30 YEARS OF THE MINERALOCORTICOID RECEPTOR: The role of the mineralocorticoid receptor in the vasculature

A second act for spironolactone: cognitive benefits in renal dysfunction - a critical review

Renal dysfunction or Chronic kidney disease (CKD) are increasingly associated with cognitive deficit and memory impairment, suggesting a crucial kidney-brain axis. This review examines spironolactone's emerging role as a neuroprotective agent in the context of renal dysfunction-induced cognitive impairment. As a selective mineralocorticoid receptor (MR) antagonist, spironolactone demonstrates multifaceted protective mechanisms beyond its well established renoprotective effects. Evidences also suggests that spironolactone attenuates neuroinflammation, mitigates oxidative stress in brain, preserve blood-brain barrier (BBB) integrity and regulates hormonal imbalances associated with renal dysfunction. This review focuses on the reported beneficial effects of spironolactone in various neurodegenerative diseases (NDDs). These mechanisms collectively protect against the neurodegeneration in memory impairment induced by renal dysfunction. The dual action of spironolactone on both renal and cerebral tissues presents a novel therapeutic advantage in addressing this complex pathophysiology. This study elucidates multiple beneficial mechanisms by which spironolactone addresses cognitive impairment associated with renal dysfunction. Spironolactone enhances BBB protection and restores BBB integrity which is often compromised with renal dysfunction. It promotes neuroplasticity (allowing for improved neural adaptation and cognitive function), additionally mediates cerebral blood flow (CBF) ensuring adequate oxygen and nutrient delivery to brain. Spironolactone's anti-inflammatory effects by inhibiting the nuclear factor-kappa B (NF-κB) pathway and modulation of neuregulin1 (NRG1)/v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 4 (ERBB4) signaling effectively reduce neuroinflammation that contributes to memory impairment. It also mitigates oxidative stress by targeting NADPH-oxidase (NOX), a major source of reactive oxygen species (ROS) in the central nervous system (CNS). Spironolactone also maintains hormonal balance, particularly regarding aldosterone levels, which become dysregulated in renal dysfunction and negatively impact brain function. These insights provide new possibilities for developing targeted therapies against renal dysfunction-induced memory impairment.

Aldosterone-Induced Transformation of Vascular Smooth Muscle Cells into Macrophage-like Cells Participates in Inflammatory Vascular Lesions

Vascular smooth muscle cells (VSMCs) are the most abundant cell type in blood vessels, participating in cardiovascular diseases in various ways, among which their transformation into macrophage-like cells has become a research hotspot. In this study, rats were infused with aldosterone for 12 weeks, and VSMCs stimulated with aldosterone in vitro were used to observe aortic injury and the role of VSMC transformation. Vascular changes were detected via small animal ultrasound and H&E staining. Moreover, immunohistochemistry, immunofluorescence, Western blot, and flow cytometry were used to verify that the transformation of VSMCs into macrophage-like cells is regulated by mineralocorticoid receptor (MR) activation and macrophage colony-stimulating factor (M-CSF) and its receptor. Rat vasculature and in vitro cellular experiments revealed that VSMCs transformed into macrophage-like cells and secreted inflammatory factors such as interleukin-1β (IL-1β) and monocyte chemoattractant protein-1 (MCP-1), thereby exacerbating inflammatory vascular lesions, which was inhibited by the MR antagonist esaxerenone. These results reveal that increased levels of aldosterone activate MR, leading to the secretion of M-CSF by VSMCs. This further promotes the transformation of VSMCs into macrophage-like cells, which participate in inflammatory vascular lesions. Therefore, inhibiting the formation of macrophage-like cells can effectively reduce inflammatory vascular lesions.

Mineralocorticoid receptor antagonists and heart failure with preserved ejection fraction: current understanding and future prospects

The mineralocorticoid receptor (MR), part of the steroid hormone receptor subfamily within nuclear hormone receptors, is found in the kidney and various non-epithelial tissues, including the heart and blood vessels. When improperly activated, it can contribute to heart failure processes such as cardiac hypertrophy, fibrosis, stiffening of arteries, inflammation, and oxidative stress. MR antagonists (MRAs) have shown clear clinical benefits in patients with heart failure with reduced ejection fraction (HFrEF). However, in cases of heart failure with preserved ejection fraction (HFpEF), there is considerable diversity due to its complex underlying mechanisms, resulting in conflicting findings regarding the effectiveness of MRAs in relevant studies. The concept of phenomapping presents an encouraging avenue for investigating different intervention targets and novel therapies for HFpEF. Post hoc analysis of the TOPCAT trial identified certain HFpEF phenotypes that responded favorably to spironolactone. Growing clinical and preclinical evidence suggests that non-steroidal MRAs, which exhibit greater receptor selectivity, stronger anti-fibrotic and anti-inflammatory properties, and fewer hormone-related side effects, may emerge as another promising treatment option for HFpEF alongside sodium-glucose co-transporter 2 (SGLT2) inhibitors. This review aims to outline the structural and functional characteristics of MR, discuss the physiological effects of its activation and inhibition, and delve into the potential for personalized MRA therapy based on the concept of HFpEF phenotype.

Finerenone: Will It Be a Game-changer?

Heart failure (HF) is a major contributor to hospitalisations and accounts for 7% of cardiovascular-related deaths, with patients who have chronic kidney disease and type 2 diabetes at heightened risk. Existing treatment guidelines inadequately address these comorbidities. Steroidal mineralocorticoid receptor antagonists (MRAs) are commonly used in HF with reduced ejection fraction but pose risks, such as hyperkalaemia and acute kidney injury. Finerenone, a non-steroidal MRA, offers a safer alternative, with higher selectivity, reduced electrolyte disturbances and beneficial effects on heart and kidney tissues. Preclinical studies show anti-inflammatory and anti-fibrotic effects, while phase III trials (ARTS and ARTS-HF) demonstrated fewer hyperkalaemia incidents compared with spironolactone. In phase III trials (FIDELIO-DKD and FIGARO-DKD), finerenone reduced HF hospitalisations by 22% in patients with chronic kidney disease and type 2 diabetes. The FINEARTS-HF trial found that finerenone significantly reduced the risk of worsening HF events or CV death in patients with HF with mildly reduced or preserved ejection fraction. Its combination with therapies, such as sodium-glucose cotransporter 2 inhibitors, shows promise and ongoing trials, such as REDEFINE-HF, FINALITY-HF and CONFIRMATION-HF, are investigating its efficacy in other HF phenotypes. These studies will further establish the role of finerenone in managing cardio-renal-metabolic diseases.

Mineralocorticoid receptor antagonism prevents coronary microvascular dysfunction in intermittent hypoxia independent of blood pressure

STUDY OBJECTIVES

Obstructive sleep apnea (OSA), characterized by intermittent hypoxia (IH), and is associated with increased cardiovascular mortality that may not be reduced by standard therapies. Inappropriate activation of the renin-angiotensin-aldosterone system occurs in IH, and mineralocorticoid receptor (MR) blockade has been shown to improve vascular outcomes in cardiovascular disease. Thus, we hypothesized that MR inhibition prevents coronary and renal vascular dysfunction in mice exposed to chronic IH.

METHODS

Human and mouse coronary vascular cells and male C57BL/6J mice were exposed to IH or room air (RA) for 12 hours/day for 3 days (in vitro) and 6 weeks with or without treatments with spironolactone (SPL) or hydrochlorothiazide (HTZ).

RESULTS

In vitro studies demonstrated that IH increased MR gene expression in human and mouse coronary artery endothelial and smooth muscle cells. Exposure to IH in mice increased blood pressure, reduced coronary flow velocity reserve (CFVR), and attenuated endothelium-dependent dilation and enhanced vasoconstrictor responsiveness in coronary, but not renal arteries. Importantly, SPL treatment prevented altered coronary vascular function independent of blood pressure as normalization of BP with HTZ did not improve CFVR or coronary vasomotor function.

CONCLUSIONS

These data demonstrate that chronic IH, which mimics the hypoxia-reoxygenation cycles of moderate-to-severe OSA, increases coronary vascular MR expression in vitro. It also selectively promotes coronary vascular dysfunction in mice. Importantly, this dysfunction is sensitive to MR antagonism by SPL, independent of blood pressure. These findings suggest that MR blockade could serve as an adjuvant therapy to improve long-term cardiovascular outcomes in patients with OSA.

Obesity, aldosterone excess, and mineralocorticoid receptor activation: Parallel or intersected circumstances?

The obesity pandemic, with its associated comorbidities of hypertension and diabetes, constitutes a global public health issue. Importantly, there is an increasing prevalence of aldosterone excess related to obesity and resultant poor health outcomes. Nevertheless, the association between aldosterone and obesity still needs to be clarified. In this review, the authors discuss the role of white adipose tissue in linking obesity, aldosterone excess, and hypertension. The consequences of aldosterone excess in obesity are presented as genomic, non-genomic, and non-epithelial effects. Moreover, the authors emphasize the value of interference with aldosterone pathophysiology (as with mineralocorticoid antagonists) in obesity, thus reducing the adverse clinical impact of aldosterone in myocardial infarction, heart failure, kidney dysfunction, and associated mortality.

Mineralocorticoid Receptor and Sleep Quality in Chronic Kidney Disease

The classical function of the mineralocorticoid receptor (MR) is to maintain electrolytic homeostasis and control extracellular volume and blood pressure. The MR is expressed in the central nervous system (CNS) and is involved in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis as well as sleep physiology, playing a role in the non-rapid eye movement (NREM) phase of sleep. Some patients with psychiatric disorders have very poor sleep quality, and a relationship between MR dysregulation and this disorder has been found in them. In addition, the MR is involved in the regulation of the renal peripheral clock. One of the most common comorbidities observed in patients with chronic kidney disease (CKD) is poor sleep quality. Patients with CKD experience sleep disturbances, including reduced sleep duration, sleep fragmentation, and insomnia. To date, no studies have specifically investigated the relationship between MR activation and CKD-associated sleep disturbances. However, in this review, we analyzed the environment that occurs in CKD and proposed two MR-related mechanisms that may be responsible for these sleep disturbances: the circadian clock disruption and the high levels of MR agonist observed in CKD.

Role of L-type Ca2+-channels in the vasorelaxing response to finerenone in arteries of human visceral adipose tissue

Inadequate blood supply to the expanding adipose tissue (AT) is involved in the unhealthy AT remodeling and cardiometabolic consequences of obesity. Because of the pathophysiological role of upregulated mineralocorticoid receptor (MR) signaling in the complications of obesity, this study tested the vasoactive properties of finerenone, a nonsteroidal MR antagonist, in arteries of human AT. Arteries isolated from the visceral AT of obese subjects were studied in a wire myograph. Finerenone resulted in a concentration-dependent relaxation of arteries precontracted with either the thromboxane-A2 analog U46619, ET-1, or high-K+ solution; the steroidal MR antagonist potassium canrenoate, by contrast, did not relax arteries contracted with either U46619 or high-K+ solution. Finerenone-induced relaxation after precontraction with U46619 was greater in the arteries of obese versus nonobese subjects. Mechanistically, the vasorelaxing response to finerenone was not influenced by preincubation with the nitric oxide synthase inhibitor L-NAME or by endothelium removal. Interestingly, finerenone, like the dihydropyridine Ca2+-channel blocker nifedipine, relaxed arteries contracted with the L-type Ca2+-channel agonist Bay K8644. In conclusion, finerenone relaxes arteries of human visceral AT, likely through antagonism of L-type Ca2+ channels. This finding identifies a novel mechanism by which finerenone may improve AT perfusion, hence protecting against the cardiometabolic complications of obesity.

Aldosterone's impact on kidney health: exploring the benefits of mineralocorticoid receptor antagonists for renal protection

Aldosterone, a hormone synthesized by the adrenal cortex, plays a crucial role in regulating sodium and potassium levels in the kidneys through interaction with the mineralocorticoid receptor (MR) in the distal tubules and collecting ducts. While aldosterone aids in maintaining fluid balance by promoting sodium reabsorption and potassium secretion, elevated levels can lead to inflammation, oxidative stress, and organ damage. Experimental evidence highlights aldosterone's involvement in renal inflammation, collagen deposition, and fibrosis, often exacerbating the effects of therapies like angiotensin-converting enzyme inhibitors (ACEIs) by increasing proteinuria and vascular damage. Conversely, mineralocorticoid receptor antagonists (MRAs) show promise in mitigating these harmful effects. This review integrates current knowledge on aldosterone and MRAs, emphasizing their roles in renal health from both clinical and experimental perspectives. Additionally, the novel drug finerenone has shown favorable renal and cardiovascular outcomes in patients with diabetes and chronic kidney disease (CKD), warranting exploration of its potential use in other disease populations in future research.

Human and fish differences in steroid receptors activation: A review

Steroid receptors (SRs) are transcription factors activated by steroid hormones (SHs) that belong to the nuclear receptors (NRs) superfamily. Several studies have shown that SRs are targets of endocrine disrupting chemicals (EDCs), widespread substances in the environment capable of interfering with the endogenous hormonal pathways and causing adverse health effects in living organisms and/or their progeny. Cell lines with SRs reporter gene are currently used for in vitro screening of large quantities of chemicals with suspected endocrine-disrupting activities. However, most of these cell lines express human SRs and therefore the toxicological data obtained are also extrapolated to non-mammalian species. In parallel, in vivo tests have recently been developed on fish species whose data are also extrapolated to mammalian species. As some species-specific differences in SRs activation by natural and synthetic chemicals have been recently reported, the aim of this review is to summarize those between human and fish SRs, as representatives of mammalian and non-mammalian toxicology, respectively. Overall, this literature study aims to improve inter-species extrapolation of toxicological data on EDCs and to understand which reporter gene cell lines expressing human SRs are relevant for the assessment of effects in fish and whether in vivo tests on fish can be properly used in the assessment of adverse effects on human health.

Prevalence and impact of diabetes and prediabetes on presentation and complications of primary hyperaldosteronism at diagnosis

BACKGROUND

Primary hyperaldosteronism (PH) is considered to contribute to increased risk of developing type 2 diabetes mellitus (T2DM) and prediabetes. Both PH and DM are associated with increased risk for hypertension, cardiovascular diseases, and chronic kidney diseases. However, data on prevalence of T2DM and prediabetes in PH, and impact of T2DM and prediabetes on presentation and cardio renal complications in PH at presentation is sparse.

AIM

To determine the prevalence of T2DM and prediabetes in PH at diagnosis and impact on presentation and complications of PH.

METHODS

A retrospective cohort study was conducted in tertiary care settings in individuals with confirmed diagnosis of PH at presentation. Demographic variables, clinical presentations, duration and degree of hypertension, complications, laboratory parameters including sodium, potassium levels, plasma aldosterone concentration (PAC), plasma renin activity (PRA), and aldosterone to renin ratio (ARR) and cardio-renal parameters were collected. Comparison was done between three groups: PH with no DM (Group A) or with pre-diabetes (Group B) or with T2DM (Group C). P < 0.05 was statistically significant.

RESULTS

Among 78 individuals with confirmed PH, 62% had pre-diabetes or diabetes; with 37% having DM. Mean duration of T2DM was 5.97 ± 4.7 years. The mean levels of glycaemic parameters among the group A vs B vs C individuals were fasting plasma glucose (mg/dL): 87.9 ± 6.5, 105.4 ± 9.02, 130.6 ± 21.1; post prandial plasma glucose (mg/dL): 122.7 ± 9.8, 154.9 ± 14, 196.7 ± 38.0; glycated haemoglobin (%) (5.3 ± 0.2, 5.9 ± 0.2, 7.5 ± 0.6, P < 0.05), respectively. There was no significant difference in the biochemical parameters (PAC, PRA, ARR, sodium, potassium levels), presentation and complications between the groups. Cardio renal parameters or degree and duration of hypertension were comparable between the groups.

CONCLUSION

Significant prevalence of T2DM and prediabetes in PH at diagnosis does not impact its presentation or complications. Early screening for undetected PH in T2DM and prediabetes subjects with hypertension may prevent complications.

Mineralocorticoid Receptors in Vascular Smooth Muscle: Blood Pressure and Beyond

After half a century of evidence suggesting the existence of mineralocorticoid receptors (MR) in the vasculature, the advent of technology to specifically knockout the MR from smooth muscle cells (SMCs) in mice has elucidated contributions of SMC-MR to cardiovascular function and disease, independent of the kidney. This review summarizes the latest understanding of the molecular mechanisms by which SMC-MR contributes to (1) regulation of vasomotor function and blood pressure to contribute to systemic and pulmonary hypertension; (2) vascular remodeling in response to hypertension, vascular injury, obesity, and aging, and the impact on vascular calcification; and (3) cardiovascular pathologies including aortic aneurysm, heart valve dysfunction, and heart failure. Data are reviewed from in vitro studies using SMCs and in vivo findings from SMC-specific MR-knockout mice that implicate target genes and signaling pathways downstream of SMC-MR. By regulating expression of the L-type calcium channel subunit Cav1.2 and angiotensin II type-1 receptor, SMC-MR contributes to myogenic tone and vasoconstriction, thereby contributing to systemic blood pressure. MR activation also promotes SMC proliferation, migration, production and degradation of extracellular matrix, and osteogenic differentiation by regulating target genes including connective tissue growth factor, osteopontin, bone morphogenetic protein 2, galectin-3, and matrix metallopeptidase-2. By these mechanisms, SMC-MR promotes disease progression in models of aging-associated vascular stiffness, vascular calcification, mitral and aortic valve disease, pulmonary hypertension, and heart failure. While rarely tested, when sexes were compared, the mechanisms of SMC-MR-mediated disease were sexually dimorphic. These advances support targeting SMC-MR-mediated mechanisms to prevent and treat diverse cardiovascular disorders.

The Mineralocorticoid Receptor in the Vasculature: Friend or Foe?

Originally described as the renal aldosterone receptor that regulates sodium homeostasis, it is now clear that mineralocorticoid receptors (MRs) are widely expressed, including in vascular endothelial and smooth muscle cells. Ample data demonstrate that endothelial and smooth muscle cell MRs contribute to cardiovascular disease in response to risk factors (aging, obesity, hypertension, atherosclerosis) by inducing vasoconstriction, vascular remodeling, inflammation, and oxidative stress. Extrapolating from its role in disease, evidence supports beneficial roles of vascular MRs in the context of hypotension by promoting inflammation, wound healing, and vasoconstriction to enhance survival from bleeding or sepsis. Advances in understanding how vascular MRs become activated are also reviewed, describing transcriptional, ligand-dependent, and ligand-independent mechanisms. By synthesizing evidence describing how vascular MRs convert cardiovascular risk factors into disease (the vascular MR as a foe), we postulate that the teleological role of the MR is to coordinate responses to hypotension (the MR as a friend).

Overview of the safety, efficiency, and potential mechanisms of finerenone for diabetic kidney diseases

Diabetic kidney disease (DKD) is a common disorder with numerous severe clinical implications. Due to a high level of fibrosis and inflammation that contributes to renal and cardiovascular disease (CVD), existing treatments have not effectively mitigated residual risk for patients with DKD. Excess activation of mineralocorticoid receptors (MRs) plays a significant role in the progression of renal and CVD, mostly by stimulating fibrosis and inflammation. However, the application of traditional steroidal MR antagonists (MRAs) to DKD has been limited by adverse events. Finerenone (FIN), a third-generation non-steroidal selective MRA, has revealed anti-fibrotic and anti-inflammatory effects in pre-clinical studies. Current clinical trials, such as FIDELIO-DKD and FIGARO-DKD and their combined analysis FIDELITY, have elucidated that FIN reduces the kidney and CV composite outcomes and risk of hyperkalemia compared to traditional steroidal MRAs in patients with DKD. As a result, FIN should be regarded as one of the mainstays of treatment for patients with DKD. In this review, the safety, efficiency, and potential mechanisms of FIN treatment on the renal system in patients with DKD is reviewed.

Cardiorenal benefits of finerenone: protecting kidney and heart

Persons with diabetes and chronic kidney disease (CKD) have a high residual risk of developing cardiovascular (CV) complications despite treatment with renin-angiotensin system blockers and sodium-glucose cotransporter type 2 inhibitors. Overactivation of mineralocorticoid receptors plays a key role in the progression of renal and CV disease, mainly by promoting inflammation and fibrosis. Finerenone is a nonsteroidal selective mineralocorticoid antagonist. Recent clinical trials, such as FIDELIO-DKD and FIGARO-DKD and the combined analysis FIDELITY have demonstrated that finerenone decreases albuminuria, risk of CKD progression, and CV risk in subjects with type 2 diabetes (T2D) and CKD. As a result, finerenone should thus be considered as part of a holistic approach to kidney and CV risk in persons with T2D and CKD. In this narrative review, the impact of finerenone treatment on the CV system in persons with type 2 diabetes and CKD is analyzed from a practical point of view.Key messages:Despite inhibition of renin-angiotensin system and sodium-glucose cotransporter type 2, persons with type 2 diabetes (T2D) and chronic kidney disease (CKD) remain on high cardiovascular (CV) residual risk.Overactivation of mineralocorticoid receptors plays a key role in the progression of renal and CV disease, mainly by promoting inflammation and fibrosis that is not targeted by traditional treatments.Finerenone is a nonsteroidal selective mineralocorticoid antagonist that decreases not only albuminuria, but also the risk of CKD progression, and CV risk in subjects with T2D and CKD.

The efficacy of percutaneous transluminal angioplasty and arteriovenous fistula reconstruction for immature arteriovenous fistula

BACKGROUND

To access the efficacy of percutaneous transluminal angioplasty and arteriovenous fistula reconstruction for immature arteriovenous fistula, compare the long-term patency and post-operative complications between them.

MATERIALS AND METHODS

The medical records and Hemodialysis record sheets from 44 patients between May 2020 and January 2022 who underwent percutaneous transluminal angioplasty or arteriovenous fistula reconstruction treatment for immature autogenous arteriovenous fistula (AVF) were retrospectively reviewed. The patients were divided into two groups according to the type of surgery they received, including 25 patients in the PTA group and 19 patients in the AVF reconstruction group. Clinical outcomes were included, such as the primary and secondary patency rates following the procedure, maturation time, peak systolic velocity (PSV) of brachial artery, maximum pump-controlled blood flow at initial dialysis, and post-operative complications rates in the two groups.

RESULTS

Technical and clinical success was achieved in 100% of the 44 cases. For patients who underwent percutaneous transluminal angioplasty, the primary patency rate at 3, 6, and 9 months was 84.0%, 68.0%, 60.0%, and the secondary patency rate was 92.0%, 84.0%, 80.0%, respectively. And for patients who underwent arteriovenous fistula reconstruction, the primary patency rate at 3, 6, and 9 months was 89.5%, 73.7%, 68.4%, and the secondary patency rate was 100.0%, 94.7%, 94.7%, respectively. There were no significant differences between the two groups in terms of patency rates (p > .050). In patients whose maturation was successful, the average maturation time of fistula after the PTA procedure was 19.36 ± 13.94 days, and 58.63 ± 18.95 days for the reconstruction procedure (p < .010). The PSV of brachial artery before and after the procedure was 87.64 ± 23.87 cm/s and 153.20 ± 21.69 cm/s in PTA group, for reconstruction group, the number was 86.26 ± 20.59 cm/s and 151.26 ± 29.94 cm/s, respectively. No statistically significant differences (p > .050). The maximum pump-controlled blood flow at initial dialysis was 232.60 ± 16.72 ml/min in PTA group, which was significantly higher than 197.11 ± 10.45 ml/min in reconstruction group (p < .010). Subcutaneous hematoma, restenosis, thrombus formation, and pseudoaneurysm were major complications in PTA group. Restenosis, thrombus formation, and pseudoaneurysm were major complications in reconstruction group, with no statistically significant differences between the two groups (p > .050).

CONCLUSION

When immature AVFs require reconstruction surgery, the patency outcomes are comparable to AVFs that undergo successful management by PTA. While, when AVFs are successfully managed by PTA, they have significantly less maturation times and higher maximum pump-controlled blood flow rates at initial dialysis AVF use.

Vascular endothelial mineralocorticoid receptors and epithelial sodium channels in metabolic syndrome and related cardiovascular disease

Metabolic syndrome is a group of risk factors that increase the risk of developing metabolic and cardiovascular disease (CVD) and include obesity, dyslipidemia, insulin resistance, atherosclerosis, hypertension, coronary artery disease, and heart failure. Recent research indicates that excessive production of aldosterone and associated activation of mineralocorticoid receptors (MR) impair insulin metabolic signaling, promote insulin resistance, and increase the risk of developing metabolic syndrome and CVD. Moreover, activation of specific epithelial sodium channels (ENaC) in endothelial cells (EnNaC), which are downstream targets of endothelial-specific MR (ECMR) signaling, are also believed to play a crucial role in the development of metabolic syndrome and CVD. These adverse effects of ECMR/EnNaC activation are mediated by increased oxidative stress, inflammation, and lipid metabolic disorders. It is worth noting that ECMR/EnNaC activation and the pathophysiology underlying metabolic syndrome and CVD appears to exhibit sexual dimorphism. Targeting ECMR/EnNaC signaling may have a beneficial effect in preventing insulin resistance, diabetes, metabolic syndrome, and related CVD. This review aims to examine our current understanding of the relationship between MR activation and increased metabolic syndrome and CVD, with particular emphasis placed on the role for endothelial-specific ECMR/EnNaC signaling in these pathological processes.

Finerenone: towards a holistic therapeutic approach to patients with diabetic kidney disease

Despite current treatments, which include renin angiotensin system blockers and SGLT2 inhibitors, the risk of progression of kidney disease among patients with diabetes and chronic kidney disease (CKD) remains unacceptably high. The pathogenesis of CKD in patients with diabetes is complex and includes hemodynamic and metabolic factors, as well as inflammation and fibrosis. Finerenone is a highly selective nonsteroidal mineralocorticoid antagonist that, in contrast to current therapies, may directly reduce inflammation and fibrosis, thus adding value in the management of these patients. In fact, finerenone decreases albuminuria and slows CKD progression in persons with diabetes. We now review the mechanisms of action of finerenone, the results of recent clinical trials, and the integration of the kidney and cardiovascular protection afforded by finerenone in the routine care of patients with diabetes and CKD.

Epigenetic modification in diabetic kidney disease

Diabetic kidney disease (DKD) is a common microangiopathy in diabetic patients and the main cause of death in diabetic patients. The main manifestations of DKD are proteinuria and decreased renal filtration capacity. The glomerular filtration rate and urinary albumin level are two of the most important hallmarks of the progression of DKD. The classical treatment of DKD is controlling blood glucose and blood pressure. However, the commonly used clinical therapeutic strategies and the existing biomarkers only partially slow the progression of DKD and roughly predict disease progression. Therefore, novel therapeutic methods, targets and biomarkers are urgently needed to meet clinical requirements. In recent years, increasing attention has been given to the role of epigenetic modification in the pathogenesis of DKD. Epigenetic variation mainly includes DNA methylation, histone modification and changes in the noncoding RNA expression profile, which are deeply involved in DKD-related inflammation, oxidative stress, hemodynamics, and the activation of abnormal signaling pathways. Since DKD is reversible at certain disease stages, it is valuable to identify abnormal epigenetic modifications as early diagnosis and treatment targets to prevent the progression of end-stage renal disease (ESRD). Because the current understanding of the epigenetic mechanism of DKD is not comprehensive, the purpose of this review is to summarize the role of epigenetic modification in the occurrence and development of DKD and evaluate the value of epigenetic therapies in DKD.

Aldosterone: Renal Action and Physiological Effects

Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.

Cardiovascular Disease in Obstructive Sleep Apnea: Putative Contributions of Mineralocorticoid Receptors

Obstructive sleep apnea (OSA) is a chronic and highly prevalent condition that is associated with oxidative stress, inflammation, and fibrosis, leading to endothelial dysfunction, arterial stiffness, and vascular insulin resistance, resulting in increased cardiovascular disease and overall mortality rates. To date, OSA remains vastly underdiagnosed and undertreated, with conventional treatments yielding relatively discouraging results for improving cardiovascular outcomes in OSA patients. As such, a better mechanistic understanding of OSA-associated cardiovascular disease (CVD) and the development of novel adjuvant therapeutic targets are critically needed. It is well-established that inappropriate mineralocorticoid receptor (MR) activation in cardiovascular tissues plays a causal role in a multitude of CVD states. Clinical studies and experimental models of OSA lead to increased secretion of the MR ligand aldosterone and excessive MR activation. Furthermore, MR activation has been associated with worsened OSA prognosis. Despite these documented relationships, there have been no studies exploring the causal involvement of MR signaling in OSA-associated CVD. Further, scarce clinical studies have exclusively assessed the beneficial role of MR antagonists for the treatment of systemic hypertension commonly associated with OSA. Here, we provide a comprehensive overview of overlapping mechanistic pathways recruited in the context of MR activation- and OSA-induced CVD and propose MR-targeted therapy as a potential avenue to abrogate the deleterious cardiovascular consequences of OSA.

Emerging vascular cell-specific roles for mineralocorticoid receptor: implications for understanding sex differences in cardiovascular disease

As growing evidence implicates extrarenal mineralocorticoid receptor (MR) in cardiovascular disease (CVD), recent studies have defined both cell- and sex-specific roles. MR is expressed in vascular smooth muscle (SMC) and endothelial cells (ECs). This review integrates published data from the past 5 years to identify novel roles for vascular MR in CVD, with a focus on understanding sex differences. Four areas are reviewed in which there is recently expanded understanding of the cell type- or sex-specific role of MR in 1) obesity-induced microvascular endothelial dysfunction, 2) vascular inflammation in atherosclerosis, 3) pulmonary hypertension, and 4) chronic kidney disease (CKD)-related CVD. The review focuses on preclinical data on each topic describing new mechanistic paradigms, cell type-specific mechanisms, sexual dimorphism if addressed, and clinical implications are then considered. New data support that MR drives vascular dysfunction induced by cardiovascular risk factors via sexually dimorphic mechanisms. In females, EC-MR contributes to obesity-induced endothelial dysfunction by regulating epithelial sodium channel expression and by inhibiting estrogen-induced nitric oxide production. In males with hyperlipidemia, EC-MR promotes large vessel inflammation by genomic regulation of leukocyte adhesion molecules, which is inhibited by the estrogen receptor. In pulmonary hypertension models, MRs in EC and SMC contribute to distinct components of disease pathologies including pulmonary vessel remodeling and RV dysfunction. Despite a female predominance in pulmonary hypertension, sex-specific roles for MR have not been explored. Vascular MR has also been directly implicated in CKD-related vascular dysfunction, independent of blood pressure. Despite these advances, sex differences in MR function remain understudied.

The Mineralocorticoid Receptor Functions as a Key Glucose Regulator in the Skeletal Muscle of Zebrafish

Glucocorticoids (GCs) are essential for maintaining energy homeostasis as part of the adaptive stress response. Most work to date has characterized the metabolic role of GCs via the activation of the glucocorticoid receptor (nr3c1; GR), which is activated under high GC conditions. However, GCs also bind to the mineralocorticoid receptor (nr3c2; MR), a high-affinity corticosteroid receptor active under basal GC conditions. Despite the expression of MR in skeletal muscles, almost nothing is known about its physiological role. Here we tested the hypothesis that the MR promotes anabolic processes during resting cortisol levels and curtails the catabolic actions of the GR during high (stressed) levels of cortisol. To determine the effect of MR, a zebrafish line with a ubiquitous MR knockout (MRca402/ca402) was utilized. The GR was activated in the same group by chronically treating fish with exogenous cortisol. In the muscle, MR primarily promoted nutrient storage, and restricted energy substrate mobilization under resting conditions, whereas GR activation resulted in increased nutrient utilization. Interestingly, MR loss improved GR-driven metabolic flexibility, suggesting that the activation state of these receptors is a key determinant of skeletal muscle ability to switch fuel sources. To determine if the anabolism-promoting nature of MR was due to an interaction with insulin, fish were co-injected with insulin and the fluorescent glucose analogue 2-NBDG. A loss of MR abolished insulin-stimulated glucose uptake in the skeletal muscle. Taken together, we postulate that MR acts as a key modulator of glucose metabolism in the musculature during basal and stress conditions.

Endothelial and Vascular Smooth Muscle Dysfunction in Hypertension

The development of essential hypertension involves several factors. Vascular dysfunction, characterized by endothelial dysfunction, low-grade inflammation and structural remodeling, plays an important role in the initiation and maintenance of essential hypertension. Although the mechanistic pathways by which essential hypertension develops are poorly understood, several pharmacological classes available on the clinical settings improve blood pressure by interfering in the cardiac output and/or vascular function. This review is divided in two major sections. The first section depicts the major molecular pathways as renin angiotensin aldosterone system (RAAS), endothelin, nitric oxide signalling pathway and oxidative stress in the development of vascular dysfunction. The second section describes the role of some pharmacological classes such as i) RAAS inhibitors, ii) dual angiotensin receptor-neprilysin inhibitors, iii) endothelin-1 receptor antagonists, iv) soluble guanylate cyclase modulators, v) phosphodiesterase type 5 inhibitors and vi) sodium-glucose cotransporter 2 inhibitors in the context of hypertension. Some classes are already approved in the treatment of hypertension, but others are not yet approved. However, due to their potential benefits these classes were included.

High Prevalence of Primary Aldosteronism in Patients with Type 2 Diabetes Mellitus and Hypertension

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. The prevalence of hypertension is higher in patients with diabetes mellitus-2 (DM-2). Following the limited existing data, we prospectively investigated the prevalence of aldosterone excess either as autonomous secretion (PA) or as a hyper-response to stress in hypertensive patients with DM-2 (HDM-2). A total of 137 HDM-2 patients and 61 non-diabetics with essential hypertension who served as controls (EH-C) underwent a combined, overnight diagnostic test, the Dexamethasone–captopril–valsartan test (DCVT) used for the diagnosis of PA and an ultralow dose (0.3 μg) ACTH stimulation test to identify an exaggerated aldosterone response to ACTH stimulation. Twenty-three normotensive individuals served as controls (NC) to define the normal response of aldosterone (ALD) and aldosterone-to-renin ratio (ARR) to the ultralow dose ACTH test. Using post-DCVTALD and ARR from the EH-C, and post-ACTH peak ALD and ARR from the NC, 47 (34.3%) HDM-2 patients were found to have PA, whereas 6 (10.4%) HDM-2 patients without PA (DCVT-negative) exhibited an exaggerated aldosterone response to stress—a prevalence much higher than ever reported. Treatment with mineralocorticoid receptor antagonists (MRAs) induced a significant and permanent reduction of BP in all HDM-2 patients. Early diagnosis and targeted treatment of PA is crucial to prevent any aggravating effect on chronic diabetic complications.

Aldosterone-Induced Sarco/Endoplasmic Reticulum Ca2+ Pump Upregulation Counterbalances Cav1.2-Mediated Ca2+ Influx in Mesenteric Arteries

In mesenteric arteries (MAs), aldosterone (ALDO) binds to the endogenous mineralocorticoid receptor (MR) and increases the expression of the voltage-gated L-type Ca_v1.2 channel, an essential ion channel for vascular contraction, sarcoplasmic reticulum (SR) Ca²⁺ store refilling, and Ca²⁺ spark generation. In mesenteric artery smooth muscle cells (MASMCs), Ca²⁺ influx through Ca_v1.2 is the indirect mechanism for triggering Ca²⁺ sparks. This process is facilitated by plasma membrane-sarcoplasmic reticulum (PM-SR) nanojunctions that drive Ca²⁺ from the extracellular space into the SR via Sarco/Endoplasmic Reticulum Ca²⁺ (SERCA) pump. Ca²⁺ sparks produced by clusters of Ryanodine receptors (RyRs) at PM-SR nanodomains, decrease contractility by activating large-conductance Ca²⁺-activated K⁺ channels (BK_Ca channels), which generate spontaneous transient outward currents (STOCs). Altogether, Ca_v1.2, SERCA pump, RyRs, and BK_Ca channels work as a functional unit at the PM-SR nanodomain, regulating intracellular Ca²⁺ and vascular function. However, the effect of the ALDO/MR signaling pathway on this functional unit has not been completely explored. Our results show that short-term exposure to ALDO (10 nM, 24 h) increased the expression of Ca_v1.2 in rat MAs. The depolarization-induced Ca²⁺ entry increased SR Ca²⁺ load, and the frequencies of both Ca²⁺ sparks and STOCs, while [Ca²⁺]_cyt and vasoconstriction remained unaltered in Aldo-treated MAs. ALDO treatment significantly increased the mRNA and protein expression levels of the SERCA pump, which counterbalanced the augmented Ca_v1.2-mediated Ca²⁺ influx at the PM-SR nanodomain, increasing SR Ca²⁺ content, Ca²⁺ spark and STOC frequencies, and opposing to hyperpolarization-induced vasoconstriction while enhancing Acetylcholine-mediated vasorelaxation. This work provides novel evidence for short-term ALDO-induced upregulation of the functional unit comprising Ca_v1.2, SERCA2 pump, RyRs, and BK_Ca channels; in which the SERCA pump buffers ALDO-induced upregulation of Ca²⁺ entry at the superficial SR-PM nanodomain of MASMCs, preventing ALDO-triggered depolarization-induced vasoconstriction and enhancing vasodilation. Pathological conditions that lead to SERCA pump downregulation, for instance, chronic exposure to ALDO, might favor the development of ALDO/MR-mediated augmented vasoconstriction of mesenteric arteries.

Mineralocorticoid receptor antagonist treatment of established pulmonary arterial hypertension improves interventricular dependence in the SU5416-hypoxia rat model

Treatment with mineralocorticoid receptor (MR) antagonists beginning at the outset of disease, or early thereafter, prevents pulmonary vascular remodeling in preclinical models of pulmonary arterial hypertension (PAH). However, the efficacy of MR blockade in established disease, a more clinically relevant condition, remains unknown. Therefore, we investigated the effectiveness of two MR antagonists, eplerenone (EPL) and spironolactone (SPL), after the development of severe right ventricular (RV) dysfunction in the rat SU5416-hypoxia (SuHx) PAH model. Cardiac magnetic resonance imaging (MRI) in SuHx rats at the end of week 5, before study treatment, confirmed features of established disease including reduced RV ejection fraction and RV hypertrophy, pronounced septal flattening with impaired left ventricular filling and reduced cardiac index. Five weeks of treatment with either EPL or SPL improved left ventricular filling and prevented the further decline in cardiac index compared with placebo. Interventricular septal displacement was reduced by EPL whereas SPL effects were similar, but not significant. Although MR antagonists did not significantly reduce pulmonary artery pressure or vessel remodeling in SuHx rats with established disease, animals with higher drug levels had lower pulmonary pressures. Consistent with effects on cardiac function, EPL treatment tended to suppress MR and proinflammatory gene induction in the RV. In conclusion, MR antagonist treatment led to modest, but consistent beneficial effects on interventricular dependence after the onset of significant RV dysfunction in the SuHx PAH model. These results suggest that measures of RV structure and/or function may be useful endpoints in clinical trials of MR antagonists in patients with PAH.

Mineralocorticoid receptor antagonists in diabetic kidney disease - mechanistic and therapeutic effects

Chronic kidney disease (CKD) is the leading complication in type 2 diabetes (T2D) and current therapies that limit CKD progression and the development of cardiovascular disease (CVD) include angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and sodium-glucose co-transporter 2 (SGLT2) inhibitors. Despite the introduction of these therapeutics, an important residual risk of CKD progression and cardiovascular death remains in patients with T2D. Mineralocorticoid receptor antagonists (MRAs) are a promising therapeutic option in diabetic kidney disease (DKD) owing to the reported effects of mineralocorticoid receptor activation in inflammatory cells, podocytes, fibroblasts, mesangial cells and vascular cells. In preclinical studies, MRAs consistently reduce albuminuria, CKD progression, and activation of fibrotic and inflammatory pathways. DKD clinical studies have similarly demonstrated that steroidal MRAs lead to albuminuria reduction compared with placebo, although hyperkalaemia is a major secondary effect. Non-steroidal MRAs carry a lower risk of hyperkalaemia than steroidal MRAs, and the large FIDELIO-DKD clinical trial showed that the non-steroidal MRA finerenone also slowed CKD progression and reduced the risk of adverse cardiovascular outcomes compared with placebo in patients with T2D. Encouragingly, other non-steroidal MRAs have anti-albuminuric properties in DKD. Whether or not combining MRAs with other renoprotective drugs such as SGLT2 inhibitors might provide additive protective effects warrants further investigation.

Roles of steroid receptors in the lung and COVID-19

COVID-19 symptoms and mortality are largely due to its devastating effects in the lungs. The disease is caused by the SARS (Severe Acute Respiratory Syndrome)-CoV-2 coronavirus, which requires host cell proteins such as ACE2 (angiotensin-converting enzyme 2) and TMPRSS2 (transmembrane serine protease 2) for infection of lung epithelia. The expression and function of the steroid hormone receptor family is important in many aspects that impact on COVID-19 effects in the lung - notably lung development and function, the immune system, and expression of TMPRSS2 and ACE2. This review provides a brief summary of current knowledge on the roles of the steroid hormone receptors [androgen receptor (AR), glucocorticoid receptor (GR), progesterone receptor (PR), mineralocorticoid receptor (MR) and oestrogen receptor (ER)] in the lung, their effects on host cell proteins that facilitate SARS-CoV-2 uptake, and provides a snapshot of current clinical trials investigating the use of steroid receptor (SR) ligands to treat COVID-19.

Mineralocorticoid receptors in pulmonary hypertension and right heart failure: From molecular biology to therapeutic targeting

Pulmonary hypertension (PH) is a devastating condition characterized by pulmonary vascular remodelling, leading to progressive increase in pulmonary artery pressure and subsequent right ventricular failure. Aldosterone and the mineralocorticoid receptor (MR), a nuclear transcription factor, are key drivers of cardiovascular disease and MR antagonists are well-established in heart failure. Now, a growing body of evidence points at a detrimental role of MR in PH. Pharmacological MR blockade attenuated PH and prevented RV failure in experimental models. Mouse models with cell selective MR deletion suggest that this effect is mediated by MR in endothelial cells. While the evidence from experimental studies appears convincing, the available clinical data on MR antagonist use in patients with PH is more controversial. Integrated analysis of clinical data together with MR-dependent molecular alterations may provide insights why some patients respond to MRA treatment while others do not. Potential ways to identify MRA 'responders' include the analysis of underlying PH causes, stage of disease, or sex, as well as new biomarkers.

Vascular cell-specific roles of mineralocorticoid receptors in pulmonary hypertension

Abnormalities that characterize pulmonary arterial hypertension include impairment in the structure and function of pulmonary vascular endothelial and smooth muscle cells. Aldosterone levels are elevated in human pulmonary arterial hypertension and in experimental pulmonary hypertension, while inhibition of the aldosterone-binding mineralocorticoid receptor attenuates pulmonary hypertension in multiple animal models. We explored the role of mineralocorticoid receptor in endothelial and smooth muscle cells in using cell-specific mineralocorticoid receptor knockout mice exposed to sugen/hypoxia-induced pulmonary hypertension. Treatment with the mineralocorticoid receptor inhibitor spironolactone significantly reduced right ventricular systolic pressure. However, this is not reproduced by selective mineralocorticoid receptor deletion in smooth muscle cells or endothelial cells. Similarly, spironolactone attenuated the increase in right ventricular cardiomyocyte area independent of vascular mineralocorticoid receptor with no effect on right ventricular weight or interstitial fibrosis. Right ventricular perivascular fibrosis was significantly decreased by spironolactone and this was reproduced by specific deletion of mineralocorticoid receptor from endothelial cells. Endothelial cell-mineralocorticoid receptor deletion attenuated the sugen/hypoxia-induced increase in the leukocyte-adhesion molecule, E-selectin, and collagen IIIA1 in the right ventricle. Spironolactone also significantly reduced pulmonary arteriolar muscularization, independent of endothelial cell-mineralocorticoid receptor or smooth muscle cell-mineralocorticoid receptor. Finally, the degree of pulmonary perivascular inflammation was attenuated by mineralocorticoid receptor antagonism and was fully reproduced by smooth muscle cell-specific mineralocorticoid receptor deletion. These studies demonstrate that in the sugen/hypoxia pulmonary hypertension model, systemic-mineralocorticoid receptor blockade significantly attenuates the disease and that mineralocorticoid receptor has cell-specific effects, with endothelial cell-mineralocorticoid receptor contributing to right ventricular perivascular fibrosis and smooth muscle cell-mineralocorticoid receptor participating in pulmonary vascular inflammation. As mineralocorticoid receptor antagonists are being investigated to treat pulmonary arterial hypertension, these findings support novel mechanisms and potential mineralocorticoid receptor targets that mediate therapeutic benefits in patients.

Mineralocorticoid receptor blockade normalizes coronary resistance in obese swine independent of functional alterations in Kv channels

Impaired coronary microvascular function (e.g., reduced dilation and coronary flow reserve) predicts cardiac mortality in obesity, yet underlying mechanisms and potential therapeutic strategies remain poorly understood. Mineralocorticoid receptor (MR) antagonism improves coronary microvascular function in obese humans and animals. Whether MR blockade improves in vivo regulation of coronary flow, a process involving voltage-dependent K⁺ (K_v) channel activation, or reduces coronary structural remodeling in obesity is unclear. Thus, the goals of this investigation were to determine the effects of obesity on coronary responsiveness to reductions in arterial PO₂ and potential involvement of K_v channels and whether the benefit of MR blockade involves improved coronary K_v function or altered passive structural properties of the coronary microcirculation. Hypoxemia increased coronary blood flow similarly in lean and obese swine; however, baseline coronary vascular resistance was significantly higher in obese swine. Inhibition of K_v channels reduced coronary blood flow and augmented coronary resistance under baseline conditions in lean but not obese swine and had no impact on hypoxemic coronary vasodilation. Chronic MR inhibition in obese swine normalized baseline coronary resistance, did not influence hypoxemic coronary vasodilation, and did not restore coronary K_v function (assessed in vivo, ex vivo, and via patch clamping). Lastly, MR blockade prevented obesity-associated coronary arteriolar stiffening independent of cardiac capillary density and changes in cardiac function. These data indicate that chronic MR inhibition prevents increased coronary resistance in obesity independent of K_v channel function and is associated with mitigation of obesity-mediated coronary arteriolar stiffening.

Mineralcorticoid receptor blockers in chronic kidney disease

There are many experimental data supporting the involvement of aldosterone and mineralcorticoid receptor (MR) activation in the genesis and progression of chronic kidney disease (CKD) and cardiovascular damage. Many studies have shown that in diabetic and non-diabetic CKD, blocking the renin-angiotensin-aldosterone (RAAS) system with conversion enzyme inhibitors (ACEi) or angiotensin II receptor blockers (ARBs) decreases proteinuria, progression of CKD and mortality, but there is still a significant residual risk of developing these events. In subjects treated with ACEi or ARBs there may be an aldosterone breakthrough whose prevalence in subjects with CKD can reach 50%. Several studies have shown that in CKD, the aldosterone antagonists (spironolactone, eplerenone) added to ACEi or ARBs, reduce proteinuria, but increase the risk of hyperkalemia. Other studies in subjects treated with dialysis suggest a possible beneficial effect of antialdosteronic drugs on CV events and mortality. Newer potassium binders drugs can prevent/decrease hyperkalemia induced by RAAS blockade, and may reduce the high discontinuation rates or dose reduction of RAAS-blockers. The nonsteroidal MR blockers, with more potency and selectivity than the classic ones, reduce proteinuria and have a lower risk of hyperkalemia. Several clinical trials, currently underway, will determine the effect of classic MR blockers on CV events and mortality in subjects with stage 3b CKD and in dialysis patients, and whether in patients with type 2 diabetes mellitus and CKD, optimally treated and with high risk of CV and kidney events, the addition of finerenone to their treatment produces cardiorenal benefits. Large randomized trials have shown that sodium glucose type 2 cotransporter inhibitors (SGLT2i) reduce mortality and the development and progression of diabetic and nondiabetic CKD. There are pathophysiological arguments, which raise the possibility that the triple combination ACEi or ARBs, SGLT2i and aldosterone antagonist provide additional renal and cardiovascular protection.

New Horizons: Does Mineralocorticoid Receptor Activation by Cortisol Cause ATP Release and COVID-19 Complications?

This paper attempts to explain how the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus causes the complications that make coronavirus disease 2019 (COVID-19) a serious disease in specific patient subgroups. It suggests that cortisol-associated activation of the mineralocorticoid receptor (MR) in epithelial and endothelial cells infected with the virus stimulates the release of adenosine 5'-triphosphate (ATP), which then acts back on purinergic receptors. In the lung this could produce the nonproductive cough via purinergic P2X3 receptors on vagal afferent nerves. In endothelial cells it could stimulate exocytosis of Weibel-Palade bodies (WPBs) that contain angiopoietin-2, which is important in the pathogenesis of acute respiratory distress syndrome (ARDS) by increasing capillary permeability and von Willebrand factor (VWF), which mediates platelet adhesion to the endothelium and hence clotting. Angiopoietin-2 and VWF levels both are markedly elevated in COVID-19-associated ARDS. This paper offers an explanation for the sex differences in SARS-CoV-2 complications and also for why these are strongly associated with age, race, diabetes, and body mass index. It also explains why individuals with blood group A have a higher risk of severe infection than those with blood group O. Dexamethasone has been shown to be of benefit in coronavirus ARDS patients and has been thought to act as an anti-inflammatory drug. This paper suggests that a major part of its effect may be due to suppression of cortisol secretion. There is an urgent need to trial the combination of dexamethasone and an MR antagonist such as spironolactone to more effectively block the MR and hence the exocytosis of WPBs.

Comparison of ambulatory blood pressure between patients with primary aldosteronism and other forms of hypertension

OBJECTIVE

Primary aldosteronism (PA) is a potentially curable cause of hypertension associated with worse cardiovascular prognosis than blood pressure-matched essential hypertension (EH). Effective targeted treatment for PA is available with the greatest benefit seen if treatment is started early, prior to the development of end-organ damage. However, PA is currently substantially under-diagnosed. The standard screening test for PA, the aldosterone-to-renin ratio (ARR), is performed infrequently in both primary and tertiary care. In contrast, ambulatory blood pressure monitoring (ABPM) is frequently utilized in the assessment of hypertension. The aim of this study was to compare ABPM parameters in hypertensive patients with and without PA, in order to identify features of ABPM associated with PA that can prompt screening.

STUDY DESIGN

Patients with PA (n = 55) were identified from a tertiary clinic specializing in the management of endocrine causes of hypertension whilst the controls (n = 389) were consecutive patients with hypertension but without a known diagnosis of PA who were referred for ABPM.

RESULTS

In this study, PA patients were younger and had higher 24-h, day, and night-time blood pressure compared with controls despite similar number of antihypertensive medications. However, there was no significant difference in nocturnal dipping or day-night blood pressure variability between the two groups.

CONCLUSIONS

An elevated ambulatory blood pressure in patients on multiple antihypertensives could suggest underlying PA but in the absence of other distinguishing features, ABPM could not reliably differentiate PA from other forms of hypertension. Routine biochemical screening for PA remained the most reliable way of detecting this treatable secondary cause of hypertension.

Mineralocorticoid receptors in the pathogenesis of insulin resistance and related disorders: from basic studies to clinical disease

Aldosterone is a steroid hormone that regulates blood pressure and cardiovascular function by acting on renal and vascular mineralocorticoid receptors (MRs) to promote sodium retention and modulate endothelial function. Indeed, MRs are expressed in endothelial cells, vascular smooth muscle cells, adipocytes, immune cells, skeletal muscle cells, and cardiomyocytes. Excessive aldosterone and associated MR activation impair insulin secretion, insulin metabolic signaling to promote development of diabetes, and the related cardiometabolic syndrome. These adverse effects of aldosterone are mediated, in part, via increased inflammation, oxidative stress, dyslipidemia, and ectopic fat deposition. Therefore, inhibition of MR activation may have a beneficial effect in prevention of impaired insulin metabolic signaling, type 2 diabetes, and cardiometabolic disorders. This review highlights findings from the recent surge in research regarding MR-related cardiometabolic disorders as well as our contemporary understanding of the detrimental effects of excess MR activation on insulin metabolic signaling.

Drospirenone Effects on the Plasminogen Activator System in Immortalized Human Endometrial Endothelial Cells

Drospirenone (DRSP) is a fourth-generation progestin that interacts with the progesterone receptor (PR) and androgen receptor (AR) in addition to uniquely interacting to the mineralocorticoid receptor (MR). The known effects of DRSP via the mineralocorticoid receptor (MR) are limited. This study seeks to determine if DRSP alters plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) in human immortalized endometrial endothelial cells (HEEC) and if such changes in the plasminogen activator system (PAS) are mediated through the MR or AR. The in vitro cell culture experiments utilizing an immortalized human endometrial endothelial cell line evaluated two concentrations of DRSP on PAI-1 and tPA levels in the culture media using specific enzyme-linked immunoassays (ELISA). Experiments adding DRSP with an androgen receptor blocker, flutamide, or a mineralocorticoid receptor agonist, aldosterone, were performed to elucidate which receptor(s) mediated the PAS effects. DRSP 10 μM significantly decreased both HEEC levels of PAI-1 and tPA to 0.75 ± 0.04 and 0.82 ± 0.05 of control, respectively. These direct effects were blunted by flutamide, an AR antagonist. PAI-1 and tPA were not changed by the MR agonist, aldosterone. DRSP significantly decreased both PAI-1 and tPA in the HEECs via the androgen receptor.

Dietary supplementation of Huangshan Maofeng green tea preventing hypertension of older C57BL/6 mice induced by desoxycorticosterone acetate and salt

Senile hypertension affects the life quality of aged population. Dietary intervention plays a pivotal role in the prevention of hypertension. There are few reports concerning the effects and mechanisms of green tea supplementation preventing age related hypertension. The current study investigated the effect and mechanism of dietary supplement of Huangshan Maofeng green tea (HSMF) on prevention of hypertension induced by deoxycorticosterone acetate (DOCA) and salt in old C57BL/6 mice. Our results showed that HSMF dose-dependently prevented the increase of systolic blood pressure and diastolic blood pressure induced by DOCA plus salt (DS) at 51-week-old mice. And HSMF significantly reduced the agonists' stimulated contraction of mesenteric arteries isolated from the old mice. The expression of vasoconstrictor genes and inflammatory cytokines in aorta were suppressed observably by HSMF supplementation compared with DS group. The protein expression of PKCα in the aorta was dose-dependently decreased by HSMF compared to DS group. The phosphorylation level of MYPT1, CPI-17and MLC20 was also restrained by HSMF in the aorta. Furthermore, HSMF protected kidney by maintaining integrity of glomeruli and tubules and remarkably decreased the NGAL level in plasma. HSMF also suppressed the kidney inflammation by decreasing inflammatory cytokines expression and the macrophage infiltration. Our results proved that dietary supplement of HSMF remarkably improved the vascular functions and protected kidney injury, and thus prevented hypertension induced by DS in older C57BL/6 mice. Our data indicated that the dietary supplement of HSMF may potentially be used as a food additive for preventing hypertension for aged people.

[Mineralcorticoid receptor blockers in chronic kidney disease]

There are many experimental data supporting the involvement of aldosterone and mineralcorticoid receptor (MR) activation in the genesis and progression of chronic kidney disease (CKD) and cardiovascular damage. Many studies have shown that in diabetic and non-diabetic CKD, blocking the renin- angiotensin-aldosterone (RAAS) system with conversion enzyme inhibitors (ACEi) or angiotensin II receptor blockers (ARBs) decreases proteinuria, progression of CKD and mortality, but there is still a significant residual risk of developing these events. In subjects treated with ACEi or ARBs there may be an aldosterone breakthrough whose prevalence in subjects with CKD can reach 50%. Several studies have shown that in CKD, the aldosterone antagonists (spironolactone, eplerenone) added to ACEi or ARBs, reduce proteinuria, but increase the risk of hyperkalemia. Other studies in subjects treated with dialysis suggest a possible beneficial effect of antialdosteronic drugs on CV events and mortality. Newer potassium binders drugs can prevent / decrease hyperkalemia induced by RAAS blockade, and may reduce the high discontinuation rates or dose reduction of RAAS-blockers. The nonsteroidal MR blockers, with more potency and selectivity than the classic ones, reduce proteinuria and have a lower risk of hyperkalemia. Several clinical trials, currently underway, will determine the effect of classic MR blockers on CV events and mortality in subjects with stage 3b CKD and in dialysis patients, and whether in patients with type 2 diabetes mellitus and CKD, optimally treated and with high risk of CV and kidney events, the addition of finerenone to their treatment produces cardiorenal benefits. Large randomized trials have shown that sodium glucose type 2 cotransporter inhibitors (SGLT2i) reduce mortality and the development and progression of diabetic and nondiabetic CKD. There are pathophysiological arguments, which raise the possibility that the triple combination ACEi or ARBs, SGLT2i and aldosterone antagonist provide additional renal and cardiovascular protection.

Targeting the renin-angiotensin signaling pathway in COVID-19: Unanswered questions, opportunities, and challenges

The role of the renin-angiotensin signaling (RAS) pathway in COVID-19 has received much attention. A central mechanism for COVID-19 pathophysiology has been proposed: imbalance of angiotensin converting enzymes (ACE)1 and ACE2 (ACE2 being the severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] virus "receptor") that results in tissue injury from angiotensin II (Ang II)-mediated signaling. This mechanism provides a rationale for multiple therapeutic approaches. In parallel, clinical data from retrospective analysis of COVID-19 cohorts has revealed that ACE inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) may be beneficial in COVID-19. These findings have led to the initiation of clinical trials using approved drugs that target the generation (ACEIs) and actions (ARBs) of Ang II. However, treatment of COVID-19 with ACEIs/ARBs poses several challenges. These include choosing appropriate inclusion and exclusion criteria, dose optimization, risk of adverse effects and drug interactions, and verification of target engagement. Other approaches related to the RAS pathway might be considered, for example, inhalational administration of ACEIs/ARBs (to deliver drugs directly to the lungs) and use of compounds with other actions (e.g., activation of ACE2, agonism of MAS1 receptors, β-arrestin-based Angiotensin receptor agonists, and administration of soluble ACE2 or ACE2 peptides). Studies with animal models could test such approaches and assess therapeutic benefit. This Perspective highlights questions whose answers could advance RAS-targeting agents as mechanism-driven ways to blunt tissue injury, morbidity, and mortality of COVID-19.

Finerenone and Cardiovascular Outcomes in Patients With Chronic Kidney Disease and Type 2 Diabetes

Supplemental Digital Content is available in the text.

Background:

The FIDELIO-DKD trial (Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease) evaluated the effect of the nonsteroidal, selective mineralocorticoid receptor antagonist finerenone on kidney and cardiovascular outcomes in patients with chronic kidney disease and type 2 diabetes with optimized renin–angiotensin system blockade. Compared with placebo, finerenone reduced the composite kidney and cardiovascular outcomes. We report the effect of finerenone on individual cardiovascular outcomes and in patients with and without history of atherosclerotic cardiovascular disease (CVD).

Methods:

This randomized, double-blind, placebo-controlled trial included patients with type 2 diabetes and urine albumin-to-creatinine ratio 30 to 5000 mg/g and an estimated glomerular filtration rate ≥25 to <75 mL per min per 1.73 m², treated with optimized renin–angiotensin system blockade. Patients with a history of heart failure with reduced ejection fraction were excluded. Patients were randomized 1:1 to receive finerenone or placebo. The composite cardiovascular outcome included time to cardiovascular death, myocardial infarction, stroke, or hospitalization for heart failure. Prespecified cardiovascular analyses included analyses of the components of this composite and outcomes according to CVD history at baseline.

Results:

Between September 2015 and June 2018, 13 911 patients were screened and 5674 were randomized; 45.9% of patients had CVD at baseline. Over a median follow-up of 2.6 years (interquartile range, 2.0–3.4 years), finerenone reduced the risk of the composite cardiovascular outcome compared with placebo (hazard ratio, 0.86 [95% CI, 0.75–0.99]; P=0.034), with no significant interaction between patients with and without CVD (hazard ratio, 0.85 [95% CI, 0.71–1.01] in patients with a history of CVD; hazard ratio, 0.86 [95% CI, 0.68–1.08] in patients without a history of CVD; P value for interaction, 0.85). The incidence of treatment-emergent adverse events was similar between treatment arms, with a low incidence of hyperkalemia-related permanent treatment discontinuation (2.3% with finerenone versus 0.8% with placebo in patients with CVD and 2.2% with finerenone versus 1.0% with placebo in patients without CVD).

Conclusions:

Among patients with chronic kidney disease and type 2 diabetes, finerenone reduced incidence of the composite cardiovascular outcome, with no evidence of differences in treatment effect based on preexisting CVD status.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02540993.

Role of the vascular endothelial sodium channel activation in the genesis of pathologically increased cardiovascular stiffness

Cardiovascular (CV) stiffening represents a complex series of events evolving from pathological changes in individual cells of the vasculature and heart which leads to overt tissue fibrosis. While vascular stiffening occurs naturally with ageing it is accelerated in states of insulin (INS) resistance, such as obesity and type 2 diabetes. CV stiffening is clinically manifested as increased arterial pulse wave velocity and myocardial fibrosis-induced diastolic dysfunction. A key question that remains is how are these events mechanistically linked. In this regard, heightened activation of vascular mineralocorticoid receptors (MR) and hyperinsulinaemia occur in obesity and INS resistance states. Further, a downstream mediator of MR and INS receptor activation, the endothelial cell Na+ channel (EnNaC), has recently been identified as a key molecular determinant of endothelial dysfunction and CV fibrosis and stiffening. Increased activity of the EnNaC results in a number of negative consequences including stiffening of the cortical actin cytoskeleton in endothelial cells, impaired endothelial NO release, increased oxidative stress-meditated NO destruction, increased vascular permeability, and stimulation of an inflammatory environment. Such endothelial alterations impact vascular function and stiffening through regulation of vascular tone and stimulation of tissue remodelling including fibrosis. In the case of the heart, obesity and INS resistance are associated with coronary vascular endothelial stiffening and associated reductions in bioavailable NO leading to heart failure with preserved systolic function (HFpEF). After a brief discussion on mechanisms leading to vascular stiffness per se, this review then focuses on recent findings regarding the role of INS and aldosterone to enhance EnNaC activity and associated CV stiffness in obesity/INS resistance states. Finally, we discuss how coronary artery-mediated EnNaC activation may lead to cardiac fibrosis and HFpEF, a condition that is especially pronounced in obese and diabetic females.

Impact of the Renin-Angiotensin System on the Endothelium in Vascular Dementia: Unresolved Issues and Future Perspectives

The effects of the renin-angiotensin system (RAS) surpass the renal and cardiovascular systems to encompass other body tissues and organs, including the brain. Angiotensin II (Ang II), the most potent mediator of RAS in the brain, contributes to vascular dementia via different mechanisms, including neuronal homeostasis disruption, vascular remodeling, and endothelial dysfunction caused by increased inflammation and oxidative stress. Other RAS components of emerging significance at the level of the blood-brain barrier include angiotensin-converting enzyme 2 (ACE2), Ang(1-7), and the AT2, Mas, and AT4 receptors. The various angiotensin hormones perform complex actions on brain endothelial cells and pericytes through specific receptors that have either detrimental or beneficial actions. Increasing evidence indicates that the ACE2/Ang(1-7)/Mas axis constitutes a protective arm of RAS on the blood-brain barrier. This review provides an update of studies assessing the different effects of angiotensins on cerebral endothelial cells. The involved signaling pathways are presented and help highlight the potential pharmacological targets for the management of cognitive and behavioral dysfunctions associated with vascular dementia.

Obesity and cardiovascular disease in women

As the prevalence of obesity continues to grow worldwide, the health and financial burden of obesity-related comorbidities grows too. Cardiovascular disease (CVD) is clearly associated with increased adiposity. Importantly, women are at higher risk of CVD when obese and insulin resistant, in particular at higher risk of developing heart failure with preserved ejection fraction and ischemic heart disease. Increased aldosterone and mineralocorticoid receptor activation, aberrant estrogenic signaling and elevated levels of androgens are among some of the proposed mechanisms explaining the heightened CVD risk. In addition to traditional cardiovascular risk factors, understanding nontraditional risk factors specific to women, like excess weight gain during pregnancy, preeclampsia, gestational diabetes, and menopause are central to designing personalized interventions aimed to curb the epidemic of CVD. In the present review, we examine the available evidence supporting a differential cardiovascular impact of increased adiposity in women compared with men and the proposed pathophysiological mechanisms behind these differences. We also discuss women-specific cardiovascular risk factors associated with obesity and insulin resistance.

Rethinking furosemide use for infants with bronchopulmonary dysplasia

Diuretics are commonly administered to infants with bronchopulmonary dysplasia (BPD) to improve respiratory function despite the absence of prospective data demonstrating long term benefits. While many potentially adverse effects of furosemide are known to clinicians, its direct and indirect impact on multiple pathophysiological processes need to be understood. While furosemide likely has a role in the management of infants with BPD, clinicians are encouraged to recognize these potential complications associated with furosemide administration. Specifically, a deeper understanding of the impact of diuretics on sodium metabolism neurohumoral regulation of cardiopulmonary physiology is required.

Steroid hormone secretion after stimulation of mineralocorticoid and NMDA receptors and cardiovascular risk in patients with depression

Major depressive disorder (MDD) is associated with altered mineralocorticoid receptor (MR) and glucocorticoid receptor function, and disturbed glutamatergic signaling. Both systems are closely intertwined and likely contribute not only to the pathophysiology of MDD, but also to the increased cardiovascular risk in MDD patients. Less is known about other steroid hormones, such as aldosterone and DHEA-S, and how they affect the glutamatergic system and cardiovascular disease risk in MDD. We examined salivary cortisol, aldosterone, and DHEA-S secretion after stimulation of MR and glutamatergic NMDA receptors in 116 unmedicated depressed patients, and 116 age- and sex-matched healthy controls. Patients (mean age = 34.7 years, SD = ±13.3; 78% women) and controls were randomized to four conditions: (a) control condition (placebo), (b) MR stimulation (0.4 mg fludrocortisone), (c) NMDA stimulation (250 mg D-cycloserine (DCS)), and (d) combined MR/NMDA stimulation (fludrocortisone + DCS). We additionally determined the cardiovascular risk profile in both groups. DCS had no effect on steroid hormone secretion, while cortisol secretion decreased in both fludrocortisone conditions across groups. Independent of condition, MDD patients showed (1) increased cortisol, increased aldosterone, and decreased DHEA-S concentrations, and (2) increased glucose levels and decreased high-density lipoprotein cholesterol levels compared with controls. Depressed patients show profound alterations in several steroid hormone systems that are associated both with MDD pathophysiology and increased cardiovascular risk. Prospective studies should examine whether modulating steroid hormone levels might reduce psychopathology and cardiovascular risk in depressed patients.

Progesterone: An enigmatic ligand for the mineralocorticoid receptor

The progesterone receptor (PR) mediates progesterone regulation of female reproductive physiology, as well as gene transcription in non-reproductive tissues, such as brain, bone, lung and vasculature, in both women and men. An unusual property of progesterone is its high affinity for the mineralocorticoid receptor (MR), which regulates electrolyte transport in the kidney in humans and other terrestrial vertebrates. In humans, rats, alligators and frogs, progesterone antagonizes activation of the MR by aldosterone, the physiological mineralocorticoid in terrestrial vertebrates. In contrast, in elephant shark, ray-finned fishes and chickens, progesterone activates the MR. Interestingly, cartilaginous fishes and ray-finned fishes do not synthesize aldosterone, raising the question of which steroid(s) activate the MR in cartilaginous fishes and ray-finned fishes. The simpler synthesis of progesterone, compared to cortisol and other corticosteroids, makes progesterone a candidate physiological activator of the MR in elephant sharks and ray-finned fishes. Elephant shark and ray-finned fish MRs are expressed in diverse tissues, including heart, brain and lung, as well as, ovary and testis, two reproductive tissues that are targets for progesterone, which together suggests a multi-faceted physiological role for progesterone activation of the MR in elephant shark and ray-finned fish. The functional consequences of progesterone as an antagonist of some terrestrial vertebrate MRs and as an agonist of fish and chicken MRs are not fully understood. The physiological activities of progesterone through binding to vertebrate MRs merits further investigation.

Regulation of ion channels in the microcirculation by mineralocorticoid receptor activation

The mineralocorticoid receptor (MR) has classically been studied in the renal epithelium for its role in regulating sodium and water balance and, subsequently, blood pressure. However, the MR also plays a critical role in the microvasculature by regulating ion channel expression and function. Activation of the MR by its endogenous agonist aldosterone results in translocation of the MR into the nucleus, where it can act as a transcription factor. Although most of the actions of the aldosterone can be attributed to its genomic activity though MR activation, it can also act by nongenomic mechanisms. Activation of this ubiquitous receptor increases the expression of epithelial sodium channels (ENaC) in both the endothelium and smooth muscle cells of peripheral and cerebral vessels. MR activation also regulates activity of calcium channels, calcium-activated potassium channels, and various transient receptor potential (TRP) channels. Modification of these ion channels results in a myriad of negative consequences, including impaired endothelium-dependent vasodilation, alterations in generation of myogenic tone, and increased inflammation and oxidative stress. Taken together, these studies demonstrate the importance of studying the impact of the MR on ion channel function in the vasculature. While research in this area has made advances in recent years, there are still many large gaps in knowledge that need to be filled. Crucial future directions of study include defining the molecular mechanisms involved in this interaction, as well as elucidating the potential sex differences that may exist, as these areas of understanding are currently lacking.