Mineralocorticoid antagonists in chronic kidney disease:

Renoprotective Effects of Mineralocorticoid Receptor Antagonists Against Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a growing epidemic worldwide and a leading cause of end-stage kidney disease. Mineralocorticoid receptor (MR) blockade using Finerenone is a recently approved therapeutic approach to slow down the progression of DKD in patients with type 2 diabetes in addition to other therapies such as angiotensin-II converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), sodium-glucose co-transporter 2 (SGLT2) inhibitors, and glucagon-like peptide 1 (GLP-1) analogs. This review elaborates on the pathophysiologic pathways activated by aldosterone (the human mineralocorticoid) in DKD, the pharmacology of three different generations of mineralocorticoid receptor antagonists (MRAs), specifically, spironolactone, eplerenone, and finerenone, and the mechanisms by which these MRAs elicit their protective effects on the kidney under diabetic settings.

How to Choose the Right Treatment for Membranous Nephropathy

Membranous nephropathy is an autoimmune disease affecting the glomeruli and is one of the most common causes of nephrotic syndrome. In the absence of any therapy, 35% of patients develop end-stage renal disease. The discovery of autoantibodies such as phospholipase A2 receptor 1, antithrombospondin and neural epidermal growth factor-like 1 protein has greatly helped us to understand the pathogenesis and enable the diagnosis of this disease and to guide its treatment. Depending on the complications of nephrotic syndrome, patients with this disease receive supportive treatment with diuretics, ACE inhibitors or angiotensin-receptor blockers, lipid-lowering agents and anticoagulants. After assessing the risk of progression of end-stage renal disease, patients receive immunosuppressive therapy with various drugs such as cyclophosphamide, steroids, calcineurin inhibitors or rituximab. Since immunosuppressive drugs can cause life-threatening side effects and up to 30% of patients do not respond to therapy, new therapeutic approaches with drugs such as adrenocorticotropic hormone, belimumab, anti-plasma cell antibodies or complement-guided drugs are currently being tested. However, special attention needs to be paid to the choice of therapy in secondary forms or in specific clinical contexts such as membranous disease in children, pregnant women and patients undergoing kidney transplantation.

Diagnosis and treatment of lupus nephritis: a summary of the Consensus Document of the Spanish Group for the Study of Glomerular Diseases (GLOSEN)

Lupus nephritis (LN) is the most frequent serious manifestation of patients with systemic lupus erythematosus (SLE). Up to 60% of SLE patients develop LN, which has a significant impact on their quality of life and prognosis. Recent advances have improved the diagnostic approach to LN, and new drugs that block specific pathways and kidney damage progression have been developed. Several randomized and well-powered clinical trials have confirmed the efficacy of these agents in terms of proteinuria remission and preservation of kidney function in the medium and long term, with an acceptable safety profile and good tolerance. The combination of different therapies allows for reduction of the dose and duration of corticosteroids and other potentially toxic therapies and leads to an increase in the number of patients achieving complete remission of the disease. This consensus document carried out by the Spanish Group for the Study of Glomerular Diseases (GLOSEN) provides practical and updated recommendations, based on the best available evidence and clinical expertise of participating nephrologists.

Consensus document of the Spanish Group for the Study of the Glomerular Diseases (GLOSEN) for the diagnosis and treatment of lupus nephritis

A significant number of patients with systemic lupus erythematosus (between 20% and 60% according to different reported series) develop lupus nephritis in the course of its evolution, which directly influences their quality of life and vital prognosis. In recent years, the greater knowledge about the pathogenesis of systemic lupus and lupus nephritis has allowed relevant advances in the diagnostic approach and treatment of these patients, achieving the development of drugs specifically aimed at blocking key pathogenic pathways of the disease. Encouragingly, these immunomodulatory agents have shown in well-powered, randomized clinical trials good clinical efficacy in the medium-term, defined as proteinuria remission and preservation of kidney function, with an acceptable safety profile and good patient tolerability. All this has made it possible to reduce the use of corticosteroids and other potentially more toxic therapies, as well as to increase the use of combined therapies. The present consensus document carried out by the Glomerular Diseases Working Group of the Spanish Society of Nephrology (GLOSEN), collects in a practical and summarized, but rigorous way, the best currently available evidence about the diagnosis, treatment, and follow-up of lupus nephritis patients, including cases of special situations, with the main objective of providing updated information and well-founded clinical recommendations to treating physicians, to improve the diagnostic and therapeutic approach to our patients.

The role of aldosterone in the pathogenesis of diabetic retinopathy

Aldosterone, as a mineralocorticoid of adrenal origin, has effects that are not limited to the urinary tract. As an important regulator in Vasoactive hormone pathways, aldosterone may play an effect in the pathogenesis of diabetic retinopathy (DR) through the regulation of oxidative stress, vascular regulation, and inflammatory mechanisms. This implies that mineralocorticoids, including aldosterone, have great potential and value for the diagnosis and treatment of DR. Because early studies did not focus on the intrinsic association between mineralocorticoids and DR, targeted research is still in its infancy and there are still many obstacles to its application in the clinical setting. Recent studies have improved the understanding of the effects of aldosterone on DR, and we review them with the aim of exploring possible mechanisms for the treatment and prevention of DR.

[Current aspects of heart-kidney interactions : Summary of important clinical studies from 2020]

Patients with chronic kidney diseases show an increased cardiovascular morbidity and mortality. Last year a number of important studies on heart-kidney interaction were published, which are summarized and discussed in this article. In the DAPA-CKD study and the SCORED study two different sodium-glucose linked transporter 2 (SGLT2) inhibitors (dapagliflozin and sotagliflozin) were found to improve the prognosis of patients with chronic kidney diseases with and without diabetes. The results of the randomized study on the new mineralocorticoid receptor antagonist finerenon (FIDELIO-DKD) also provided a very promising novel treatment approach for patients with diabetic nephropathy. The published data of the ISCHEMIA-CKD study in patients with coronary heart disease and investigations on the influence of transcatheter aortic valve implantation (TAVI) on renal function as well as another study on acute kidney failure after MitraClip® (Abbott, Chicago, IL, USA) implantation provide important indications for future treatment recommendations. The optimal timing of the initiation of kidney replacement therapy in patients with acute kidney damage in intensive care medicine was investigated in two randomized studies, which are correspondingly discussed.

Mineralocorticoid Receptor Antagonists-Evidence for Kidney Protection, Trials With Novel Agents

The area of aldosterone blockade has exploded in the last decade with the development of four new compounds of a different class referred to as nonsteroidal mineralocorticoid receptor antagonists (MRAs). Their chemistry and clinical charatcteristics are distinctly different from their steroidal cousins. Apart from blocking aldosterone activity, albeit in a different way than the steroidal MRAs, they have much less blood pressure (BP) effects and are better tolerated. The spectrum of nonsteroidal MRAs includes one agent with significant BP reduction, KBP-5074, to agents with minimal BP effects yet have demonstrated significant cardiorenal risk reduction in diabetic kidney disease, finerenone. The paper reviews the development and pharmacology of these different agents and tries to provide a perspective as to their place in the spectrum of aldosterone excess disorders.

Non-steroidal mineralocorticoid antagonists: Prospects for renoprotection in diabetic kidney disease

Diabetic kidney disease (DKD) is the major cause of kidney failure in the world and the combination of DKD and diabetes mellitus contributes to an additive incidence of worsening cardiovascular mortality rates. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) remain the mainstay of therapy and have reduced kidney function decline in DKD from 8 to 10 to ~4 mL/min/y. Sodium-glucose co-transporter-2 (SGLT2) inhibitors, in the presence of ACE inhibitors or ARB agents, further slowdown DKD progression by an additional 58% to 1.8 mL/min/y. Moreover, SGLT2 inhibitors reduce heart failure risk. However, the normal rate of kidney function decline in humans is between 0.7 and 0.9 mL/min/y, hence, there is still room for improvement. Mineralocorticoid receptor antagonists (MRAs) already have a track record of benefit in heart failure risk reduction, and efficacy in reducing albuminuria and treating resistant hypertension; however hyperkalaemia and other adverse effects preclude their routine use in DKD. Novel non-steroidal MRAs offer a reduced risk of hyperkalaemia, and yet have many benefits that they share with their steroidal cousins. This paper reviews the data for both steroidal and non-steroidal MRAs in DKD and presents some data from soon-to-be-completed ongoing renal and cardiovascular outcome trials in DKD.

Design and Baseline Characteristics of the Finerenone in Reducing Cardiovascular Mortality and Morbidity in Diabetic Kidney Disease Trial

BACKGROUND

Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials.

PATIENTS AND METHODS

The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate ≥25 mL/min/1.73 m2 and albuminuria (urinary albumin-to-creatinine ratio ≥30 to ≤5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level α = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure.

CONCLUSIONS

FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen.

TRIAL REGISTRATION

EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049.

Design and Baseline Characteristics of the Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease Trial

BACKGROUND

Among diabetics, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality, and progression of their underlying disease. Finerenone is a novel, non-steroidal, selective mineralocorticoid-receptor antagonist which has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD), while revealing only a low risk of hyperkalemia. However, the effect of finerenone on renal and CV outcomes has not been investigated in long-term trials yet.

METHODS

The Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease -(FIDELIO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important renal and CV outcomes in T2D patients with CKD. FIDELIO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 5.5 years. FIDELIO-DKD randomized 5,734 patients with an estimated glomerular filtration rate (eGFR) ≥25-<75 mL/min/1.73 m2 and albuminuria (urinary albumin-to-creatinine ratio ≥30-≤5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of primary outcome (overall two-sided significance level α = 0.05), the composite of time to first occurrence of kidney failure, a sustained decrease of eGFR ≥40% from baseline over at least 4 weeks, or renal death.

CONCLUSION

FIDELIO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of renal and CV events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen.

Chronic kidney disease progression in patients with resistant hypertension subject to 2 therapeutic strategies: Intensification with loop diuretics vs aldosterone antagonists

INTRODUCTION

Actualy, there are few data about glomerular filtration rate (eGFR) drop in patients with resistant hypertension and how diferent therapies can modify chronic kidney disease progression (CKD).

OBJECTIVE

To evaluate CKD progression in patients with resistant hypertension undergoing 2diferent therapies: treatment with spironolactone or furosemide.

METHODS

We included 30 patients (21M, 9W) with a mean age of 66.3±9.1 years, eGFR 55.8±16.5ml/min/1.73 m², SBP 162.8±8.2 and DBP 90.2±6.2mmHg: 15 patients received spironolactone and 15 furosemide and we followed up them a median of 32 months (28-41).

RESULTS

The mean annual eGFR decrease was -2.8±5.4ml/min/1.73 m². In spironolactone group was -2.1±4.8ml/min/1.73 m² and in furosemide group was -3.2±5.6ml/min/1.73 m², P<0.01. In patients received spironolactone, SBP decreased 23±9mmHg and in furosemide group decreased 16±3mmHg, P<.01. DBP decreased 10±8mmHg and 6±2mmHg, respectively (P<.01). Treatment with spironolactone reduced albuminuria from a serum albumin/creatine ratio of 210 (121-385) mg/g to 65 (45-120) mg/g at the end of follow-up, P<.01. There were no significant changes in the albumin/creatinine ratio in the furosemide group. The slower drop in kidney function was associated with lower SBP (P=.04), higher GFR (P=.01), lower albuminuria (P=.01), not diabetes mellitus (P=.01) and treatment with spironolactone (P=.02). Treatment with spironolactone (OR 2.13, IC 1.89-2.29) and lower albuminuria (OR 0.98, CI 0.97-0.99) maintain their independent predictive power in a multivariate model.

CONCLUSION

Treatment with spironolactone is more effective reducing BP and albuminuria in patients with resistant hypertension compared with furosemide and it is associated with a slower progression of CKD in the long term follow up.

Spironolactone alleviates diabetic nephropathy through promoting autophagy in podocytes

PURPOSE

Podocytes are terminally differentiated cells lining the Bowman's capsule. Podocytes are critical for the proper glomerular filtration barrier function. At the same time, autophagy is crucial for maintaining podocyte homeostasis and insufficient autophagy could cause podocyte loss and proteinuria that is commonly observed in diabetic nephropathy (DN).

METHODS

In this study, we investigated the role of spironolactone in podocyte loss and autophagy. DN model was established in male Sprague-Dawley rats using high-fat diet and low-dose streptozotocin. The impact of spironolactone on metabolic and biochemical parameters were tested by automatic biochemical analyzer. The angiotensin converting enzyme 1 and 2 (ACE1 and ACE2) and aldosterone were examined by ELISA. We examined the kidney histology and autophagy in podocytes by histochemical staining and electron microscopy. Podocyte loss and autophagy were analyzed by anti-NPHS2 and anti-WT1 as well as anti-Beclin1 and anti-LC3B, respectively.

RESULTS

Spironolacton decreased the urinary albumin excretion, lipids and fasting glucose levels, and alleviated kidney damage. Further, spironolactone increased the expression of the podocyte-specific markers WT1 and NPHS2, as well as the autophagic markers Beclin1 and LC3B (P < 0.05). Additionally, spironolactone partially blocked the rennin angiotensin aldosterone system (RAAS) by regulating the ACE1, ACE2 and aldosterone levels.

CONCLUSIONS

In conclusion, spironolactone promoted autophagy in podocytes and further alleviated DN through partially blocking the RAAS.

The dilemma of dual renin-angiotensin system blockade in chronic kidney disease: why beneficial in animal experiments but not in the clinic?

Drugs interfering with the renin-angiotensin-aldosterone system (RAAS) improved the prognosis in patients with hypertension, heart failure, diabetes and chronic kidney disease. However, combining different drugs brought no further benefit while increasing the risk of hyperkalemia, hypotension and acute renal failure. This was so with combining angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptors type 1 antagonists (ARB). Dissimilarly, in animal disease models this dual therapy proved clearly superior to single drug treatment and became the optimal standard regime for comparison with other treatments. This review analyzes the causes of the discrepancy of effects of the dual therapy between animal experiments versus clinical studies, and is focused on the outcomes in chronic kidney disease. Discussed is the role of species differences in RAAS, of the variability of the disease features in humans versus relative stability in animals, of the genetic uniformity in the animals but not in humans, and of the biased publication habits of experimental versus clinical studies. We attempt to understand the causes and reconcile the discordant findings and suggest to what extent dual RAAS inhibition should be continued in animal experiments and why its application in the clinics should be limited to strictly selected groups of patients.