Effect of aldosterone breakthrough on albuminuria during treatment with a direct renin inhibitor and combined effect with a mineralocorticoid receptor antagonist

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.

Network pharmacology and molecular docking technology-based predictive study of the active ingredients and potential targets of rhubarb for the treatment of diabetic nephropathy

Diabetic nephropathy (DN) is one of the most serious complications of diabetes and the main cause of end-stage renal failure. Rhubarb is a widely used traditional Chinese herb, and it has exhibited efficacy in reducing proteinuria, lowering blood sugar levels and improving kidney function in patients with DN. However, the exact pharmacological mechanism by rhubarb improves DN remain unclear due to the complexity of its ingredients. Hence, we systematically explored the underlying mechanisms of rhubarb in the treatment of DN. We adopted a network pharmacology approach, focusing on the identification of active ingredients, drug target prediction, gene collection, Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes enrichment. Molecular docking technology was used to verify the binding ability between the main active compounds and central therapeutic targets, and screen out the core active ingredients in rhubarb for the treatment of DN. Finally, molecular dynamics simulation was performed for the optimal core protein-ligand obtained by molecular docking using GROMACS software. The network analysis identified 16 active compounds in rhubarb that were linked to 37 possible therapeutic targets related to DN. Through protein-protein interaction analysis, TP53, CASP8, CASP3, MYC, JUN and PTGS2 were identified as the key therapeutic targets. By validation of molecular docking, finding that the central therapeutic targets have good affinities with the main active compounds of rhubarb, and rhein, beta-sitosterol and aloe-emodin were identified as the core active ingredients in rhubarb for the treatment of DN. Results from molecular dynamics simulations showed that TP53 and aloe-emodin bound very stably with a binding free energy of - 26.98 kcal/mol between the two. The results of the gene enrichment analysis revealed that the PI3K-Akt signalling pathway, p53 signalling pathway, AGE-RAGE signalling pathway and MAPK signalling pathway might be the key pathways for the treatment of DN, and these pathways were involved in podocyte apoptosis, glomerular mesangial cell proliferation, inflammation and renal fibrosis. Based on the network pharmacology approach and molecular docking technology, we successfully predicted the active compounds and their respective targets. In addition, we illustrated the molecular mechanisms that mediate the therapeutic effects of rhubarb against DN. These findings provided an important scientific basis for further research of the mechanism of rhubarb in the treatment of DN.

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.

Effects of mineralocorticoid receptor antagonists on sex hormones and body composition in patients with primary aldosteronism

Mineralocorticoid receptor antagonists are frequently used for the treatment of primary aldosteronism. Steroidal mineralocorticoid receptor antagonists may have antagonistic actions on androgen receptors, agonistic actions on progesterone receptors, and antagonistic actions on mineralocorticoid receptors. Because anti-androgen effects may cause body fat accumulation and skeletal muscle atrophy, there are concerns that this drug may have adverse effects on body composition. Therefore, in this randomized prospective study, we compared the adverse effects of spironolactone, a steroidal mineralocorticoid receptor antagonist, and esaxerenone, a nonsteroidal mineralocorticoid receptor antagonist, on sex hormone levels and body composition in patients with primary aldosteronism without severe renal dysfunction. The serum concentration of free testosterone was significantly higher in the spironolactone group than in the esaxerenone group in both males and females. However, the levels of estradiol, progesterone, luteinizing hormone, and follicle stimulating hormone did not significantly increase. Changes in body fat percentage and muscle mass rate were not significantly different between the two groups. No patient showed a serum potassium level ≥6.0 mEq/L; however, serum potassium levels were significantly higher in the spironolactone group than in the esaxerenone group. These data indicate that spironolactone may have antagonistic effects on androgen receptors. Esaxerenone did not show any apparent adverse effects, suggesting that it can be safely used in patients with primary aldosteronism.

A systematic review and meta-analysis of effects of spironolactone on blood pressure, glucose, lipids, renal function, fibrosis and inflammation in patients with hypertension and diabetes

PURPOSE

Hypertension commonly co-exists with diabetes mellitus (DM), and both are closely related to adverse health outcomes. The activation of aldosterone and mineralocorticoid receptor (MR) may play important roles in this process. Therefore, we aim to evaluate the efficacy of MR antagonists on cardiovascular risk factors, including blood pressure (BP), glucose, lipids, renal function, fibrosis and inflammatory and its safety in patients with both hypertension and DM.

METHODS

We searched PubMed, Embase, Web of Science and Cochrane databases for clinical trials published until December 31, 2019. Studies comparing the effect of spironolactone to placebo in patients with hypertension and DM were included. Mean difference with 95% confidence intervals was used to report outcomes.

RESULTS

Eleven randomised placebo-controlled trials with 640 participants were finally included with mean follow-up of 5 months. Compared to placebo, spironolactone significantly reduced office systolic (-6.57, 95%CI: -9.21, -3.93) and diastolic BP (-2.63, 95%CI: -4.25, -1.02) as well as ambulatory BP; increased glycosylated haemoglobin by 0.3 but no clear effect on fasting glucose. Spironolactone induced a significantly reduction of urinary albumin but increased serum creatinine (7.60, 95%CI: 4.94, 10.27) and decreased glomerular filtration rate (-4.28, 95%CI: -6.38, -2.18). Markers of fibrosis and inflammation, including NIIINP, PICP, hs-CRP and TNF-α were also decreased after spironolactone therapy. For lipid metabolism, there was no significant difference between groups. Spironolactone mildly increased serum potassium (0.30, 95%CI: 0.23, 0.37). 2.5% subjects treated with spironolactone experienced mild to moderate hyperkalaemia and received medication or dietary advice and another 1.6% developed severe hyperkalaemia and withdrawn from the studies.

CONCLUSION

Spironolactone reduced BP and urinary albumin, improve fibrosis and inflammation, whereas slightly increases the glycosylated haemoglobin and serum creatinine in patients with hypertension and diabetes. Long-term RCTs to assess the effects of spironolactone on cardiovascular events in this population are warranted.

Effect of spironolactone on cardiovascular morbidity and mortality in patients with hypertension and glucose metabolism disorders (ESCAM): a study protocol for a pragmatic randomised controlled trial

INTRODUCTION

Hypertension combined with diabetes and hypokalemia is more likely to develop hyperaldosteronism and is at higher risk of cardiovascular events. There is evidence that activation of aldosterone and mineralocorticoid receptors may play a significant role in the occurrence of cardiovascular events in patients with hypertension and diabetes. Clinical studies have demonstrated that spironolactone can reduce the incidence of cardiovascular events in patients with chronic kidney diseases or severe heart failure. However, the effect of spironolactone on cardiovascular risk in patients with hypertension and glucose metabolism disorders (GMD) and low potassium has been scarcely studied. Therefore, this study aims to evaluate whether add-on spironolactone (conventional antihypertensive drugs alone vs conventional antihypertensive drugs+spironolactone) can reduce the morbidity and mortality of cardiovascular events in this population.

METHODS AND ANALYSIS

In this multicentre, randomised, parallel-controlled study, a total of 7140 hypertensive patients aged 45-75 years with GMD and low potassium will be randomised in a 1:1 manner to the control or the spironolactone group (20 mg/day or with a maximum dose of 40 mg). The primary objective is to estimate the difference in the HR of composite cardiovascular events between the two groups. We will also assess the effects of spironolactone on individual cardiovascular events and the progression of diabetes and renal dysfunction.

ETHICS AND DISSEMINATION

This protocol was approved by the Independent Ethics Committee of People's Hospital of Xinjiang Uygur Autonomous Region (no. 2020020618). The results will be disseminated in peer-reviewed journals and at scientific conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2000028909.

Impact of mineralocorticoid receptor blockade with direct renin inhibition in angiotensin II-dependent hypertensive mice

It has been suggested that aldosterone breakthrough during treatment with a type 1 angiotensin II receptor (AT1R) blocker (ARB) may be an important risk factor for the progression of renal and cardiovascular disease. We examined whether the direct renin inhibitor, aliskiren caused aldosterone breakthrough in angiotensin II (Ang II)-dependent hypertensive mice. The effect of combination therapy with aliskiren and eplerenone was compared with that of therapy using renin-angiotensin system (RAS) blockade. Tsukuba hypertensive mice were treated for 12 weeks with aliskiren (30 mg/kg/day, i.p), candesartan (5 mg/kg/day, p.o), eplerenone (100 mg/kg/day, p.o) aliskiren and candesartan, aliskiren and eplerenone or candesartan and eplerenone. Blood pressure, urinary aldosterone and angiotensinogen (AGTN) excretion; plasma endothelin-1 concentration; kidney weight; urinary albumin excretion (UAE); glomerular injury; and renal messenger RNA (mRNA) levels for transforming growth factor (TGF)-β1, plasminogen activator inhibitor (PAI)-1, angiotensin-converting enzyme (ACE) and AT1R were measured. Combination therapy with aliskiren and candesartan caused a further decrease in blood pressure (p < 0.05) compared with either agent alone. Urinary aldosterone excretion was decreased significantly by 4 weeks of treatment with aliskiren or candesartan (p < 0.05). However, it was increased again by treatment with candesartan or aliskiren for 12 weeks. Combination therapy with aliskiren and eplerenone significantly decreased UAE, the glomerulosclerosis index, and PAI-1 and TGF-β1 mRNA levels compared with all other therapies (p < 0.05). Treatment with aliskiren decreased urinary aldosterone excretion at 4 weeks and increased it at 12 weeks. Combination therapy with a direct renin inhibitor and a mineralocorticoid receptor blocker may be effective for the prevention of renal injury in Ang II-dependent hypertension.

The renin-angiotensin-aldosterone system and its suppression

Chronic activation of the renin-angiotensin-aldosterone system (RAAS) promotes and perpetuates the syndromes of congestive heart failure, systemic hypertension, and chronic kidney disease. Excessive circulating and tissue angiotensin II (AngII) and aldosterone levels lead to a pro-fibrotic, -inflammatory, and -hypertrophic milieu that causes remodeling and dysfunction in cardiovascular and renal tissues. Understanding of the role of the RAAS in this abnormal pathologic remodeling has grown over the past few decades and numerous medical therapies aimed at suppressing the RAAS have been developed. Despite this, morbidity from these diseases remains high. Continued investigation into the complexities of the RAAS should help clinicians modulate (suppress or enhance) components of this system and improve quality of life and survival. This review focuses on updates in our understanding of the RAAS and the pathophysiology of AngII and aldosterone excess, reviewing what is known about its suppression in cardiovascular and renal diseases, especially in the cat and dog.

Role of Aldosterone in Renal Fibrosis

Aldosterone is a mineralocorticoid hormone, as its main renal effect has been considered as electrolyte and water homeostasis in the distal tubule, thus maintaining blood pressure and extracellular fluid homeostasis through the activation of mineralocorticoid receptor (MR) in epithelial cells. However, over the past decade, numerous studies have documented the significant role of aldosterone in the progression of chronic kidney disease (CKD) which has become a subject of interest. It is being studied that aldosterone can affect cardiovascular and renal system, thereby contributing to tissue inflammation, injury, glomerulosclerosis, and interstitial fibrosis. Aldosterone acts on renal vessels, renal cells (glomerular mesangial cells, podocytes, vascular smooth muscle cells, tubular epithelial cells, and interstitial fibroblasts), and infiltrating inflammatory cells, inducing reactive oxygen species (ROS) production, upregulated epithelial growth factor receptor (EGFR), and type 1 angiotensin (AT1) receptor expressions, and activating nuclear factor kappa B (NF-κB), activator protein-1 (AP-1), and EGFR to further promote cell proliferation, apoptosis, and proliferation. Phenotypic transformation of epithelial cells stimulates the expression of transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), osteopontin (OPN), and plasminogen activator inhibitor-1 (PAI-1), eventually leading to renal fibrosis. MR antagonisms are related to inhibition of aldosterone-mediated pro-inflammatory and pro-fibrotic effect. In this review, we will summarize the important role of aldosterone in the pathogenesis of renal injury and fibrosis, emphasizing on its multiple underlying mechanisms and advances in aldosterone research along with the potential therapeutics for targeting MR in a renal fibrosis.

Aldosterone and the Mineralocorticoid Receptor: Risk Factors for Cardiometabolic Disorders

Preclinical studies have convincingly demonstrated a role for the mineralocorticoid receptor (MR) in adipose tissue physiology. These studies show that increased MR activation causes adipocyte dysfunction leading to decreased production of insulin-sensitizing products and increased production of inflammatory factors, creating an environment conducive to metabolic and cardiovascular disease. Accumulating data also suggest that MR activation may be an important link between obesity and metabolic syndrome. Moreover, MR activation may mediate the pathogenic consequences of metabolic syndrome. Recent attempts at reversing cardiometabolic damage in patients with type 2 diabetes using MR antagonists have shown promising results. MR antagonists are already used to treat heart failure where their use decreases mortality and morbidity over and above the use of traditional therapies alone. However, more data are needed to establish the benefits of MR antagonists in diabetes, obesity, and metabolic syndrome.

The necessity and effectiveness of mineralocorticoid receptor antagonist in the treatment of diabetic nephropathy

Diabetes mellitus is a major cause of chronic kidney disease (CKD), and diabetic nephropathy is the most common primary disease necessitating dialysis treatment in the world including Japan. Major guidelines for treatment of hypertension in Japan, the United States and Europe recommend the use of angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers, which suppress the renin-angiotensin system (RAS), as the antihypertensive drugs of first choice in patients with coexisting diabetes. However, even with the administration of RAS inhibitors, failure to achieve adequate anti-albuminuric, renoprotective effects and a reduction in cardiovascular events has also been reported. Inadequate blockade of aldosterone may be one of the reasons why long-term administration of RAS inhibitors may not be sufficiently effective in patients with diabetic nephropathy. This review focuses on treatment in diabetic nephropathy and discusses the significance of aldosterone blockade. In pre-nephropathy without overt nephropathy, a mineralocorticoid receptor antagonist can be used to enhance the blood pressure-lowering effects of RAS inhibitors, improve insulin resistance and prevent clinical progression of nephropathy. In CKD categories A2 and A3, the addition of a mineralocorticoid receptor antagonist to an RAS inhibitor can help to maintain 'long-term' antiproteinuric and anti-albuminuric effects. However, in category G3a and higher, sufficient attention must be paid to hyperkalemia. Mineralocorticoid receptor antagonists are not currently recommended as standard treatment in diabetic nephropathy. However, many studies have shown promise of better renoprotective effects if mineralocorticoid receptor antagonists are appropriately used.