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 expression of NGAL/lcn2 (neutrophil gelatinase-associated lipocalin) is directly modulated by mineralocorticoid receptor activation but its role in blood pressure control is unclear. METHODS: a potential relationship between NGAL plasma levels, systolic blood pressure and urinary Na excretion was assessed in the STANISLAS cohort. The specific role of NGAL/lcn2 in salt-sensitive hypertension was studied using lcn2-knockout mice (lcn2 KO) fed with low-Na diet (0Na). RESULTS: we show that NGAL plasma levels positively correlate with systolic blood pressure, whereas they negatively correlate with urinary Na excretion in subjects of the STANISLAS cohort. Prolonged feeding of lcn2 KO mice with a 0Na diet induced lower systolic blood pressure than that of the control group (wildtype), suggesting a role for NGAL/lcn2 in Na-balance homeostasis. Short-term or prolonged 0Na increased Na-Cl cotransporter (NCC) phosphorylation in the cortex of wildtype mice, which was prevented in lcn2 KO mice. Recombinant mouse lcn2 injections in lcn2 KO mice induced NCC phosphorylation in the kidney cortex, associated with decreased urinary Na excretion. Ex vivo experiments using kidney slices from lcn2 KO mice showed increased NCC phosphorylation by recombinant murine lcn2. In addition, recombinant murine lcn2 induced activation of CamK2β (calcium/calmodulin-dependent protein kinase II β subunit) phosphorylation in lcn2 KO mice and in kidney slices, providing an underlying mechanism involved in lcn2-induced NCC phosphorylation. Indeed, the inhibition of CamK2β prevented NCC phosphorylation induced by recombinant lcn2 in kidney slices. CONCLUSIONS: we highlight a novel role of NGAL/lcn2 as a modulator of the activity of the renal sodium transporter NCC affecting salt-sensitive blood pressure

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.

Myocardial infarction is the most common cause of death worldwide. An understanding of the alterations in protein pathways is needed in order to develop strategies that minimize myocardial damage. To identify the protein signature of cardiac ischemia/reperfusion (I/R) injury in rats, we combined, for the first time, protein matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) and label-free proteomics on the same tissue section placed on a conductive slide. Wistar rats were subjected to I/R surgery and sacrificed after 24 h. Protein MALDI-MSI data revealed ischemia specific regions, and distinct profiles for the infarct core and border. Firstly, the infarct core, compared to histologically unaffected tissue, showed a significant downregulation of cardiac biomarkers, while an upregulation was seen for coagulation and immune response proteins. Interestingly, within the infarct tissue, alterations in the cytoskeleton reorganization and inflammation were found. This work demonstrates that a single tissue section can be used for protein-based spatial-omics, combining MALDI-MSI and label-free proteomics. Our workflow offers a new methodology to investigate the mechanisms of cardiac I/R injury at the protein level for new strategies to minimize damage after MI.

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: Aortic stenosis is the most common valvular heart disease, and its progression is accelerated in chronic kidney disease (CKD), where multiple circulating abnormalities worsen its pathophysiology. This study examined the impact of CKD‐related aldosterone excess, focusing on mineralocorticoid receptor signaling and its crosstalk with the innate immune pathway mediated by Toll‐like receptor 4 (TLR4) in aortic valve (AV) interstitial cells and AV tissue. Methods: For the study, we conducted in vivo studies using a CKD rat model challenged with high phosphate, followed by ex vivo analysis of AVs. In parallel, primary rat and human valve interstitial cells were used in vitro to evaluate inflammatory, fibrotic, and osteogenic responses to aldosterone and to identify the key signaling pathways involved. Human AVs from patients with aortic stenosis were also analyzed. Quantitative polymerase chain reaction, western blot, and ELISA were used to characterize these pathways. Results: Mineralocorticoid receptor activation emerged as a central driver of aortic stenosis progression in CKD, promoting valve interstitial cell differentiation, inflammation, fibrosis, and calcification through activation of the TLR4–myeloid differentiation primary response 88 innate immunity pathway in response to aldosterone. Moreover, chemerin was identified as a downstream effector of the mineralocorticoid receptor that activates TLR4, further enhancing remodeling and calcification in AVs and valve interstitial cells. These results were corroborated in human stenotic AV samples from patients with CKD. Conclusions: Collectively, the study defines a novel mineralocorticoid receptor–TLR4–chemerin axis that mediates aldosterone‐driven inflammatory and calcific processes in CKD, in both a rat model and in vitro systems.