ABSTRACT: MicroRNA sequencing of myocardium of ovine comparing normal (Control), paced-induced heart failure (HF) and heart failure recovery (HF-R) after discontinuation of pacing.
Project description:MicroRNA profiling of myocardium of ovine comparing normal (Control), paced-induced heart failure (HF) and heart failure recovery (HF-R) after discontinuation of pacing.
Project description:We have used chronic cardiac pacing in conscious dogs to study mechanism related to the development of dilated cardiomyopathy and the transition from compensated dysfunction (CD) to decompensated heart failure (HF). This occurs from the 3rd to 4th week of pacing with end-stage HF at 30?1 days. Keywords: disease state analysis
Project description:Canine tachycardia-induced cardiomyopathy caused by several weeks of rapid ventricular pacing is a well-established animal model of congestive heart failure. However, little is known about the underlying changes in gene expression that occur in the canine myocardium after the induction of heart failure. This project aims to compare expression profiles in left ventricular free wall samples from control dogs and dogs with pacing-induced heart failure on the custom MuscleChip. Keywords: other
Project description:Gene expression in right atrial myocardium was compared between non-failing control and tachypaced dogs (heart failure was induced by tachycardic pacing for 6 weeks).
Project description:Objectives: To test whether (1) electromechanical dyssynchrony induces region-specific alterations in the myocardial transcriptome and (2) dyssynchrony-induced gene expression changes can be corrected by cardiac resynchronization (CRT). Background: To date, CRT is the only heart failure treatment that can both acutely and chronically increase systolic function and prolong survival, something not yet achieved by a drug therapy. However, the mechanisms underlying the benefits of CRT remain elusive. Methods: Adult dogs underwent left bundle branch ablation (LBBB) and right atrial pacing at 200 bpm for either 6 weeks (dyssynchronous heart failure, DHF, n=12) or 3 weeks followed by 3 weeks of resynchronization by bi-ventricular pacing at the same pacing rate (CRT, n=10). Control animals without LBBB were not paced (NF, n=14). Echocardiography and invasive hemodynamic measurements were performed at 3 and 6 weeks. At 6 weeks, RNA was isolated from the anterior and lateral LV walls and hybridized onto canine-specific 44K microarrays. Results: In DHF, transcriptional changes consistent with re-expression of a fetal gene program were primarily observed in the anterior LV, resulting in increased regional heterogeneity of gene expression within the left ventricle. Dyssynchrony-induced region-specific expression changes in 1050 transcripts were reversed by CRT to levels of NF hearts (false discovery rate <5%). CRT remodeled transcripts with metabolic and cell signaling function and greatly reduced regional heterogeneity of gene expression compared with DHF. Conclusions: Our results demonstrate a profound effect of electromechanical dyssynchrony on the regional cardiac transcriptome, causing gene expression changes primarily in the anterior LV wall. CRT corrected the alterations in gene expression in the anterior wall by reversing the fetal gene expression pattern, supporting a global effect of biventricular pacing on the ventricular transcriptome that extends beyond the pacing site in the lateral wall. Designed as a 1-color experiments, samples from anterior and lateral left ventricular myocardium from non-failing, DHF and CRT animals were labeled with Cy3 and hybridized onto Agilent 44K long oligonucleotide arrays.
Project description:Spontaneous paroxysmal atrial fibrillation (PAF) is one of the very common heart rhythm disorders. The molecular mechanisms underlying PAF susceptibility and persistence are multiple and incompletely understood. To study the contribution of microRNAs (miRNAs) to the development and perpetuation of PAF, we used microarray/qPCR analyses to search for changes in miRNA expression in atrial myocardium upon pacing-induced PAF. The miRNA microarray analysis was performed at LC Sciences (Houston, TX, USA). Following screening-microarray, several miRNAs were selected for detailed real-time qPCR assay. Our results suggest that immediate-early miR remodeling of LAA underlies the development and persistence of PAF. A closed-chest model of PAF was established in postnatal pigs via a rapid atrial electrical stimulation with a controlled ventricular response rate. A pacing catheter (delivered into the right atrium via femoral vein access under fluoroscopic guidance) was connected with an external pulse generator for programmed pacing rates. The burst-pacing stimuli were repeated several times, and the induced PAF occurrence rates and durations were recorded. Burst pacing was not performed in sham-operated group. Animals were euthanized 24 hours after cessation of pacing. Given that the right atrium might have been damaged by catheter insertion, we studied miRNA expression changes associated with PAF in the left atrial appendage (LAA) from paced vs control pigs. Six piglet were randomized in two groups, the PAF group (3 replicates) and the sham-control group (3 replicates)
Project description:Analysis of changes of gene expression profiles in the left ventricle (LV) during the progression of heart failure (HF) in the canine tachypacing induced HF model. Gene expression profiling was performed on samples collected at different time points representing various stages of LV dysfunction, i.e. tachypaced for 3 days (Day-3), 1 week (Week-1), 2 weeks (Week-2), 3-4 weeks (End stage), and unpaced controls (Day-0). Results provide insights into molecular mechanisms of heart failure progression. Keywords: time course This work aims to study changes of gene expression profiles in the left ventricle (LV) during the progression of heart failure (HF) in the canine tachypacing induced HF model. LV transmural tissue sections were collected at different time points after initiating rapid pacing representing various stages of LV dysfunction, i.e. tachypaced for 3 days (Day-3), 1 week (Week-1), 2 weeks (Week-2), 3-4 weeks (End stage), and unpaced controls (Day-0). As biological replicates, tissues were collected separately from 3 individual dogs at each of the time points. In total we collected 15 tissue samples for all 5 time points. Three RNA samples were independently isolated from each of the 15 tissue samples as technical replicates. The resulting 45 RNA samples were used for microarray experiment. Affymetrix gene expression profiles of the 45 RNA samples were used for all data analysis in this study.
Project description:Objectives: To test whether (1) electromechanical dyssynchrony induces region-specific alterations in the myocardial transcriptome and (2) dyssynchrony-induced gene expression changes can be corrected by cardiac resynchronization (CRT). Background: To date, CRT is the only heart failure treatment that can both acutely and chronically increase systolic function and prolong survival, something not yet achieved by a drug therapy. However, the mechanisms underlying the benefits of CRT remain elusive. Methods: Adult dogs underwent left bundle branch ablation (LBBB) and right atrial pacing at 200 bpm for either 6 weeks (dyssynchronous heart failure, DHF, n=12) or 3 weeks followed by 3 weeks of resynchronization by bi-ventricular pacing at the same pacing rate (CRT, n=10). Control animals without LBBB were not paced (NF, n=14). Echocardiography and invasive hemodynamic measurements were performed at 3 and 6 weeks. At 6 weeks, RNA was isolated from the anterior and lateral LV walls and hybridized onto canine-specific 44K microarrays. Results: In DHF, transcriptional changes consistent with re-expression of a fetal gene program were primarily observed in the anterior LV, resulting in increased regional heterogeneity of gene expression within the left ventricle. Dyssynchrony-induced region-specific expression changes in 1050 transcripts were reversed by CRT to levels of NF hearts (false discovery rate <5%). CRT remodeled transcripts with metabolic and cell signaling function and greatly reduced regional heterogeneity of gene expression compared with DHF. Conclusions: Our results demonstrate a profound effect of electromechanical dyssynchrony on the regional cardiac transcriptome, causing gene expression changes primarily in the anterior LV wall. CRT corrected the alterations in gene expression in the anterior wall by reversing the fetal gene expression pattern, supporting a global effect of biventricular pacing on the ventricular transcriptome that extends beyond the pacing site in the lateral wall. Complementary study to GSE14327. While GSE14327 was designed as a 1-color microarray experiment, this series was carried out following a 2-color design (anterior and lateral LV wall labeled with Cy3 and Cy5, respectively, including dye swaps).
Project description:Spontaneous paroxysmal atrial fibrillation (PAF) is one of the very common heart rhythm disorders. The molecular mechanisms underlying PAF susceptibility and persistence are multiple and incompletely understood. To study the contribution of microRNAs (miRNAs) to the development and perpetuation of PAF, we used microarray/qPCR analyses to search for changes in miRNA expression in atrial myocardium upon pacing-induced PAF. The miRNA microarray analysis was performed at LC Sciences (Houston, TX, USA). Following screening-microarray, several miRNAs were selected for detailed real-time qPCR assay. Our results suggest that immediate-early miR remodeling of LAA underlies the development and persistence of PAF. A closed-chest model of PAF was established in postnatal pigs via a rapid atrial electrical stimulation with a controlled ventricular response rate. A pacing catheter (delivered into the right atrium via femoral vein access under fluoroscopic guidance) was connected with an external pulse generator for programmed pacing rates. The burst-pacing stimuli were repeated several times, and the induced PAF occurrence rates and durations were recorded. Burst pacing was not performed in sham-operated group. Animals were euthanized 24 hours after cessation of pacing. Given that the right atrium might have been damaged by catheter insertion, we studied miRNA expression changes associated with PAF in the left atrial appendage (LAA) from paced vs control pigs.
Project description:Objectives: To test whether (1) electromechanical dyssynchrony induces region-specific alterations in the myocardial transcriptome and (2) dyssynchrony-induced gene expression changes can be corrected by cardiac resynchronization (CRT). Background: To date, CRT is the only heart failure treatment that can both acutely and chronically increase systolic function and prolong survival, something not yet achieved by a drug therapy. However, the mechanisms underlying the benefits of CRT remain elusive. Methods: Adult dogs underwent left bundle branch ablation (LBBB) and right atrial pacing at 200 bpm for either 6 weeks (dyssynchronous heart failure, DHF, n=12) or 3 weeks followed by 3 weeks of resynchronization by bi-ventricular pacing at the same pacing rate (CRT, n=10). Control animals without LBBB were not paced (NF, n=14). Echocardiography and invasive hemodynamic measurements were performed at 3 and 6 weeks. At 6 weeks, RNA was isolated from the anterior and lateral LV walls and hybridized onto canine-specific 44K microarrays. Results: In DHF, transcriptional changes consistent with re-expression of a fetal gene program were primarily observed in the anterior LV, resulting in increased regional heterogeneity of gene expression within the left ventricle. Dyssynchrony-induced region-specific expression changes in 1050 transcripts were reversed by CRT to levels of NF hearts (false discovery rate <5%). CRT remodeled transcripts with metabolic and cell signaling function and greatly reduced regional heterogeneity of gene expression compared with DHF. Conclusions: Our results demonstrate a profound effect of electromechanical dyssynchrony on the regional cardiac transcriptome, causing gene expression changes primarily in the anterior LV wall. CRT corrected the alterations in gene expression in the anterior wall by reversing the fetal gene expression pattern, supporting a global effect of biventricular pacing on the ventricular transcriptome that extends beyond the pacing site in the lateral wall.