NGAL (neutrophil gelatinase-associated lipocalin; or lipocalin 2, Lcn2) is a novel mineralocorticoid target in the cardiovascular system. We showed that Lcn2 gene invalidation protects against proteinuria and renal injury upon mineralocorticoid excess and we hypothesized that NGAL produced from macrophages promotes the expression of chemoattractant molecules involved these renal lesions. The role of NGAL was analyzed using myeloid-specific (MΦ KO NGAL) Lcn2 knockout mice challenged with uni-nephrectomy, aldosterone, and salt (NAS) for 6 weeks. The role of the CCL5 (chemokine ligand 5) and IL4 (interleukin 4) in kidney fibrosis was studied by administration of the CCL5 receptor antagonist maraviroc or by injections of an anti-IL4 neutralizing antibody. In CTL mice, NAS increased the renal expression of extracellular matrix proteins, such as collagen I, αSMA, and fibronectin associated with interstitial fibrosis which were blunted in MΦ KO NGAL mice. The expression of CCL5 was blunted in sorted macrophages from MΦ KO NGAL mice challenged by NAS and in macrophages obtained from KO NGAL mice and challenged ex vivo with aldosterone and salt. The pharmacological blockade of the CCL5 receptor reduced renal fibrosis and the CD4 ⁺ Th cell infiltration induced by NAS. Neutralization of IL4 in NAS mice blunted kidney fibrosis and the overexpression of profibrotic proteins, such as collagen I, αSMA, and fibronectin. In conclusion, NGAL produced by macrophages plays a critical role in renal fibrosis and modulates the CCL5/IL4 pathway in mice exposed to mineralocorticoid excess.

The mineralocorticoid receptor (MR) plays an important role in the development of chronic kidney disease (CKD) and associated cardiovascular complications. Antagonizing the overactivation of the MR with MR antagonists (MRA) is a therapeutic option, but their use in patients with CKD is limited due to the associated risk of hyperkalemia. Finerenone is a non-steroidal MRA associated with an improved benefit-risk profile in comparison to steroidal MRAs. In this study, we decided to test whether finerenone improves renal and cardiac function in male hypertensive and diabetic ZSF1 rats as an established preclinical HFpEF model. Finerenone was administered at 10 mg/kg/day for 12 weeks. Cardiac function/hemodynamics were assessed in vivo. ZSF1 rats showed classical signs of CKD with increased BUN, UACR, hypertrophy, and fibrosis of the kidney together with characteristic signs of HFpEF including cardiac fibrosis, diastolic dysfunction, and decreased cardiac perfusion. Finerenone treatment did not impact kidney function but reduced renal hypertrophy and cardiac fibrosis. Interestingly, finerenone ameliorated diastolic dysfunction and cardiac perfusion in ZSF1 rats. In summary, we show for the first time that non-steroidal MR antagonism by finerenone attenuates cardiac diastolic dysfunction and improves cardiac perfusion in a preclinical HFpEF model. These cardiac benefits were found to be largely independent of renal benefits.

Background: The mineralocorticoid receptor plays a significant role in the development of chronic kidney disease (CKD) and associated cardiovascular complications. Classic steroidal mineralocorticoid receptor antagonists are a therapeutic option, but their use in the clinic is limited due to the associated risk of hyperkalemia in patients with CKD. Finerenone is a nonsteroidal mineralocorticoid receptor antagonist that has been recently investigated in 2 large phase III clinical trials (FIDELIO‐DKD [Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease] and FIGARO‐DKD [Finerenone in Reducing Cardiovascular Mortality and Morbidity in Diabetic Kidney Disease]), showing reductions in kidney and cardiovascular outcomes. Methods and Results: We tested whether finerenone improves renal and cardiac function in a preclinical nondiabetic CKD model. Twelve weeks after 5/6 nephrectomy, the rats showed classic signs of CKD characterized by a reduced glomerular filtration rate and increased kidney weight, associated with left ventricular (LV) diastolic dysfunction and decreased LV perfusion. These changes were associated with increased cardiac fibrosis and reduced endothelial nitric oxide synthase activating phosphorylation (ser 1177). Treatment with finerenone prevented LV diastolic dysfunction and increased LV tissue perfusion associated with a reduction in cardiac fibrosis and increased endothelial nitric oxide synthase phosphorylation. Curative treatment with finerenone improves nondiabetic CKD‐related LV diastolic function associated with a reduction in cardiac fibrosis and increased cardiac phosphorylated endothelial nitric oxide synthase independently from changes in kidney function. Short‐term finerenone treatment decreased LV end‐diastolic pressure volume relationship and increased phosphorylated endothelial nitric oxide synthase and nitric oxide synthase activity. Conclusions: We showed that the nonsteroidal mineralocorticoid receptor antagonist finerenone reduces renal hypertrophy and albuminuria, attenuates cardiac diastolic dysfunction and cardiac fibrosis, and improves cardiac perfusion in a preclinical nondiabetic CKD model.

BACKGROUND: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular complications. We have shown that Ngal (neutrophil gelatinase–associated lipocalin)/lcn2 is involved in aldosterone-induced cardiac remodeling and inflammation. Here, we investigated the role of Ngal in the progression of cardiorenal syndrome. METHODS: CKD was induced in rats via 5/6 nephrectomy in wild-type and Ngal knockout rats. Cardiorenal functions were assessed 3 months after subtotal nephrectomy or sham operation. Cardiac fibroblasts were isolated from wild-type rats and incubated with or without rNgal (recombinant Ngal) and Gal-3 (galectin-3). RESULTS: Cardiac perfusion was less impaired in CKD Ngal knockout than in CKD wild type. Left ventricle interstitial fibrosis was more severe in CKD wild type than in sham but was blunted in CKD Ngal knockout rats. Levels of Gal-3, Col1 (collagen 1), Ccl2 (C-C motif chemokine ligand 2), and IL-6 (interleukin-6) were high in cardiac fibroblasts incubated with rNgal. A similar pattern was observed in cells treated with recombinant Gal-3. Both Ngal and Gal-3 induced activation of the Tlr4 (toll-like receptor 4)-Myd88 (myeloid differentiation primary response 88) pathway. The effects of rNgal were blunted by concomitant treatment with Gal-3 or Tlr4 inhibitors, suggesting that Gal-3 contributes to Ngal-induced cardiac fibrosis and inflammation by activating the Tlr4-Myd88 pathway. In both MEDIA-DHF (Metabolic Road to Diastolic Heart Failure) and BIOSTAT-CHF (Biology Study to Tailored Treatment in Chronic Heart Failure) cohorts, elevated levels of Ngal and Gal-3 were associated with advanced diastolic dysfunction and adverse clinical outcomes, particularly among patients with impaired renal function. CONCLUSIONS: In CKD rats, Ngal was involved in cardiac remodeling via a Gal-3/Tlr4-dependent pathway, increasing inflammation and fibrosis, and correlated to cardiac outcomes in the MEDIA-DHF and BIOSTAT-CHF cohorts.

Background: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular (CV) complications. Neutrophil gelatinase-associated lipocalin (NGAL) is a well established marker of kidney injury, but recent evidence suggests that NGAL might also play an active in the progression of the cardiorenal syndrome. Methods: CKD was induced in rats via 5/6 nephrectomy in wild-type (WT) and Ngal-knockout (KO) rats. Cardiorenal functions were assessed three months after subtotal nephrectomy or sham operation. Cardiac fibroblasts (CFs) were incubated with or without recombinant Ngal and galectin-3 (Gal-3). Results: Cardiac function, including diastolic hemodynamics and perfusion, was less impaired in CKD Ngal KO than in CKD WT. Cardiac fibrosis was more severe in CKD WT than sham, but was blunted in CKD Ngal KO rats. Levels of Gal-3, collagen I, MCP-1 and IL-6 were elevated in cardiac fibroblasts incubated with recombinant Ngal. A similar pattern was observed in cells treated with recombinant Gal-3. Both Ngal and Gal-3 induced activation of the Tlr4-Myd88 pathway. Using Gal-3 or Tlr4 inhibitors, we showed that Gal-3 contributes to Ngal-induced cardiac fibrosis and inflammation by activating the Tlr4-Myd88 pathway. In patients with heart failure with preserved ejection fraction (HFpEF) (MEDIA-DHF and BIOSTAT-CHF cohorts), elevated levels of NGAL and Gal-3 were associated with pulmonary artery systolic pressure, a marker of advanced diastolic dysfunction and adverse clinical outcomes, particularly among patients with impaired renal function. Conclusion: In non-diabetic CKD rats, Ngal was involved in the progression of diastolic dysfunction via a Gal-3/Tlr4-dependent pathway increasing inflammation and fibrosis.