Myocardial Angiotensin-Converting Enzyme 2 Protein Expression in Ischemic Heart Failure

Figures

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  Figure 1. Expression patterns of ACE2 in different groups. (A) Representative images of human myocardium immunohistochemistry for both antibodies (stained with magenta, visible in the cellular membrane and cytoplasm). (B) Pie charts depict group stratification according to the grading scale. (C) The effect of ACEi administration on ACE2 expression. Abbreviations: ACE2, angiotensin-converting enzyme 2; ACEi, angiotensin-converting enzyme inhibitors; HF, heart failure; stages A, B, C, and D HF according to ACC/AHA classification. Scale bar: 100 μm.

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  Figure 2. ACE2 expression in myocardium of different groups. DAB stain digital image analysis (A), data are presented as mean and standard error; nested ANOVAs with Bonferroni post hoc test were applied. Semi-quantitative immunohistochemical analysis of cardiomyocytes (B) and non-cardiomyocytes (C); data are presented as median, the 25th and 75th percentiles, and minimum and maximum values (whiskers); the Kruskal–Wallis test with Bonferroni-adjusted pairwise comparisons was used. * p < 0.001—stage A HF, stage B HF, stages C/D HF vs. control group data; ** p < 0.001—stage B HF and stages C/D HF vs. stage A HF group data; *** p < 0.001—stages C/D HF vs. stage B HF group data; # p < 0.05—stages C/D HF group vs. stage B HF group data. Abbreviations: HF, heart failure; stages A, B, C, and D HF according to ACC/AHA classification.

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  Figure 3. ACE2 protein expression in the human myocardium. Representative images of ACE2 and αSMA co-expression in blood vasculature. Abbreviations: αSMA, alpha smooth muscle actin; ACE2, angiotensin-converting enzyme 2; HF, heart failure; stages A, B, C, and D HF according to ACC/AHA classification. Scale bar: 100 μm.

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  Figure 4. ACE2 protein expression in human myocardium. Representative images of ACE2 and CD31 co-expression in blood vasculature. Abbreviations: ACE2, angiotensin-converting enzyme 2; CD31, cluster of differentiation 31; HF, heart failure; stages A, B, C, and D HF according to ACC/AHA classification. Scale bar: 100 μm.

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  Figure 5. Positive tissue and negative reagent controls for ACE2 which were used for both antibodies and different chromogens ((A) kidney: moderate to strong ACE2 staining was detected in the tubular cells without glomerular expression); for αSMA ((B) liver: the majority of the perisinusoidal cells showed a weak-to-moderate, distinct cytoplasmic staining reaction); for CD31 ((C) liver: all endothelial cells of the sinusoids exhibited a weak-to-moderate predominantly membranous staining reaction). Abbreviations: αSMA, alpha smooth muscle actin; ACE2, angiotensin-converting enzyme 2; CD31, cluster of differentiation 31. Scale bar: 100 μm.