Characterizing a long-term chronic heart failure model by transcriptomic alterations and monitoring of cardiac remodeling

Figures

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  Figure 1. Monitoring of long-term MI mouse model for 8 months. (A) Limb leads I, II and III of electrocardiogram (ECG) reliably reflect the acute ischemia induced by left coronary ligation in C57BL/6 mice. (B) Lead II ECG can reflect different stages of myocardial infarction (MI) for a time period of 8 months. (C) Triphenyl tetrazolium chloride (TTC)-stained sections of heart in mice with MI for 8 h; the infarct size (IS)/ left ventricle (LV) was approximately 44% in the MI groups. (D) Representative left ventricular aneurysm formed 1 week after MI; (E) Example necropsy images of a dead mouse showing obvious rupture in the left ventricle free wall. (F): Kaplan–Meier survival analysis of mice subjected to MI or sham operation for 8 months. (G) Kaplan–Meier survival analysis of mice subjected to MI or sham operation for 14 days, n = 114 in MI group; Scale bar =2 mm for panel (C, D and E).

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  Figure 2. Pathways enrichment associated with advanced heart failure. (A) WGCNA identified demonstrated 7 modules by average linkage clustering. (B) Gene Ontology analysis of genes in the green module, which were more correlated with advanced heart failure. (C) List of the four significantly up-regulated (marked red) and four down-regulated gene sets (marked green) associated with advanced heart failure enriched in GSEA analysis. (D–E) Enrichment plots of four significantly up-regulated and down-regulated pathways. (F) Heatmap of the enriched genes in the Integrin signaling pathway. (G) Heatmap of the enriched genes in the WNT signaling pathway. (H) Protein-protein interaction network of WNT signaling pathway and hub genes involved in this network.

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  Figure 3. Pathways most affected at 1 month and 8 months after MI. (A) PCA analysis show that the transcriptome of mice after LCA ligation changes significantly and varies with time. (B) Overlap of significantly modulated genes between 1 month and 8 months post-MI. (C) GGO (left) and EGO (right) analysis of pathways affected by long term MI.

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  Figure 4. Serial echocardiographic assessment of post-infarction remodeling. (A) Representative recordings of M-mode echocardiographic images at indicated time points. (B) Left ventricular end-systolic diameter (LVESd). (C) Left ventricular end-diastolic diameter (LVEDd). (D) Left ventricular systolic function presented by the left ventricular ejection fraction (LVEF). (E) Left ventricle fractional shortening (LVFS). *P < 0.05 vs the corresponding time point in the sham group. #P < 0.05 compared with the prior time point in the MI group. n = 8–10 at various time points.

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  Figure 5. Hemodynamics assessment of left ventricular function. (A) Representative recordings of left ventricular (LV) pressure and pressure change rate (dp/dt). (B) LV systolic pressure. (C) LV end-diastolic pressure. (D) Maximum increasing rate of LV pressure (dp/dt max). (E) Maximum descending rate of the LV pressure (dp/dt min). (F) LV contractility index (dp/dt max divided by the pressure at the time of dp/dt max). (G) Exponential time constant of relaxation (Tau). *P < 0.05 compared with the sham group. #P < 0.05 compared with the prior time point in the MI group. n = 6–10 at various time point.

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  Figure 6. Cardiac remodeling validated by morphological and histological analysis. (A) Representative images of whole hearts and cross sections of hearts stained with hematoxylin-eosin staining (HE) and Masson's trichrome staining from different time points (scale bar = 2 mm). (B) Heart weight to body weight ratio (HW/BW). (C) Heart weight to tibia length ratio (HW/TL). (D) Lung weight to body weight ratio (LW/BW). (E) Lung weight to tibia length ratio (LW/TL); n = 8–10 at different time points. (F) Expression of the gene encoding ANP (atrial natrium peptide). (G) Expression of the gene encoding α-MHC (α-myosin heavy chain, Myh6). (H) Expression of β-MHC (Myh7); n = 6 at each time point. *P < 0.05 vs. the corresponding time point in the sham group. #P < 0.05 compared with the prior time point in the MI group.