Neuregulin-1β Improves Uremic Cardiomyopathy and Renal Dysfunction in Rats

Abstract

Chronic kidney disease is a global health problem affecting 10% to 12% of the population. Uremic cardiomyopathy is often characterized by left ventricular hypertrophy, fibrosis, and diastolic dysfunction. Dysregulation of neuregulin-1β signaling in the heart is a known contributor to heart failure. The systemically administered recombinant human neuregulin-1β for 10 days in our 5/6 nephrectomy-induced model of chronic kidney disease alleviated the progression of uremic cardiomyopathy and kidney dysfunction in type 4 cardiorenal syndrome. The currently presented positive preclinical data warrant clinical studies to confirm the beneficial effects of recombinant human neuregulin-1β in patients with chronic kidney disease.

Keywords: cardiac fibrosis; chronic kidney disease; left ventricular hypertrophy; recombinant human neuregulin-1β; uremic cardiomyopathy.

Graphical abstract

Figure 1

The Effects of rhNRG-1β on the Development of CKD at Week 10 (A) NRG-1β protein expression in left ventricles and (B) kidney tissue at week 10 in 5/6 nephrectomized rats (unpaired Student t test). (C) Serum carbamide concentration, (D) serum creatinine concentration, (E) urine protein concentration, (F) creatinine clearance, (G) plasma p-cresyl sulfate concentration, and (H) plasma indoxyl sulfate concentration at week 10. Values are presented as mean ± SEM. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, n = 7-10, 1-way analysis of variance, Holm-Sidak post hoc test. CKD = chronic kidney disease group; CKD + rhNRG-1β = recombinant human neuregulin-1β-treated chronic kidney disease group; LV = left ventricular; Sham = sham-operated group.

Figure 2

The Effects of rhNRG-1β on Echocardiographic Parameters at Weeks 4 and 10 (A) Representative M-mode and (B) tissue Doppler images, (C) posterior wall thickness in systole (PWTs), and (D) diastole (PWTd), (D) left ventricular ejection fraction (EF), (E) ratio of early mitral flow velocity (E) and diastolic septal mitral annulus velocity (E') at week 4, (F) posterior wall thickness in systole (PWTs) and (G) diastole (PWTd) at week 10, (H) left ventricular EF, and (I) E/E' at week 10. Values are presented as mean ± SEM. ∗ P < 0.05, ∗∗P < 0.01, n = 7-10, 1-way analysis of variance, Holm-Sidak post hoc test. Abbreviations as in Figure 1.

Figure 3

The Effects of rhNRG-1β on LV and Renal Morphology Assessed by Histology at Week 10 (A) Representative hematoxylin-eosin (HE)-stained slides and picrosirius red/fast green (PSFG)-stained slides of left ventricles. (B) cardiomyocyte cross-sectional areas, (C) perimeters, (D) left ventricular (LV) fibrosis, (E) representative HE-stained slides and PSFG-stained slides of the kidney tissue, (F) glomerular capillary area, (G) tubular lumen area, and (H) kidney interstitial fibrosis. In the case of left ventricles, scale bars represent 50 μm in the HE images and 100 μm in the PSFG images. In the case of kidney tissue, scale bars represent 100 μm in the HE images and 200 μm in the PSFG images. Values are presented as mean ± SEM, ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, n = 7-10, one-way analysis of variance, Holm-Sidak post hoc test. Abbreviations as in Figure 1.

Figure 4

The Effects of rhNRG-1β on mRNA Expressions in Uremic Cardiomyopathy in Left Ventricular Samples mRNA expressions of (A)Col 1, collagen 1; (B)Col 3, collagen 3; (C) alpha-smooth muscle actin (Acta2), alpha-smooth muscle actin; (D)Mmp2, matrix metalloprotease 2; (E) Mmp9, matrix metalloprotease 9; (F)Nppb, B-type natriuretic peptide; (G)Ace1, angiotensin-converting enzyme; (H)Agtr1, angiotensin II type 1 receptor; and (I)Il6, interleukin 6 in left ventricles. Data are expressed as mean ± SEM; n = 8/group, ∗∗P < 0.01, ∗∗∗P < 0.001, 1-way analysis of variance, Tukey post hoc test. Abbreviations as in Figure 1.

Figure 5

The Effects of rhNRG-1β on mRNA Expressions in Human Ventricular Cardiac Fibroblasts (A) Representative 4,6-diamidino-2-phenylindole (DAPI) and αSMA staining of human ventricular cardiac fibroblasts. The mRNA expression of (B)α SMA, alpha-smooth muscle actin; (C)Col 1, collagen 1; (D)Col 3, collagen 3; and LOX1, lysyl oxidase 1 in human ventricular cardiac fibroblasts. Scale bar, 50 μm. Data are expressed as mean ± SEM, n = 6 replicates/group; ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.01, one-way analysis of variance, Tukey post hoc test. Ctrl = control; TGF-β = transforming growth factor beta; ErbB3 AB = EbB3 antibody; other abbreviations as in Figure 1.

Figure 6

The Effect of rhNRG-1β on the Isolated Murine Cardiomyocytes Treated by ANG II (A)Nppa, A-type natriuretic peptide, (B)Nppb, B-type natriuretic peptide, (C)Tnf, tumor necrosis factor-alpha, (D)Nox2, NADPH oxidase isoform 2, (E)Nox4, NADPH oxidase isoform 4, and (F) 3-NT, 3-nitrotyrosine. Data are expressed as mean ± SEM, n = 10 replicates/group; ∗P < 0.05, ∗∗P < 0.01 and ∗∗∗P < 0.01, 1-way analysis of variance, Tukey post hoc test. ANG II + angiotensin II. Abbreviations as in Figure 1.