Arginine metabolism and nitric oxide turnover in the ZSF1 animal model for heart failure with preserved ejection fraction

Figures

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  Figure 1. Gene expression of key enzymes involved in arginine metabolism in kidney (A), liver (B) and heart (C) in L-ZSF1 (white squares) and O-ZSF1 (grey squares). Y-axis shows arbitrary units that represent gene expression normalized to Hprt1 and the median of all measurements of the gene. Arg2 and Agxt2 expression in heart was generally low and not detectable in some animals (cycle threshold > 35) irrespective of phenotype and was thus excluded from view. Boxplots visualize the median, 25th and 75th percentiles and minimum/ maximum. P-values were calculated using Kruskal–Wallis test and were corrected for multiple testing using the Bonferroni-Dunn method. *p < 0.05, **p < 0.01.

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  Figure 2. Protein expression of key enzymes involved in arginine metabolism in kidney (A), liver (B) and heart (C) with measurements in right ventricle (RV) and left Ventricle (LV) in L-ZSF1 (white squares) and O-ZSF1 (grey squares). Y-axis shows arbitrary units that represent protein expression normalized to GAPDH (kidney/ heart) or alpha Tubulin (liver). Boxplots visualize the median, 25th and 75th percentiles and minimum/ maximum. P-values were calculated using Kruskal–Wallis test and were corrected for multiple testing using the Bonferroni-Dunn method. #p < 0.1, ***p < 0.001.

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  Figure 3. Arginase 1 concentration (ng/ml) in serum of L-ZSF1 (left side) and O-ZSF1 (right side). Boxplots visualize the median, 25th and 75th percentiles and minimum/ maximum. Two samples of the O-ZSF1 group indicated with red boxes were excluded for p-value calculation that was done using Kruskal–Wallis test.

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  Figure 4. Histological analysis of cardiac macrophage infiltration using CD68 antibody (brown) in sections of O-ZSF1 hearts. Nuclei are stained blue. Exemplary pictures show: (A) and (B) massive accumulation of macrophages, (C) and (D) single cells in different magnifications.

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  Figure 5. Simplified schematic of findings and proposed status of Arg-involving pathways related to NO in heart, circulation, liver and kidney of O-ZSF1 and L-ZSF1 rats. Top—Enzymes (green) with substrates and metabolites (white). Bottom—Analyzed rat organs and tissues with arrows indicating the changes (p < 0.05) compared to L-ZSF1. ↑ higher in O-ZSF1, ↔ no differences, ↓ lower in O-ZSF1. Arrow in brackets indicates a trend (p < 0.1). *Orn/Cit were measured together in Urine. iNOS and Arginase were not determined in cardiac macrophages directly—the depicted regulation is hypothesis generating only.