The incidence and implications of aldosterone breakthrough

Tetrandrine inhibits aldosterone synthesis by covalently targeting CYP11A1 to attenuate hypertension

Introduction

Tetrandrine (Tet) is the main pharmacological component of Stephania tetrandra S. Moore, which is a well-documented traditional Chinese medicine known for its diuretic and antihypertensive properties. Unraveling the specific targets and mechanisms of Tet involved in inducing diuresis and mitigating hypertension can provide valuable insights into its therapeutic effects. This study aimed to explore the diuretic and antihypertensive targets and mechanisms of Tet using chemical biology coupled with activity analyses in vivo and in vitro.

Methods

The diuretic effects of Tet were evaluated using a water-loaded mouse model. The direct target proteins for the diuretic and antihypertensive effects of Tet were determined using chemical biology. Furthermore, the molecular mechanism of Tet binding to target proteins was analyzed using a multidisciplinary approach based on the structure and function of the proteins. Finally, the effects of the Tet-targeted protein on downstream signaling pathways and blood pressure were evaluated in hypertensive model rats.

Results

Tet exhibited significant antihypertensive and potassium-preserving diuretic effects. The mechanism underlying these effects involves the modulation of the enzyme activity by covalent binding of Tet to Cys423 of CYP11A1. This interaction alters the stability of heme within CYP11A1, subsequently impeding electron transfer and inhibiting aldosterone biosynthesis.

Discussion

This study not only revealed the mechanism of the diuretic and antihypertensive effects of Tet but also discovered a novel covalent inhibitor of CYP11A1. These findings contribute significantly to our understanding of the therapeutic potential of Tet and provide a foundation for future research in the development of targeted treatments for hypertension.

Renal effects and safety between Asian and non-Asian chronic kidney disease and type 2 diabetes treated with nonsteroidal mineralocorticoid antagonists

BACKGROUND

Asians bear a heavier burden of chronic kidney disease (CKD), a common comorbidity of type 2 diabetes mellitus (T2DM), than non-Asians. Nonsteroidal mineralocorticoid receptor antagonists (MRAs) have garnered attention for their potential advantages in renal outcomes. Nevertheless, the impact on diverse ethnic groups remains unknown.

METHODS

The PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang database, and clinical trial registries were searched through August 2023 with the following keywords: nonsteroidal MRAs (finerenone, apararenone, esaxerenone, AZD9977, KBP-5074), CKD, T2DM, and randomized controlled trial (RCT). A random effects model was used to calculate overall effect sizes.

RESULTS

Seven RCTs with 14 997 participants were enrolled. Nonsteroidal MRAs reduced urinary albumin to creatinine ratio (UACR) significantly more in Asians than non-Asians: (weighted mean difference [WMD], -0.59, 95% CI, -0.73 to -0.45, p < .01) vs (WMD, -0.29, 95% CI, -0.32 to -0.27, p < .01), respectively. The average decline of estimated glomerular filtration rate (eGFR) was similar in Asians and non-Asians (p > .05). Regarding systolic blood pressure (SBP), nonsteroidal MRAs had a better antihypertension performance in Asians (WMD, -5.12, 95% CI, -5.84 to -4.41, p < .01) compared to non-Asians (WMD, -3.64, 95% CI, -4.38 to -2.89, p < .01). A higher incidence of hyperkalemia and eGFR decrease ≥30% was found in Asians than non-Asians (p < .01).

CONCLUSIONS

Nonsteroidal MRAs exhibited significant renal benefits by decreasing UACR and lowering SBP in Asian than that of non-Asian patients with CKD and T2DM, without increase of adverse events except hyperkalemia and eGFR decrease ≥30%.

Insights into drug development with quantitative systems pharmacology: A prospective case study of uncovering hyperkalemia risk in diabetic nephropathy with virtual clinical trials

The quantitative systems pharmacology (QSP) approach is widely applied to address various essential questions in drug discovery and development, such as identification of the mechanism of action of a therapeutic agent, patient stratification, and the mechanistic understanding of the progression of disease. In this review article, we show the current landscape of the application of QSP modeling using a survey of QSP publications over 10 years from 2013 to 2022. We also present a use case for the risk assessment of hyperkalemia in patients with diabetic nephropathy treated with mineralocorticoid receptor antagonists (MRAs, renin-angiotensin-aldosterone system inhibitors), as a prospective simulation of late clinical development. A QSP model for generating virtual patients with diabetic nephropathy was used to quantitatively assess that the nonsteroidal MRAs, finerenone and apararenone, have a lower risk of hyperkalemia than the steroidal MRA, eplerenone. Prospective simulation studies using a QSP model are useful to prioritize pharmaceutical candidates in clinical development and validate mechanism-based pharmacological concepts related to the risk-benefit, before conducting large-scale clinical trials.

Comprehensive characterization of the effect of mineralocorticoid receptor antagonism with spironolactone on the renin-angiotensin-aldosterone system in healthy dogs

OBJECTIVE

To characterize the dose-exposure-response effect of spironolactone on biomarkers of the classical and alternative arms of the renin-angiotensin-aldosterone system (RAAS) in healthy dogs.

ANIMALS

Ten healthy purpose-bred Beagle dogs.

PROCEDURES

Study dogs were randomly allocated to 2 spironolactone dosing groups (2 mg/kg PO q24hr, 4 mg/kg PO q24hr). The dogs received 7-day courses of spironolactone followed by a 14-day washout period in a crossover (AB/BA) design. Angiotensin peptides and aldosterone were measured in serum using equilibrium analysis, and plasma canrenone and 7-α-thiomethyl spironolactone (TMS) were quantified via liquid chromatography-mass spectrometry/mass spectroscopy (LC-MS/MS). Study results were compared before and after dosing and between groups.

RESULTS

Following spironolactone treatment, dogs had a significant increase in serum aldosterone concentration (P = 0.07), with no statistical differences between dosing groups. Significant increases in angiotensin II (P = 0.09), angiotensin I (P = 0.08), angiotensin 1-5 (P = 0.08), and a surrogate marker for plasma renin activity (P = 0.06) were detected compared to baseline following spironolactone treatment during the second treatment period only. Overall, changes from baseline did not significantly differ between spironolactone dosages. RAAS analytes were weakly correlated (R < 0.4) with spironolactone dosage and plasma canrenone or plasma TMS. There were no adverse clinical or biochemical effects seen at any spironolactone dosage during treatment.

CONCLUSIONS

Treatment with spironolactone increased serum aldosterone concentration in healthy dogs and impacted other biomarkers of the classical and alternative arms of the RAAS. There was no difference in effect on the RAAS between 2 and 4 mg/kg/day dosing. Dosage of 4 mg/kg/day was safe and well-tolerated in healthy dogs.

Gene expression analysis to identify mechanisms underlying improvement of myocardial fibrosis by finerenone in SHR

Both spironolactone and finerenone treatments significantly reduced SBP and there was no statistical difference in their antihypertensive effects. The differences in body weight (at the end of 1/2/3/4 week) to pre-dose body weight ratio and heart rate (at the end of 1/2/3/4 week) to pre-dose heart rate ratio were not statistically significant in the vehicle, spironolactone, finerenone, and control groups.There was no statistically significant difference in mortality among the vehicle, spironolactone, and finerenone groups. The relative heart mass, ANP, BNP, CVF, Col I, TGF-β, and Casp-3 were gradually decreased in vehicle group, spironolactone group, and finerenone group. Among them, BNP, CVF, TGF-β, and Casp-3 were significantly decreased in the finerenone group compared with the vehicle group. HE and Masson staining showed that the cardiomyocytes of rats in the vehicle group and spironolactone group were disorganized, with cell hypertrophy, significantly enlarged cell gaps and a large amount of collagen deposition, whereas the cardiomyocytes of rats in the finerenone group and the control group were more neatly arranged, with smaller cell gaps and a small amount of collagen tissue deposition. RNA sequencing (RNA-seq) showed that there was a total of 119 differentially expressed genes (DEGs) between finerenone treatment and vehicle treatment. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the signaling pathways involved were mainly in drug metabolism-cytochrome P450, chemical carcinogenesis, IL-17 signaling pathway, axon guidance, and hematopoietic cell lineage. Protein-protein interaction (PPI) analysis showed that the core genes were Oaslf, Nos2, LOC687780, Rhobtb1, Ephb3, and Rps27a.

Mineralocorticoid receptor overactivation: targeting systemic impact with non-steroidal mineralocorticoid receptor antagonists

The overactivation of the mineralocorticoid receptor (MR) promotes pathophysiological processes related to multiple physiological systems, including the heart, vasculature, adipose tissue and kidneys. The inhibition of the MR with classical MR antagonists (MRA) has successfully improved outcomes most evidently in heart failure. However, real and perceived risk of side effects and limited tolerability associated with classical MRA have represented barriers to implementing MRA in settings where they have been already proven efficacious (heart failure with reduced ejection fraction) and studying their potential role in settings where they might be beneficial but where risk of safety events is perceived to be higher (renal disease). Novel non-steroidal MRA have distinct properties that might translate into favourable clinical effects and better safety profiles as compared with MRA currently used in clinical practice. Randomised trials have shown benefits of non-steroidal MRA in a range of clinical contexts, including diabetic kidney disease, hypertension and heart failure. This review provides an overview of the literature on the systemic impact of MR overactivation across organ systems. Moreover, we summarise the evidence from preclinical studies and clinical trials that have set the stage for a potential new paradigm of MR antagonism.

A Prospective Study of Eplerenone in the Treatment of Patients with Glomerulonephritis

BACKGROUND

High aldosterone levels contribute to kidney disease progression, while spironolactone in combination with ACEi or ARBs can potentially reduce proteinuria and ameliorate kidney function deterioration. However, evidence on the impact of eplerenone in patients with glomerulonephritis is scarce.

METHODS

In this prospective observational study, we assessed the effects of eplerenone in patients with biopsy-proven glomerulonephritis who were already treated with ACEi or ARBs. Patients received either eplerenone (25 mg daily) on top of ACEi or ARBs or standard treatment alone. Proteinuria (24 h total protein excretion), kidney function, blood pressure and serum K+ levels were assessed at 3, 6 and 12 months after the initiation of treatment.

RESULTS

Sixty-six patients were included in the study. Eplerenone was administered in 30 patients, while 36 received only ACEi or ARB. Proteinuria decreased from 1768 to 1152 mg/24 h after 1 year of eplerenone treatment, while it remained stable in controls. Eplerenone showed significant impact on proteinuria in those with baseline proteinuria of >1000 mg/24 h. Patients who received eplerenone showed a reduction in systolic blood pressure, while eGFR and serum K+ levels remained stable.

CONCLUSIONS

Addition of eplerenone has a beneficial effect on proteinuria in patients with glomerulonephritis and significant baseline proteinuria.

[The role of mineralocorticoid receptors hyperactivation in the development of cardiorenal complications in patients with diabetes mellitus, perspective of the selective nonsteroidal mineralocorticoid receptors antagonist's treatment: A review]

The renin-angiotensin-aldosterone system (RAAS) activation plays a key role in the chronic kidney disease (CKD) progression and in the cardiovascular complications (CVC) development in patients with diabetes mellitus (DM). RAAS blockers alone are not sufficient to prevent CVC and CVC progression. RAAS upregulation in CKD associated with DM triggers the mineralocorticoid receptors (MCR) hyperactivation which results in fibrosis and inflammation in the heart and kidneys. This review presents the current data about the variety of MCR hyperactivation manifestations, as well as about of multiplicity of MCR hyperactivation ways in DM. The efficacy and safety of finerenone, a new MCR nonsteroidal selective antagonist, are discussed.

Response and survival of dogs with proteinuria (UPC > 2.0) treated with angiotensin converting enzyme inhibitors

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEi) are a recommended treatment for glomerular proteinuria. Frequency of response to ACEi and the association of achieving proposed urine protein-to-creatinine ratio (UPC) targets on survival is unknown.

OBJECTIVES

To determine response rates to ACEi therapy and whether a positive response is associated with improved survival.

ANIMALS

Eighty-five dogs with proteinuria (UPC > 2.0).

METHODS

Retrospective study including dogs (UPC > 2.0) prescribed an ACEi for treatment of proteinuria. Baseline creatinine, albumin, cholesterol, UPC, and systolic blood pressure were recorded, and cases reviewed to track UPC. Treatment response was defined as achieving a UPC of <0.5 or reduction of ≥50% from baseline within 3 months. Outcome data were collected to determine overall and 12-month survival.

RESULTS

Thirty-five (41%) dogs responded to ACEi treatment. Treatment response was statistically associated with both median survival time (664 days [95% confidence interval (CI): 459-869] for responders compared to 177 [95% CI: 131-223] for non-responders) and 12-month survival (79% responders alive compared to 28% non-responders). Baseline azotemia or hypoalbuminemia were also associated with a worse prognosis, with odds ratios of death at 12 months of 5.34 (CI: 1.85-17.32) and 4.51 (CI: 1.66-13.14), respectively. In the 25 dogs with normal baseline creatinine and albumin, response to treatment was associated with 12-month survival (92% responders alive compared to 54% non-responders, P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

When the UPC is >2.0, achieving recommended UPC targets within 3 months appears to be associated with a significant survival benefit. Response to treatment is still associated with survival benefit in dogs with less severe disease (no azotemia or hypoalbuminemia).

Sacubitril/valsartan ameliorates renal tubulointerstitial injury through increasing renal plasma flow in a mouse model of type 2 diabetes with aldosterone excess

BACKGROUND

Aldosterone has been assumed to be one of aggravating factors in diabetic kidney disease (DKD). Natriuretic peptides/guanylyl cyclase-A/cGMP signalling has been shown to ameliorate aldosterone-induced renal injury in mice. Sacubitril/valsartan (SAC/VAL) is used clinically for chronic heart failure and hypertension, in part by augmenting natriuretic peptide bioavailability. The effects of SAC/VAL on renal pathophysiology including in DKD, however, have remained unclarified.

METHODS

Eight-week-old male db/db mice fed on a high-salt diet (HSD) were treated with vehicle or aldosterone (0.2 μg/kg/min), and divided into four groups: HSD control, ALDO (aldosterone), ALDO + VAL (valsartan), and ALDO + SAC/VAL group. After 4 weeks, they were analysed for plasma atrial natriuretic peptide (ANP) levels, renal histology, and haemodynamic parameters including glomerular filtration rate (GFR) by FITC-inulin and renal plasma flow (RPF) by para-amino hippuric acid.

RESULTS

The ALDO + SAC/VAL group showed significantly increased plasma ANP concentration and creatinine clearance, and decreased tubulointerstitial fibrosis and neutrophil gelatinase-associated lipocalin expression compared to ALDO and ALDO + VAL groups. SAC/VAL treatment increased GFR and RPF, and suppressed expression of Tgfb1, Il1b, Ccl2, and Lcn2 genes compared to the ALDO group. The percentage of tubulointerstitial fibrotic areas negatively correlated with the RPF and GFR.

CONCLUSION

In a mouse model of type 2 diabetes with aldosterone excess, SAC/VAL increased RPF and GFR, and ameliorated tubulointerstitial fibrosis. Furthermore, RPF negatively correlated well with tubulointerstitial injury, suggesting that the beneficial effects of SAC/VAL could be through increased renal plasma flow with enhanced natriuretic peptide bioavailability.

A Current Landscape on Alport Syndrome Cases: Characterization, Therapy and Management Perspectives

Alport syndrome (AS) is a rare genetic disorder categorized by the progressive loss of kidney function, sensorineural hearing loss and eye abnormalities. It occurs due to mutations in three genes that encode for the alpha chains of type IV collagen. Globally, the disease is classified based on the pattern of inheritance into X-linked AS (XLAS), which is caused by pathogenic variants in COL4A5, representing 80% of AS. Autosomal recessive AS (ARAS), caused by mutations in either COL4A3 or COL4A4, represents 15% of AS. Autosomal dominant AS (ADAS) is rare and has been recorded in 5% of all cases due to mutations in COL4A3 or COL4A4. This review provides updated knowledge about AS including its clinical and genetic characteristics in addition to available therapies that only slow the progression of the disease. It also focuses on reported cases in Saudi Arabia and their prevalence. Moreover, we shed light on advances in genetic technologies like gene editing using CRISPR/Cas9 technology, the need for an early diagnosis of AS and managing the progression of the disease. Eventually, we provide a few recommendations for disease management, particularly in regions like Saudi Arabia where consanguineous marriages increase the risk.

Slowing the Progression of Diabetic Kidney Disease

Diabetes is the most frequent cause of kidney disease that progresses to end-stage renal disease worldwide, and diabetic kidney disease is significantly related to unfavorable cardiovascular outcomes. Since the 1990s, specific therapies have emerged and been approved to slow the progression of diabetic kidney disease, namely, renin-angiotensin-aldosterone system blockers (including angiotensin-converting enzyme inhibitors (ACEi) angiotensin receptor blockers (ARBs), the non-steroidal mineralocorticoid receptor antagonist (NS-MRA), finerenone, and sodium-glucose cotransporter-2 (SGLT2) inhibitors). Mechanistically, these different classes of agents bring different anti-inflammatory, anti-fibrotic, and complementary hemodynamic effects to patients with diabetic kidney disease such that they have additive benefits on slowing disease progression. Within the coming year, there will be data on renal outcomes using the glucagon-like peptide-1 receptor agonist, semaglutide. All the aforementioned medications have also been shown to improve cardiovascular outcomes. Thus, all three classes (maximally dosed ACEi or ARB, low-dose SGLT-2 inhibitors, and the NS-MRA, finerenone) form the "pillars of therapy" such that, when used together, they maximally slow diabetic kidney disease progression. Ongoing studies aim to expand these pillars with additional medications to potentially normalize the decline in kidney function and reduce associated cardiovascular mortality.

Finerenone: Questions and Answers-The Four Fundamental Arguments on the New-Born Promising Non-Steroidal Mineralocorticoid Receptor Antagonist

Chronic kidney disease (CKD) is one of the most common complications of diabetes mellitus and an independent risk factor for cardiovascular disease. Despite guideline-directed therapy of CKD in patients with type 2 diabetes, the risk of renal failure and cardiovascular events still remains high, and diabetes remains the leading cause of end-stage kidney disease in affected patients. To date, current medications for CKD and type 2 diabetes mellitus have not reset residual risk in patients due to a high grade of inflammation and fibrosis contributing to kidney and heart disease. This question-and-answer-based review will discuss the pharmacological and clinical differences between finerenone and other mineralocorticoid receptor antagonists and then move on to the main evidence in the cardiovascular and renal fields, closing, finally, on the potential role of therapeutic combination with sodium-glucose cotransporter 2 inhibitors (SGLT2is).

An analysis of DPV and DIVE registry patients with chronic kidney disease according to the finerenone phase III clinical trial selection criteria

BACKGROUND

The FIDELIO-DKD and FIGARO-DKD randomized clinical trials (RCTs) showed finerenone, a novel non-steroidal mineralocorticoid receptor antagonist (MRA), reduced the risk of renal and cardiovascular events in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD). Using RCT inclusion and exclusion criteria, we analyzed the RCT coverage for patients with T2DM and CKD in routine clinical practice in Germany.

METHODS

German patients from the DPV/DIVE registries who were ≥ 18 years, had T2DM and CKD (an estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m² OR eGFR ≥ 60 mL/min/1.73m² and albuminuria [≥ 30 mg/g]) were included. RCT inclusion and exclusion criteria were then applied, and the characteristics of the two populations compared.

RESULTS

Overall, 65,168 patients with T2DM and CKD were identified from DPV/DIVE. Key findings were (1) Registry patients with CKD were older, less often male, and had a lower eGFR, but more were normoalbuminuric vs the RCTs. Cardiovascular disease burden was higher in the RCTs; diabetic neuropathy, lipid metabolism disorders, and peripheral arterial disease were more frequent in the registry. CKD-specific drugs (e.g., angiotensin-converting enzyme inhibitors [ACEi] and angiotensin receptor blocker [ARBs]) were used less often in clinical practice; (2) Due to the RCT's albuminuric G1/2 to G4 CKD focus, they did not cover 28,147 (43.2%) normoalbuminuric registry patients, 4,519 (6.9%) albuminuric patients with eGFR < 25, and 6,565 (10.1%) patients with microalbuminuria but normal GFR (≥ 90 ml/min); 3) As RCTs required baseline ACEi or ARB treatment, the number of comparable registry patients was reduced to 28,359. Of these, only 12,322 (43.5%) registry patients fulfilled all trial inclusion and exclusion criteria. Registry patients that would have been eligible for the RCTs were more often male, had higher eGFR values, higher rates of albuminuria, more received metformin, and more SGLT-2 inhibitors than patients that would not be eligible.

CONCLUSIONS

Certain patient subgroups, especially non-albuminuric CKD-patients, were not included in the RCTs. Although recommended by guidelines, there was an undertreatment of CKD-patients with renin-angiotensin system (RAS) blockers. Further research into patients with normoalbuminuric CKD and a wider prescription of RAS blocking agents for CKD patients in clinical practice appears warranted.

Incorporating Evidence and Guidelines for Personalized Care of Diabetes and Chronic Kidney Disease

Chronic kidney disease (CKD) represents a particularly challenging diabetes complication. Diabetes now is responsible for half of all cases of CKD, thus making diabetes the most common cause of kidney failure worldwide. In patients with diabetes, CKD frequently coexists with heart failure and atherosclerotic cardiovascular disease, which together are associated with marked increases in the risk of cardiovascular and all-cause mortality. Fortunately, new therapeutic agents from several classes now are available with proven benefits for kidney and heart protection when used in patients with type 2 diabetes and CKD. Agents from the sodium-glucose cotransporter-2 inhibitor, glucagon-like peptide-1-receptor agonist, and nonsteroidal mineralocorticoid-receptor antagonist classes now are considered standard of care to improve kidney, heart, and overall survival outcomes in patients with type 2 diabetes. Efforts to educate health care providers on the benefits of these therapies are critically needed to help increase their utilization and improve clinical outcomes. Care decisions should be driven by a holistic view of patient priorities and goals with consideration of a multimodal therapeutic approach to maximize heart and kidney benefits.

[Mineralocorticoid receptor antagonists: A new therapeutic option for diabetic kidney disease]

Diabetic kidney disease (DKD) and its associated cardiovascular morbidity represent a major complication in diabetic patients. Over the past two decades, several experimental studies have shown benefits of mineralocorticoid receptor (MR) antagonists on the cardiorenal outcomes in animal models of non-diabetic or diabetic kidney diseases. Here, we summarize the role of MR activation in promoting inflammatory and fibrotic mechanisms that contribute to DKD pathophysiology. We also review the key findings of two recent large clinical trials FIDELIO-DKD and FIGARO-DKD which showed for the first time a major benefit of the non-steroidal MR antagonist, finerenone, on renal and cardiac specific outcomes across the spectrum of DKD severity. We finally discuss the place of finerenone compared to other DKD therapeutic approaches.

Renin, aldosterone, the aldosterone-to-renin ratio, and incident hypertension among normotensive subjects from the general population

AIMS

To investigate the predictive ability of direct plasma renin and aldosterone concentrations as well as their ratio [aldosterone-to-renin (ARR)] for incident hypertension in the general population.

METHODS AND RESULTS

Concentration of renin and aldosterone were measured by a chemiluminescence immunoassay using the fully automated LIAISON® platform (DiaSorin) among 5362 participants of the population-based Gutenberg Health Study, who were normotensive and had no clinically overt cardiovascular disease at baseline. During a follow-up period of 5 years, 18.6% (n = 996) developed a new-onset hypertension. Comparing extreme quartiles of biomarker distribution, the relative risk (RR) for incident arterial hypertension was found to be 1.58 [95% confidence interval (CI) 1.25-2.00; P = 0.00015; Q1 vs. Q4ref] for renin; 1.29 (95% CI 1.05-1.59, P = 0.018; Q4 vs. Q1ref) for aldosterone and 1.70 (95% CI 1.33-2.12; P < 0.0001; Q4 vs. Q1ref) for ARR after multivariable adjustment in men. In females, only high ARR was independently predictive for incident hypertension over 5 years [RR 1.29 (95% CI 1.04-1.62); P = 0.024]. Even in the subgroup of individuals having biomarker concentrations within the reference range, high ARR was predictive for new-onset hypertension in men [RR 1.44 (95% CI 1.13-1.83); P = 0.003]. Finally, synergistic effects of co-prevalent obesity and ARR on incident hypertension were also demonstrated, resulting in markedly higher risk estimates as seen for biomarker alone [RR of 2.70 (95% CI 2.05-3.6) for Q4 of ARR and having body mass index ≥ 30 kg/m2 vs. low ARR (Q1ref) and normal weight; P < 0.0001].

CONCLUSION

Among normotensives from the general population ARR possesses a stronger predictive value for incident hypertension than renin or aldosterone alone. The prediction of arterial hypertension by ARR was even stronger in obese subjects.

N-/T-Type vs. L-Type Calcium Channel Blocker in Treating Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Renin-angiotensin system (RAS) inhibitors and calcium channel blockers (CCB) are often used together in chronic kidney disease (CKD). The PubMed, EMBASE, and Cochrane Library databases were searched to identify randomized controlled trials (RCTs) in order to explore better subtypes of CCB for the treatment of CKD. This meta-analysis of 12 RCTs with 967 CKD patients who were treated with RAS inhibitors demonstrated that, when compared with L-type CCB, N-/T-type CCB was superior in reducing urine albumin/protein excretion (SMD, −0.41; 95% CI, −0.64 to −0.18; p < 0.001) and aldosterone, without influencing serum creatinine (WMD, −3.64; 95% CI, −11.63 to 4.35; p = 0.37), glomerular filtration rate (SMD, 0.06; 95% CI, −0.13 to 0.25; p = 0.53), and adverse effects (RR, 0.95; 95% CI, 0.35 to 2.58; p = 0.93). In addition, N-/T-type CCB did not decrease the systolic blood pressure (BP) (WMD, 0.17; 95% CI, −1.05 to 1.39; p = 0.79) or diastolic BP (WMD, 0.64; 95% CI, −0.55 to 1.83; p = 0.29) when compared with L-type CCB. In CKD patients treated with RAS inhibitors, N-/T-type CCB is more effective than L-type CCB in reducing urine albumin/protein excretion without increased serum creatinine, decreased glomerular filtration rate, and increased adverse effects. The additional benefit is independent of BP and may be associated with decreased aldosterone (PROSPERO, CRD42020197560).

Results From a Randomized, Open-Label, Crossover Study Evaluating the Effect of the Aldosterone Synthase Inhibitor Baxdrostat on the Pharmacokinetics of Metformin in Healthy Human Subjects

BACKGROUND

Due to the high comorbidity of diabetes and hypertension, co-administration of metformin with anti-hypertensive drugs is likely. Baxdrostat is an aldosterone synthase inhibitor in development for the potential treatment of hypertension. In vitro data indicated that baxdrostat inhibits the multidrug and toxin extrusion 1 (MATE1) and MATE2-K renal transporters. Metformin is a MATE substrate, so this study assessed potential effects of baxdrostat on the pharmacokinetics of metformin.

METHODS

Twenty-seven healthy volunteers received 1000 mg metformin alone and 1000 mg metformin in the presence of 10 mg baxdrostat in a randomized, crossover manner. Each treatment was separated by 10 or more days. Blood and urine samples were collected over a 3-day period after each treatment to measure plasma and urine concentrations of metformin. Safety was assessed by adverse events (AEs), physical examinations, electrocardiograms, vital signs, and clinical laboratory evaluations.

RESULTS

There were no deaths, serious AEs, discontinuations due to treatment-emergent AEs, or noteworthy increases in AEs with either treatment, indicating that metformin and baxdrostat were well-tolerated when co-administered. Baxdrostat did not significantly affect plasma concentrations or renal clearance of metformin.

CONCLUSION

The results of this study suggest that diabetic patients with hypertension receiving both metformin and baxdrostat are unlikely to require dose adjustment.

REGISTRATION

ClinicalTrials.gov identifier no. NCT05526690.

The CARDINAL Trial of Bardoxolone Methyl in Alport Syndrome: When Marketing Interests Prevail over Patients Clinical Needs

CONTEXT

Alport syndrome (AS) is a hereditary chronic kidney disease (CKD) with X-linked, autosomal, and digenic patterns of transmission. Sieving dysfunction of the glomerular basement membrane caused by congenitally defective type IV collagen results in persistent proteinuria, hematuria, and progressive renal dysfunction. There are no disease-specific medications and treatment is based on conservative interventions in particular with renin-angiotensin-aldosterone-system (RAAS) inhibitors. Subject of Review: Evidence that AS is accompanied by glomerular and tubular inflammatory changes and that bardoxolone methyl exerts anti-inflammatory effects through suppression of NF-kB and activation of transcription of antioxidant and anti-inflammatory genes, provided a justification for the CARDINAL study, a prospective, randomized controlled trial testing the potential renoprotective effect of bardoxolone methyl in 157 adolescent or adult patients with AS. The authors concluded that bardoxolone methyl preserved estimated glomerular filtration rate (eGFR) relative to placebo at 48 and 100 weeks after randomization. However, exactly the same number of patients (n = 3) in each group developed kidney failure. Second Opinion: Despite alarming safety signals from previous trials in type 2 diabetics with CKD (increased hospitalizations for heart failure, fatal and nonfatal cardiovascular events, liver toxicity, and increased blood pressure and albuminuria), major marketing interests encouraged the drug manufacturer to pursue this line of research. Finding that type IV collagen gene mutations account for nearly one-third of cases of hereditary glomerulopathies implies that the population of potential target-patients could probably be much larger than estimated. Moreover, any new medication approved for AS might receive orphan drug designation which might be associated with shortened time to approval, monetary benefits, and a period of market exclusivity. In actual facts, CARDINAL failed to demonstrate any nephro-protective effect of bardoxolone methyl and found an increase in liver enzymes in 70 of the 77 (90.9%) bardoxolone-treated patients consistent with chronic liver toxicity. Indeed, in Zucker diabetic fatty rats treated with an analog of bardoxolone methyl, elevations of liver aminotransferases were associated with enhanced liver weight, severe and diffuse hepatocyte vacuolization, swelling, and degeneration. Moreover, bardoxolone-induced increase in eGFR was associated with a concomitant increase in geometric mean urinary albumin/creatinine ratio, a finding consistent with worsening glomerular hyperfiltration. Considering also the consequent increase in the biomechanical strain on the fragile Alport glomerular basement membrane, this hemodynamic effect is expected to translate into accelerated renal disease progression (consistently with evidence that a bardoxolone methyl analog worsened proteinuria, glomerulosclerosis, and tubular damage in Zucker diabetic fatty rats). These concerns induced the Food and Drug Administration to reject the new drug application for bardoxolone methyl submitted by Reata Pharmaceuticals, Inc. with the proposed indication to slow CKD progression in AS patients 12 years of age and older. Thus, bardoxolone methyl is devoid of any nephro-protective effect and is associated with significant heart, liver, and renal toxicity in patients with CKD, including those with AS. Because of these safety signals, it should not be used in this clinical context. Research programs could explore the potential clinical applications, even outside the kidney field, of novel NF erythroid 2-like 2 modulators devoid of bardoxolone methyl toxicity.

Research Progress on the Efficacy and Safety of Spironolactone in Reversing Left Ventricular Hypertrophy in Hemodialysis Patients

The mineralocorticoid receptor antagonist spironolactone has been shown to improve cardiac function and reverse left ventricular hypertrophy in heart failure patients, but there are no consistent findings on the efficacy and safety in hemodialysis patients. Abnormal aldosterone secretion plays a critical role in the formation of left ventricular hypertrophy. Because of the existence of "aldosterone escape", the routine use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers does not completely inhibit aldosterone secretion. Low-dose spironolactone (25 mg/d) has been found in small-sample clinical studies to have a significant positive impact with respect to decreasing left ventricular mass index, increasing left ventricular ejection fraction, reversing left ventricular hypertrophy, and improving cardiovascular function while still being safe. More prospective multicenter clinical trials with large sample sizes are needed, however, to provide convincing evidence.

Results from a phase 1, randomized, double-blind, multiple ascending dose study characterizing the pharmacokinetics and demonstrating the safety and selectivity of the aldosterone synthase inhibitor baxdrostat in healthy volunteers

Baxdrostat is a selective inhibitor of aldosterone synthase designed for the treatment of disorders associated with elevated aldosterone. This study evaluated the safety, pharmacokinetics, and pharmacodynamics of multiple ascending doses of baxdrostat in healthy volunteers. Subjects were randomized to receive oral baxdrostat (0.5, 1.5, 2.5, or 5.0 mg) or placebo once daily for 10 days and were placed on either a low-salt or normal-salt diet for the duration of the study. Blood samples were collected before and after dosing on days 1 and 10 to characterize pharmacokinetics and pharmacodynamics. Safety was assessed by adverse events, physical examinations, electrocardiograms, orthostatic vital signs, and clinical laboratory evaluations. Fifty-four subjects completed the study. There were no deaths or serious adverse events, and all treatment-emergent adverse events in subjects receiving baxdrostat were mild in severity. Plasma levels of baxdrostat increased proportionally with ascending doses, with peak concentrations observed within 4 h after dosing and a mean half-life of 26 to 31 h. A dose-dependent reduction of plasma aldosterone occurred with baxdrostat doses ≥1.5 mg, regardless of diet. Decreases in plasma aldosterone were sustained, with levels reduced by approximately 51 to 73% on day 10. Baxdrostat had no meaningful impact on plasma cortisol levels and resulted in mild dose-dependent decreases in plasma sodium levels and increases in potassium levels. Baxdrostat was safe and well tolerated with a half-life that supports once-daily dosing. The dose-dependent reduction in plasma aldosterone and lack of effect on cortisol demonstrate the selective blockade of aldosterone synthase.

Chronic kidney disease in patients with type 2 diabetes: new targets of medicine action

Diabetes mellitus type 2 (DM2) is socially important disease, becoming non-infectious epidemic due to increasing prevalence. Chronic kidney disease (CKD) is one of the most common diabetic complications. Kidney injury signs and/or estimated glomerular filtration rate (eGFR) decrease are seen in 40-50% of patients with DM2. Three groups of factors are considered to be the basis of CKD development and progression in DM2: metabolic, hemodynamic, inflammation and fibrosis. Existing drugs that are used in patients with CKD and DM2 first of all target hemodynamic and metabolic disturbances, but their action against inflammation and fibrosis is indirect. Hyperactivation of mineralocorticoid receptors (MR) is considered as one of the main trigger factors of end-organ damage in patients with DM2 due to inflammation and fibrosis. Development of selective nonsteroidal MR antagonists (MRA) as a new class of medications is directed to demonstrate positive effects from blocking this pathophysiological pathway of CKD development and overcome the steroidal MRAs’ shortcomings. Hence pathophysiological hyperactivation of MR with subsequent inflammation and fibrosis in patients with CKD in DM2 is considered a promising therapeutic target for the new drugs with cardionephroprotective effect.

Evolution of Mineralocorticoid Receptor Antagonists in the Treatment of Chronic Kidney Disease Associated with Type 2 Diabetes Mellitus

Chronic kidney disease (CKD) is one of the most frequent complications associated with type 2 diabetes mellitus (T2DM) and is also an independent risk factor for cardiovascular disease. The mineralocorticoid receptor (MR) is a nuclear receptor expressed in many tissue types, including kidney and heart. Aberrant and long-term activation of MR by aldosterone in patients with T2DM triggers detrimental effects (eg, inflammation and fibrosis) in these tissues. The suppression of aldosterone at the early stage of T2DM has been a therapeutic strategy for patients with T2DM-associated CKD. Although patients have been treated with renin-angiotensin system (RAS) blockers for decades, RAS blockers alone are not sufficient to prevent CKD progression. Steroidal MR antagonists (MRAs) have been used in combination with RAS blockers; however, undesired adverse effects have restricted their usage, prompting the development of nonsteroidal MRAs with better target specificity and safety profiles. Recently conducted studies, Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease (FIDELIO-DKD) and Finerenone in Reducing Cardiovascular Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD), have reported that finerenone, a nonsteroidal MRA, improves both renal and cardiovascular outcomes compared with placebo. In this article, we review the history of MRA development and discuss the possibility of its combination with other treatment options, such as sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and potassium binders for patients with T2DM-associated CKD.

Angiotensinogen: More Than its Downstream Products: Evidence From Population Studies and Novel Therapeutics

The renin-angiotensin-aldosterone system (RAAS) is a well-defined pathway playing a key role in maintaining circulatory homeostasis. Abnormal activation of RAAS contributes to development of cardiovascular disease, including heart failure, cardiac hypertrophy, hypertension, and atherosclerosis. Although several key RAAS enzymes and peptide hormones have been thoroughly investigated, the role of angiotensinogen-the precursor substrate of the RAAS pathway-remains less understood. The study of angiotensinogen single-nucleotide polymorphisms (SNPs) has provided insight into associations between angiotensinogen and hypertension, congestive heart failure, and atherosclerotic cardiovascular disease. Targeted drug therapy of RAAS has dramatically improved clinical outcomes for patients with heart failure, myocardial infarction, and hypertension. However, all such therapeutics block RAAS components downstream of angiotensinogen and elicit compensatory pathways that limit their therapeutic efficacy as monotherapy. Upstream RAAS targeting by an angiotensinogen inhibitor has the potential to be more efficacious in patients with suboptimal RAAS inhibition and has a better safety profile than multiagent RAAS blockade. Newly developed therapeutics that target angiotensinogen through antisense oligonucleotides or silencer RNA technologies are providing a novel perspective into the pathobiology of angiotensinogen and show promise as the next frontier in the treatment of cardiovascular disease.

Mineralocorticoid receptor antagonists for cardioprotection in chronic kidney disease: a step into the future

Chronic kidney disease (CKD) and cardiovascular disease (CVD) share major risk factors and mechanistic pathways for progression. Furthermore, either decreased glomerular filtration rate or increased albuminuria are major risk factors for cardiovascular events. Evidence from previous renal outcome trials in patients with proteinuric CKD showed that angiotensin-converting-enzyme inhibitors (ACEIs) and angiotensin-II receptor blockers (ARBs) effectively slow CKD progression, establishing these agents as fundamental CKD pharmacologic treatments. However, in all these trials and subsequent meta-analyses, ACEIs and ARBs did not significantly reduce cardiovascular events or mortality, indicating a high residual risk for CVD progression in individuals with CKD. In contrast to the above, several outcome trials with old and novel mineralocorticoid receptor-antagonists (MRAs) clearly suggest that these agents, apart from nephroprotection, offer important cardioprotection in this population. This article is an overview of previous and recent evidence on the effects of MRAs on cardiovascular outcomes in patients with CKD attempting to highlight a pathway able to improve both cardiovascular and renal prognosis in this population.

New Strategies for Volume Control in Patients with Diabetes Mellitus, a Narrative Review

Sodium is reabsorbed all along the renal tubules. The positive impacts of sodium-glucose cotransporter-2 inhibitors (SGLT2i), angiotensin receptor neprilysin inhibitor (ARNI) and mineralocorticoid receptor antagonists (MRA) on hard renal and/or cardiac endpoints calls for the role of diuretics in nephroprotection and cardioprotection in patients with diabetes mellitus to be reviewed. Here, we review: (a) the mechanisms of action of the available natriuretics; (b) the physiological adaptations to chronic loop diuretic usage that lead to increased sodium reabsorption in the proximal and distal convoluted tubules; (c) the physiology of sodium retention in patients with diabetes mellitus; and (d) the mechanisms of aldosterone breakthrough. We show the rationale for combined diuretics to target not only the loop of Henle, but also the proximal and distal convoluted tubules. Indeed, higher residual proteinuria in patients treated with renin-angiotensin-aldosterone system (RAAS) blockers portends poorer renal and cardiovascular outcomes. Diuretics are known to optimize the reduction of proteinuria, in addition to RAAS blockers, but may favor aldosterone breakthrough in the absence of MRA. The aim of our study is to support a combined diuretics strategy to improve the management of patients with diabetes mellitus and chronic kidney disease or heart failure.

Modifying chronic kidney disease progression with the mineralocorticoid receptor antagonist finerenone in patients with type 2 diabetes

In patients with type 2 diabetes, chronic kidney disease (CKD) is the most common cause of kidney failure. With its increasing prevalence and limited treatment options, CKD is a major contributor to the global burden of disease. Although recent guidelines for the control of hypertension and hyperglycaemia, as well as the use of renin-angiotensin system inhibitors and, more recently, sodium-glucose co-transporter-2 inhibitors, have improved outcomes for patients with CKD and diabetes, there is still a high residual risk of CKD progression and adverse cardiovascular events. In this review, we discuss the recently published FIDELIO-DKD and FIGARO-DKD studies and FIDELITY prespecified individual patient analysis. Together, these studies have established finerenone, a novel non-steroidal mineralocorticoid receptor antagonist, as an effective treatment for kidney and cardiovascular protection and welcome addition to the pillars of treatment to slow CKD progression in patients with type 2 diabetes.

Clinical effect of nonsteroidal mineralocorticoid receptor (MR) antagonists in the treatment of diabetic kidney disease: expectations as a new therapeutic strategy

Diabetes mellitus is the main cause of chronic kidney disease (CKD) in Japan and worldwide. Although angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor blockers (ARBs) are basic drugs for the treatment of CKD with diabetes (diabetic kidney disease, DKD) with albuminuria and/or proteinuria, it has also become clear that the use of an ACE inhibitor or ARB alone is not fully sufficient. We have previously reported the clinical effects of mineralocorticoid receptor (MR) antagonists and recommended their use in addition to renin-angiotensin system inhibitors. Recently, new types of nonsteroidal MR antagonists have been developed, and the results of a large-scale study are expected. Nonsteroidal MR antagonists are distributed in the heart, lungs, liver, and kidneys when administered orally and are characterized by their equivalent distribution between the heart (nonepithelial tissue) and kidneys (epithelial tissue). We summarize the latest evidence regarding the use of nonsteroidal MR antagonists in the treatment of DKD. Hyperkalemia and renal dysfunction are frequent during MR antagonist treatment. However, with careful and combined monitoring of these two conditions, the effectiveness of MR antagonists will not be diminished; conversely, it is apparent that patients at such risk will benefit more from the addition of an MR antagonist to the treatment regimen. The most important measure against hyperkalemia is the regular monitoring of serum potassium levels and renal function. The safest and most reliable measure against hyperkalemia is the combined use of a new oral potassium adsorbent that has high potassium selectivity and few side effects. In DKD treatment, it is important to continue using MR antagonists without interruption as much as possible.

Discovery of Apararenone (MT-3995) as a Highly Selective, Potent, and Novel Nonsteroidal Mineralocorticoid Receptor Antagonist

Overactivation of the mineralocorticoid receptor (MR) is involved in many diseases, such as hypertension, kidney disease, and heart failure. Thus, MR antagonists (MRAs) are expected to be beneficial to patients with these diseases. In order to identify novel nonsteroidal MRAs that overcome the issues of already marketed steroidal MRAs, we searched for new compounds guided by our hypothesis that T-shaped compounds with a hydrophobic core structure, two polar functional groups at both extremities able to interact with MR, and a bulky substituent that can interfere with the folding of the C-terminal helix 12 may exhibit antagonist activity toward MR. We discovered that the novel 1,4-benzoxazin-3-one derivative 19 (apararenone: MT-3995) acted as a highly selective and potent nonsteroidal MRA. Apararenone exhibited a more potent antihypertensive and organ-protective activity than steroidal MRA eplerenone in a primary aldosteronism rat model obtained by infusing aldosterone in uninephrectomized rats.

Molecular Mechanisms and Therapeutic Targets for Diabetic Kidney Disease

Diabetic kidney disease has a high global disease burden and substantially increases risk of kidney failure and cardiovascular events. Despite treatment, there is substantial residual risk of disease progression with existing therapies. Therefore, there is an urgent need to better understand the molecular mechanisms driving diabetic kidney disease to help identify new therapies that slow progression and reduce associated risks. Diabetic kidney disease is initiated by diabetes-related disturbances in glucose metabolism, which then trigger other metabolic, hemodynamic, inflammatory, and fibrotic processes that contribute to disease progression. This review summarizes existing evidence on the molecular drivers of diabetic kidney disease onset and progression, focusing on inflammatory and fibrotic mediators-factors that are largely unaddressed as primary treatment targets and for which there is increasing evidence supporting key roles in the pathophysiology of diabetic kidney disease. Results from recent clinical trials highlight promising new drug therapies, as well as a role for dietary strategies, in treating diabetic kidney disease.

Aldosterone breakthrough from a pharmacological perspective

Aldosterone (Aldo) breakthrough is a well-known phenomenon that occurs in patients with long-term renin-angiotensin aldosterone system (RAAS) blockade using inhibitors of renin or angiotensin converting enzyme or angiotensin II type 1 receptor blockers. The blockade of the mineralocorticoid receptor (MR), an Aldo binding receptor, is effective in managing patients with resistant hypertension, defined as uncontrollable blood pressure despite the concurrent use of three antihypertensive drugs. In other words, MR inhibitors are not used as first-line antihypertensive drugs in most guidelines for hypertension management. Aldo breakthrough puts hypertensive patients at higher risk of cardiovascular disease and worsens future outcomes. This review discusses Aldo secretion and the mechanism of Aldo breakthrough, dependent or independent of the RAAS, with consideration of the pharmacological aspects of this phenomenon, as well as hypothetical views.

Renin-Angiotensin-Aldosterone System Activation and Diuretic Response in Ambulatory Patients With Heart Failure

Rationale & Objective

Heart failure treatment relies on loop diuretics to induce natriuresis and decongestion, but the therapy is often limited by diuretic resistance. We explored the association of renin-angiotensin-aldosterone system (RAAS) activation with diuretic response.

Study Design

Observational cohort.

Setting & Population

Euvolemic ambulatory adults with chronic heart failure were administered torsemide in a monitored environment.

Predictors

Plasma total renin, active renin, angiotensinogen, and aldosterone levels. Urine total renin and angiotensinogen levels.

Outcomes

Sodium output per doubling of diuretic dose and fractional excretion of sodium per doubling of diuretic dose.

Analytical Approach

Robust linear regression models estimated the associations of each RAAS intermediate with outcomes.

Results

The analysis included 56 participants, and the median age was 65 years; 50% were women, and 41% were Black. The median home diuretic dose was 80-mg furosemide equivalents. In unadjusted and multivariable-adjusted models, higher levels of RAAS measures were generally associated with lower diuretic efficiency. Higher plasma total renin remained significantly associated with lower sodium output per doubling of diuretic dose (β = -0.41 [-0.76, -0.059] per SD change) with adjustment; higher plasma total and active renin were significantly associated with lower fractional excretion of sodium per doubling of diuretic dose (β = -0.48 [-0.83, -0.14] and β = -0.51 [-0.95, -0.08], respectively) in adjusted models. Stratification by RAAS inhibitor use did not substantially alter these associations.

Limitations

Small sample size; highly selected participants; associations may not be causal.

Conclusions

Among multiple measures of RAAS activation, higher plasma total and active renin levels were consistently associated with lower diuretic response. These findings highlight the potential drivers of diuretic resistance and underscore the need for high-quality trials of decongestive therapy enhanced by RAAS blockade.

Novel Therapies for Alport Syndrome

Alport syndrome (AS) is a hereditary kidney disease associated with proteinuria, hematuria and progressive kidney failure. It is characterized by a defective glomerular basement membrane caused by mutations in type IV collagen genes COL4A3/A4/A5 which result in defective type IV collagen α3, α4, or α5 chains, respectively. Alport syndrome has three different patterns of inheritance: X-linked, autosomal and digenic. In a study of CKD of unknown etiology type IV collagen gene mutations accounted for the majority of the cases of hereditary glomerulopathies which suggests that AS is often underrecognized. The natural history and prognosis in patients with AS is variable and is determined by genetics and environmental factors. At present, no preventive or curative therapies exist for AS. Current treatment includes the use of renin-angiotensin-aldosterone system inhibitors which slow progression of kidney disease and prolong life expectancy. Ramipril was found in retrospective studies to delay the onset of ESKD and was recently demonstrated to be safe and effective in children and adolescents, supporting that early initiation of Renin Angiotensin Aldosterone System (RAAS) blockade is very important. Mineralocorticoid receptor blockers might be favorable for patients who develop "aldosterone breakthrough." While the DAPA-CKD trial suggests a beneficial effect of SGLT2 inhibitors in CKD of non-metabolic origin, only a handful of patients had Alport in this cohort, and therefore conclusions can't be extrapolated for the treatment of AS with SGLT2 inhibitors. Advances in our understanding on the pathogenesis of Alport syndrome has culminated in the development of innovative therapeutic approaches that are currently under investigation. We will provide a brief overview of novel therapeutic targets to prevent progression of kidney disease in AS. Our review will include bardoxolone methyl, an oral NRf2 activator; lademirsen, an anti-miRNA-21 molecule; sparsentan, dual endothelin type A receptor (ETAR) and angiotensin 1 receptor inhibitor; atrasentan, oral selective ETAR inhibitor; lipid-modifying agents, including cholesterol efflux transporter ATP-binding cassette A1 (ABCA1) inducers, discoidin domain receptor 1 (DDR1) inhibitors and osteopontin blocking agents; the antimalarial drug hydroxychloroquine; the antiglycemic drug metformin and the active vitamin D analog paricalcitol. Future genomic therapeutic strategies such as chaperone therapy, genome editing and stem cell therapy will also be discussed.

Mineralocorticoid Receptor Antagonists in the Treatment of Diabetic Kidney Disease: Their Application in the Era of SGLT2 Inhibitors and GLP-1 Receptor Agonists

PURPOSE OF REVIEW

This review focuses on new clinical data involving a novel class of drugs, nonsteroidal mineralocorticoid receptor antagonists (NS-MRAs), specifically, finerenone and its effects on cardiovascular and diabetic kidney disease outcomes.

RECENT FINDINGS

NS-MRAs are a novel class of agents for treating diabetic kidney disease (DKD). While they are chemically and pharmacologically distinct from steroidal MRAs (spironolactone, eplerenone), they effectively inhibit the MR receptor differently. Inhibition of MR receptor activation reduces inflammatory and profibrotic pathways involving the cardiorenal/vascular systems. Small diabetic kidney disease (DKD) clinical studies demonstrate that steroidal MRAs reduce albuminuria relative to placebo, although hyperkalemia is a major adverse event that has precluded large outcome trials. The NS-MRA, finerenone, demonstrated slowed progression of DKD and reduction of cardiovascular death primarily driven by reduced heart failure incidence in two separate randomized controlled clinical trials (FIDELIO and FIGARO). Use of NS-MRAs, therefore, provides a third "pillar of therapy" to reduce cardiorenal events added to blockers of the renin-angiotensin system and SGLT2 inhibitors. If the pending outcome trial, FLOW, is positive, potentially, GLP1-RAs may also be part of this "pillar" structure.

Efficacy and safety of a low-sodium diet and spironolactone in patients with stage 1-3a chronic kidney disease: a pilot study

Background

Excessive salt intake is associated with the deterioration of chronic kidney disease (CKD). Aldosterone is also known as an independent risk factor for kidney injury. Dietary sodium intake acts as a main stimulator in aldosterone-mediated kidney injury. Hence, this study aimed to further investigate the renal protective effects and safety of a low-sodium diet in combination with spironolactone (SPL) in stage 1-3a CKD.

Methods

This single-center, SPL-blinded randomized controlled trial recruited patients with stage 1-3a CKD, randomized into three groups, low-sodium (3 g/d salt) + placebo, medium-sodium (5 g/d salt) + SPL, and low-sodium (3 g/d salt) + SPL. Patients received 12 weeks of intervention. The primary and secondary endpoints were 24-h urine protein and estimated glomerular filtration rate (eGFR) at the end of the intervention, respectively.

Results

A total of 74 patients were analyzed eventually. Significantly decreased 24-h urine protein was found in all three groups, from 0.37 to 0.23 g/d (P = 0.004) in the low-sodium+placebo group, from 0.44 to 0.29 g/d (P = 0.020) in the medium-sodium+SPL group, and from 0.35 to 0.31 g/d (P = 0.013) in the low-sodium +SPL group. There were no significant differences among the three groups in 24-h urine protein amount change after intervention from pre-treatment values (P = 0.760, ITT set). The results of the 24-h urine protein by using PP set analysis was similar to the ITT set. No significant differences in eGFR, nutritional, metabolic, inflammatory, and other biomarkers were observed across all three groups (P > 0.05). No safety signal was observed.

Conclusion

No additional benefit was observed when SPL was prescribed to patients already on a low-sodium diet (3.0 g/d). Still, small doses of SPL may benefit patients with poor sodium restriction. A combination of short-term low-dose SPL and ARB is safe for patients with stage 1-3a CKD, but blood potassium must be regularly monitored.

Trial registration

Name of the registry: Chinese clinical trial registry.

Trial registration number: ChiCTR1900026991.

Date of registration: Retrospectively registered 28 October 2019.

URL of trial registry record: http://www.chictr.org.cn/searchproj.aspx?title=&officialname=&subjectid=&secondaryid=&applier=&studyleader=ðicalcommitteesanction=&spo

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02711-z.

Improving the residual risk of renal and cardiovascular outcomes in diabetic kidney disease: A review of pathophysiology, mechanisms, and evidence from recent trials

Based on global estimates, almost 10% of adults have diabetes, of whom 40% are estimated to also have chronic kidney disease (CKD). Almost 2 decades ago, treatments targeting the renin-angiotensin system (RAS) were shown to slow the progression of kidney disease. More recently, studies have reported the additive benefits of antihyperglycaemic sodium-glucose co-transporter-2 inhibitors in combination with RAS inhibitors on both CKD progression and cardiovascular outcomes. However, these recent data also showed that patients continue to progress to kidney failure or die from kidney- or cardiovascular-related causes. Therefore, new agents are needed to address this continuing risk. Overactivation of the mineralocorticoid (MR) receptor contributes to kidney inflammation and fibrosis, suggesting that it is an appropriate treatment target in patients with diabetes and CKD. Novel, selective non-steroidal MR antagonists are being studied in these patients, and the results of two large recently completed clinical trials have shown that one such treatment, finerenone, significantly reduces CKD progression and cardiovascular events compared with standard of care. This review summarizes the pathogenic mechanisms of CKD in type 2 diabetes and examines the potential benefit of novel disease-modifying agents that target inflammatory and fibrotic factors in these patients.

Can patiromer allow for intensified renin-angiotensin-aldosterone system blockade with losartan and spironolactone leading to decreased albuminuria in patients with chronic kidney disease, albuminuria and hyperkalaemia? An open-label randomised controlled trial: MorphCKD

INTRODUCTION

Chronic kidney disease (CKD) is associated with significantly increased morbidity and mortality. No specific treatment of the underlying condition is available for the majority of patients, but ACE-inhibitors (ACE-I) and angiotensin II-receptor blockers (ARB) slows progression in albuminuric CKD. Adding a mineralocorticoid receptor-antagonist (MRA) like spironolactone has an additive effect. However, renin-angiotensin-aldosterone system (RAAS)-blockade increases the risk of hyperkalaemia which is exacerbated by the presence of CKD. Thus, hyperkalaemia may prevent optimal use of RAAS-blockade in some patients.This project hypothesises that adding a potassium binder (patiromer) allows for improved RAAS-blockade including the use of MRA, thereby reducing albuminuria in patients with albuminuric CKD where full treatment is limited by hyperkalaemia.If successful, the study may lead to improved treatment of this subgroup of patients with CKD. Furthermore, the study will examine the feasibility of potassium binders in patients with CKD.

METHODS AND ANALYSIS

An open-label, randomised controlled trial including 140 patients with estimated glomerular filtration rate (eGFR) 25-60 mL/min/1.73 m², a urinary albumin/creatinine ratio (UACR) >500 mg/g (or 200 mg/g if diabetes mellitus) and a current or two previous plasma-potassium >4.5 mmol/L. Patients who develop hyperkaliaemia >5.5 mmol/L during a run-in phase, in which RAAS-blockade is intesified with the possible addition of spironolactone, are randomised to 12-month treatment with maximal tolerated ACE-I/ARB and spironolactone with or without patiromer.The primary endpoint is the difference in UACR measured at randomisation and 12 months compared between the two groups. Secondary endpoints include CKD progression, episodes of hyperkalaemia, blood pressure, eGFR, markers of cardiovascular disease, diet and quality of life.

ETHICS AND DISSEMINATION

This study is approved by The Central Denmark Region Committees on Health Research Ethics (REFNO 1-10-72-110-20) and is registered in the EudraCT database (REFNO 2020-001595-15). Results will be presented in peer-reviewed journals, at meetings and at international conferences.

Kinin B1 Receptor Mediates Renal Injury and Remodeling in Hypertension

Despite many readily available therapies, hypertensive kidney disease remains the second most prevalent cause of end-stage renal disease after diabetes, and continues to burden patient populations and escalate morbidity and mortality rates. Kinin B1 receptor (B1R) activation has been shown to have a role in the development of hypertension, one of the major etiologies for chronic kidney disease. However, the role of B1R in hypertension induced renal injury and remodeling remains unexplored. Using a DOCA-salt-induced hypertensive mouse model, we investigated whether B1R deficiency reduces hypertensive renal injury and fibrosis. To further recognize the translational role of B1R, we examined the expression of B1R and its correlation with collagen deposition in renal biopsies from control and hypertensive kidney disease patients. Our data indicates that renal B1R expression was upregulated in the kidneys of DOCA-salt hypertensive mice. Genetic ablation of B1R protected the mice from DOCA-salt-induced renal injury and fibrosis by preventing inflammation and oxidative stress in the kidney. Cultured human proximal tubular epithelial cells expressed B1R and stimulation of B1R with an agonist resulted in increased oxidative stress. In human kidney biopsy samples, we found that the B1R immunoreactivity was not only significantly increased in hypertensive patients compared to normotensive patients, but also there is a positive correlation between B1R expression and renal fibrosis levels. Taken together, our results identify a critical role of B1R in the development of inflammation and fibrosis of the kidney in hypertension.

Mineralocorticoid Receptor Antagonist Use and Hard Renal Outcomes in Real-World Patients With Chronic Kidney Disease

BACKGROUND

Real-world evidence about mineralocorticoid receptor antagonist (MRA) use has been limited in chronic kidney disease, particularly regarding its association with hard renal outcomes.

METHODS

In this retrospective cohort study, adult chronic kidney disease outpatients referred to the department of nephrology at an academic hospital between January 2005 and December 2018 were analyzed. The main inclusion criteria were estimated glomerular filtration rate ≥10 and <60 mL/min per 1.73 m² and follow-up ≥90 days. The exposure of interest was MRA use, defined as the administration of spironolactone, eplerenone, or potassium canrenoate. The primary outcome was renal replacement therapy initiation, defined as the initiation of chronic hemodialysis, peritoneal dialysis, or kidney transplantation. A marginal structural model using inverse probability of weighting was applied to account for potential time-varying confounders.

RESULTS

Among a total of 3195 patients, the median age and estimated glomerular filtration rate at baseline were 66 years and 38.4 mL/min per 1.73 m², respectively. During follow-up (median, 5.9 years), 770 patients received MRAs, 211 died, and 478 started renal replacement therapy. In an inverse probability of weighting-weighted pooled logistic regression model, MRA use was significantly associated with a 28%-lower rate of renal replacement therapy initiation (hazard ratio, 0.72 [95% CI, 0.53-0.98]). The association between MRA use and renal replacement therapy initiation was dose-dependent (P for trend <0.01) and consistent across patient subgroups. The incidence of hyperkalemia (>5.5 mEq/L) was somewhat higher in MRA users but not significant (hazard ratio, 1.14 [95% CI, 0.88-1.48]).

CONCLUSIONS

MRA users showed a better renal prognosis across various chronic kidney disease subgroups in a real-world chronic kidney disease population.

Efficacy and Safety of Esaxerenone in Hypertensive Patients with Diabetic Kidney Disease: A Multicenter, Open-Label, Prospective Study

INTRODUCTION

Clinical data of esaxerenone in hypertensive patients with diabetic kidney disease (DKD) are lacking. We evaluated the efficacy and safety of esaxerenone in patients with DKD and an inadequate response to blood pressure (BP)-lowering treatment.

METHODS

In this multicenter, open-label, prospective study, patients were divided into urinary albumin-to-creatinine ratio subcohorts (UACR < 30, 30 to < 300, and 300 to < 1000 mg/gCr). Esaxerenone was initiated at 1.25 mg/day and followed by incremental dose escalation based on BP and serum potassium level monitoring. The treatment period was 12 weeks. The primary endpoint was change in morning home systolic BP/diastolic BP (SBP/DBP) from baseline to end of treatment (EOT). Secondary endpoints included achievement rate of target BP, change in UACR from baseline, and safety.

RESULTS

In total, 113 patients were enrolled. Morning home SBP/DBP significantly decreased from baseline to EOT in the total population (- 11.6/- 5.2 mmHg, both p < 0.001) and in all UACR subcohorts (all p < 0.001). The target BP achievement rate was 38.5%. Significant reductions in bedtime home and office BPs were also shown in the total population and all UACR subcohorts. UACR significantly improved from baseline to EOT in the total (- 50.9%, p < 0.001) and all UACR subcohorts (all p < 0.001). Incidence of serum potassium elevation as drug-related treatment emergent adverse events was 2.7%. The change from baseline in estimated glomerular filtration rate (eGFR) was - 4.8 mL/min/1.73 m².

CONCLUSION

Esaxerenone demonstrated a BP-lowering effect and improved albuminuria. The effects were consistent regardless of the severity of albuminuria without clinically relevant serum potassium elevation and eGFR reduction.

CLINICAL TRIAL REGISTRATION

jRCTs06119002.

Effects of Spironolactone and Chlorthalidone on Cardiovascular Structure and Function in Chronic Kidney Disease: A Randomized, Open-Label Trial

BACKGROUND AND OBJECTIVES

In a randomized double-blind, placebo-controlled trial, treatment with spironolactone in early-stage CKD reduced left ventricular mass and arterial stiffness compared with placebo. It is not known if these effects were due to BP reduction or specific vascular and myocardial effects of spironolactone.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective, randomized, open-label, blinded end point study conducted in four UK centers (Birmingham, Cambridge, Edinburgh, and London) comparing spironolactone 25 mg to chlorthalidone 25 mg once daily for 40 weeks in 154 participants with nondiabetic stage 2 and 3 CKD (eGFR 30-89 ml/min per 1.73 m²). The primary end point was change in left ventricular mass on cardiac magnetic resonance imaging. Participants were on treatment with an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker and had controlled BP (target ≤130/80 mm Hg).

RESULTS

There was no significant difference in left ventricular mass regression; at week 40, the adjusted mean difference for spironolactone compared with chlorthalidone was -3.8 g (95% confidence interval, -8.1 to 0.5 g, P=0.08). Office and 24-hour ambulatory BPs fell in response to both drugs with no significant differences between treatment. Pulse wave velocity was not significantly different between groups; at week 40, the adjusted mean difference for spironolactone compared with chlorthalidone was 0.04 m/s (-0.4 m/s, 0.5 m/s, P=0.90). Hyperkalemia (defined ≥5.4 mEq/L) occurred more frequently with spironolactone (12 versus two participants, adjusted relative risk was 5.5, 95% confidence interval, 1.4 to 22.1, P=0.02), but there were no patients with severe hyperkalemia (defined ≥6.5 mEq/L). A decline in eGFR >30% occurred in eight participants treated with chlorthalidone compared with two participants with spironolactone (adjusted relative risk was 0.2, 95% confidence interval, 0.05 to 1.1, P=0.07).

CONCLUSIONS

Spironolactone was not superior to chlorthalidone in reducing left ventricular mass, BP, or arterial stiffness in nondiabetic CKD.

Differential restoration of functional hyperemia by antihypertensive drug classes in hypertension-related cerebral small vessel disease

Dementia resulting from small vessel diseases (SVDs) of the brain is an emerging epidemic for which there is no treatment. Hypertension is the major risk factor for SVDs, but how hypertension damages the brain microcirculation is unclear. Here, we show that chronic hypertension in a mouse model progressively disrupts on-demand delivery of blood to metabolically active areas of the brain (functional hyperemia) through diminished activity of the capillary endothelial cell inward-rectifier potassium channel, Kir2.1. Despite similar efficacy in reducing blood pressure, amlodipine, a voltage-dependent calcium-channel blocker, prevented hypertension-related damage to functional hyperemia whereas losartan, an angiotensin II type 1 receptor blocker, did not. We attribute this drug class effect to losartan-induced aldosterone breakthrough, a phenomenon triggered by pharmacological interruption of the renin-angiotensin pathway leading to elevated plasma aldosterone levels. This hypothesis is supported by the finding that combining losartan with the aldosterone receptor antagonist eplerenone prevented the hypertension-related decline in functional hyperemia. Collectively, these data suggest Kir2.1 as a possible therapeutic target in vascular dementia and indicate that concurrent mineralocorticoid aldosterone receptor blockade may aid in protecting against late-life cognitive decline in hypertensive patients treated with angiotensin II type 1 receptor blockers.

Sodium-glucose cotransporter-2 inhibitors and non-steroidal mineralocorticoid receptor antagonists: Ushering in a new era of nephroprotection beyond renin-angiotensin system blockade

The therapeutic options for preventing or slowing the progression of chronic kidney disease (CKD) have been thus far limited. While angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) are, without a doubt, safe and effective drugs, a significant proportion of patients with CKD still progress to end-stage kidney disease. After decades of negative trials, nephrologists have finally found cause for optimism with the introduction of sodium-glucose cotransporter-2 (SGLT2) inhibitors and non-steroidal mineralocorticoid receptor antagonists (MRAs). Recent trials such as EMPA-REG OUTCOME and CREDENCE have provided evidence of the renal benefits of SGLT2 inhibitors, which have now found widespread acceptance as first-line agents for diabetic CKD, in addition to ACEi/ARBs. Considering results from the DAPA-CKD study, it is expected that their use will soon be expanded to other causes of albuminuric CKD as well, although confirmation from further trials, such as the EMPA-KIDNEY study is awaited. Likewise, although the role of mineralocorticoid receptor overactivation in CKD progression has been known for decades, it is only now with the FIDELIO-DKD study that we have evidence of benefits of MRAs on hard renal endpoints, specifically in patients with diabetic CKD. While further research is ongoing, given the evidence of synergism between the three drug classes, it is foreseeable that a combination of two or more of these drugs may soon become the standard of care for CKD, regardless of underlying aetiology. This review describes pathophysiologic mechanisms, current evidence and future perspectives on the use of SGLT2 inhibitors and novel MRAs in CKD.

Aldosterone Negatively Regulates Nrf2 Activity: An Additional Mechanism Contributing to Oxidative Stress and Vascular Dysfunction by Aldosterone

High levels of aldosterone (Aldo) trigger oxidative stress and vascular dysfunction independent of effects on blood pressure. We sought to determine whether Aldo disrupts Nrf2 signaling, the main transcriptional factor involved in antioxidant responses that aggravate cell injury. Thoracic aorta from male C57Bl/6J mice and cultured human endothelial cells (EA.hy926) were stimulated with Aldo (100 nM) in the presence of tiron [reactive oxygen species (ROS) scavenger, eplerenone [mineralocorticoid receptor (MR) antagonist], and L-sulforaphane (SFN; Nrf2 activator). Thoracic aortas were also isolated from mice infused with Aldo (600 μg/kg per day) for 14 days. Aldo decreased endothelium-dependent vasorelaxation and increased ROS generation, effects prevented by tiron and MR blockade. Pharmacological activation of Nrf2 with SFN abrogated Aldo-induced vascular dysfunction and ROS generation. In EA.hy926 cells, Aldo increased ROS generation, which was prevented by eplerenone, tiron, and SFN. At short times, Aldo-induced ROS generation was linked to increased Nrf2 activation. However, after three hours, Aldo decreased the nuclear accumulation of Nrf2. Increased Keap1 protein expression, but not activation of p38 MAPK, was linked to Aldo-induced reduced Nrf2 activity. Arteries from Aldo-infused mice also exhibited decreased nuclear Nrf2 and increased Keap1 expression. Our findings suggest that Aldo reduces vascular Nrf2 transcriptional activity by Keap1-dependent mechanisms, contributing to mineralocorticoid-induced vascular dysfunction.

Clinical efficacy of a benazepril and spironolactone combination in dogs with congestive heart failure due to myxomatous mitral valve disease: The BEnazepril Spironolactone STudy (BESST)

Background

The renin‐angiotensin‐aldosterone system (RAAS), when chronically activated, is harmful and RAAS‐suppressive drugs are beneficial in the treatment of congestive heart failure (CHF). Mineralocorticoid receptor antagonists are widely used in the treatment of CHF in people.

Hypothesis/Objectives

To determine if a mineralocorticoid receptor antagonist (spironolactone) is beneficial and safe in CHF due to myxomatous mitral valve disease (MMVD) of varying severity, we hypothesized that, when combined with furosemide, a combination product (S+BNZ) containing the ACE inhibitor (ACE‐I), benazepril, and spironolactone, would be superior to benazepril alone.

Animals

Five hundred and sixty‐nine client‐owned dogs, with MMVD and CHF (ACVIM Stage C) of ≤10‐days' duration.

Methods

After initial stabilization, dogs were randomized into a positive‐controlled, double‐blind, multicenter trial, to receive furosemide plus S+BNZ or furosemide plus benazepril. The primary outcome variable was the percentage of dogs reaching cardiac endpoint before Day 360. Cardiac endpoint was defined as cardiac death or euthanasia, recurrence of pulmonary edema, necessity for nonauthorized cardiac drug(s) or a furosemide dosage >8 mg/kg/d.

Results

A significantly lower percentage of dogs treated with S+BNZ reached the primary outcome variable by Day 360 (OR = 0.56; 95% CI, 0.32‐0.98; P = .04) and risk of dying or worsening from cardiac causes, was significantly reduced (HR = 0.73; 95% CI = 0.59‐0.89, P = .002) vs benazepril alone. Adverse events, potentially associated with treatment, were rare and equal between groups.

Conclusion and Clinical Importance

The combination of S+BNZ is effective, safe, and superior to benazepril alone, when used with furosemide for the management of mild, moderate or severe CHF caused by MMVD in dogs.

Steroidal and non-steroidal mineralocorticoid receptor antagonists in cardiorenal medicine

This review covers the last 80 years of remarkable progress in the development of mineralocorticoid receptor (MR) antagonists (MRAs) from synthesis of the first mineralocorticoid to trials of nonsteroidal MRAs. The MR is a nuclear receptor expressed in many tissues/cell types including the kidney, heart, immune cells, and fibroblasts. The MR directly affects target gene expression—primarily fluid, electrolyte and haemodynamic homeostasis, and also, but less appreciated, tissue remodelling. Pathophysiological overactivation of the MR leads to inflammation and fibrosis in cardiorenal disease. We discuss the mechanisms of action of nonsteroidal MRAs and how they differ from steroidal MRAs. Nonsteroidal MRAs have demonstrated important differences in their distribution, binding mode to the MR and subsequent gene expression. For example, the novel nonsteroidal MRA finerenone has a balanced distribution between the heart and kidney compared with spironolactone, which is preferentially concentrated in the kidneys. Compared with eplerenone, equinatriuretic doses of finerenone show more potent anti-inflammatory and anti-fibrotic effects on the kidney in rodent models. Overall, nonsteroidal MRAs appear to demonstrate a better benefit–risk ratio than steroidal MRAs, where risk is measured as the propensity for hyperkalaemia. Among patients with Type 2 diabetes, several Phase II studies of finerenone show promising results, supporting benefits on the heart and kidneys. Furthermore, finerenone significantly reduced the combined primary endpoint (chronic kidney disease progression, kidney failure, or kidney death) vs. placebo when added to the standard of care in a large Phase III trial.