Enhanced Cardiomyocyte NLRP3 Inflammasome Signaling Promotes Atrial Fibrillation

Identification of anti-inflammatory and anti-cancer compounds targeting the NF-κB-NLRP3 inflammasome pathway from a phytochemical library of the Sideritis genus

ETHNOBOTANICAL RELEVANCE

For centuries, the aerial parts of Sideritis species have been known for their medicinal properties as herbal teas. Although the antioxidant and anti-inflammatory properties of the genus have been widely documented, the underlying mechanisms are yet to be sufficiently clarified.

AIM OF THE STUDY

We investigated the anti-inflammatory and anticancer activities of phytochemicals of the Sideritis genus.

MATERIAL AND METHODS

Through literature mining, a chemical library containing 657 components of the Sideritis genus was formed. We studied these compounds for binding to NLRP3 and NF-κB proteins in silico by virtual drug screening and molecular docking, and in vitro by microscale thermophoresis (MST). Liquid chromatography-high-resolution mass spectrometry analysis (LC-HRMS) was performed in the Sideritis extracts. One of the identified compounds, verbascoside, was investigated for its cytotoxic activity by mining a panel of 49 tumor cell lines in the data repository of the National Cancer Institute (NCI, USA).

RESULTS

Virtual screening and molecular docking results highlighted two compounds targeting both proteins of interest, i.e., verbascoside (acteoside) and apigenin 7,4'-bis(trans-p-coumarate), as both had lowest binding energies of less than -10 kcal/mol. Using MST, we then verified that both compounds bound to the target proteins. Verbascoside bound to NLRP3 and NF-κB with Kd values of 0.67 ± 0.18 μM and 0.01 ± 0.08 μM, while apigenin 7,4'-bis(trans-p-coumarate) had Kd values of 4.60 ± 1.66 μM and 0.27 ± 0.75 μM, respectively. Verbascoside was abundant in the Sideritis extracts, according to LC-HRMS analysis. Since inflammation is strongly related to carcinogenesis, we investigated the anticancer activity of verbascoside in the second part of this study. We investigated the activity of verbascoside in 49 tumor cell lines of the NCI. Comparing its activity with 81 standard anticancer drugs revealed numerous interactions with DNA-damaging agents (alkylators, topoisomerase I/II inhibitors, antimetabolites), indicating that verbascoside may also affect the DNA of tumor cells. We further investigated the involvement of verbascoside in several main drug resistance mechanisms, i.e., ABC transporters, oncogenes, tumor suppressors, cellular proliferation rates, and other parameters. Except for the correlation to the mutational status of NRAS, no other significant relationships were found, indicating that verbascoside is not involved in most of the common drug resistance mechanisms. Two-dimensional cluster analysis-based heatmap generation of a proteomic profile from 40 out of 3171 proteins revealed a significant correlation between the expression of these proteins in 49 tumor cell lines, and the cellular response to verbascoside. This indicates that the presence of these proteins is a determinant for sensitivity or resistance to this natural product.

CONCLUSION

The database established here represents a valuable resource for the screening of bioactivites of the Sideritis genus. The experimental validation of the anti-inflammatory and cytotoxic activities of selected compounds proved that virtual drug screening and molecular docking are suitable tools for the identification of putative drug candidates. Verbascoside was among the top 10 compounds binding to two key anti-inflammatory proteins, NLRP3 and NF-kB. Additionally, data from the NCI indicate that verbascoside is not linked to main drug resistance mechanisms.

Associations between plasma caspase-1 levels and cardiovascular disease, with the mediating role of metabolic syndrome

AIMS

This study aimed to explore the association between plasma caspase-1 levels and cardiovascular disease (CVD), as well as the potential mediating role of metabolic syndrome (Mets) in the association.

METHODS

This study analyzed the UK Biobank Precision Proteomics Project (UKB-PPP), which detected plasma caspase-1 levels in participants. CVD was defined by ICD-9/ICD-10 codes. The Cox proportional hazards regression model was used to explore the hazard ratio (HR) of plasma caspase-1 levels with CVD. Mediation analysis was conducted to investigate the mediating effect of Mets and its components on this relationship.

RESULTS

This study included a total of 41,499 participants. Among them, 4869 (11.7 %) participants were documented to have developed CVD during a median follow-up of 13.6 years. In the fully adjusted model, compared with individuals in the lowest tertile of plasma caspase-1 levels, the highest tertile was significantly associated with an increased risk of CVD (HR = 1.11, 95 % CI, 1.04-1.19). Per one-unit Normalized Protein eXpression (NPX) increment in plasma caspase-1 concentrations was associated with a 6 % higher risk of CVD (p＜0.001). The mediating effect of Mets was the largest, at 17.5 %, with its components hypertension, central obesity, hypertriglyceridemia, hyperglycemia and dyslipidemia mediated the effects by 13.52 %, 9.72 %, 7.35 %, 4.63 % and 2.74 %, respectively.

CONCLUSIONS

Higher plasma caspase-1 levels were associated with a higher risk of CVD. This association may be partially mediated by Mets and its components, suggesting that caspase-1 may increase the risk of CVD by increasing the occurrence of Mets.

Human heart assembloids with autologous tissue-resident macrophages recreate physiological immuno-cardiac interactions

Interactions between the developing heart and the embryonic immune system are essential for proper cardiac development and maintaining homeostasis, with disruptions linked to various diseases. While human pluripotent stem cell (hPSC)-derived organoids are valuable models for studying human organ function, they often lack critical tissue-resident immune cells. Here, we introduce an advanced human heart assembloid model, termed hHMA (human heart-macrophage assembloid), which fully integrates autologous cardiac tissue- resident macrophages (MPs) with pre-existing human heart organoids (hHOs). Through multi-omic analyses, we confirmed that these MPs are phenotypically similar to embryonic cardiac tissue-resident MPs and remain viable in the assembloids over time. The inclusion of MPs significantly impacts hHMA development, influencing cardiac cellular composition, boosting cellular communication, remodeling the extracellular matrix, promoting ventricular morphogenesis, and enhancing sarcomeric maturation. Our findings indicate that MPs contribute to homeostasis via efferocytosis, integrate into the cardiomyocyte electrical system, and support catabolic metabolism. To demonstrate the versatility of this model, we developed a platform to study cardiac arrhythmias by chronic exposure to pro-inflammatory factors linked to arrhythmogenesis in clinical settings, successfully replicating key features of inflammasome-mediated atrial fibrillation. Overall, this work introduces a robust platform for examining the role of immune cells in cardiac development, disease mechanisms, and drug discovery, bridging the gap between in vitro models and human physiology. These findings offer insights into cardiogenesis and inflammation-driven heart disease, positioning the hHMA system as an invaluable tool for future cardiovascular research and therapeutic development.

Targeting the NLRP3 inflammasome signalling for the management of atrial fibrillation

Inflammatory signalling via the nod-like receptor (NLR) family pyrin domain-containing protein-3 (NLRP3) inflammasome has recently been implicated in the pathophysiology of atrial fibrillation (AF). However, the precise role of the NLRP3 inflammasome in various cardiac cell types is poorly understood. Targeting components or products of the inflammasome and preventing their proinflammatory consequences may constitute novel therapeutic treatment strategies for AF. In this review, we summarise the current understanding of the role of the inflammasome in AF pathogenesis. We first review the NLRP3 inflammasome pathway and inflammatory signalling in cardiomyocytes, (myo)fibroblasts and immune cells, such as neutrophils, macrophages and monocytes. Because numerous compounds targeting NLRP3 signalling are currently in preclinical development, or undergoing clinical evaluation for other indications than AF, we subsequently review known therapeutics, such as colchicine and canakinumab, targeting the NLRP3 inflammasome and evaluate their potential for treating AF.

Inhibition of TREM-1 ameliorates angiotensin II-induced atrial fibrillation by attenuating macrophage infiltration and inflammation through the PI3K/AKT/FoxO3a signaling pathway

Inflammation and infiltration of immune cells are intricately linked to the pathogenesis of atrial fibrillation (AF). Triggering receptor expressed on myeloid cells-1 (TREM-1), an enhancer of inflammation, is implicated in various cardiovascular disorders. However, the precise role and potential mechanisms of TREM-1 in the development of AF remain ambiguous. Atrial samples from patients with AF were used to assess the expression levels of TREM-1. An angiotensin II (Ang II)-induced AF mouse model was established to assess the functionality of TREM-1. Cardiac function and AF inducibility were assessed through echocardiography, programmed transvenous cardiac pacing, and atrial electrophysiological mapping. Peripheral blood and atrial inflammatory cells were assessed using flow cytometry. Using histology, bulk RNA sequencing, biochemical analyses, and cell cultures, the mechanistic role of TREM-1 in AF was elucidated. TREM-1 expression was upregulated and co-localized with macrophages in the atria of patients with AF. Pharmacological inhibition of TREM-1 decreased Ang II-induced atrial enlargement and electrical remodeling. TREM-1 inhibition also ameliorated Ang II-induced NLRP3 inflammasome activation, inflammatory factor release, atrial fibrosis, and macrophage infiltration. Transcriptomic analysis revealed that TREM-1 modulates Ang II-induced inflammation through the PI3K/AKT/FoxO3a signaling pathway. In vitro studies further supported these findings, demonstrating that TREM-1 activation exacerbates Ang II-induced inflammation, while overexpression of FoxO3a counteracts this effect. This study discovered the critical role of TREM-1 in the pathogenesis of AF and its underlying molecular mechanisms. Inhibition of TREM-1 provides a new therapeutic strategy for the treatment of AF.

Impeding Nucleotide-Binding Oligomerization Domain-Like Receptor 3 Inflammasome Ameliorates Cardiac Remodeling and Dysfunction in Obesity-Associated Cardiomyopathy

BACKGROUND

Inflammation and metabolic disturbances are key culprits in the pathogenesis of obesity-associated cardiomyopathy. The NLRP3 (nucleotide-binding oligomerization domain-like receptor 3) inflammasome mediates the release of the proinflammatory cytokines IL-1β (interleukin-1β) and IL-18 by activating caspase-1, which is strongly implicated in metabolic disturbances. We here sought to determine whether NLRP3 inflammasome inhibition could ameliorate obesity cardiomyopathy and if so, to further explore its underlying mechanisms.

METHODS AND RESULTS

Male mice were fed a high-fat diet for 24 weeks to induce obesity cardiomyopathy. MCC950 was used to inhibit NLRP3 inflammasome activation. Recombinant adeno-associated virus serotype 9 encoding TXNIP (thioredoxin-interacting protein) under cTnT (cardiac troponin T) promoter and the mitochondrial-targeted antioxidant MitoTEMPO were injected into obese mice to investigate the specific mechanism. To mimic obesity cardiomyopathy in vitro, neonatal rat ventricular myocytes transfected with the small interfering RNA against TXNIP were incubated with 400 μmol palmitic acid for 24 hours. NLRP3 inflammasome was significantly increased in obese hearts. NLRP3 inflammasome inhibition by NLRP3 deletion or MCC950 prevented obesity-induced cardiac systolic and diastolic dysfunction, myocardial hypertrophy and fibrosis, and excessive lipid accumulation in male mice. Conversely, TXNIP overexpression worsened obesity-associated cardiomyopathy. Similarly, MCC950 treatment or TXNIP knockdown reduced palmitic acid-induced NLRP3 inflammasome activation and lipid storage. Mechanistically, abnormal NF-κB (nuclear factor kappa B) pathway activation, increased mitochondrial reactive oxygen species, and elevated TXNIP levels led to excessive NLRP3 inflammasome activation.

CONCLUSIONS

Our study confirms that aberrant NLRP3 inflammasome activation in cardiomyocytes worsens obesity-associated cardiomyopathy and implicates inhibition of NLRP3 inflammasome as a potent therapeutic approach for obesity cardiomyopathy.

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.

Atrial Fibrillation in Heart Failure: Novel Insights, Challenges, and Treatment Opportunities

PURPOSE OF REVIEW

Atrial fibrillation and heart failure frequently co-exist. This review discusses the comorbidity of atrial fibrillation and heart failure, the bi-directional link between them, and the recent advances in the management of these co-existing diseases.

RECENT FINDINGS

Catheter ablation received a class 1 A recommendation for patients with AF and HF, after overwhelming evidence in heart failure with reduced ejection fraction and end-stage heart failure, while clinical trials are still lacking in patients with preserved ejection. Guideline-medical therapy of heart failure decreases the incidence of atrial fibrillation and the progression of atrial myopathy. Based on the current evidence, management of patients with both HF and AF should be include early optimization of comorbidity control, guideline-medical therapy for heart failure, and rhythm control preferentially through catheter ablation in properly selected patients.

Comparison of the Cecum Ligation and Puncture Method and the Intraperitoneal Lipopolysaccharide Injection Method for the Construction of a New-Onset Atrial Fibrillation Model of Sepsis

Background

New-onset atrial fibrillation (AF) in sepsis significantly impacted patient morbidity and mortality, yet the optimal animal model for studying this condition remains undetermined. This study aimed to establish a stable animal model for new-onset AF in sepsis and to explore the molecular mechanisms involved.

Methods

Forty-seven Sprague-Dawley rats were utilized, with the cecal ligation and puncture (CLP) group divided into 0.6 mm and 1.0 mm needle outer diameter subgroups, and the lipopolysaccharide (LPS) group into 5 mg/kg, 10 mg/kg, 15 mg/kg, and 20 mg/kg dosage subgroups. The incidence of new-onset AF and five-day mortality rates were compared to identify the most stable modeling conditions. Selected subgroups underwent further analysis, including cardiac ultrasound, electrophysiology, and pathological examinations. Inflammation-related molecular levels in the atrium were assessed using ELISA and Western blotting (WB).

Results

The intraperitoneal injection of 10 mg/kg LPS was identified as the most stable model for new-onset AF in sepsis, with significant findings including increased left atrial area and fibrosis, left ventricular pump dysfunction, uncoordinated ventricular wall motion, and impaired electrical impulse conduction. The effective atrial refractory period was markedly shorter, and susceptibility to AF was higher in the LPS group compared to the CLP group. Molecular analysis revealed elevated levels of NOD-like receptor protein 3(NLRP3) inflammasomes, apoptosis-associated speck-like protein containing a CARD(ASC), Caspase-1 p20 Elevated levels of three inflammation-related proteins and increased activity of the Sphingosine 1-phosphate/Sphingosine 1-phosphate Receptor 2(S1P/S1P2) signaling axis.

Conclusion

Intraperitoneal injection of 10 mg/kg of LPS can successfully construct a new-onset AF model in sepsis, and NLRP3 inflammatory vesicles mediated by the S1P/S1P2 signaling axis may promote new-onset AF in sepsis.

Role of NLRP3 Inflammasome in Heart Failure Patients Undergoing Cardiac Surgery as a Potential Determinant of Postoperative Atrial Fibrillation and Remodeling: Is SGLT2 Cotransporter Inhibition an Alternative for Cardioprotection?

In heart failure (HF) patients undergoing cardiac surgery, an increased activity of mechanisms related to cardiac remodeling may determine a higher risk of postoperative atrial fibrillation (POAF). Given that atrial fibrillation (AF) has a negative impact on the course and management of HF, including the need for anticoagulation therapy, identifying the factors associated with AF occurrence after cardiac surgery is crucial for the prognosis of these patients. POAF is thought to occur when various clinical and biochemical triggers act on susceptible cardiac tissue (first hit), with oxidative stress and inflammation during cardiopulmonary bypass (CPB) surgery being potential contributing factors (second hit). However, the molecular mechanisms involved in these processes remain poorly characterized. Recent research has shown that patients who later develop POAF often have pre-existing abnormalities in calcium handling and activation of NLRP3-inflammasome signaling in their atrial cardiomyocytes. These molecular changes may make cardiomyocytes more susceptible to spontaneous Ca2+-releases and subsequent arrhythmias, particularly when exposed to inflammatory mediators. Additionally, some clinical studies have linked POAF with elevated preoperative inflammatory markers, but there is a need for further research in order to better understand the impact of CPB surgery on local and systemic inflammation. This knowledge would make it possible to determine whether patients susceptible to POAF have pre-existing inflammatory conditions or cellular electrophysiological factors that make them more prone to developing AF and cardiac remodeling. In this context, the NLRP3 inflammasome, expressed in cardiomyocytes and cardiac fibroblasts, has been identified as playing a key role in the development of HF and AF, making patients with pre-existing HF with reduced ejection fraction (HFrEF) the focus of several clinical studies with interventions that act at this level. On the other hand, HFpEF has been linked to metabolic and non-ischemic risk factors, but more research is needed to better characterize the myocardial remodeling events associated with HFpEF. Therefore, since ventricular remodeling may differ between HFrEF and HFpEF, it is necessary to perform studies in both groups of patients due to their pathophysiological variations. Clinical evidence has shown that pharmacological therapies that are effective for HFrEF may not provide the same anti-remodeling benefits in HFpEF patients, particularly compared to traditional adrenergic and renin-angiotensin-aldosterone system inhibitors. On the other hand, there is growing interest in medications with pleiotropic or antioxidant/anti-inflammatory effects, such as sodium-glucose cotransporter 2 inhibitors (SGLT-2is). These drugs may offer anti-remodeling effects in both HFrEF and HFpEF by inhibiting pro-inflammatory, pro-oxidant, and NLRP3 signaling pathways and their mediators. The anti-inflammatory, antioxidant, and anti-remodeling effects of SGLT-2 i have progressively expanded from HFrEF and HFpEF to other forms of cardiac remodeling. However, these advances in research have not yet encompassed POAF despite its associations with inflammation, oxidative stress, and remodeling. Currently, the direct or indirect effects of NLRP3-dependent pathway inhibition on the occurrence of POAF have not been clinically assessed. However, given that NLRP3 pathway inhibition may also indirectly affect other pathways, such as inhibition of NF-kappaB or inhibition of matrix synthesis, which are strongly linked to POAF and cardiac remodeling, it is reasonable to hypothesize that this type of intervention could play a role in preventing these events.

Drug-Loaded Mesoporous Polydopamine Nanoparticles in Chitosan Hydrogels Enable Myocardial Infarction Repair through ROS Scavenging and Inhibition of Apoptosis

In this study, we synthesized mesoporous polydopamine nanoparticles (MPDA NPs) using an emulsion-induced interface assembly strategy and loaded epigallocatechin gallate (EGCG) into MPDA NPs via electrostatic attraction to form EGCG@MPDA NPs. In the post myocardial infarction (MI) environment, these interventions specifically aimed to eliminate reactive oxygen species (ROS) and facilitate the repair of MI. We further combined them with a thermosensitive chitosan (CS) hydrogel to construct an injectable composite hydrogel (EGCG@MPDA/CS hydrogel). Utilizing in vitro experiments, the EGCG@MPDA/CS hydrogel exhibited excellent ROS-scavenging ability of H9C2 cells under the oxidative stress environment and also could inhibit their apoptosis. The EGCG@MPDA/CS hydrogel significantly promoted left ventricular ejection fraction (LVEF) in infarcted rat models post injection for 28 days compared to the PBS group (51.25 ± 1.73% vs 29.31 ± 0.78%, P < 0.05). In comparison to the PBS group, histological analysis revealed a substantial increase in left ventricular (LV) wall thickness in the EGCG@MPDA/CS hydrogel group (from 0.58 ± 0.03 to 1.39 ± 1.11 mm, P < 0.05). This work presents a novel approach to enhance MI repair by employing the EGCG@MPDA/CS hydrogel. This hydrogel effectively reduces local oxidative stress by ROS and stimulates the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway.

Noise Exposure in the Workplace, Genetic Susceptibility, and Incidence of Atrial Fibrillation: A Prospective Cohort Study

BACKGROUND

No study explored the association of noise exposure in the workplace and genetic susceptibility with incidence of atrial fibrillation (AF). We aimed to assess the separate and joint relationship of noise exposure in the workplace and genetic susceptibility with the risk of AF.

METHODS AND RESULTS

We included 167 577 participants without AF at baseline in UK Biobank. Cox proportional hazards models were used to assess the separate and joint association of noise exposure in the workplace and genetic susceptibility with the risk of AF. During a median follow-up of 11.83 years, we observed 9355 AF cases. Compared with no noise exposure in the workplace, the hazard ratios (HRs) and were 1.08 (95% CI, 0.99-1.18) for noise exposure in the workplace of <1 year, 1.03 (95% CI, 0.95-1.12) for noise exposure in the workplace of around 1 to 5 years, and 1.08 (95% CI, 1.02-1.14) for noise exposure in the workplace of >5 years, respectively, after adjusting for potential confounders. Genetic risk was positively associated with AF, compared with low genetic risk (tertile 1), the HRs were 1.50 (95% CI, 1.41-1.59) for medium genetic risk (tertile 2) and 2.51 (95% CI, 2.38-2.65) for high genetic risk (tertile 3). However, no interaction between noise exposure in the workplace and genetic susceptibility was observed (P>0.05).

CONCLUSIONS

Long-term noise exposure in the workplace is positively associated with a higher incidence of AF regardless of genetic background.

Gene therapy for atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia in adults. Current limitations of pharmacological and ablative therapies motivate the development of novel therapies as next generation treatments for AF. The arrhythmia mechanisms creating and sustaining AF are key elements in the development of this novel treatment. Gene therapy provides a useful platform that allows us to regulate the mechanisms of interest using a suitable transgene(s), vector, and delivery method. Effective gene therapy strategies in the literature have targeted maladaptive electrical or structural remodeling that increase vulnerability to AF. In this review, we will summarize key elements of gene therapy for AF, including molecular targets, gene transfer vectors, atrial gene delivery and preclinical efficacy and toxicity testing. Recent advances and challenges in the field will be also discussed.

CHA2DS2-VASc Score as Predictor of New-Onset Atrial Fibrillation and Mortality in Critical COVID-19 Patients

BACKGROUND

Pre-existing and new-onset atrial fibrillation (NOAF) is a common arrhythmia in COVID-19 patients and is related to increased mortality. CHA2DS2-VASc score was initially developed to evaluate thromboembolic risk in patients with AF. Moreover, it predicted adverse outcomes in other clinical conditions, including SARS-CoV-2 infection. We aimed to evaluate the association of CHA2DS2-VASc with NOAF, ICU length of stay (LOS) and mortality in critically ill COVID-19 patients. We also examined the relationship of NOAF with mortality. We reviewed the literature to describe the link between cardiovascular risk factors and inflammatory response of severe COVID-19.

METHODS AND RESULTS

We retrospectively studied 163 COVID-19 patients admitted to a level 3 general ICU from March 2020 to April 2022. Patients were of advanced age (median 64 years, IQR 56.5-71) and the majority of them were male (67.5%). Regarding NOAF, we excluded 12 patients with AF history. In this group, CHA2DS2VASc score was significantly elevated (3 IQR (1-4) versus 1 IQR (1-2.75), p = 0.003). Specifically, three components of CHA2DS2VASc were notably increased: age (p < 0.001), arterial hypertension (p = 0.042) and stroke (p = 0.047). ICU mortality was raised in the NOAF group [75.8% versus 34.8%, p < 0.001 OR 5.87, 95% CI (2.43, 14.17)]. This was significant even after adjusting for ICU clinical scores (APACHE II and SOFA). About mortality in the entire sample, survivors were younger (p = 0.001). Non-survivors had greater APACHE II (p = 0.04) and SOFA (p = 0.033) scores. CHA2DS2VASc score was positively associated with mortality [p = 0.031, OR 1.28, 95% CI (1.03, 1.6)]. ICU length of stay was associated with mortality (p = 0.016) but not with CHA2DS2VASc score (p = 0.842).

CONCLUSIONS

NOAF and CHA2DS2VASc score were associated with higher mortality in COVID-19 ICU patients. CHA2DS2VASc score was also associated with NOAF but not with ICU LOS.

Molecular mechanisms involved in therapeutic effects of natural compounds against cisplatin-induced cardiotoxicity: a review

Cisplatin is a widely used chemotherapeutic agent for the treatment of various cancers. However, the clinical use of cisplatin is limited by its cardiotoxic side effects. The primary mechanisms implicated in this cardiotoxicity include mitochondrial dysfunction, oxidative stress, inflammation, and apoptotic. Numerous natural compounds (NCs) have been introduced as promising protective factors against cisplatin-mediated cardiac damage. The current review summarized the potential of various NCs as cardioprotective agents at the molecular levels. These compounds exhibited potent antioxidant and anti-inflammatory effects by interaction with the PI3K/AKT, AMPK, Nrf2, NF-κB, and NLRP3/caspase-1/GSDMD pathways. Generally, the modulation of these signaling pathways by NCs represents a promising strategy for improving the therapeutic index of cisplatin by reducing its cardiac side effects.

Rectifying METTL4-Mediated N6-Methyladenine Excess in Mitochondrial DNA Alleviates Heart Failure

BACKGROUND

Myocardial mitochondrial dysfunction underpins the pathogenesis of heart failure (HF), yet therapeutic options to restore myocardial mitochondrial function are scarce. Epigenetic modifications of mitochondrial DNA (mtDNA), such as methylation, play a pivotal role in modulating mitochondrial homeostasis. However, their involvement in HF remains unclear.

METHODS

Experimental HF models were established through continuous angiotensin II and phenylephrine (AngII/PE) infusion or prolonged myocardial ischemia/reperfusion injury. The landscape of N6-methyladenine (6mA) methylation within failing cardiomyocyte mtDNA was characterized using high-resolution mass spectrometry and methylated DNA immunoprecipitation sequencing. A tamoxifen-inducible cardiomyocyte-specific Mettl4 knockout mouse model and adeno-associated virus vectors designed for cardiomyocyte-targeted manipulation of METTL4 (methyltransferase-like protein 4) expression were used to ascertain the role of mtDNA 6mA and its methyltransferase METTL4 in HF.

RESULTS

METTL4 was predominantly localized within adult cardiomyocyte mitochondria. 6mA modifications were significantly more abundant in mtDNA than in nuclear DNA. Postnatal cardiomyocyte maturation presented with a reduction in 6mA levels within mtDNA, coinciding with a decrease in METTL4 expression. However, an increase in both mtDNA 6mA level and METTL4 expression was observed in failing adult cardiomyocytes, suggesting a shift toward a neonatal-like state. METTL4 preferentially targeted mtDNA promoter regions, which resulted in interference with transcription initiation complex assembly, mtDNA transcriptional stalling, and ultimately mitochondrial dysfunction. Amplifying cardiomyocyte mtDNA 6mA through METTL4 overexpression led to spontaneous mitochondrial dysfunction and HF phenotypes. The transcription factor p53 was identified as a direct regulator of METTL4 transcription in response to HF-provoking stress, thereby revealing a stress-responsive mechanism that controls METTL4 expression and mtDNA 6mA. Cardiomyocyte-specific deletion of the Mettl4 gene eliminated mtDNA 6mA excess, preserved mitochondrial function, and mitigated the development of HF upon continuous infusion of AngII/PE. In addition, specific silencing of METTL4 in cardiomyocytes restored mitochondrial function and offered therapeutic relief in mice with preexisting HF, irrespective of whether the condition was induced by AngII/PE infusion or myocardial ischemia/reperfusion injury.

CONCLUSIONS

Our findings identify a pivotal role of cardiomyocyte mtDNA 6mA and the corresponding methyltransferase, METTL4, in the pathogenesis of mitochondrial dysfunction and HF. Targeted suppression of METTL4 to rectify mtDNA 6mA excess emerges as a promising strategy for developing mitochondria-focused HF interventions.

CALCOCO2 prevents AngII-induced atrial remodeling by regulating the interaction between mitophagy and mitochondrial stress

BACKGROUND

The biological functions of mitochondrial complexes are closely related to the development of atrial fibrillation (AF). Calcium binding and coiled-coil domain 2 (CALCOCO2) is a novel and specific receptor for mitophagy; however, its function in AF remains unknown. Therefore, this study aimed to investigate the role and molecular mechanisms of CALCOCO2 in AF, especially its regulatory mechanism in mitophagy and mitochondrial stress.

METHODS

Mice and HL-1 cells were treated with AngII to establish in vitro and in vivo AF models. Additionally, we examined the effect of CALCOCO2 or DAP3 Binding Cell Death Enhancer 1 (DELE1) overexpression on mitophagy and mitochondrial stress in AF models. To investigate the role of mitophagy in the regulatory effects of CALCOCO2 in AF, HL-1 cells were treated with chloroquine, a mitophagy inhibitor. Moreover, mitochondrial parameters were examined using specific fluorescent probes, transmission electron microscopy, western blotting, immunohistochemistry, and confocal microscopy.

RESULTS

AngII severely impaired the normal morphology and function of mitochondria; inhibited mitophagy; promoted atrial mitochondrial stress, fibrosis, and oxidative stress; and accelerated the progression of atrial remodeling in atrial myocytes. However, CALCOCO2 overexpression reversed/ameliorated these AF-induced changes. Additionally, CALCOCO2 overexpression restored mitochondrial homeostasis in atrial muscle by activating mitophagy and ameliorating mitochondrial stress. Mechanistically, DELE1 overexpression increased mitochondrial reactive oxygen species level and the expression of mitochondrial stress proteins (HRI, eIF2α, and ATF4) even in CALCOCO2-expressing in vitro AF models..

CONCLUSIONS

CALCOCO2 may serve as a potential target for AF therapy to prevent or reverse the progression of atrial remodeling by regulating mitophagy and DELE1-mediated mitochondrial stress.

Identification of the optimal reference genes for atrial fibrillation model established by iPSC-derived atrial myocytes

BACKGROUND

Atrial fibrillation (AF) stands as a prevalent and detrimental arrhythmic disorder, characterized by intricate pathophysiological mechanisms. The availability of reliable and reproducible AF models is pivotal in unraveling the underlying mechanisms of this complex condition. Unfortunately, the researchers are still confronted with the absence of consistent in vitro AF models, hindering progress in this crucial area of research.

METHODS

Human induced pluripotent stem cells derived atrial myocytes (hiPSC-AMs) were generated based on the GiWi methods and were verified by whole-cell patch clamp, immunofluorescent staining, and flow cytometry. Then hiPSC-AMs were employed to establish the AF model by HS. Whole-cell patch clamp technique and calcium imaging were used to identify the AF model. The stability of 29 reference genes was evaluated using delta-Ct, GeNorm, NormFinder, and BestKeeper algorithms; RESULTS: HiPSC-AMs displayed atrial myocyte action potentials and expressed the atrial-specific protein MLC-2 A and NR2F2, about 70% of the cardiomyocytes were MLC-2 A positive. After HS, hiPSC-AMs showed a significant increase in beating frequency, a shortened action potential duration, and increased calcium transient frequency. Of the 29 candidate genes, the top five most stably ranked genes were ABL1, RPL37A, POP4, RPL30, and EIF2B1. After normalization using ABL1, KCNJ2 was significantly upregulated in the AF model; Conclusions: In the hiPSC-AMs AF model established by HS, ABL1 provides greater normalization efficiency than commonly used GAPDH.

[Pathogenesis and potential diagnostic biomarkers of atrial fibrillation in Chinese population: a study based on bioinfor-matics]

OBJECTIVES

To explore the pathogenesis and potential biomarkers of atrial fibrillation based on bioinformatics.

METHODS

Differentially expressed genes and module genes related to atrial fibrillation were obtained from GSE41177 and GSE79768 datasets (Chinese-origin tissue samples) through differential expression analysis and weighted gene co-expression network analysis. Candidate hub genes were obtained by taking intersections, and hub genes were obtained after gender stratification. Subsequently, functional enrichment analysis and immune infiltration analysis were performed. Four machine learning models were constructed based on the hub genes, and the optimal model was selected to construct a prediction nomogram. The prediction ability of the nomogram was verified using calibration curves and decision curves. Finally, potential therapeutic drugs for atrial fibrillation were screened from the DGIdb database.

RESULTS

A total of 67 differentially expressed genes and 65 module genes related to atrial fibrillation were identified. Functional enrichment analysis indicated that the pathogenesis of atrial fibrillation was closely related to inflammatory response, immune response, and immune and infectious diseases. Four common hub genes (TYROBP, FCER1G, EVI2B and SOD2), and two genes specifically expressed in male (PILRA and SLC35G3) and female (HLA-DRA and GATP) patients with atrial fibrillation were obtained after gender-segregated screening. The extreme gradient boosting model had satisfactory diagnostic efficiency, and the nomogram constructed based on the hub genes, male significant variables (PILRA, SLC35G3 and SOD2), and female significant variables (FCER1G, SOD2 and TYROBP) had satisfactory predictive ability. Immune infiltration analysis demonstrated a disturbed immune infiltration microenvironment in atrial fibrillation with a higher abundance of plasma cells, neutrophils, and γδT cells, with a higher abundance of neutrophils in males and resting mast cells in females. Two potential drugs for the treatment of atrial fibrillation, valproic acid and methotrexate, were obtained by database and literature screening.

CONCLUSIONS

The pathogenesis of atrial fibrillation is closely related to inflammation and immune response, and the microenvironment of immune cell infiltration of cardiomyocytes in the atrial tissue of patients with atrial fibrillation is disordered. TYROBP, FCER1G, EVI2B and SOD2 serve as potential diagnostic biomarkers of atrial fibrillation; PILRA and SLC35G3 serve as potential specific diagnostic biomarkers of atrial fibrillation in the male population, which can effectively predict the risk of atrial fibrillation development and are also potential targets for the treatment of atrial fibrillation.

Translation of pathophysiological mechanisms of atrial fibrosis into new diagnostic and therapeutic approaches

Atrial fibrosis is one of the main manifestations of atrial cardiomyopathy, an array of electrical, mechanical and structural alterations associated with atrial fibrillation (AF), stroke and heart failure. Atrial fibrosis can be both a cause and a consequence of AF and, once present, it accelerates the progression of AF. The pathophysiological mechanisms leading to atrial fibrosis are diverse and include stretch-induced activation of fibroblasts, systemic inflammatory processes, activation of coagulation factors and fibrofatty infiltrations. Importantly, atrial fibrosis can occur in different forms, such as reactive and replacement fibrosis. The diversity of atrial fibrosis mechanisms and patterns depends on sex, age and comorbidity profile, hampering the development of therapeutic strategies. In addition, the presence and severity of comorbidities often change over time, potentially causing temporal changes in the mechanisms underlying atrial fibrosis development. This Review summarizes the latest knowledge on the molecular and cellular mechanisms of atrial fibrosis, its association with comorbidities and the sex-related differences. We describe how the various patterns of atrial fibrosis translate into electrophysiological mechanisms that promote AF, and critically appraise the clinical applicability and limitations of diagnostic tools to quantify atrial fibrosis. Finally, we provide an overview of the newest therapeutic interventions under development and discuss relevant knowledge gaps related to the association between clinical manifestations and pathological mechanisms of atrial fibrosis and to the translation of this knowledge to a clinical setting.

m6A reader YTHDF2 governs the onset of atrial fibrillation by modulating Cacna1c translation

Atrial fibrillation (AF) is the most common arrhythmia, which is tightly associated with the abnormal expression and function of ion channels in the atrial cardiomyocytes. N6-methyladenosine (m6A), a widespread chemical modification in eukaryotic mRNA, is known to play a significant regulatory role in the pathogenesis of heart disease. However, the significance of m6A regulatory proteins in the onset of AF remains unclear. Here, we demonstrate that the m6A reader protein YTHDF2 regulates atrial electrical remodeling and AF onset by modulating the Cav1.2 expression. Firstly, YTHDF2 expression was selectively upregulated in rat atrial cardiomyocytes with AF. Secondly, YTHDF2 knockout reduced AF susceptibility in mice. Thirdly, the knockout of YTHDF2 increased Cav1.2 protein levels in an m6A-in-dependent manner, ultimately prolonging the atrial myocardial refractory period, a critical electrophysiological substrate for the onset of AF. Fourthly, the N-terminal domain of YTHDF2 was identified as critical for Cacna1c mRNA translation regulation. Overall, our findings unveil that YTHDF2 can alter Cav1.2 protein expression in an m6A-independent manner, thereby facilitating the onset of AF. Our study suggests that YTHDF2 may be a potential intervention target for AF.

The effect of macrophage-cardiomyocyte interactions on cardiovascular diseases and development of potential drugs

The interaction between macrophages and cardiomyocytes plays an important role not only in maintaining cardiac homeostasis, but also in the development of many cardiovascular diseases (CVDs), such as myocardial infarction (MI) and heart failure (HF). In addition to supporting cardiomyocytes, macrophages and cardiomyocytes have a close and complex relationship. By studying their cross-talk, we can better understand novel mechanisms and target pathogenic mechanisms, and improve the treatment of CVDs. We review macrophage-cardiomyocyte communication through connexin 43 (Cx43)-containing gap junctions (GJs) directly, secreted protein factors indirectly, and discuss the implications of these interactions in cardiac homeostasis and the development of various CVDs, including MI, HF, arrhythmia, cardiac fibrosis and myocarditis. In this section, we review various drugs that work by modulating cytokines or other proteins to reduce inflammation in CVDs. The clinical findings from targeting inflammation in CVDs are also discussed. Additionally, we examine the challenges and opportunities for improving our understanding of macrophage-cardiomyocyte coupling as it relates to pathophysiological disease processes, extending our research scope, and helping identify new molecular targets and improve the effectiveness of existing therapies.

Metabolic remodelling in atrial fibrillation: manifestations, mechanisms and clinical implications

Atrial fibrillation (AF) is a continually growing health-care burden that often presents together with metabolic disorders, including diabetes mellitus and obesity. Current treatments often fall short of preventing AF and its adverse outcomes. Accumulating evidence suggests that metabolic disturbances can promote the development of AF through structural and electrophysiological remodelling, but the underlying mechanisms that predispose an individual to AF are aetiology-dependent, thus emphasizing the need for tailored therapeutic strategies to treat AF that target an individual's metabolic profile. AF itself can induce changes in glucose, lipid and ketone metabolism, mitochondrial function and myofibrillar energetics (as part of a process referred to as 'metabolic remodelling'), which can all contribute to atrial dysfunction. In this Review, we discuss our current understanding of AF in the setting of metabolic disorders, as well as changes in atrial metabolism that are relevant to the development of AF. We also describe the potential of available and emerging treatment strategies to target metabolic remodelling in the setting of AF and highlight key questions and challenges that need to be addressed to improve outcomes in these patients.

Early inhibition of the ATM/p53 pathway reduces the susceptibility to atrial fibrillation and atrial remodeling following acute myocardial infarction

Atrial fibrillation (AF) emerges as a critical complication following acute myocardial infarction (AMI) and is associated with a significant increased risk of heart failure, stroke and mortality. Ataxia telangiectasia mutated (ATM), a key player in DNA damage repair (DDR), has been implicated in multiple cardiovascular conditions, however, its involvement in the development of AF following AMI remains unexplored. This study seeks to clarify the contribution of the ATM/p53 pathway in the onset of AF post-AMI and to investigate the underlying mechanisms. The rat model of AMI was established by ligating left anterior descending coronary artery in the presence or absence of Ku55933 (an ATM kinase inhibitor, 5 mg/kg/d) treatment. Rats receiving Ku55933 were further divided into the early administration group (administered on days 1, 2, 4, and 7 post-AMI) and the late administration group (administered on days 8, 9, 11 and 14 post-AMI). RNA-sequencing was performed 14 days post-operation. In vitro, H2O2-challenged HL-1 atrial muscle cells were utilized to evaluate the potential effects of different ATM inhibition schemes, including earlier, middle, and late periods of intervention. Fourteen days post-AMI injury, the animals exhibited significantly increased AF inducibility, exacerbated atrial electrical/structural remodeling, reduced ventricular function and exacerbated atrial DNA damage, as evidenced by enhanced ATM/p53 signaling as well as γH2AX level. These effects were partially consistent with the enrichment results of bioinformatics analysis. Notably, the deleterious effects were ameliorated by early, but not late, administration of Ku55933. Mechanistically, inhibition of ATM signaling successfully suppressed atrial NLRP3 inflammasome-mediated pyroptotic pathway. Additionally, the results were validated in the in vitro experiments demonstrating that early inhibition of Ku55933 not only attenuated cellular ATM/p53 signaling, but also mitigated inflammatory response by reducing NLRP3 activation. Collectively, hyperactivation of ATM/p53 contributed to the pathogenesis of AF following AMI. Early intervention with ATM inhibitors substantially mitigated AF susceptibility and atrial electrical/structural remodeling, highlighting a novel therapeutic avenue against cardiac arrhythmia following AMI.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.

Aging-associated atrial fibrillation: A comprehensive review focusing on the potential mechanisms

Atrial fibrillation (AF) has been receiving a lot of attention from scientists and clinicians because it is an extremely common clinical condition. Due to its special hemodynamic changes, AF has a high rate of disability and mortality. So far, although AF has some therapeutic means, it is still an incurable disease because of its complex risk factors and pathophysiologic mechanisms, which is a difficult problem for global public health. Age is an important independent risk factor for AF, and the incidence of AF increases with age. To date, there is no comprehensive review on aging-associated AF. In this review, we systematically discuss the pathophysiologic evidence for aging-associated AF, and in particular explore the pathophysiologic mechanisms of mitochondrial dysfunction, telomere attrition, cellular senescence, disabled macroautophagy, and gut dysbiosis involved in recent studies with aging-associated AF. We hope that by exploring the various dimensions of aging-associated AF, we can better understand the specific relationship between age and AF, which may be crucial for innovative treatments of aging-associated AF.

Thrombin receptor PAR4 cross-activates the tyrosine kinase c-met in atrial cardiomyocytes

Thrombin supports coagulation-independent inflammation via protease-activated receptors (PAR). PAR4 is specifically increased in obese human atria, correlating with NLRP3 inflammasome activation. PAR4-mediated NLRP3 inflammasome activation in atrial cardiomyocytes is not known, nor have signaling partners been identified. Thrombin transactivates the hepatocyte growth factor receptor in some cancer cells, so we examined PAR4/c-met cross-talk in atrial cardiomyocytes and its possible significance in obesity. Cardiomyocytes from right atrial appendages (RAA) of obese patients expressed more PAR1 and PAR4 compared to non-obese. In HL-1 atrial cardiomyocytes, thrombin induced caspase-1 auto-activation and IL-1β maturation; IL-1β secretion was evoked by PAR4-activating peptide (AP), but not PAR1-AP. PAR4-AP additionally increased phosphorylated CaMKII-Thr287, mTOR-Ser2481, and Akt-Ser473 while suppressing AMPK-Thr172 phosphorylation. Total kinase levels were largely unaltered. PAR4AP rapidly increased phosphorylated c-met in HL-1 cells and over time also transcriptionally upregulated c-met. The c-met inhibitor SGX-523 abrogated the effects of PAR4-AP on CaMKII/AKT/mTOR phosphorylation but did not affect PAR4-stimulated IL-1β production. Obese human RAA contained more IL-1β, phospho-c-met, and phospho-mTOR than non-obese RAA; CamKII phosphorylation was not modified. Atria from high-fat diet (HFD) versus chow-fed mice also contained more IL-1β, together with higher myeloperoxidase activity, Acta2 mRNA total and phosphorylated c-met; these increases were blunted in PAR4-/- HFD-fed mice. Thrombin cross-activates c-met via PAR4 in atrial cardiomyocytes. Transactivated c-met contributes partially to PAR4-mediated signaling, but NLRP3 inflammasome activation appears to be largely independent of c-met. Abundance of PAR4 and activated c-met increases with obesity, providing therapeutic targets for management of adiposity-driven AF.

Colchicine for the treatment of the spectrum of cardiovascular diseases: current evidence and ongoing perspectives

Colchicine is one of the oldest drugs in medicine. Traditionally used to treat and prevent gouty attacks, it has been introduced into cardiovascular medicine for the treatment and prevention of pericarditis, starting from the positive experience in the treatment and prevention of polyserositis in familial mediterranean fever. Colchicine is a lipophilic drug that enters the cells and is eliminated by glycoprotein P. As granulocytes are lacking in this protein, colchicine is able to concentrate in these cells, exerting a substantial anti-inflammatory action, even with low oral doses. As these cells may trigger acute cardiovascular events, colchicine has been shown to be efficacious and safe to prevent acute coronary syndromes and ischemic stroke with an efficacy comparable to more established treatments, such as antiplatelet agents and statins. On this basis, colchicine seems a promising, efficacious, well tolerated, and cheap option for the prevention of several cardiovascular events, and it may become an additional pillar in the pharmacologic treatment of cardiovascular diseases.

Relationship between sodium-glucose cotransporter 2 inhibitors and atrial fibrillation recurrence after pulmonary vein isolation in patients with type 2 diabetes and persistent atrial fibrillation

BACKGROUND

The impact of sodium-glucose cotransporter 2 (SGLT2) inhibitors on the postoperative recurrence of atrial fibrillation (AF) in patients with persistent AF undergoing an initial radiofrequency ablation is not yet established. The objective of this study is to assess the impact of SGLT2 inhibitors on the recurrence of AF after radiofrequency ablation in patients with type 2 diabetes complicated persistent AF.

METHODS

A total of 182 patients with type 2 diabetes and persistent AF, who underwent their first radiofrequency ablation for AF at our center, were enrolled and divided into two groups: the SGLT2 inhibitor group and the non-SGLT2 inhibitor group. The main outcome of the follow-up was the postoperative recurrence of AF.

RESULTS

A total of 49 participants experienced AF recurrence. The use of SGLT2 inhibitors in patients with type 2 diabetes who underwent AF ablation was associated with a significantly lower risk of AF recurrence (adjusted hazard ratio: 0.65; 95% confidence interval: 0.28-0.83; p < .01).

CONCLUSIONS

The use of SGLT2 inhibitors is associated with a decreased risk of arrhythmia recurrence after AF ablation in patients with type 2 diabetes complicated with persistent AF.

Investigative agents for atrial fibrillation: agonists and stimulants, progress and expectations

INTRODUCTION

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Its prevalence has increased due to worldwide populations that are aging in combination with the growing incidence of risk factors associated. Recent advances in our understanding of AF pathophysiology and the identification of nodal players involved in AF-promoting atrial remodeling highlights potential opportunities for new therapeutic approaches.

AREAS COVERED

This detailed review summarizes recent developments in the field antiarrhythmic drugs in the field AF.

EXPERT OPINION

The current situation is far than optimal. Despite clear unmet needs in drug development in the field of AF treatment, the current development of new drugs is absent. The need for a molecule with absence of cardiac and non-cardiac toxicity in the short and long term is a limitation in the field. Improvement in the understanding of AF genetics, pathophysiology, molecular alterations, big data and artificial intelligence with the objective to provide a personalized AF treatment will be the cornerstone of AF treatment in the coming years.

Atrial fibrillation in cancer, anticancer therapies, and underlying mechanisms

Atrial fibrillation (AF) is a common arrhythmic complication in cancer patients and can be exacerbated by traditional cytotoxic and targeted anticancer therapies. Increased incidence of AF in cancer patients is independent of confounding factors, including preexisting myocardial arrhythmogenic substrates, type of cancer, or cancer stage. Mechanistically, AF is characterized by fast unsynchronized atrial contractions with rapid ventricular response, which impairs ventricular filling and results in various symptoms such as fatigue, chest pain, and shortness of breath. Due to increased blood stasis, a consequence of both cancer and AF, concern for stroke increases in this patient population. To compound matters, cardiotoxic anticancer therapies themselves promote AF; thereby exacerbating AF morbidity and mortality in cancer patients. In this review, we examine the relationship between AF, cancer, and cardiotoxic anticancer therapies with a focus on the shared molecular and electrophysiological mechanisms linking these disease processes. We also explore the potential role of sodium-glucose co-transporter 2 inhibitors (SGLT2i) in the management of anticancer-therapy-induced AF.

Modern Instrumental Methods of Diagnostics and Risk Assessment of Developing Antitumor Therapy Cardiovasculotoxicity

The most important component of cardio-oncology is the assessment of the risk of development and diagnosis of cardiovascular toxicity of the antitumor therapy, the detection of which is largely based on visualization of the cardiovascular system. The article addresses up-to-date methods of non-invasive visualization of the heart and blood vessels, according to the 2022 European Society of Cardiology Clinical Guidelines on cardio-oncology. Also, the article discusses promising cardiovascular imaging techniques that are not yet included in the guidelines: assessment of coronary calcium using multislice computed tomography and positron emission computed tomography with 18F-labeled 2-deoxy-2-fluoro-d-glucose.

Atrial cardiomyopathy revisited-evolution of a concept: a clinical consensus statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asian Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS)

AIMS

The concept of "atrial cardiomyopathy" (AtCM) had been percolating through the literature since its first mention in 1972. Since then, publications using the term were sporadic until the decision was made to convene an expert working group with representation from four multinational arrhythmia organizations to prepare a consensus document on atrial cardiomyopathy in 2016 (EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication). Subsequently, publications on AtCM have increased progressively.

METHODS AND RESULTS

The present consensus document elaborates the 2016 AtCM document further to implement a simple AtCM staging system (AtCM stages 1-3) by integrating biomarkers, atrial geometry, and electrophysiological changes. However, the proposed AtCM staging needs clinical validation. Importantly, it is clearly stated that the presence of AtCM might serve as a substrate for the development of atrial fibrillation (AF) and AF may accelerates AtCM substantially, but AtCM per se needs to be viewed as a separate entity.

CONCLUSION

Thus, the present document serves as a clinical consensus statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asian Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS) to contribute to the evolution of the AtCM concept.

Sepsis-Induced Coagulopathy Score is Associated with an Increased Risk of New-Onset Atrial Fibrillation in Septic Patients: A Two-Centered Retrospective Study

Purpose

New-onset atrial fibrillation (NOAF) and sepsis-induced coagulopathy (SIC) are severe complications in septic patients. However, the relationship between NOAF and SIC score has not been clearly defined. This study aims to investigate the association between SIC score and NOAF, as well as their effect on mortality in sepsis.

Patients and Methods

This study was a two-center retrospective analysis. Medical data were collected from patients diagnosed with sepsis. The patients were divided into NOAF and non-NOAF groups, and the SIC score was calculated for each group. Univariable and multivariable logistic regression analyses were performed to explore the relationship between the SIC score and NOAF, as well as their effects on mortality. The Kaplan-Meier curve was used to assess the survival rate.

Results

A total of 2,280 septic patients were included, with 132 (5.7%) suffering from NOAF. Multivariable logistic regression analyses indicated that age, gender, the Acute Physiology and Chronic Health Evaluation II score (APACHE II), heart rate, renal failure, stroke, chronic obstructive pulmonary disease (COPD), and the SIC score were independent risk factors for NOAF in sepsis. Moreover, NOAF was associated with an increased risk of in-hospital mortality, 28-day mortality, and 90-day mortality. These results were consistent across subgroup analyses.

Conclusion

The SIC score was an independent risk factor for NOAF in septic patients, and NOAF was an independent risk factor for predicting mortality.

Impact of sodium-glucose cotransporter 2 inhibitor on recurrence and cardiovascular outcomes after catheter ablation for atrial fibrillation in patients with heart failure

BACKGROUND

The impact of sodium-glucose cotransporter 2 inhibitors (SGLT2i) on atrial fibrillation (AF) recurrence outcomes and adverse cardiovascular outcomes in heart failure (HF) patients after AF ablation is unknown.

OBJECTIVE

We investigated whether SGLT2i reduces the risk of AF recurrence and adverse cardiovascular outcomes in HF patients after AF ablation.

METHODS

HF patients with AF undergoing catheter ablation between January 2017 and December 2022 from the China-AF Registry were included. Patients were stratified into 2 groups on the basis of the use of SGLT2i at discharge and were 1:1 matched by propensity score, with SGLT2i using (n = 368) and non-SGLT2i using (n = 368) in each group. The primary outcome was AF recurrence after a 3-month blanking period.

RESULTS

During a total of 1315 person-years of follow-up, AF recurred in 83 patients (22.6%) in the SGLT2i group and 132 patients (35.8%) in the non-SGLT2i group. SGLT2i was associated with a lower risk of AF recurrence (adjusted hazard ratio, 0.56; 95% CI, 0.43-0.74; P < .001). The composite risk of cardiovascular death, thrombotic events, or cardiovascular hospitalization was significantly lower in the SGLT2i group compared with those without SGLT2i (adjusted hazard ratio, 0.58; 95% CI, 0.41-0.80; P = .001). Although there was a trend toward benefit, the differences in all-cause mortality, cardiovascular death, or thrombotic events were insignificant between the 2 groups.

CONCLUSION

The use of SGLT2i was associated with a lower risk of AF recurrence and the composite outcome of cardiovascular death, thrombotic events, or cardiovascular hospitalization after catheter ablation for AF in patients with HF.

Incidence and predictors of post-surgery atrial fibrillation occurrence: A cohort study in 53,387 patients

Introduction

Atrial fibrillation (AF) represents the most common arrhythmia in the postoperative setting. We aimed to investigate the incidence of postoperative AF (POAF) and determine its predictors, with a specific focus on inflammation markers.

Methods

We performed a retrospective single tertiary center cohort study including consecutive adult patients who underwent a major surgical procedure between January 2016 and January 2020. Patients were divided into four subgroups according to the type of surgery.

Results

Among 53,387 included patients (79.4% male, age 64.5 ± 9.5 years), POAF occurred in 570 (1.1%) with a mean latency after surgery of 3.4 ± 2.6 days. Ninety patients died (0.17%) after a mean of 13.7 ± 8.4 days. The 28-day arrhythmia-free survival was lower in patients undergoing lung and cardiovascular surgery (p < .001). Patients who developed POAF had higher levels of C-reactive protein (CRP) (0.70 ± 0.03 vs. 0.40 ± 0.01 log10 mg/dl; p < .001). In the multivariable Cox regression analysis, adjusting for confounding factors, CRP was an independent predictor of POAF [HR per 1 mg/dL increase in log-scale = 1.81 (95% CI 1.18-2.79); p = .007]. Moreover, independent predictors of POAF were also age (HR/1 year increase = 1.06 (95% CI 1.04-1.08); I < .001), lung and cardiovascular surgery (HR 23.62; (95% CI 5.65-98.73); p < .001), and abdominal and esophageal surgery (HR 6.26; 95% CI 1.48-26.49; p = .013).

Conclusions

Lung and cardiovascular surgery had the highest risk of POAF in the presented cohort. CRP was an independent predictor of POAF and postsurgery inflammation may represent a major driver in the pathophysiology of the arrhythmia.

Blockade of thromboxane A2 signaling attenuates ethanol-induced myocardial inflammatory response in mice

BACKGROUND

Alcohol-associated cardiomyopathy (ACM) is a cardiac muscle disease characterized by inflammation and oxidative stress. Thromboxane-prostanoid receptor (TP-R) plays an important role in the pathogenesis of cardiovascular disease. Herein, we hypothesize that TP-R mediates alcohol-induced early cardiac injury.

METHODS

Eight-week-old male C57BL/6 wild-type mice were fed a chronic ethanol (ET) or control diet (CON) for 10 days followed by a single binge of ethanol or maltose-dextrin through oral gavage. A cohort of ethanol-fed mice received SQ 29,548 (SQ), a TP-R antagonist. RNA sequencing, real-time PCR, and western blot analysis were performed on left ventricle to investigate alterations in genes and/or proteins mediating oxidative stress, inflammation, and cardiac remodeling. Sirius Red staining was performed to measure myocardial fibrosis.

RESULTS

RNA-sequencing analysis of myocardium from CON and ET groups identified 142 genes that were significantly altered between the two groups. In particular, the gene expression of thioredoxin-interacting protein (TXNIP), a component of NLR family pyrin domain containing 3 (NLRP3) signaling, which mediates oxidative stress and inflammatory response, was upregulated in response to ethanol exposure. The myocardial protein levels of TP-R and thromboxane A2 synthase were increased upon alcohol exposure. Ethanol increased the levels of 4-hydroxynonenal, a marker of oxidative stress, with a concomitant increase in the protein levels of TXNIP and NLRP3, and administration of SQ attenuated these effects. Additionally, ethanol increased the protein levels of pro-inflammatory mediators, including tumor necrosis factor alpha and the NLRP3 downstream product, secretory interleukin 1 beta, and SQ blunted these effects. Finally, the Sirius red staining of the myocardium revealed an increase in collagen deposition in ethanol-fed mice which was attenuated by TP-R antagonism.

CONCLUSION

This study demonstrates that ethanol promotes the NLRP3 signaling pathway within the myocardium, leading to a pro-inflammatory milieu that potentially initiates early myocardial remodeling, and TP-R antagonism attenuates this effect.

Conventional and Novel Inflammatory Biomarkers in Chronic Heart Failure Patients with Atrial Fibrillation

(1) Background and Objectives: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with increased morbidity and mortality both in the general population and heart failure patients. Inflammation may promote the initiation, maintenance and perpetuation of AF, but the impact of inflammatory molecular signaling on the association between AF and heart failure remains elusive. (2) Materials and Methods: In 111 patients with chronic stable heart failure, baseline values of conventional (IL-6 and hsCRP) and selected novel inflammatory biomarkers (IL-10, IL-6/IL-10 ratio, orosomucoid and endocan) were determined. Inflammatory biomarkers were compared with respect to the presenting cardiac rhythm. (3) Results: Patients aged below 75 years with AF had significantly higher values of IL-6 and IL-6/IL-10 ratio; IL-6 levels were a significant predictor of AF in both univariate (OR 1.175; 95%CI 1.013-1.363; p = 0.034) and multivariate logistic regression analysis when accounting for other inflammatory biomarkers (OR 1.327; 95% CI 1.068-1.650; p = 0.011). Conversely, there was no association between other novel inflammatory biomarkers and AF. (4) Conclusions: IL-6 levels and the IL-6/IL-10 ratio are associated with AF in patients with chronic stable heart failure under the age of 75 years, suggesting that inflammatory molecular signaling may play a role in the development of AF in the heart failure population.

NLRP3 Expression and Its Predictive Role in Heart Failure with Preserved Ejection Fraction among Non-Valvular Atrial Fibrillation Patients

INTRODUCTION

The aim of this study was to investigate the expression and predictive value of NOD-like receptor thermal protein domain-related protein 3 (NLRP3) in patients with non-valvular atrial fibrillation (NVAF) with heart failure with preserved ejection fraction (HFpEF).

METHODS

This was a retrospective analysis of 121 patients diagnosed with NVAF. According to the occurrence of HFpEF, 81 patients were assigned to the NVAF group and 40 patients to the NVAF/HFpEF group. The levels of NLRP3, B natriuretic peptide (BNP), and interleukin-1β (IL-1β) were determined using ELISA. Independent predictors for HFpEF in NVAF were determined using logistic regression. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of each factor.

RESULTS

Expression levels of NLRP3, BNP, and IL-1β in the NVAF/HFpEF group, as well as the H2FPEF score were significantly higher than those in the NVAF group. Pearson analysis showed that NLRP3, BNP, and IL-1β expression levels in NVAF patients and the H2FPEF score was positively correlated (r = 0.409, r = 0.244, r = 0.299, p < 0.001). Multivariate logistic regression analysis showed that the NLRP3, BNP, or H2FPEF score can be used as independent factor for predicting the occurrence of HFpEF in NVAF. ROC curves showed that the areas under the curve of NLRP3, BNP, and H2FPEF scores for predicting the occurrence of HFpEF in NVAF patients were 0.856, 0.831, and 0.811, respectively.

CONCLUSION

The NLRP3 level is elevated in the peripheral blood of NVAF patients with HFpEF and is positively correlated with the H2FPEF score. NLRP3 may serve as a potential predictor of HFpEF in patients with NVAF.

Factors predicting the recurrence of atrial fibrillation after catheter ablation: A review

Atrial fibrillation (AF) is the most common and clinically significant type of cardiac arrhythmia. Although catheter ablation (CA) can restore sinus rhythm in patients with AF, some patients experience recurrence after the procedure. This requires us to find a simple and effective way to identify patients at a high risk of recurrence and to intervene early in the high-risk population to improve patient prognosis. The mechanism of AF recurrence is unclear, but it involves several aspects including patient history, inflammation, myocardial fibrosis, and genes. This article summarizes the current predictors of AF recurrence after CA, including myocardial fibrosis markers, inflammatory markers, MicroRNAs, Circular RNAs, AF recurrence scores, and imaging indicators. Each predictor has its own scope of application, and the predictive capacity and joint application of multiple predictors may improve the predictive power. In addition, we summarize the mechanisms involved in AF recurrence. We hope that this review will assist researchers understand the current predictors of AF recurrence and help them conduct further related studies.

Identification of key differentially expressed immune related genes in patients with persistent atrial fibrillation: an integrated bioinformation analysis

OBJECTIVE

We aimed to investigate key differentially expressed immune related genes in persistent atrial fibrillation.

METHODS

Gene expression profiles were downloaded from Gene Expression Omnibus (GEO) using "GEO query" package. "limma" package and "sva" package were used to conduct normalization and eliminate batch effects, respectively. We screened out differentially expressed genes (DEGs) based on "limma" package with the standard of |log fold change (FC)| ≥ 1.5 and false discovery rate (FDR) < 0.05. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed by "clusterProfler" package. We further applied LASSO to select key DEGs, and intersected key DEGs with immune related genes from ImmPort database. The ROC curve of each DEIRG was constructed to evaluate its diagnostic efficiency for AF.

RESULTS

A total of 103 DEGs we were screened out, of them, 48 genes were down-regulated and 55 genes were up-regulated. Result of functional enrichment analysis show that, most of DEGs were related to immune response, inflammation, and oxidative stress. Ultimately, CYBB, RORB, S100A12, and CHGB were determined as key DEIRGs, each of which displayed a favor efficiency for diagnosing persistent AF.

CONCLUSION

CYBB, RORB, S100A12, and CHGB were identified as key DEIRGs in persistent AF, and future studies are needed to further explore the underlying roles of CYBB, RORB, S100A12, and CHGB in persistent AF.

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.

LNK/SH2B3 loss of function increases susceptibility to murine and human atrial fibrillation

AIMS

The lymphocyte adaptor protein (LNK) is a negative regulator of cytokine and growth factor signalling. The rs3184504 variant in SH2B3 reduces LNK function and is linked to cardiovascular, inflammatory, and haematologic disorders, including stroke. In mice, deletion of Lnk causes inflammation and oxidative stress. We hypothesized that Lnk-/- mice are susceptible to atrial fibrillation (AF) and that rs3184504 is associated with AF and AF-related stroke in humans. During inflammation, reactive lipid dicarbonyls are the major components of oxidative injury, and we further hypothesized that these mediators are critical drivers of the AF substrate in Lnk-/- mice.

METHODS AND RESULTS

Lnk-/- or wild-type (WT) mice were treated with vehicle or 2-hydroxybenzylamine (2-HOBA), a dicarbonyl scavenger, for 3 months. Compared with WT, Lnk-/- mice displayed increased AF duration that was prevented by 2-HOBA. In the Lnk-/- atria, action potentials were prolonged with reduced transient outward K+ current, increased late Na+ current, and reduced peak Na+ current, pro-arrhythmic effects that were inhibited by 2-HOBA. Mitochondrial dysfunction, especially for Complex I, was evident in Lnk-/- atria, while scavenging lipid dicarbonyls prevented this abnormality. Tumour necrosis factor-α (TNF-α) and interleukin-1 beta (IL-1β) were elevated in Lnk-/- plasma and atrial tissue, respectively, both of which caused electrical and bioenergetic remodelling in vitro. Inhibition of soluble TNF-α prevented electrical remodelling and AF susceptibility, while IL-1β inhibition improved mitochondrial respiration but had no effect on AF susceptibility. In a large database of genotyped patients, rs3184504 was associated with AF, as well as AF-related stroke.

CONCLUSION

These findings identify a novel role for LNK in the pathophysiology of AF in both experimental mice and humans. Moreover, reactive lipid dicarbonyls are critical to the inflammatory AF substrate in Lnk-/- mice and mediate the pro-arrhythmic effects of pro-inflammatory cytokines, primarily through electrical remodelling.

Human Gut Microbiota in Cardiovascular Disease

The gut ecosystem, termed microbiota, is composed of bacteria, archaea, viruses, protozoa, and fungi and is estimated to outnumber human cells. Microbiota can affect the host by multiple mechanisms, including the synthesis of metabolites and toxins, modulating inflammation and interaction with other organisms. Advances in understanding commensal organisms' effect on human conditions have also elucidated the importance of this community for cardiovascular disease (CVD). This effect is driven by both direct CV effects and conditions known to increase CV risk, such as obesity, diabetes mellitus (DM), hypertension, and renal and liver diseases. Cardioactive metabolites, such as trimethylamine N -oxide (TMAO), short-chain fatty acids (SCFA), lipopolysaccharides, bile acids, and uremic toxins, can affect atherosclerosis, platelet activation, and inflammation, resulting in increased CV incidence. Interestingly, this interaction is bidirectional with microbiota affected by multiple host conditions including diet, bile acid secretion, and multiple diseases affecting the gut barrier. This interdependence makes manipulating microbiota an attractive option to reduce CV risk. Indeed, evolving data suggest that the benefits observed from low red meat and Mediterranean diet consumption can be explained, at least partially, by the changes that these diets may have on the gut microbiota. In this article, we depict the current epidemiological and mechanistic understanding of the role of microbiota and CVD. Finally, we discuss the potential therapeutic approaches aimed at manipulating gut microbiota to improve CV outcomes. © 2024 American Physiological Society. Compr Physiol 14:5449-5490, 2024.

Genetically predicted inflammatory proteins and the risk of atrial fibrillation: a bidirectional Mendelian randomization study

Purpose

The causal associations between inflammatory factors and atrial fibrillation (AF) remained unclear. We aimed to investigate whether genetically predicted inflammatory proteins are related to the risk of AF, and vice versa.

Methods

A bidirectional two-sample Mendelian randomization study was performed. The genetic variation of 91 inflammatory proteins were derived from genome-wide association study (GWAS) data of European ancestry (n = 14,824). Summary statistics for AF were obtained from a published meta-analysis study (n = 1,030,836) and the FinnGen study (n = 261,395).

Results

Genetically predicted fibroblast growth factor 5 (FGF5) was significantly positively associated with risk of AF [[odds ratio (OR): 1.07; 95% CI: 1.04-1.10; P < 0.01], and CD40l receptor was significantly negatively associated with risk of AF (OR: 0.95; 95% CI: 0.92-0.98; P = 0.02) in the meta-analysis study. In the FinnGen study, similar results were observed in FGF5 (OR: 1.11; 95% CI: 1.06-1.16; P < 0.01) and CD40l receptor (OR: 0.93; 95% CI: 0.89-0.97; P = 0.03) for AF. In the FinnGen study, TNF-beta was significantly positively associated with risk of AF (OR: 1.05; 95% CI: 1.02-1.09; P = 0.03) and leukemia inhibitory factor receptor was significantly negatively associated with risk of AF (OR: 0.86; 95% CI: 0.80-0.91; P = 0.001). The causal effect of AF on inflammatory proteins was not observed.

Conclusion

Our study suggested that FGF5 and CD40l receptor have a potential causal association with AF, and targeting these factors may help in the treatment of AF.

Repurposing Metformin for the Treatment of Atrial Fibrillation: Current Insights

Metformin is an orally effective anti-hyperglycemic drug that despite being introduced over 60 years ago is still utilized by an estimated 120 to 150 million people worldwide for the treatment of type 2 diabetes (T2D). Metformin is used off-label for the treatment of polycystic ovary syndrome (PCOS) and for pre-diabetes and weight loss. Metformin is a safe, inexpensive drug with side effects mostly limited to gastrointestinal issues. Prospective clinical data from the United Kingdom Prospective Diabetes Study (UKPDS), completed in 1998, demonstrated that metformin not only has excellent therapeutic efficacy as an anti-diabetes drug but also that good glycemic control reduced the risk of micro- and macro-vascular complications, especially in obese patients and thereby reduced the risk of diabetes-associated cardiovascular disease (CVD). Based on a long history of clinical use and an excellent safety record metformin has been investigated to be repurposed for numerous other diseases including as an anti-aging agent, Alzheimer's disease and other dementias, cancer, COVID-19 and also atrial fibrillation (AF). AF is the most frequently diagnosed cardiac arrythmia and its prevalence is increasing globally as the population ages. The argument for repurposing metformin for AF is based on a combination of retrospective clinical data and in vivo and in vitro pre-clinical laboratory studies. In this review, we critically evaluate the evidence that metformin has cardioprotective actions and assess whether the clinical and pre-clinical evidence support the use of metformin to reduce the risk and treat AF.

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.

The prognostic potential of long noncoding RNA XIST in cardiovascular diseases: a review

There is a significant mortality rate associated with cardiovascular disease despite advances in treatment. long Non-coding RNAs (lncRNAs) play a critical role in many biological processes and their dysregulation is associated with a wide range of diseases in which their downstream pathways are disrupted. A lncRNA X-inactive specific transcript (XIST) is well known as a factor that regulates the physiological process of chromosome dosage compensation for females. According to recent studies, lncRNA XIST is involved in a variety of cellular processes, including apoptosis, proliferation, invasion, metastasis, oxidative stress and inflammation, through molecular networks with microRNAs and their downstream targets in neoplastic and non-neoplastic diseases. Because these cellular processes play a role in the pathogenesis of cardiovascular diseases, we aim to investigate the role that lncRNA XIST plays in this process. Additionally, we wish to determine whether it is a prognostic factor or a potential therapeutic target in these diseases.