Galectin-3 Regulates Atrial Fibrillation Remodeling and Predicts Catheter Ablation Outcomes

Atrial remodelling and atrial fibrillation self-sustaining: the role of circulating circDGCR8

AIMS

The prediction of atrial fibrillation (AF) progression and post-ablation recurrence is currently based on empirical estimates, leading to suboptimal predictive accuracy. This study investigates whether atrial remodelling, a key factor in the severity of atrial cardiomyopathy, could serve as a shared substrate influencing both AF progression and recurrence. We aimed to identify circular RNAs (circRNAs) associated with atrial remodelling and to evaluate their ability to predict AF progression and recurrence.

METHODS AND RESULTS

We assessed the differential expression of plasma circRNAs between paroxysmal (PAF) and persistent AF (PsAF) patients using microarray analysis. Selected candidate circRNAs were validated through qPCR following rigorous statistical and bioinformatics analysis. circDGCR8 was consistently found to be up-regulated in PsAF compared with PAF patients. Additionally, circDGCR8 was significantly up-regulated in human atrial fibroblasts treated with angiotensin II (AngII). Gain- and loss-of-function studies suggested that circDGCR8 could promote atrial remodelling at cellular level by enhancing collagen production and fibroblast proliferation. Overexpression of circDGCR8 in human cardiac fibroblasts significantly altered the gene expression spectrum, impacting pathways including IL-17 signalling and TNF signalling. Moreover, circDGCR8 levels were positively correlated with atrial fibrosis, as indicated by increased percentages of low voltage zones. The predictive value of circDGCR8 was evaluated in two cohorts: (i) PAF patients monitored for 36 months with progression to PsAF as the endpoint, and (ii) AF patients who underwent radiofrequency ablation followed for 12 months to assess recurrence. In both cohorts, higher level of circDGCR8 was associated with increased risks of AF progression and post-ablation recurrence.

CONCLUSION

Our results suggest that circDGCR8, associated with atrial remodelling, holds potential as a predictive biomarker for both AF progression and post-ablation recurrence.

Atrial Translocation of Porphyromonas gingivalis Exacerbates Atrial Fibrosis and Atrial Fibrillation

BACKGROUND

Recent studies have indicated an association between periodontitis and atrial fibrillation (AF), although the underlying mechanisms remain unclear. Porphyromonas gingivalis is a causative agent of periodontal disease and is highly pathogenic. This study focused on P gingivalis and aimed to investigate the relationship among periodontitis, atrial translocation of P gingivalis, and atrial fibrosis and AF.

METHODS

An experiment was conducted using P gingivalis-infected C57BL/6J mice, in which P gingivalis was inoculated into the pulp of the molars. Immunohistochemistry was used to visualize the localization of P gingivalis, and loop-mediated isothermal amplification was employed to detect P gingivalis DNA in the left atrium. AF inducibility was examined by intracardiac stimulation. Moreover, left atrial appendage specimens were obtained from 68 patients with AF. A periodontal examination was conducted before the surgery, and the periodontal epithelial surface area and periodontal inflamed surface area, which are quantitative indices used to determine the clinical severity of periodontitis, were measured. The bacterial number of P gingivalis in human atrial tissue was analyzed via quantitative polymerase chain reaction. Atrial fibrosis was assessed using Azan-Mallory staining.

RESULTS

The translocation path of P gingivalis from the dental granuloma to the left atrium via the circulatory system was demonstrated by immunohistochemistry and loop-mediated isothermal amplification in P gingivalis-infected mice, which showed a higher degree of atrial fibrosis (21.9% versus 16.3%; P=0.0003) and a higher AF inducibility (30.0% versus 5.0%; P=0.04) than the control mice. Upregulation of GAL3 (galectin 3) and transforming growth factor-beta 1 in the left atrium was observed in P gingivalis-infected mice. Moreover, immunohistochemistry revealed that P gingivalis was also present in human atrial tissue. The number of P gingivalis in the human atrial tissue was positively correlated with periodontal epithelial surface area (ρ=0.35; P=0.004), periodontal inflamed surface area (ρ=0.52, P<0.0001), and the degree of atrial fibrosis (ρ=0.38; P=0.002).

CONCLUSIONS

P gingivalis translocation to the left atrium correlates with the clinical severity of periodontitis, which may exacerbate atrial fibrosis and AF. Atrial translocation of P gingivalis is a potential pathway explaining the causal relationship between periodontitis and AF.

The Predictive Value of Circulating Gal-3 for New Stroke Events in Paroxysmal Atrial Fibrillation Patients Despite Oral Anticoagulation Medications

BACKGROUND

CHA2DS2-VASc is used to assess the risk of stroke in patients with atrial fibrillation (AF) and guide anticoagulant treatment decisions, but it has limitations in accurately predicting stroke risk in individual patients. The objective of this study is to conduct a cohort study by assessing preoperative levels of Gal-3 in paroxysmal AF patients, aiming to observe its correlation with the subsequent incidence of stroke events.

METHOD

This study enrolled 197 patients with nonvalvular paroxysmal AF. Blood samples were taken to test Gal-3 levels. All patients were followed up for 4 years after admission.

RESULTS

Compared to the nonstroke cases, serum levels of Gal-3 were markedly elevated in stroke cases (7.08 [IQR, 4.60-10.96] vs. 17.34 [IQR, 8.28-20.31], p < 0.001). Gal-3 yields a superior AUC (0.748, with a 95%CI of 0.681-0.807) compared to other classical stroke indices, such as BNP, CHA2DS2-Vas score, and TNI. Remarkably, the Gal-3 index exhibited a superior predictive capacity, yielding a significant incremental predictive value that surpassed the conventional risk factors (CHA2DS2-VASc score) for stroke events, as evidenced by an IDI of 16.4% (p < 0.001) and an NRI of 34.7% (p = 0.002).

CONCLUSION

The presence of Gal-3 is an independent risk factor for stroke in patients with AF. Elevated levels of Gal-3 have the potential to serve as a valuable biomarker for identifying incident strokes in AF patients. Furthermore, incorporating the assessment of Gal-3 levels into the conventional CHA2DS2-VASc score could significantly enhance its predictive accuracy for stroke in AF patients.

Metabolomics in Atrial Fibrillation: Unlocking Novel Biomarkers and Pathways for Diagnosis, Prognosis, and Personalized Treatment

BACKGROUND/OBJECTIVES

Atrial fibrillation (AF) is the most frequent arrhythmia in the adult population associated with a high rate of severe consequences leading to significant morbidity and mortality worldwide. Therefore, its prompt recognition is of high clinical importance. AF detection often remains challenging due to unspecific symptoms and a lack of reliable biomarkers for its prediction. Herein, novel bioanalytical methodologies, such as metabolomics, offer new opportunities for a better understanding of the underlying pathological mechanisms of cardiovascular diseases, including AF. The metabolome, considered a complete set of small molecules present in the organism, directly reflects the current phenotype of the studied system and is highly sensitive to any changes, including arrhythmia's onset. A growing body of evidence suggests that metabolite profiling has prognostic value in AF prediction, highlighting its potential role not only in early diagnosis but also in guiding therapeutic interventions. By identifying specific metabolites as a disease biomarker or recognising particular metabolomic pathways involved in the AF pathomechanisms, metabolomics could be of great clinical value for further clinical decision-making, risk stratification, and an individual personalised approach. The presented narrative review aims to summarise the current state of knowledge on metabolomics in AF with a special emphasis on its implications for clinical practice and personalised medicine.

Metabolomics in atrial fibrillation - A review and meta-analysis of blood, tissue and animal models

BACKGROUND

Atrial fibrillation (AF) is a highly prevalent cardiac arrhythmia associated with severe cardiovascular complications. AF presents a growing global challenge, however, current treatment strategies for AF do not address the underlying pathophysiology. To advance diagnosis and treatment of AF, a deeper understanding of AF root causes is needed. Metabolomics is a fast approach to identify, quantify and analyze metabolites in a given sample, such as human serum or atrial tissue. In the past two decades, metabolomics have enabled research on metabolite biomarkers to predict AF, metabolic features of AF, and testing metabolic mechanisms of AF in animal models. Due to the field's rapid evolution, the methods of AF metabolomics studies have not always been optimal. Metabolomics research has lacked standardization and requires expertise to face methodological challenges.

PURPOSE OF THE REVIEW

We summarize and meta-analyze metabolomics research on AF in human plasma and serum, atrial tissue, and animal models. We present the current progress on metabolic biomarkers candidates, metabolic features of clinical AF, and the translation of metabolomics findings from animal to human. We additionally discuss strengths and weaknesses of the metabolomics method and highlight opportunities for future AF metabolomics research.

Perioperative Pain Observation of Hip Fracture Surgery Patients with Cheek Acupuncture

Background

The objective of this study is to investigate the impact of cheek acupuncture on perioperative pain in patients with hip fracture.

Methods

A random number table was utilized to allocate the patients into three distinct cohorts: Only spinal anesthesia was performed (group S), cheek acupuncture was performed before spinal anesthesia (group C), and ultrasound-guided fascia iliaca block was performed before spinal anesthesia (group F). The primary outcome measure was the Visual Analogue Scale (VAS) score within 24 hours post-surgery, as well as the level of beta-endorphin. The secondary outcome measures included intraoperative mean arterial pressure (MAP), heart rate (HR), length of hospital stay, postoperative complications, levels of interleukin-6 (IL-6), and degree of motor block.

Results

Compared to Group S, patients in group C and group F exhibited significantly lower Visual Analog Scale (VAS) scores at the following endpoints: when the patient is positioned in the spinal anesthesia position (T2); 12 hours post-surgery (T5); and 24 hours post-surgery (T6). And patients in group C and group F demonstrated a decreased beta-endorphin level at the T6. Compared to Group S, patients in group C and group F displayed reduced Mean Arterial Pressure (MAP) levels at T2.

Conclusion

The application of cheek acupuncture therapy in hip fracture surgery can effectively reduce the Visual Analog Scale (VAS) score, enhance perioperative safety, facilitate postoperative recovery, and optimize the overall medical experience for patients.

Clinical Trial

ChiCTR2100043194.

Galectin-3 Predicts Long-Term Risk of Cerebral Disability and Mortality in Out-of-Hospital Cardiac Arrest Survivors

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is associated with high mortality and cerebral disability in survivors. Current models of risk prediction and survival are mainly based on resuscitation duration. We examined the prognostic value of circulating biomarkers in predicting mortality and severe cerebral disability for OHCA survivors, alongside traditional clinical risk indicators.

METHODS

Biomarkers including BNP, troponin I, and galectin-3 were measured at hospital admission in resuscitated OHCA patients. Prognostic significance for mortality and cerebral disability involving circulating biomarkers, resuscitation duration, demographics, and laboratory and clinical characteristics was examined via univariate and multivariate Cox proportional hazards regression models. The incremental prognostic value of the index covariates was examined through model diagnostics, focusing on the Akaike information criterion (AIC) and Harrell's concordance statistic (c-statistic).

RESULTS

In a combinatorial analysis of 144 OHCA survivors (median follow-up 5.7 years (IQR 2.9-6.6)), BNP, galectin-3, arterial pH, and resuscitation time were significant predictors of all-cause death and severe cerebral disability, whereas troponin I levels were not. Multivariate regression, adjusting for BNP, arterial pH, and resuscitation time, identified galectin-3 as an independent predictor of long-term mortality. Multiple linear regression models also confirmed galectin-3 as the strongest predictor of cerebral disability. The incorporation of galectin-3 into models for predicting mortality and cerebral disability enhanced fit and discrimination, demonstrating the incremental value of galectin-3 beyond traditional risk predictors.

CONCLUSIONS

Galectin-3 is a significant, independent long-term risk predictor of cerebral disability and mortality in OHCA survivors. Incorporating galectin-3 into current risk stratification models may enhance early prognostication and guide targeted clinical interventions.

Paradoxical SERCA dysregulation contributes to atrial fibrillation in a model of diet-induced obesity

Obesity is a major risk factor for atrial fibrillation (AF) the most common serious cardiac arrhythmia, but the molecular mechanisms underlying diet-induced AF remain unclear. In this study, we subjected mice to a chronic high-fat diet and acute sympathetic activation ('two-hit' model) to study the mechanisms by which diet-induced obesity promotes AF. Surface electrocardiography revealed that diet-induced obesity and sympathetic activation synergize during intracardiac tachypacing to induce AF. At the cellular level, diet-induced obesity and acute adrenergic stimulation facilitate the formation of delayed afterdepolarizations in atrial myocytes, implicating altered Ca2+ dynamics as the underlying cause of AF. We found that diet-induced obesity does not alter the expression of major Ca2+-handling proteins in atria, including the sarcoplasmic reticulum Ca2+-ATPase (SERCA), a major component of beat-to-beat Ca2+ cycling in the heart. Paradoxically, obesity reduces phospholamban phosphorylation, suggesting decreased SERCA activity, yet atrial myocytes from obese mice showed a significantly increased Ca2+ transient amplitude and SERCA-mediated Ca2+ uptake. Adrenergic stimulation further increases the Ca2+ transient amplitude but does not affect Ca2+ reuptake in atrial myocytes from obese mice. Transcriptomics analysis showed that a high-fat diet prompts upregulation of neuronatin, a protein that has been implicated in obesity and is known to stimulate SERCA activity. We propose a mechanism in which obesity primes SERCA for paradoxical activation, and adrenergic stimulation facilitates AF conversion through a Ca2+-induced Ca2+ release gain in atrial myocytes. Overall, this study links obesity, altered Ca2+ signaling, and AF, and targeting this mechanism may prove effective for treating obesity-induced AF.

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

Proteomics couples electrical remodelling to inflammation in a murine model of heart failure with sinus node dysfunction

AIMS

In patients with heart failure (HF), concomitant sinus node dysfunction (SND) is an important predictor of mortality, yet its molecular underpinnings are poorly understood. Using proteomics, this study aimed to dissect the protein and phosphorylation remodelling within the sinus node in an animal model of HF with concurrent SND.

METHODS AND RESULTS

We acquired deep sinus node proteomes and phosphoproteomes in mice with heart failure and SND and report extensive remodelling. Intersecting the measured (phospho)proteome changes with human genomics pharmacovigilance data, highlighted downregulated proteins involved in electrical activity such as the pacemaker ion channel, Hcn4. We confirmed the importance of ion channel downregulation for sinus node physiology using computer modelling. Guided by the proteomics data, we hypothesized that an inflammatory response may drive the electrophysiological remodeling underlying SND in heart failure. In support of this, experimentally induced inflammation downregulated Hcn4 and slowed pacemaking in the isolated sinus node. From the proteomics data we identified proinflammatory cytokine-like protein galectin-3 as a potential target to mitigate the effect. Indeed, in vivo suppression of galectin-3 in the animal model of heart failure prevented SND.

CONCLUSION

Collectively, we outline the protein and phosphorylation remodeling of SND in heart failure, we highlight a role for inflammation in electrophysiological remodelling of the sinus node, and we present galectin-3 signalling as a target to ameliorate SND in heart failure.

Toxicological evaluation of a pumpkin-derived pectin preparation: in vitro genotoxicity studies and a 13-week oral toxicity study in Sprague-Dawley rats

The safety of a rhamnogalacturonan-I-enriched pectin extract (G3P-01) from pumpkin (Cucurbita moschata var. Dickinson) was evaluated for use as an ingredient in food and dietary supplements. G3P-01 was tested in a battery of genetic toxicity studies including reverse mutagenicity and in vitro micronucleus assay. In addition, Sprague-Dawley rats were randomized and orally dosed with G3P-01 incorporated in animal diet at concentrations of 0, 9000, 18,000, and 36,000 ppm daily for 13-weeks (n=10/sex/group) in line with OECD guidelines (TG 408). The results of the in vitro bacterial reverse mutation assay and micronucleus assay in TK6 cells demonstrated a lack of genotoxicity. The 13-week oral toxicity study in Sprague-Dawley rats demonstrated that the test article, G3P-01 was well tolerated; there were no mortalities and no adverse effects on clinical, gross pathology, hematology, blood chemistry, and histological evaluation of the essential organs of the animals. The present study demonstrates that G3P-01 is non-genotoxic and is safe when ingested in diet at concentrations up to 36, 000 ppm. The subchronic no-observed-adverse-effect level (NOAEL) for G3P-01 was concluded to be 36,000 ppm, equivalent to 1,899 and 2,361 mg/kg/day for male and female rats respectively.

The role of galectin-3 in atrial fibrillation

Numerous risk factors for atrial fibrillation (AF) progression have been identified. However, the biomarkers mentioned in the guidelines do not have any clinically relevant predictive value. Some research groups investigated the potential utility of galectin-3 (gal-3) as a diagnostic, prognostic, and predictive biomarker in AF. In this review, we have thoroughly summarized the current data on the role of gal-3 in AF based on the original research in this field. Patients suffering from AF present with increased levels of gal-3. The concentration of gal-3 differs between patients with AF depending on the type of AF - it is higher in patients with persistent AF than in patients with paroxysmal AF. Multiple studies investigating the reappearance of AF in patients who underwent ablation have shown that gal-3 is a promising biomarker to predict the outcome of this therapy. Patients with increased levels of gal-3 are at higher risk of AF recurrence. Although the research considered in this work addressed many aspects of the role of gal-3 in AF, most of it has been conducted on a small group of patients. Therefore, further research and extensive clinical trials confirming described findings are highly warranted.

The role of galectin-3 in patients with permanent and paroxysmal Atrial Fibrillation and echocardiographic parameters of left atrial fibrosis

BACKGROUND

Biochemical markers and imaging tests have been used with the aim of stratifying the risk and detecting atrial fibrosis. Speckle-tracking echocardiography (STE) is used for the detection of atrial fibrosis and Gal-3 provides an important prognostic value. The objective of the study was to assess the association between atrial fibrosis markers and serum levels, genetic polymorphisms and genic expression of galectin-3.

METHODS

206 patients with permanent AF and 70 patients with paroxysmal AF were included in the study. Real time PCR (TaqMan) system was used to study SNPs rs4652 and 4644 of the gene LGALS3. Serum levels of Gal-3 were determined by ELISA and STE was performed to assess fibrosis.

RESULTS

Mean age of individuals with permanent AF was 66.56 ± 12 years. As for the echocardiography results, those patients showed an decrease in the following parameters peak atrial longitudinal strain (PALS) (p = 0.002) when compared to the same parameters from the paroxysmal AF group of patients. There was a correlation between serum levels of Gal-3 and PALS in the group of patients with permanent AF; the lower the levels of gal-3, the lower the LA strain (r = 0.24; p = 0.01).

CONCLUSIONS

Echocardiographic findings showed association with the groups, and with serum levels of Gal-3 in patients with permanent AF. The distribution of allelic and genotypic frequencies, and of the haplotypes of polymorphism LGALS3 rs4652 and rs4644 did not present statistical variation, which suggests that those SNPs are not associated with the AF clinical forms (permanent and paroxysmal).

Galectin-3 as a Prognostic Biomarker in Patients with First Acute Myocardial Infarction without Heart Failure

BACKGROUND

Galectin-3 (Gal-3) is a biomarker involved in a wide range of diseases including cardiac remodeling following acute myocardial infarction (AMI). Identification of prognostic markers in patients with AMI can guide strategies towards improved survival and quality of life.

METHODS

Our study included 59 patients with AMI and a preserved ejection fraction. We determined the Gal-3 plasma concentration within 24 h of chest pain onset from the aortic root, femoral/radial artery, coronary sinus and cubital vein. Major adverse cardiovascular events (MACEs) were evaluated at six months follow-up.

RESULTS

MACE at six months post-AMI was recorded in 20 patients (34%). The Gal-3 plasma concentration from the aortic root and the femoral/radial artery were independent predictors of MACE at six months follow-up after the first AMI (OR 1.228; 95%CI: 1.011-1.491; p = 0.038; OR 3.438; 95%CI: 1.275-9.265; p = 0.015). ROC analysis identifies the Gal-3 plasma concentration from the aortic root as a better predictor of MACE or death (cut-off ≥ 10.86 ng/mL; AUC 0.858; 95%CI: 0.744-0.973; p < 0.001) than Gal-3 plasma concentration from the femoral/radial artery (cut-off ≥ 10.18 ng/mL; AUC 0.742; 95%CI: 0.596-0.888; p = 0.006).

CONCLUSION

the Gal-3 plasma concentration in patients with AMI determined during coronary angiography, especially from the aortic root, within 24 h after chest pain onset is a valuable biomarker of prognosis at six months follow-up.

Insights into the Role of Galectin-3 as a Diagnostic and Prognostic Biomarker of Atrial Fibrillation

Atrial fibrillation (AF) is an irregular atrial activity and the most prevalent type of arrhythmia. Although AF is easily diagnosed with an electrocardiogram, there is a keen interest in identifying an easy-to-dose biomarker that can predict the prognosis of AF and its recurrence. Galectin-3 (Gal-3) is a beta-galactoside binding protein from the lectin family with pro-fibrotic and -inflammatory effects and a pivotal role in a variety of biological processes, cell proliferation, and differentiation; therefore, it is implicated in the pathogenesis of many cardiovascular (e.g., heart failure (HF)) and noncardiovascular diseases. However, its specificity and sensitivity as a potential marker in AF patients remain debated and controversial. This article comprehensively reviewed the evidence regarding the interplay between Gal-3 and patients with AF. Clinical implications of measuring Gal-3 in AF patients for diagnosis and prognosis are mentioned. Moreover, the role of Gal-3 as a potential biomarker for the management of AF recurrence is investigated. The association of Gal-3 and AF in special populations (coronary artery disease, HF, metabolic syndrome, chronic kidney disease, and diabetes mellitus) has been explored in this review. Overall, although further studies are needed to enlighten the role of Gal-3 in the diagnosis and treatment of AF, our study demonstrated the high potential of this molecule to be used and focused on by researchers and clinicians.

Atrial fibrillation ablation in patients with arrhythmia-induced cardiomyopathy: a prospective multicentre study

AIMS

This study aims to investigate the clinical and biochemical characteristics of patients with atrial fibrillation (AF) referred for ablation who develop arrhythmia-induced cardiomyopathy (AiCM) as well as their long-term outcomes after catheter ablation (CA).

METHODS AND RESULTS

A prospective multicentre study was conducted on consecutive AF patients who underwent CA. AiCM was defined as the development of heart failure in the presence of AF and an improvement of left ventricular fraction by at least 10% at 6 months after ablation. A subgroup of patients underwent peripheral and left atrial blood samples [galectin-3, fatty acid-binding protein 4 (FABP4), and soluble receptor for advanced glycation end products (sRAGE)] at the time of the procedure. Of the 769 patients who underwent AF ablation, 135 (17.56%) met the criteria for AiCM. Independent predictors of AiCM included persistent AF, male gender, left atrial volume, QRS width, active smoking, and chronic kidney disease (CKD). Biomarker analysis revealed that sRAGE, FABP4, and galectin-3 levels were not predictive of AiCM development nor did they differ between groups or predict recurrence. There were no differences in AF recurrence between patients with and without AiCM (30.83% vs. 27.77%; P = 0.392) during a median follow-up of 23.83 months (inter-quartile range 9-36).

CONCLUSIONS

In the subset of patients referred for AF ablation, the development of AiCM was associated with persistent AF and CKD. Biomarker analysis was not different between groups nor predicted recurrence. Patients with AiCM benefited from ablation, with a significant improvement in left ventricular ejection fraction and similar AF recurrence rates to those without AiCM.

Role of galectin-3 in the elastic response of radial growth phase melanoma cancer cells

Melanoma is originated from the malignant transformation of the melanocytes and is characterized by a high rate of invasion, the more serious stage compromising deeper layers of the skin and eventually leading to the metastasis. A high mortality due to melanoma lesion persists because most of melanoma lesions are detected in advanced stages, which decreases the chances of survival. The identification of the principal mechanics implicated in the development and progression of melanoma is essential to devise new early diagnosis strategies. Cell mechanics is related with a lot of cellular functions and processes, for instance motility, differentiation, migration and invasion. In particular, the elastic modulus (Young's modulus) is a very explored parameter to describe the cell mechanical properties; most cancer cells reported in the literature smaller elasticity modulus. In this work, we show that the elastic modulus of melanoma cells lacking galectin-3 is significantly lower than those of melanoma cells expressing galectin-3. More interestingly, the gradient of elastic modulus in cells from the nuclear region towards the cell periphery is more pronounced in shGal3 cells. RESEARCH HIGHLIGHTS: AFM imaging and force spectroscopy were used to investigate the morphology and elasticity properties of healthy HaCaT cells and melanoma cells WM1366, with (shSCR) and without (shGal3) expression of galectin-3. It is shown the effect of galectin-3 protein on the elastic properties of cells: the cells without expression of galectin-3 presents lower elastic modulus. By the results, we suggest here that galectin-3 could be used as an effective biomarker of malignancy in both melanoma diagnostic and prognosis.

Effects of Inflammatory Cell Death Caused by Catheter Ablation on Atrial Fibrillation

Atrial fibrillation (AF) poses a serious healthcare burden on society due to its high morbidity and the resulting serious complications such as thrombosis and heart failure. The principle of catheter ablation is to achieve electrical isolation by linear destruction of cardiac tissue, which makes AF a curable disease. Currently, catheter ablation does not have a high long-term success rate. The current academic consensus is that inflammation and fibrosis are central mechanisms in the progression of AF. However, artificially caused inflammatory cell death by catheter ablation may have a significant impact on structural and electrical remodeling, which may affect the long-term prognosis. This review first focused on the inflammatory response induced by apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis and their interaction with arrhythmia. Then, we compared the differences in cell death induced by radiofrequency ablation, cryoballoon ablation and pulsed-field ablation. Finally, we discussed the structural and electrical remodeling caused by inflammation and the association between inflammation and the recurrence of AF after catheter ablation. Collectively, pulsed-field ablation will be a revolutionary innovation with faster, safer, better tissue selectivity and less inflammatory response induced by apoptosis-dominated cell death.

The Role of Galectin-3 in Predicting Congenital Heart Disease Outcome: A Review of the Literature

Galectin-3 (Gal-3) is a novel pro-fibrotic biomarker that can predict both right and left cardiac dysfunction caused by various cardiovascular conditions. Its expression seems to be progressively altered with evolving cardiac remodeling processes, even before the onset of heart failure. Hence, Gal-3 has been found to be an individual predictor of acute and chronic heart failure or to serve as part of an integrated biomarker panel that can foresee adverse cardiac outcomes. In congenital heart disease (CHD), Gal-3 correlates with cardiac mortality and complications in both children and adults and is proposed as a therapeutic target in order to reverse the activation of pro-fibrosis pathways that lead to heart failure. Positive associations between serum Gal-3 levels, post-operatory hospitalization rates, complications and ventricular dysfunction have also been reported within studies conducted on patients with CHD who underwent corrective surgery. Thus, this review tried to address the potential utility of Gal-3 in patients with CHD and particularly in those who undergo corrective surgery. The heterogeneity of the literature data and the lack of validation of the results obtained by the current studies on larger cohorts cannot be neglected, though. Further longitudinal research is required to establish how Gal-3 can relate to long-term outcomes in pediatric CHD.

Long-Term Changes in the Biomarkers of Left Atrial Fibrosis after Pulmonary Vein Isolation for Paroxysmal and Persistent Atrial Fibrillation

Background

Atrial fibrillation (AF) is accompanied by inflammation and fibrosis to variable extent. The biomarkers of fibrosis were measured in patients with different forms of AF and cardiac status. Herein, we assessed the associations of the baseline concentrations of different biomarkers with the long-term success of pulmonary vein isolation (PVI) in patients with a structurally normal heart. Furthermore, we compared biomarker levels before and 3 years after ablation to gain further insights into the AF mechanism.

Methods

Patients, undergoing PVI for paroxysmal/persistent AF were enrolled prospectively. Blood samples were obtained 24 hours before and 3 years after ablation. Serum cancer antigen 125 (CA-125), plasma Caspase-3, Galectin-3 and Cathepsin L concentrations were measured. Follow-up visits every 6 months included 12-lead electrocardiogram, 24-hour Holter, trans-telephonic monitoring as well as transthoracic echocardiography after ablation. Biomarker levels, left ventricular ejection fraction and left atrial (LA) diameters at baseline and at the 3-year follow-up were compared in patients with versus without AF recurrence.

Results

A total of 63 patients were enrolled (23 women; age 61.4 ( ± 8.8) years). The acute isolation of all pulmonary veins was achieved in all patients. During a mean follow-up of 36.3 ± 6.3 months, AF recurrence was demonstrated in 26 (41.3%) patients. No significant differences were demonstrated in the levels of CA-125, Galectin-3, Caspase-3 and Cathepsin L pre- and post-ablation in patients with versus without AF recurrence. A significant decrease was detected in the concentrations of Caspase-3, Galectin-3 and Cathepsin L during follow-up with no difference in patients with versus without AF recurrence. A positive correlation was found between Caspase-3 levels and LA diameters in the AF recurrence group both before (r = 0.477; p = 0.018) and after the procedure (r = 0.533; p = 0.019).

Conclusions

Our results demonstrated that the levels of CA-125, Caspase-3, Cathepsin L and Galectin-3 are not associated with AF recurrence after PVI in patients with a structurally normal heart and mainly paroxysmal AF. Except for CA-125, all the other biomarkers demonstrated a significant decrease during a 3-year follow-up post-ablation. Furthermore, Caspase-3 levels demonstrated a positive correlation with LA dimensions in patients with AF recurrence.

Biomarkers of Atrial Fibrillation Recurrence in Patients with Paroxysmal or Persistent Atrial Fibrillation Following External Direct Current Electrical Cardioversion

Atrial fibrillation (AF) is associated with atrial remodeling, cardiac dysfunction, and poor clinical outcomes. External direct current electrical cardioversion is a well-developed urgent treatment strategy for patients presenting with recent-onset AF. However, there is a lack of accurate predictive serum biomarkers to identify the risks of AF relapse after electrical cardioversion. We reviewed the currently available data and interpreted the findings of several studies revealing biomarkers for crucial elements in the pathogenesis of AF and affecting cardiac remodeling, fibrosis, inflammation, endothelial dysfunction, oxidative stress, adipose tissue dysfunction, myopathy, and mitochondrial dysfunction. Although there is ample strong evidence that elevated levels of numerous biomarkers (such as natriuretic peptides, C-reactive protein, galectin-3, soluble suppressor tumorigenicity-2, fibroblast growth factor-23, turn-over collagen biomarkers, growth differential factor-15) are associated with AF occurrence, the data obtained in clinical studies seem to be controversial in terms of their predictive ability for post-cardioversion outcomes. Novel circulating biomarkers are needed to elucidate the modality of this approach compared with conventional predictive tools. Conclusions: Biomarker-based strategies for predicting events after AF treatment require extensive investigation in the future, especially in the presence of different gender and variable comorbidity profiles. Perhaps, a multiple biomarker approach exerts more utilization for patients with different forms of AF than single biomarker use.

Atrioventricular node dysfunction in pressure overload-induced heart failure—Involvement of the immune system and transcriptomic remodelling

Heart failure is associated with atrioventricular (AV) node dysfunction, and AV node dysfunction in the setting of heart failure is associated with an increased risk of mortality and heart failure hospitalisation. This study aims to understand the causes of AV node dysfunction in heart failure by studying changes in the whole nodal transcriptome. The mouse transverse aortic constriction model of pressure overload-induced heart failure was studied; functional changes were assessed using electrocardiography and echocardiography and the transcriptome of the AV node was quantified using RNAseq. Heart failure was associated with a significant increase in the PR interval, indicating a slowing of AV node conduction and AV node dysfunction, and significant changes in 3,077 transcripts (5.6% of the transcriptome). Many systems were affected: transcripts supporting AV node conduction were downregulated and there were changes in transcripts identified by GWAS as determinants of the PR interval. In addition, there was evidence of remodelling of the sarcomere, a shift from fatty acid to glucose metabolism, remodelling of the extracellular matrix, and remodelling of the transcription and translation machinery. There was evidence of the causes of this widespread remodelling of the AV node: evidence of dysregulation of multiple intracellular signalling pathways, dysregulation of 109 protein kinases and 148 transcription factors, and an immune response with a proliferation of neutrophils, monocytes, macrophages and B lymphocytes and a dysregulation of 40 cytokines. In conclusion, inflammation and a widespread transcriptional remodelling of the AV node underlies AV node dysfunction in heart failure.

Galectin-3 is an independent predictor of postoperative atrial fibrillation and survival after elective cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is a frequent complication after heart surgery and is associated with thromboembolic events, prolonged hospital stay, and adverse outcomes. Inflammation and fibrosis are involved in the pathogenesis of atrial fibrillation.

OBJECTIVE

The purpose of this study was to assess whether galectin-3, which reflects preexisting atrial fibrosis, has the potential to predict POAF and mortality after cardiac surgery.

METHODS

Four hundred seventy-five consecutive patients (mean age 67.4 ± 11.8 years; 336 (70.7%) male) undergoing elective heart surgery at the Medical University of Vienna were included in this prospective single-center cohort study. Galectin-3 plasma levels were assessed on the day before surgery.

RESULTS

The 200 patients (42.1%) who developed POAF had significantly higher galectin-3 levels (9.60 ± 6.83 ng/mL vs 7.10 ± 3.54 ng/mL; P < .001). Galectin-3 significantly predicted POAF in multivariable logistic regression analysis (adjusted odds ratio per 1-SD increase 1.44; 95% confidence interval 1.15-1.81; P = .002). During a median follow-up of 4.3 years (interquartile range 3.4-5.4 years), 72 patients (15.2%) died. Galectin-3 predicted all-cause mortality in multivariable Cox regression analysis (adjusted hazard ratio per 1-SD increase 1.56; 95% confidence interval 1.16-2.09; P = .003). Patients with the highest-risk galectin-3 levels according to classification and regression tree analysis (>11.70 ng/mL) had a 3.3-fold higher risk of developing POAF and a 4.4-fold higher risk of dying than did patients with the lowest-risk levels (≤5.82 ng/mL).

CONCLUSION

The profibrotic biomarker galectin-3 is an independent predictor of POAF and mortality after cardiac surgery. This finding highlights the role of the underlying arrhythmogenic substrate in the genesis of POAF. Galectin-3 may help to identify patients at risk of POAF and adverse outcome after cardiac surgery.

Circulating plasma galectin-3 predicts new-onset atrial fibrillation in patients after acute myocardial infarction during hospitalization

Background

New-onset atrial fibrillation (NOAF) is a common complication in patients with acute myocardial infarction (AMI) during hospitalization. Galectin-3 (Gal-3) is a novel inflammation marker that is significantly associated with AF. The association between post-AMI NOAF and Gal-3 during hospitalization is yet unclear.

Objective

The present study aimed to investigate the predictive value of plasma Gal-3 for post-AMI NOAF.

Methods

A total of 217 consecutive patients admitted with AMI were included in this retrospective study. Peripheral venous blood samples were obtained within 24 h after admission and plasma Gal-3 concentrations were measured.

Results

Post-AMI NOAF occurred in 18 patients in this study. Patients with NOAF were older (p < 0.001) than those without. A higher level of the peak brain natriuretic peptide (BNP) (p < 0.001) and Gal-3 (p < 0.001) and a lower low-density lipoprotein cholesterol level (LDL-C) (p = 0.030), and an estimated glomerular filtration rate (e-GFR) (p = 0.030) were recorded in patients with post-AMI NOAF. Echocardiographic information revealed that patients with NOAF had a significantly decreased left ventricular eject fraction (LVEF) (p < 0.001) and an increased left atrial diameter (LAD) (p = 0.004) than those without NOAF. The receiver operating characteristic (ROC) curve analysis revealed a significantly higher value of plasma Gal-3 in the diagnosis of NOAF for patients with AMI during hospitalization (area under the curve (p < 0.001), with a sensitivity of 72.22% and a specificity of 72.22%, respectively. Multivariate logistic regression model analysis indicated that age (p = 0.045), plasma Gal-3 (p = 0.018), and LAD (p = 0.014) were independent predictors of post-MI NOAF.

Conclusions

Plasma Gal-3 concentration is an independent predictor of post-MI NOAF.

Higher serum sST2 is associated with increased left atrial low-voltage areas and atrial fibrillation recurrence in patients undergoing radiofrequency ablation

OBJECTIVE

To conduct a comprehensive analysis of prospectively measuring the concentration of soluble suppression of tumorigenicity 2 (sST2) to predict left atrial (LA) low-voltage areas (LVAs) and atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFA).

METHODS

This was a prospective cohort study. A total of 84 patients, including 54 paroxysmal AF cases and 30 persistent AF cases who underwent RFA, were recruited. Electroanatomical voltage mapping determined the extent of LVAs. The serum level of sST2 was measured by enzyme-linked immunosorbent assay. All patients were followed for 12 months after the RFA procedure to verify AF recurrence.

RESULTS

The concentration of sST2 measured in the sample was 17.90-198.77 pg/mL, and the range of LA LVAs was 0-85.6%. The sST2 level positively correlated with LVAs (r = 0.40; P = 0.005). When comparing the top and bottom quartile, sST2 is significantly associated with LA LVAs (OR = 1.833, 95% CI: 1.582-2.011, P = 0.004). When compared with the 1st quartile group, the multivariable adjusted hazard ratios for AF recurrence after RFA were 1.57 (95% CI: 1.182-1.795) for the 4th quartile group, 1.44 (95% CI: 1.085-1.598) for the 3rd quartile group, and 1.27 (95% CI: 0.954-1.318) for the 2nd quartile group. The AF-free survival rates of patients with 1st quartile and 4th quartile sST2 levels after ablation were 95% and 59.6%, respectively (Log Rank test, P = 0.027).

CONCLUSION

Elevated sST2 levels of AF patients were associated with higher LA LVAs and a significantly increased risk of recurrence. The circulating sST2 concentration might be a pre-diagnostic marker of AF recurrence after RFA.

Aging Alters the Aortic Proteome in Health and Thoracic Aortic Aneurysm

BACKGROUND

Aging enhances most chronic diseases but its impact on human aortic tissue in health and in thoracic aortic aneurysms (TAA) remains unclear.

METHODS

We employed a human aortic biorepository of healthy specimens (n=17) and those that underwent surgical repair for TAA (n=20). First, we performed proteomics comparing aortas of healthy donors to aneurysmal specimens, in young (ie, <60 years of age) and old (ie, ≥60 years of age) subjects. Second, we measured proteins, via immunoblotting, involved in mitophagy (ie, Parkin) and also mitochondrial-induced inflammatory pathways, specifically TLR (toll-like receptor) 9, STING (stimulator of interferon genes), and IFN (interferon)-β.

RESULTS

Proteomics revealed that aging transformed the aorta both quantitatively and qualitatively from health to TAA. Whereas young aortas exhibited an enrichment of immunologic processes, older aortas exhibited an enrichment of metabolic processes. Immunoblotting revealed that the expression of Parkin directly correlated to subject age in health but inversely to subject age in TAA. In TAA, but not in health, phosphorylation of STING and the expression of IFN-β was impacted by aging regardless of whether subjects had bicuspid or tricuspid valves. In subjects with bicuspid valves and TAAs, TLR9 expression positively correlated with subject age. Interestingly, whereas phosphorylation of STING was inversely correlated with subject age, IFN-β positively correlated with subject age.

CONCLUSIONS

Aging transforms the human aortic proteome from health to TAA, leading to a differential regulation of biological processes. Our results suggest that the development of therapies to mitigate vascular diseases including TAA may need to be modified depending on subject age.

Immune remodeling and atrial fibrillation

Atrial fibrillation (AF) is a highly prevalent arrhythmia that causes high morbidity and mortality. However, the underlying mechanism of AF has not been fully elucidated. Recent research has suggested that, during AF, the immune system changes considerably and interacts with the environment and cells involved in the initiation and maintenance of AF. This may provide a new direction for research and therapeutic strategies for AF. In this review, we elaborate the concept of immune remodeling based on available data in AF. Then, we highlight the complex relationships between immune remodeling and atrial electrical, structural and neural remodeling while also pointing out some research gaps in these field. Finally, we discuss several potential immunomodulatory treatments for AF. Although the heterogeneity of existing evidence makes it ambiguous to extrapolate immunomodulatory treatments for AF into the clinical practice, immune remodeling is still an evolving concept in AF pathophysiology and further studies within this field are likely to provide effective therapies for AF.

The predictive value of galectin-3 levels on left atrial low voltage areas assessed by high-density mapping in patients with paroxysmal atrial fibrillation

Aims

Galectin-3 is an inflammation biomarker that is associated with atrial fibrosis and plays a role in the development of atrial fibrillation (AF). Low voltage areas (LVAs) identified using an electroanatomical mapping system represent the presence of fibrotic tissue. The present study aimed to determine the relationship between coronary sinus (CS) serum sampling of galectin-3 levels and the presence and extent of LVA in patients with paroxysmal AF.

Methods

A total of 115 consecutive paroxysmal AF patients underwent pulmonary vein isolation (PVI) included prospectively in the study. Voltage mapping was performed before PVI during sinus rhythm guided by multipolar high-density mapping catheter and LVAs were defined as regions where bipolar peak to peak voltage was <0.5 mV. Galectin-3 levels were measured via enzyme-linked immunosorbent assay.

Results

CS serum sampling of galectin-3 levels was significantly higher in paroxysmal AF patients with LVA than those without LVA (16.5 ± 3.7 ng/ml vs. 10.2 ±2.7 ng/ml, respectively, p < .001). CS serum sampling of galectin-3 levels was significantly higher in paroxysmal AF patients with moderate and severe LVA than in paroxysmal AF patients with mild LVA (17 ± 3.5 ng/ml and 20.1 ± 1.3 ng/ml vs. 13.3 ± 2.3 ng/ml, respectively, p = .002). In the multivariate analysis female gender (odds ratio [OR] = 7.537, 95% confidence interval [CI]: 1.011-56.195; p = .049), left atrium volume (OR = 1.326, 95% CI: 1.052-1.67; p = .017), and CS serum sampling of galectin-3 levels (OR = 1.704, 95% CI: 1.169-2.483; p = .006) were significant and independent predictors for LVAs.

Conclusion

In this study, we found that the CS serum sampling of galectin-3 levels increased with the extent of LVA and was an independent predictor for the presence of LVA.

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

Background

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

Methods

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

Results

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

Conclusion

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

A Scoping Review of Galectin-3 as a Biomarker of Cardiovascular Diseases in Pediatric Populations

Galectin-3 as a cardiac biomarker has proven to be a significant prognostic tool in adults. However, it has not yet been established in the pediatric population as a biomarker in daily clinical practice. The aim of the study was to summarize the current knowledge on galectin-3 as a biomarker in children with cardiac conditions by reviewing the literature. Bibliographic databases such as PubMed, Web of Science and Embase were searched, and consequently twelve articles met the inclusion criteria. Supplemental handsearching of references delivered one additional source. These prospective studies concerning galectin-3 as a cardiac biomarker present analyses performed in cohorts composed of healthy children and children with cardiovascular diseases. The results, despite being based on small cohort studies, inform that galectin-3 could serve as a potential biomarker in cardiovascular risk stratification in children with heart failure, arrhythmia, Kawasaki disease or in patients undergoing cardiac surgery. The evidence for the usefulness of galectin-3 in the assessment of such pathologies as idiopathic dilated cardiomyopathy, coarctation of the aorta, functionally univentricular heart or tetralogy of Fallot were not completely confirmed. Galectin-3 seems to be a promising biomarker; however, there is a need for further research to establish its use in daily clinical practice.

Galectin-3 enhances atrial remodelling and arrhythmogenesis through CD98 signalling

AIM

Galectin-3 (Gal-3) is a biomarker of atrial fibrillation (AF) that mediates atrial inflammation. CD98 is the membrane surface receptor for Gal-3. Nevertheless, the role of the Gal-3/CD98 axis in atrial arrhythmogenesis is unclear. In this study, we investigated the effects of Gal-3/CD98 signalling on atrial pathogenesis.

METHODS

Whole cell patch clamp and western blotting were used to analyse calcium/potassium homeostasis and calcium-related signalling in Gal-3-administrated HL-1 atrial cardiomyocytes with/without CD98 neutralized antibodies. Telemetry electrocardiographic recording, Masson's trichrome staining and immunohistochemistry staining of atrium were obtained from mice having received tail-vein injections with Gal-3.

RESULTS

Gal-3-treated HL-1 myocytes had a shorter action potential duration, smaller L-type calcium current, increased sarcoplasmic reticulum (SR) calcium content, Na⁺ /Ca²⁺ exchanger (NCX) current, transient outward potassium current, and ultrarapid delayed rectifier potassium current than control cells had. Gal-3-treated HL-1 myocytes had greater levels of SR Ca²⁺ ATPase, NCX, Nav1.5, and NLR family pyrin domain containing 3 (NLRP3) expression and increased calcium/calmodulin-dependent protein kinase II (CaMKII), ryanodine receptor 2 (RyR2), and nuclear factor kappa B (NF-κB) phosphorylation than control cells had. Gal-3-mediated activation of CaMKII/RyR2 pathway was diminished in the cotreatment of anti-CD98 antibodies. Mice that were injected with Gal-3 had more atrial ectopic beats, increased atrial fibrosis, and activated NF-κB/NLRP3 signalling than did control mice (nonspecific immunoglobulin) or mice treated with Gal-3 and anti-CD98 antibodies.

CONCLUSION

Gal-3 recombinant protein administration increases atrial fibrosis and arrhythmogenesis through CD98 signalling. Targeting Gal-3/CD98 axis might be a novel therapeutic strategy for patients with AF and high Gal-3 levels.

Nutrient-responsive O-GlcNAcylation dynamically modulates the secretion of glycan-binding protein galectin 3

Endomembrane glycosylation and cytoplasmic O-GlcNAcylation each play essential roles in nutrient sensing, and characteristic changes in glycan patterns have been described in disease states such as diabetes and cancer. These changes in glycosylation have important functional roles and can drive disease progression. However, little is known about the molecular mechanisms underlying how these signals are integrated and transduced into biological effects. Galectins are proteins that bind glycans and that are secreted by a poorly characterized nonclassical secretory mechanism. Once outside the cell, galectins bind to the terminal galactose residues of cell surface glycans and modulate numerous extracellular functions, such as clathrin-independent endocytosis (CIE). Originating in the cytoplasm, galectins are predicted substrates for O-GlcNAc addition and removal; and as we have shown, galectin 3 is a substrate for O-GlcNAc transferase. In this study, we also show that galectin 3 secretion is sensitive to changes in O-GlcNAc levels. We determined using immunoprecipitation and Western blotting that there is a significant difference in O-GlcNAcylation status between cytoplasmic and secreted galectin 3. We observed dramatic alterations in galectin 3 secretion in response to nutrient conditions, which were dependent on dynamic O-GlcNAcylation. Importantly, we showed that these O-GlcNAc-driven alterations in galectin 3 secretion also facilitated changes in CIE. These results indicate that dynamic O-GlcNAcylation of galectin 3 plays a role in modulating its secretion and can tune its function in transducing nutrient-sensing information coded in cell surface glycosylation into biological effects.

Therapeutic implications of galectin-3 in patients with atrial fibrillation

Atrial fibrosis can present as an arrhythmogenic substrate that is correlated with higher recurrence after catheter ablation for atrial fibrillation. Galectin-3, a beta-galactoside-binding lectin, is highly expressed and secreted from macrophages and is important in inflammation and fibrosis. We assessed the clinical implications of serum galectin-3 in patients with atrial fibrillation. This was a prospective cohort study of consecutive patients who underwent radiofrequency catheter ablation in a tertiary referral center from February 2017 to September 2017. Intracardiac blood sampling, echocardiographic measurements, magnetic resonance imaging with late gadolinium enhancement, electrophysiologic testing, and endocardial voltage mapping were consistently implemented in 75 patients before the ablation. Serum galectin-3 level was higher in patients with diabetes mellitus and was correlated with values that indicated the left atrial size. During a median 14 months of follow-up, atrial tachyarrhythmia recurred in 27% of patients. In multivariable Cox regression analysis, non-paroxysmal atrial fibrillation (hazard ratio 6.8; 95% confidence interval 1.6–28.9) and higher galectin-3 levels (hazard ratio 1.3; 95% confidence interval 1.0–1.7) were associated with increased risk of recurrence. Serum galectin-3 may be a prognostic biomarker for risk stratification in patients with atrial fibrillation planned catheter ablation.

Evaluating the Role of Galectins in Clathrin-Independent Endocytosis

Galectin-3 is a chimeric galectin involved in diverse intracellular and extracellular functions. Galectin-3 is synthesized in the cytoplasm and then released extracellularly by a poorly understood non-canonical secretion mechanism. As a result, it can play important roles both inside and outside the cell. One important extracellular role of galectin-3 is in modulating clathrin-independent endocytosis (CIE), a form of cellular internalization that is still not well understood. CIE, unlike clathrin-mediated endocytosis, has neither defined signaling sequences nor cytoplasmic machinery. As a result, extracellular interactions like the galectin-glycan interactions are thought to directly drive changes in CIE. This chapter discusses the methods designed to study the role of galectin-glycan interactions in CIE, which have provided us with insight into the functions of galectin-3 and cell surface glycans during CIE cargo internalization. These methods include media supplementation for metabolic glycoengineering, antibody internalization assays, lectin panels to assay changes in glycan patterns, exogenous galectin-3 supplementation, galectin-3 secretion assays, and in vitro assays to monitor the effect of galectins on CIE.

Increased Circulating Levels of Galectin Proteins in Patients with Breast, Colon, and Lung Cancer

Galectins are proteins with high-affinity β-galactoside-binding sites that function in a variety of signaling pathways through interactions with glycoproteins. The known contributions of galectins-1, -3, -7, -8, and -9 to angiogenesis, metastasis, cell division, and evasion of immune destruction led us to investigate the circulating levels of these galectins in cancer patients. This study compares galectin concentrations by enzyme-linked immunosorbent assay (ELISA) from each stage of breast, lung, and colon cancer. Galectins-1 and -7, which share a prototype structure, were found to have statistically significant increases in breast and lung cancer. Of the tandem-repeat galectins, galectin-8 showed no statistically significant change in these cancer types, but galectin-9 was increased in colon and lung cancer. Galectin-3 is the only chimera-type galectin and was increased in all stages of breast, colon, and lung cancer. In conclusion, there were significant differences in the galectin levels in patients with these cancers compared with healthy controls, and galectin levels did not significantly change from stage to stage. These findings suggest that further research on the roles of galectins early in disease pathogenesis may lead to novel indications for galectin inhibitors.

The Role of Galectin-3 and ST2 in Cardiology: A Short Review

Galectin-3 is a lectin that binds beta-galactosides. It is involved in cardiac remodeling and fibrosis through the activation of macrophages and fibroblasts. ST2 is secreted by myocardial cells due to cardiac overload. These two biomarkers have been traditionally studied in the field of heart failure to guide medical therapy and detect the progression of the disease. Nevertheless, there are novel evidences that connect galectin-3 and ST2 with coronary heart disease and, specifically, with atrial fibrillation. The aim of this article is to concisely review the diagnostic and prognostic role of galectin-3 and ST2 in different cardiac diseases.

Analysis of the Correlation of Galectin-3 Concentration with the Measurements of Echocardiographic Parameters Assessing Left Atrial Remodeling and Function in Patients with Persistent Atrial Fibrillation

Galectin-3 (gal-3) is a fibrosis marker and may play a role in fibrosis of the left atrium (LA). Left atrial wall fibrosis may influence the transition from paroxysmal to non-paroxysmal atrial fibrillation (AF). In this study, we assessed the correlation of gal-3 concentration with the main echocardio-graphic parameters evaluating dimensions, volume, compliance, and left atrial contractility during AF and after successful electrical cardioversion (DCCV). The study included 63 patients with left atrial enlargement who qualified for DCCV due to persistent AF. The procedure recovered sinus rhythm in 43 (68.3%) patients. The concentration of gal-3 was negatively correlated with the echocardiographic parameters of LA including dimensions (LA length pre, rho = −0.38; p = 0.003), volume (LAV pre, rho = −0.39; p = 0.003), compliance (LASr mean post, rho = −0.33) and contractility (pLASRct mean post, rho = −0.33; p = 0.038). Negative correlations of gal-3 concentration were also observed in relation to the volume and contractility of the left ventricle. The concentration of gal-3 significantly negatively correlates with the size, systolic function, and compliance of the LA wall in patients with persistent AF. Determining gal-3 concentration in patients with persistent AF may help in the assessment of remodeling of the LA wall.

Personalized monitoring of electrical remodelling during atrial fibrillation progression via remote transmissions from implantable devices

Aims

Atrial electrical remodelling (AER) is a transitional period associated with the progression and long-term maintenance of atrial fibrillation (AF). We aimed to study the progression of AER in individual patients with implantable devices and AF episodes.

Methods and results

Observational multicentre study (51 centres) including 4618 patients with implantable cardioverter-defibrillator +/−resynchronization therapy (ICD/CRT-D) and 352 patients (2 centres) with pacemakers (median follow-up: 3.4 years). Atrial activation rate (AAR) was quantified as the frequency of the dominant peak in the signal spectrum of AF episodes with atrial bipolar electrograms. Patients with complete progression of AER, from paroxysmal AF episodes to electrically remodelled persistent AF, were used to depict patient-specific AER slopes. A total of 34 712 AF tracings from 830 patients (87 with pacemakers) were suitable for the study. Complete progression of AER was documented in 216 patients (16 with pacemakers). Patients with persistent AF after completion of AER showed ∼30% faster AAR than patients with paroxysmal AF. The slope of AAR changes during AF progression revealed patient-specific patterns that correlated with the time-to-completion of AER (R² = 0.85). Pacemaker patients were older than patients with ICD/CRT-Ds (78.3 vs. 67.2 year olds, respectively, P < 0.001) and had a shorter median time-to-completion of AER (24.9 vs. 93.5 days, respectively, P = 0.016). Remote transmissions in patients with ICD/CRT-D devices enabled the estimation of the time-to-completion of AER using the predicted slope of AAR changes from initiation to completion of electrical remodelling (R² = 0.45).

Conclusion

The AF progression shows patient-specific patterns of AER, which can be estimated using available remote-monitoring technology.

Potential Biomarkers in Atrial Fibrillation: Insight into their Clinical Significance

ABSTRACT

In risk-stratifying patients with atrial fibrillation (AF), physicians rely heavily on clinical parameters that provide risk scores and determine treatment strategies. There has been increasing research on potential biomarkers in the blood that could more accurately determine both risk of complications in AF and risk of incidence of AF. This review highlights the clinical significance of five novel biomarkers that have been shown to be linked to AF. These biomarkers are carbohydrate antigen 125 (CA-125), galectin-3 (gal-3), growth differentiating factor-15 (GDF-15), a member of the interleukin 1 receptor family, IL1RL1 (ST2) and N-terminal pro B-type natriuretic peptide (NT-proBNP).

Transcriptome and proteome mapping in the sheep atria reveal molecular featurets of atrial fibrillation progression

AIMS

Atrial fibrillation (AF) is a progressive cardiac arrhythmia that increases the risk of hospitalization and adverse cardiovascular events. There is a clear demand for more inclusive and large-scale approaches to understand the molecular drivers responsible for AF, as well as the fundamental mechanisms governing the transition from paroxysmal to persistent and permanent forms. In this study, we aimed to create a molecular map of AF and find the distinct molecular programmes underlying cell type-specific atrial remodelling and AF progression.

METHODS AND RESULTS

We used a sheep model of long-standing, tachypacing-induced AF, sampled right and left atrial tissue, and isolated cardiomyocytes (CMs) from control, intermediate (transition), and late time points during AF progression, and performed transcriptomic and proteome profiling. We have merged all these layers of information into a meaningful three-component space in which we explored the genes and proteins detected and their common patterns of expression. Our data-driven analysis points at extracellular matrix remodelling, inflammation, ion channel, myofibril structure, mitochondrial complexes, chromatin remodelling, and genes related to neural function, as well as critical regulators of cell proliferation as hallmarks of AF progression. Most important, we prove that these changes occur at early transitional stages of the disease, but not at later stages, and that the left atrium undergoes significantly more profound changes than the right atrium in its expression programme. The pattern of dynamic changes in gene and protein expression replicate the electrical and structural remodelling demonstrated previously in the sheep and in humans, and uncover novel mechanisms potentially relevant for disease treatment.

CONCLUSIONS

Transcriptomic and proteomic analysis of AF progression in a large animal model shows that significant changes occur at early stages, and that among others involve previously undescribed increase in mitochondria, changes to the chromatin of atrial CMs, and genes related to neural function and cell proliferation.

Optimising Large Animal Models of Sustained Atrial Fibrillation: Relevance of the Critical Mass Hypothesis

BACKGROUND

Large animal models play an important role in our understanding of the pathophysiology of atrial fibrillation (AF). Our aim was to determine whether prospectively collected baseline variables could predict the development of sustained AF in sheep, thereby reducing the number of animals required in future studies. Our hypothesis was that the relationship between atrial dimensions, refractory periods and conduction velocity (otherwise known as the critical mass hypothesis) could be used for the first time to predict the development of sustained AF.

METHODS

Healthy adult Welsh mountain sheep underwent a baseline electrophysiology study followed by implantation of a neurostimulator connected via an endocardial pacing lead to the right atrial appendage. The device was programmed to deliver intermittent 50 Hz bursts of 30 s duration over an 8-week period whilst sheep were monitored for AF.

RESULTS

Eighteen sheep completed the protocol, of which 28% developed sustained AF. Logistic regression analysis showed only fibrillation number (calculated using the critical mass hypothesis as the left atrial diameter divided by the product of atrial conduction velocity and effective refractory period) was associated with an increased likelihood of developing sustained AF (Ln Odds Ratio 26.1 [95% confidence intervals 0.2-52.0] p = 0.048). A receiver-operator characteristic curve showed this could be used to predict which sheep developed sustained AF (C-statistic 0.82 [95% confidence intervals 0.59-1.04] p = 0.04).

CONCLUSION

The critical mass hypothesis can be used to predict sustained AF in a tachypaced ovine model. These findings can be used to optimise the design of future studies involving large animals.

Plasma Galectin-3 is associated with progression from paroxysmal to persistent atrial fibrillation

Background

Galectin-3 (Gal-3) is currently recognized as a promising biomarker for myocardial fibrosis. This study aimed to explore the potential association between plasma Gal-3 concentrations and atrial fibrillation (AF) progression in paroxysmal AF (PAF) patients

Methods

A total of 213 PAF patients were included for analysis in this study. All peripheral blood samples were prospectively collected and stored at -80℃ for subsequent Gal-3 quantification. The AF progression was defined as transformation from PAF to persistent AF (PsAF).

Results

A total of 51 PAF patients progressed to PsAF during a mean follow-up period of 674.44 ± 19.48 days. Patients with AF progression had significantly higher baseline plasma Gal-3 concentrations than those stayed in PAF status (13.52 ± 0.94 vs. 7.93 ± 0.37, p < 0.001). All PAF patients were divided into two subgroups based on the median value of plasma Gal-3 concentrations. Kaplan–Meier curve analysis showed a significantly higher AF progression rate in the higher plasma Gal-3 concentration group (log-rank test p < 0.001). In the Cox regression analysis, plasma Gal-3 concentration and left atrial diameter (LAD) were showed significantly associated with AF progression, even after adjustment of other potential confounding risk factors. Discrimination for AF progression with a simple model which consists of plasma Gal-3 concentration and LAD was modest with a C-statistic 0.72 (95%CI 0.64–0.80). Plasma Gal-3 concentration significantly improved the predictability by appropriately reclassifying several patients with progression (NRI = 28.3%, p = 0.003).

Conclusion

Elevated plasma Gal-3 concentration is significantly associated with AF progression from PAF to PsAF. Plasma Gal-3 concentration could be used for PAF progression risk stratification and guiding management for PAF patients.

The common characteristics and mutual effects of heart failure and atrial fibrillation: initiation, progression, and outcome of the two aging-related heart diseases

Atrial fibrillation (AF) and heart failure (HF) are common chronic diseases noted in humans. AF and HF share several risk factors, such as age, hypertension, obesity, diabetes, and dyslipidemia. They can interact with each other, while both their morbidity and mortality have been considerably increased. And AF and HF often occur together, suggesting a strong association between the two. However, the underlying mechanism behind this association is not well understood. Among them, aging is the most significant common risk factor, which represents an aging heart and is characterized by fibrosis and decreased number of cardiomyocytes, known as senescence-related cardiac remodeling for both atria and ventricles. Finally, it is proposed that cardiac remodeling is the key link between AF and HF.

Evaluation of Galectin-3 Plasma Concentration in Adolescents with Ventricular Arrhythmia

Galectin-3 (G3) is a biomarker known as an inflammatory state exponent. The aim of this paper was to analyze the G3 in adolescents with ventricular arrhythmia (VES) in order to evaluate its impact on myocardial tissue preservation. The study group (SG) consisted of 25 VES adolescents. The control group (CG) was 21 healthy children. G3 was assessed in the SG and CG. In the SG electrocardiography, Holter monitoring, echocardiography and CMR were performed. The G3 in SG was 13.45 ± 11.4 ng/mL and in CG 7.2 ± 2.0 ng/mL, p < 0.001. Moderate positive correlation between the G3 and z-score of the left ventricular diameter (r = 0.47, p = 0.041) and moderate negative correlation between the G3 and the left ventricular ejection fraction in cardiac magnetic resonance (CMR EF) (-0.49, p = 0.032) were found. According to the multiple linear regression analysis, CMR EF and VES were independent predictors for G3 elevation. Conclusion: Galectin-3 plasma concentration is elevated and correlates with the chosen left ventricular dysfunction parameters in adolescents suffering from ventricular arrhythmia. Further investigation is necessary to establish if elevated G3 is a useful biomarker for screening young individuals with ventricular arrhythmia who are at risk of structural cardiovascular pathology.

Implications of Inflammation and Fibrosis in Atrial Fibrillation Pathophysiology

Inflammation and fibrosis have been implicated in the pathophysiology of atrial fibrillation. Atrial fibrosis causes conduction disturbances and is a central component of atrial remodeling in atrial fibrillation. Cardiac fibroblasts, the cells responsible for fibrosis formation, are activated by inflammatory mediators and growth factors associated with systemic inflammatory conditions. Thus, inflammation contributes to atrial fibrosis; the complex interplay of these maladaptive components creates a vicious cycle of atrial remodeling progression, maintaining atrial fibrillation and increasing thrombogenicity. This review provides up-to-date knowledge regarding inflammation and fibrosis in atrial fibrillation pathophysiology and their potential as therapeutic targets.

Novel biomarkers in cardiovascular surgery

Cardiovascular disease includes health problems related to the heart, arteries and veins and is a significant healthcare problem worldwide. Cardiovascular disease may be acute or chronic and relapses are frequent. Biomarkers involved in this field may help clinicians and surgeons in diagnosis and adequate decision making. Relevant articles searched in the following databases Medline, Scopus, ScienceDirect, were retrieved and analysed. Several biomarkers have been identified and we analyzed those of most importance from a clinical and surgical point of view. Biomarkers can better identify high-risk individuals, facilitate follow-up process, provide information regarding prognosis and better tailor the most appropriate surgical treatment.

Left atrial fibrosis in atrial fibrillation: Mechanisms, clinical evaluation and management

Atrial fibrillation (AF), the commonest arrhythmia, shows associations with various disease conditions. Mounting evidence indicates that atrial fibrosis is an important part of the arrhythmogenic substrate, with an essential function in the generation of conduction abnormalities that underlie the transition from paroxysmal to persistent AF, which in turn contributes to AF perpetuation. Left atrial (LA) fibrosis is considered a possible major factor and predictor in AF treatment. The present review provides insights into LA fibrosis’ association with AF. The information is focused on clinical aspects and mechanisms, clinical evaluating methods that evaluate fibrosis changes and examining possible options for the prevention of atrial fibrosis.

Role of NLRP3-Inflammasome/Caspase-1/Galectin-3 Pathway on Atrial Remodeling in Diabetic Rabbits

Both diabetes mellitus (DM) and atrial fibrillation (AF) are usually associated with enhanced inflammatory response. The effect of the "NACHT, LRR and PYD domain containing protein 3" (NLRP3)-inflammasome/caspase-1/galectin-3 pathway and the potential benefits of NLRP3-inflammasome inhibitor glibenclamide (GLB) on atrial remodeling in the DM state are still unknown. Here, we demonstrated that higher AF inducibility and conduction inhomogeneity, slower epicardial conduction velocity, and increased amount of fibrosis in diabetic rabbits as against normal ones were markedly reduced by GLB. Atrial caspase-1 activity as well as serum IL-1β and IL-18 levels were elevated in diabetic animals but suppressed by GLB. Moreover, GLB decreased the DM-induced protein expression enhancement of NLRP3, Gal-3, TGF-β1, and CaV1.2 according to western blot analysis. Summarily, our findings indicate that the NLRP3-inflammasome/caspase-1/Gal-3 signaling pathway is related to the pathogenesis of AF in the diabetic state. NLRP3-inflammasome inhibitor GLB prevents AF inducibility and moderates atrial structural remodeling in DM.