Increased in vivo regeneration of cortisol in adipose tissue in human obesity and effects of the 11beta-hydroxysteroid dehydrogenase type 1 inhibitor carbenoxolone

Corticosteroid rhythms in hypoparathyroid patients

OBJECTIVE

Previous studies indicate a possible bidirectional stimulatory relationship between parathyroid hormone (PTH) and adrenocortical hormones, but the pattern of adrenocortical secretion in hypoparathyroidism is unknown. We aimed to characterize the adrenocortical secretion in patients with postsurgical hypoparathyroidism, and whether continuous subcutaneous PTH (1-34) infusion alters secretion patterns.

DESIGN

Crossover interventional study.

METHODS

We recruited 10 patients with postsurgical hypoparathyroidism with very low PTH levels on stable treatment with active vitamin D and calcium. Cortisol, cortisone, and aldosterone levels were measured in microdialysate from subcutaneous tissue over 24 h, before and during continuous subcutaneous PTH (1-34) infusion. Cortisol was also assayed in serum, saliva, and urine, and aldosterone and ACTH in serum and plasma, respectively. Ten patients with primary hyperparathyroidism and 10 healthy volunteers matched for sex and age served as controls.

RESULTS

Hypoparathyroid patients displayed both ultradian and circadian rhythmicity for tissue cortisol, cortisone, and aldosterone. Tissue aldosterone and cortisone levels were significantly lower in hypoparathyroid patients than in healthy controls, with no difference in tissue cortisol, but a higher cortisol to cortisone ratio. Treatment with PTH (1-34) increased tissue levels of aldosterone, cortisol, and cortisone and reduced the ratio of cortisol to cortisone.

CONCLUSION

Adrenocortical hormone levels are reduced in postsurgical hypoparathyroidism, and partly restored by short-term continuous subcutaneous PTH (1-34) therapy.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02986607.

Risk factors and disease associations in people living with idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension is a neurological condition characterized by a raised intracranial pressure and papilledema, leading to chronic headaches and visual disturbances. By recognizing modifiable risk factors and deploying evidence-based interventions, healthcare providers have the potential to mitigate the burden of the disease and improve patient outcomes.

AREAS COVERED

It is well known that the condition occurs in predominantly pre-menopausal females who live with obesity particularly in the context of recent weight gain. This review discusses what risk factors may contribute to the metabolic underpinnings of cerebrospinal fluid dysregulation. There are a number of disease associations that are important to screen for as they can alter management.

EXPERT OPINION

There is emerging evidence to suggest that idiopathic intracranial hypertension is a systemic metabolic disease and it is unknown what are all the risk factors are that precipitate the condition. Targeting certain hardwired risk factors is unachievable. However, as recent weight gain has been identified as a predominant risk factor for the development of the disease and relapse, modification of body weight should be the primary aim of management. Insightful research into the involvement of the neuroendocrine axis driving cerebrospinal fluid dysregulation now has the potential for the development of therapeutic targets.

Association of seasonal changes in circulating cortisol concentrations with the expression of cortisol biosynthetic enzymes and a glucocorticoid receptor in the blubber of common bottlenose dolphin

Cortisol is secreted from the adrenal cortex in response to stress, and its circulating levels are used as robust physiological indicators of stress intensity in various animals. Cortisol is also produced locally in adipose tissue by the conversion of steroid hormones such as cortisone, which is related to fat accumulation. Circulating cortisol levels, probably induced by cold stress, increase in cetaceans under cold conditions. However, whether cortisol production in subcutaneous adipose tissue is enhanced when fat accumulation is renewed during the cold season remains unclear. Therefore, in this study, we examine the effect of environmental temperature on the expression of cortisol synthesis-related enzymes and a glucocorticoid receptor in the subcutaneous fat (blubber) and explore the association between these expressions and fluctuations in circulating cortisol levels in common bottlenose dolphins (Tursiops truncatus). Skin biopsies were obtained seasonally from eight female dolphins, and seasonal differences in the expression of target genes in the blubber were analyzed. Blood samples were collected throughout the year, and cortisol levels were measured. We found that the expressions of cytochrome P450 family 21 subfamily A member 2 (CYP21A2) and nuclear receptor subfamily 3 group C member 1 (NR3C1), a glucocorticoid receptor, were increased in the cold season, and 11 beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) showed a similar trend. Blood cortisol levels increased when the water temperature decreased. These results suggest that the conversion of 17-hydroxyprogesterone to cortisol via 11-deoxycortisol and/or of cortisone to cortisol is enhanced under cold conditions, and the physiological effects of cortisol in subcutaneous adipose tissue may contribute to on-site lipid accumulation and increase the circulating cortisol concentrations. The results obtained in this study highlight the role of cortisol in the regulation of the blubber that has developed to adapt to aquatic life.

Advancements in Cortisol Detection: From Conventional Methods to Next-Generation Technologies for Enhanced Hormone Monitoring

The hormone cortisol, released as the end-product of the hypothalamic-pituitary-adrenal (HPA) axis, has a well-characterized circadian rhythm that enables an allostatic response to external stressors. When the pattern of secretion is disrupted, cortisol levels are chronically elevated, contributing to diseases such as heart attacks, strokes, mental health disorders, and diabetes. The diagnosis of chronic stress and stress related disorders depends upon accurate measurement of cortisol levels; currently, it is quantified using mass spectroscopy or immunoassay, in specialized laboratories with trained personnel. However, these methods are time-consuming, expensive and are unable to capture the dynamic biorhythm of the hormone. This critical review traces the path of cortisol detection from traditional laboratory-based methods to decentralised cortisol monitoring biosensors. A complete picture of cortisol biology and pathophysiology is provided, and the importance of precision medicine style monitoring of cortisol is highlighted. Antibody-based immunoassays still dominate the pipeline of development of point-of-care biosensors; new capture molecules such as aptamers and molecularly imprinted polymers (MIPs) combined with technologies such as microfluidics, wearable electronics, and quantum dots offer improvements to limit of detection (LoD), specificity, and a shift toward rapid or continuous measurements. While a variety of different sensors and devices have been proposed, there still exists a need to produce quantitative tests for cortisol ─ using either rapid or continuous monitoring devices that can enable a personalized medicine approach to stress management. This can be addressed by synergistic combinations of technologies that can leverage low sample volumes, relevant limit of detection and rapid testing time, to better account for cortisol's shifting biorhythm. Trends in cortisol diagnostics toward rapid and continuous monitoring of hormones are highlighted, along with insights into choice of sample matrix.

Inhibition of the glucocorticoid-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 drives concurrent 11-oxygenated androgen excess

Aldo-keto reductase 1C3 (AKR1C3) is a key enzyme in the activation of both classic and 11-oxygenated androgens. In adipose tissue, AKR1C3 is co-expressed with 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1), which catalyzes not only the local activation of glucocorticoids but also the inactivation of 11-oxygenated androgens, and thus has the potential to counteract AKR1C3. Using a combination of in vitro assays and in silico modeling we show that HSD11B1 attenuates the biosynthesis of the potent 11-oxygenated androgen, 11-ketotestosterone (11KT), by AKR1C3. Employing ex vivo incubations of human female adipose tissue samples we show that inhibition of HSD11B1 results in the increased peripheral biosynthesis of 11KT. Moreover, circulating 11KT increased 2-3 fold in individuals with type 2 diabetes after receiving the selective oral HSD11B1 inhibitor AZD4017 for 35 days, thus confirming that HSD11B1 inhibition results in systemic increases in 11KT concentrations. Our findings show that HSD11B1 protects against excess 11KT production by adipose tissue, a finding of particular significance when considering the evidence for adverse metabolic effects of androgens in women. Therefore, when targeting glucocorticoid activation by HSD11B1 inhibitor treatment in women, the consequently increased generation of 11KT may offset beneficial effects of decreased glucocorticoid activation.

Tissue Glucocorticoid Metabolism in Adrenal Insufficiency: A Prospective Study of Dual-release Hydrocortisone Therapy

BACKGROUND

Patients with adrenal insufficiency (AI) require life-long glucocorticoid (GC) replacement therapy. Within tissues, cortisol (F) availability is under the control of the isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD). We hypothesize that corticosteroid metabolism is altered in patients with AI because of the nonphysiological pattern of current immediate release hydrocortisone (IR-HC) replacement therapy. The use of a once-daily dual-release hydrocortisone (DR-HC) preparation, (Plenadren®), offers a more physiological cortisol profile and may alter corticosteroid metabolism in vivo.

STUDY DESIGN AND METHODS

Prospective crossover study assessing the impact of 12 weeks of DR-HC on systemic GC metabolism (urinary steroid metabolome profiling), cortisol activation in the liver (cortisone acetate challenge test), and subcutaneous adipose tissue (microdialysis, biopsy for gene expression analysis) in 51 patients with AI (primary and secondary) in comparison to IR-HC treatment and age- and BMI-matched controls.

RESULTS

Patients with AI receiving IR-HC had a higher median 24-hour urinary excretion of cortisol compared with healthy controls (72.1 µg/24 hours [IQR 43.6-124.2] vs 51.9 µg/24 hours [35.5-72.3], P = .02), with lower global activity of 11β-HSD2 and higher 5-alpha reductase activity. Following the switch from IR-HC to DR-HC therapy, there was a significant reduction in urinary cortisol and total GC metabolite excretion, which was most significant in the evening. There was an increase in 11β-HSD2 activity. Hepatic 11β-HSD1 activity was not significantly altered after switching to DR-HC, but there was a significant reduction in the expression and activity of 11β-HSD1 in subcutaneous adipose tissue.

CONCLUSION

Using comprehensive in vivo techniques, we have demonstrated abnormalities in corticosteroid metabolism in patients with primary and secondary AI receiving IR-HC. This dysregulation of pre-receptor glucocorticoid metabolism results in enhanced glucocorticoid activation in adipose tissue, which was ameliorated by treatment with DR-HC.

Experimental drugs for the treatment of idiopathic intracranial hypertension (IIH): shedding light on phase I and II trials

INTRODUCTION

Idiopathic intracranial hypertension is a neurological condition characterized by a raised intracranial pressure and papilledema that causes debilitating headaches. While the extent of the pathophysiology is being discovered, the condition is emerging as a systemic metabolic disease distinct to people living with obesity alone. Idiopathic intracranial hypertension is becoming more common and therefore establishing licensed therapeutics is a key priority.

AREA COVERED

The translation of preclinical work in idiopathic intracranial hypertension is evident by the two early phase trials evaluating 11-β-hydroxysteroid dehydrogenase inhibitor, AZD4017, and a glucagon like peptide-1 receptor agonist, Exenatide. This review summarizes these two early phase trials evaluating targeted medicines for the treatment of intracranial pressure. The modulation of these two distinct mechanisms have potential for therapeutic intervention in people living with idiopathic intracranial hypertension.

EXPERT OPINION

The clinical trial landscape in idiopathic intracranial hypertension is a challenge due to the rarity of the disease and the lack of agreed meaningful trial outcomes. Further preclinical work to fully understand the pathogenesis is required to enable personalized targeted drug treatment.

Stress, Stress Reduction and Obesity in Childhood and Adolescence

BACKGROUND

Obesity in childhood and adolescence remains a great global health challenge. Stress exposure during childhood and adolescence is associated with a higher risk for obesity, yet the linkage between stress and obesity is multidimensional, and its biological and behavioral mechanisms are still not fully understood.

SUMMARY

In this literature review, we identified different types of stress exposure in children and adolescents, including first studied effects of the COVID-19 pandemic as a prolonged stress exposure and their association with obesity risk. We investigated studies on the connection of altered stress biology and behavioral pathways as well as intervention programs on stress reduction in children and adolescents with obesity.

KEY MESSAGES

There is evidence that stress exposure in childhood and adolescence promotes biological and behavioral alterations that contribute to the multifactorial pathogenesis of obesity. COVID-19 related-stress presents the most current example of a negative influence on weight development in children and adolescents. However, longitudinal studies on the linkage between environmental, behavioral, and biological factors across development are few, and results are partly equivocal. Intervention programs to reduce stress in children through mindfulness might be a promising adjunctive tool in the prevention and treatment of childhood and adolescent obesity that could further offer proof of concept of theoretically elaborated cause-and-effect relationships.

Safety, tolerability, pharmacodynamics and pharmacokinetics following once-daily doses of BI 187004, an inhibitor of 11 beta-hydroxysteroid dehydrogenase-1, over 28 days in patients with type 2 diabetes mellitus and overweight or obesity

AIMS

To study the oral 11 beta-hydroxysteroid dehydrogenase-1 (11β-HSD1) inhibitor BI 187004 (NCT02150824), as monotherapy and in combination with metformin, versus placebo in patients with type 2 diabetes mellitus (T2DM) affected by overweight or obesity.

MATERIALS AND METHODS

This Phase II, randomized controlled trial investigated multiple rising doses of BI 187004 as monotherapy (Arm 1: 20, 80 or 240 mg) and in combination with metformin (Arm 2: 240 mg), in adults with T2DM and a body mass index of 28-40 kg/m² .

RESULTS

In total, 103 patients (Arm 1: n = 62, Arm 2: n = 41) were included in this study. BI 187004 was rapidly absorbed and exposure increased approximately dose-dependently. Target engagement of 11β-HSD1 was observed with near-full inhibition of 11β-HSD1 in the liver [decreased (5α-tetrahydrocortisol + 5β-tetrahydrocortisol)/tetrahydrocortisone ratio]; hypothalamic-pituitary-adrenal axis activation was also seen (increased total urinary corticosteroids). No clinically relevant changes from baseline with BI 187004 treatment were observed for bodyweight or meal tolerance test parameters, or in most efficacy endpoints testing glucose and lipid metabolism; a significant increase was observed in weighted mean plasma glucose (p < .05 for 80 and 240 mg BI 187004) but not fasting plasma glucose. Drug-related adverse events were reported for 14 patients (22.6%) in Arm 1 and 10 patients (24.4%) in Arm 2, most frequently headache, diarrhoea, flushing and dizziness. A dose-dependent increase in heart rate was seen with BI 187004 treatment.

CONCLUSIONS

BI 187004 was generally well tolerated in patients with T2DM. Despite complete 11β-HSD1 inhibition, no clinically relevant effects were observed with BI 187004.

11β-Hydroxysteroid Dehydrogenase Type 1 as a Potential Treatment Target in Cardiovascular Diseases

Glucocorticoids (GCs) belong to the group of steroid hormones. Their representative in humans is cortisol. GCs are involved in most physiological processes of the body and play a significant role in important biological processes, including reproduction, growth, immune responses, metabolism, maintenance of water and electrolyte balance, functioning of the central nervous system and the cardiovascular system. The availability of cortisol to the glucocorticoid receptor is locally controlled by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Evidence of changes in intracellular GC metabolism in the pathogenesis of obesity, metabolic syndrome (MetS) and cardiovascular complications highlights the role of selective 11β-HSD1 inhibition in the pharmacotherapy of these diseases. This paper discusses the role of 11β-HSD1 in MetS and its cardiovascular complications and the importance of selective inhibition of 11β-HSD1.

Non-invasive in vivo assessment of 11β-hydroxysteroid dehydrogenase type 1 activity by 19F-Magnetic Resonance Spectroscopy

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) amplifies tissue glucocorticoid levels and is a pharmaceutical target in diabetes and cognitive decline. Clinical translation of inhibitors is hampered by lack of in vivo pharmacodynamic biomarkers. Our goal was to monitor substrates and products of 11β-HSD1 non-invasively in liver via ¹⁹Fluorine magnetic resonance spectroscopy (¹⁹F-MRS). Interconversion of mono/poly-fluorinated substrate/product pairs was studied in Wistar rats (male, n = 6) and healthy men (n = 3) using 7T and 3T MRI scanners, respectively. Here we show that the in vitro limit of detection, as absolute fluorine content, was 0.625 μmole in blood. Mono-fluorinated steroids, dexamethasone and 11-dehydrodexamethasone, were detected in phantoms but not in vivo in human liver following oral dosing. A non-steroidal polyfluorinated tracer, 2-(phenylsulfonyl)-1-(4-(trifluoromethyl)phenyl)ethanone and its metabolic product were detected in vivo in rat liver after oral administration of the keto-substrate, reading out reductase activity. Administration of a selective 11β-HSD1 inhibitor in vivo in rats altered total liver ¹⁹F-MRS signal. We conclude that there is insufficient sensitivity to measure mono-fluorinated tracers in vivo in man with current dosage regimens and clinical scanners. However, since reductase activity was observed in rats using poly-fluorinated tracers, this concept could be pursued for translation to man with further development.

11β-HSD as a New Target in Pharmacotherapy of Metabolic Diseases

Glucocorticoids (GCs), which are secreted by the adrenal cortex, are important regulators in the metabolism of carbohydrates, lipids, and proteins. For the proper functioning of the body, strict control of their release is necessary, as increased GCs levels may contribute to the development of obesity, type 2 diabetes mellitus, hypertension, cardiovascular diseases, and other pathological conditions contributing to the development of metabolic syndrome. 11β-hydroxysteroid dehydrogenase type I (11β-HSD1) locally controls the availability of the active glucocorticoid, namely cortisol and corticosterone, for the glucocorticoid receptor. Therefore, the participation of 11β-HSD1 in the development of metabolic diseases makes both this enzyme and its inhibitors attractive targets in the pharmacotherapy of the above-mentioned diseases.

Discovery of 1'-(1-phenylcyclopropane-carbonyl)-3H-spiro[isobenzofuran-1,3'-pyrrolidin]-3-one as a novel steroid mimetic scaffold for the potent and tissue-specific inhibition of 11β-HSD1 using a scaffold-hopping approach

11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) has been identified as the primary enzyme responsible for the activation of hepatic cortisone to cortisol in specific peripheral tissues resulting in the concomitant antagonism of insulin action within these tissues. Dysregulation of 11β-HSD1, particularly in adipose tissues, has been associated with metabolic syndrome and type 2 diabetes mellitus. Therefore, inhibition of 11β-HSD1 with a small nonsteroidal molecule is therapeutically desirable. Implementation of a scaffold-hopping approach revealed a three-point pharmacophore for 11β-HSD1 that was utilized to design a steroid mimetic scaffold. Reiterative optimization provided valuable insight into the bioactive conformation of our novel scaffold and led to the discovery of INCB13739. Clinical evaluation of INCB13739 confirmed for the first time that tissue-specific inhibition of 11β-HSD1 in patients with type 2 diabetes mellitus was efficacious in controlling glucose levels and reducing cardiovascular risk factors.

Effects of Obesity and Insulin on Tissue-Specific Recycling Between Cortisol and Cortisone in Men

CONTEXT

11β-Hydroxysteroid dehydrogenase 1 (11βHSD1) reduces inert cortisone into active cortisol but also catalyzes reverse dehydrogenase activity. Drivers of cortisol/cortisone equilibrium are unclear. With obesity, 11βHSD1 transcripts are more abundant in adipose, but the consequences for oxidation vs reduction remain unknown.

OBJECTIVE

This work aimed to determine whether 11βHSD1 equilibrium in metabolic tissues is regulated by insulin and obesity.

METHODS

A 2-phase, randomized, crossover, single-blinded study in a clinical research facility was conducted of 10 lean and obese healthy men. 11β-Reductase and 11β-dehydrogenase activities were measured during infusion of 9,11,12,12-[2H]4-cortisol and 1,2-[2H]2-cortisone, respectively, on 2 occasions: once during saline infusion and once during a hyperinsulinemic-euglycemic clamp. Arterialized and venous samples were obtained across forearm skeletal muscle and abdominal subcutaneous adipose. Steroids were quantified by liquid chromatography-tandem mass spectrometry and adipose tissue transcripts by quantitative polymerase chain reaction.

RESULTS

Neither whole-body nor tissue-specific rates of production of cortisol or cortisone differed between lean and obese men, however insulin attenuated the diurnal decrease. Whole-body 11β-HSD1 reductase activity tended to be higher in obesity (~ 10%) and was further increased by insulin. Across adipose tissue, 11β-reductase activity was detected in obese individuals only and increased in the presence of insulin (18.99 ± 9.62 vs placebo 11.68 ± 3.63 pmol/100 g/minute; P < .05). Across skeletal muscle, 11β-dehydrogenase activity was reduced by insulin in lean men only (2.55 ± 0.90 vs 4.50 ± 1.42 pmol/100 g/minute, P < .05).

CONCLUSIONS

Regeneration of cortisol is upregulated by insulin in adipose tissue but not skeletal muscle. In obesity, the equilibrium between 11β-reductase and 11β-dehydrogenase activities likely promotes cortisol accumulation in adipose, which may lead to adverse metabolic consequences.

11βHSD1 Inhibition with AZD4017 Improves Lipid Profiles and Lean Muscle Mass in Idiopathic Intracranial Hypertension

BACKGROUND

The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) determines prereceptor metabolism and activation of glucocorticoids within peripheral tissues. Its dysregulation has been implicated in a wide array of metabolic diseases, leading to the development of selective 11β-HSD1 inhibitors. We examined the impact of the reversible competitive 11β-HSD1 inhibitor, AZD4017, on the metabolic profile in an overweight female cohort with idiopathic intracranial hypertension (IIH).

METHODS

We conducted a UK multicenter phase II randomized, double-blind, placebo-controlled trial of 12-week treatment with AZD4017. Serum markers of glucose homeostasis, lipid metabolism, renal and hepatic function, inflammation and androgen profiles were determined and examined in relation to changes in fat and lean mass by dual-energy X-ray absorptiometry.

RESULTS

Patients receiving AZD4017 showed significant improvements in lipid profiles (decreased cholesterol, increased high-density lipoprotein [HDL] and cholesterol/HDL ratio), markers of hepatic function (decreased alkaline phosphatase and gamma-glutamyl transferase), and increased lean muscle mass (1.8%, P < .001). No changes in body mass index, fat mass, and markers of glucose metabolism or inflammation were observed. Patients receiving AZD4017 demonstrated increased levels of circulating androgens, positively correlated with changes in total lean muscle mass.

CONCLUSIONS

These beneficial metabolic changes represent a reduction in risk factors associated with raised intracranial pressure and represent further beneficial therapeutic outcomes of 11β-HSD1 inhibition by AZD4017 in this overweight IIH cohort. In particular, beneficial changes in lean muscle mass associated with AZD4017 may reflect new applications for this nature of inhibitor in the management of conditions such as sarcopenia.

Emerging themes in idiopathic intracranial hypertension

PURPOSE

Idiopathic intracranial hypertension (IIH) is a rare disorder characterised by raised intracranial pressure. The underlying pathophysiology is mostly unknown and effective treatment is an unmet clinical need in this disease. This review evaluates key emerging themes regarding disease characteristics, mechanisms contributing to raised intracranial pressure and advances in potential therapeutic targets.

FINDINGS

IIH is becoming more common, with the incidence rising in parallel with the global obesity epidemic. Current medical management remains centred around weight management, which is challenging. Metabolic investigations of patients have identified specific androgen profiles in cerebrospinal fluid (CSF), which suggest an endocrine dysfunction impacting CSF secretion in IIH. Glucagon-like peptide-1 (GLP-1) and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) have been found to play a role in CSF dynamics in IIH and have formed the basis of the first clinical trials looking at new treatments.

CONCLUSIONS

Identification of novel molecular targets thought to underlie IIH pathology is now being translated to clinical trials.

Electroosmotic Perfusion-Microdialysis Probe Created by Direct Laser Writing for Quantitative Assessment of Leucine Enkephalin Hydrolysis by Insulin-Regulated Aminopeptidase in Vivo

There are many processes that actively alter the concentrations of solutes in the extracellular space. Enzymatic reactions, either by soluble enzymes or membrane-bound ectoenzymes, and uptake or clearance are two such processes. Investigations of ectoenzymatic reactions in vivo is challenging, particularly in the brain. Studies using microdialysis have revealed some qualitative information about what enzymes may be present, but microdialysis is a sampling technique so it is not designed to control conditions such as a substrate concentration outside the probe. Micropush-pull perfusion has been used to determine which nitric oxide synthase enzymes are active in discrete regions of the rat retina. Ectopeptidases are a particularly important class of ectoenzymes. As far as it is known, the extracellular activity of active peptides in the brain is controlled by ectopeptidases. To understand ectopeptidase activity, we developed a physical probe and an accompanying method. The probe has a two-channel source that supplies substrate or substrate plus inhibitor using electroosmotic perfusion (EOP). It also has a microdialysis probe to collect products and unreacted substrate. The method provides quantitative estimates of substrate-to-product conversion and the influence of inhibitors on this process. The quantitative estimates are made possible by including a d-amino acid-containing peptide analog of the substrate in the substrate-containing solution infused. Quantitative analysis of substrate, substrate analog, and products is carried out by quantitative, online capillary liquid chromatography-tandem mass spectrometry. The electroosmotic perfusion-microdialysis probe and associated method were used to determine the effect of the selective inhibitor HFI-419 on insulin-regulated aminopeptidase (EC 3.4.11.3) in the rat neocortex.

11β-hydroxysteroid dehydrogenase type 1 inhibitor use in human disease-a systematic review and narrative synthesis

INTRODUCTION

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is an intracellular enzyme that catalyses conversion of cortisone into cortisol; correspondingly, 11β-HSD1 inhibitors inhibit this conversion. This systematic review focuses on the use of 11β-HSD1 inhibitors in diseases known to be associated with abnormalities in hypothalamic pituitary adrenal (HPA) axis function.

METHODS

The databases screened for suitable papers were: MedLine, EMBASE, Web of Science, ClinicalTrials.gov, and Cochrane Central.

RESULTS

1925 papers were identified, of which 29 were included in the final narrative synthesis. 11β-HSD1 and its inhibitors have been studied in diabetes, obesity, metabolic syndrome (MetS), and Alzheimer's disease (AD). Higher expression of 11β-HSD1 is seen in obesity and MetS, but has not yet been described in obesity or AD. Genetic studies identify 11β-HSD1 SNPs of interest in populations with diabetes, MetS, and AD. One phase II trial successfully reduced HbA1c in a diabetic population, however trials in MetS, obesity, and AD have not met primary endpoints.

CONCLUSIONS

Translation of this research from preclinical studies has proved challenging so far, however this is a growing area of research and more studies should focus on understanding the complex relationships between 11β-HSD1 and disease pathology, especially given the therapeutic potential of 11β-HSD1 inhibitors in development.

Metabolic Concepts in Idiopathic Intracranial Hypertension and Their Potential for Therapeutic Intervention

BACKGROUND

Traditional risk factors associated with idiopathic intracranial hypertension (IIH) include obesity, weight gain, and female sex. The incidence of IIH is increasing and yet the underlying trigger and the fueling pathological mechanisms are still poorly understood.

EVIDENCE ACQUISITION

Review of ophthalmology, neurology, general surgery, obesity, endocrinology, nutrition, and neurosurgery literature was made.

RESULTS

The facts that implicate sex and obesity in IIH and headache are examined. The role of fat distribution in IIH is questioned, and the concept of adipose tissue functioning as an endocrine organ driving IIH is discussed. The impact of androgen metabolism in IIH is reviewed as is the emerging role of glucagon-like-peptide-1 analogues in modulating intracranial pressure. This introduces the concept of developing targeted disease-modifying therapeutic strategies for IIH.

CONCLUSIONS

This review will discuss the possible role of the adipose/gut/brain metabolism axis in IIH and speculate how this may impact the pathogenesis of IIH and therapeutic opportunities.

11β-Hydroxysteroid dehydrogenase type 1 inhibition in idiopathic intracranial hypertension: a double-blind randomized controlled trial

Treatment options for idiopathic intracranial hypertension are limited. The enzyme 11β-hydroxysteroid dehydrogenase type 1 has been implicated in regulating cerebrospinal fluid secretion, and its activity is associated with alterations in intracranial pressure in idiopathic intracranial hypertension. We assessed therapeutic efficacy, safety and tolerability and investigated indicators of in vivo efficacy of the 11β-hydroxysteroid dehydrogenase type 1 inhibitor AZD4017 compared with placebo in idiopathic intracranial hypertension. A multicenter, UK, 16-week phase II randomized, double-blind, placebo-controlled trial of 12-week treatment with AZD4017 or placebo was conducted. Women aged 18–55 years with active idiopathic intracranial hypertension (>25 cmH₂O lumbar puncture opening pressure and active papilledema) were included. Participants received 400 mg of oral AZD4017 twice daily compared with matching placebo over 12 weeks. The outcome measures were initial efficacy, safety and tolerability. The primary clinical outcome was lumbar puncture opening pressure at 12 weeks analysed by intention-to-treat. Secondary clinical outcomes were symptoms, visual function, papilledema, headache and anthropometric measures. In vivo efficacy was evaluated in the central nervous system and systemically. A total of 31 subjects [mean age 31.2 (SD = 6.9) years and body mass index 39.2 (SD = 12.6) kg/m²] were randomized to AZD4017 (n = 17) or placebo (n = 14). At 12 weeks, lumbar puncture pressure was lower in the AZD4017 group (29.7 cmH₂O) compared with placebo (31.3 cmH₂O), but the difference between groups was not statistically significant (mean difference: −2.8, 95% confidence interval: −7.1 to 1.5; P = 0.2). An exploratory analysis assessing mean change in lumbar puncture pressure within each group found a significant decrease in the AZD4017 group [mean change: −4.3 cmH₂O (SD = 5.7); P = 0.009] but not in the placebo group [mean change: −0.3 cmH₂O (SD = 5.9); P = 0.8]. AZD4017 was safe, with no withdrawals related to adverse effects. Nine transient drug-related adverse events were reported. One serious adverse event occurred in the placebo group (deterioration requiring shunt surgery). In vivo biomarkers of 11β-hydroxysteroid dehydrogenase type 1 activity (urinary glucocorticoid metabolites, hepatic prednisolone generation, serum and cerebrospinal fluid cortisol:cortisone ratios) demonstrated significant enzyme inhibition with the reduction in serum cortisol:cortisone ratio correlating significantly with reduction in lumbar puncture pressure (P = 0.005, R = 0.70). This is the first phase II randomized controlled trial in idiopathic intracranial hypertension evaluating a novel therapeutic target. AZD4017 was safe and well tolerated and inhibited 11β-hydroxysteroid dehydrogenase type 1 activity in vivo. Reduction in serum cortisol:cortisone correlated with decreased intracranial pressure. Possible clinical benefits were noted in this small cohort. A longer, larger study would now be of interest.

Ectopic lipid deposition mediates insulin resistance in adipose specific 11β-hydroxysteroid dehydrogenase type 1 transgenic mice

CONTEXT

Excessive adipose glucocorticoid action is associated with insulin resistance, but the mechanisms linking adipose glucocorticoid action to insulin resistance are still debated. We hypothesized that insulin resistance from excess glucocorticoid action may be attributed in part to increased ectopic lipid deposition in liver.

METHODS

We tested this hypothesis in the adipose specific 11β-hydroxysteroid dehydrogenase-1 (HSD11B1) transgenic mouse, an established model of adipose glucocorticoid excess. Tissue specific insulin action was assessed by hyperinsulinemic-euglycemic clamps, hepatic lipid content was measured, hepatic insulin signaling was assessed by immunoblotting. The role of hepatic lipid content was further probed by administration of the functionally liver-targeted mitochondrial uncoupler, Controlled Release Mitochondrial Protonophore (CRMP).

FINDINGS

High fat diet fed HSD11B1 transgenic mice developed more severe hepatic insulin resistance than littermate controls (endogenous suppression of hepatic glucose production was reduced by 3.8-fold, P < 0.05); this was reflected by decreased insulin-stimulated hepatic insulin receptor kinase tyrosine phosphorylation and AKT serine phosphorylation. Hepatic insulin resistance was associated with a 53% increase (P < 0.05) in hepatic triglyceride content, a 73% increase in diacylglycerol content (P < 0.01), and a 66% increase in PKCε translocation (P < 0.05). Hepatic insulin resistance was prevented with administration of CRMP by reversal of hepatic steatosis and prevention of hepatic diacylglycerol accumulation and PKCε activation.

CONCLUSIONS

These findings are consistent with excess adipose glucocorticoid activity being a predisposing factor for the development of lipid (diacylglycerol-PKCε)-induced hepatic insulin resistance.

Expression and activity of the cortisol-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 is tissue and species-specific

The microsomal enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts glucocorticoid receptor-inert cortisone (11-dehydrocorticosterone in rodents) to its receptor-active form cortisol (corticosterone in rodents). Thus, 11β-HSD1 amplifies glucocorticoid action at the tissue level. According to the current literature, dysregulation of glucocorticoid signaling may contribute to the pathogenesis of the metabolic syndrome in which regeneration of cortisol by 11β-HSD1 may be an important factor. This is why the enzyme has been very intensely investigated as a potential therapeutic target to treat metabolic complications such as obesity and diabetes type 2. However, due to controversial results from the various animal and human studies as well as from different findings with regard to tissue-specific expression and activity, the varied results unfortunately do not yield a consistent picture. Therefore, the precise role of 11β-HSD1 in the development of complications associated with the metabolic syndrome has still not been deciphered yet. Overall, the prominent role of this enzyme in the pathogenesis of the metabolic syndrome becomes more and more dubious and therefore further studies are necessary to clarify its role finally. This short review gives an overview on the main contradicting findings on the role of 11β-HSD1 in the development of visceral obesity and diabetes type 2.

Thiazolo[3,2-a]pyrimidin-5-one derivatives as a novel class of 11β-hydroxysteroid dehydrogenase inhibitors

11β-hydroxysteroid type 1 dehydrogenase (11β-HSD1) is an enzyme that increases tissue concentrations of cortisol. Selective inhibitors of this enzyme regulate the level of cortisol and thus play a key role in the treatment of Cushing's syndrome, metabolic syndrome and type 2 diabetes. In this study the inhibitory activity of 29 thiazolo[3,2-a]pyrimidin-5-one derivatives on 11β-HSD1 were investigated. Studies were carried out with pooled human liver microsomes. A lot of analyzed compounds show activity for inhibiting 11β-HSD1 (up to 59.15% at concentration 10 µmol/l). Molecular docking simulation show that the molecule of the most active compound: 7-(cyclohexylmethyl)-2-iodomethyl-2,3-dihydrothiazolo[3,2-a]pyrimidin-5-one forms hydrogen bonds with Ala172, Leu171, Leu215 or Tyr177. In addition, the cycloalkane moiety can create the hydrophobic contacts with NADP⁺. For this compound also the most favourable Docking Score value was obtained. The most active compound only in the slight degree inhibits 11β-HSD2 activity and is a selective inhibitor of 11β-hydroxysteroid dehydrogenase type 1. Consequently it can have a real effect on the regulation of the cortisol level in the body.

Methods of Measuring Enzyme Activity Ex Vivo and In Vivo

Enzymes catalyze a variety of biochemical reactions in the body and, in conjunction with transporters and receptors, control virtually all physiological processes. There is great value in measuring enzyme activity ex vivo and in vivo. Spatial and temporal differences or changes in enzyme activity can be related to a variety of natural and pathological processes. Several analytical approaches have been developed to meet this need. They can be classified broadly as methods either based on artificial substrates, with the goal of creating images of diseased tissue, or based on natural substrates, with the goal of understanding natural processes. This review covers a selection of these methods, including optical, magnetic resonance, mass spectrometry, and physical sampling approaches, with a focus on creative chemistry and method development that make ex vivo and in vivo measurements of enzyme activity possible.

Pulsatility of glucocorticoid hormones in pregnancy: Changes with gestation and obesity

OBJECTIVE

Hypothalamic-pituitary-adrenal axis (HPA) activity is decreased in obese pregnancy and associates with increased foetal size. Pulsatile release of glucocorticoid hormones regulates their action in target tissues. Glucocorticoids are essential for normal foetal growth, but little is known about glucocorticoid pulsatility in pregnancy. We aimed to investigate the ultradian rhythm of glucocorticoid secretion during obese and lean pregnancy and nonpregnancy.

DESIGN

Serum cortisol, cortisone, corticosterone and 11-dehydrocorticosterone were measured by LC-MS/MS from samples obtained at 10-minute intervals between 08.00-11.00 hours and 16.00-19.00 hours, from 8 lean (BMI <25 kg/m² ) and 7 obese (BMI > 35 kg/m² ) pregnant women between 16-24 weeks gestation and again at 30-36 weeks), and nonpregnant controls (lean n = 3, obese n = 4) during the luteal phase of their menstrual cycle. Interstitial fluid cortisol was measured by ELISA, from samples obtained using a portable microdialysis and automated collection device at 20-minute intervals over 24 hours.

RESULTS

Serum cortisol AUC, highest peak and lowest trough increased significantly with gestation in lean and obese pregnant compared with nonpregnant subjects. Pulsatility of cortisol was detected in interstitial fluid. In pregnant subjects, interstitial fluid pulse frequency was significantly lower with advancing gestation in obese, but not in lean.

CONCLUSIONS

We demonstrate cortisol pulsatility in interstitial fluid. Pulse frequency is altered with increased gestation and BMI. This may be a novel mechanism to explain decreased HPA activity in obese pregnancy.

Cortisol Stress Reactivity to the Trier Social Stress Test in Obese Adults

OBJECTIVE

Approximately 600 million adults worldwide suffer from obesity. In addition to individual's eating behavior and lack of physical activity in the development of obesity and overweight, psychosocial stress as well as hormonal stress reactivity must also be considered as important contributing factors. In the current study we compared the cortisol stress response pathway in a psychosocial stress induction (Trier Social Stress Test; TSST) with obese individuals and normal-weight controls.

METHOD

32 obese individuals (17 females; mean age = 33.94 years, SD = 11.31 years) and 32 normal-weight controls (17 females; mean age = 29.09 years, SD = 10.46 years) underwent the TSST. The salivary cortisol responses and three appraisal questionnaires (Primary Appraisal Secondary Appraisal, Visual Analogue Scale, Trier Inventory for Chronic Stress) were measured.

RESULTS

After stress induction, there was a significant main group difference between the obese individuals and the normal-weight controls for cortisol, with lower baseline and post-stress cortisol levels in the obese individuals. Nevertheless, the obese individuals as well as the normal-weight controls showed no significant difference in the self-reported assessment of the stress condition but some significant differences in the cognitive appraisal of the TSST.

CONCLUSION

In conclusion, the induction of psychosocial stress showed differences in the cortisol patterns between the obese individuals and the normal-weight controls. Furthermore, the present data suggest that obesity leads to lower cortisol activity, which may indicate alterations in the Hypothalamic-pituitary-adrencortical (HPA) axis.

Does stress influence sleep patterns, food intake, weight gain, abdominal obesity and weight loss interventions and vice versa?

Decades of research have reported only weak associations between the intakes of specific foods or drinks and weight gain and obesity. Randomized controlled dietary intervention trials have only shown very modest effects of changes in nutrient intake and diet composition on body weight in obese subjects. This review summarizes the scientific evidence on the role mental stress (either in or not in association with impaired sleep) may play in poor sleep, enhanced appetite, cravings and decreased motivation for physical activity. All these factors contribute to weight gain and obesity, possibly via decreasing the efficacy of weight loss interventions. We also review evidence for the role that lifestyle and stress management may play in achieving weight loss in stress-vulnerable individuals with overweight.

Quantification of 11β-hydroxysteroid dehydrogenase 1 kinetics and pharmacodynamic effects of inhibitors in brain using mass spectrometry imaging and stable-isotope tracers in mice

11β-Hydroxysteroid dehydrogenase 1 (11β-HSD1; EC 1.1.1.146) generates active glucocorticoid hormones. Small molecule inhibitors have been developed to target 11β-HSD1 for the treatment of dementia; these must enter brain subregions, such as the hippocampus, to be effective. We previously reported mass spectrometry imaging measurement of murine tissue steroids, and deuterated steroid tracer infusion quantification of 11β-HSD1 turnover in humans. Here, these tools are combined to assess tissue pharmacokinetics and pharmacodynamics of an 11β-HSD1 inhibitor that accesses the brain.

[9,11,12,12-²H]₄-Cortisol was infused (1.75 mg/day) by minipump for 2 days into C57Bl6 mice (male, age 12 weeks, n = 3/group) after which an 11β-HSD1 inhibitor (UE2316) was administered (25 mg/kg oral gavage) and animals culled immediately or 1, 2 and 4 h post-dosing. Mice with global genetic disruption of Hsd11B1 were studied similarly. Turnover of d4-cortisol to d3-cortisone (by loss of the 11-deuterium) and regeneration of d3-cortisol (by 11β-HSD1-mediated reduction) were assessed in plasma, liver and brain using matrix assisted laser desorption ionization coupled to Fourier transform cyclotron resonance mass spectrometry.

The tracer d4-cortisol was detected in liver and brain following a two day infusion. Turnover to d3-cortisone and on to d3-cortisol was slower in brain than liver. In contrast, d3-cortisol was not detected in mice lacking 11β-HSD1. UE2316 impaired d3-cortisol generation measured in whole body (assessed in plasma; 53.1% suppression in rate of appearance in d3-cortisol), liver and brain. Differential inhibition in brain regions was observed; active glucocorticoids were suppressed to a greater in extent hippocampus or cortex than in amygdala.

These data confirm that the contribution of 11β-HSD1 to the tissue glucocorticoid pool, and the consequences of enzyme inhibition on active glucocorticoid concentrations, are substantial, including in the brain. They further demonstrate the value of mass spectrometry imaging in pharmacokinetic and pharmacodynamic studies.

The cortisol-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 in skeletal muscle in the pathogenesis of the metabolic syndrome

The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) contributes to intracellular glucocorticoid action by converting inactive cortisone to its receptor-active form cortisol (11-dehydrocorticosterone and corticosterone in mice and rats). The potential role of 11β-HSD1 in the pathogenesis of the metabolic syndrome has emerged over the past three decades. However, the precise impact of 11β-HSD1 in obesity-related diseases remains uncertain. Many studies from animal experiments to clinical studies have investigated liver and adipose tissue 11β-HSD1 in relation to obesity and its metabolic disorders including insulin resistance. But the relevance of 11β-HSD1 in skeletal muscle has been less extensively studied. On the other hand, skeletal muscle is assumed to be the main site of peripheral insulin resistance, but the biological relevance of 11β-HSD1 in skeletal muscle is unclear. This mini-review will focus on 11β-HSD1 in skeletal muscle and its postulated link to obesity and insulin-resistance.

11β-Hydroxysteroid Dehydrogenase Type 1 in Obese Subjects With Type 2 Diabetes Mellitus

Obesity is one of the most significant contributors to the development of type 2 diabetes mellitus. Tissue-specific glucocorticoids regulated by 11β-hydroxysteroid dehydrogenase enzyme (11β-HSD) type 1 are involved in central obesity and obesity-related comorbidities. Moderate downregulation of 11β-HSD1 can attenuate insulin insensitivity and the impairment of glucose-stimulated insulin secretion. Some of the beneficial effects of 11β-HSD1 inhibition may be mediated, at least in part, through inactivation of tissue-specific glucocorticoid action related to insulin signaling mechanisms, alleviation of abnormal cytokine profile and the improvement of β-cell function. Thus, 11β-HSD1 is a promising target for the treatment and prevention of type 2 diabetes mellitus with obesity.

The Role of Essential Fatty Acids in Anorexia Nervosa and Obesity

The two basic questions in food intake study are what we eat, and how much do we eat. Most research is directed toward the control of how much is eaten. This is likely the result of the increased number of individuals with eating disorders in the Western world. Feeding behavior is highly complex, and is controlled by many psychological, physiological, biochemical, and immunological factors. The aim of this review is to clarify the involvement of fatty acids in eating disorders such as anorexia and binge eating disorder. The review will describe the modified fatty acid profile observed in individuals with anorexia or binge eating disorder, and discuss on what factors fatty acids can exert beneficial effects. In addition, the differences and similarities between anorexia and binge eating disorder will be discussed. We suggest that beneficial effects of essential fatty acids on both anorexia and binge eating disorder can be explained by the stabilizing effect of those fatty acids on the neuronal membrane fluidity index.

Mass spectrometry and its evolving role in assessing tissue specific steroid metabolism

Glucocorticoid hormones play vital roles in regulating diverse biological processes in health and disease. Tissue levels are regulated by enzymes which activate and inactivate hormones. The enzyme, 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1), in particular, has been identified as a potential drug target; inhibiting this enzyme attenuates glucocorticoid action by lowering local levels of active hormone. A variety of mass spectrometric approaches have been developed to characterize this enzymein vivo Endogenous glucocorticoids and their metabolites can be profiled in urine by GC-MS and circulating steroids are now more commonly quantified by liquid chromatography tandem mass spectrometry. Tracer dilution studies have allowed rates of generation of glucocorticoids by the enzyme to be distinguished from hormone generated directly by the adrenal glands and, in combination with arterio-venous (AV) sampling, rates of production by specific tissues have been quantified. This has allowed the contribution of liver, adipose, muscle and brain to cortisol production in metabolic disease and hence prioritized drug targets. Most recently MS imaging in combination with on-tissue derivatization has been developed to profile oxo-steroids in tissue sections, allowing molecular maps to be generated across complex tissues, where regional functions are important. The review provides a synopsis of how measurement of steroids by MS has evolved with technological advances and this has provided insight into the dynamic turnover of glucocorticoidsin vivo, highlighting the milestones that have advanced the field and identifying the remaining challenges for researchers, in terms of analytical chemistry and endocrine physiology and biochemistry.

Metformin Increases Cortisol Regeneration by 11βHSD1 in Obese Men With and Without Type 2 Diabetes Mellitus

CONTEXT

The mechanism of action of metformin remains unclear. Given the regulation of the cortisol-regenerating enzyme 11βhydroxysteroid dehydrogenase 1 (11βHSD1) by insulin and the limited efficacy of selective 11βHSD1 inhibitors to lower blood glucose when co-prescribed with metformin, we hypothesized that metformin reduces 11βHSD1 activity.

OBJECTIVE

To determine whether metformin regulates 11βHSD1 activity in vivo in obese men with and without type 2 diabetes mellitus.

DESIGN

Double-blind, randomized, placebo-controlled, crossover study.

SETTING

A hospital clinical research facility.

PARTICIPANTS

Eight obese nondiabetic (OND) men and eight obese men with type 2 diabetes (ODM).

INTERVENTION

Participants received 28 days of metformin (1 g twice daily), placebo, or (in the ODM group) gliclazide (80 mg twice daily) in random order. A deuterated cortisol infusion at the end of each phase measured cortisol regeneration by 11βHSD1. Oral cortisone was given to measure hepatic 11βHSD1 activity in the ODM group. The effect of metformin on 11βHSD1 was also assessed in human hepatocytes and Simpson-Golabi-Behmel syndrome adipocytes.

MAIN OUTCOME MEASURES

The effect of metformin on whole-body and hepatic 11βHSD1 activity.

RESULTS

Whole-body 11βHSD1 activity was approximately 25% higher in the ODM group than the OND group. Metformin increased whole-body cortisol regeneration by 11βHSD1 in both groups compared with placebo and gliclazide and tended to increase hepatic 11βHSD1 activity. In vitro, metformin did not increase 11βHSD1 activity in hepatocytes or adipocytes.

CONCLUSIONS

Metformin increases whole-body cortisol generation by 11βHSD1 probably through an indirect mechanism, potentially offsetting other metabolic benefits of metformin. Co-prescription with metformin should provide a greater target for selective 11βHSD1 inhibitors.

Aromatase Inhibition Reduces Insulin Sensitivity in Healthy Men

CONTEXT

Deficiency of aromatase, the enzyme that catalyzes the conversion of androgens to estrogens, is associated with insulin resistance in humans and mice.

OBJECTIVE

We hypothesized that pharmacological aromatase inhibition results in peripheral insulin resistance in humans.

DESIGN

This was a double-blind, randomized, controlled, crossover study.

SETTING

The study was conducted at a clinical research facility.

PARTICIPANTS

Seventeen healthy male volunteers (18-50 y) participated in the study.

INTERVENTION

The intervention included oral anastrozole (1 mg daily) and placebo, each for 6 weeks with a 2-week washout period.

MAIN OUTCOME MEASURE

Glucose disposal and rates of lipolysis were measured during a stepwise hyperinsulinemic euglycemic clamp. Data are mean (SEM).

RESULTS

Anastrozole therapy resulted in significant estradiol suppression (59.9 ± 3.6 vs 102.0 ± 5.7 pmol/L, P = < .001) and a more modest elevation of total T (25.8 ± 1.2 vs 21.4 ± 0.7 nmol/L, P = .003). Glucose infusion rate, during the low-dose insulin infusion, was lower after anastrozole administration (12.16 ± 1.33 vs 14.15 ± 1.55 μmol/kg·min, P = .024). No differences in hepatic glucose production or rate of lipolysis were observed.

CONCLUSION

Aromatase inhibition reduces insulin sensitivity, with respect to peripheral glucose disposal, in healthy men. Local generation and action of estradiol, at the level of skeletal muscle, is likely to be an important determinant of insulin sensitivity.

Idiopathic intracranial hypertension, hormones, and 11β-hydroxysteroid dehydrogenases

Idiopathic intracranial hypertension (IIH) results in raised intracranial pressure (ICP) leading to papilledema, visual dysfunction, and headaches. Obese females of reproductive age are predominantly affected, but the underlying pathological mechanisms behind IIH remain unknown. This review provides an overview of pathogenic factors that could result in IIH with particular focus on hormones and the impact of obesity, including its role in neuroendocrine signaling and driving inflammation. Despite occurring almost exclusively in obese women, there have been a few studies evaluating the mechanisms by which hormones and adipokines exert their effects on ICP regulation in IIH. Research involving 11β-hydroxysteroid dehydrogenase type 1, a modulator of glucocorticoids, suggests a potential role in IIH. Improved understanding of the complex interplay between adipose signaling factors such as adipokines, steroid hormones, and ICP regulation may be key to the understanding and future management of IIH.

Hypothalamic-pituitary-adrenal axis dysregulation and cortisol activity in obesity: A systematic review

BACKGROUND

Although there is substantial evidence of differential hypothalamic-pituitary-adrenal (HPA) axis activity in both generalized and abdominal obesity, consistent trends in obesity-related HPA axis perturbations have yet to be identified.

OBJECTIVES

To systematically review the existing literature on HPA activity in obesity, identify possible explanations for inconsistencies in the literature, and suggest methodological improvements for future study.

DATA SOURCES

Included papers used Pubmed, Google Scholar, and the University of California Library search engines with search terms body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, sagittal diameter, abdominal versus peripheral body fat distribution, body fat percentage, DEXA, abdominal obesity, and cortisol with terms awakening response, slope, total daily output, reactivity, feedback sensitivity, long-term output, and 11β-HSD expression.

STUDY ELIGIBILITY CRITERIA

Empirical research papers were eligible provided that they included at least one type of obesity (general or abdominal), measured at least one relevant cortisol parameter, and a priori tested for a relationship between obesity and cortisol.

RESULTS

A general pattern of findings emerged where greater abdominal fat is associated with greater responsivity of the HPA axis, reflected in morning awakening and acute stress reactivity, but some studies did show underresponsiveness. When examined in adipocytes, there is a clear upregulation of cortisol output (due to greater expression of 11β-HSD1), but in hepatic tissue this cortisol is downregulated. Overall obesity (BMI) appears to also be related to a hyperresponsive HPA axis in many but not all studies, such as when acute reactivity is examined.

LIMITATIONS

The reviewed literature contains numerous inconsistencies and contradictions in research methodologies, sample characteristics, and results, which partially precluded the development of clear and reliable patterns of dysregulation in each investigated cortisol parameter.

CONCLUSIONS AND IMPLICATIONS

The literature to date is inconclusive, which may well arise from differential effects of generalized obesity vs. abdominal obesity or from modulators such as sex, sex hormones, and chronic stress. While the relationship between obesity and adipocyte cortisol seems to be clear, further research is warranted to understand how adipocyte cortisol metabolism influences circulating cortisol levels and to establish consistent patterns of perturbations in adrenal cortisol activity in both generalized and abdominal obesity.

A potent and selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor, SKI2852, ameliorates metabolic syndrome in diabetic mice models

11β-Hydroxysteroid dehydrogenase type 1 (11βHSD1) has been targeted for new drugs to treat type 2 diabetes and metabolic syndrome. In this study, we determined whether the inhibition of 11βHSD1 with a new selective inhibitor, SKI2852, could improve lipid profiles, glucose levels, and insulin sensitivity in type 2 diabetic and obese conditions. SKI2852 showed a potent inhibition of cortisone to cortisol conversion for over 80% in both liver and adipose tissue ex vivo from orally administered C57BL/6 mice, and in vivo analysis results were consistent with this. Repeated oral administrations of SKI2852 in diet-induced obesity (DIO) and ob/ob mice revealed a partially beneficial effect of SKI2852 in improving levels of cholesterols, triglycerides, free fatty acids, postprandial glucose, and/or blood hemoglobinA1c. SKI2852 significantly reduced body weight increase in ob/ob mice, and efficiently suppressed hepatic mRNA levels of gluconeogenic enzymes in DIO mice. Moreover, SKI2852 enhanced hepatic and whole body insulin sensitivities in hyperinsulinemic-euglycemic clamp experiment in DIO mice. In conclusion, these results indicate that selective and potent inhibition of 11βHSD1 by SKI2852, thus blockade of active glucocorticoid conversion, may improve many aspects of metabolic parameters in type 2 diabetes and metabolic diseases, mainly by inhibitions of hepatic gluconeogenesis and partial improvements of lipid profiles. Our study strongly support that SKI2852 may have a great potential as a novel candidate drug for the treatment of diabetes and metabolic diseases.

Effects of Carbenoxolone on the Canine Pituitary-Adrenal Axis

Cushing’s disease caused by pituitary corticotroph adenoma is a common endocrine disease in dogs. A characteristic biochemical feature of corticotroph adenomas is their relative resistance to suppressive negative feedback by glucocorticoids. The abnormal expression of 11beta-hydroxysteroid dehydrogenase (11HSD), which is a cortisol metabolic enzyme, is found in human and murine corticotroph adenomas. Our recent studies demonstrated that canine corticotroph adenomas also have abnormal expression of 11HSD. 11HSD has two isoforms in dogs, 11HSD type1 (HSD11B1), which converts cortisone into active cortisol, and 11HSD type2 (HSD11B2), which converts cortisol into inactive cortisone. It has been suggested that glucocorticoid resistance in corticotroph tumors is related to the overexpression of HSD11B2. Therefore it was our aim to investigate the effects of carbenoxolone (CBX), an 11HSD inhibitor, on the healthy dog’s pituitary-adrenal axis. Dogs were administered 50 mg/kg of CBX twice each day for 15 days. During CBX administration, no adverse effects were observed in any dogs. The plasma adrenocorticotropic hormone (ACTH), and serum cortisol and cortisone concentrations were significantly lower at day 7 and 15 following corticotropin releasing hormone stimulation. After completion of CBX administration, the HSD11B1 mRNA expression was higher, and HSD11B2 mRNA expression was significantly lower in the pituitaries. Moreover, proopiomelanocortin mRNA expression was lower, and the ratio of ACTH-positive cells in the anterior pituitary was also significantly lower after CBX treatment. In adrenal glands treated with CBX, HSD11B1 and HSD11B2 mRNA expression were both lower compared to normal canine adrenal glands. The results of this study suggested that CBX inhibits ACTH secretion from pituitary due to altered 11HSD expressions, and is potentially useful for the treatment of canine Cushing’s disease.

Genistein inhibits glucocorticoid amplification in adipose tissue by suppression of 11β-hydroxysteroid dehydrogenase type 1

Excess glucocorticoids promote visceral obesity, hyperlipidemia, and insulin resistance. The main regulator of intracellular glucocorticoid levels is 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which converts inactive glucocorticoids into bioactive forms such as cortisol in humans and corticosterone in rodents. Hexose-6-phosphate dehydrogenase (H6PD), which is colocalized with 11β-HSD1 in the intralumen of the endoplasmic reticulum, supplies a crucial coenzyme, NADPH, for full reductase activity of 11β-HSD1. Therefore, it is possible that inhibition of 11β-HSD1 will become a considerable medical treatment for metabolic diseases including obesity and diabetes. Genistein, a soy isoflavone, has received attention for its therapeutic potential for obesity, diabetes, and cardiovascular disease, and has been proposed as a promising compound for the treatment of metabolic disorders. However, the mechanisms underlying the pleiotropic anti-obesity effects of genistein have not been fully clarified. Here, we demonstrate that genistein was able to inhibit 11β-HSD1 and H6PD activities within 10 or 20min, in dose- and time-dependent manners. Inhibition of 11β-HSD2 activity was not observed in rat kidney microsomes. The inhibition was not reversed by two estrogen receptor antagonists, tamoxifen and ICI182,780. A kinetic study revealed that genistein acted as a non-competitive inhibitor of 11β-HSD1, and its apparent Km value for 11-dehydrocorticosterone was 0.5μM. Genistein also acted as a non-competitive inhibitor of H6PD, and its apparent Km values for G6P and NADP were 0.9 and 3.3μM, respectively. These results suggest that genistein may exert its inhibitory effect by interacting with these enzymes.

11β-hydroxysteroid dehydrogenase types 1 and 2 activity in subcutaneous adipose tissue in humans: implications in obesity and diabetes

CONTEXT

The role of 11β-hydroxysteroid dehydrogenase types 1 (11β-HSD-1) and 2 (11β-HSD-2) enzymes in sc adipose tissue is controversial.

OBJECTIVE

The objective of the study was to determine the activity of 11β-HSD-1 and -2 enzymes in the abdominal and leg sc adipose tissue in obesity and diabetes.

DESIGN

11β-HSD-1 and -2 enzyme activities in abdominal and leg sc adipose tissue were measured by infusing [2,2,4,6,6,12,12-(2)H7] cortisone (D7 cortisone) and [9,12,12-(2)H3] cortisol (D3 cortisol) via microdialysis catheters placed in sc fat depots.

SETTING

The study was conducted at the Mayo Clinic Clinical Research Unit.

PARTICIPANTS

Lean nondiabetic (n = 13), overweight/obese nondiabetic (n = 15), and overweight/obese participants with type 2 diabetes mellitus (n = 15) participated in the study.

MAIN OUTCOME MEASURES

The conversion of infused D7 cortisone to D7 cortisol (via 11β-HSD reductase activity) and D3 cortisol to D3 cortisone (via 11β-HSD dehydrogenase activity) in sc adipose tissue.

RESULTS

Enrichment of D7 cortisone and D3 cortisol were similar in the effluents from both sites in all groups. D3 cortisone enrichment did not differ in the three cohorts, indicating that 11β-HSD-2 enzyme activity (conversion of cortisol to cortisone) occurs equally in all groups. However, D7 cortisol enrichment was detectable in abdominal sc fat of overweight/obese participants with type 2 diabetes mellitus only, implying 11β-HSD-1 reductase activity (conversion of cortisone to cortisol) occurs in obese subjects with type 2 diabetes.

CONCLUSIONS

There is conversion of cortisone to cortisol via the 11β-HSD-1 enzyme pathway in abdominal sc fat depots in overweight/obese participants with type 2 diabetes mellitus. This observation has significant implications for developing tissue-specific 11β-HSD-1 inhibitors in type 2 diabetes mellitus.

Effect of restorative yoga vs. stretching on diurnal cortisol dynamics and psychosocial outcomes in individuals with the metabolic syndrome: the PRYSMS randomized controlled trial

PURPOSE

Chronic stimulation and dysregulation of the neuroendocrine system by stress may cause metabolic abnormalities. We estimated how much cortisol and psychosocial outcomes improved with a restorative yoga (relaxation) versus a low impact stretching intervention for individuals with the metabolic syndrome.

METHODS

We conducted a 1-year multi-center randomized controlled trial (6-month intervention and 6-month maintenance phase) of restorative yoga vs. stretching. Participants completed surveys to assess depression, social support, positive affect, and stress at baseline, 6 months and 12 months. For each assessment, we collected saliva at four points daily for three days and collected response to dexamethasone on the fourth day for analysis of diurnal cortisol dynamics. We analyzed our data using multivariate regression models, controlling for study site, medications (antidepressants, hormone therapy), body mass index, and baseline cortisol values.

RESULTS

Psychosocial outcome measures were available for 171 study participants at baseline, 140 at 6 months, and 132 at 1 year. Complete cortisol data were available for 136 of 171 study participants (72 in restorative yoga and 64 in stretching) and were only available at baseline and 6 months. At 6 months, the stretching group had decreased cortisol at waking and bedtime compared to the restorative yoga group. The pattern of changes in stress mirrored this improvement, with the stretching group showing reductions in chronic stress severity and perseverative thoughts about their stress. Perceived stress decreased by 1.5 points (-0.4; 3.3, p=0.11) at 6 months, and by 2.0 points (0.1; 3.9, p=0.04) at 1 year in the stretching compared to restorative yoga groups. Post hoc analyses suggest that in the stretching group only, perceived increases in social support (particularly feelings of belonging), but not changes in stress were related to improved cortisol dynamics.

CONCLUSIONS

We found significant decreases in salivary cortisol, chronic stress severity, and stress perception in the stretching group compared to the restorative yoga group. Group support during the interactive stretch classes may have contributed to these changes.

New molecular targets in the pathophysiology of obesity and available treatment options under investigation

The pharmacotherapy of obesity has historically recorded an overall poor safety and efficacy profile largely because of the complex mechanisms involved in the pathophysiology of obesity. It is hoped that a better understanding of the regulation of body weight will lead us to the development of effective and safer drugs. Recent advances in our understanding of the regulation of energy homeostasis has allowed the design of novel anti-obesity drugs targeting specific molecules crucial for the modulation of energy balance, including drugs that induce satiety, modulate nutrient absorption or influence metabolism or lipogenesis. Almost a decade after the Food and Drug Administration approved the first weight loss medication, it recently approved two novel anti-obesity drugs Belviq (lorcaserin) and Qsymia (topiramate and phentermine), thus signalling the beginning of a new era in the pharmacotherapy of obesity. It is believed that the next generation of weight-loss drugs will be based on combination treatments with gut hormones in a manner that mimics the changes underlying surgically induced weight loss thus introducing the so called 'bariatric pharmacotherapy'. An in-depth understanding of the interrelated physiological and behavioural effects of these new molecules together with the development of new treatment paradigms is needed so that future disappointments in the field of obesity pharmacotherapy may be avoided.

5α-reductase type 1 modulates insulin sensitivity in men

CONTEXT

5α-Reductase (5αR) types 1 and 2 catalyze the A-ring reduction of steroids, including androgens and glucocorticoids. 5α-R inhibitors lower dihydrotestosterone in benign prostatic hyperplasia; finasteride inhibits 5αR2, and dutasteride inhibits both 5αR2 and 5αR1. In rodents, loss of 5αR1 promotes fatty liver.

OBJECTIVE

Our objective was to test the hypothesis that inhibition of 5αR1 causes metabolic dysfunction in humans.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind randomized controlled parallel group study at a clinical research facility included 46 men (20-85 years) studied before and after intervention.

INTERVENTION

Oral dutasteride (0.5 mg daily; n = 16), finasteride (5 mg daily; n = 16), or control (tamsulosin; 0.4 mg daily; n = 14) was administered for 3 months.

MAIN OUTCOME MEASURE

Glucose disposal was measured during a stepwise hyperinsulinemic-euglycemic clamp. Data are mean (SEM).

RESULTS

Dutasteride and finasteride had similar effects on steroid profiles, with reduced urinary androgen and glucocorticoid metabolites and reduced circulating DHT but no change in plasma or salivary cortisol. Dutasteride, but not finasteride, reduced stimulation of glucose disposal by high-dose insulin (dutasteride by -5.7 [3.2] μmol/kg fat-free mass/min, versus finasteride +7.2 [3.0], and tamsulosin +7.0 [2.0]). Dutasteride also reduced suppression of nonesterified fatty acids by insulin and increased body fat (by 1.6% [0.6%]). Glucose production and glycerol turnover were unchanged. Consistent with metabolic effects of dutasteride being mediated in peripheral tissues, mRNA for 5αR1 but not 5αR2 was detected in human adipose tissue.

CONCLUSION

Dual inhibition of 5αRs, but not inhibition of 5αR2 alone, modulates insulin sensitivity in human peripheral tissues rather than liver. This may have important implications for patients prescribed dutasteride for prostatic disease.

Tissue-specific dysregulation of 11β-hydroxysteroid dehydrogenase type 1 in overweight/obese women with polycystic ovary syndrome compared with weight-matched controls

CONTEXT

Abnormal cortisol metabolism in polycystic ovary syndrome (PCOS) has been invoked as a cause of secondary activation of the hypothalamic-pituitary-adrenal axis and hence androgen excess. However, this is based on urinary excretion of cortisol metabolites, which cannot detect tissue-specific changes in metabolism and may be confounded by obesity.

OBJECTIVE

To assess cortisol clearance and whole-body and tissue-specific activities of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1 (HSD11B1)) in PCOS.

DESIGN

Case-control study.

SETTING

Medical center.

PATIENTS

A total of 20 overweight-obese unmedicated Caucasian women with PCOS, aged 18-45 years, and 20 Caucasian controls matched for age, BMI, body fat distribution, and HSD11B1 genotypes (rs846910 and rs12086634).

MAIN OUTCOME MEASURES

Cortisol metabolites were measured in 24 h urine. During steady-state 9,11,12,12-[(2)H]4-cortisol infusion, cortisol clearance was calculated and whole-body HSD11B1 activity was assessed as the rate of appearance of 9,12,12-(2)H3-cortisol (d3-cortisol). Hepatic HSD11B1 activity was quantified as the generation of plasma cortisol following an oral dose of cortisone. Subcutaneous adipose HSD11B1 activity and HSD11B1 mRNA were measured, ex vivo, in biopsies.

RESULTS

Urinary cortisol metabolite excretion, deuterated cortisol clearance, and the rate of appearance of d3-cortisol did not differ between patients with PCOS and controls. However, hepatic HSD11B1 conversion of oral cortisone to cortisol was impaired (P<0.05), whereas subcutaneous abdominal adipose tissue HSD11B1 mRNA levels and activity were increased (P<0.05) in women with PCOS when compared with controls.

CONCLUSIONS

Tissue-specific dysregulation of HSD11B1 is a feature of PCOS, over and above obesity, whereas increased clearance of cortisol may result from obesity rather than PCOS.

Tissue-specific dysregulation of cortisol regeneration by 11βHSD1 in obesity: has it promised too much?

Cushing's syndrome, caused by increased production of cortisol, leads to metabolic dysfunction including visceral adiposity, hypertension, hyperlipidaemia and type 2 diabetes. The similarities with the metabolic syndrome are striking and major efforts have been made to find obesity-associated changes in the regulation of glucocorticoid action and synthesis, both at a systemic level and tissue level. Obesity is associated with tissue-specific alterations in glucocorticoid metabolism, with increased activity of the glucocorticoid-regenerating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) in subcutaneous adipose tissue and decreased conversion of cortisone to cortisol, interpreted as decreased 11βHSD1 activity, in the liver. In addition, genetic manipulation of 11βHSD1 activity in rodents can either induce (by overexpression of Hsd11b1, the gene encoding 11βHSD1) or prevent (by knocking out Hsd11b1) obesity and metabolic dysfunction. Taken together with earlier evidence that non-selective inhibitors of 11βHSD1 enhance insulin sensitivity, these results led to the hypothesis that inhibition of 11βHSD1 might be a promising target for treatment of the metabolic syndrome. Several selective 11βHSD1 inhibitors have now been developed and shown to improve metabolic dysfunction in patients with type 2 diabetes, but the small magnitude of the glucose-lowering effect has precluded their further commercial development.This review focuses on the role of 11βHSD1 as a tissue-specific regulator of cortisol exposure in obesity and type 2 diabetes in humans. We consider the potential of inhibition of 11βHSD1 as a therapeutic strategy that might address multiple complications in patients with type 2 diabetes, and provide our thoughts on future directions in this field.

11β-HSD1 inhibitors for the treatment of type 2 diabetes and cardiovascular disease

Inhibition of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) has been proposed as a novel therapeutic target for the treatment of type 2 diabetes mellitus. Over 170 new compounds targeting 11β-HSD1 have been developed. This article reviews the current published literature on compounds that have reached phase II clinical trials in patients with type 2 diabetes, and summarises the preclinical evidence that such agents may be useful for associated conditions, including peripheral vascular disease, coronary artery disease and cognitive decline. In clinical trials, 11β-HSD1 inhibitors have been well tolerated and have improved glycaemic control, lipid profile and blood pressure, and induced modest weight loss. The magnitude of the effects are small relative to other agents, so that further development of 11β-HSD1 inhibitors for the primary therapeutic indication of type 2 diabetes has stalled. Ongoing programmes are focused on additional benefits for cognitive function and other cardiovascular risk factors.

Changes in adipose glucocorticoid metabolism before and after bariatric surgery assessed by direct hormone measurements

OBJECTIVES

Increased intra-adipose cortisol is thought to promote obesity, but few human studies have investigated intra-adipose glucocorticoid hormones and none have demonstrated prospective changes with fat loss.

DESIGN AND METHODS

Subcutaneous adipose tissue (SAT) was obtained from obese subjects before and 1-year after surgery-induced fat loss, and from nonobese controls. In a second similar cohort of obese subjects, adipocytes and stromal-vascular fraction were isolated. Intra-adipose cortisol and cortisone levels were analyzed by liquid chromatography mass spectrometry and HSD11B1/HSD11B2 mRNA by qPCR.

RESULTS

SAT cortisol/cortisone ratio before fat loss, median 4.8 (interquartile range, 4.1-5.7), was higher than after fat loss, 1.9 (1.0-2.7) (P = 0.001), and compared to nonobese controls, 3.2 (2.4-3.9) (P = 0.005). Cortisone before fat loss, 2.3 (1.2-2.9) nmol/kg, was lower than after fat loss, 5.8 (3.0-10.2) nmol/kg (P = 0.042), and compared to controls, 5.1 (3.8-6.7) nmol/kg (P = 0.013). HSD11B1 was predominantly expressed in mature adipocytes, whereas HSD11B2 was expressed at a higher level in stromal-vascular fraction.

CONCLUSIONS

The intra-adipose glucocorticoid metabolism was markedly altered in the extremely obese state with increased cortisol levels relative to cortisone, whereas fat loss restored this balance approximating nonobese subjects. Changes were more pronounced for cortisone than cortisol, suggesting an adaptive response to insufficient intra-adipose cortisol levels in obesity.