Pharmacokinetics and Pharmacodynamics of Mineralocorticoid Blocking Agents and their Effects on Potassium Homeostasis

A Trial of Finerenone in a Patient with Primary Aldosteronism

INTRODUCTION

Primary aldosteronism (PA), a common secondary cause of arterial hypertension, is treated either surgically or pharmacologically with mineralocorticoid receptor antagonists (MRAs). These drugs, while effective, can cause allergic reactions and have side effects, including menstrual cycle disorders in women. Finerenone is a new, highly selective, nonsteroidal MRA with excellent side-effect profile, primarily intended to slow the progression of diabetic kidney disease and improve cardiovascular outcomes in these patients. No data are available so far on its effect on patients with PA.

CASE PRESENTATION

A case of a female patient with confirmed primary aldosteronism, in whom adrenal vein sampling failed twice is presented. The patient developed a skin allergic reaction to spironolactone and experienced prolonged vaginal bleedings with eplerenone, which was attributed to the drug's affinity for progesterone receptors. A trial of finerenone was initiated, resulting in mild increase in plasma renin activity and serum potassium, and somewhat control of blood pressure, but far from optimal blood pressure control, normokalemia, or unsuppression of plasma renin activity.

CONCLUSION

This case highlights the challenges of managing PA and describes an attempt of treatment with finerenone to which this patient unfortunately did not adequately respond.

Prenatal exposure to the mineralocorticoid receptor antagonist spironolactone disrupts hippocampal area CA2 connectivity and alters behavior in mice

In the brain, the hippocampus is enriched with mineralocorticoid receptors (MR; Nr3c2), a ligand-dependent transcription factor stimulated by the stress hormone corticosterone in rodents. Recently, we discovered that MR is required for the acquisition and maintenance of many features of mouse area CA2 neurons. Notably, we observed that immunofluorescence for the vesicular glutamate transporter 2 (vGluT2), likely representing afferents from the supramammillary nucleus (SuM), was disrupted in the embryonic, but not postnatal, MR knockout mouse CA2. To test whether pharmacological perturbation of MR activity in utero similarly disrupts CA2 connectivity, we implanted slow-release pellets containing the MR antagonist spironolactone in mouse dams during mid-gestation. After confirming that at least one likely active metabolite crossed from the dams' serum into the embryonic brains, we found that spironolactone treatment caused a significant reduction of CA2 axon fluorescence intensity in the CA1 stratum oriens, where CA2 axons preferentially project, and that vGluT2 staining was significantly decreased in both CA2 and dentate gyrus in spironolactone-treated animals. We also found that spironolactone-treated animals exhibited increased reactivity to novel objects, an effect similar to what is seen with embryonic or postnatal CA2-targeted MR knockout. However, we found no difference in preference for social novelty between the treatment groups. We infer these results to suggest that persistent or more severe disruptions in MR function may be required to interfere with this type of social behavior. These findings do indicate, though, that developmental disruption in MR signaling can have persistent effects on hippocampal circuitry and behavior.

Increased Spironolactone Dosing in Acute Heart Failure Alters Potassium Homeostasis but Does not Enhance Decongestion

BACKGROUND

The ATHENA-HF (Aldosterone Targeted Neurohormonal Combined with Natriuresis Therapy in Heart Failure) clinical trial found no improvements in natriuretic peptide levels or clinical congestion when spironolactone 100 mg/day for 96 hours was used in addition to usual treatment for acute heart failure.

METHODS

We performed a post hoc analysis of ATHENA-HF to determine whether spironolactone treatment induced any detectable pharmacodynamic effects and whether patients with potentially greater aldosterone activity experienced additional decongestion. Trial subjects previously treated with spironolactone were excluded. We first examined for changes in renal potassium handling. Using the baseline serum potassium level as a surrogate marker of spironolactone activity, we then divided each treatment arm into tertiles of baseline serum potassium and explored for differences in laboratory and clinical congestion outcomes.

RESULTS

Among spironolactone-naïve patients, the change in serum potassium did not differ after 24 hours or 48 hours but was significantly greater with spironolactone treatment compared to placebo at 72 hours (0.23 ± 0.55 vs 0.03 ± 0.60 mEq/L; P = 0.042) and 96 hours (0.32 ± 0.51 vs 0.13 ± 0.72 mEq/L; P = 0.046). Potassium supplementation was similar at treatment start and at 24 hours, but spironolactone-treated patients required substantially less potassium replacement at 48 hours (24% vs 36%; P = 0.048), 72 hours (21% vs 37%; P = 0.013), and 96 hours (11% vs 38%; P < 0.001). When the treatment arms were divided into tertiles of baseline serum potassium, there were no differences in the 96-hour log N-terminal pro-B-type natriuretic peptide levels, net fluid loss, urine output, or dyspnea relief in any of the potassium groups, with no effect modification by treatment exposure.

CONCLUSIONS

Spironolactone 100 mg/day for 96 hours in patients receiving intravenous loop diuresis for acute heart failure has no clear added decongestive ability but does meaningfully limit potassium wasting.

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.

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.

Aldosterone Antagonism Is More Effective at Reducing Blood Pressure and Excessive Renal ENaC Activity in AngII-Infused Female Rats Than in Males

BACKGROUND

AngII (angiotensin II)-dependent hypertension causes comparable elevations of blood pressure (BP), aldosterone levels, and renal ENaC (epithelial Na+ channel) activity in male and female rodents. Mineralocorticoid receptor (MR) antagonism has a limited antihypertensive effect associated with insufficient suppression of renal ENaC in male rodents with AngII-hypertension. While MR blockade effectively reduces BP in female mice with salt-sensitive and leptin-induced hypertension, MR antagonism has not been studied in female rodents with AngII-hypertension. We hypothesize that overstimulation of renal MR signaling drives redundant ENaC-mediated Na+ reabsorption and BP increase in female rats with AngII-hypertension.

METHODS

We employ a combination of physiological, pharmacological, biochemical, and biophysical approaches to compare the effect of MR inhibitors on BP and ENaC activity in AngII-infused male and female Sprague Dawley rats.

RESULTS

MR blockade markedly attenuates AngII-hypertension in female rats but has only a marginal effect in males. Spironolactone increases urinary sodium excretion and urinary sodium-to-potassium ratio in AngII-infused female, but not male, rats. The expression of renal MR and HSD11β2 (11β-hydroxysteroid dehydrogenase type 2) that determines the availability of MR to aldosterone is significantly higher in AngII-infused female rats than in males. ENaC activity is ≈2× lower in spironolactone-treated AngII-infused female rats than in males. Reduced ENaC activity in AngII-infused female rats on spironolactone correlates with increased interaction with ubiquitin ligase Nedd4-2 (neural precursor cell expressed developmentally down-regulated protein 4-2), targeting ENaC for degradation.

CONCLUSIONS

MR-ENaC axis is the primary determinant of excessive renal sodium reabsorption and an attractive antihypertensive target in female rats with AngII-hypertension, but not in males.

Effect of spironolactone on pharmacological treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) was recently renamed to metabolic (dysfunction)-associated fatty liver disease (MAFLD) to better characterize its pathogenic origin. NAFLD represents, at least in western societies, a potential epidemic with raising prevalence. Its multifactorial pathogenesis is partially unraveled and till now there is no approved pharmacotherapy for NAFLD. A plethora of various choices are investigated in clinical trials, targeting an arsenal of different pathways and molecules. Since the mineralocorticoid receptor (MR) and renin-angiotensin-aldosterone system (RAAS) appear to be implicated in NAFLD, within this concise review, we focus on a rather classical and inexpensive pharmacological agent, spironolactone. We present the current lines of evidence of MR and RAAS-related preclinical models and human trials reporting an association with NAFLD. In conclusion, evidence about spironolactone of RAAS is commented, as potential future pharmacological management of NAFLD.

Estradiol and Spironolactone Plasma Pharmacokinetics Among Brazilian Transgender Women Using HIV Pre-Exposure Prophylaxis: Analysis of Potential Interactions

BACKGROUND AND OBJECTIVE

An important barrier to HIV prevention among transgender women (TGW) is the concern that oral pre-exposure prophylaxis (PrEP) negatively affects the efficacy of feminizing hormone therapy (FHT). We aimed to assess the impact of PrEP on FHT pharmacokinetics (PK) among TGW from Brazil.

METHODS

We performed a drug-drug interaction sub-study among TGW enrolled in a daily oral PrEP demonstration study (PrEParadas, NCT03220152). Participants had a first PK assessment (PK1) 15 days after FHT (estradiol valerate 2-6 mg plus spironolactone 100-200 mg) initiation and then started PrEP (tenofovir disoproxil fumarate 300 mg/emtricitabine 200 mg). A second PK evaluation was performed 12 weeks later (PK2). Blood samples were collected prior and after the directly observed dosing (0, 0.5, 1, 2, 4, 6, 8, and 24 hours). Pharmacokinetic parameters of estradiol, spironolactone, and metabolites were estimated by non-compartmental analysis (Monolix 2021R2, Lixoft®) and compared as geometric mean ratios (GMRs, 90% confidence interval [CI]).

RESULTS

Among 19 TGW who completed the substudy, median age was 26 years (interquartile range: 23-27.5). Estradiol area under the plasma concentration-time curve (AUCτ) and trough concentrations did not differ between PK1 and PK2 evaluations (GMR [90% CI]: 0.89 [0.76-1.04] and 1.06 [0.94-1.20], respectively). Spironolactone and canrenone AUCτ were statistically lower at PK2 than PK1 (0.76 [0.65-0.89] and 0.85 [0.78-0.94], respectively). Canrenone maximum concentration was also lower at PK2 than PK1 (0.82 [0.74-0.91]).

CONCLUSION

Estradiol PK was not influenced by PrEP concomitant use. The small differences observed in some spironolactone and canrenone PK parameters should not prevent the concomitant use of estradiol-based FHT and PrEP.

TRIAL REGISTRATION

This trial (NCT03220152) was registered on July 18, 2017.

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.

Association between spironolactone use and COVID-19 outcomes in population-scale claims data: a retrospective cohort study

Background

Spironolactone has been proposed as a potential modulator of SARS-CoV-2 cellular entry. We aimed to measure the effect of spironolactone use on the risk of adverse outcomes following COVID-19 hospitalization.

Methods

We performed a retrospective cohort study of COVID-19 outcomes for patients with or without exposure to spironolactone, using population-scale claims data from the Komodo Healthcare Map. We identified all patients with a hospital admission for COVID-19 in the study window, defining treatment status based on spironolactone prescription orders. The primary outcomes were progression to respiratory ventilation or mortality during the hospitalization. Odds ratios (OR) were estimated following either 1:1 propensity score matching (PSM) or multivariable regression. Subgroup analysis was performed based on age, gender, body mass index (BMI), and dominant SARS-CoV-2 variant.

Findings

Among 898,303 eligible patients with a COVID-19-related hospitalization, 16,324 patients (1.8%) had a spironolactone prescription prior to hospitalization. 59,937 patients (6.7%) met the ventilation endpoint, and 26,515 patients (3.0%) met the mortality endpoint. Spironolactone use was associated with a significant reduction in odds of both ventilation (OR 0.82; 95% CI: 0.75-0.88; p < 0.001) and mortality (OR 0.88; 95% CI: 0.78-0.99; p = 0.033) in the PSM analysis, supported by the regression analysis. Spironolactone use was associated with significantly reduced odds of ventilation for all age groups, men, women, and non-obese patients, with the greatest protective effects in younger patients, men, and non-obese patients.

Interpretation

Spironolactone use was associated with a protective effect against ventilation and mortality following COVID-19 infection, amounting to up to 64% of the protective effect of vaccination against ventilation and consistent with an androgen-dependent mechanism. The findings warrant initiation of large-scale randomized controlled trials to establish a potential therapeutic role for spironolactone in COVID-19 patients.

A Comprehensive Outlook on Dilated Cardiomyopathy (DCM): State-Of-The-Art Developments with Special Emphasis on OMICS-Based Approaches

Dilated cardiomyopathy (DCM) remains an enigmatic cardiovascular disease (CVD) condition characterized by contractile dysfunction of the myocardium due to dilation of the ventricles. DCM is one of the major forms of CVD contributing to heart failure. Dilation of the left or both ventricles with systolic dysfunction, not explained by known causes, is a hallmark of DCM. Progression of DCM leads to heart failure. Genetic and various other factors greatly contribute to the development of DCM, but the etiology has still remained elusive in a large number of cases. A significant number of studies have been carried out to identify the genetic causes of DCM. These candidate-gene studies revealed that mutations in the genes of the fibrous, cytoskeletal, and sarcomeric proteins of cardiomyocytes result in the development of DCM. However, a significant proportion of DCM patients are idiopathic in nature. In this review, we holistically described the symptoms, causes (in adults and newborns), genetic basis, and mechanistic progression of DCM. Further, we also summarized the state-of-the-art diagnosis, available biomarkers, treatments, and ongoing clinical trials of potential drug regimens. DCM-mediated heart failure is on the rise worldwide including in India. The discovery of biomarkers with a better prognostic value is the need of the hour for better management of DCM-mediated heart failure patients. With the advent of next-generation omics-based technologies, it is now possible to probe systems-level alterations in DCM patients pertaining to the identification of novel proteomic and lipidomic biomarkers. Here, we also highlight the onset of a systems-level study in Indian DCM patients by applying state-of-the-art mass-spectrometry-based “clinical proteomics” and “clinical lipidomics”.

Rational drug therapy of chronic heart failure: the role of mineralocorticoid receptor antagonists: review

Mineralocorticoid receptor antagonists (MRAs) are part of basic medical therapy for heart failure. The clinical efficacy of MRAs has been proven by randomized clinical trials. To review comparative efficacy and tolerability data between the two main MRAs, spironolactone and eplerenone, in patients with systolic heart failure.

Sex Differences in Spironolactone and the Active Metabolite Canrenone Concentrations and Adherence

We aim to investigate sex differences in blood concentrations of spironolactone and the active metabolite canrenone in resistant hypertension patients. Furthermore, sex differences in adherence for spironolactone and other antihypertensive drugs (AHDs) were studied. The patients in this post hoc study had all participated in a single-blind randomized controlled trial called RHYME-RCT (Dutch Trial Register, NL6736). Concentrations in blood of several AHDs were assessed in RHYME-RCT to investigate adherence to treatment. This allowed for a comparison of drug exposure to spironolactone and canrenone between males and females. In linear regression models, no statistically significant sex differences (N = 35) in spironolactone (B =−10.23, SE = 7.92, p = 0.206) or canrenone (B = 1.24, SE = 10.96, p = 0.911) concentrations after adjustment for dose and time between sampling and intake were found. Furthermore, no statistically significant differences in non-adherence to spironolactone were found between sexes (N = 54, male 15% vs. female 38%, p = 0.100), but non-adherence to spironolactone was associated with non-adherence to other AHDs (p ≤ 0.001). Spironolactone and canrenone concentrations were not different between males and females with resistant hypertension. Although not statistically significant, females were twice as likely to be non-adherent to spironolactone compared to males, and thereby also more likely to be non-adherent to other AHDs.

Perioperative Considerations for Person-Centered Gender-Affirming Surgery

With more than 1 million people identifying as transgender in the United States alone, the likelihood of encountering a transgender patient and their family of choice in the perioperative setting is very high. A lack of data exists to equitably inform transgender-specific issues, as well as the associated morbidity during the transgender reassignment perioperative period. Anaesthesiologists should actively acquire the knowledge and skills needed to inclusively and respectfully manage these patients and be aware of their unique physiological and psychosocial needs. The pre-operative approach includes a detailed history, focusing on the patients cross-sex hormone treatment (CSHT) regimen and associated medical conditions. An in-depth understanding of commonly used hormones such as estrogen and testosterone and their effect in the perioperative periods is essential. The physical examination should be relevant to the anatomy that is currently present while taking into consideration feminising and masculinising procedures (e.g., genioplasty, thyroid cartilage augmentation), how these interventions alter the anatomy, and potential airway complications. Laboratory results should be interpreted with care – and with expert assistance if needed - as hormone therapy might affect reference values. In addition, risk assessment tools should be used with caution since they often include sex in their scoring system but do not account for the use of CSHT. Intraoperative considerations include urethral catheter placement, drug dosing, and drug interactions that are commonly encountered in the transgender patient. Special attention should be taken in transgender females who have undergone vocal feminization, as case reports have described unexpected difficult airway management. A multimodal approach, which includes regional blocks and attention to pre-existing chronic pain conditions, should be employed as part of the post-operative pain management plan. The post-operative nausea and vomiting risk has not yet been established in this population, requiring appropriate anti-emetic prophylaxis. Despite societal advances that improve transgender health, the medical community still lacks empirical evidence to effectively mitigate the distinctive challenges confronted by this at-risk population.

The effect of spironolactone on cardiac and renal fibrosis following myocardial infarction in established hypertension in the transgenic Cyp1a1Ren2 rat

AIMS

The renin-angiotensin-aldosterone axis plays a key role in mediating cardiac and kidney injury. Mineralocorticoid receptor antagonism has beneficial effects on cardiac dysfunction, but effects are less well quantified in the cardiorenal syndrome. This study investigated cardiac and kidney pathophysiology following permanent surgical ligation to induce myocardial infarction (MI) in hypertensive animals with or without mineralocorticoid receptor antagonism.

METHODS

Hypertension was induced in adult male Cyp1a1Ren2 rats. Hypertensive animals underwent MI surgery (n = 6), and were then treated daily with spironolactone for 28 days with serial systolic blood pressure measurements, echocardiograms and collection of urine and serum biochemical data. They were compared to hypertensive animals (n = 4), hypertensive animals treated with spironolactone (n = 4), and hypertensive plus MI without spironolactone (n = 6). Cardiac and kidney tissue was examined for histological and immunohistochemical analysis.

RESULTS

MI superimposed on hypertension resulted in an increase in interstitial cardiac fibrosis (p<0.001), renal cortical interstitial fibrosis (p<0.01) and glomerulosclerosis (p<0.01). Increased fibrosis was accompanied by myofibroblast and macrophage infiltration in the heart and the kidney. Spironolactone post-MI, diminished the progressive fibrosis (p<0.001) and inflammation (myofibroblasts (p<0.05); macrophages (p<0.01)) in both the heart and the kidney, despite persistently elevated SBP (182±19 mmHg). Despite the reduction in inflammation and fibrosis, spironolactone did not modify ejection fraction, proteinuria, or renal function when compared to untreated animals post MI.

CONCLUSION

This model of progressive cardiorenal dysfunction more closely replicates the clinical setting. Mineralocorticoid receptor blockade at a clinically relevant dose, blunted progression of cardiac and kidney fibrosis with reduction in cardiac and kidney inflammatory myofibroblast and macrophage infiltration. Further studies are underway to investigate the combined actions of angiotensin blockade with mineralocorticoid receptor blockade.

Nonsteroidal mineralocorticoid receptor antagonism for cardiovascular and renal disorders - New perspectives for combination therapy

During the recent 30 years, there has been a dramatic increase in knowledge about the role of aldosterone and the mineralocorticoid receptor (MR) in the pathophysiology of cardiovascular (CV) and kidney diseases. The scientific perspective on the aldosterone/MR ensemble extended from a previously renal epithelial-centered focus on sodium-potassium exchange to a broader view as systemic modulators of extracellular matrix, inflammation and fibrosis. Spironolactone was launched as the first antagonist of aldosterone 27 years before the MR was cloned. It was classified as a potassium-sparing diuretic, based on its initial clinical characterization as a diuretic and its preferred activity to compensate for the potassium loss induced by loop diuretics when used in combination. The second steroidal MR antagonist was eplerenone which was discovered at a time when the role of aldosterone and MR in cardiac fibrosis was rediscovered. The constraint of developing potentially life-threatening hyperkalaemia when used in combination with other inhibitors of the renin-angiotensin-system (RAS) in patients with reduced kidney function initiated extensive research and development activities with the goal to identify novel nonsteroidal MR antagonists with an improved benefit-risk ratio. Here we summarize major current clinical trials with MRAs in different CV and renal diseases. Addition of the nonsteroidal MRA finerenone to optimal RAS blockade recently reduced CV and kidney outcomes in two large phase III trials in patients with chronic kidney disease (CKD) and type 2 diabetes (T2D). We provide an outlook on further opportunities for combination therapy of nonsteroidal MRA finerenone with RAS inhibitors and sodium-glucose cotransporter-2 inhibitors (SGLT2i).

First screening of biocides, persistent organic pollutants, pharmaceutical and personal care products in Antarctic phytoplankton from Deception Island by FT-ICR-MS

In recent years, the Antarctic territory has seen a rise in the number of tourists and scientists. This has led to an increase in the anthropogenic footprint in Antarctic ecosystems, namely in terms of emerging contaminants, such as Biocides, Persistent Organic Pollutants (POPs) as well as Pharmaceutical and Personal Care Products (PPCPs). Yet scarce information on the presence of these emerging contaminants is available for trophic compartments, especially the phytoplankton community. Using high resolution Fourier-transform ion cyclotron-resonance mass spectrometry (FT-ICR-MS), an untargeted screening of the metabolome of the phytoplankton community was performed. Seventy different contaminant compounds were found to be present in phytoplankton collected at two sites in Port Foster Bay at Deception Island. These emerging contaminants included 1 polycyclic aromatic hydrocarbon (PAH), 10 biocides (acaricides, fungicides, herbicides, insecticides and nematicides), 11 POPs (flame retardants, paints and dyes, polychlorinated biphenyl (PCB), phthalates and plastic components), 5 PCPs (cosmetic, detergents and dietary compounds), 40 pharmaceutical compounds and 3 illicit drugs. Pharmaceutical compounds were, by far, the largest group of emerging contaminants found in phytoplankton cells (anticonvulsants, antihypertensives and beta-blockers, antibiotics, analgesic and anti-inflammatory drugs). The detection of several of these potentially toxic compounds at the basis of the marine food web has potentially severe impacts for the whole ecosystem trophic structure. Additionally, the present findings also point out that the guidelines proposed by the Antarctic Treaty and Protocol on Environmental Protection to the Antarctic Treaty should be revisited to avoid the proliferation of these and other PPCPs in such sensitive environments.

Polymeric micelle mediated follicular delivery of spironolactone: Targeting the mineralocorticoid receptor to prevent glucocorticoid-induced activation and delayed cutaneous wound healing

Impaired wound healing in patients receiving glucocorticoid therapy is a serious clinical concern: mineralocorticoid receptor (MR) antagonists can counter glucocorticoid-induced off-target activation of MR receptors. The aim of this study was to investigate the cutaneous delivery of the potent MR antagonist, spironolactone (SPL), from polymeric micelle nanocarriers, prepared using a biodegradable copolymer, methoxy-poly(ethylene glycol)-di-hexyl-substituted-poly(lactic acid). Immunofluorescent labelling of the MR showed that it was principally located in the pilosebaceous unit (PSU), justifying the study rationale since polymeric micelles accumulate preferentially in appendageal structures. Cutaneous biodistribution studies under infinite and finite dose conditions, demonstrated delivery of pharmacologically relevant amounts of SPL to the epidermis and upper dermis. Preferential PSU targeting was confirmed by comparing amounts of SPL in PSU-containing and PSU-free skin biopsies: SPL nanomicelles showed 5-fold higher delivery of SPL in the PSU-containing biopsies, 0.54 ± 0.18 ng/mm²vs. 0.10 ± 0.03 ng/mm², after application of a hydrogel in finite conditions. Canrenone, an active metabolite of SPL, was also quantified in skin samples. In addition to being used for the treatment of delayed cutaneous wound healing by site-specific antagonism of the MR, the formulation might also be used to treat pilosebaceous androgen-related skin diseases, e.g. acne vulgaris, since SPL is a potent androgen receptor antagonist.

COVID-19-The Potential Beneficial Therapeutic Effects of Spironolactone during SARS-CoV-2 Infection

In March 2020, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 was declared a global pandemic by the World Health Organization (WHO). The clinical course of the disease is unpredictable but may lead to severe acute respiratory infection (SARI) and pneumonia leading to acute respiratory distress syndrome (ARDS). It has been shown that pulmonary fibrosis may be one of the major long-term complications of COVID-19. In animal models, the use of spironolactone was proven to be an important drug in the prevention of pulmonary fibrosis. Through its dual action as a mineralocorticoid receptor (MR) antagonist and an androgenic inhibitor, spironolactone can provide significant benefits concerning COVID-19 infection. The primary effect of spironolactone in reducing pulmonary edema may also be beneficial in COVID-19 ARDS. Spironolactone is a well-known, widely used and safe anti-hypertensive and antiandrogenic medication. It has potassium-sparing diuretic action by antagonizing mineralocorticoid receptors (MRs). Spironolactone and potassium canrenoate, exerting combined pleiotropic action, may provide a therapeutic benefit to patients with COVID-19 pneumonia through antiandrogen, MR blocking, antifibrotic and anti-hyperinflammatory action. It has been proposed that spironolactone may prevent acute lung injury in COVID-19 infection due to its pleiotropic effects with favorable renin–angiotensin–aldosterone system (RAAS) and ACE2 expression, reduction in transmembrane serine protease 2 (TMPRSS2) activity and antiandrogenic action, and therefore it may prove to act as additional protection for patients at highest risk of severe pneumonia. Future prospective clinical trials are warranted to evaluate its therapeutic potential.

Effects of spironolactone on extrasystoles and heart rate variability in haemodialysis patients: a randomised crossover trial

BACKGROUND

Spironolactone treatment reduces mortality in haemodialysis (HD) patients. The objective of this study was to evaluate if spironolactone affects cardiac electric activity in this population.

METHODS

Participants were randomised to start with spironolactone 50 mg daily or observation (12 weeks) with subsequent washout (6 weeks) and crossover to the other intervention (12 weeks). Long-term electrocardiograms were recorded and assessed with blinding to treatment. The primary outcome was premature ventricular complexes (PVC), and secondary outcomes were atrial premature contractions (APC) and heart rate variability (HRV).

RESULTS

Thirty participants were recruited, and data for 16 participants were included in the analysis. Treatment was associated with an increase in PVCs by 9.7 [95% confidence interval (CI): 1.5 to 18] h^-1. HRV time-domain variables increased during treatment, the standard deviation of all beat-to-beat intervals by 18 (95% CI: 3.3 to 32) milliseconds (ms) and the standard deviation of the averages of beat-to-beat intervals in all 5-min segments of the entire recording by 16 (95% CI: 1.5 to 30) ms. There were no significant differences in other variables.

CONCLUSION

Spironolactone treatment increases PVCs in HD, indicating a possible proarrhythmic effect. However, improved cardiac autonomic function, as indicated by an increased HRV, may contribute to the survival benefit from spironolactone treatment in HD patients.

Potential Anti-COVID-19 Therapeutics that Block the Early Stage of the Viral Life Cycle: Structures, Mechanisms, and Clinical Trials

The ongoing pandemic of coronavirus disease-2019 (COVID-19) is being caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The disease continues to present significant challenges to the health care systems around the world. This is primarily because of the lack of vaccines to protect against the infection and the lack of highly effective therapeutics to prevent and/or treat the illness. Nevertheless, researchers have swiftly responded to the pandemic by advancing old and new potential therapeutics into clinical trials. In this review, we summarize potential anti-COVID-19 therapeutics that block the early stage of the viral life cycle. The review presents the structures, mechanisms, and reported results of clinical trials of potential therapeutics that have been listed in clinicaltrials.gov. Given the fact that some of these therapeutics are multi-acting molecules, other relevant mechanisms will also be described. The reviewed therapeutics include small molecules and macromolecules of sulfated polysaccharides, polypeptides, and monoclonal antibodies. The potential therapeutics target viral and/or host proteins or processes that facilitate the early stage of the viral infection. Frequent targets are the viral spike protein, the host angiotensin converting enzyme 2, the host transmembrane protease serine 2, and clathrin-mediated endocytosis process. Overall, the review aims at presenting update-to-date details, so as to enhance awareness of potential therapeutics, and thus, to catalyze their appropriate use in combating the pandemic.

Targeting perivascular and epicardial adipose tissue inflammation: therapeutic opportunities for cardiovascular disease

Major shifts in human lifestyle and dietary habits toward sedentary behavior and refined food intake triggered steep increase in the incidence of metabolic disorders including obesity and Type 2 diabetes. Patients with metabolic disease are at a high risk of cardiovascular complications ranging from microvascular dysfunction to cardiometabolic syndromes including heart failure. Despite significant advances in the standards of care for obese and diabetic patients, current therapeutic approaches are not always successful in averting the accompanying cardiovascular deterioration. There is a strong relationship between adipose inflammation seen in metabolic disorders and detrimental changes in cardiovascular structure and function. The particular importance of epicardial and perivascular adipose pools emerged as main modulators of the physiology or pathology of heart and blood vessels. Here, we review the peculiarities of these two fat depots in terms of their origin, function, and pathological changes during metabolic deterioration. We highlight the rationale for pharmacological targeting of the perivascular and epicardial adipose tissue or associated signaling pathways as potential disease modifying approaches in cardiometabolic syndromes.

ACE2 as a Therapeutic Target for COVID-19; its Role in Infectious Processes and Regulation by Modulators of the RAAS System

Angiotensin converting enzyme 2 (ACE2) is the recognized host cell receptor responsiblefor mediating infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). ACE2bound to tissue facilitates infectivity of SARS-CoV-2; thus, one could argue that decreasing ACE2tissue expression would be beneficial. However, ACE2 catalytic activity towards angiotensin I (AngI) and II (Ang II) mitigates deleterious effects associated with activation of the renin-angiotensinaldosteronesystem (RAAS) on several organs, including a pro-inflammatory status. At the tissuelevel, SARS-CoV-2 (a) binds to ACE2, leading to its internalization, and (b) favors ACE2 cleavage toform soluble ACE2: these actions result in decreased ACE2 tissue levels. Preserving tissue ACE2activity while preventing ACE2 shredding is expected to circumvent unrestrained inflammatoryresponse. Concerns have been raised around RAAS modulators and their effects on ACE2expression or catalytic activity. Various cellular and animal models report conflicting results invarious tissues. However, recent data from observational and meta-analysis studies in SARS-CoV-2-infected patients have concluded that RAAS modulators do not increase plasma ACE2 levels orsusceptibility to infection and are not associated with more severe diseases. This review presentsour current but evolving knowledge of the complex interplay between SARS-CoV-2 infection, ACE2levels, modulators of RAAS activity and the effects of RAAS modulators on ACE2 expression.

Personalized Mapping of Drug Metabolism by the Human Gut Microbiome

The human gut microbiome harbors hundreds of bacterial species with diverse biochemical capabilities. Dozens of drugs have been shown to be metabolized by single isolates from the gut microbiome, but the extent of this phenomenon is rarely explored in the context of microbial communities. Here, we develop a quantitative experimental framework for mapping the ability of the human gut microbiome to metabolize small molecule drugs: Microbiome-Derived Metabolism (MDM)-Screen. Included are a batch culturing system for sustained growth of subject-specific gut microbial communities, an ex vivo drug metabolism screen, and targeted and untargeted functional metagenomic screens to identify microbiome-encoded genes responsible for specific metabolic events. Our framework identifies novel drug-microbiome interactions that vary between individuals and demonstrates how the gut microbiome might be used in drug development and personalized medicine.

Aldosterone and the mineralocorticoid receptor in renal injury: A potential therapeutic target in feline chronic kidney disease

There is a growing body of experimental and clinical evidence supporting mineralocorticoid receptor (MR) activation as a powerful mediator of renal damage in laboratory animals and humans. Multiple pathophysiological mechanisms are proposed, with the strongest evidence supporting aldosterone-induced vasculopathy, exacerbation of oxidative stress and inflammation, and increased growth factor signalling promoting fibroblast proliferation and deranged extracellular matrix homeostasis. Further involvement of the MR is supported by extensive animal model experiments where MR antagonists (such as spironolactone and eplerenone) abrogate renal injury, including ischaemia-induced damage. Additionally, clinical trials have shown MR antagonists to be beneficial in human chronic kidney disease (CKD) in terms of reducing proteinuria and cardiovascular events, though current studies have not evaluated primary end points which allow conclusions to made about whether MR antagonists reduce mortality or slow CKD progression. Although differences between human and feline CKD exist, feline CKD shares many characteristics with human disease including tubulointerstitial fibrosis. This review evaluates the evidence for the role of the MR in renal injury and summarizes the literature concerning aldosterone in feline CKD. MR antagonists may represent a promising therapeutic strategy in feline CKD.

Spironolactone mitigates, but does not reverse, the progression of renal fibrosis in a transgenic hypertensive rat

Hypertension plays an important role in the development and progression of chronic kidney disease. Studies to date, with mineralocorticoid receptor antagonists (MRA), have demonstrated varying degrees of results in modifying the development of renal fibrosis. This study aimed to investigate whether treatment with a MRA commenced following the establishment of hypertension, a situation more accurately representing the clinical setting, modified the progression of renal fibrosis. Using male Cyp1a1Ren2 rats (n = 28), hypertension was established by addition of 0.167% indole-3-carbinol (w/w) to the rat chow, for 2 weeks prior to treatment. Rats were then divided into normotensive, hypertensive (H), or hypertensive with daily oral spironolactone treatment (H + SP) (human equivalent dose 50 mg/day). Physiological data and tissue were collected after 4 and 12 weeks for analysis. After 4 weeks, spironolactone had no demonstrable effect on systolic blood pressure (SBP), proteinuria, or macrophage infiltration in the renal cortex. However, glomerulosclerosis and renal cortical fibrosis were significantly decreased. Following 12 weeks of spironolactone treatment, SBP was lowered (not back to normotensive levels), proteinuria was reduced, and the progression of glomerulosclerosis and renal cortical fibrosis was significantly blunted. This was associated with a significant reduction in macrophage and myofibroblast infiltration, as well as CTGF and pSMAD2 expression. In summary, in a model of established hypertension, spironolactone significantly blunted the progression of renal fibrosis and glomerulosclerosis, and downregulated the renal inflammatory response, which was associated with reduced proteinuria, despite only a partial reduction in systolic blood pressure. This suggests a blood pressure independent effect of MRA on renal fibrosis.

Disambiguating "Mechanisms" in Pharmacy: Lessons from Mechanist Philosophy of Science

Talk of mechanisms is ubiquitous in the natural sciences. Interdisciplinary fields such as biochemistry and pharmacy frequently discuss mechanisms with the assistance of diagrams. Such diagrams usually depict entities as structures or boxes and activities or interactions as arrows. While some of these arrows may indicate causal or componential relations, others may represent temporal or operational orders. Importantly, what kind of relation an arrow represents may not only vary with context but also be underdetermined by empirical data. In this manuscript, we investigate how an analysis of pharmacological mechanisms in terms of producing and underlying mechanisms-as discussed in the contemporary philosophy of science-may shed light on these issues. Specifically, we shall argue that while pharmacokinetic mechanisms usually describe causal chains of production, pharmacodynamics tends to focus on mechanisms of action underlying the in vivo effects of a drug. Considering the action of thyroid gland hormones in the human body as a case study, we further demonstrate that pharmacodynamic schemes tend to incorporate entities and interactions on multiple levels. Yet, traditional pharmacodynamic schemes are sketched "flat", i.e., non-hierarchically. We suggest that transforming flat pharmacodynamic schemes into mechanistic multi-level representations may assist in disentangling the different kinds of mechanisms and relations depicted by arrows in flat schemes. The resulting Baumkuchen model provides a powerful and practical alternative to traditional flat schemes, as it explicates the relevant mechanisms and relations more clearly. On a more general note, our discussion demonstrates how pharmacology and related disciplines may benefit from applying concepts from the new mechanist philosophy to guide the interpretation of scientific diagrams.

Spironolactone use is associated with lower prostate cancer risk: a population-wide case-control study

BACKGROUND

Spironolactone, a cheap effective diuretic used to manage hypertension and heart failure, also has anti-androgenic effects through its non-selective binding to steroid receptors, and hence may affect prostate cancer (PCa) risk. This study investigated the association between spironolactone use and PCa risk. For comparison, we also examined associations with thiazide diuretics which do not have anti-androgenic properties.

METHODS

A matched case-control study was undertaken using population-wide data from the Prostate Cancer Data Base Sweden (PCBaSe). All PCa cases diagnosed from 2014 to 2016 were matched by birth year and county with PCa-free controls selected from the general population (1:5). Multivariable conditional logistic regression was used to examine associations between spironolactone use (dose and duration) and PCa risk, and similarly for thiazides.

RESULTS

Three percent of the 31,591 cases and 4% of the 156,802 controls had been prescribed spironolactone. Multivariable analyses indicated reduced risk of PCa among those ever exposed to spironolactone (odds ratio [OR] 0.83; 95% confidence interval [CI]: 0.76-0.89), with a stronger association for current users (OR: 0.77, 95% CI: 0.69-0.86) than past users (OR: 0.88; 95% CI: 0.79-0.97) and decreasing risk with increasing dose (p-trend < 0.001). No association was observed for thiazide exposure and PCa risk. Biases due to differences in prescribing patterns or frequency of PSA testing may have influenced these findings.

CONCLUSION

PCa risk was reduced among men exposed to the diuretic spironolactone. Further investigation of spironolactone's potential chemopreventive effects is warranted.

Identification of clinically approved small molecules that inhibit growth and affect transcript levels of developmentally regulated genes in the African trypanosome

Trypanosoma brucei are unicellular parasites endemic to Sub-Saharan Africa that cause fatal disease in humans and animals. Infection with these parasites is caused by the bite of the tsetse fly vector, and parasites living extracellularly in the blood of infected animals evade the host immune system through antigenic variation. Existing drugs for Human and Animal African Trypanosomiasis are difficult to administer and can have serious side effects. Resistance to some drugs is also increasing, creating an urgent need for alternative trypanosomiasis therapeutics. We screened a library of 1,585 U.S. or foreign-approved drugs and identified 154 compounds that inhibit trypanosome growth. As all of these compounds have already undergone testing for human toxicity, they represent good candidates for repurposing as trypanosome therapeutics. In addition to identifying drugs that inhibit trypanosome growth, we wished to identify small molecules that can induce bloodstream form parasites to differentiate into forms adapted for the insect vector. These insect stage parasites lack the immune evasion mechanisms prevalent in bloodstream forms, making them vulnerable to the host immune system. To identify drugs that increase transcript levels of an invariant, insect-stage specific surface protein called procyclin, we engineered bloodstream reporter parasites that express Green Fluorescent Protein (GFP) following induction or stabilization of the procyclin transcript. Using these bloodstream reporter strains in combination with automated flow cytometry, we identified eflornithine, spironolactone, and phenothiazine as small molecules that increase abundance of procyclin transcript. Both eflornithine and spironolactone also affect transcript levels for a subset of differentiation associated genes. While we failed to identify compounds that increase levels of procyclin protein on the cell surface, this study is proof of principle that these fluorescent reporter parasites represent a useful tool for future small molecule or genetic screens aimed at identifying molecules or processes that initiate remodeling of the parasite surface during life cycle stage transitions.

Pharmacokinetics and Safety of Single-Dose Esaxerenone in Japanese Subjects with Mild to Moderate Hepatic Impairment

Introduction

The mineralocorticoid receptor (MR) blocker esaxerenone is a new treatment for hypertension in Japan and under development for treatment of diabetic nephropathy. Hepatic impairment is known to impact the pharmacokinetics (PKs) of other MR blocking drugs. The aim of the present study was to characterise the PKs and safety of a single oral dose of esaxerenone in Japanese subjects with mild–moderate hepatic impairment.

Methods

In this open-label, parallel-group study, subjects with mild (Child–Pugh grade A) or moderate (grade B) hepatic impairment, and healthy controls with normal hepatic function matched by age and BMI (all groups n = 6), received a single 2.5-mg oral dose of esaxerenone. Plasma concentrations were measured by liquid chromatography–tandem mass spectrometry, and PK parameters were calculated using non-compartmental analysis.

Results

Geometric least-squares mean (GLSM) ratios (90% confidence intervals [CIs]) for area under the plasma concentration–time curve (up to the last quantifiable time, up to infinity) in subjects with mild hepatic impairment versus normal hepatic function were 0.837 (0.637, 1.099) and 0.824 (0.622, 1.092), respectively. Corresponding values for moderate hepatic impairment versus normal hepatic function were 1.078 (0.820, 1.415) and 1.098 (0.829, 1.454). GLSM ratios (90% CIs) for peak plasma concentration (C_max) were 0.959 (0.778, 1.182) for mild hepatic impairment versus normal hepatic function and 0.804 (0.653, 0.992) for moderate hepatic impairment versus normal hepatic function. Time to C_max and clearance values were comparable between groups. The incidence of adverse events (AEs) was 16.7% in the moderate hepatic impairment and normal hepatic function groups. One serious AE (hepatic encephalopathy) occurred in one subject with moderate hepatic impairment.

Conclusions

Mild to moderate hepatic impairment had no clinically relevant effect on esaxerenone exposure. Esaxerenone dosage adjustment based on PKs is unlikely to be needed in patients with mild to moderate hepatic impairment.

Trial Registration

JapicCTI-163339.

Funding

Daiichi Sankyo Co., Ltd.

A short review of primary aldosteronism in a question and answer fashion

OBJECTIVES

The aim of this study was to present up to date information concerning the diagnosis and treatment of primary aldosteronism (PA). PA is the most common cause of endocrine hypertension. It has been reported up to 24% of selective referred hypertensive patients.

METHODS

We did a search in Pub-Med and Google Scholar using the terms: PA, hyperaldosteronism, idiopathic adrenal hyperplasia, diagnosis of PA, mineralocorticoid receptor antagonists, adrenalectomy, and surgery. We also did cross-referencing search with the above terms. We had divided our study into five sections: Introduction, Diagnosis, Genetics, Treatment, and Conclusions. We present our results in a question and answer fashion in order to make reading more interesting.

RESULTS

PA should be searched in all high-risk populations. The gold standard for diagnosis PA is the plasma aldosterone/plasma renin ratio (ARR). If this test is positive, then we proceed with one of the four confirmatory tests. If positive, then we proceed with a localizing technique like adrenal vein sampling (AVS) and CT scan. If the lesion is unilateral, after proper preoperative preparation, we proceed, in adrenalectomy. If the lesion is bilateral or the patient refuses or is not fit for surgery, we treat them with mineralocorticoid receptor antagonists, usually spironolactone.

CONCLUSIONS

Primary aldosteronism is the most common and a treatable case of secondary hypertension. Only patients with unilateral adrenal diseases are eligible for surgery, while patients with bilateral and non-surgically correctable PA are usually treated by mineralocorticoid receptor antagonist (MRA). Thus, the distinction between unilateral and bilateral aldosterone hypersecretion is crucial.

[Treatment of central serous chorioretinopathy with mineralocorticoid receptor antagonists]

BACKGROUND

Over 3 years have passed since the last publication on the therapeutic principle "Mineralocorticoid receptor antagonists as treatment option for acute and chronic central serous chorioretinopathy" by Maier et al., and numerous new studies have been published on the topic. The aim of this work is to provide an update on the current literature and reevaluate the role of mineralocorticoid receptor antagonists in the treatment of central serous chorioretinopathy (CSC).

METHODS AND RESULTS

A computer-based literature search in PubMed yielded a total of 20 relevant articles published from 2013 to 2017, which were evaluated in terms of the effect of mineralocorticoid receptor antagonists in CSC treatment. Due to study protocol variability with different primary endpoints and follow-up periods, an in-depth comparison of the selected studies could not be performed. Moreover, the small study populations further limit their validity in this per se heterogeneous disease spectrum. Despite these limitations, current data indicate that aldosterone antagonists are effective in decreasing subretinal fluid and improving visual acuity in patients with CSC. The selective aldosterone antagonist eplerenone with a low side effect profile is a treatment option in patients with non-resolving CSC.

CONCLUSION

Prospective, randomized studies with uniform disease definition and study criteria are necessary to validate the therapeutic effect and to determine the ideal time of intervention and treatment duration.

Mineralocorticoid Receptor Antagonists in Primary Aldosteronism

Background:

Primary aldosteronism is the most common causes of secondary hypertension. Patients suffering from this clinical syndrome have an increased cardiovascular risk and target organ damage. Mineralocorticoid receptor antagonists are the optimal pharmaceutical option for the management of such patients.

Objectives:

The study aimed to assess the effects of mineralocorticoid receptor antagonist in the treatment of patients with primary aldosteronism.

Method:

We conducted an in-depth review of the literature and comprehensive identification of the clinical studies investigating the efficacy of mineralocorticoid receptor antagonists in individuals with primary aldosteronism.

Results:

Mineralocorticoid receptor antagonists result in significant improvement in blood pressure and serum potassium level among patients with primary aldosteronism. Moreover, mineralocorticoid receptor antagonists reverse left ventricular hypertrophy, albuminuria, and carotid intima-media thickness. However, a high risk for atrial fibrillation remains among subject with primary aldosteronism in such agents.

Conclusion:

Mineralocorticoid receptor antagonists are recommended as the first-line treatment in patients with bilateral primary aldosteronism. In patients with unilateral aldosterone-producing adenoma, adrenalectomy should be preferred. However, existing data presents significant limitations and is rather inconclusive. Future randomized control trials are required in order to illustrate the field.

Mineralocorticoid Antagonist Improves Glucocorticoid Receptor Signaling and Dexamethasone Analgesia in an Animal Model of Low Back Pain

Low back pain, a leading cause of disability, is commonly treated by epidural steroid injections that target the anti-inflammatory glucocorticoid receptor (GR). However, their efficacy has been controversial. All currently used epidural steroids also activate the pro-inflammatory mineralocorticoid receptor (MR) with significant potency. Local inflammation of the dorsal root ganglia (DRG), a rat model of low back pain, was used. This model causes static and dynamic mechanical allodynia, cold allodynia and guarding behavior (a measure of spontaneous pain), and activates the MR, with pro-nociceptive effects. In this study, effects of local Dexamethasone (DEX; a glucocorticoid used in epidural injections), and eplerenone (EPL; a second generation, more selective MR antagonist) applied to the DRG at the time of inflammation were examined. Mechanical and spontaneous pain behaviors were more effectively reduced by the combination of DEX and EPL than by either alone. The combination of steroids was particularly more effective than DEX alone or the model alone (3-fold improvement for mechanical allodynia) at later times (day 14). Immunohistochemical analysis of the GR in the DRG showed that the receptor was expressed in neurons of all size classes, and in non-neuronal cells including satellite glia. The GR immunoreactivity was downregulated by DRG inflammation (48%) starting on day 1, consistent with the reduction of GR (57%) observed by Western blot, when compared to control animals. On day 14, the combination of DEX and EPL resulted in rescue of GR immunoreactivity that was not seen with DEX alone, and was more effective in reducing a marker for satellite glia activation/neuroinflammation. The results suggest that EPL may enhance the effectiveness of clinically used epidural steroid injections, in part by enhancing the availability of the GR. Thus, the glucocorticoid-mineralocorticoid interactions may limit the effectiveness of epidural steroids through the regulation of the GR in the DRG.

Microbial synthesis of mammalian metabolites of spironolactone by thermophilic fungus Thermomyces lanuginosus

Mesophilic fungi are well recognized as models of mammalian drug metabolism. Thermophilic fungi remained unexplored despite having a unique mechanism of growing at higher temperatures and performing wide diverse reactions. The present investigation is directed to isolate a promising thermophilic fungal strain capable of biotransformation using spironolactone as a model drug. Two-stage fermentation protocol was followed for the process. The transformation of spironolactone was identified by HPLC and structure elucidation of the metabolites was done with the help of LC-MS/MS analysis and previous reports. A strain of Thermomyces lanuginosus isolated from decomposed banana peel waste was found to be most promising in transforming spironolactone to 4 metabolites viz.7α-thiospironolactone (M1) canrenone (M2), 7α-thiomethylspironolactone (M3) and 6β-OH-7α-thiomethylspironolactone (M4), the major mammalian metabolites reported previously. The synthesis of metabolites of spironolactone by T. lanuginosus similar to mammals clearly states that this fungus possess enzyme system similar to mammals. Hence, this fungus has the potential to use as a model organism for studying drug metabolism.

Single- and multiple-dose escalation study to assess pharmacokinetics, pharmacodynamics and safety of oral esaxerenone in healthy Japanese subjects

AIMS

To characterize the pharmacokinetics, pharmacodynamics and safety of esaxerenone, a mineralocorticoid receptor antagonist, in healthy adult Japanese men.

METHODS

Double-blind, placebo-controlled, sequential, dose-escalation studies were conducted in subjects randomized to receive oral once-daily esaxerenone (ranges: 5-200 mg [single-dose]; 10-100 mg over 10 days [multiple-dose]) or placebo under fasting conditions. Plasma concentrations were analysed by liquid chromatograph-tandem mass spectrometry. Pharmacokinetic parameters were determined by noncompartment analysis. Plasma/urine levels of pharmacodynamic biomarkers for mineralocorticoid receptor activity were evaluated.

RESULTS

In total, 48/48 and 39/40 subjects completed the single- and multiple-dose studies, respectively. Exposures were generally dose-proportional. The t_max , t_1/2 and CL/F remained unchanged, independent of dose; the respective ranges were 1.5-4.0 h, 22.3-25.1 h, and 4.0-5.2 l h^-1 (multiple-dose study). V_z /F ranged from 136.5 to 283.7 l in the multiple-dose study, and exposure reached steady state by day 4. The mean observed accumulation ratio, by dose, ranged from 1.36-1.98. The urinary Na⁺ /K⁺ ratio increased after single-dose administration; however, its relationship to the doses tested remains unclear. Plasma renin activity, active renin concentration and aldosterone concentration increased dose-dependently. Although blood potassium levels increased dose-dependently in the multiple-dose study (reaching a maximum mean ± standard deviation of 4.63 ± 0.354 mmol l^-1 in the 100-mg group), no safety/tolerability-related problems were detected in either study.

CONCLUSIONS

Exposure levels in healthy adults receiving esaxerenone were generally dose-proportional. Dose-dependent changes in plasma pharmacodynamic biomarkers for the mineralocorticoid receptor were identified during multiple-dose treatment and support the pharmacological activity of esaxerenone. No important safety concerns were identified.

Development and validation of a fast and sensitive UHPLC-ESI-MS method for the simultaneous quantification of spironolactone and its metabolites in ocular tissues

Glucocorticoids are a mainstay for the treatment of immune-mediated conditions and inflammatory diseases. However, their chronic use causes numerous side-effects including delays in corneal and cutaneous wound healing. This is attributed to off-target agonism of the mineralocorticoid receptor, which can be reduced by co-administration of a mineralocorticoid receptor antagonist such as spironolactone. The aim of this study was to develop a fast, selective and sensitive UHPLC-ESI-MS method for the simultaneous quantification of spironolactone, its active metabolites (7α-thiomethylspironolactone and canrenone), the latter's water-soluble prodrug potassium canrenoate and the synthetic glucocorticoid, dexamethasone, in corneal samples (17α-methyltestosterone served as an internal standard). A one-step extraction procedure using MeOH-H₂ O (1:1) was validated and employed to recover the analytes from the corneal tissue. Extracts were centrifuged and the supernatant analyzed under isocratic conditions. Compounds were detected using selected ion recording mode. The method satisfied US Food and Drug Administration guidelines with respect to selectivity, precision and accuracy and displayed linearity from 5 to 1000 ng/mL for all of the analytes. The lower limit of quantitation of the method was 5 ng/mL, making it sufficiently sensitive for quantification of the analytes in samples from in vivo studies.

Targeted treatment of primary aldosteronism - The consensus of Taiwan Society of Aldosteronism

BACKGROUND/PURPOSE

Even with the increasing recognition of primary aldosteronism (PA) as a cause of refractory hypertension and an issue of public health, the consensus of its optimal surgical or medical treatment in Taiwan has not been reached. Our objective was to develop a clinical practice guideline that is feasible for real-world management of PA patients in Taiwan.

METHODS

The Taiwan Society of Aldosteronism (TSA) Task Force recognized the above-mentioned issues and reached this Taiwan PA consensus at its inaugural meeting, in order to provide updated information of internationally acceptable standards, and also to incorporate our local disease characteristics and constraints into PA management.

RESULTS

In patients with lateralized PA, including aldosterone producing adenoma (APA), laparoscopic adrenalectomy is the 'gold standard' of treatment. Mini-laparoscopic and laparoendoscopic single-site approaches are feasible only in highly experienced surgeons. Patients with bilateral adrenal hyperplasia or those not suitable for surgery should be treated by mineralocorticoid receptor antagonists. The outcome data of PA patient management from the literature, especially from PA patients in Taiwan, are reviewed. Mental health screening is helpful in early detection and management of psychopathology among PA patients.

CONCLUSION

We hope this consensus will provide a guideline to help medical professionals to manage PA patients in Taiwan to achieve a better quality of care.

Nonsteroidal mineralocorticoid antagonists in diabetic kidney disease

PURPOSE OF REVIEW

Current data highlight the pathological aspects of excess aldosterone in promoting glomerular hypertrophy, glomerulosclerosis, and proteinuria in diabetic kidney disease (DKD). The role of nonsteroidal mineralocorticoid receptor antagonists (MRAs) in DKD is being evaluated in ongoing clinical trials.

RECENT FINDINGS

Recent studies demonstrate beneficial effects of adding MRAs to the treatment regimen of patients with type 2 diabetes with nephropathy. The MRAs spironolactone and eplerenone can protect against organ damage caused by elevated levels of serum aldosterone in patients with heart failure and DKD but are limited by their side effects, for example, hyperkalemia. Finerenone is more selective for the mineralocorticoid receptor than spironolactone and has greater affinity for the mineralocorticoid receptor than eplerenone. It reduces the concentration of aldosterone without causing significant elevation in serum potassium.

SUMMARY

MRAs have a clear role in reducing albuminuria when used with other renin-angiotensin system blockers in DKD; however, hyperkalemia limits their use. This article provides an overview of clinical studies with a novel MRA, finerenone, and several nonsteroidal MRAs being studied for treatment in DKD.

Pannexin 1 Channels as an Unexpected New Target of the Anti-Hypertensive Drug Spironolactone

RATIONALE

Resistant hypertension is a major health concern with unknown cause. Spironolactone is an effective antihypertensive drug, especially for patients with resistant hypertension, and is considered by the World Health Organization as an essential medication. Although spironolactone can act at the mineralocorticoid receptor (MR; NR3C2), there is increasing evidence of MR-independent effects of spironolactone.

OBJECTIVE

Here, we detail the unexpected discovery that Panx1 (pannexin 1) channels could be a relevant in vivo target of spironolactone.

METHODS AND RESULTS

First, we identified spironolactone as a potent inhibitor of Panx1 in an unbiased small molecule screen, which was confirmed by electrophysiological analysis. Next, spironolactone inhibited α-adrenergic vasoconstriction in arterioles from mice and hypertensive humans, an effect dependent on smooth muscle Panx1, but independent of the MR NR3C2. Last, spironolactone acutely lowered blood pressure, which was dependent on smooth muscle cell expression of Panx1 and independent of NR3C2. This effect, however, was restricted to steroidal MR antagonists as a nonsteroidal MR antagonist failed to reduced blood pressure.

CONCLUSIONS

These data suggest new therapeutic modalities for resistant hypertension based on Panx1 inhibition.

Histone deacetylase inhibition, but not a mineralocorticoid receptor antagonist spironolactone, attenuates atypical transcription by an activating mutant MR (MRS 810L )

A mutation in the mineralocorticoid receptor (MRS 810L ) leads to early-onset hypertension, which is markedly exacerbated during pregnancy. The mutation causes progesterone and even the MR antagonist spironolactone to become potent agonists. Thus, it is hard to control hypertension in patients harbouring this mutation. We hypothesized that histone deacetylase inhibition (HDACi), but not the MR antagonist spironolactone, attenuates atypical transcriptional activity of activating mutant MR (MRS 810L ). We established HEK293T cells overexpressing wild-type MR (MRWT ) or MRS 810L and determined their transcriptional activities by luciferase assay. Expression of MR target genes was measured by quantitative real-time PCR (qRT-PCR). Treatment with aldosterone increased the expression of MR target genes as well as the transcriptional activities in HEK293T cells transfected either with MRWT or MRS 810L . Treatment with either spironolactone or progesterone also increased the expression of MR target genes as well as transcriptional activity, but only in HEK293T cells transfected with MRS 810L . Spironolactone abolished the promoter activity stimulated by aldosterone in HEK293T cells transfected with MRWT . Treatment with HDAC inhibitors attenuated the transcriptional activity as well as the expression of MR target genes induced by aldosterone, spironolactone, or progesterone whether HEK293T cells were transfected with either MRWT or MRS 810L . These results indicate that HDACi, but not an MR antagonist spironolactone, attenuates atypical transcriptional activity of an activating mutant MR (MRS 810L ).

Pharmacologic Considerations for Preexposure Prophylaxis in Transgender Women

Studies of tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC)-based preexposure prophylaxis (PrEP) have not focused on transgendered women who are at disproportionate risk of HIV acquisition. Concerns exist for drug interactions between cross-sex therapy (estradiol, progestins, and spironolactone) with tenofovir disoproxil fumarate-emtricitabine. This review assessed the experimental and theoretical risk for such drug interactions. It was found that none of these medications are implicated as major perpetrators of drug interactions, and the classes use different metabolic pathways for clearance, suggesting a low likelihood for interactions in either direction. Subanalyses of transgender women in Preexposure Prophylaxis Initiative suggested PrEP efficacy if adherence was high. Nevertheless, several research gaps were identified, particularly the need for controlled interaction studies in transgendered women, including effects on renal clearance, intracellular tenofovir diphosphate and emtricitabine triphosphate in target cells, as well as hormone effects on HIV susceptibility and immunity. PrEP should continue to be offered to transgender women while additional research is planned or pending.

30 YEARS OF THE MINERALOCORTICOID RECEPTOR: Mineralocorticoid receptor antagonists: 60 years of research and development

The cDNA of the mineralocorticoid receptor (MR) was cloned 30 years ago, in 1987. At that time, spirolactone, the first generation of synthetic steroid-based MR antagonists (MRAs), which was identified in preclinical in vivo models, had already been in clinical use for 30 years. Subsequent decades of research and development by Searle & Co., Ciba-Geigy, Roussel Uclaf and Schering AG toward identifying a second generation of much more specific steroidal MRAs were all based on the initial 17-spirolactone construct. The salient example is eplerenone, first described in 1987, coincidentally with the cloning of MR cDNA. Its launch on the market in 2003 paralleled intensive drug discovery programs for a new generation of non-steroidal MRAs. Now, 30 years after the cDNA cloning of MR and 60 years of clinical use of steroidal MRAs, novel non-steroidal MRAs such as apararenone, esaxerenone and finerenone are in late-stage clinical trials in patients with heart failure, chronic kidney disease (CKD), hypertension and liver disease. Finerenone has already been studied in over 2000 patients with heart failure plus chronic kidney disease and/or diabetes, and in patients with diabetic kidney disease, in five phase II clinical trials. Here, we reflect on the history of the various generations of MRAs and review characteristics of the most important steroidal and non-steroidal MRAs.

True rate of mineralocorticoid receptor antagonists-related hyperkalemia in placebo-controlled trials: A meta-analysis

BACKGROUND

Mineralocorticoid receptor antagonists (MRA) improve survival in heart failure with reduced ejection fraction but are often underused, mostly due to concerns of hyperkalemia. Because hyperkalemia occurs also on placebo, we aimed to determine the truly MRA-related rate of hyperkalemia.

METHODS

We performed a meta-analysis including randomized, placebo-controlled trials reporting hyperkalemia on MRAs in patients after myocardial infarction or with chronic heart failure. We evaluated the truly MRA-related rate of hyperkalemia that represents hyperkalemia on MRA, corrected for hyperkalemia on placebo (Pla), according to the equation: True MRA (%)=(MRA (%) - Pla (%))/MRA (%).

RESULTS

A total number of 16,065 patients from 7 trials were analyzed. Hyperkalemia was more frequently observed on MRA (9.3%) vs placebo (4.3%) (risk ratio 2.17, 95% CI 1.92-2.45, P<.0001). Truly MRA-related hyperkalemia was 54%, whereas 46% were non-MRA related. In trials using eplerenone, hyperkalemia was documented in 5.0% on eplerenone and in 2.6% on placebo (P<.0001). In spironolactone trials, hyperkalemia was documented in 17.5% and in 7.5% of patients on placebo (P=.0001). Hypokalemia occurred less frequently in patients on MRA (9.3%) compared with placebo (14.8%) (risk ratio 0.58, CI 0.47-0.72, P<.0001).

CONCLUSION

This meta-analysis shows that in clinical trials, 54% of hyperkalemia cases were specifically related to the MRA treatment and 46% to other reasons. Therefore, non-MRA-related rises in potassium levels might be underestimated and should be rigorously explored before cessation of the evidence-based therapy with MRAs.

Steroidal and Novel Non-steroidal Mineralocorticoid Receptor Antagonists in Heart Failure and Cardiorenal Diseases: Comparison at Bench and Bedside

Characterization of mice with cell-specific deletion or overexpression of the mineralocorticoid receptor (MR) shed a new light on its role in health and disease. Pathophysiological MR activation contributes to a plethora of deleterious molecular mechanisms in the development of cardiorenal diseases like chronic kidney disease (CKD) and heart failure (HF). Accordingly, the available steroidal MR antagonists (MRAs) spironolactone (first generation MRA) and eplerenone (second generation MRA) have been shown to be effective in reducing cardiovascular (CV) mortality and morbidity in patients with chronic HF and a reduced left ventricular ejection fraction (HFrEF). However, they remain underutilized, in large part owing to the risk inducing severe adverse events including hyperkalemia and worsening of kidney function, particularly when given on top of inhibitors of the renin angiotensin system (RAS) to patients with concomitant kidney dysfunction. Novel, potent, and selective non-steroidal MRAs (third generation) were identified in drug discovery campaigns and a few entered clinical development recently. One of these is finerenone with different physicochemical, pharmacokinetics, and pharmacological properties in comparison with the steroidal MRAs. Available data from five clinical phase II trials with finerenone in more than 2,000 patients with HF and additional CKD and/or diabetes as well as in patients with diabetic kidney disease demonstrated that neither hyperkalemia nor reductions in kidney function were limiting factors to its use. Moreover, finerenone demonstrated a nominally improved outcome compared to eplerenone in a phase IIb trial with 1,066 patients with HFrEF and concomitant type 2 diabetes mellitus (T2DM) and/or CKD.