3 ACE2 variants were related to increased levels of serum sodium (rs4240157 and rs4646188, all P < 0.05), HsCRP (rs4240157 and rs4646188, all P < 0.05) as well as decreased serum potassium levels (rs2074192 and rs4646188, all P < 0.05). The 3 ACE2 variants exhibited heterogeneity on circulating RAAS activation. In particular, ACE2 rs4646188 was associated with higher levels of ACE (P = 0.017 and 0.037), Ang I (P = 0.002 and 0.001), Ang II (both P < 0.001) and ALD (P = 0.005 and 0.011).

Conclusion

These results indicated ACE2 rs4646188 was associated with increased risk of AF and CS among diabetic patients in Uygurs, which could be a promising genetic predisposition marker for early and personalized prevention strategies for the aforementioned clinical pathologies.

Evidence for Inflammation as a Driver of Atrial Fibrillation

Atrial fibrillation (AF) is one of the most common types of arrhythmias and increases cardiovascular morbidity and mortality. Current therapeutic approaches to AF that focus on rhythm control have high recurrence rates and no life prolongation value. While possible explanations include toxicity of current therapies, another likely explanation may be that current therapies do not address fundamental mechanisms of AF initiation and maintenance. Inflammation has been shown to affect signaling pathways that lead to the development of AF. This paper reviews the roles of inflammation in the occurrence, development, and mechanisms of AF and reviews the therapeutic implications of the correlation of inflammation and AF.

Serum N-Acetylneuraminic Acid Is Associated with Atrial Fibrillation and Left Atrial Enlargement

Purpose

Recent studies have indicated that N-acetylneuraminic acid (Neu5Ac) plays a key role in severe coronary artery diseases, involving RhoA signaling pathway activation, which is critically involved in cardiac fibrosis. There is convincing evidence from many studies that left atrium fibrosis is involved in the pathophysiology of AF. Therefore, we speculated that Neu5Ac may be associated with atrial fibrillation (AF) and involved in the development of AF. This study aims to investigate the clinical relationship between Neu5Ac and AF and left atrial enlargement.

Methods

Forty-five patients with AF (AF group) and forty-five patients with non-AF (control group) matched for age, sex, and hospitalization date were recruited for our study. Plasma concentrations of Neu5Ac from peripheral venous blood were analyzed using enzyme-linked immunosorbent assay (ELISA). The baseline characteristics, plasma level of Neu5Ac, and echocardiographic characteristics were evaluated.

Results

The plasma level of Neu5Ac was significantly higher in the AF group than in the control group (107.66 ± 47.50 vs 77.87 ± 39.09  ng/ml; P < 0.05); the left atrial diameters were positively correlated with the plasma Neu5Ac level (R = 0.255; P < 0.05). The plasma Neu5Ac level (R = 0.368; P < 0.05) and the left atrial diameters (R = 0.402; P < 0.05) were positively correlated with AF history times. Neu5Ac (odds ratio 1.018, 95% CI 1.003–1.032; P < 0.05) and the left atrial diameter (odds ratio 1.142, 95% CI 1.020–1.280; P < 0.05) were independent risk factors for AF in multivariate regression analysis.

Conclusions

Serum Neu5Ac is associated with atrial fibrillation, and the mechanism may involve left atrial enlargement.

Serum β2-Microglobulin Is Closely Associated With the Recurrence Risk and 3-Month Outcome of Acute Ischemic Stroke

Background and Purpose: Inflammation plays a significant role in the pathogenesis of acute ischemic stroke (AIS). The role of β2-microglobulin (β2M) as a potential initiator of the inflammatory response in AIS is unclear. The purpose of this study was to analyze the relationship of serum β2M with the recurrence risk and 3-month outcome of AIS.

Methods: A total of 205 patients with AIS were recruited, and their clinical and biochemical characteristics were collected. All patients were followed up for 3 months after stroke onset, and the occurrence of death or major disability at 3 months after onset was the outcome of interest in this study. We evaluated the association of serum β2M levels with the National Institute of Health Stroke Scale (NIHSS) scores, modified Rankin Scale (mRS) scores, and Essen Stroke Risk Score (ESRS) values in patients with AIS. Then, we used receiver operating curve analysis to calculate the optimal cutoff value for discriminating outcomes in patients with AIS and a binary logistic regression model to evaluate the risk factors for a poor outcome after AIS.

Results: Our results showed that serum β2M levels were significantly and positively correlated with ESRS values (r = 0.176, P < 0.001) and mRS scores (r = 0.402, P < 0.001), but the levels of β2M were not correlated with NIHSS scores (r = 0.080, P = 0.255) or with infarct volume (r = 0.013, P = 0.859). In a further study, we found that 121 patients (59.02%) had poor outcomes. The optimal β2M cutoff to predict the 3-month outcome of AIS in this study was 1.865 mg/l, and β2M was independently associated with a poor outcome at 3 months (OR = 3.325, 95% confidence interval: 1.089~10.148).

Conclusions: In conclusion, we inferred that serum β2M was positively associated with the recurrence risk and 3-month outcome of AIS, but it did not appear to be directly related to the severity of AIS or the size of the infarct at admission.

Uncovering Synergistic Mechanism of Chinese Herbal Medicine in the Treatment of Atrial Fibrillation with Obstructive Sleep Apnea Hypopnea Syndrome by Network Pharmacology

Paroxysmal atrial fibrillation (AF) combined with obstructive sleep apnea hypopnea syndrome (OSAHS) is very common in clinical practice. Traditional Chinese medicine (TCM) rule of regulating the liver based on psycho-cardiology shows satisfactory effectiveness in the treatment of paroxysmal AF combined with OSAHS. However, its underlying pharmacological mechanism has not yet been elucidated. This study applied network pharmacology to identify 94 active components in the six TCM liver-regulating herbs and 182 corresponding targets from several databases and comprehensive literature studies, as well as retrieved AF combined with OSAHS-related targets. Cytoscape software was adopted to construct the component-component target network and component-putative target-AF combined with OSAHS target network. Then, we obtained 38 putative therapeutic targets against AF combined with OSAHS. After the production of a putative therapeutic target interaction network, topological analysis was adopted to determine the core targets of TCM liver-regulating herbs in the treatment of paroxysmal AF combined with OSAHS. For all putative therapeutic targets, biological process analysis and pathway enrichment analysis were utilized to investigate the possible mechanism of TCM liver-regulating herbs in the treatment of paroxysmal AF combined with OSAHS. Mechanistically, it included positive regulation of nitric oxide biosynthetic process, aging, response to hypoxia, TNF signaling pathway, HIF-1 signaling pathway, PI3K-Akt signaling pathway, neuroactive ligand-receptor interaction, and calcium signaling pathway. Especially, six core targets of TCM liver-regulating herbs, namely, TNF, STAT3, AKT1, IL-6, TP53, and INS, were significant in the regulation of the above biological processes and pathways. This study demonstrates the multicomponent, multitarget, and multipathway feature of TCM liver-regulating herbs, provides an extensional foundation for further research, and facilitates the reasonable application of TCM liver-regulating herbs in treating paroxysmal AF combined with OSAHS.

Cognitive Function and Atrial Fibrillation: From the Strength of Relationship to the Dark Side of Prevention. Is There a Contribution from Sinus Rhythm Restoration and Maintenance?

Atrial fibrillation (AF) is the most common chronic cardiac arrhythmia with an increasing prevalence over time mainly because of population aging. It is well established that the presence of AF increases the risk of stroke, heart failure, sudden death, and cardiovascular morbidity. In the last two decades several reports have shown an association between AF and cognitive function, ranging from impairment to dementia. Ischemic stroke linked to AF is a well-known risk factor and predictor of cognitive decline. In this clinical scenario, the risk of stroke might be reduced by oral anticoagulation. However, recent data suggest that AF may be a predictor of cognitive impairment and dementia also in the absence of stroke. Cerebral hypoperfusion, reduced brain volume, microbleeds, white matter hyperintensity, neuroinflammation, and genetic factors have been considered as potential mechanisms involved in the pathogenesis of AF-related cognitive dysfunction. However, a cause-effect relationship remains still controversial. Consequently, no therapeutic strategies are available to prevent AF-related cognitive decline in stroke-free patients. This review will analyze the potential mechanisms leading to cognitive dysfunction in AF patients and examine the available data on the impact of a sinus rhythm restoration and maintenance strategy in reducing the risk of cognitive decline.

Serum beta2-microglobulin levels are highly associated with the risk of acute ischemic stroke

Inflammation is considered an important mechanism of cell death or survival after ischemic stroke. As an important marker of inflammation, the role of β2-microglobulin (β2M) in acute ischemic stroke is unclear. We investigated the relationship between serum β2M and the risk of acute ischemic stroke (AIS). Patients with AIS (202 cases), intracerebral hemorrhage (ICH, 41 cases), and healthy controls (253 cases) were recruited. Clinical and biochemical characteristics were collected. We used three binary logistic regression models to evaluate the correlation of β2M with the risk of AIS. Furthermore, we investigated the relationship between serum β2M and the National Institute of Health Stroke Scale (NIHSS) score, the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) subtypes, and the Essen Stroke Risk Score (ESRS) in patients with AIS. Our results showed that serum β2M levels in patients with AIS were much higher than those in patients with ICH and in the control subjects. Individuals with higher levels of β2M had higher odds of AIS. Moreover, serum β2M levels were significantly and positively correlated with ESRS. In addition, the levels of β2M were varied with different subgroups of AIS (TOAST classification). Serum β2M is highly associated with the risk of AIS.