Intermedin prevents acute heart failure following acute kidney injury by alleviating inflammatory responses

Figure 1.. Expression levels of IMD and its receptors in the kidney and the heart of C57BL/6J mice following AKI. (A) Serum creatinine (Scr) levels; (B) Blood urea nitrogen (BUN) levels; (C) mRNA expression levels of IMD and its receptors in the kidney; (D) mRNA expression levels of IMD and its receptors in the heart; (E) Representative western blot images of IMD and its receptors; (F) Quantitative analysis of protein expression levels of IMD and its receptors in the kidney; (G) Quantitative analysis of protein expression levels of IMD and its receptors in the heart; (H) Immunohistochemical staining of IMD in the kidney; (I) Immunohistochemical staining of IMD in the heart; (J) Semi-quantitative analysis of IMD immunohistochemical staining. The data are presented as the mean ± SD. (n = 6/group). *p < 0.05 and **p < 0.01, IRI versus sham.

Figure 2.. Renal injury in IMD+/+ and IMD−/− mice after kidney ischemia-reperfusion injury. (A) Gross anatomical images of kidneys; (B) Kidney index (mg/g) calculated as bilateral kidney weight/body weight ratio; (C) Serum creatinine (Scr) levels; (D) Blood urea nitrogen (BUN) levels; (E) Paller’ s score based on H&E staining; (F) Representative H&E staining images showing kidney pathological changes (arrows indicate focal necrosis of renal tubular epithelial cells, brush border loss, tubular dilatation with protein casts and cellular debris in lumen, and inflammatory cell infiltration in interstitium); (G) PAS staining results of kidneys. The data are presented as the mean ± SD. (n = 6/group). ns: no significance; *p < 0.05 and **p < 0.01, IRI versus sham; ♯p < 0.05, IMD−/− mice versus IMD+/+ mice at the same time point after IRI.

Figure 3.. Cardiac injury in IMD+/+ and IMD−/− mice after kidney ischemia-reperfusion injury. (A) M-mode echocardiograms of the left ventricle. (B) Left ventricular ejection fraction (LVEF). (C) Left ventricular fractional shortening (LVFS). (D) Left ventricular internal diameter at end-systole (LVIDs) and end-diastole (LVIDd). (E) Left ventricular end-systolic volume (LVESV) and end-diastolic volume (LVEDV). (F) Serum troponin T (Tn-T) levels in mice. (G) Serum brain natriuretic peptide (BNP) levels in mice. (H) Gross anatomical images of the heart. (I) H&E staining of the heart. The data are presented as the mean ± SD. (n = 5-6/group). ns: no significance; *p < 0.05 and **p < 0.01, IRI versus sham; ♯p < 0.05, IMD−/− mice versus IMD+/+ mice at the same time point after IRI.

Figure 4.. Cardiac injury in IMD+/+ and IMD−/− mice after BNX. (A) Serum creatinine (Scr) levels in C57BL/6J mice; (B) Blood urea nitrogen (BUN) levels in C57BL/6J mice; (C) Semi-quantitative analysis of IMD immunohistochemical staining in the heart of C57BL/6J mice; (D) Representative images of IMD immunohistochemical staining in the heart of C57BL/6J mice; (E) Serum Scr levels in mice; (F) Serum BUN levels in mice; (G) Serum troponin T(Tn-T) levels in mice; (H) Serum brain natriuretic peptide (BNP) levels in mice; (I) H&E staining of the heart. The data are presented as the mean ± SD. (n = 5-6/group). ns: no significance; *p < 0.05 and **p < 0.01, BNX versus sham; ♯p < 0.05, IMD−/− mice versus IMD+/+ mice at the same time point after BNX.

Figure 5.. Heart and systemic inflammatory responses in IMD+/+ and IMD−/− mice following AKI. (A) Representative western blot images of inflammation-related proteins in the heart; (B) Quantitative data analysis of TNF-α, IL-6, and IL-1β protein expression levels in the heart; (C) Quantitative data analysis of NF-κB P65 and VCAM-1 protein expression levels in the heart; (D) Serum TNF-α levels in mice; (E) Serum IL-6 levels in mice. The data are presented as the mean ± SD. (n = 5/group). ns: no significance; *p < 0.05 and **p < 0.01, IRI versus sham; ♯p < 0.05, IMD−/− mice versus IMD+/+ mice at the same time point after IRI.