Glucocorticoid-mediated mineralocorticoid receptor activation and hypertension

Lysine-Cysteine-Serine-Tryptophan Inserted into the DNA-Binding Domain of Human Mineralocorticoid Receptor Increases Transcriptional Activation by Aldosterone

Due to alternative splicing in an ancestral DNA-binding domain (DBD) of the mineralocorticoid receptor (MR), humans contain two almost identical MR transcripts with either 984 amino acids (MR-984) or 988 amino acids (MR-988), in which their DBDs differ by only four amino acids, Lys,Cys,Ser,Trp (KCSW). Human MRs also contain mutations at two sites, codons 180 and 241, in the amino terminal domain (NTD). Together, there are five distinct full-length human MR genes in GenBank. Human MR-984, which was cloned in 1987, has been extensively studied. Human MR-988, cloned in 1995, contains KCSW in its DBD. Neither this human MR-988 nor the other human MR-988 genes have been studied for their response to aldosterone and other corticosteroids. Here, we report that transcriptional activation of human MR-988 by aldosterone is increased by about 50% compared to activation of human MR-984 in HEK293 cells transfected with the TAT3 promoter, while the half-maximal response (EC50) is similar for aldosterone activation of MR-984 and MR-988. Transcriptional activation of human MR also depends on the amino acids at codons 180 and 241. Interestingly, in HEK293 cells transfected with the MMTV promoter, transcriptional activation by aldosterone of human MR-988 is similar to activation of human MR-984, indicating that the promoter has a role in the regulation of the response of human MR-988 to aldosterone. The physiological responses to aldosterone and other corticosteroids in humans with MR genes containing KCSW and with differences at codons 180 and 241 in the NTD warrant investigation.

Drug development and potential targets for Cushing's syndrome

Cushing's syndrome (CS) is a complex disorder characterized by the excessive secretion of cortisol, with Cushing's disease (CD), particularly associated with pituitary tumors, exhibiting heightened morbidity and mortality. Although transsphenoidal pituitary surgery (TSS) stands as the primary treatment for CD, there is a crucial need to optimize patient prognosis. Current medical therapy serves as an adjunctive measure due to its unsatisfactory efficacy and unpredictable side effects. In this comprehensive review, we delve into recent advances in understanding the pathogenesis of CS and explore therapeutic options by conducting a critical analysis of potential drug targets and candidates. Additionally, we provide an overview of the design strategy employed in previously reported candidates, along with a summary of structure-activity relationship (SAR) analyses and their biological efficacy. This review aims to contribute valuable insights to the evolving landscape of CS research, shedding light on potential avenues for therapeutic development.

Endocrine causes of hypertension: literature review and practical approach

Hypertension (HTN) affects more than 30% of adults worldwide. It is the most frequent modifiable cardiovascular (CV) risk factor, and is responsible for more than 10 million death every year. Among patients with HTN, we usually distinguish secondary HTN, that is HTN due to an identified cause, and primary HTN, in which no underlying cause has been found. It is estimated that secondary hypertension represents between 5 and 15% of hypertensive patients [1]. Therefore, routine screening of patients for secondary HTN would be too costly and is not recommended. In addition to the presence of signs suggesting a specific secondary cause, screening is based on specific criteria. Identifying secondary HTN can be beneficial for patients in certain situations, because it may lead to specific treatments, and allow better control of blood pressure and sometimes even a cure. Besides, it is now known that secondary HTN are more associated with morbidity and mortality than primary HTN. The main causes of secondary HTN are endocrine and renovascular (mainly due to renal arteries abnormalities). The most frequent endocrine cause is primary aldosteronism, which diagnosis can lead to specific therapies. Pheochromocytoma and Cushing syndrome also are important causes, and can have serious complications. Other causes are less frequent and can be suspected on specific situations. In this article, we will describe the endocrine causes of HTN and discuss their treatments.

Bio-Inspired Molecularly Imprinted Polymer Electrochemical Sensor for Cortisol Detection Based on O-Phenylenediamine Optimization

This paper presents a comprehensive investigation of the various parameters involved in the fabrication of a molecularly imprinted polymer (MIP) sensor for the detection of cortisol. Parameters such as monomer concentration, electropolymerization cycles, pH, monomer-template ratio, template removal technique, and rebinding time were optimized to establish a more consistent and effective method for the fabrication of MIP sensors. Under the optimized conditions, the MIP sensor demonstrated a proportional decrease in differential pulse voltammetry peak currents with increasing cortisol concentration in the range of 0.1 to 100 nM. The sensor exhibited excellent sensitivity, with a limit of detection of 0.036 nM. Selectivity experiments using a non-imprinted polymer sensor confirmed the specific binding affinity of the MIP sensor for cortisol, distinguishing it from other steroid hormones. This study provides crucial insights into the development of a reliable and sensitive strategy for cortisol detection using O-PD-based MIPs. These findings laid the foundation for further advancements in MIP research.

The circadian clock remains intact, but with dampened hormonal output in heart failure

BACKGROUND

Circadian (24-h) rhythms are important regulators in physiology and disease, but systemic disease may disrupt circadian rhythmicity. Heart failure (HF) is a systemic disease affecting hormonal regulation. We investigate whether HF affects the rhythmic expression of melatonin and cortisol, main endocrine products of the central clock, and cardiac-specific troponin in patients. We corroborate the functionality of the peripheral clock directly in the organs of translational models, inaccessible in human participants.

METHODS

We included 46 HF patients (71.7% male, median age of 60 years, NYHA class II (32.6%) or III (67.4%), ischemic cardiomyopathy (43.5%), comorbidities: diabetes 21.7%, atrial fibrillation 30.4%), and 24 matched controls. Blood was collected at seven time-points during a 24-h period (totalling 320 HF and 167 control samples) for melatonin, cortisol, and cardiac troponin T (cTnT) measurements after which circadian rhythms were assessed through cosinor analyses, both on the individual and the group level. Next, we analysed peripheral circadian clock functionality using cosinor analysis in male animal HF models: nocturnal mice and diurnal zebrafish, based on expression of core clock genes in heart, kidneys, and liver, every 4 h during a 24-h period in a light/darkness synchronised environment.

FINDINGS

Melatonin and cortisol concentrations followed a physiological 24-h pattern in both patients and controls. For melatonin, acrophase occurred during the night for both groups, with significantly decreased amplitude (median 5.2 vs 8.8, P = 0.0001) and circadian variation ([maximum]/[minimum]) in heart failure patients. For cortisol, mesor showed a significant increase for HF patients (mean 331.9 vs 275.1, P = 0.017) with a difference of 56.8 (95% CI 10.3-103.3) again resulting in a relatively lower variation: median 3.9 vs 6.3 (P = 0.0058). A nocturnal blood pressure dip was absent in 77.8% of HF patients. Clock gene expression profiles (Bmal, Clock, Per, Cry) were similar and with expected phase relations in animal HF models and controls, demonstrating preserved peripheral clock functionality in HF. Furthermore, oscillations in diurnal zebrafish were expectedly in opposite phases to those of nocturnal mice. Concordantly, cTnT concentrations in HF patients revealed significant circadian oscillations.

INTERPRETATION

Central clock output is dampened in HF patients while the molecular peripheral clock, as confirmed in animal models, remains intact. This emphasises the importance of taking timing into account in research and therapy for HF, setting the stage for another dimension of diagnostic, prognostic and therapeutic approaches.

FUNDING

Hartstichting.

Glucocorticoid-induced thrombotic microangiopathy in paroxysmal nocturnal hemoglobinuria: A case report and review of literature

BACKGROUND

Thrombotic microangiopathy (TMA) is a group of disorders that converge on excessive platelet aggregation in the microvasculature, leading to consumptive thrombocytopenia, microangiopathic hemolysis and ischemic end-organ dysfunction. In predisposed patients, TMA can be triggered by many environmental factors. Glucocorticoids (GCs) can compromise the vascular endothelium. However, GC-associated TMA has rarely been reported, which may be due to the lack of awareness of clinicians. Given the high frequency of thrombocytopenia during GC treatment, particular attention should be given to this potentially fatal complication.

CASE SUMMARY

An elderly Chinese man had a 12-year history of aplastic anemia (AA) and a 3-year history of paroxysmal nocturnal hemoglobinuria (PNH). Three months earlier, methylprednisolone treatment was initiated at 8 mg/d and increased to 20 mg/d to alleviate complement-mediated hemolysis. Following GC treatment, his platelet counts and hemoglobin levels rapidly decreased. After admission to our hospital, the dose of methylprednisolone was increased to 60 mg/d in an attempt to enhance the suppressive effect. However, increasing the GC dose did not alleviate hemolysis, and his cytopenia worsened. Morphological evaluation of the marrow smears revealed increased cellularity with an increased percentage of erythroid progenitors without evident dysplasia. Cluster of differentiation (CD)55 and CD59 expression was significantly decreased on erythrocytes and granulocytes. In the following days, platelet transfusion was required due to severe thrombocytopenia. Observation of platelet transfusion refractoriness indicated that the exacerbated cytopenia may have been caused by the development of TMA due to GC treatment because the transfused platelet concentrates had no defects in glycosylphosphatidylinositol-anchored proteins. We examined blood smears and found a small number of schistocytes, dacryocytes, acanthocytes and target cells. Discontinuation of GC treatment resulted in rapidly increased platelet counts and steady increases in hemoglobin levels. The patient’s platelet counts and hemoglobin levels returned to the levels prior to GC treatment 4 weeks after GC discontinuation.

CONCLUSION

GCs can drive TMA episodes. When thrombocytopenia occurs during GC treatment, TMA should be considered, and GCs should be discontinued.

Discovery and Optimization of N-Acyl-6-sulfonamide-tetrahydroquinoline Derivatives as Novel Non-Steroidal Selective Glucocorticoid Receptor Modulators

Selective glucocorticoid receptor modulators (SGRMs), which can dissociate the transactivation from the transrepression of the glucocorticoid receptor (GR), are regarded as very promising therapeutics for inflammatory and autoimmune diseases. We previously discovered a SGRM HP-19 based on the passive antagonistic conformation of GR and bioassays. In this study, we further analyzed the dynamic changes of the passive antagonistic state upon the binding of HP-19 and designed and synthesized 62 N-acyl-6-sulfonamide-tetrahydroquinoline derivatives by structural optimization of HP-19. Therein, compound B53 exhibits the best transrepression activity (IC_{50 NF-κB} = 0.009 ± 0.001 μM) comparable with dexamethasone (IC_{50 NF-κB} = 0.005 ± 0.001 μM) and no transactivation activity. B53 can efficiently reduce the expression of inflammatory factors IL-6, IL-1β, TNF-α, and so on and makes a milder adverse effect and is highly specific to GR. Furthermore, B53 is able to significantly relieve dermatitis on a mouse model via oral drug intervention.

Investigation of the Influence of Various Functional Groups on the Dynamics of Glucocorticoids

The basic configuration of glucocorticoid consists of four-fused rings associated with one cyclohexadienone ring, two cyclohexane rings, and one cyclopentane ring. The ways the structure and dynamics of five glucocorticoids (prednisone, prednisolone, prednisolone acetate, methylprednisolone, and methylprednisolone acetate) are altered because of the substitution of various functional groups with these four-fused rings are studied thoroughly by applying sophisticated solid-state nuclear magnetic resonance (NMR) methodologies. The biological activities of these glucocorticoids are also changed because of the attachment of various functional groups with these four-fused rings. The substitution of the hydroxyl group (with the C11 atom of the cyclohexane ring) in place of the keto group enhances the potential of the glucocorticoid to cross the cellular membrane. As a result, the bioavailability of prednisolone (the hydroxyl group is attached with the C11 atom of the cyclohexane ring) is increased compared to prednisone (the keto group is attached with the C11 atom of cyclohexane rings). Another notable point is that the spin-lattice relaxation rate at crystallographically distinct carbon nuclei sites of prednisolone is increased compared to that of the prednisone, which implies that the motional degrees of freedom of glucocorticoid is increased because of the substitution of the hydroxyl group in place of the keto group of the cyclohexane ring. The attachment of the methyl group with the C6 atom of cyclohexane rings further reduces the spin-lattice relaxation time at crystallographically distinct carbon nuclei sites of glucocorticoid and its bioactivity is also increased. By comparing the spin-lattice relaxation time and the local correlation time at crystallographically different carbon nuclei sites of three steroids prednisone, prednisolone, and methylprednisolone, it is observed that both the spin-lattice relaxation time and the local correlation time gradually decrease at each crystallographically distinct carbon nuclei sites when we move from prednisone to prednisolone to methyl-prednisolone. On the other hand, if we compare the same for prednisolone, prednisolone acetate, and methylprednisolone acetate, then we also observe that both the spin-lattice relaxation time and the local-correlation time gradually decrease from prednisolone to prednisolone acetate to methylprednisolone acetate for all chemically different carbon nuclei. It is also noticeable that both the spin-lattice relaxation time and the local-correlation time gradually decrease from prednisone to prednisolone to prednisolone acetate to methylprednisolone to methylprednisolone acetate for most of the carbon nuclei sites. From in silico analysis, it is also revealed that the bioavailability and efficacy of the glucocorticoid increase from prednisone to prednisolone to prednisolone acetate to methylprednisolone to methylprednisolone acetate. Hence, it can be concluded that the biological activity and the motional degrees of freedom of the glucocorticoids are highly correlated. These types of studies provide a clear picture of the structure-activity relationship of the drug molecules, which will enlighten the path of developing highly potent glucocorticoids with minimum side effects. Another important aspect of these types of studies is to provide information about the electronics configuration and nuclear spin dynamics at crystallographically different carbon nuclei sites of five glucocorticoids, which will enrich the field of "NMR crystallography".

Torsade de pointes in an older patient with Takotsubo cardiomyopathy caused by licorice‐induced pseudoaldosteronism: A case report

Takotsubo cardiomyopathy (TCM) causes QT interval prolongation, potentially leading to a fatal arrhythmia. We report the first case of TCM associated with licorice‐induced pseudoaldosteronism causing fatal arrhythmia in an older patient on polypharmacy including yokukansan (TJ‐54) and galantamine. Polypharmacy should be resolved to prevent unexpected adverse events in older patients.

Discovery of a novel nonsteroidal selective glucocorticoid receptor modulator by virtual screening and bioassays

Synthetic glucocorticoids (GCs) have been widely used in the treatment of a broad range of inflammatory diseases, but their clinic use is limited by undesired side effects such as metabolic disorders, osteoporosis, skin and muscle atrophies, mood disorders and hypothalamic-pituitary-adrenal (HPA) axis suppression. Selective glucocorticoid receptor modulators (SGRMs) are expected to have promising anti-inflammatory efficacy but with fewer side effects caused by GCs. Here, we reported HT-15, a prospective SGRM discovered by structure-based virtual screening (VS) and bioassays. HT-15 can selectively act on the NF-κB/AP1-mediated transrepression function of glucocorticoid receptor (GR) and repress the expression of pro-inflammation cytokines (i.e., IL-1β, IL-6, COX-2, and CCL-2) as effectively as dexamethasone (Dex). Compared with Dex, HT-15 shows less transactivation potency that is associated with the main adverse effects of synthetic GCs, and no cross activities with other nuclear receptors. Furthermore, HT-15 exhibits very weak inhibition on the ratio of OPG/RANKL. Therefore, it may reduce the side effects induced by normal GCs. The bioactive compound HT-15 can serve as a starting point for the development of novel therapeutics for high dose or long-term anti-inflammatory treatment.

Aldosterone and dexamethasone activate African lungfish mineralocorticoid receptor: Increased activation after removal of the amino-terminal domain

Aldosterone, the main physiological mineralocorticoid in humans and other terrestrial vertebrates, first appears in lungfish, which are lobe-finned fish that are forerunners of terrestrial vertebrates. Aldosterone activation of the MR regulates internal homeostasis of water, sodium and potassium, which was critical in the conquest of land by vertebrates. We studied transcriptional activation of the slender African lungfish MR by aldosterone, other corticosteroids and progesterone and find that aldosterone, 11-deoxycorticosterone, 11-deoxycortisol and progesterone have half-maximal responses (EC50 s) below 1 nM and are potential physiological mineralocorticoids. In contrast, EC50 s for corticosterone and cortisol were 23 nM and 66 nM, respectively. Unexpectedly, truncated lungfish MR, consisting of the DNA-binding, hinge and steroid-binding domains, had a stronger response to corticosteroids and progesterone than full-length lungfish MR, indicating that the N-terminal domain represses steroid activation of lungfish MR, unlike human MR in which the N-terminal domain contains an activation function. BLAST searches of GenBank did not retrieve a GR ortholog, leading us to test dexamethasone and triamcinolone for activation of lungfish MR. At 10 nM, both synthetic glucocorticoids are about 4-fold stronger than 10 nM aldosterone in activating full-length lungfish MR, leading us to propose that lungfish MR also functions as a GR.

Adrenocorticotropic hormone: An expansion of our current understanding of the treatment for nephrotic syndrome

In clinical practice, we may encounter a treatment dilemma where in some patients with nephrotic syndrome are resistant to glucocorticoids or immunosuppressive agents. Thus, we currently lack viable treatment options and eagerly await the availability of new drugs. Adrenocorticotropic hormone (ACTH) had earlier been used to treat nephrotic syndrome in children, but has now become less popular owing to the advent of oral glucocorticoids. However, in recent studies, ACTH was reportedly used again for treating nephrotic syndrome, reducing proteinuria and protecting renal function, indicating a possibility for its use in the treatment of refractory nephrotic syndrome. This review analysed the validity of ACTH in these studies, focusing on the mechanism of action, application in both paediatric and adult patients with nephrotic syndrome, particularly in children, and possible side effects. We anticipate that our findings will help clinicians in treatment decision-making.

A novel mineralocorticoid receptor antagonist, 7,3',4'-trihydroxyisoflavone improves skin barrier function impaired by endogenous or exogenous glucocorticoids

Excess glucocorticoids (GCs) with either endogenous or exogenous origins deteriorate skin barrier function. GCs bind to mineralocorticoid and GC receptors (MRs and GRs) in normal human epidermal keratinocytes (NHEKs). Inappropriate MR activation by GCs mediates various GC-induced cutaneous adverse events. We examined whether MR antagonists can ameliorate GC-mediated skin barrier dysfunction in NHEKs, reconstructed human epidermis (RHE), and subjects under psychological stress (PS). In a preliminary clinical investigation, topical MR antagonists improved skin barrier function in topical GC-treated subjects. In NHEKs, cortisol induced nuclear translocation of GR and MR, and GR and MR antagonists inhibited cortisol-induced reductions of keratinocyte differentiation. We identified 7,3',4'-trihydroxyisoflavone (7,3',4'-THIF) as a novel compound that inhibits MR transcriptional activity by screening 30 cosmetic compounds. 7,3',4'-THIF ameliorated the cortisol effect which decreases keratinocyte differentiation in NHEKs and RHE. In a clinical study on PS subjects, 7,3',4'-THIF (0.1%)-containing cream improved skin barrier function, including skin surface pH, barrier recovery rate, and stratum corneum lipids. In conclusion, skin barrier dysfunction owing to excess GC is mediated by MR and GR; thus, it could be prevented by treatment with MR antagonists. Therefore, topical MR antagonists are a promising therapeutic option for skin barrier dysfunction after topical GC treatment or PS.

JTP-117968, a novel selective glucocorticoid receptor modulator, exhibits significant anti-inflammatory effect while maintaining bone mineral density in mice

Classic glucocorticoids have been prescribed for various inflammatory diseases, such as rheumatoid arthritis, due to their outstanding anti-inflammatory effects. However, glucocorticoids cause numerous unwanted side effects, including osteoporosis and diabetes. Hence, selective glucocorticoid receptor modulators (SGRMs), which retain anti-inflammatory effects with minimized side effects, are among the most anticipated drugs in the clinical field. The assumption is that there are two major mechanisms of action via glucocorticoid receptors, transrepression (TR) and transactivation (TA). In general, anti-inflammatory effects of glucocorticoids are largely due to TR, while the side effects associated with glucocorticoids are mostly mediated through TA. We previously reported that JTP-117968, a novel SGRM, maintained partial TR activity while remarkably reducing the TA activity. In this study, we investigated the anti-inflammatory effect of JTP-117968 on a lipopolysaccharide (LPS) challenge model and collagen-induced arthritis (CIA) model in mice. Meanwhile, we tested the effect of JTP-117968 on the bone mineral density (BMD) in mouse femur to evaluate the side effect. Based on the evaluation, JTP-117968 reduced the plasma levels of tumor necrosis factor α induced by LPS challenge in mice significantly. Remarkably, CIA development was suppressed by JTP-117968 comparably with prednisolone and PF-802, an active form of fosdagrocorat that has been developed clinically as an orally available SGRM. Strikingly, the side effect of JTP-117968 on mouse femoral BMD was much lower than those of PF-802 and prednisolone. Therefore, JTP-117968 has attractive potential as a new therapeutic option against inflammatory diseases with minimized side effects compared to classic glucocorticoids.

Possible value of galectin-3 on follow-up of cardiac remodeling during glucocorticoid treatment

Glucocorticoids are among the most prescribed drugs globally due to their potent anti-inflammatory and immunosuppressive properties. Although they have positive effects on the treatment of various disease states; long-term administration is associated with high blood pressure, insulin resistance, and susceptibility to type 2 diabetes. The heart attempts to cope with increased blood pressure and a decrease in glucose utilization by developing pathological cardiac remodeling. However, in this process, cardiac fibrosis formation and deterioration in heart structure and functions occur. Galectin-3, a member of the β-galactoside binding lectins, is consistently associated with inflammation and fibrosis in the pathogenesis of various disease states including insulin resistance and heart failure. Galectin-3 expression is markedly increased in activated macrophages and a subset of activated fibroblasts and vascular cells. Also, failing and remodeling myocardium show increased Gal-3 expression and elevated Gal-3 levels are related to heart failure severity and prognosis. Furthermore, Gal-3-related pathways are recently suggested as therapeutic targets both pharmacologically and genetically to increase insulin sensitivity in vivo. The objective of this review is to provide a summary of our current understanding of the role of glucocorticoid-associated insulin resistance, which is important for some cardiac events, and the potential role of galectin in this pathophysiological process.

Long-term administration of prednisolone: Effects on the myocardial tissue of healthy beagle dogs

This study aimed to assess the structural and functional effects of long-term hyperglucocorticoidemia on canine myocardium and compare these parameters with histopathological changes. Twelve healthy male beagle dogs were enrolled and assigned to the high-dose prednisolone (P; n=6) and control (C; n=6) groups. The P group was treated with 2 mg/kg of prednisolone BID for 84 days. Clinical parameters were measured using echocardiography and non-invasive systolic blood pressure (SBP) measured before the initiation of synthetic corticosteroids and at 7, 28, 56, and 84 days after the start of medication. For histological evaluation, cardiovascular tissue was harvested from dogs in groups P (at the end of the medication period) and C (scheduled to be euthanized for unrelated reasons). In the P group, clinical changes including thickening of the left ventricular free wall (LVFW) and interventricular septum (IVS), decreased left ventricular (LV) diastolic function, and increased SBP were observed after the start of medication. During histological evaluation, fibrosis was observed in the LVFW and IVS in the P group. Furthermore, decreased glucocorticoid receptor (GCR) levels were observed in the LVFW, right ventricular free wall (RVFW), and IVS and increased mineralocorticoid receptor (MCR) levels were observed in the LVFW and RVFW in the P group compared with those in the C group. In conclusion, fibrosis may cause LV structural and functional abnormalities in dogs with hyperadrenocorticism. Furthermore, GCR downregulation and upregulated MCR might influence the myocardial fibrosis.

Novel antihypertensive action of rutin is mediated via inhibition of angiotensin converting enzyme/mineralocorticoid receptor/angiotensin 2 type 1 receptor (ATR1) signaling pathways in uninephrectomized hypertensive rats

Hypertension is the most common cardiovascular disease that affects approximately 26% of adult population, worldwide. Rutin is one of the important flavonoids that is consumed in the daily diet, and found in many food items, vegetables, and beverages. Uninephrectomy (UNX) of the left kidney was performed, followed by induction of hypertension. The rats were randomly divided into four groups of 10 rats: group 1-Sham-operated rats; group 2-UNX rats, group 3-UNX-L-NAME (40 mg/kg) plus rutin (100 mg/kg bwt), and groups 4-UNX-L-NAME plus lisinopril (10 mg/kg bwt), orally for 3 weeks. Results revealed significant heightening of arterial pressure and oxidative stress indices, while hypertensive rats treated with rutin had lower expressions of angiotensin converting enzyme (ACE) and mineralocorticoid receptor in uninephrectomized rats. Together, rutin as a novel antihypertensive flavonoid could provide an unimaginable benefits for the management of hypertension through inhibition of angiotensin converting enzyme and mineralocorticoid receptor. PRACTICAL APPLICATIONS: Hypertension has been reported to be the most common cardiovascular disease, affecting approximately 26% of the adult population worldwide with predicted prevalence to increase by 60% by 2025. Recent advances in phytomedicine have shown flavonoids to be very helpful in the treatment of many diseases. Flavonoids have been used in the treatment and management of cardiovascular diseases, obesity and hypertension. The study revealed that rutin, a known flavonoid inhibited angiotensin converting enzyme (ACE), angiotensin 2 type 1 receptor (ATR1), and mineralocorticoid receptor (MCR), comparable to the classic ACE inhibitor, Lisinopril, indicating the novel antihypertensive property of rutin. Therefore, flavonoids such as rutin found in fruits and vegetables could, therefore, serve as an antihypertensive drug regimen. Combining all, functional foods rich in flavonoids could be used as potential therapeutic candidates for managing uninephrectomized hypertensive patients.

Detrimental effects of hypercortisolism on brain structure and related risk factors

Brain structural abnormalities are often observed on magnetic resonance imaging (MRI) scans of Cushing's syndrome patients, but the pathogenesis is not fully understood. To understand the relationship between brain structural abnormalities and potential risk factors in active Cushing's disease (CD) patients, a total of 101 treatment-naïve CD patients and 95 sex-, age- and education matched controls with non-functioning adenomas (NFA) underwent clinical evaluation and MRI investigation, and the relative risk factors were analyzed. 14 patients in sustained remission after transsphenoidal surgery were followed. Compared with the NFA subjects, the patients with CD had more cortical (P < 0.01) and subcortical atrophy (P < 0.01) and a higher prevalence of white matter hyperintensity (WMH) (P < 0.01). WMH severity in CD patients positively correlated with age (r = 0.532, P = 0.000), disease course (r = 0.257, P = 0.009), postprandial glucose (r = 0.278, P = 0.005), frequency of left ventricular hypertrophy (r = 0.398, P = 0.001) and hypothyroidism (r = 0.246, P = 0.014). The markers of cortical and subcortical atrophy (sylvian fissure ratio, bifrontal ratio, bicaudate ratio and third ventricle width) were positively associated with the progression of WMH in the CD patients. In the follow-up of 14 patients with CD, brain atrophy and WMH was partially reversible after correction of hypercortisolism. In conclusions, brain atrophy and WMH were more likely to appear in CD patients and were possibly partially reversible following correction of hypercortisolism.

Glucocorticoid receptor-IRS-1 axis controls EMT and the metastasis of breast cancers

Glucocorticoid receptor (GR) is involved in the transcriptional regulation of genes that are important for various biological functions, including tumor growth and metastatic progression. However, the cellular and biological effects of GR remain poorly understood. Here, we investigated the role of GR and its underlying mechanism in mediating breast cancer cell survival and metastasis. We observed that the GR levels were increased in drug-resistant breast cancer cells and in metastatic breast cancer samples. GR promoted tumor cell invasion and lung metastasis in vivo. The GR expression levels were negatively correlated with the survival rates of breast cancer patients. Both ectopic expression and knockdown of GR revealed that GR is a strong inducer of epithelial-to-mesenchymal transition (EMT), which is consistent with its effects on cell survival and metastasis. GR suppressed the expression of insulin receptor substrate 1 (IRS-1) by acting as an IRS-1 transcriptional repressor. In addition, GR has an opposite effect on the expression levels of IRS-2, indicating that GR is able to differentially regulate the IRS-1 and IRS-2 expression. The cellular and biological effects elicited by GR were consistent with the reduced levels of IRS-1 observed in cancer cells, and GR-mediated IRS-1 suppression activated the ERK2 MAP kinase pathway, which is required for GR-mediated EMT. Taken together, our results indicate that GR–IRS-1 signaling axis plays an essential role in regulating the survival, invasion, and metastasis of breast cancer cells.

Chronic stress and endothelial dysfunction: mechanisms, experimental challenges, and the way ahead

Although chronic stress is an important risk factor for cardiovascular diseases (CVD) onset, the underlying mechanisms driving such pathophysiological complications remain relatively unknown. Here, dysregulation of innate stress response systems and the effects of downstream mediators are strongly implicated, with the vascular endothelium emerging as a primary target of excessive glucocorticoid and catecholamine action. Therefore, this review article explores the development of stress-related endothelial dysfunction by focusing on the following: 1) assessing the phenomenon of stress and complexities surrounding this notion, 2) discussing mechanistic links between chronic stress and endothelial dysfunction, and 3) evaluating the utility of various preclinical models currently employed to study mechanisms underlying the onset of stress-mediated complications such as endothelial dysfunction. The data reveal that preclinical models play an important role in our efforts to gain an increased understanding of mechanisms underlying stress-mediated endothelial dysfunction. It is our understanding that this provides a good foundation going forward, and we propose that further efforts should be made to 1) more clearly define the concept of stress and 2) standardize protocols of animal models with specific guidelines to better indicate the mental complications that are simulated.

Glucocorticoid and mineralocorticoid receptors and corticosteroid homeostasis are potential targets for endocrine-disrupting chemicals

Endocrine-disrupting chemicals (EDCs) have received significant concern, since they ubiquitously exist in the environment and are able to induce adverse health effects on human and wildlife. Increasing evidence shows that the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), members of the steroid receptor subfamily, are potential targets for EDCs. GR and MR mediate the actions of glucocorticoids and mineralocorticoids, respectively, which are two main classes of corticosteroids involved in many physiological processes. The effects of EDCs on the homeostasis of these two classes of corticosteroids have also gained more attention recently. This review summarized the effects of environmental GR/MR ligands on receptor activity, and disruption of corticosteroid homeostasis. More than 130 chemicals classified into 7 main categories were reviewed, including metals, metalloids, pesticides, bisphenol analogues, flame retardants, other industrial chemicals and pharmaceuticals. The mechanisms by which EDCs interfere with GR/MR activity are primarily involved in ligand-receptor binding, nuclear translocation of the receptor complex, DNA-receptor binding, and changes in the expression of endogenous GR/MR genes. Besides directly interfering with receptors, enzyme-catalyzed synthesis and prereceptor regulation pathways of corticosteroids are also important targets for EDCs. The collected evidence suggests that corticosteroids and their receptors should be considered as potential targets for safety assessment of EDCs. The recognition of relevant xenobiotics and their underlying mechanisms of action is still a challenge in this emerging field of research.

Development of highly potent glucocorticoids for steroid-resistant severe asthma

Clinical application of inhaled glucocorticoids (GCs) has been hampered in the case of steroid-resistant severe asthma. To overcome this limitation, we have developed a series of highly potent GCs, including VSGC12, VSG158, and VSG159 based on the structural insight into the glucocorticoid receptor (GR). Particularly, VSG158 exhibits a maximal repression of lung inflammation and is 10 times more potent than the currently most potent clinical GC, Fluticasone Furoate (FF), in a murine model of asthma. More importantly, VSG158 displays a unique property to reduce neutrophilic inflammation in a steroid-resistant airway inflammation model, which is refractory to clinically available GCs, including dexamethasone and FF. VSG158 and VSG159 are able to deliver effective treatments with reduced off-target and side effects. In addition, these GCs also display pharmacokinetic properties that are suitable for the inhalation delivery method for asthma treatment. Taken together, the excellent therapeutic and side-effect profile of these highly potent GCs holds promise for treating steroid-resistant severe asthma.

Hypertension in Childhood Nephrotic Syndrome

Arterial hypertension (HTN) is commonly encountered by clinicians treating children with steroid sensitive (SSNS) and steroid resistant nephrotic syndrome (SRNS). Although the prevalence of HTN in SSNS is less documented than in SRNS, recent studies reported high prevalence in both. Studies have estimated the prevalence of HTN in different patient populations with NS to range from 8 to 59.1%. Ambulatory HTN, abnormalities in BP circadian rhythm, and measures of BP variability are prevalent in patients with NS. Multiple mechanisms and co-morbidities contribute to the pathophysiology of HTN in children with NS. Some contributing factors are known to cause acute and episodic elevations in blood pressure such as fluid shifts, sodium retention, and medication side effects (steroids, CNIs). Others are associated with chronic and more sustained HTN such as renal fibrosis, decreased GFR, and progression of chronic kidney disease. Children with NS are more likely to suffer from other cardiovascular disease risk factors, such as obesity, increased measures of arterial stiffness [increased carotid intima-media thickness (cIMT), endothelial dysfunction, increased pulse wave velocity (PWV)], impaired glucose metabolism, dyslipidemia, left ventricular hypertrophy (LVH), left ventricular dysfunction, and atherosclerosis. Those risk factors have been associated with premature death in adults. In this review on HTN in patients with NS, we will discuss the epidemiology and pathophysiology of hypertension in patients with NS, as well as management aspects of HTN in children with NS.

Monogene Formen der arteriellen Hypertonie

Hintergrund

Die Grundlage der arteriellen Hypertonie bei der überwiegenden Mehrzahl der Patienten ist multifaktorieller, zum großen Teil umweltbedingter Genese und derzeit in der Routinediagnostik nicht sinnvoll molekulargenetisch untersuchbar. Bei einem kleinen Teil der Patienten (<1 %) ist die arterielle Hypertonie aber Folge hereditärer, monogener Defekte. Hierzu gehören das Liddle-Syndrom, familiärer Hyperaldosteronismus, apparenter Mineralkortikoidexzess und Pseudohypoaldosteronismus. Diese und andere hereditäre Hypertonien gehen pathomechanistisch auf Störungen in den renalen Regelkreisen der Elektrolyt- und Volumenhomöostase zurück.

Ziel der Arbeit

Die bekannten Typen der hereditären Hypertonien sollen verständlich und schematisch erläutert werden. Besonderer Fokus liegt dabei auch auf dem klinischen Bild der jeweiligen Unterformen sowie der therapeutischen Konsequenz, die sich in dieser Krankheitsgruppe direkt aus dem molekulargenetischen Befund ergeben kann. Eine Auswahl weiterer genetischer Syndrome mit arterieller Hypertonie als Begleit- oder Spätsymptom wird zusammenfassend behandelt.

Fazit

Die korrekte Diagnose eines Betroffenen mit einer Form der hier beschriebenen hereditären Hypertonien ermöglicht eine gezielte und effektive medikamentöse Therapie auf Basis der inzwischen insgesamt gut verstandenen jeweiligen Pathomechanismen.

Central intracrine DHEA synthesis in ageing-related neuroinflammation and neurodegeneration: therapeutic potential?

It is a well-known fact that DHEA declines on ageing and that it is linked to ageing-related neurodegeneration, which is characterised by gradual cognitive decline. Although DHEA is also associated with inflammation in the periphery, the link between DHEA and neuroinflammation in this context is less clear. This review drew from different bodies of literature to provide a more comprehensive picture of peripheral vs central endocrine shifts with advanced age—specifically in terms of DHEA. From this, we have formulated the hypothesis that DHEA decline is also linked to neuroinflammation and that increased localised availability of DHEA may have both therapeutic and preventative benefit to limit neurodegeneration. We provide a comprehensive discussion of literature on the potential for extragonadal DHEA synthesis by neuroglial cells and reflect on the feasibility of therapeutic manipulation of localised, central DHEA synthesis.

Recent advances in the study of 11β-Hydroxysteroid dehydrogenase type 2 (11β-HSD2)Inhibitors

11β-Hydroxysteroid dehydrogenase (11β-HSD), which interconverts hormonally active cortisol and inactive cortisone in multiple human tissues, has two distinct isoforms named 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) and 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2). 11β-HSD2 is an NAD⁺-dependent oxidase which lowers cortisol by converting it to cortisone while 11β-HSD1 mainly catalyzes the reduction which converts cortisone into cortisol. Selective inhibition of 11β-HSD2 is generally detrimental to health because the accumulation of cortisol can cause metabolic symptoms such as apparent mineralocorticoid excess (AME), fetal developmental defects and lower testosterone levels in males. There has been some advances on the study of 11β-HSD2 inhibitors and we think it necessary to make a summary of the characteristics and inhibiting properties of latest 11β-HSD2 inhibitors. As another review on 11β-HSD2 inhibitors has been issued on 2011 (see review (Ma et al., 2011)), this mini-review concerns advances during the last 5 years.

JTP-117968, a novel selective glucocorticoid receptor modulator, exhibits improved transrepression/transactivation dissociation

Classic glucocorticoids that have outstanding anti-inflammatory effects are still widely prescribed for the treatment of various inflammatory and autoimmune diseases. Conversely, glucocorticoids cause numerous unwanted side effects, particularly systemically dosed glucocorticoids. Therefore, selective glucocorticoid receptor modulator (SGRM), which maintains beneficial anti-inflammatory effects while reducing the occurrence of side effects, is one of the most anticipated drugs. However, there have been no SGRMs marketed to date. The assumption is that there are two major mechanisms of action of glucocorticoids via glucocorticoid receptors, transrepression (TR) and transactivation (TA). In general, the anti-inflammatory effects of glucocorticoids are mostly mediated through TR, while the side effects associated with glucocorticoids are largely caused by TA. We started to evaluate novel orally available SGRMs that maintain anti-inflammatory effects while minimizing adverse effects by favoring TR over TA. Based on this evaluation, we discovered JTP-117968, (4b'S,7'R,8a'S)-4b'-benzyl-7'-hydroxy-N-(2-methylpyridin-3-yl)-7'-(trifluoromethyl)-4b',6',7',8',8a',10'-hexahydro-5'H-spiro[cyclopropane-1,9'-phenanthrene]-2'-carboxamide, a non-steroidal SGRM. JTP-117968 has partial TR activity, but exhibits extremely low TA activity. The maximum TR efficacy of JTP-117968 was comparable to its structural analogue, PF-802, (4bS,7R,8aR)-4b-Benzyl-7-hydroxy-N-(2-methylpyridin-3-yl)-7-(trifluoromethyl)-4b,5,6,7,8,8a,9,10-octahydrophenanthrene-2-carboxamide, which is the active form of Fosdagrocorat that has been developed clinically as a first-in-class orally available SGRM. Remarkably, the TA activity of JTP-117968 was much weaker than PF-802 not only in in vitro assays, but also in in vivo mice experiments. These findings indicate that JTP-117968 exhibits improved TR/TA dissociation because the compound has significantly lower TA activity compared with an already reported SGRM. Therefore, JTP-117968 is expected to be a useful compound for evaluating ideal SGRMs in the future.

DNA methylation and hypertension: emerging evidence and challenges

Hypertension is a multifactorial disease influenced by an interaction of environmental and genetic factors. The exact molecular mechanism of hypertension remains unknown. Aberrant DNA methylation is the most well-defined epigenetic modification that regulates gene transcription. However, studies on the association between DNA methylation and hypertension are still in their infancy. This review summarizes the latest evidence and challenges regarding the role of DNA methylation on hypertension.

Biased signalling from the glucocorticoid receptor: Renewed opportunity for tailoring glucocorticoid activity

Recent landmark studies applying analytical pharmacology approaches to the glucocorticoid receptor (GR) have demonstrated that different ligands can cause differential activation of distinct GR-regulated genes. Drawing on concepts of signalling bias from the field of G protein-coupled receptor (GPCR) biology, we speculate that ligand-dependent differences in GR signalling can be considered analogous to GPCR biased signalling, and thus can be quantitatively analysed in a similar way. This type of approach opens up the possibility of using rational structure-based drug optimisation strategies to improve the therapeutic selectivity of glucocorticoid drugs to maximise their efficacy and minimise adverse effects.

Discovery of a highly potent glucocorticoid for asthma treatment

Glucocorticoids are the most effective treatment for asthma. However, their clinical applications are limited by low efficacy in severe asthma and by undesired side effects associated with high dose or prolonged use. The most successful approach to overcome these limitations has been the development of highly potent glucocorticoids that can be delivered to the lungs by inhalation to achieve local efficacy with minimal systemic effects. On the basis of our previous structural studies, we designed and developed a highly potent glucocorticoid, VSGC12, which showed an improved anti-inflammation activity in both cell-based reporter assays and cytokine inhibition experiments, as well as in a gene expression profiling of mouse macrophage RAW264.7 cells. In a mouse asthma model, VSGC12 delivered a higher efficacy than fluticasone furoate, a leading clinical compound, in many categories including histology and the number of differentiated immune cells. VSGC12 also showed a higher potency than fluticasone furoate in repressing most asthma symptoms. Finally, VSGC12 showed a better side effect profile than fluticasone furoate at their respective effective doses, including better insulin response and less bone loss in an animal model. The excellent therapeutic and side effect properties of VSGC12 provide a promising perspective for developing this potent glucocorticoid as a new effective drug for asthma.

Sustained-release steroids for the treatment of diabetic macular edema

Glucocorticoids have been used for decades in the treatment of ocular disorders via topical, periocular, and more recently intravitreal routes. However, their exact mechanisms of action on ocular tissues remain imperfectly understood. Fortunately, two recently approved intravitreal sustained-release drug delivery systems have opened new perspectives for these very potent drugs. To date, among other retinal conditions, their label includes diabetic macular edema, for which a long-lasting therapeutic effect has been demonstrated both morphologically and functionally in several randomized clinical trials. The rate of ocular complications of intravitreal sustained-release steroids, mainly cataract formation and intraocular pressure elevation, is higher than with anti-vascular endothelial growth factor agents. Yet, a better understanding of the mechanisms underlying these adverse effects and the search for the minimal efficient dose should help optimize their therapeutic window.

Glucocorticoid receptor function in health and disease

Glucocorticoid hormones are essential for life in vertebrates. They act through the glucocorticoid receptor (GR), which is expressed in virtually all cells of the human body. Yet the actions of glucocorticoids (GCs) are specific to particular cell types. Broadly GCs regulate carbohydrate metabolism, inflammation, stress and cell fate. Synthetic GCs are widely used in medicine and are by far the most frequent cause of Cushing's syndrome in routine practice. The advent of novel drugs targeting the GR offers new opportunities to treat patients with immune, or malignant disease, and may also offer new opportunities to manage patients with adrenal insufficiency also. This review covers the latest understanding of how GCs work, how their actions are affected by disease, and where the new drugs may take us.

Hypercortisolism in obesity-associated hypertension

Obesity is prevalent worldwide and associated with co-morbidities that result in increased cardiovascular risk. Hypertension is the most prevalent obesity comorbidity associated with increased cardiovascular risk. Obesity hypertension is a distinct subtype of essential hypertension. While endogenous Cushing's syndrome is an uncommon cause of both obesity and hypertension, the recent recognition of other hypercortisolemic states has raised the profile of hypercortisolism as an important contributor in obesity hypertension. The high prevalence of exogenous, iatrogenic, pseudo, and subclinical Cushing's syndromes makes hypercortisolism an important diagnostic consideration in the evaluation and management of patients with obesity hypertension who are resistant to conventional management. Available data suggest that the renin-angiotensin-aldosterone system modulating antihypertensives have the best efficacy in hypercortisolism-mediated obesity hypertension. Strategies aimed at reducing cortisol production and action also have utility. This review provides a comprehensive overview of the epidemiology, etiopathogenesis and management options available for glucocorticoid-mediated obesity hypertension.

The effects of canrenone on inflammatory markers in patients with metabolic syndrome

AIM

To evaluate the effects of canrenone compared to placebo on blood pressure control, some non-conventional biomarkers in cardiovascular stratification, and on metalloproteinases in patients affected by metabolic syndrome.

METHODS

A total of 156 Caucasian patients were treated with placebo or canrenone, 50 mg once a day, for 3 months and then 50 mg twice a day, till the end of the study. We evaluated: systolic (SBP) and diastolic blood pressure (DBP), body weight, body mass index (BMI), fasting plasma glucose (FPG), lipid profile, plasma aldosterone, creatinine, potassium, brain natriuretic peptide (BNP), metalloproteinases 2 and 9 (MMP-2 and -9), lipoprotein (a) (Lp(a)), and serum myeloperoxidase (MPO).

RESULTS

We observed a significant decrease of SBP and DBP in the canrenone group compared to baseline. Canrenone gave a significant decrease of MMP-2 and -9, Lp(a), and MPO compared to baseline, not observed with placebo. Plasma aldosterone, but not BNP, decreased with canrenone, both compared to baseline and to placebo.

CONCLUSION

Canrenone seems to be effective in reducing blood pressure in patients with metabolic syndrome. Moreover, canrenone seems also to improve MPO, Lp(a), and metalloproteinases in these patients.

Hypertensive epigenetics: from DNA methylation to microRNAs

The major epigenetic features of mammalian cells include DNA methylation, posttranslational histone modifications and RNA-based mechanisms including those controlled by small non-coding RNAs (microRNAs (miRNAs)). An important aspect of epigenetic mechanisms is that they are potentially reversible and may be influenced by nutritional-environmental factors and through gene-environment interactions. Studies on epigenetic modulations could help us understand the mechanisms involved in essential hypertension and further prevent it's progress. This review is focused on new knowledge on the role of epigenetics, from DNA methylation to miRNAs, in essential hypertension.

Safety Profile and Effects of Pulsed Methylprednisolone on Vital Signs in Thyroid Eye Disease

Objective. To analyze changes in vital signs (heart rate (HR), systolic (SBP), and diastolic blood pressure (DBP)) during and after intravenous methylprednisolone (IVMP) and any other adverse effects. Methods. Retrospective review of charts of patients who received IVMP as treatment regime for thyroid eye disease. All subjects had vital signs charted during and after infusions. Results. This study included 38 subjects and a total of 242 infusions administered. IVMP resulted in a small but significant percentage drop in mean SBP at 30 min (p < 0.001) and 60 min (p = 0.03) but no difference at 90 min. There was also small but significant percentage drop in mean DBP and HR (DBP: p < 0.001 for 30 min, p = 0.001 for 60 min, and p = 0.02 for 90 min and HR: p < 0.001 for 30 min, 60 min, and 90 min). There were no cumulative effects on change of blood pressure or HR. There were 6 episodes of bradycardia (2.5%) and 12 episodes of moderate to severe hypertension (5%). No significant cardiovascular or hepatic toxicity was found. Conclusion. IVMP is relatively safe and efficacious. IVMP demonstrated mild and noncumulative effects on vital signs. Severe hypertension may occur in susceptible individuals such as those with underlying hypertension and uncontrolled thyroid dysfunction, whereas bradycardia may be more likely in those on beta-blockers.

Circadian characteristics of permissive and suppressive effects of cortisol and their role in homeostasis and the acute inflammatory response

In this work we explore a semi-mechanistic model that considers cortisol's permissive and suppressive effects through the regulation of cytokine receptors and cytokines respectively. Our model reveals the proactive role of cortisol during the resting period and its reactive character during the body's activity phase. Administration of an acute LPS dose during the night, when cortisol's permissive effects are higher than suppressive, leads to increased cytokine levels compared to LPS administration at morning when cortisol's suppressive effects are higher. Interestingly, our model presents a hysteretic behavior where the relative predominance of permissive or suppressive effects results not only from cortisol levels but also from the previous states of the model. Therefore, for the same cortisol levels, administration of an inflammatory stimulus at cortisol's ascending phase, that follows a time period where cytokine receptor expression is elevated ultimately sensitizing the body for the impending stimulus, leads to higher cytokine expression compared to administration of the same stimulus at cortisol's descending phase.

Daily liquorice consumption for two weeks increases augmentation index and central systolic and diastolic blood pressure

BACKGROUND

Liquorice ingestion often elevates blood pressure, but the detailed haemodynamic alterations are unknown. We studied haemodynamic changes induced by liquorice consumption in 20 subjects versus 30 controls with average blood pressures of 120/68 and 116/64 mmHg, respectively.

METHODS

Haemodynamic variables were measured in supine position before and after two weeks of liquorice consumption (daily glycyrrhizin dose 290-370 mg) with tonometric recording of radial blood pressure, pulse wave analysis, and whole-body impedance cardiography. Thirty age-matched healthy subjects maintaining their normal diet were studied as controls.

RESULTS

Two weeks of liquorice ingestion elevated peripheral and central systolic and diastolic blood pressure (by 7/4 and 8/4 mmHg, 95% confidence intervals [CI] 2-11/1-8 and 3-13/1-8, respectively, P<0.05), and increased extracellular volume by 0.5 litres (P<0.05 versus controls). Also augmentation index adjusted to heart rate 75/min (from 7% to 11%, 95% CI for change 0.3-7.5, P<0.05) and aortic pulse pressure (by 4 mmHg, 95% CI 1-7, P<0.05) were elevated indicating increased wave reflection from the periphery. In contrast, peripheral (-3/-0.3 mmHg) and central blood pressure (-2/-0.5 mmHg), aortic pulse pressure (-1 mmHg), and augmentation index adjusted to heart rate 75/min (from 9% to 7%) decreased numerically but not statistically significantly without changes in extracellular volume in the control group. Heart rate, systemic vascular resistance, cardiac output, and pulse wave velocity did not differ between the groups.

CONCLUSIONS

Two weeks of daily liquorice consumption increased extracellular volume, amplified pressure wave reflection from the periphery, and elevated central systolic and diastolic blood pressure.

TRIAL REGISTRATION

EU Clinical Trials Register EudraCT 2006-002065-39 ClinicalTrials.gov NCT01742702.

Bisphenol A increases aP2 expression in 3T3L1 by enhancing the transcriptional activity of nuclear receptors at the promoter

Environmental pollutants, such as bisphenol A (BPA), have the potential to affect the differentiation processes and the biology of the adipose tissue. The 3T3-L1 model is one of the murine cell models used extensively for the investigation of the molecular events that govern the differentiation of adipocytes from a committed preadipocyte to a mature, lipid laden adipocyte. Most of the studies investigating the effects of BPA on preadipocyte differentiation have investigated the effects of this chemical in the presence of an optimal differentiation cocktail containing high concentrations of the synthetic glucocorticoid dexamethasone, conditions that result in 90% to 100% of differentiated adipocytes. Our studies employed the 3T3-L1 cell model in the absence of exogenous glucocorticoids. We show that BPA is able to increase the differentiation of the 3T3-L1 cells under these conditions. Furthermore, the effect of BPA was observed in the absence of the synthetic glucocorticoid (dexamethasone), a hormone known to be required for the differentiation of the 3T3-L1 cells. In addition, BPA upregulated the mRNA expression and protein levels of the terminal marker of adipogenesis the fatty acid binding protein (aP2) in these cells. Interestingly, the known modulators of adipogenesis such as the peroxisome proliferator-activated receptor (PPAR) γ or CCAAT enhancer binding protein (C/EBP) α were not elevated at the mRNA or protein level in response to BPA. Furthermore, BPA upregulated the expression levels of the marker of adipogenesis aP2, through an effect on the transcriptional activity of C/EBPδ and the glucocorticoid receptor (GR) at its promoter.

The multifaceted mineralocorticoid receptor

The primary adrenal cortical steroid hormones, aldosterone, and the glucocorticoids cortisol and corticosterone, act through the structurally similar mineralocorticoid (MR) and glucocorticoid receptors (GRs). Aldosterone is crucial for fluid, electrolyte, and hemodynamic homeostasis and tissue repair; the significantly more abundant glucocorticoids are indispensable for energy homeostasis, appropriate responses to stress, and limiting inflammation. Steroid receptors initiate gene transcription for proteins that effect their actions as well as rapid non-genomic effects through classical cell signaling pathways. GR and MR are expressed in many tissues types, often in the same cells, where they interact at molecular and functional levels, at times in synergy, others in opposition. Thus the appropriate balance of MR and GR activation is crucial for homeostasis. MR has the same binding affinity for aldosterone, cortisol, and corticosterone. Glucocorticoids activate MR in most tissues at basal levels and GR at stress levels. Inactivation of cortisol and corticosterone by 11β-HSD2 allows aldosterone to activate MR within aldosterone target cells and limits activation of the GR. Under most conditions, 11β-HSD1 acts as a reductase and activates cortisol/corticosterone, amplifying circulating levels. 11β-HSD1 and MR antagonists mitigate inappropriate activation of MR under conditions of oxidative stress that contributes to the pathophysiology of the cardiometabolic syndrome; however, MR antagonists decrease normal MR/GR functional interactions, a particular concern for neurons mediating cognition, memory, and affect.

A pilot study of the effects of eplerenone add-on therapy in patients taking renin-angiotensin system blockers

HYPOTHESIS

This study determined the parameters for predicting the clinical effects of eplerenone (Ep) add-on therapy on blood pressure (BP) and proteinuria in patients taking angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II type I receptor blockers (ARBs).

MATERIALS AND METHODS

Patients were treated with a gradual increase of Ep to a final dose of 50 mg/day for 2 months. In 35 patients, the efficacy of Ep was evaluated by peripheral BP, proteinuria, and the transtubular K gradient (TTKG). Fifteen patients had additional analysis for central BP, plasma renin activity (PRA) and plasma aldosterone concentration (PAC), measured in the supine position, and 24-hour urine collection before and after receiving Ep.

RESULTS

Ep add-on therapy reduced the mean arterial pressure (p=0.0005) and central BP (p=0.009) independently to the baseline PAC. Ep induced PRA, but failed to show effects on PAC, TTKG, or albuminuria. Correlation analysis showed inverse relationships between the percent reduction in albuminuria and baseline PAC.

CONCLUSIONS

Ep add-on therapy in patients taking renin-angiotensin system blockers is expected to reduce BP, even in patients with low PAC. In contrast, the anti-proteinuric action of Ep is dependent on baseline plasma aldosterone levels. TTKG is not appropriate for evaluating the efficacy of Ep.

Structures and mechanism for the design of highly potent glucocorticoids

The evolution of glucocorticoid drugs was driven by the demand of lowering the unwanted side effects, while keeping the beneficial anti-inflammatory effects. Potency is an important aspect of this evolution as many undesirable side effects are associated with use of high-dose glucocorticoids. The side effects can be minimized by highly potent glucocorticoids that achieve the same treatment effects at lower doses. This demand propelled the continuous development of synthetic glucocorticoids with increased potencies, but the structural basis of their potencies is poorly understood. To determine the mechanisms underlying potency, we solved the X-ray structures of the glucocorticoid receptor (GR) ligand-binding domain (LBD) bound to its endogenous ligand, cortisol, which has relatively low potency, and a highly potent synthetic glucocorticoid, mometasone furoate (MF). The cortisol-bound GR LBD revealed that the flexibility of the C1-C2 single bond in the steroid A ring is primarily responsible for the low affinity of cortisol to GR. In contrast, we demonstrate that the very high potency of MF is achieved by its C-17α furoate group completely filling the ligand-binding pocket, thus providing additional anchor contacts for high-affinity binding. A single amino acid in the ligand-binding pocket, Q642, plays a discriminating role in ligand potency between MF and cortisol. Structure-based design led to synthesis of several novel glucocorticoids with much improved potency and efficacy. Together, these results reveal key structural mechanisms of glucocorticoid potency and provide a rational basis for developing novel highly potent glucocorticoids.

Leveraging melanocortin pathways to treat glomerular diseases

The melanocortin system is a neuroimmunoendocrine hormone system that constitutes the fulcrum in the homeostatic control of a diverse array of physiological functions, including melanogenesis, inflammation, immunomodulation, adrenocortical steroidogenesis, hemodynamics, natriuresis, energy homeostasis, sexual function, and exocrine secretion. The kidney is a quintessential effector organ of the melanocortin hormone system with melanocortin receptors abundantly expressed by multiple kidney parenchymal cells, including podocytes, mesangial cells, glomerular endothelial cells, and renal tubular cells. Converging evidence unequivocally demonstrates that the melanocortin-based therapy using the melanocortin peptide adrenocorticotropic hormone (ACTH) is prominently effective in inducing remission of steroid-resistant nephrotic syndrome caused by various glomerular diseases, including membranous nephropathy, minimal change disease and focal segmental glomerulosclerosis, suggesting a steroidogenic-independent mechanism. Mechanistically, ACTH and other synthetic melanocortin analogues possess potent proteinuria-reducing and renoprotective activities that could be attributable to direct protection of glomerular cells and systemic immunomodulation. Thus, leveraging melanocortin signaling pathways using ACTH or novel synthetic melanocortin analogues represents a promising and pragmatic therapeutic strategy for glomerular diseases. This review article introduces the biophysiology of the melanocortin hormone system with an emphasis on the kidney as a target organ, discusses the existing data on melanocortin therapy for glomerular diseases, and elucidates the potential mechanisms of action.

Evidence for glucocorticoid-mediated hypertension after uninephrectomy

Recently, evidence was presented that uninephrectomy induces salt-sensitive hypertension in rats. The increase in blood pressure was abrogated by a mineralocorticoid receptor antagonist but not by an aldosterone synthase inhibitor. Here, we hypothesize that mineralocorticoid receptor activation occurred by an 11beta-hydroxy-glucocorticosteroid, as a consequence of dysregulated 11beta-hydroxysteroid dehydrogenase enzymes. Therefore, 3-week-old Sprague-Dawley rats were either uninephrectomized or sham operated and given a normal (0.4%) or high (8%)-salt diet. At week 8, a telemetric device was implanted, and during week 13 blood pressure continuously measured and urine was collected. The animals were sacrificed thereafter and liver and kidney were harvested. Steroid metabolites were analyzed by GC-MS and mRNA assessed by PCR. Uninephrectomy caused a distinct salt-sensitive hypertension. The increase in blood pressure correlated significantly with a decline in the apparent activity of 11beta-hydroxysteroid dehydrogenase 2 and an increase of 11beta-hydroxysteroid dehydrogenase 1, when urinary corticosterone metabolites were considered. These results were mirrored by the corresponding metabolite ratios assessed in renal and liver tissue. Changes in enzyme activities were in part explained by changes in the mRNA content. In conclusion, mineralocorticoid receptor-dependent salt sensitivity after UNX in rats appears to be mediated by glucocorticoids.