Heart functional and structural compendium of cardiosplenic and cardiorenal networks in acute and chronic heart failure pathology

Abstract

Heart failure (HF) secondary to myocardial infarction (MI) is linked to kidney complications that comprise cellular, structural, functional, and survival indicators. However, HF research is focused on left ventricular (LV) pathology. Here, we determined comprehensive functional analysis of the LV using echocardiography in transition from acute heart failure (AHF) to progressive chronic heart failure (CHF) pathology and developed a histological compendium of the cardiosplenic and cardiorenal networks in pathological remodeling. In surgically induced MI using permanent coronary ligation, the LV dysfunction is pronounced, with myocardium necrosis, wall thinning, and 20-30% LV rupture events that indicated AHF and CHF pathological remodeling in C57BL/6 male mice (2-4 mo old, n = 50). Temporal LV function analysis indicated that fractional shortening and strain are reduced from day 1 to day 5 in AHF and sustained to advance to CHF from day 28 to day 56 compared with naïve control mice ( n = 6). During the transition of AHF ( day 1 to day 5) to advanced CHF ( day 28 to day 56), histological and cellular changes in the spleen were definite, with bimodal inflammatory responses in kidney inflammatory biomarkers. Likewise, there was a unidirectional, progressive, and irreversible deposition of compact collagen in the LV along with dynamic changes in the cardiosplenic and cardiorenal networks post-MI. The renal histology and injury markers suggested that cardiac injury triggers irreversible dysregulation that actively alters the cardiosplenic and cardiorenal networks. In summary, the novel strategies or pathways that modulate comprehensive cardiosplenic and cardiorenal networks in AHF and CHF would be effective approaches to study either cardiac repair or cardiac pathology. NEW & NOTEWORTHY The present compendium shows irreversible ventricular dysfunction as assessed by temporal echocardiography while histological and structural measurements of the spleen and kidney added a novel direction to study cardiosplenic and cardiorenal networks in heart failure pathology. Therefore, the consideration of systems biology and integrative approach is essential to develop novel treatments.

Keywords: fibrosis; ischemia injury; temporal echocardiography.

Fig. 1.

Temporal dynamics of survival and left ventricular (LV) infarcted area in acute heart failure (AHF) and chronic heart failure (CHF) pathology after myocardial infarction (MI). A: LV representative images stained with 2,3,5-triphenyltetrazolium chloride indicated the infarct area (white) in AHF and CHF pathology. B: survival curve of C57BL/6 mice post-MI analyzed using a Kaplan-Meier log-rank test showing 58% survival in heart failure (HF) pathology with no death in naïve control mice. C: pie chart indicating 58% survival (29 of 50 mice), 26% mortality resulting from rupture (13 of 50 mice), and 16% mortality resulting from CHF (8 of 50 mice). n = 56 mice total for AHF and CHF temporal dynamic measurements.

Fig. 2.

Time-dependent structural changes in the infarct, peri-infarct (border zone or area at risk), and remote (noninfarcted) areas in acute heart failure (AHF) and chronic heart failure (CHF) pathology. A−C: hematoxylin and eosin (H&E) staining of ×1.25 images of the complete left ventricle (LV; A), ×40 images of the remote zone (B), and ×40 images of the peri-infarct zone and quantitative analyses as a bar graph (C). D: ×40 images of the infarct zone in C57BL/6 mice during AHF and CHF displaying changes in ultrastructure and quantitative analyses as a bar graph. n = 7–8 mice/group. Scale bar = 50 μm.

Fig. 3.

Temporal long-axis B-mode longitudinal strain (two- and three-dimensional) and segmental strain indicated the progressive dynamic changes in left ventricular (LV) size, shape, and function in acute heart failure (AHF) and chronic heart failure (CHF) after myocardial infarction (MI). A: echocardiographic representation of speckle-tracking analysis in the long-axis B-mode; the LV is in midsystole. B and C: longitudinal three-dimensional strain (B) and longitudinal segmental synchronicity (C) of the LV. Images are representatives of n = 7–8 mice/group.

Fig. 4.

Consecutive short-axis B-mode, left ventricular (LV) wall trace M-mode, and segmental strain indicated the irreversible cardiac remodeling in acute heart failure (AHF) and chronic heart failure (CHF) pathology after myocardial infarction (MI). A: echocardiographic representation of speckle-tracking analysis in short-axis B-mode equipped with M-mode wall trace. B: representative short-axis M-mode LV wall trace. C: representative echocardiographic traces of short-axis circumferential segmental synchronicity. D: circumferential three-dimensional strain. LV images are representative of n = 7–8 mice/group.

Fig. 5.

Picrosirius red (PSR)-stained left ventricular (LV) fibrotic remodeling and temporal changes of collagen in remote, peri-infarct, and infarct area in acute heart failure (AHF) and chronic heart failure (CHF) pathology. Representative images of PSR staining depicting fibrosis. A: ×1.25 images of the complete LV. B: ×40 images of the remote zone. C: ×40 images of the peri-infarct zone and quantitative analyses as a bar graph. D: ×40 images of the infarct zone in C57BL/6 mice during AHF and CHF displaying temporal changes in fibrosis during heart failure progression and quantitative analyses as a bar graph (scale bar = 50 µm). n = 7–8 mice/group. *P < 0.05 vs. no-MI control.

Fig. 6.

Sequential changes in splenic remodeling in acute heart failure (AHF) and chronic heart failure (CHF) after myocardial infarction (MI), particularly in the germinal center, marginal zones (MZs), and red pulp (RP) and white pulp (WP). A and B: hematoxylin and eosin-stained images of the spleen from C57BL/6 mice during AHF and CHF displaying temporal changes in the WP area, RP area, and MZ. C: immunofluorescence images representing kinetics of F4/80⁺ macrophages (green) and Foxp3⁺ (red) in the spleen in AHF and CHF. Scale bar = 50 µm. Magnification: ×20. n = 7–8 mice/group for hematoxylin and eosin staining and n = 2 for immunofluorescence.

Fig. 7.

Periodic acid-Schiff (PAS)-stained renal structural remodeling in acute heart failure (AHF) and chronic heart failure (CHF) pathology with the marked bimodal response of inflammatory markers in the kidney. A: PAS staining indicating granulomatous kidney inflammation in progressive ACF and CHF. B: immunofluorescence images showing immediate increase in neutrophil gelatinase-associated lipocalin (NGAL) expression (red) and nuclei (blue) at day 1 after myocardial infarction (MI) (AHF) followed by the bimodal response at day 28 post-MI (CHF) in the kidney glomerulus and tubular area. C: decrease in nephrin expression (red) in the glomerulus diffused by cardiorenal inflammation during AHF and CHF. Nuclei are stained blue. D: plasma creatinine level in AHF and CHF. E: plasma NGAL levels in AHF and CHF. F: mRNA levels of NGAL in AHF and CHF. Values are means ± SE; n = 6–8 mice/group. Magnification is 3.84 zoom of ×40 for images. Scale bar = 50 µm. n = 7–8 mice/group for PAS staining and n = 2 for immunofluorescence. *P < 0.05 vs. no-MI control.