Project description:Accumulating studies have suggested that epicardial adipose tissue play an important role in the pathogenesis of atrial fibrillation (AF), but few have characterized the underlying mechanism between their interactions. Recent evidence suggested that bioactive molecules secreted from EAT, including exosomes carrying non-coding RNAs, may modulate atrial remodeling. The aim of the present study was to investigate the expression profile of mRNAs and ncRNAs in EAT with AF.
Project description:Atrial fibrillation (AF) is the most common sustained arrythmia, but the potential molecular indicators involved in structural and electronical remodeling remains to be clarified. Epicardial adipose tissue (EAT), a visceral fat depot surrounding the heart, is increasingly recognized to be metabolically active and has been proposed with an arrthymogenicity nature. It is able to secret a myriad of bioactive molecules, including exosomes carrying tRNA derived small RNAs (tsRNAs). Accumulating findings have suggested that these specific tsRNAs dynamically impact fundamental cellular processes, but there are no studies discovering the association between tsRNAs of EAT and AF, and their interactions and potential signaling pathways remain to be elucidated.
Project description:Aims: We tested the hypothesis that central-marginal dispersion in adipocyte diameter in epicardial adipose tissue (EAT) would represent fibrotic remodelling of EAT, a crucial state to promote atrial myocardial fibrosis to form a substrate of atrial fibrillation (AF). We also investigated whether the central-marginal EAT density ratio by the analyses of computed tomographic (CT) imaging could predict the central-marginal adipocyte diameter ratio in EAT. Methods and results: Left atrial appendage samples were obtained from 76 consecutive AF patients during cardiovascular surgery. EAT at central area (Central EAT) and that adjacent to atrial myocardium (Marginal EAT) were evaluated. Compared to the Central EAT, the dimeter of adipocytes was smaller, fibrotic remodeling of EAT (EAT fibrosis) was more severe, and the infiltration of CD3-, CD68-, or α-SMA-positive cells were more abundant in the Marginal EAT. EAT fibrosis positively correlated with adipocyte diameter in the Central EAT, while it negatively correlated with that in the Marginal EAT, resulting in the tightly positive correlation between EAT fibrosis and the ratio of central to marginal adipocyte diameter (C/M diameter ratio) (r=0.73, p<0.01). The C/M diameter ratio was greater in patients with persistent AF (PeAF) than in those with paroxysmal AF (PAF) (p<0.01). The CT density in Central EAT and Marginal EAT was measured and their ratio (C/M density ratio) was calculated. The C/M density ratio correlated tightly with the C/M diameter ratio (r=0.69, p<0.01). Conclusion: Our results suggest that C/M adipocyte diameter ratio was associated with fibrotic remodeling of EAT and progression of AF. Our results also suggest that C/M adipocyte diameter ratio could be accurately predicted by the analyses of CT findings noninvasively.
Project description:Electrical and structural remodeling processes are contributors to the self-perpetuating nature of atrial fibrillation (AF). However, their correlation has not been clarified. In this study, human atrial tissues from the patients with rheumatic mitral valve disease in either sinus rhythm or persistent AF were analyzed using a combined transcriptomic and proteomic approach. An up-regulation in chloride intracellular channel (CLIC) 1, 4, 5 and a rise in type IV collagen were revealed. Combined with the results from immunohistochemistry and electron microscope analysis, the distribution of type IV collagen and effects of fibrosis on myocyte membrane indicated the possible interaction between CLIC and type IV collagen, confirmed by protein structure prediction and co-immunoprecipitation. These results indicate that CLICs play an important role in the development of atrial fibrillation and that CLICs and structural type IV collagen may interact on each other to promote the development of AF in rheumatic mitral valve disease.
Project description:Introduction: Post-operative atrial fibrillation (POAF) is a frequent complication after cardiac surgery, but its pathophysiology remains incompletely understood. Considering that epicardial adipose tissue (EAT) is in close vicinity with the atrial myocardium, we hypothesized that a specific pre-operative EAT phenotype would be associated to POAF onset following surgery. Methods: Patients undergoing cardiac surgery prospectively enrolled in the POMI-AF cohort between February 2016 and June 2017 were studied. EAT samples were collected at the beginning of surgery. Whole-tissue gene expression patterns and the stromal and vascular fraction (SVF) cellular composition were explored. Patients were followed after surgery by continuous ECG to detect POAF onset. Results: Among the 60 patients included in the cohort, 15 POAF and 15 non-POAF patients were matched based on pre-operative characteristics. Gene set enrichment analysis of transcriptomic data from pre-operative EAT samples revealed 40 enriched biological processes in POAF vs non-POAF patients. Most of these processes were related to cellular immune response. Leukocytes (63±15% of total cells), and more specifically lymphocytes (56±13% of total CD45+ cells), represented the major cell subset in the preoperative EAT SVF, with no quantitative differences between POAF and SR patients (76 [52; 84]% vs 56 [50; 64]%, p=0.22). However, POAF patients presented a significantly higher cytotoxic CD8+/helper CD4+ T lymphocyte ratio than SR patients (respectively, 0.69[0.55; 1.19] vs 0.50 [0.31; 0.54], p=0.03) suggesting a cytotoxic shift prior to surgery. Conclusion: Epicardial fat from patients who develop POAF displays a specific pre-operative transcriptome signature characteristic of cellular immune response and cytotoxic lymphocyte enrichment.
Project description:This study will report the incidence of atrial fibrillation after elective colorectal cancer resection in the over 65 age group. This will be used to validate a risk model for the development of post-operative atrial fibrillation.
Eligible patients will undergo electrocardiogram based screening for atrial fibrillation, as well as brain natriuretic peptide tests prior to surgery. They will undergo 24 hour holter monitor prior to surgery, and at 30 and 90 days following surgery.
The primary outcome will be occurrence of atrial fibrillation within 90 days of surgery. Secondary outcomes include quality of life change, use of hospital services for atrial fibrillation, and complications of atrial fibrillation. This will be used to validate the pre-existing model for prediction of atrial fibrillation.
Project description:To identify pathway and mechanism undergoing post operative atrial fibrillation, we check transcriptomic expression of patients with and without post operative atrial fibrillation development and compare up and down regulated genes and their pathways. Right atrial appendage were obtained from patients undergoing cardiac surgery.
Project description:GSE2240 contains two different experimental subsets: 1) Comparison of atrial and ventricular gene expression (atrial tissue of patients with sinus rhythm vs. human left ventricular non-failing myocardium) The purpose of our investigation was to identify the transcriptional basis for ultrastructural and functional specialization of human atria and ventricles. Using exploratory microarray analysis (Affymetrix U133A+B), we detected 11,740 transcripts expressed in human heart, representing the most comprehensive report of the human myocardial transcriptome to date. Variation in gene expression between atria and ventricles accounted for the largest differences in this data set, as 3.300 and 2.974 transcripts showed higher expression in atria and ventricles, respectively. Functional classification based on Gene Ontology identified chamber-specific patterns of gene expression and provided molecular insights into the regional specialization of cardiomyocytes, correlating important functional pathways to transcriptional activity: Ventricular myocytes preferentially express genes satisfying contractile and energetic requirements, while atrial myocytes exhibit specific transcriptional activities related to neurohumoral function. In addition, several pro-fibrotic and apoptotic pathways were concentrated in atrial myocardium, substantiating the higher susceptibility of atria to programmed cell death and extracellular matrix remodelling observed in human and experimental animal models of heart failure. Differences in transcriptional profiles of atrial and ventricular myocardium thus provide molecular insights into myocardial cell diversity and distinct region-specific adaptations to physiological and pathophysiological conditions (Barth AS et al., Eur J Physiol, 2005). 2) Comparison of atrial gene expression in patients with permanent atrial fibrillation and sinus rhythm. Atrial fibrillation is associated with increased expression of ventricular myosin isoforms in atrial myocardium, regarded as part of a dedifferentiation process. Whether re-expression of ventricular isoforms in atrial fibrillation is restricted to transcripts encoding for contractile proteins is unknown. Therefore, this study compares atrial mRNA expression in patients with permanent atrial fibrillation to atrial mRNA expression of patients with sinus rhythm as well as to ventricular gene expression using Affymetrix U133 arrays. In atrial myocardium, we identified 1.434 genes deregulated in atrial fibrillation, the majority of which, including key elements of calcium-dependent signaling pathways, displayed down-regulation. Functional classification based on Gene Ontology provided the specific gene sets of the interdependent processes of structural, contractile and electrophysiological remodeling. In addition, we demonstrate for the first time a prominent up-regulation of transcripts involved in metabolic activities, suggesting an adaptive response to an increased metabolic demand in fibrillating atrial myocardium. Ventricular-predominant genes were five times more likely to be up-regulated in atrial fibrillation (174 genes up-regulated, 35 genes down-regulated), while atrial-specific transcripts were predominantly down-regulated (56 genes up-regulated, 564 genes down-regulated). Overall, in atrial myocardium, functional classes of genes characteristic of ventricular myocardium were found to be up-regulated (e.g. metabolic processes) while functional classes predominantly expressed in atrial myocardium were down-regulated in atrial fibrillation (e.g. signal transduction and cell communication). Therefore, dedifferentiation with adoption of a ventricular-like signature is a general feature of the fibrillating atrium, uncovering the transcriptional response pattern in pmAF (Barth AS et al., Circ Res, 2005). Keywords = human myocardium Keywords = atrial fibrillation Keywords = sinus rhythm Keywords = left ventricular gene expression Keywords: other
Project description:Atrial fibrillation (AF) is the most common heart arrhythmia disease. The greatest risk of atrial fibrillation is stroke, and stroke caused by valvular heart disease with atrial fibrillation (AF-VHD) is more serious. the development mechanism from VHD to AF-VHD is not yet clear. The research on expression profiles of lncRNA and mRNA is helpful to explore molecular mechanism in patients with valvular heart disease who develop atrial fibrillation.