Functional mineralocorticoid receptors in human vascular endothelial cells regulate intercellular adhesion molecule-1 expression and promote leukocyte adhesion

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.

Preoperative activation of the renin-angiotensin system and myocardial injury in noncardiac surgery: exploratory mechanistic analysis of the SPACE randomised controlled trial

BACKGROUND

Hypertension therapy in older adults is often suboptimal, in part because of inadequate suppression of the renin-angiotensin-aldosterone system (RAAS). We hypothesised that distinct endotypes of RAAS activation before noncardiac surgery are associated with increased risk of myocardial injury.

METHODS

This was a prespecified exploratory analysis of a multicentre randomised controlled trial (ISRCTN17251494) which randomised patients ≥60 yr old undergoing elective noncardiac surgery to either continue or stop RAAS inhibitors (determined by pharmacokinetic profiles). Unsupervised hierarchical cluster analysis identified distinct groups of patients with similar RAAS activation from samples obtained before induction of anaesthesia, quantified by enzyme-linked immunoassays for plasma renin, aldosterone, angiotensin-converting enzyme 2, and dipeptidyl peptidase-3. The primary outcome, masked to investigators and participants, was myocardial injury (plasma high-sensitivity troponin-T).

RESULTS

We identified three clusters, with similar proportions of RAAS inhibitors randomised to stop or continue. Cluster 1 (n=52; mean age [standard deviation], 75 yr [8 yr]; 54% female) and cluster 3 (n=25; 75 yr [6 yr]; 44% female) had higher rates of myocardial injury (23/52 [44%] and 13/25 [52%], respectively), compared with cluster 2 with 51/164 (31.1%; n=153; 70 yr [6] yr; 46% female; odds ratio: 1.95, 95% confidence interval (CI) 1.12-3.39, P=0.018). Cluster 2 was characterised by lower N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration (mean difference 698 pg ml-1, 95% CI 576-820 pg ml-1) and higher renin concentration (mean difference 350 pg ml-1, 95% CI 123-577 pg ml-1), compared with clusters 1 and 3 which had higher rates of myocardial injury.

CONCLUSIONS

This mechanistic exploratory analysis suggests that effective preoperative RAAS inhibition is associated with lower risk of myocardial injury after noncardiac surgery, independent of stopping or continuing RAAS inhibitors before surgery.

CLINICAL TRIAL REGISTRATION

ISRCTN17251494.

Microvascular Endothelial Function Assessed Using Peripheral Arterial Tonometry in Adolescents with Repaired Congenital Heart Disease

Atherosclerosis can develop in adult patients with congenital heart disease (CHD) and should be given attention. Endothelial function is well known as a predictor of the development of atherosclerosis but has not been well investigated in patients with repaired CHD. This study aimed to clarify the endothelial function and its relationship with clinical backgrounds and parameters in adolescents with various types of repaired CHDs. Endothelial function was evaluated using peripheral arterial tonometry (PAT). The reactive hyperemia index (RHI) was evaluated and compared between adolescents with repaired CHD and those in the control group. The relationship between the clinical background and parameters was also investigated in patients with repaired CHD. Forty-eight patients with repaired CHD (age 14.0 ± 3.3 years) and 114 healthy volunteers were included in this study. Patients with repaired CHD comprised 16 with repaired non-cyanotic CHD, 14 with repaired tetralogy of Fallot, and 18 who underwent the Fontan procedure. RHI in the repaired CHD group was significantly lower than in the control group. There was no significant correlation between the RHI and blood biochemical markers, such as uric acid, creatine, and brain natriuretic peptide levels. The RHI was significantly higher in patients taking angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) than in those not taking them. Endothelial function was impaired in adolescents with repaired CHD compared to that in the control group. Microvascular endothelial dysfunction developed even in adolescents with simple non-cyanotic CHD.

Glaucoma and the ocular renin-angiotensin-aldosterone system: Update on molecular signalling and treatment perspectives

Glaucoma, a leading cause of blindness worldwide, encompasses a group of pathological conditions affecting the optic nerve and is characterized by progressive retinal ganglion cell loss, cupping of the optic nerve head, and distinct visual field defects. While elevated intraocular pressure (IOP) is the main risk factor for glaucoma, many patients do not have elevated IOP. Consequently, other risk factors, such as ocular blood flow abnormalities and immunological factors, have been implicated in its pathophysiology. Traditional therapeutic strategies primarily aim to reduce IOP, but there is growing interest in developing novel treatment approaches to improve disease management and reduce the high rates of severe visual impairment. In this context, targeting the ocular renin-angiotensin-aldosterone system (RAAS) has been found as a potential curative strategy. The RAAS contributes to glaucoma development through key effectors such as prorenin, angiotensin II, and aldosterone. Recent evidence has highlighted the potential of using RAAS modulators to combat glaucoma, yielding encouraging results. Our study aims to explore the molecular pathways linking the ocular RAAS and glaucoma, summarizing recent advances that elucidate the role of the RAAS in triggering oxidative stress, inflammation, and remodelling in the pathogenesis of glaucoma. Additionally, we will present emerging therapeutic approaches that utilize RAAS modulators and antioxidants to slow the progression of glaucoma.

The mineralocorticoid receptor in diabetic kidney disease

Diabetes mellitus is one of the leading causes of chronic kidney disease and its progression to end-stage kidney disease (ESKD). Diabetic kidney disease (DKD) is characterized by glomerular hypertrophy, hyperfiltration, inflammation, and the onset of albuminuria, together with a progressive reduction in glomerular filtration rate. This progression is further accompanied by tubulointerstitial inflammation and fibrosis. Factors such as genetic predisposition, epigenetic modifications, metabolic derangements, hemodynamic alterations, inflammation, and inappropriate renin-angiotensin-aldosterone system (RAAS) activity contribute to the onset and progression of DKD. In this context, decades of work have focused on glycemic and blood pressure reduction strategies, especially targeting the RAAS to slow disease progression. Although much of the work has focused on targeting angiotensin II, emerging data support that the mineralocorticoid receptor (MR) is integral in the development and progression of DKD. Molecular mechanisms linked to the underlying pathophysiological changes derived from MR activation include vascular endothelial and epithelial cell responses to oxidative stress and inflammation. These responses lead to alterations in the microcirculatory environment, the abnormal release of extracellular vesicles, gut dysbiosis, epithelial-mesenchymal transition, and kidney fibrosis. Herein, we present recent experimental and clinical evidence on the MR in DKD onset and progress along with new MR-based strategies for the treatment and prevention of DKD.

The role of cardiac microenvironment in cardiovascular diseases: implications for therapy

Due to aging populations and changes in lifestyle, cardiovascular diseases including cardiomyopathy, hypertension, and atherosclerosis, are the leading causes of death worldwide. The heart is a complicated organ composed of multicellular types, including cardiomyocytes, fibroblasts, endothelial cells, vascular smooth muscle cells, and immune cells. Cellular specialization and complex interplay between different cell types are crucial for the cardiac tissue homeostasis and coordinated function of the heart. Mounting studies have demonstrated that dysfunctional cells and disordered cardiac microenvironment are closely associated with the pathogenesis of various cardiovascular diseases. In this paper, we discuss the composition and the homeostasis of cardiac tissues, and focus on the role of cardiac environment and underlying molecular mechanisms in various cardiovascular diseases. Besides, we elucidate the novel treatment for cardiovascular diseases, including stem cell therapy and targeted therapy. Clarification of these issues may provide novel insights into the prevention and potential targets for cardiovascular diseases.

Effects of the mineralocorticoid receptor antagonist eplerenone in experimental autoimmune encephalomyelitis

There is growing evidence indicating that mineralocorticoid receptor (MR) expression influences a wide variety of functions in metabolic and immune response. The present study explored if antagonism of the MR reduces neuroinflammation in the spinal cord of mice with experimental autoimmune encephalomyelitis (EAE). Eplerenone (EPLE) (100 mg/kg dissolved in 30% 2-hydroxypropyl-β-cyclodextrin) was administered intraperitoneally (i.p.) daily from EAE induction (day 0) until sacrificed on day 17 post-induction. The MR blocker (a) significantly decreased the inflammatory parameters TLR4, MYD88, IL-1β, and iNOS mRNAs; (b) attenuated HMGB1, NLRP3, TGF-β mRNAs, microglia, and aquaporin4 immunoreaction without modifying GFAP. Serum IL-1β was also decreased in the EAE+EPLE group. Moreover, EPLE treatment prevented demyelination and improved clinical signs of EAE mice. Interestingly, MR was decreased and GR remained unchanged in EAE mice while EPLE treatment restored MR expression, suggesting that a dysbalanced MR/GR was associated with the development of neuroinflammation. Our results indicated that MR blockage with EPLE attenuated inflammation-related spinal cord pathology in the EAE mouse model of Multiple Sclerosis, supporting a novel therapeutic approach for immune-related diseases.

BAP31 Promotes Adhesion Between Endothelial Cells and Macrophages Through the NF-κB Signaling Pathway in Sepsis

Purpose

To investigate the role of B cell receptor associated protein 31 (BAP31) in the pathogenesis of sepsis.

Methods

Cecal ligation and puncture (CLP)-induced C57BL/6J mice, and LPS-challenged endothelial cells (HUVECs) were established to mimic a sepsis animal model and a sepsis cell model, respectively. Cre/LoxP and shRNA methods were used for BAP31 knockdown in vivo and in vitro respectively. Neutrophils/macrophages-endothelial cocultures were used to evaluate neutrophils or macrophages infiltration and adhesion to endothelial cells. Cox proportional hazards model was used to evaluate the survival time of mice. Western blotting (WB) and Quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect toll-like receptor (TLR) signaling pathway, transforming growth factor β activated kinase 1 (TAK1) signaling pathway and phosphoinositide-3 kinases-protein kinase B (PI3K/AKT) signaling pathway.

Results

Deletion of BAP31 reduced CLP-induced mortality of mice, histological damage with less interstitial edema, and neutrophils and macrophages infiltration. IHC and IF showed that BAP31 knockdown significantly decreases the expressions of ICAM1 and VCAM1 both in vivo and in vitro. Coculture showed that LPS-induced neutrophils or macrophages adhesion to endothelial cells was significantly weakened in BAP31 knockdown cells. In addition, BAP31 knockdown of endothelial cells decreased the expression of CD80 and CD86 on the surface of macrophages as well as interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) during sepsis. Mechanistically, LPS-induced the activation of TLR4, MyD88 and TRAF6, and the phosphorylation of TAK1, PI3K, AKT, IκBα and IKKα/β, resulting in activation of nuclear factor kappa B (NF-κB) p65 in endothelial cells. However, BAP31 knockdown significantly reversed the expressions of associated proteins.

Conclusion

BAP31 up-regulated the expressions of ICAM1 and VCAM1 in endothelial cells leading to sepsis-associated organ injury. This may be involved in activation of TLR signaling pathway, TAK1 pathway, and PI3K-AKT signaling pathway.

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).

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

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

First Evidence of Mineralocorticoid Receptor Gene and Protein Expression in Rat and Human Thyroid Tissues and Cell Cultures

Aldosterone (Aldo) exerts its action through binding with the mineralocorticoid receptor (MR). Clinically, a link between primary aldosteronism (PA) and thyroid diseases has been hypothesised. However, the presence and activity of MR on the thyroid have not yet been demonstrated. We investigated the gene/protein expression and activation of MR in primary thyroid cell cultures (normal rat thyroid [FRTL-5] and human papillary thyroid cancer [PTC] cell lines, BCPAP and K1) through qRT-PCR analysis, immunofluorescence, and confocal microscopy. We also studied the effects of Aldo on thyroid-specific and inflammation genes in vitro. Paired human normal and neoplastic thyroid tissues were also studied. We demonstrated both gene and protein expression and activation of MR in normal rat thyroid and human PTC lines. Incubation with Aldo induced an acute increase in IL-6 expression in both the FRTL-5 and BCPAP lines, which was antagonised by spironolactone, and an acute and late upregulation of thyroid-specific genes in FRTL-5. MR was also expressed at both gene and protein levels in normal human thyroid tissues and in PTC, with a progressive decline during neoplastic tumourigenesis, particularly in more aggressive histotypes. We present the first evidence of MR gene and protein expression in both normal and pathological thyroid cells and tissues. We have shown that MR is present and functionally activated in thyroid tissue. Binding of Aldo to MR induces the expression of inflammatory and thyroid-specific genes, and the thyroid may thus be considered a novel mineralocorticoid target tissue.

Biomarkers to Guide Medical Therapy in Primary Aldosteronism

Primary aldosteronism (PA) is an endocrinopathy characterized by dysregulated aldosterone production that occurs despite suppression of renin and angiotensin II, and that is non-suppressible by volume and sodium loading. The effectiveness of surgical adrenalectomy for patients with lateralizing PA is characterized by the attenuation of excess aldosterone production leading to blood pressure reduction, correction of hypokalemia, and increases in renin-biomarkers that collectively indicate a reversal of PA pathophysiology and restoration of normal physiology. Even though the vast majority of patients with PA will ultimately be treated medically rather than surgically, there is a lack of guidance on how to optimize medical therapy and on key metrics of success. Herein, we review the evidence justifying approaches to medical management of PA and biomarkers that reflect endocrine principles of restoring normal physiology. We review the current arsenal of medical therapies, including dietary sodium restriction, steroidal and nonsteroidal mineralocorticoid receptor antagonists, epithelial sodium channel inhibitors, and aldosterone synthase inhibitors. It is crucial that clinicians recognize that multimodal medical treatment for PA can be highly effective at reducing the risk for adverse cardiovascular and kidney outcomes when titrated with intention. The key biomarkers reflective of optimized medical therapy are unsurprisingly similar to the physiologic expectations following surgical adrenalectomy: control of blood pressure with the fewest number of antihypertensive agents, normalization of serum potassium without supplementation, and a rise in renin. Pragmatic approaches to achieve these objectives while mitigating adverse effects are reviewed.

The association of aldosterone with papillophlebitis and retinal artery occlusion: A case report

PURPOSE

To explore the association between elevated blood aldosterone levels and papillophlebitis and retinal artery occlusion in a young, healthy woman.

CASE DESCRIPTION

A 19-year-old woman with an unremarkable medical history presented with sudden-onset visual loss in the right eye, which lasted for 10 hours. Fundus examination revealed retinal whitening, splinter hemorrhages, disc swelling, and tortuous vessels in the right eye. Optical coherence tomography revealed inner retinal thickening. Fluorescein angiography demonstrated a delayed arteriovenous transit time and delayed filling of the cilioretinal artery circulation. Further workup showed a high aldosterone level and aldosterone-to-renin ratio. The patient was treated with steroid pulse therapy and combined intravitreal injection of dexamethasone implant and aflibercept. Visual acuity was recovered from count finger at initial presentation to 6/15 on the fifth day. For over 2 months, the fundal manifestations gradually subsided. Three months after the episode, her visual acuity further improved to 6/6.7.

CONCLUSION

This report emphasizes the potential role aldosterone plays in the complex disease mechanism of retinal vasculopathy. In addition, steroid pulse therapy is more effective when applied in conjunction with combined intravitreal injection therapy for rescuing impaired vision caused by retinal vascular occlusion.

Impact of Immunity on Coronary Artery Disease: An Updated Pathogenic Interplay and Potential Therapeutic Strategies

Coronary artery disease (CAD) is the leading cause of death worldwide. It is a result of the buildup of atherosclerosis within the coronary arteries. The role of the immune system in CAD is complex and multifaceted. The immune system responds to damage or injury to the arterial walls by initiating an inflammatory response. However, this inflammatory response can become chronic and lead to plaque formation. Neutrophiles, macrophages, B lymphocytes, T lymphocytes, and NKT cells play a key role in immunity response, both with proatherogenic and antiatherogenic signaling pathways. Recent findings provide new roles and activities referring to endothelial cells and vascular smooth muscle cells, which help to clarify the intricate signaling crosstalk between the involved actors. Research is ongoing to explore immunomodulatory therapies that target the immune system to reduce inflammation and its contribution to atherosclerosis. This review aims to summarize the pathogenic interplay between immunity and CAD and the potential therapeutic strategies, and explore immunomodulatory therapies that target the immune system to reduce inflammation and its contribution to atherosclerosis.

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.

Aldosterone: Essential for Life but Damaging to the Vascular Endothelium

The renin angiotensin aldosterone system is a key regulator of blood pressure. Aldosterone is the final effector of this pathway, acting predominantly via mineralocorticoid receptors. Aldosterone facilitates the conservation of sodium and, with it, water and acts as a powerful stimulus for potassium excretion. However, evidence for the pathological impact of excess mineralocorticoid receptor stimulation is increasing. Here, we discussed how in the heart, hyperaldosteronism is associated with fibrosis, cardiac dysfunction, and maladaptive hypertrophy. In the kidney, aldosterone was shown to cause proteinuria and fibrosis and may contribute to the progression of kidney disease. More recently, studies suggested that aldosterone excess damaged endothelial cells. Here, we reviewed how damage to the endothelial glycocalyx may contribute to this process. The endothelial glycocalyx is a heterogenous, negatively charged layer on the luminal surface of cells. Aldosterone exposure alters this layer. The resulting structural changes reduced endothelial reactivity in response to protective shear stress, altered permeability, and increased immune cell trafficking. Finally, we reviewed current therapeutic strategies for limiting endothelial damage and suggested that preventing glycocalyx remodelling in response to aldosterone exposure may provide a novel strategy, free from the serious adverse effect of hyperkalaemia seen in response to mineralocorticoid blockade.

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.

Association of Aldosterone with Mortality in the General Population

INTRODUCTION

Aldosterone excess is linked to cardiovascular events and mortality as well as to low-grade inflammation in the context of metabolic diseases. Whether mildly elevated aldosterone levels in the general population promote cardiovascular risk is still under debate. We analyzed the association of plasma aldosterone concentrations with incident cardiovascular events, cardiovascular and all-cause mortality as well as with biomarkers of subclinical inflammation in the population-based KORA F4 study.

METHODS

Plasma aldosterone concentrations were measured with an in-house immunoflurometric assay. The analyses included 2935 participants (n=1076 for selected biomarkers of subclinical inflammation) with a median follow-up of 8.7 (8.2; 9.1) years. The associations were estimated using Cox proportional hazard and linear regression models adjusted for renin, sex, age, body mass index, arterial hypertension, diabetes, estimated glomerular filtration rate, low- and high-density lipoprotein cholesterol, physical activity, smoking, use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, diuretics and calcium channel blockers.

RESULTS

Aldosterone was significantly associated with all-cause mortality (hazard ratio per standard deviation increase: 1.20; 95% confidence interval 1.04-1.37), but not with cardiovascular mortality, incident cardiovascular events, or with biomarkers of subclinical inflammation.

CONCLUSIONS

Aldosterone was associated with all-cause mortality in the population-based KORA F4 study, but the previously described associations of excess aldosterone with cardiovascular complications and biomarkers of subclinical inflammation could not be shown.

Aldosterone and cardiovascular diseases

Aldosterone's role in the kidney and its pathophysiologic actions in hypertension are well known. However, its role or that of its receptor [minieralocorticoid receptor (MR)] in other cardiovascular (CV) disease are less well described. To identify their potential roles in six CV conditions (heart failure, myocardial infarction, atrial fibrillation, stroke, atherosclerosis, and thrombosis), we assessed these associations in the following four areas: (i) mechanistic studies in rodents and humans; (ii) pre-clinical studies of MR antagonists; (iii) clinical trials of MR antagonists; and (iv) genetics. The data were acquired from an online search of the National Library of Medicine using the PubMed search engine from January 2011 through June 2021. There were 3702 publications identified with 200 publications meeting our inclusion and exclusion criteria. Data strongly supported an association between heart failure and dysregulated aldosterone/MR. This association is not surprising given aldosterone/MR's prominent role in regulating sodium/volume homeostasis. Atrial fibrillation and myocardial infarction are also associated with dysregulated aldosterone/MR, but less strongly. For the most part, the data were insufficient to determine whether there was a relationship between atherosclerosis, stroke, or thrombosis and aldosterone/MR dysregulation. This review clearly documented an expanding role for aldosterone/MR's dysregulation in CV diseases beyond hypertension. How expansive it might be is limited by the currently available data. It is anticipated that with an increased focus on aldosterone/MR's potential roles in these diseases, additional clinical and pre-clinical data will clarify these relationships, thereby, opening approaches to use modulators of aldosterone/MR's action to more precisely treat these CV conditions.

Mineralocorticoid receptor antagonism in diabetes reduces albuminuria by preserving the glomerular endothelial glycocalyx

The glomerular endothelial glycocalyx (GEnGlx) forms the first part of the glomerular filtration barrier. Previously, we showed that mineralocorticoid receptor (MR) activation caused GEnGlx damage and albuminuria. In this study, we investigated whether MR antagonism could limit albuminuria in diabetes and studied the site of action. Streptozotocin-induced diabetic Wistar rats developed albuminuria, increased glomerular albumin permeability (Ps'alb), and increased glomerular matrix metalloproteinase (MMP) activity with corresponding GEnGlx loss. MR antagonism prevented albuminuria progression, restored Ps'alb, preserved GEnGlx, and reduced MMP activity. Enzymatic degradation of the GEnGlx negated the benefits of MR antagonism, confirming their dependence on GEnGlx integrity. Exposing human glomerular endothelial cells (GEnC) to diabetic conditions in vitro increased MMPs and caused glycocalyx damage. Amelioration of these effects confirmed a direct effect of MR antagonism on GEnC. To confirm relevance to human disease, we used a potentially novel confocal imaging method to show loss of GEnGlx in renal biopsy specimens from patients with diabetic nephropathy (DN). In addition, patients with DN randomized to receive an MR antagonist had reduced urinary MMP2 activity and albuminuria compared with placebo and baseline levels. Taken together, our work suggests that MR antagonists reduce MMP activity and thereby preserve GEnGlx, resulting in reduced glomerular permeability and albuminuria in diabetes.

Mineralocorticoid receptor antagonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease

Diabetic kidney disease (DKD) develops in ∼40% of patients with diabetes and is the most common cause of chronic kidney disease (CKD) worldwide. Patients with CKD, especially those with diabetes mellitus, are at high risk of both developing kidney failure and cardiovascular (CV) death. The use of renin-angiotensin system (RAS) blockers to reduce the incidence of kidney failure in patients with DKD dates back to studies that are now ≥20 years old. During the last few years, sodium-glucose co-transporter-2 inhibitors (SGLT2is) have shown beneficial renal effects in randomized trials. However, even in response to combined treatment with RAS blockers and SGLT2is, the renal residual risk remains high with kidney failure only deferred, but not avoided. The risk of CV death also remains high even with optimal current treatment. Steroidal mineralocorticoid receptor antagonists (MRAs) reduce albuminuria and surrogate markers of CV disease in patients already on optimal therapy. However, their use has been curtailed by the significant risk of hyperkalaemia. In the FInerenone in reducing kiDnEy faiLure and dIsease prOgression in DKD (FIDELIO-DKD) study comparing the actions of the non-steroidal MRA finerenone with placebo, finerenone reduced the progression of DKD and the incidence of CV events, with a relatively safe adverse event profile. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of MRAs, analyses the potential mechanisms involved and discusses their potential future place in the treatment of patients with diabetic CKD.

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.

Structure-function relationships of the aldosterone receptor

The cellular response to the adrenal steroid aldosterone is mediated by the mineralocorticoid receptor (MR), a member of the nuclear receptor superfamily of ligand-dependent transcription factors. The MR binds more than one physiological ligand with binding at the MR determined by pre-receptor metabolism of glucocorticoid ligands by 11β hydroxysteroid dehydrogenase type 2. The MR has a wide tissue distribution with multiple roles beyond the classical role in electrolyte homeostasis including cardiovascular function, immune cell signaling, neuronal fate and adipocyte differentiation. The MR has three principal functional domains, an N-terminal ligand domain, a central DNA binding domain and a C-terminal, ligand binding domain, with structures having been determined for the latter two domains but not for the whole receptor. MR signal-transduction can be best viewed as a series of interactions which are determined by the conformation conferred on the receptor by ligand binding. This conformation then determines subsequent intra- and inter-molecular interactions. These interactions include chromatin, coregulators and other transcription factors, and additional less well characterized cytoplasmic non-genomic effects via crosstalk with other signaling pathways. This chapter will provide a review of MR structure and function, and an analysis of the critical interactions involved in MR-mediated signal transduction, which contribute to ligand- and tissue-specificity. Understanding the relevant mechanisms for selective MR signaling in terms of these interactions opens the possibility of novel therapeutic approaches for the treatment of MR-mediated diseases.

Circadian rhythms of risk factors and management in atherosclerotic and hypertensive vascular disease: Modern chronobiological perspectives of an ancient disease

Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused by vascular endothelial dysfunction, cholesterol deposition, smooth muscle proliferation, inflammatory cell infiltration and connective tissue accumulation. Hypertension is an independent and controllable risk factor for atherosclerotic cardiovascular disease (CVD). Conversely, atherosclerosis hardens the arterial wall and raises arterial blood pressure. Many CVD patients experience both atherosclerosis and hypertension and are prescribed medications to concurrently mitigate the two disease conditions. A substantial number of publications document that many pathophysiological changes caused by atherosclerosis and hypertension occur in a manner dependent upon circadian clocks or clock gene products. This article reviews progress in the research of circadian regulation of vascular cell function, inflammation, hemostasis and atherothrombosis. In particular, it delineates the relationship of circadian organization with signal transduction and activation of the renin-angiotensin-aldosterone system as well as disturbance of the sleep/wake circadian rhythm, as exemplified by shift work, metabolic syndromes and obstructive sleep apnea (OSA), as promoters and mechanisms of atherogenesis and risk for non-fatal and fatal CVD outcomes. This article additionally updates advances in the clinical management of key biological processes of atherosclerosis to optimally achieve suppression of atherogenesis through chronotherapeutic control of atherogenic/hypertensive pathological sequelae.

Mechanism by Which Inflammation and Oxidative Stress Induce Mineralocorticoid Receptor Gene Expression in Aging Vascular Smooth Muscle Cells

BACKGROUND

Vascular MR (mineralocorticoid receptor) expression increases with age driving aging-associated vascular stiffness and hypertension. MR has two isoforms (1α and 1β) with distinct 5'-untranslated and promoter sequences (P1 and P2), but the gene regulatory mechanisms remain unknown. We investigated mechanisms driving MR gene transcriptional regulation in aging human smooth muscle cells (SMC).

METHODS

MR was quantified in aortic tissue and primary human aortic SMC (HASMC) comparing adult and aged donors and adult HASMC treated with H2O2, to induce aging. Predicted transcription factor (TF) binding sites in the MR gene were validated using chromatin immunoprecipitations and reporter assays. The impact of TF inhibitors on MR isoforms and fibrosis target gene expression was examined.

RESULTS

Expression of both MR mRNA isoforms increased with donor age or H2O2 treatment in HASMCs. HIF1α (hypoxia-inducible factor) and the inflammatory TF NFκB (nuclear factor kappa B) both increased with age in HASMCs and are predicted to bind MR promoters. H2O2 induced HIF1α and NFκB expression and DNA binding of HIF1α to the MR P1 promoter and of NFκB to both MR promoters in HASMCs. HIF1α inhibition decreased MR-1α isoform expression while NFκB inhibition decreased both MR isoforms. HIF1α, NFκB, and MR inhibition decreased the expression of a SMC-MR target gene implicated in vascular fibrosis. In human aortic tissues, expression of HIF1α and NFκB each positively correlated with donor age and MR expression (P<0.0001).

CONCLUSIONS

These data implicate the inflammatory TF, NFκB, and oxidative stress-induced TF, HIF1α, in regulating SMC MR transcription in aging HASMCs, which drives aging-related vascular stiffness and cardiovascular disease.

Whole blood methylome-derived features to discriminate endocrine hypertension

Background

Arterial hypertension represents a worldwide health burden and a major risk factor for cardiovascular morbidity and mortality. Hypertension can be primary (primary hypertension, PHT), or secondary to endocrine disorders (endocrine hypertension, EHT), such as Cushing's syndrome (CS), primary aldosteronism (PA), and pheochromocytoma/paraganglioma (PPGL). Diagnosis of EHT is currently based on hormone assays. Efficient detection remains challenging, but is crucial to properly orientate patients for diagnostic confirmation and specific treatment. More accurate biomarkers would help in the diagnostic pathway. We hypothesized that each type of endocrine hypertension could be associated with a specific blood DNA methylation signature, which could be used for disease discrimination. To identify such markers, we aimed at exploring the methylome profiles in a cohort of 255 patients with hypertension, either PHT (n = 42) or EHT (n = 213), and at identifying specific discriminating signatures using machine learning approaches.

Results

Unsupervised classification of samples showed discrimination of PHT from EHT. CS patients clustered separately from all other patients, whereas PA and PPGL showed an overall overlap. Global methylation was decreased in the CS group compared to PHT. Supervised comparison with PHT identified differentially methylated CpG sites for each type of endocrine hypertension, showing a diffuse genomic location. Among the most differentially methylated genes, FKBP5 was identified in the CS group. Using four different machine learning methods—Lasso (Least Absolute Shrinkage and Selection Operator), Logistic Regression, Random Forest, and Support Vector Machine—predictive models for each type of endocrine hypertension were built on training cohorts (80% of samples for each hypertension type) and estimated on validation cohorts (20% of samples for each hypertension type). Balanced accuracies ranged from 0.55 to 0.74 for predicting EHT, 0.85 to 0.95 for predicting CS, 0.66 to 0.88 for predicting PA, and 0.70 to 0.83 for predicting PPGL.

Conclusions

The blood DNA methylome can discriminate endocrine hypertension, with methylation signatures for each type of endocrine disorder.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01347-y.

Lack of NPR1 Increases Vascular Endothelial Adhesion through Induction of Integrin Beta 4

Natriuretic peptide receptor 1 (NPR1) serves as a modulator of vascular endothelial homeostasis. Interactions between monocytes and endothelial cells may initiate endothelium dysfunction, which is known as an early hallmark of atherosclerosis. In this study, we performed RNA-sequencing analysis for the aorta of Npr1 knockout (Npr1^+/−) mice and found that differentially expressed genes were significantly related to cell adhesion. This result was supported by an increased expression of intercellular adhesion molecule 1 (ICAM-1) in the aortic endothelium of Npr1^+/− mice. Moreover, we observed that the knockdown of NPR1 increased ICAM-1 expression and promoted THP-1 monocyte adhesion to human umbilical vein endothelial cells (HUVECs). NPR1 overexpression decreased ICAM-1 expression and inhibited the adhesion of monocytes to HUVECs treated by TNF-α (a cell adhesion inducer). Further analysis showed that adhesion-related genes were enriched in the focal adhesion signaling pathway, in which integrin beta 4 (Itgb4) was determined as a key gene. Notably, ITGB4 expression increased in vascular endothelium of Npr1^+/− mice and in NPR1-knockdown HUVECs. The deficiency of ITGB4 decreased ICAM-1 expression and attenuated monocyte adhesion to NPR1-knockdown endothelial cells. Additionally, a reduced NPR1 and an increased ITGB4 expression level were found in an atherosclerosis mouse model. In conclusion, our findings demonstrate that NPR1 deficiency increases vascular endothelial cell adhesion by stimulating ITGB4 expression, which may contribute to the development of atherosclerosis.

Importance of Micromilieu for Pathophysiologic Mineralocorticoid Receptor Activity-When the Mineralocorticoid Receptor Resides in the Wrong Neighborhood

The mineralocorticoid receptor (MR) is a member of the steroid receptor family and acts as a ligand-dependent transcription factor. In addition to its classical effects on water and electrolyte balance, its involvement in the pathogenesis of cardiovascular and renal diseases has been the subject of research for several years. The molecular basis of the latter has not been fully elucidated, but an isolated increase in the concentration of the MR ligand aldosterone or MR expression does not suffice to explain long-term pathologic actions of the receptor. Several studies suggest that MR activity and signal transduction are modulated by the surrounding microenvironment, which therefore plays an important role in MR pathophysiological effects. Local changes in micromilieu, including hypoxia, ischemia/reperfusion, inflammation, radical stress, and aberrant salt or glucose concentrations affect MR activation and therefore may influence the probability of unphysiological MR actions. The surrounding micromilieu may modulate genomic MR activity either by causing changes in MR expression or MR activity; for example, by inducing posttranslational modifications of the MR or novel interaction with coregulators, DNA-binding sites, or non-classical pathways. This should be considered when developing treatment options and strategies for prevention of MR-associated diseases.

Aldosterone as a Mediator of Cardiovascular Damage

Besides the physiological regulation of water, sodium, and potassium homeostasis, aldosterone modulates several physiological and pathological processes in the cardiovascular system. At the vascular level, aldosterone excess stimulates endothelial dysfunction and infiltration of inflammatory cells, enhances the development of the atherosclerotic plaque, and favors plaque instability, arterial stiffness, and calcification. At the cardiac level, aldosterone increases cardiac inflammation, fibrosis, and myocardial hypertrophy. As a clinical consequence, high aldosterone levels are associated with enhanced risk of cardiovascular events and mortality, especially when aldosterone secretion is inappropriate for renin levels and sodium intake, as in primary aldosteronism. Several clinical trials showed that mineralocorticoid receptor antagonists reduce cardiovascular mortality in patients with heart failure and reduced ejection fraction, but inconclusive results were reported for other cardiovascular conditions, such as heart failure with preserved ejection fraction, myocardial infarction, and atrial fibrillation. In patients with primary aldosteronism, adrenalectomy or treatment with mineralocorticoid receptor antagonists significantly mitigate adverse aldosterone effects, reducing the risk of cardiovascular events, mortality, and incident atrial fibrillation. In this review, we will summarize the major preclinical and clinical studies investigating the cardiovascular damage mediated by aldosterone and the protective effect of mineralocorticoid receptor antagonists for the reduction of cardiovascular risk in patients with cardiovascular diseases and primary aldosteronism.

The Association of Early Corticosteroid Therapy With Clinical and Health-Related Quality of Life Outcomes in Children With Septic Shock

OBJECTIVES

Corticosteroids are commonly used in the treatment of pediatric septic shock without clear evidence of the potential benefits or risks. This study examined the association of early corticosteroid therapy with patient-centered clinically meaningful outcomes.

DESIGN

Subsequent cohort analysis of data derived from the prospective Life After Pediatric Sepsis Evaluation (LAPSE) investigation. Outcomes among patients receiving hydrocortisone or methylprednisolone on study day 0 or 1 were compared with those who did not use a propensity score-weighted analysis that controlled for age, sex, study site, and measures of first-day illness severity.

SETTING

Twelve academic PICUs in the United States.

PATIENTS

Children with community-acquired septic shock 1 month to 18 years old enrolled in LAPSE, 2013-2017. Exclusion criteria included a history of chronic corticosteroid administration.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among children enrolled in LAPSE, 352 of 392 met analysis inclusion criteria, and 155 of 352 (44%) received early corticosteroid therapy. After weighting corticosteroid therapy administration propensity across potentially confounding baseline characteristics, differences in outcomes associated with treatment were not statistically significant (adjusted effect or odds ratio [95% CI]): vasoactive-inotropic support duration (-0.37 d [-1.47 to 0.72]; p = 0.503), short-term survival without new morbidity (1.37 [0.83-2.28]; p = 0.218), new morbidity among month-1 survivors (0.70 [0.39-1.23]; p = 0.218), and persistent severe deterioration of health-related quality of life or mortality at month 1 (0.70 [0.40-1.23]; p = 0.212).

CONCLUSIONS

This study examined the association of early corticosteroid therapy with mortality and morbidity among children encountering septic shock. After adjusting for variables with the potential to confound the relationship between early corticosteroid administration and clinically meaningful end points, there was no improvement in outcomes associated with this therapy. Results from this propensity analysis provide additional justification for equipoise regarding corticosteroid therapy for pediatric septic shock and ascertain the need for a well-designed clinical trial to examine benefit/risk for this intervention.

Sex-Related Signaling of Aldosterone/Mineralocorticoid Receptor Pathway in Calcific Aortic Stenosis

BACKGROUND

There are sex differences in the pathophysiology of aortic valve (AV) calcification in patients with aortic stenosis, although the molecular and cellular mechanisms have not been elucidated. Aldosterone (Aldo) promotes proteoglycan synthesis in valve interstitial cells (VICs) from mitral valves via the mineralocorticoid receptor (MR). We investigated the influence of sex in the role of Aldo/MR pathway in AV alterations in patients with aortic stenosis.

METHODS AND RESULTS

MR was expressed by primary aortic VICs and in AVs from patients with aortic stenosis. MR expression positively correlated with VIC activation markers in AVs from both sexes. However, MR expression was positively associated with molecules involved in AV calcification only in AV from men. Aldo enhanced VIC activation markers in cells from men and women. Interestingly, Aldo increased the expression of calcification markers only in VICs isolated from men. In female VICs, Aldo enhanced fibrotic molecules. MR antagonism (spironolactone) blocked all the above effects. Cytokine arrays showed ICAM (intercellular adhesion molecule)-1 and osteopontin to be specifically increased by Aldo in male VICs. In AVs from men, MR expression positively associated with both ICAM-1 (intercellular adhesion molecule-1) and osteopontin. Only in female VICs, estradiol treatment blocked Aldo-induced VICs activation, inflammation, and fibrosis.

CONCLUSIONS

These findings demonstrate that the Aldo/MR pathway could play a role in early stages of aortic stenosis by promoting VICs activation, fibrosis, and ulterior calcification. Importantly, Aldo/MR pathway is involved in fibrosis in women and in early AV calcification only in men. Accordingly, MR antagonism emerges as a new sex-specific pharmacological treatment to prevent AV alterations.

Roles of Mineralocorticoid Receptors in Cardiovascular and Cardiorenal Diseases

Mineralocorticoid receptor (MR) activation in the heart and vessels leads to pathological effects, such as excessive extracellular matrix accumulation, oxidative stress, and sustained inflammation. In these organs, the MR is expressed in cardiomyocytes, fibroblasts, endothelial cells, smooth muscle cells, and inflammatory cells. We review the accumulating experimental and clinical evidence that pharmacological MR antagonism has a positive impact on a battery of cardiac and vascular pathological states, including heart failure, myocardial infarction, arrhythmic diseases, atherosclerosis, vascular stiffness, and cardiac and vascular injury linked to metabolic comorbidities and chronic kidney disease. Moreover, we present perspectives on optimization of the use of MR antagonists in patients more likely to respond to such therapy and review the evidence suggesting that novel nonsteroidal MR antagonists offer an improved safety profile while retaining their cardiovascular protective effects. Finally, we highlight future therapeutic applications of MR antagonists in cardiovascular injury.

Endothelial mineralocorticoid receptor ablation confers protection towards endothelial dysfunction in experimental diabetes in mice

AIM

With diabetes comes a significant risk of macrovascular and microvascular complications. Circulating aldosterone levels increase in patients with diabetes. Aldosterone can directly affect vascular function via activation of the mineralocorticoid receptor (MR). We hypothesized that aldosterone via endothelial MR impairs endothelial function in a murine model of experimental diabetes.

METHOD

Endothelial cell-specific mineralocorticoid receptor knockout MR^flox/flox ; Tie2-Cre mice (ECMR-KO) and wild-type FVB littermates were subjected to an experimental type-1 diabetic model by low dose streptozotocin injections (55mg/kg/day) for five consecutive days. After 10 weeks of diabetes, second-order mesenteric resistance arteries were perfused ex vivo to evaluate vessel contractility and endothelial function. The effect of ex vivo incubation with aldosterone with and without the antagonist, spironolactone was determined.

RESULTS

Diabetic ECMR-KO and wild-type mice had similar, elevated, plasma aldosterone concentration while only diabetic wild-type mice displayed elevated urine albumin excretion and cardiac and kidney hypertrophy at 10 weeks. There were no differences in contraction (Emax and EC₅₀ ) to thromboxane receptor agonist (U46619) and elevated K⁺ between groups. Wild-type diabetic mice showed impaired acetylcholine (ACh)-dependent relaxation, while diabetic ECMR-KO mice had intact ACh-mediated relaxation. Aldosterone incubation ex vivo impaired ACh mediated relaxation and rendered responses similar to diabetic WT arteries. Direct, ex vivo aldosterone effects were absent in ECMR-KO animals. Ex vivo inhibitory effects of aldosterone on endothelial relaxation in arteries from WT were abolished by spironolactone.

CONCLUSION

These findings show that endothelial cell mineralocorticoid receptor activation accounts for diabetes-induced systemic endothelial dysfunction in experimental diabetes and may explain the cardiovascular protection by MR antagonists in diabetes.

The Cortisol Response of Male and Female Choroidal Endothelial Cells: Implications for Central Serous Chorioretinopathy

CONTEXT

Central serous chorioretinopathy (CSC) is a severe ocular disease characterized by fluid accumulation under the retina and abnormalities in the underlying vascular layer, the choroid. CSC has a striking prevalence in males of 80% to 90% of total patients. Corticosteroids are the most pronounced extrinsic risk factor for CSC. Choroidal endothelial cells (CECs) are important for the vascular integrity of the choroid, but the effects of corticosteroid effects in these cells are unknown.

OBJECTIVE

We aimed to reveal the potential steroidal contribution to CSC.

METHOD

We characterized the expression of the glucocorticoid, mineralocorticoid, and androgen receptor in the human choroid using immunohistochemistry. Using RNA-sequencing, we describe the cortisol response in human CECs derived from 5 male and 5 female postmortem donors.

RESULTS

The glucocorticoid receptor was highly expressed in the human choroid, whereas no to minimal expression of the mineralocorticoid and androgen receptors was observed. The extensive transcriptional response to cortisol in human primary cultured CECs showed interindividual differences but very few sex differences. Several highly regulated genes such as ZBTB16 (log2 fold change males 7.9; females 6.2) provide strong links to choroidal vascular regulation.

CONCLUSIONS

The glucocorticoid receptor predominantly mediates the response to cortisol in human CECs. Interindividual differences are an important determinant regarding the cortisol response in human cultured CECs, whereas intrinsic sex differences appear less pronounced. The marked response of particular target genes in endothelial cells to cortisol, such as ZBTB16, warrants further investigation into their potential role in the pathophysiology of CSC and other vascular conditions.

Vascular and hormonal interactions in the adrenal gland

Primary aldosteronism is the most common form of secondary arterial hypertension, due to excessive aldosterone production from the adrenal gland. Although somatic mutations have been identified in aldosterone producing adenoma, the exact mechanisms leading to increased cell proliferation and nodule formation remain to be established. One hypothesis is that changes in vascular supply to the adrenal cortex, due to phenomena of atherosclerosis or high blood pressure, may influence the morphology of the adrenal cortex, resulting in a compensatory growth and nodule formation in response to local hypoxia. In this review, we will summarize our knowledge on the mechanisms regulating adrenal cortex development and function, describe adrenal vascularization in normal and pathological conditions and address the mechanisms allowing the cross-talk between the hormonal and vascular components to allow the extreme tissue plasticity of the adrenal cortex in response to endogenous and exogenous stimuli. We will then address recent evidence suggesting a role for alterations in the vascular compartment that could eventually be involved in nodule formation and the development of primary aldosteronism.

KCNJ5 Somatic Mutation Is Associated With Higher Aortic Wall Thickness and Less Calcification in Patients With Aldosterone-Producing Adenoma

OBJECTIVE

Primary aldosteronism (PA) is the most common type of secondary hypertension, and it is associated with a higher rate of cardiovascular complications. KCNJ5 somatic mutations have recently been identified in aldosterone-producing adenoma (APA), however their influence on vascular remodeling and injury is still unclear. The aim of this study was to investigate the association between KCNJ5 somatic mutation status and vascular status.

METHODS

We enrolled 179 APA patients who had undergone adrenalectomy from a prospectively maintained database, of whom 99 had KCNJ5 somatic mutations. Preoperative clinical, biochemical and imaging data of abdominal CT, including abdominal aortic calcification (AAC) score, aortic diameter and wall thickness at levels of superior (SMA) and inferior (IMA) mesenteric arteries were analyzed.

RESULTS

After propensity score matching for age, sex, body mass index, triglycerides and low-density lipoprotein, there were 48 patients in each KCNJ5 (+) and KCNJ5 (-) group. Mutation carriers had a lower AAC score (217.3 ± 562.2 vs. 605.6 ± 1359.1, P=0.018), higher aortic wall thickness (SMA level: 2.2 ± 0.6 mm vs. 1.8 ± 0.6 mm, P=0.006; IMA level: 2.4 ± 0.6 mm vs. 1.8 ± 0.7 mm, P<0.001) than non-carriers. In multivariate analysis, KCNJ5 mutations were independently associated with AAC score (P=0.014) and aortic wall thickness (SMA level: P<0.001; IMA level: P=0.004). After adrenalectomy, mutation carriers had less aortic wall thickness progression than non-carriers (Δthickness SMA: -0.1 ± 0.8 mm vs. 0.9 ± 0.6 mm, P=0.024; IMA: -0.1 ± 0.6 mm vs. 0.8 ± 0.7 mm, P=0.04).

CONCLUSION

KCNJ5 mutation carriers had less calcification burden of the aorta, thickened aortic wall, and less wall thickness progression than non-carriers.

Research progress on inflammatory mechanism of primary Sjögren syndrome

Primary Sjögren syndrome is an autoimmune disease, in which a large number of lymphocytes infiltrate the exocrine glands and cause gland dysfunction. Its pathogenesis is related to the chronic inflammation of the exocrine glands caused by genetic factors, immunodeficiency or viral infection. Long-term inflammation leads to accelerated apoptosis of epithelial cells, disordered gland structure, increased expression of proinflammatory cytokine such as CXC subfamily ligand (CXCL) 12, CXCL13, B cell-activating factor (BAF), interleukin (IL)-6, interferon (IFN)-γ and tumor necrosis factor (TNF)-α in submandibular gland. With the action of antigen-presenting cells such as dendritic cells and macrophages, lymphocytes (mainly B cells) are induced to mature in secondary lymphoid organs and migrate to the submandibular gland to promotes the formation of germinal centers and the synthesis of autoantibodies. Meanwhile, innate lymphocytes, vascular endothelial cells and mucosa-associated constant T cells as important immune cells, also participated in the inflammatory response of the submandibular gland in primary Sjögren syndrome through different mechanisms. This process involves the activation of multiple signal pathways such as JAK/STAT, MAPK/ERK, PI3K/AKT/mTOR, PD-1/PD-L1, TLR/MyD88/NF-κB, BAF/BAF-R and IFN. These signaling pathways interact with each other and are intricately complex, causing lymphocytes to continuously activate and invade the submandibular glands. This article reviews the latest literature to clarify the mechanism of submandibular gland inflammation in primary Sjögren syndrome, and to provide insights for further research.

Coronary Vasculature and Myocardial Structure in HIV: Physiologic Insights From the Renin-Angiotensin-Aldosterone System

The landscape of HIV medicine dramatically changed with the advent of contemporary antiretroviral therapies, which has allowed persons with HIV (PWH) to achieve good virologic control, essentially eliminating HIV-related complications and increasing life expectancy. As PWH are living longer, noncommunicable diseases, such as cardiovascular disease (CVD), have become a leading cause of morbidity and mortality in PWH with rates that are 50% to 100% higher than in well-matched persons without HIV. In this review, we focus on disease of the coronary microvasculature and myocardium in HIV. We highlight a key hormonal system important to cardiovascular endocrinology, the renin-angiotensin-aldosterone system (RAAS), as a potential mediator of inflammatory driven-vascular and myocardial injury and consider RAAS blockade as a physiologically targeted strategy to reduce CVD in HIV.

Myeloid Mineralocorticoid Receptor Transcriptionally Regulates P-Selectin Glycoprotein Ligand-1 and Promotes Monocyte Trafficking and Atherosclerosis

Objective

MR (mineralocorticoid receptor) activation associates with increased risk of cardiovascular ischemia while MR inhibition reduces cardiovascular-related mortality and plaque inflammation in mouse atherosclerosis. MR in myeloid cells (My-MR) promotes inflammatory cell infiltration into injured tissues and atherosclerotic plaque inflammation by unclear mechanisms. Here, we examined the role of My-MR in leukocyte trafficking and the impact of sex.

Approach and Results

We confirm in vivo that My-MR deletion (My-MR-KO) in ApoE-KO mice decreased plaque size. Flow cytometry revealed fewer plaque macrophages with My-MR-KO. By intravital microscopy, My-MR-KO significantly attenuated monocyte slow-rolling and adhesion to mesenteric vessels and decreased peritoneal infiltration of myeloid cells in response to inflammatory stimuli in male but not female mice. My-MR-KO mice had significantly less PSGL1 (P-selectin glycoprotein ligand 1) mRNA in peritoneal macrophages and surface PSGL1 protein on circulating monocytes in males. In vitro, MR activation with aldosterone significantly increased PSGL1 mRNA only in monocytes from MR-intact males. Similarly, aldosterone induced, and MR antagonist spironolactone inhibited, PSGL1 expression in human U937 monocytes. Mechanistically, aldosterone stimulated MR binding to a predicted MR response element in intron-1 of the PSGL1 gene by ChIP-qPCR. Reporter assays demonstrated that this PSGL1 MR response element is necessary and sufficient for aldosterone-activated, MR-dependent transcriptional activity.

Conclusions

These data identify PSGL1 as a My-MR target gene that drives leukocyte trafficking to enhance atherosclerotic plaque inflammation. These novel and sexually dimorphic findings provide insight into increased ischemia risk with MR activation, cardiovascular protection in women, and the role of MR in atherosclerosis and tissue inflammation.

Mineralocorticoid receptor in cardiovascular diseases-Clinical trials and mechanistic insights

Aldosterone binds to the mineralocorticoid receptor (NR3C2), a transcription factor of the nuclear receptor family, present in the kidney and in various other non-epithelial cells including the heart and the vasculature. Indeed, extra-renal pathophysiological effects of this hormone have been characterized, extending its actions to the cardiovascular system. A growing body of clinical and pre-clinical evidence suggests that mineralocorticoid receptor overactivation plays an important pathophysiological role in cardiovascular remodelling by promoting cardiac hypertrophy, fibrosis, arterial stiffness and in inflammation and oxidative stress. The following review article outlines the role of mineralocorticoid receptor in cardiovascular disease with a focus on myocardial remodelling and heart failure (HF) including clinical trials as well as cellular and animal studies.

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.

Detrimental or beneficial: Role of endothelial ENaC in vascular function

In the past, it was believed that the expression of the epithelial sodium channel (ENaC) was restricted to epithelial tissues, such as the distal nephron, airway, sweat glands, and colon, where it is critical for sodium homeostasis. Over the past two decades, this paradigm has shifted due to the finding that ENaC is also expressed in various nonepithelial tissues, notably in vascular endothelial cells. In this review, the recent findings of the expression, regulation, and function of the endothelial ENaC (EnNaC) are discussed. The expression of EnNaC subunits is reported in a variety of endothelial cell lines and vasculatures, but this is controversial across different species and vessels and is not a universal finding in all vascular beds. The expression density of EnNaC is very faint compared to ENaC in the epithelium. To date, little is known about the regulatory mechanism of EnNaC. Through it can be regulated by aldosterone, the detailed downstream signaling remains elusive. EnNaC responds to increased extracellular sodium with the feedforward activation mechanism, which is quite different from the Na⁺ self-inhibition mechanism of ENaC. Functionally, EnNaC was shown to be a determinant of cellular mechanics and vascular tone as it can sense shear stress, and its activation or insertion into plasma membrane causes endothelial stiffness and reduced nitric oxide production. However, in some blood vessels, EnNaC is essential for maintaining the integrity of endothelial barrier function. In this context, we discuss the possible reasons for the distinct role of EnNaC in vasculatures.

Current and emerging drug targets in heart failure treatment

After initial strategies targeting inotropism and congestion, the neurohormonal interpretative model of heart failure (HF) pathophysiology has set the basis for current pharmacological management of HF, as most of guideline recommended drug classes, including beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and mineralocorticoid receptor antagonists, blunt the activation of detrimental neurohormonal axes, namely sympathetic and renin–angiotensin–aldosterone (RAAS) systems. More recently, sacubitril/valsartan, a first-in-class angiotensin receptor neprilysin inhibitor, combining inhibition of RAAS and potentiation of the counter-regulatory natriuretic peptide system, has been consistently demonstrated to reduce mortality and HF-related hospitalization. A number of novel pharmacological approaches have been tested during the latest years, leading to mixed results. Among them, drugs acting directly at a second messenger level, such as the soluble guanylate cyclase stimulator vericiguat, or other addressing myocardial energetics and mitochondrial function, such as elamipretide or omecamtiv-mecarbil, will likely change the therapeutic management of patients with HF. Sodium glucose cotransporter 2 inhibitors, initially designed for the management of type 2 diabetes mellitus, have been recently demonstrated to improve outcome in HF, although mechanisms of their action on cardiovascular system are yet to be elucidated. Most of these emerging approaches have shifted the therapeutic target from neurohormonal systems to the heart, by improving cardiac contractility, metabolism, fibrosis, inflammation, and remodeling. In the present paper, we review from a pathophysiological perspective current and novel therapeutic strategies in chronic HF.

Exploring the choroidal vascular labyrinth and its molecular and structural roles in health and disease

The choroid is a key player in maintaining ocular homeostasis and plays a role in a variety of chorioretinal diseases, many of which are poorly understood. Recent advances in the field of single-cell RNA sequencing have yielded valuable insights into the properties of choroidal endothelial cells (CECs). Here, we review the role of the choroid in various physiological and pathophysiological mechanisms, focusing on the role of CECs. We also discuss new insights regarding the phenotypic properties of CECs, CEC subpopulations, and the value of measuring transcriptomics in primary CEC cultures derived from post-mortem eyes. In addition, we discuss key phenotypic, structural, and functional differences that distinguish CECs from other endothelial cells such as retinal vascular endothelial cells. Understanding the specific clinical and molecular properties of the choroid will shed new light on the pathogenesis of the broad clinical range of chorioretinal diseases such as age-related macular degeneration, central serous chorioretinopathy and other diseases within the pachychoroid spectrum, uveitis, and diabetic choroidopathy. Although our knowledge is still relatively limited with respect to the clinical features and molecular pathways that underlie these chorioretinal diseases, we summarise new approaches and discuss future directions for gaining new insights into these sight-threatening diseases and highlight new therapeutic strategies such as pluripotent stem cell‒based technologies and gene therapy.

Neurohormones, inflammatory mediators, and cardiovascular injury in the setting of heart failure

Neurohormones and inflammatory mediators have effects in both the heart and the peripheral vasculature. In patients with heart failure (HF), neurohormonal activation and increased levels of inflammatory mediators promote ventricular remodeling and development of HF, as well as vascular dysfunction and arterial stiffness. These processes may lead to a vicious cycle, whereby arterial stiffness perpetuates further ventricular remodeling leading to exacerbation of symptoms. Although significant advances have been made in the treatment of HF, currently available treatment strategies slow, but do not halt, this cycle. The current treatment for HF patients involves the inhibition of neurohormonal activation, which can reduce morbidity and mortality related to this condition. Beyond benefits associated with neurohormonal blockade, other strategies have focused on inhibition of inflammatory pathways implicated in the pathogenesis of HF. Unfortunately, attempts to target inflammation have not yet been successful to improve prognosis of HF. Further work is required to interrupt key maladaptive mechanisms involved in disease progression.

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.

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

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