The role of ventricular remodeling in the early decompensation of cardiorenal syndrome: Insight from studies with Ren-2 transgenic hypertensive rats subjected to volume overload induced using aorto-caval fistula

Fig. 1. The experimental design of the whole study, delineating individual experimental series and specific functional evaluation. Series 1 focused on quantification of cardiac function, hemodynamic and organ weight changes A, series 2 focused on histological changes of left ventricular tissue B, series 3 focused on gene expression changes in apex tissue of left ventricle C.

Fig. 2. Organ weight parameters. Whole heart weight A, left ventricle weight B, right ventricle weight C, the ratio of right ventricle weight to left ventricle weight D, left atrium weight E, and lung weight F in sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD), hypertensive sham-operated Ren-2 transgenic (TGR) rats, and in the TGR two weeks after creation of the aorto-caval fistula (ACF). * P < 0.05 compared with sham-operated HanSD rats. @ P < 0.05 compared with all other groups. The values are means ± SEM

Fig. 3. Part 1 of the left ventricular cardiac function assessment by invasive hemodynamic analysis performed in sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD), hypertensive sham-operated Ren-2 transgenic (TGR) rats and in TGR two weeks after creation of the aorto-caval fistula (ACF). The data show left ventricle peak pressure A, left ventricle end-diastolic pressure B, left ventricle end-diastolic volume C, maximum rates of pressure rise ( + dP/dt)max D, maximum rates of pressure fall (-dP/dt)min E and relaxation constant tau of the left ventricle F. * P < 0.05 compared with sham-operated HanSD rats. @ P < 0.05 compared with all other groups. The values are means ± SEM

Fig. 4. Part 2 of the left ventricular cardiac function assessment by invasive hemodynamic analysis performed in sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD), hypertensive sham-operated Ren-2 transgenic (TGR) rats and in TGR two weeks after creation of the aorto-caval fistula (ACF). Shown are: end-systolic pressure-volume relationship (ESPVR) A, end-diastolic pressure-volume relationship (EDPVR) B, preload recruitable stroke work C, stroke work D, arterial elastance E and left ventricle wall stress F. * P < 0.05 compared with sham-operated HanSD rats. @ P < 0.05 compared with all other groups. The values are means ± SEM

Fig. 5. Histological evaluation. Cardiomyocyte width A, cardiomyocyte length B, the ratio of cardiomyocyte length to cardiomyocyte width C, the total fibrosis in the left ventricle D, the amount of mature collagen in the left ventricle E and the amount of newly synthesized collagen in the left ventricle F - in sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD), hypertensive sham-operated Ren-2 transgenic (TGR) rats and in TGR two weeks after creation of the aorto-caval fistula (ACF). * P < 0.05 compared with sham-operated HanSD rats. @ P < 0.05 compared with all other groups. The values are means ± SEM

Fig. 6. Representative histological images of the left ventricle. Sections are stained with Picrosirius Red (200x), in these bright-field microscopy images, the collagen is red against a pale-yellow background. The scale bar in the figure is 100 µm. A sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD) (average fibrosis in this group is 1.57 ± 0.11%), B hypertensive sham-operated Ren-2 transgenic (TGR) rats (average fibrosis in this group is 1.70 ± 0.18%) and C in TGR two weeks after creation of the aorto-caval fistula (ACF) (average fibrosis in this group is 2.83 ± 0.26%)

Fig. 7. The first part of the data for mRNA expression in the left ventricle – gene markers of myocardial stress and contractile function. Natriuretic peptide A A, natriuretic peptide B B, the ratio of the β-myosin heavy chain (Myh7) to α-myosin heavy chain (Myh6) C, sarcoplasmic reticulum Ca2+-ATPase D, phospholamban E and transglutaminase 2 F in sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD), hypertensive sham-operated Ren-2 transgenic (TGR) rats, and in TGR assessed two weeks after creation of the aorto-caval fistula (ACF). * P < 0.05 compared with sham-operated HanSD rats. @ P < 0.05 compared with all other groups. The values are means ± SEM

Fig. 8. The second part of the data for mRNA expression in the left ventricle – gene markers of myocardial metabolism. Glucose transport type 1 A, acyl-CoA dehydrogenase, C-4 to C-12 straight chain B, hexokinase-1 C, and citrate synthase D in sham-operated normotensive transgene-negative Hannover Sprague-Dawley rats (HanSD), hypertensive sham-operated Ren-2 transgenic (TGR) rats, and in TGR two weeks after the creation of the aorto-caval fistula (ACF). * P < 0.05 compared with sham-operated HanSD rats. @ P < 0.05 compared with all other groups. The values are means ± SEM

Fig. 9. Changes in organ weights from the compensation phase [one week after aorto-caval fistula (ACF) creation, data taken from reference #36], via transition phase (two weeks after ACF creation, data taken from the current study) to the decompensation phase (three weeks after ACF creation, data taken from reference #37). Changes are expressed as percent increases in hypertensive Ren-2 transgenic (TGR) rats with ACF compared to sham-operated TGR at the same time. Changes in lung weight A, whole heart weight B, left ventricle weight C, and right ventricle weight D. * P < 0.05 compared with ACF TGR one week after ACF induction. @ P < 0.05 compared with ACF TGR one week as well as two weeks after ACF induction. The values are means ± SEM

Fig. 10. Cardiomyocyte parameters from the compensation phase [one week after aorto-caval fistula (ACF) creation, data taken from reference #36], via transition phase (two weeks after ACF creation, data taken from the current study) to the decompensation phase (three weeks after ACF creation, data from reference #37). Cardiomyocyte width A, cardiomyocyte length B, and the ratio of cardiomyocyte width to length C. * P < 0.05 compared with sham-operated TGR at the same time point. @ P < 0.05: ACF TGR three weeks after ACF creation versus ACF TGR two weeks after ACF induction. # P < 0.05: ACF TGR two weeks after ACF creation versus ACF TGR one week after ACF creation. The values are means ± SEM

Fig. 11. Changes in left cardiac functions (assessed by invasive hemodynamic analysis) from the transition phase (two weeks after ACF creation, data taken from the current study) to the decompensation phase (three weeks after ACF creation, data taken from the reference #37). Changes are expressed as percent increases in hypertensive Ren-2 transgenic (TGR) rats with ACF compared to sham-operated TGR at the same time. Changes are shown in left ventricle peak pressure A, maximum rates of pressure rise ( + dP/dt)max B, end-systolic pressure volume relationship (ESPVR) C, preload recruitable stroke work D, left ventriculo-arterial coupling E and left ventricular efficiency F. * P < 0.05 compared with ACF TGR two weeks after ACF induction