Project description:BackgroundPediatric pulmonary hypertension is a severe disease defined by sustained elevation of pulmonary artery pressures and pulmonary vascular resistance (PVR). Noninvasive diagnostic and prognostic markers that are more pulmonary vascular specific have been elusive because of disease heterogeneity and patient growth.Research questionIs soluble suppressor of tumorigenicity (ST2) associated with pulmonary hemodynamic and functional changes in pediatric pulmonary hypertension? Does ST2 improve mortality risk models in pediatric pulmonary hypertension?Study design and methodsTwo pediatric cohorts (age < 21 years) were assayed for ST2 and N-terminal prohormone B-natriuretic peptide: a cross-sectional cohort from the National Heart Lung and Blood Institute-funded National Biological Sample and Data Repository for PAH (PAHB) (N = 182), and a second longitudinal cohort from Children's Hospital of Colorado (N = 61). Adjusted linear regression was used for association with clinical variables. Clinical mortality models (the Registry to Evaluate Early and Long-Term PAH Disease Management [REVEAL] score) with and without ST2 were used to predict worsening outcomes and compared. Pulmonary artery endothelial and smooth muscle cell ST2 expression and secretion were assayed in vitro.ResultsIn an adjusted (age and sex) analysis in the PAHB, ST2 was significantly associated with shorter 6-min walk distance (P = .03) and increased PVR index (P = .02). In adjusted longitudinal regression in the Children's Hospital of Colorado cohort, ST2 was significantly associated with higher PVR index (P < .001), shorter 6-min walk distance (P = .01), and higher mean pulmonary artery pressure (P < .001). Although the REVEAL Risk Score Calculator 2.0 was predictive of clinical worsening in the PAHB (hazard ratio, 1.88), addition of ST2 significantly improved the model (hazard ratio, 2.05). In cell culture, ST2 was produced and secreted predominately by endothelial cells as opposed to smooth muscle cells (P < .0001).InterpretationIn two pediatric PAH cohorts, elevated ST2 was associated with unfavorable pulmonary hemodynamics and functional measures, clinical worsening, and significantly improved prediction of clinical worsening. Pulmonary artery endothelial cellular expression of ST2 suggests that ST2 is a more pulmonary vascular-specific marker for pulmonary hypertension.

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.

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: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.

Dataset Information

Relationship of soluble ST2 to pulmonary hypertension severity in patients undergoing cardiac resynchronization therapy.

Publications

Relationship of soluble ST2 to pulmonary hypertension severity in patients undergoing cardiac resynchronization therapy.

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