Aldosterone breakthrough during angiotensin receptor blocker use: more questions than answers?

Potential of Modulating Aldosterone Signaling and Mineralocorticoid Receptor with microRNAs to Attenuate Diabetic Kidney Disease

Diabetic Kidney Disease (DKD) is a significant complication of diabetes and primary cause of end-stage renal disease globally. The exact mechanisms underlying DKD remain poorly understood, but multiple factors, including the renin-angiotensin-aldosterone system (RAAS), play a key role in its progression. Aldosterone, a mineralocorticoid steroid hormone, is one of the key components of RAAS and a potential mediator of renal damage and inflammation in DKD. miRNAs, small noncoding RNA molecules, have attracted interest due to their regulatory roles in numerous biological processes. These processes include aldosterone signaling and mineralocorticoid receptor (MR) expression. Numerous miRNAs have been recognized as crucial regulators of aldosterone signaling and MR expression. These miRNAs affect different aspects of the RAAS pathway and subsequent molecular processes, which impact sodium balance, ion transport, and fibrosis regulation. This review investigates the regulatory roles of particular miRNAs in modulating aldosterone signaling and MR activation, focusing on their impact on kidney injury, inflammation, and fibrosis. Understanding the complex interaction between miRNAs and the RAAS could lead to a new strategy to target aldosterone signaling and MR activation using miRNAs. This highlights the potential of miRNA-based interventions for DKD, with the aim of enhancing kidney outcomes in individuals with diabetes.

The Effect of Aldosterone on Cardiorenal and Metabolic Systems

Aldosterone, a vital hormone of the human body, has various pathophysiological roles. The excess of aldosterone, also known as primary aldosteronism, is the most common secondary cause of hypertension. Primary aldosteronism is associated with an increased risk of cardiovascular disease and kidney dysfunction compared to essential hypertension. Excess aldosterone can lead to harmful metabolic and other pathophysiological alterations, as well as cause inflammatory, oxidative, and fibrotic effects in the heart, kidney, and blood vessels. These alterations can result in coronary artery disease, including ischemia and myocardial infarction, left ventricular hypertrophy, heart failure, arterial fibrillation, intracarotid intima thickening, cerebrovascular disease, and chronic kidney disease. Thus, aldosterone affects several tissues, especially in the cardiovascular system, and the metabolic and pathophysiological alterations are related to severe diseases. Therefore, understanding the effects of aldosterone on the body is important for health maintenance in hypertensive patients. In this review, we focus on currently available evidence regarding the role of aldosterone in alterations of the cardiovascular and renal systems. We also describe the risk of cardiovascular events and renal dysfunction in hyperaldosteronism.

Cardiovascular and kidney outcomes of spironolactone or eplerenone in combination with ACEI/ARBs in patients with diabetic kidney disease

BACKGROUND

Mineralocorticoid receptor antagonist (MRA) when combined with either angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) may provide additional benefits of cardiovascular and kidney disease risk reduction in patients with diabetic kidney disease (DKD) and hypertension. We evaluated the effectiveness of combination therapy (MRAs, either spironolactone or eplerenone, plus ACEI/ARB) compared with monotherapy (ACEI/ARB only) in patients with DKD and hypertension.

METHODS

Retrospective cohort study was performed in patients (age ≥ 18 years) with hypertension, diabetes, and albuminuria between 2008 and 2018 within an integrated health system. MRA with ACEI/ARB compared to ACEI/ARB alone was evaluated on composite of cardiovascular events, progression to end-stage kidney disease, or all-cause mortality. Hyperkalemia was compared as a safety outcome.

RESULTS

We identified 1282 patients who received MRAs with ACEI/ARBs and 5484 patients who received ACEI/ARBs alone. Median exposure time for combination therapy was 126 days. The rates per 100 person-years of cardiovascular, kidney, or all-cause mortality outcomes were 12.2 and 9.2 for combination therapy and monotherapy, respectively (hazard ratios = 1.24, 95% Confidence Interval (CI):0.94, 1.63). Patients receiving combination therapy had greater reduction in urine albumin-to-creatinine ratio compared with monotherapy (Mean reduction: 823 and 585 mg/g; p < 0.001, respectively). Hyperkalemia was more frequent in combination therapy versus monotherapy (22.3 vs. 10.9 per 100 person-years for combination and monotherapy, respectively; hazard ratios = 1.78, 95%CI: 1.42, 2.24).

CONCLUSIONS

Among patients with DKD and hypertension, the short-term use of MRAs, either spironolactone or eplerenone, in combination with ACEI/ARBs, was not associated with lower risk of cardiovascular or kidney outcomes compared with ACEI/ARB monotherapy. The risk of hyperkalemia and the short duration of combination therapy may suggest a real-world clinical challenge for MRA with ACEI/ARB combination therapy.

Effects of antihypertensive medication and high-intensity interval training in hypertensive metabolic syndrome individuals

Pharmacological and non-pharmacological therapies are simultaneously prescribed when treating hypertensive individuals with elevated cardiovascular risk (ie, metabolic syndrome individuals). However, it is unknown if the interactions between antihypertensive medication (AHM) and lifestyle interventions (ie, exercise training) may result in a better ambulatory blood pressure (ABP) control. To test this hypothesis, 36 hypertensive individuals with metabolic syndrome (MetS) under long-term prescription with AHM targeting the renin-angiotensin-aldosterone system (RAAS) were recruited. Before and after 4 months of high-intensity interval training (HIIT), participants completed two trials in a double-blind, randomized order: (a) placebo trial consisting of AHM withdrawal for 3 days and (b) AHM trial where individuals held their habitual dose of AHM. In each trial, 24-h mean arterial pressure (MAP) was monitored and considered the primary study outcome. Secondary outcomes included plasma renin activity (PRA) and aldosterone concentration to confirm withdrawal effects on RAAS, along with the analysis of urine albumin-to-creatinine ratio (UACR) to assess kidney function. The results showed main effects from AHM and HIIT reducing 24-h MAP (-5.7 mmHg, p < 0.001 and -2.3 mmHg, p = 0.007, respectively). However, there was not interaction between AHM and HIIT on 24-h MAP (p = 0.240). There was a main effect of AHM increasing PRA (p < 0.001) but no effect on plasma aldosterone concentration (p = 0.368). HIIT did not significantly improve RAAS hormones or the UACR. In conclusion, AHM and HIIT have independent and additive effects in lowering ABP. These findings support the combination of habitual AHM with exercise training with the goal to reduce ABP in hypertensive MetS individuals.

Prognostic impact of additional mineralocorticoid receptor antagonists in octogenarian heart failure patients

AIMS

Guideline-directed medical therapy (GDMT) including beta-blockers and renin-angiotensin system inhibitors is shown to reduce mortality risk in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF). However, there is little evidence about the efficacy of additional administration of mineralocorticoid receptor antagonists (MRAs) with GDMT in patients ≥80 years presenting with HF. We aimed to investigate the prognostic impact of GDMT with MRA in relation to the age of patients with HF.

METHODS AND RESULTS

This observational study included patients admitted for HF with reduced LVEF who were discharged alive; among them, 224 patients were ≥80 years, and 661 patients were <80 years. Both populations were divided into three groups depending on whether they received GDMT with or without MRA or single/no GDMT drugs (GDMT+MRA+, GDMT+MRA-, or non-GDMT, respectively). The primary endpoint was all-cause mortality. In patients ≥80 years, all-cause mortality was the lowest in the GDMT+MRA+ group (log-rank trend, P = 0.034), and no significant differences were observed between the GDMT+MRA- and non-GDMT groups. Multivariate Cox regression analysis revealed that GDMT+MRA+ was superior to GDMT+MRA-, even after adjusting for parameters at discharge (hazard ratio: 0.32, 95% confidence interval: 0.11-0.99). In patients <80 years, GDMT reduced all-cause mortality; however, additional MRA was not associated with an improved outcome.

CONCLUSIONS

The results of this study suggest that additional MRA to GDMT at discharge is one of the therapeutic options for elderly HF patients with reduced LVEF. This finding is not well documented in previous clinical trials.

miR-196b-5p-enriched extracellular vesicles from tubular epithelial cells mediated aldosterone-induced renal fibrosis in mice with diabetes

INTRODUCTION

Aldosterone is a mediator of progressive renal disease, but the mechanisms for aldosterone-mediated renal impairment in mice with diabetes are not fully defined.

METHODS

Aldosterone and/or mineralocorticoid receptor antagonist eplerenone were used to treat the db/db mice with diabetes. Proximal tubule epithelial cells (PTECs) and fibroblasts were cultured. Blood and kidney samples from patients with diabetes with or without diabetic kidney disease (DKD) were used to verify the findings from animals and cultured cells.

RESULTS

We found that aldosterone promoted proteinuria and tubulointerstitial extracellular matrix (ECM) accumulation in db/db mice with diabetes while eplerenone mitigated the adverse effect of aldosterone. However, coculture of PTECs and fibroblasts found that when PTECs-derived extracellular vesicles (EVs) were taken up by fibroblasts, ECM production increased remarkably. Moreover, C57BL/6 mice injected with EVs from renal cortex of aldosterone-treated db/db mice showed increased ECM accumulation. Function of the ingredients of PTECs-derived EVs were analyzed, and RNAs were identified to be responsible for the EVs-induced fibroblast dysfunction. Furthermore, microRNA (miRNA) array analysis revealed that miR-196b-5p was the most remarkably increased miRNA in PTECs-derived EVs with aldosterone stimulation. Overexpression of miR-196b-5p in fibroblasts increased ECM production, accompanied by inhibition of the SOCS2 expression and enhanced STAT3 phosphorylation. In addition, plasma levels of miR-196b-5p was higher in patients with DKD as compared with patients without DKD and miR-196b-5p levels positively correlated with the albuminuria concentration. In kidney specimens from patients with diabetes, expression of miR-196b-5p, located mainly in PTECs, increased in patients with DKD as compared with the non-DKD.

CONCLUSION

This study demonstrates the involvement of miR-196b-5p-EVs pathway as a novel mechanism in aldosterone-induced renal fibrosis in diabetes. EVs rich in miR-196b-5p mediate the crosstalk between PTECs and fibroblast during the development of renal fibrosis, which might be associated with STAT3/SOCO2 signaling pathway.

Zi Shen Huo Luo Formula Enhances the Therapeutic Effects of Angiotensin-Converting Enzyme Inhibitors on Hypertensive Left Ventricular Hypertrophy by Interfering With Aldosterone Breakthrough and Affecting Caveolin-1/Mineralocorticoid Receptor Colocalization and Downstream Extracellular Signal-Regulated Kinase Signaling

Left ventricular hypertrophy (LVH) is an important characteristic of hypertensive heart disease. Renin-angiotensin system (RAS) blockers have been shown to be effective drugs for the reversal of LVH. Clinical and experimental studies have shown that Zi Shen Huo Luo Formula (ZSHLF) can improve the efficacy of perindopril in the treatment of hypertensive LVH, but its mechanism is unclear. This study aimed to investigate the possible mechanism to improve the efficacy of perindopril. First, we identified 23 compounds in ZSHLF by ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analysis, among which ferulic acid, caffeic acid, vanillic acid, berberine, rutin, quercetin, kaempferol, stachydrine, and tiliroside have been reported to reduce blood pressure and exhibit cardioprotective effects. Second, we treated spontaneously hypertensive rats (SHRs) with perindopril and ZSHLF for 12 continuous weeks and found that chronic use of perindopril could increase the aldosterone (ALD) levels and cause aldosterone breakthrough (ABT). ZSHLF combined with perindopril reduced the ALD levels, interfered with ABT, decreased blood pressure, improved left ventricular diastolic dysfunction, and decreased the collagen volume fraction; these effects were superior to those of perindopril alone. In vitro experiments, ALD-induced cardiomyocytes (H9c2 cells) and cardiac fibroblasts were treated with ZSHLF-containing serum, which suppressed ALD-induced cardiomyocyte hypertrophy and cardiac fibroblast proliferation, increased mineralocorticoid receptor (MR) and Cav-1 colocalization and decreased phosphorylated epidermal growth factor receptor (pEGFR) and phosphorylated extracellular signal-regulated kinase (pERK) protein expression the cells. In conclusion, ZSHLF can interfere with ABT and affect the pathological role of ALD by affecting MR and Cav-1 interactions and EGFR/ERK signaling pathway. These effects represent a possible mechanism by which ZSHLF improves the efficacy of angiotensin-converting enzyme inhibitors (ACEIs) in hypertensive LVH treatment. However, the major bioactive components or metabolites responsible for the effects and the implications of these findings in patients need further verification.

A randomized controlled study of finerenone versus placebo in Japanese patients with type 2 diabetes mellitus and diabetic nephropathy

AIMS

Finerenone (BAY 94-8862) is a novel non-steroidal mineralocorticoid receptor antagonist. The aim of this study was to compare the efficacy and safety of seven once-daily oral doses of finerenone (1.25-20mg) and placebo in 96 patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN) receiving a RAS blocker.

METHODS

ARTS-DN Japan was a multicenter, randomized, double-blind, placebo-controlled, phase 2b study.

RESULTS

Analysis of the urinary albumin-to-creatinine ratio (UACR) at day 90 relative to baseline indicated a nominally significant effect of finerenone. The UACR at day 90 relative to baseline for each finerenone treatment group was numerically reduced compared with placebo. No serious adverse events (AEs) or deaths were reported and no patients experienced treatment-emergent AEs resulting in discontinuation of study drug. Small mean increases in serum potassium level were observed in the finerenone treatment groups (0.025-0.167mmol/L) compared with the placebo group (-0.075mmol/L); no patients developed hyperkalemia.

CONCLUSION

When given in addition to a RAS inhibitor, finerenone reduced albuminuria without adverse effects on serum potassium levels or renal function in Japanese patients with T2DM and DN.