Efficient, multi-hundred-gram scale access to E3 ubiquitin ligase ligands for degrader development

Small molecule heterobifunctional degraders (commonly also known as PROTACs) offer tremendous potential to deliver new therapeutics in areas of unmet medical need. To deliver on this promise, a new discipline directed at degrader design and optimization has emerged within medicinal chemistry to address a central challenge, namely how to optimize relatively large, heterobifunctional molecules for activity, whilst maintaining drug-like properties. This process involves simultaneous optimization of the three principle degrader components: E3 ubiquitin ligase ligand, linker, and protein of interest (POI) ligand. A substantial degree of commonality exists with the E3 ligase ligands typically used at the early stages of degrader development, resulting in demand for these compounds as chemical building blocks in degrader research programs. We describe herein a collation of large scale, high-yielding syntheses to access the most utilized E3 ligase ligands to support early-stage degrader development.

Recycling glucocorticoids: therapeutic implications of the 11β-HSD1 enzyme system

Endogenous glucocorticoids and commonly used oral glucocorticoids have the property of existing in an inactive and active form in vivo. The inactive form can be converted back to the active form, or 'recycled' in cells and tissues that express the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. This recycling provides an important contribution to the action of glucocorticoids. This review examines the literature relating to the importance of 11β-HSD1 activity during glucocorticoid treatment with an emphasis on studies examining bone and joint disease and the ability of glucocorticoids to suppress inflammatory damage in models of arthritis. Animal models with global or selective deletion of 11β-HSD1 have determined the extent to which this recycling is important in normal physiology and during treatment with oral glucocorticoids. These studies demonstrate that 11β-HSD1 mediated recycling of inactive glucocorticoids has a substantial action and indeed is responsible for the majority of the effects of orally administered glucocorticoids on a range of tissues. Importantly, the anti-inflammatory actions of glucocorticoids appear largely through this mechanism such that mice that lack 11β-HSD1 are resistant to the anti-inflammatory actions of glucocorticoids. The recognition that to a large extent the circulating inactive counterpart of these glucocorticoids is more important to anti-inflammatory effects than the active glucocorticoid presents novel opportunities to more selectively target glucocorticoids to tissues or to reduce the likely side effects.

Glucocorticoid-Induced Psychosis in Children and Adolescents: A Systematic Review

Objectives: Knowledge is limited regarding the adverse effects of therapeutic glucocorticoids on pediatric mental health outcomes. Glucocorticoid-induced psychosis (GIP) is a rare but severe side effect of high-dose glucocorticoid therapy in children and adolescents. This study identified reported pediatric cases of GIP, based on DSM-5 criteria, and defined its presentation, treatments, and outcomes. Methods: A systematic review was completed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, including pediatric patients with incident psychosis following glucocorticoid treatment. Patient demographics, clinical presentation, interventions, outcomes, and long-term management were extracted from individual cases. Results: Of 1131 articles screened, 28 reports were included, comprising of 31 patients. The mean age was 13 years, and 61% of patients were male. The most common medical illnesses requiring administration of high dose glucocorticoids were asthma (23%) and acute lymphoblastic leukemia (23%). The most common glucocorticoid used was prednisone (35%), and most patients (91%) received doses greater than or equal to 40 mg/day of prednisone. The range of time to symptom onset was 1 day to 7 months. Hallucinations alone (45%) were the most reported feature of GIP. Glucocorticoids were discontinued in 52% of cases, reduced in dosage in 32%, and 81% of affected patients were prescribed psychotropic medications. Long-term management plans and prophylactic psychotropic use were not mentioned in 52% of cases. Symptoms resolved in 90% of patients, and the majority (71%) had no recurrence of psychiatric symptoms. Conclusions: GIP can generally be managed by tapering the causative agent with adjunctive second-generation antipsychotics if psychotic symptoms persist. All patients in this review had complete resolution or improvement of their psychotic symptoms; however, there is likely reporting bias due to the expected underreporting of negative outcomes. Managing clinicians must take a circumspect approach when prescribing high-dose glucocorticoids to minimize the risk of serious but preventable side effects.

Skin 11β-hydroxysteroid dehydrogenase type 1 enzyme expression regulates burn wound healing and can be targeted to modify scar characteristics

BACKGROUND

Excessive scarring and fibrosis are the most severe and common complications of burn injury. Prolonged exposure to high levels of glucocorticoids detrimentally impacts on skin, leading to skin thinning and impaired wound healing. Skin can generate active glucocorticoids locally through expression and activity of the 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1). We hypothesised that burn injury would induce 11β-HSD1 expression and local glucocorticoid metabolism, which would have important impacts on wound healing, fibrosis and scarring. We additionally proposed that pharmacological manipulation of this system could improve aspects of post-burn scarring.

METHODS

Skin 11β-HSD1 expression in burns patients and mice was examined. The impacts of 11β-HSD1 mediating glucocorticoid metabolism on burn wound healing, scar formation and scar elasticity and quality were additionally examined using a murine 11β-HSD1 genetic knockout model. Slow-release scaffolds containing therapeutic agents, including active and inactive glucocorticoids, were developed and pre-clinically tested in mice with burn injury.

RESULTS

We demonstrate that 11β-HSD1 expression levels increased substantially in both human and mouse skin after burn injury. 11β-HSD1 knockout mice experienced faster wound healing than wild type mice but the healed wounds manifested significantly more collagen deposition, tensile strength and stiffness, features characteristic of excessive scarring. Application of slow-release prednisone, an inactive glucocorticoid, slowed the initial rate of wound closure but significantly reduced post-burn scarring via reductions in inflammation, myofibroblast generation, collagen production and scar stiffness.

CONCLUSIONS

Skin 11β-HSD1 expression is a key regulator of wound healing and scarring after burn injury. Application of an inactive glucocorticoid capable of activation by local 11β-HSD1 in skin slows the initial rate of wound closure but significantlyimproves scar characteristics post burn injury.

Diastereomeric Resolution Yields Highly Potent Inhibitor of SARS-CoV-2 Main Protease

SARS-CoV-2 is the causative agent behind the COVID-19 pandemic. The main protease (Mpro, 3CLpro) of SARS-CoV-2 is a key enzyme that processes polyproteins translated from the viral RNA. Mpro is therefore an attractive target for the design of inhibitors that block viral replication. We report the diastereomeric resolution of the previously designed SARS-CoV-2 Mpro α-ketoamide inhibitor 13b. The pure (S,S,S)-diastereomer, 13b-K, displays an IC50 of 120 nM against the Mpro and EC50 values of 0.8-3.4 μM for antiviral activity in different cell types. Crystal structures have been elucidated for the Mpro complexes with each of the major diastereomers, the active (S,S,S)-13b (13b-K), and the nearly inactive (R,S,S)-13b (13b-H); results for the latter reveal a novel binding mode. Pharmacokinetic studies show good levels of 13b-K after inhalative as well as after peroral administration. The active inhibitor (13b-K) is a promising candidate for further development as an antiviral treatment for COVID-19.

11β-Hydroxysteroid Dehydrogenase Type 1 within Osteoclasts Mediates the Bone Protective Properties of Therapeutic Corticosteroids in Chronic Inflammation

Therapeutic glucocorticoids (GCs) are powerful anti-inflammatory tools in the management of chronic inflammatory diseases such as rheumatoid arthritis (RA). However, their actions on bone in this context are complex. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a mediator of the anti-inflammatory actions of therapeutic glucocorticoids (GCs) in vivo. In this study we delineate the role of 11β-HSD1 in the effects of GC on bone during inflammatory polyarthritis. Its function was assessed in bone biopsies from patients with RA and osteoarthritis, and in primary osteoblasts and osteoclasts. Bone metabolism was assessed in the TNF-tg model of polyarthritis treated with oral GC (corticosterone), in animals with global (TNF-tg11βKO), mesenchymal (including osteoblast) (TNF-tg11βflx/tw2cre) and myeloid (including osteoclast) (TNF-tg11βflx/LysMcre) deletion. Bone parameters were assessed by micro-CT, static histomorphometry and serum metabolism markers. We observed a marked increase in 11β-HSD1 activity in bone in RA relative to osteoarthritis bone, whilst the pro-inflammatory cytokine TNFα upregulated 11β-HSD1 within osteoblasts and osteoclasts. In osteoclasts, 11β-HSD1 mediated the suppression of bone resorption by GCs. Whilst corticosterone prevented the inflammatory loss of trabecular bone in TNF-tg animals, counterparts with global deletion of 11β-HSD1 were resistant to these protective actions, characterised by increased osteoclastic bone resorption. Targeted deletion of 11β-HSD1 within osteoclasts and myeloid derived cells partially reproduced the GC resistant phenotype. These data reveal the critical role of 11β-HSD1 within bone and osteoclasts in mediating the suppression of inflammatory bone loss in response to therapeutic GCs in chronic inflammatory disease.

Effect of AZD4017, a Selective 11β-HSD1 Inhibitor, on Bone Turnover Markers in Postmenopausal Osteopenia

CONTEXT

The causative link between circulating glucocorticoid excess and osteoporosis is well-established. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which increases local cortisol production, is expressed in human osteoblasts and its activity increases with age.

OBJECTIVE

We hypothesized that local 11β-HSD1 might mediate an age-related decrease in bone formation and that selective 11β-HSD1 inhibition may enhance bone formation.

METHODS

A dual-center, phase II, randomized, double-blind, placebo-controlled trial of 90 days' treatment with AZD4017 (a selective 11β-HSD1 inhibitor) was conducted in 55 postmenopausal women with osteopenia. Participants received 400 mg oral AZD4017 twice daily vs matched placebo over 90 days. The primary outcome measure was the impact on the bone formation marker osteocalcin. Secondary objectives included correlation with 11β-HSD1 activity.

RESULTS

At 90 days, osteocalcin levels did not differ between treatment groups: active (mean 22.3 [SD 8.6] ng/mL, n = 22) and placebo (21.7 [SD 9.2] ng/mL, n = 24), with a baseline-adjusted treatment effect of 0.95 (95% CI: -2.69, 4.60). The results from the urinary [THF + alloTHF]/THE ratio (index of 11β-HSD1 activity) and the urinary cortisol/cortisone ratio (index of 11β-HSD2 activity) confirmed a > 90% inhibition of 11β-HSD1 but no change in activity of 11β-HSD2.

CONCLUSION

This trial demonstrates that AZD4017 selectively inhibits 11β-HSD1 activity in vivo in a safe and reversible manner. Following 90 days of treatment, there is no effect on bone formation, indicating that the relative impairment of bone mineral density in postmenopausal women is not mediated by local intracellular production of cortisol under normal physiological concentrations.

Controlled dual release of dihydrotestosterone and flutamide from polycaprolactone electrospun scaffolds accelerate burn wound healing

Wound healing is a complex process involving multiple independent and overlapping sequential physiological mechanisms. In addition to cutaneous injury, a severe burn stimulates physiological derangements that induce a systemic hypermetabolic response resulting in impaired wound healing. Topical application of the anti‐androgen drug, flutamide accelerates cutaneous wound healing, whereas paradoxically systemic dihydrotestosterone (DHT) improves burn wound healing. We developed and characterized a PCL scaffold that is capable of controlled release of androgen (DHT) and anti‐androgen (F) individually or together. This study aims to investigate whether local modification of androgen actions has an impact on burn injury wound healing. In a full‐thickness burn wound healing, mouse model, DHT/F‐scaffold showed a significantly faster wound healing compared with F‐scaffold or DHT‐scaffold. Histology analysis confirmed that DHT/F‐scaffold exhibited higher re‐epithelization, cell proliferation, angiogenesis, and collagen deposition. Dual release of DHT and F from PCL scaffolds promoted cell proliferation of human keratinocytes and alters the keratinocyte cell cycle. Lastly, no adverse effects on androgen‐dependent organs, spleen and liver were observed. In conclusion, we demonstrated DHT plus F load PCL scaffolds accelerated burn wound healing when loading alone did not. These findings point to a complex role of androgens in burn wound healing and open novel therapeutic avenues for treating severe burn patients.

Inactivation of the CIC-DUX4 oncogene through P300/CBP inhibition, a therapeutic approach for CIC-DUX4 sarcoma

CIC-DUX4 sarcoma (CDS) is a highly aggressive and metastatic small round type of predominantly pediatric sarcoma driven by a fusion oncoprotein comprising the transcriptional repressor Capicua (CIC) fused to the C-terminal transcriptional activation domain of DUX4. CDS rapidly develops resistance to chemotherapy, thus novel specific therapies are greatly needed. We demonstrate that CIC-DUX4 requires P300/CBP to induce histone H3 acetylation, activate its targets, and drive oncogenesis. We describe the synthetic route to a selective and highly potent P300/CBP inhibitor named iP300w and related stereoisomers, and find that iP300w efficiently suppresses CIC-DUX4 transcriptional activity and reverses CIC-DUX4 induced acetylation. iP300w is active at 100-fold lower concentrations than related stereoisomers or A-485. At low doses, iP300w shows specificity to CDS cancer cell lines, rapidly inducing cell cycle arrest and preventing growth of established CDS xenograft tumors when delivered in vivo. The effectiveness of iP300w to inactivate CIC-DUX4 highlights a promising therapeutic opportunity for CDS.

The contradictory role of androgens in cutaneous and major burn wound healing

Wound healing is a complex process involving four overlapping phases: haemostasis, inflammation, cell recruitment and matrix remodeling. In mouse models, surgical, pharmacological and genetic approaches targeting androgen actions in skin have shown that androgens increase interleukin-6 and tumor necrosis factor-α production and reduce wound re-epithelization and matrix deposition, retarding cutaneous wound healing. Similarly, clinical studies have shown that cutaneous wound healing is slower in men compared to women. However, in major burn injury, which triggers not only local wound-healing processes but also systemic hypermetabolism, the role of androgens is poorly understood. Recent studies have claimed that a synthetic androgen, oxandrolone, increases protein synthesis, improves lean body mass and shortens length of hospital stay. However, the possible mechanisms by which oxandrolone regulates major burn injury have not been reported. In this review, we summarize the current findings on the roles of androgens in cutaneous and major burn wound healing, as well as androgens as a potential therapeutic treatment option for patients with major burn injuries.

Endogenous Glucocorticoid Metabolism in Bone: Friend or Foe

The role of tissue specific metabolism of endogenous glucocorticoids (GCs) in the pathogenesis of human disease has been a field of intense interest over the last 20 years, fuelling clinical trials of metabolism inhibitors in the treatment of an array of metabolic diseases. Localised pre-receptor metabolism of endogenous and therapeutic GCs by the 11β-hydroxysteroid dehydrogenase (11β-HSD) enzymes (which interconvert endogenous GCs between their inactive and active forms) are increasingly recognised as being critical in mediating both their positive and negative actions on bone homeostasis. In this review we explore the roles of endogenous and therapeutic GC metabolism by the 11β-HSD enzymes in the context of bone metabolism and bone cell function, and consider future strategies aimed at modulating this system in order to manage and treat various bone diseases.

Cumulative dispensing of high oral corticosteroid doses for treating asthma in Australia

OBJECTIVE

To estimate the level of dispensing of oral corticosteroids (OCS) for managing asthma in Australia, with a particular focus on the cumulative dispensing of doses associated with long term toxicity (≥ 1000 mg prednisolone-equivalent).

DESIGN

Retrospective cohort study; analysis of 10% random sample of Pharmaceutical Benefits Scheme (PBS) dispensing data.

PARTICIPANTS, SETTING

People aged 12 years or more treated for asthma during 2014-2018, according to dispensing of controller inhaled corticosteroids (ICS).

MAIN OUTCOME MEASURES

Number of people dispensed OCS for managing asthma during 2014-2018; proportion who were cumulatively dispensed at least 1000 mg prednisolone-equivalent. The secondary outcome was the number of people dispensed at least 1000 mg prednisolone-equivalent during 2018, stratified by inhaler controller dose and use.

RESULTS

124 011 people had been dispensed at least two prescriptions of ICS during 2014-2018 and met the study definition for asthma, of whom 64 112 (51.7%) had also been dispensed OCS, including 34 580 (27.9% of the asthma group) cumulatively dispensed 1000 mg prednisolone-equivalent or more. Of 138 073 people dispensed OCS at this level, 68 077 (49%) were patients with airway diseases. Dispensing of diabetes and osteoporosis medications was more common for people cumulatively dispensed 1000 mg prednisolone-equivalent or more. During 2018, 4633 people with asthma using high dose ICS controllers were dispensed 1000 mg prednisolone-equivalent or more, for 2316 of whom (50%) controller use was inadequate.

CONCLUSIONS

Cumulative exposure to OCS in Australia reaches levels associated with toxicity in one-quarter of patients with asthma using ICS. Cumulative dispensing of potentially toxic OCS amounts often accompanies inadequate inhaler controller dispensing. Better approaches are needed to improve adherence to controller therapy, improve outcomes for people with asthma, and to minimise the use and toxicity of OCS.

Dihydrotestosterone (DHT) Enhances Wound Healing of Major Burn Injury by Accelerating Resolution of Inflammation in Mice

Androgens have been known to inhibit cutaneous wound healing in men and male mice. However, in children with major burn injuries, a synthetic androgen was reported clinically to improve wound healing. The aim of this study is to investigate the role of dihydrotestosterone (DHT) as a new therapeutic approach in treating major burn injury. In the present study, mice received systemic androgen treatment post major burn injury. Wound healing rate and body weight were monitored over 21 days. The serum level of inflammatory cytokines/chemokines were measured using multiplex immunoassays. In addition, splenocyte enumeration was performed by flow cytometry. Healing phases of inflammation, re-epithelialization, cell proliferation and collagen deposition were also examined. In results, DHT treated mice lost less weight and displayed accelerated wound healing but has no impact on hypermetabolism. Mice, after burn injury, displayed acute systemic inflammatory responses over 21 days. DHT treatment shortened the systemic inflammatory response with reduced splenic weight and monocyte numbers on day 14 and 21. DHT treatment also reduced wound infiltrating macrophage numbers. In conclusion, DHT treatment facilitates local wound healing by accelerating the resolution of inflammation, but not through alterations of post-burn hypermetabolic response.

Therapeutic glucocorticoids: mechanisms of actions in rheumatic diseases

Therapeutic glucocorticoids have been widely used in rheumatic diseases since they became available over 60 years ago. Despite the advent of more specific biologic therapies, a notable proportion of individuals with chronic rheumatic diseases continue to be treated with these drugs. Glucocorticoids are powerful, broad-spectrum anti-inflammatory agents, but their use is complicated by an equally broad range of adverse effects. The specific cellular mechanisms by which glucocorticoids have their therapeutic action have been difficult to identify, and attempts to develop more selective drugs on the basis of the action of glucocorticoids have proven difficult. The actions of glucocorticoids seem to be highly cell-type and context dependent. Despite emerging data on the effect of tissue-specific manipulation of glucocorticoid receptors in mouse models of inflammation, the cell types and intracellular targets of glucocorticoids in rheumatic diseases have not been fully identified. Although showing some signs of decline, the use of systemic glucocorticoids in rheumatology is likely to continue to be widespread, and careful consideration is required by rheumatologists to balance the beneficial effects and deleterious effects of these agents.

Vitamin D to Prevent Lung Injury Following Esophagectomy-A Randomized, Placebo-Controlled Trial

OBJECTIVES

Observational studies suggest an association between vitamin D deficiency and adverse outcomes of critical illness and identify it as a potential risk factor for the development of lung injury. To determine whether preoperative administration of oral high-dose cholecalciferol ameliorates early acute lung injury postoperatively in adults undergoing elective esophagectomy.

DESIGN

A double-blind, randomized, placebo-controlled trial.

SETTING

Three large U.K. university hospitals.

PATIENTS

Seventy-nine adult patients undergoing elective esophagectomy were randomized.

INTERVENTIONS

A single oral preoperative (3-14 d) dose of 7.5 mg (300,000 IU; 15 mL) cholecalciferol or matched placebo.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was change in extravascular lung water index at the end of esophagectomy. Secondary outcomes included PaO2:FIO2 ratio, development of lung injury, ventilator and organ-failure free days, 28 and 90 day survival, safety of cholecalciferol supplementation, plasma vitamin D status (25(OH)D, 1,25(OH)2D, and vitamin D-binding protein), pulmonary vascular permeability index, and extravascular lung water index day 1 postoperatively. An exploratory study measured biomarkers of alveolar-capillary inflammation and injury. Forty patients were randomized to cholecalciferol and 39 to placebo. There was no significant change in extravascular lung water index at the end of the operation between treatment groups (placebo median 1.0 [interquartile range, 0.4-1.8] vs cholecalciferol median 0.4 mL/kg [interquartile range, 0.4-1.2 mL/kg]; p = 0.059). Median pulmonary vascular permeability index values were significantly lower in the cholecalciferol treatment group (placebo 0.4 [interquartile range, 0-0.7] vs cholecalciferol 0.1 [interquartile range, -0.15 to -0.35]; p = 0.027). Cholecalciferol treatment effectively increased 25(OH)D concentrations, but surgery resulted in a decrease in 25(OH)D concentrations at day 3 in both arms. There was no difference in clinical outcomes.

CONCLUSIONS

High-dose preoperative treatment with oral cholecalciferol was effective at increasing 25(OH)D concentrations and reduced changes in postoperative pulmonary vascular permeability index, but not extravascular lung water index.

Glucocorticoids and Bone: Consequences of Endogenous and Exogenous Excess and Replacement Therapy

Osteoporosis associated with long-term glucocorticoid therapy remains a common and serious bone disease. Additionally, in recent years it has become clear that more subtle states of endogenous glucocorticoid excess may have a major impact on bone health. Adverse effects can be seen with mild systemic glucocorticoid excess, but there is also evidence of tissue-specific regulation of glucocorticoid action within bone as a mechanism of disease. This review article examines (1) the role of endogenous glucocorticoids in normal bone physiology, (2) the skeletal effects of endogenous glucocorticoid excess in the context of endocrine conditions such as Cushing disease/syndrome and autonomous cortisol secretion (subclinical Cushing syndrome), and (3) the actions of therapeutic (exogenous) glucocorticoids on bone. We review the extent to which the effect of glucocorticoids on bone is influenced by variations in tissue metabolizing enzymes and glucocorticoid receptor expression and sensitivity. We consider how the effects of therapeutic glucocorticoids on bone are complicated by the effects of the underlying inflammatory disease being treated. We also examine the impact that glucocorticoid replacement regimens have on bone in the context of primary and secondary adrenal insufficiency. We conclude that even subtle excess of endogenous or moderate doses of therapeutic glucocorticoids are detrimental to bone. However, in patients with inflammatory disorders there is a complex interplay between glucocorticoid treatment and underlying inflammation, with the underlying condition frequently representing the major component underpinning bone damage.

Glucocorticoids and Bone: Consequences of Endogenous and Exogenous Excess and Replacement Therapy

Osteoporosis associated with long-term glucocorticoid therapy remains a common and serious bone disease. Additionally, in recent years it has become clear that more subtle states of endogenous glucocorticoid excess may have a major impact on bone health. Adverse effects can be seen with mild systemic glucocorticoid excess, but there is also evidence of tissue-specific regulation of glucocorticoid action within bone as a mechanism of disease. This review article examines (1) the role of endogenous glucocorticoids in normal bone physiology, (2) the skeletal effects of endogenous glucocorticoid excess in the context of endocrine conditions such as Cushing disease/syndrome and autonomous cortisol secretion (subclinical Cushing syndrome), and (3) the actions of therapeutic (exogenous) glucocorticoids on bone. We review the extent to which the effect of glucocorticoids on bone is influenced by variations in tissue metabolizing enzymes and glucocorticoid receptor expression and sensitivity. We consider how the effects of therapeutic glucocorticoids on bone are complicated by the effects of the underlying inflammatory disease being treated. We also examine the impact that glucocorticoid replacement regimens have on bone in the context of primary and secondary adrenal insufficiency. We conclude that even subtle excess of endogenous or moderate doses of therapeutic glucocorticoids are detrimental to bone. However, in patients with inflammatory disorders there is a complex interplay between glucocorticoid treatment and underlying inflammation, with the underlying condition frequently representing the major component underpinning bone damage.

11 Beta-hydroxysteroid dehydrogenase type 1 regulates synovitis, joint destruction, and systemic bone loss in chronic polyarthritis

OBJECTIVE

In rheumatoid arthritis, the enzyme 11 beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is highly expressed at sites of inflammation, where it converts inactive glucocorticoids (GC) to their active counterparts. In conditions of GC excess it has been shown to be a critical regulator of muscle wasting and bone loss. Here we examine the contribution of 11β-HSD1 to the pathology of persistent chronic inflammatory disease.

METHODS

To determine the contribution of 11β-HSD1 to joint inflammation, destruction and systemic bone loss associated with persistent inflammatory arthritis, we generated mice with global and mesenchymal specific 11β-HSD1 deletions in the TNF-transgenic (TNF-tg) model of chronic polyarthritis. Disease severity was determined by clinical scoring. Histology was assessed in formalin fixed sections and fluorescence-activated cell sorting (FACS) analysis of synovial tissue was performed. Local and systemic bone loss were measured by micro computed tomography (micro-CT). Measures of inflammation and bone metabolism were assessed in serum and in tibia mRNA.

RESULTS

Global deletion of 11β-HSD1 drove an enhanced inflammatory phenotype, characterised by florid synovitis, joint destruction and systemic bone loss. This was associated with increased pannus invasion into subchondral bone, a marked polarisation towards pro-inflammatory M1 macrophages at sites of inflammation and increased osteoclast numbers. Targeted mesenchymal deletion of 11β-HSD1 failed to recapitulate this phenotype suggesting that 11β-HSD1 within leukocytes mediate its protective actions in vivo.

CONCLUSIONS

We demonstrate a fundamental role for 11β-HSD1 in the suppression of synovitis, joint destruction, and systemic bone loss. Whilst a role for 11β-HSD1 inhibitors has been proposed for metabolic complications in inflammatory diseases, our study suggests that this approach would greatly exacerbate disease severity.

Comparison of blood sampling methods for plasma corticosterone measurements in mice associated with minimal stress-related artefacts

Accurate measurement of circulating glucocorticoid concentrations in rodents is often hampered by the stress-related activation of the hypothalamic-pituitaryadrenal axis during animal handling. The present study aims to identify methods of blood collection associated with minimal stress and thus artificial increases in plasma glucocorticoid levels. Using two strains of mice, we evaluated common laboratory methods of non-terminal (tail blood sampling with or without restraint; retro-orbital puncture) and terminal blood collection (cardiac puncture) and their immediate and prolonged effect on plasma corticosterone levels. Compared to retro-orbital and cardiac puncture, mice from both the unrestrained and restrained tail snip collection groups displayed the lowest plasma corticosterone levels in both mouse strains. Plasma corticosterone levels in samples obtained from retro-orbital and cardiac puncture collection were up to twenty times higher than those measured in mice undergoing blood collection via tail snip. Repeat tail snip collections (every 30 min for 120 min, or once after 120 min) revealed sustained hypercortisolaemia, compared to the initial collection. We conclude that blood sampling via tail snip without restraint remains the gold-standard method of collection that is associated with minimal stress-related artefacts and hence feasible for single time point corticosterone analyses.

Correction to: Guidelines for the diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI) in critically ill patients (Part I): Society of Critical Care Medicine (SCCM) and European Society of Intensive Care Medicine (ESICM) 2017

To update the 2008 consensus statements for the diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI) in adult and pediatric patients.

Role of 11β-HSD type 1 in abnormal HPA axis activity during immune-mediated arthritis

Patients with chronic immune-mediated arthritis exhibit abnormal hypothalamo-pituitary-adrenal (HPA) axis activity. The basis for this abnormality is not known. Immune-mediated arthritis is associated with increased extra-adrenal synthesis of active glucocorticoids by the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. 11β-HSD1 is expressed in the central nervous system, including regions involved in HPA axis regulation. We examined whether altered 11β-HSD1 expression within these regions contributes to HPA axis dysregulation during arthritis. The expression of 11β-HSD1, and other components of glucocorticoid signaling, were examined in various brain regions and the pituitary gland of mice with experimentally induced arthritis. Two arthritis protocols were employed: The K/BxN spontaneous arthritis model for chronic arthritis and the K/BxN serum transfer arthritis model for acute arthritis. 11β-HSD1 mRNA (Hsd11b1) was expressed in the hippocampus, hypothalamus, cortex, cerebellum and pituitary gland. Hypothalamic Hsd11b1 expression did not change in response to arthritis in either model. Pituitary Hsd11b1 expression was however significantly increased in both chronic and acute arthritis models. Hippocampal Hsd11b1 was decreased in acute but not chronic arthritis. Chronic, but not acute, arthritis was associated with a reduction in hypothalamic corticotropin-releasing hormone and arginine vasopressin expression. In both models, serum adrenocorticotropic hormone and corticosterone levels were no different from non-inflammatory controls. These findings demonstrate inflammation-dependent regulation of Hsd11b1 expression in the pituitary gland and hippocampus. The upregulation of 11β-HSD1 expression in the pituitary during both chronic and acute arthritis, and thus, an increase in glucocorticoid negative feedback, could contribute to the abnormalities in HPA axis activity seen in immune-mediated arthritis.

Guidelines for the diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI) in critically ill patients (Part I): Society of Critical Care Medicine (SCCM) and European Society of Intensive Care Medicine (ESICM) 2017

OBJECTIVE

To update the 2008 consensus statements for the diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI) in adult and pediatric patients.

PARTICIPANTS

A multispecialty task force of 16 international experts in Critical Care Medicine, endocrinology, and guideline methods, all of them members of the Society of Critical Care Medicine and/or the European Society of Intensive Care Medicine.

DESIGN/METHODS

The recommendations were based on the summarized evidence from the 2008 document in addition to more recent findings from an updated systematic review of relevant studies from 2008 to 2017 and were formulated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. The strength of each recommendation was classified as strong or conditional, and the quality of evidence was rated from high to very low based on factors including the individual study design, the risk of bias, the consistency of the results, and the directness and precision of the evidence. Recommendation approval required the agreement of at least 80% of the task force members.

RESULTS

The task force was unable to reach agreement on a single test that can reliably diagnose CIRCI, although delta cortisol (change in baseline cortisol at 60 min of <9 µg/dl) after cosyntropin (250 µg) administration and a random plasma cortisol of <10 µg/dl may be used by clinicians. We suggest against using plasma free cortisol or salivary cortisol level over plasma total cortisol (conditional, very low quality of evidence). For treatment of specific conditions, we suggest using intravenous (IV) hydrocortisone <400 mg/day for ≥3 days at full dose in patients with septic shock that is not responsive to fluid and moderate- to high-dose vasopressor therapy (conditional, low quality of evidence). We suggest not using corticosteroids in adult patients with sepsis without shock (conditional recommendation, moderate quality of evidence). We suggest the use of IV methylprednisolone 1 mg/kg/day in patients with early moderate to severe acute respiratory distress syndrome (PaO₂/FiO₂ < 200 and within 14 days of onset) (conditional, moderate quality of evidence). Corticosteroids are not suggested for patients with major trauma (conditional, low quality of evidence).

CONCLUSIONS

Evidence-based recommendations for the use of corticosteroids in critically ill patients with sepsis and septic shock, acute respiratory distress syndrome, and major trauma have been developed by a multispecialty task force.

Endogenous glucocorticoid signaling in chondrocytes attenuates joint inflammation and damage

Previous studies demonstrated that endogenous glucocorticoid signaling in osteoblasts promotes inflammation in murine immune arthritis. The current study determined whether disruption of endogenous glucocorticoid signaling in chondrocytes also modulates the course and severity of arthritis. Tamoxifen-inducible chondrocyte-targeted glucocorticoid receptor-knockout (chGRKO) mice were generated by breeding GR^flox/flox mice with tamoxifen-inducible collagen 2a1 Cre (Col2a1-CreER^T2) mice. Antigen-induced arthritis (AIA) and K/BxN serum transfer-induced arthritis (STIA) were induced in both chGRKO mice and their Cre-negative GR^flox/flox littermates [wild type (WT)]. Arthritis was assessed by measurement of joint swelling and histology of joints collected at d 14. Neutrophil activity and gene expression patterns associated with cartilage damage were also evaluated. In both arthritis models clinical (joint swelling) and histologic indices of inflammatory activity were significantly greater in chGRKO than in WT mice. The STIA model was characterized by early up-regulation of CXCR2/CXCR2 ligand gene expression in ankle tissues, and significant and selective expansion of splenic CXCR2⁺ neutrophils in chGRKO arthritic compared to WT arthritic mice. At later stages, gene expression of enzymes involved in cartilage degradation was up-regulated in chGRKO but not WT arthritic mice. Therefore, we summarize that chondrocytes actively mitigate local joint inflammation, cartilage degradation and systemic neutrophil activity via a glucocorticoid-dependent pathway.-Tu, J., Stoner, S., Fromm, P. D., Wang, T., Chen, D., Tuckermann, J., Cooper, M. S., Seibel, M. J., Zhou, H. Endogenous glucocorticoid signaling in chondrocytes attenuates joint inflammation and damage.

Successful Asfotase Alfa Treatment in an Adult Dialysis Patient With Childhood-Onset Hypophosphatasia

Hypophosphatasia is an inherited disease characterized by reduced alkaline phosphatase activity, extracellular accumulation of inorganic pyrophosphate, and impaired bone mineralization. Asfotase alfa (AA) is a recombinant human alkaline phosphatase therapy approved for treatment of pediatric-onset hypophosphatasia. Studies show promising outcome in AA-treated children with hypophosphatasia; however, data on adults with pediatric-onset hypophosphatasia are scarce. We report on a 59-year-old woman with childhood-onset hypophosphatasia and a history of multiple fractures and orthopedic procedures. Owing to renal failure (histological diagnosis: focal segmental glomerulosclerosis), hemodialysis was started in 2013. By the end of 2015, the patient was unable to walk, could only stand for 30 seconds, and was completely dependent on help for activities of daily living. After 13 months of AA therapy, the patient showed a dramatic increase in quality of life (increased mobility), reduction in pain medication, and a significant improvement in bone mineralization throughout the skeleton, including consolidation of existing fractures and no occurrence of new fractures. This case report demonstrates a relevant therapeutic success of AA treatment in an adult hemodialysis patient with childhood onset of hypophosphatasia.

11β-Hydroxysteroid dehydrogenase type 1 within muscle protects against the adverse effects of local inflammation

Muscle wasting is a common feature of inflammatory myopathies. Glucocorticoids (GCs), although effective at suppressing inflammation and inflammatory muscle loss, also cause myopathy with prolonged administration. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a bidirectional GC-activating enzyme that is potently upregulated by inflammation within mesenchymal-derived tissues. We assessed the regulation of this enzyme with inflammation in muscle, and examined its functional impact on muscle. The expression of 11β-HSD1 in response to proinflammatory stimuli was determined in a transgenic murine model of chronic inflammation (TNF-Tg) driven by overexpression of tumour necrosis factor (TNF)-α within tissues, including muscle. The inflammatory regulation and functional consequences of 11β-HSD1 expression were examined in primary cultures of human and murine myotubes and human and murine muscle biopsies ex vivo. The contributions of 11β-HSD1 to muscle inflammation and wasting were assessed in vivo with the TNF-Tg mouse on an 11β-HSD1 null background. 11β-HSD1 was significantly upregulated within the tibialis anterior and quadriceps muscles from TNF-Tg mice. In human and murine primary myotubes, 11β-HSD1 expression and activity were significantly increased in response to the proinflammatory cytokine TNF-α (mRNA, 7.6-fold, p < 0.005; activity, 4.1-fold, p < 0.005). Physiologically relevant levels of endogenous GCs activated by 11β-HSD1 suppressed proinflammatory cytokine output (interkeukin-6, TNF-α, and interferon-γ), but had little impact on markers of muscle wasting in human myotube cultures. TNF-Tg mice on an 11β-11β-HSD1 knockout background developed greater muscle wasting than their TNF-Tg counterparts (27.4% less; p < 0.005), with smaller compacted muscle fibres and increased proinflammatory gene expression relative to TNF-Tg mice with normal 11β-HSD1 activity. This study demonstrates that inflammatory stimuli upregulate 11β-HSD1 expression and GC activation within muscle. Although concerns have been raised that excess levels of GCs may be detrimental to muscle, in this inflammatory TNF-α-driven model, local endogenous GC activation appears to be an important anti-inflammatory response that protects against inflammatory muscle wasting in vivo. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Reduction in daily hydrocortisone dose improves bone health in primary adrenal insufficiency

OBJECTIVE

Individuals with primary adrenal insufficiency (PAI) or congenital adrenal hyperplasia (CAH) receive life-long glucocorticoid (GC) replacement therapy. Current daily GC doses are still higher than the reported adrenal cortisol production rate. This GC excess could result in long-term morbidities such as osteoporosis. No prospective trials have investigated the long-term effect of GC dose changes in PAI and CAH patients.

METHODS

This is a prospective and longitudinal study including 57 subjects with PAI (42 women) and 33 with CAH (21 women). Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry at baseline and after 2 years. Subjects were divided into three groups (similar baseline characteristics) depending on changes in daily hydrocortisone equivalent dose (group 1: unchanged 25.2±8.2  mg (mean±S.D., n=50); group 2: increased 18.7±10.3 to 25.9±12.0  mg (n=13); group 3: decreased 30.8±8.5 to 21.4±7.2  mg (n=27)).

RESULTS

Subjects in group 1 showed normal lumbar and femoral Z-scores which were unchanged over time. Group 2 subjects showed a significant decrease in femoral neck Z-scores over time (-0.15±1.1 to -0.37±1.0 (P<0.05)), whereas group 3 subjects showed a significant increase in lumbar spine and hip Z-scores (L1-L4: -0.93±1.2 to -0.65±1.5 (P<0.05); total hip: -0.40±1.0 to -0.28±1.0 (P<0.05)). No changes in BMI over time were seen within any group. Reduction in GC dose did not increase the risk of adrenal crisis.

CONCLUSION

This study demonstrates for the first time that cautious reduction in hydrocortisone equivalent doses leads to increases in BMD, whereas dose increments reduced BMD. These data emphasize the need for the lowest possible GC replacement dose in AI patients to maintain health and avoid long-term adverse effects.

Glucocorticoids, bone and energy metabolism

Prolonged exposure to excessive levels of endogenous or exogenous glucocorticoids is associated with serious clinical features including altered body composition and the development of insulin resistance, impaired glucose tolerance and diabetes. It had been assumed that these adverse effects were mediated by direct effects of glucocorticoids on tissues such as adipose or liver. Recent studies have however indicated that these effects are, at least in part, mediated through the actions of glucocorticoids on bone and specifically the osteoblast. In mice, targeted abrogation of glucocorticoid signalling in osteoblasts significantly attenuated the changes in body composition and systemic fuel metabolism seen during glucocorticoid treatment. Heterotopic expression of osteocalcin in the liver of normal mice was also able to protect against the metabolic changes induced by glucocorticoids indicating that osteocalcin was the likely factor connecting bone osteoblasts to systemic fuel metabolism. Studies are now needed in humans to determine the extent to which glucocorticoid induced changes in body composition and systemic fuel metabolism are mediated through bone. This article is part of a Special Issue entitled Bone and diabetes.

Differential glucocorticoid metabolism in patients with persistent versus resolving inflammatory arthritis

Introduction

Impairment in the ability of the inflamed synovium to generate cortisol has been proposed to be a factor in the persistence and severity of inflammatory arthritis. In the inflamed synovium, cortisol is generated from cortisone by the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. The objective of this study was to determine the role of endogenous glucocorticoid metabolism in the development of persistent inflammatory arthritis.

Methods

Urine samples were collected from patients with early arthritis (symptoms ≤12 weeks duration) whose final diagnostic outcomes were established after clinical follow-up and from patients with established rheumatoid arthritis (RA). All patients were free of disease-modifying anti-rheumatic drugs at the time of sample collection. Systemic measures of glucocorticoid metabolism were assessed in the urine samples by gas chromatography/mass spectrometry. Clinical data including CRP and ESR were also collected at baseline.

Results

Systemic measures of 11β-HSD1 activity were significantly higher in patients with early arthritis whose disease went on to persist, and also in the subgroup of patients with persistent disease who developed RA, when compared with patients whose synovitis resolved over time. We observed a significant positive correlation between systemic 11β-HSD1 activity and ESR/CRP in patients with established RA but not in any of the early arthritis patients group.

Conclusions

The present study demonstrates that patients with a new onset of synovitis whose disease subsequently resolved had significantly lower levels of systemic 11β-HSD1 activity when compared with patients whose synovitis developed into RA or other forms of persistent arthritis. Low absolute levels of 11β-HSD1 activity do not therefore appear to be a major contributor to the development of RA and it is possible that a high total body 11β-HSD1 activity during early arthritis may reduce the probability of disease resolution.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0633-2) contains supplementary material, which is available to authorized users.

Vitamin D deficiency contributes directly to the acute respiratory distress syndrome (ARDS)

Rationale

Vitamin D deficiency has been implicated as a pathogenic factor in sepsis and intensive therapy unit mortality but has not been assessed as a risk factor for acute respiratory distress syndrome (ARDS). Causality of these associations has never been demonstrated.

Objectives

To determine if ARDS is associated with vitamin D deficiency in a clinical setting and to determine if vitamin D deficiency in experimental models of ARDS influences its severity.

Methods

Human, murine and in vitro primary alveolar epithelial cell work were included in this study.

Findings

Vitamin D deficiency (plasma 25(OH)D levels <50 nmol/L) was ubiquitous in patients with ARDS and present in the vast majority of patients at risk of developing ARDS following oesophagectomy. In a murine model of intratracheal lipopolysaccharide challenge, dietary-induced vitamin D deficiency resulted in exaggerated alveolar inflammation, epithelial damage and hypoxia. In vitro, vitamin D has trophic effects on primary human alveolar epithelial cells affecting >600 genes. In a clinical setting, pharmacological repletion of vitamin D prior to oesophagectomy reduced the observed changes of in vivo measurements of alveolar capillary damage seen in deficient patients.

Conclusions

Vitamin D deficiency is common in people who develop ARDS. This deficiency of vitamin D appears to contribute to the development of the condition, and approaches to correct vitamin D deficiency in patients at risk of ARDS should be developed.

Trial registration

UKCRN ID 11994.

Disruption of glucocorticoid signaling in chondrocytes delays metaphyseal fracture healing but does not affect normal cartilage and bone development

States of glucocorticoid excess are associated with defects in chondrocyte function. Most prominently there is a reduction in linear growth but delayed healing of fractures that require endochondral ossification to also occur. In contrast, little is known about the role of endogenous glucocorticoids in chondrocyte function. As glucocorticoids exert their cellular actions through the glucocorticoid receptor (GR), we aimed to elucidate the role of endogenous glucocorticoids in chondrocyte function in vivo through characterization of tamoxifen-inducible chondrocyte-specific GR knockout (chGRKO) mice in which the GR was deleted at various post-natal ages. Knee joint architecture, cartilage structure, growth plates, intervertebral discs, long bone length and bone micro-architecture were similar in chGRKO and control mice at all ages. Analysis of fracture healing in chGRKO and control mice demonstrated that in metaphyseal fractures, chGRKO mice formed a larger cartilaginous callus at 1 and 2 week post-surgery, as well as a smaller amount of well-mineralized bony callus at the fracture site 4 week post-surgery, when compared to control mice. In contrast, chondrocyte-specific GR knockout did not affect diaphyseal fracture healing. We conclude that endogenous GC signaling in chondrocytes plays an important role during metaphyseal fracture healing but is not essential for normal long bone growth.

PET and SPECT imaging of a radiolabeled minigastrin analogue conjugated with DOTA, NOTA, and NODAGA and labeled with (64)Cu, (68)Ga, and (111)In

Cholecystokinin-2 (CCK-2) receptors, overexpressed in cancer types such as small cell lung cancers (SCLC) and medullary thyroid carcinomas (MTC), may serve as targets for peptide receptor radionuclide imaging. A variety of CCK and gastrin analogues has been developed, but a major drawback is metabolic instability or high kidney uptake. The minigastrin analogue PP-F11 has previously been shown to be a promising peptide for imaging of CCK-2 receptor positive tumors and was therefore further evaluated. The peptide was conjugated with one of the macrocyclic chelators DOTA, NOTA, or NODAGA. The peptide conjugates were then radiolabeled with either (68)Ga, (64)Cu, or (111)In. All (radio)labeled compounds were evaluated in vitro (IC50) and in vivo (biodistribution and PET/CT and SPECT/CT imaging). IC50 values were in the low nanomolar range for all compounds (0.79-1.51 nM). In the biodistribution studies, (68)Ga- and (111)In-labeled peptides showed higher tumor-to-background ratios than the (64)Cu-labeled compounds. All tested radiolabeled compounds clearly visualized the CCK2 receptor positive tumor in PET or SPECT imaging. The chelator did not seem to affect in vivo behavior of the peptide for (111)In- and (68)Ga-labeled peptides. In contrast, the biodistribution of the (64)Cu-labeled peptides showed high uptake in the liver and in other organs, most likely caused by high blood levels, probably due to dissociation of (64)Cu from the chelator and subsequent transchelation to proteins. Based on the present study, (68)Ga-DOTA-PP-F11 might be a promising radiopharmaceutical for PET/CT imaging of CCK2 receptor expressing tumors such as MTC and SCLC. Clinical studies are warranted to investigate the potential of this tracer.

TNFα-mediated Hsd11b1 binding of NF-κB p65 is associated with suppression of 11β-HSD1 in muscle

The activity of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which converts inactive cortisone (11-dehydrocorticosterone (11-DHC)) (in mice) into the active glucocorticoid (GC) cortisol (corticosterone in mice), can amplify tissue GC exposure. Elevated TNFα is a common feature in a range of inflammatory disorders and is detrimental to muscle function in diseases such as rheumatoid arthritis and chronic obstructive pulmonary disease. We have previously demonstrated that 11β-HSD1 activity is increased in the mesenchymal stromal cells (MSCs) by TNFα treatment and suggested that this is an autoregulatory anti-inflammatory mechanism. This upregulation was mediated by the P2 promoter of the Hsd11b1 gene and was dependent on the NF-κB signalling pathway. In this study, we show that in contrast to MSCs, in differentiated C2C12 and primary murine myotubes, TNFα suppresses Hsd11b1 mRNA expression and activity through the utilization of the alternative P1 promoter. As with MSCs, in response to TNFα treatment, NF-κB p65 was translocated to the nucleus. However, ChIP analysis demonstrated that the direct binding was seen at position -218 to -245 bp of the Hsd11b1 gene's P1 promoter but not at the P2 promoter. These studies demonstrate the existence of differential regulation of 11β-HSD1 expression in muscle cells through TNFα/p65 signalling and the P1 promoter, further enhancing our understanding of the role of 11β-HSD1 in the context of inflammatory disease.

Glucocorticoid-induced osteoporosis: mechanisms, management, and future perspectives

Glucocorticoids are widely used for their unsurpassed anti-inflammatory and immunomodulatory effects. However, the therapeutic use of glucocorticoids is almost always limited by substantial adverse outcomes such as osteoporosis, diabetes, and obesity. These unwanted outcomes are a major dilemma for clinicians because improvements in the primary disorder seem to be achievable only by accepting substantial adverse effects that are often difficult to prevent or treat. To understand the pathogenesis of glucocorticoid-induced osteoporosis, it is necessary to consider that the actions of glucocorticoids on bone and mineral metabolism are strongly dose and time dependent. At physiological concentrations, endogenous glucocorticoids are key regulators of mesenchymal cell differentiation and bone development, with additional regulatory roles in renal and intestinal calcium handling. However, at supraphysiological concentrations, glucocorticoids affect the same systems in different and often unfavourable ways. For many years, these anabolic and catabolic actions of glucocorticoids on bone were deemed paradoxical. In this Review, we highlight recent advances in our understanding of the mechanisms underlying the physiology and pathophysiology of glucocorticoid action on the skeleton and discuss present and future management strategies for glucocorticoid-induced osteoporosis.

11β-Hydroxysteroid dehydrogenase 1: translational and therapeutic aspects

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts the inactive glucocorticoid cortisone and its active form cortisol. It is widely expressed and, although bidirectional, in vivo it functions predominantly as an oxoreductase, generating active glucocorticoid. This allows glucocorticoid receptor activation to be regulated at a prereceptor level in a tissue-specific manner. In this review, we will discuss the enzymology and molecular biology of 11β-HSD1 and the molecular basis of cortisone reductase deficiencies. We will also address how altered 11β-HSD1 activity has been implicated in a number of disease states, and we will explore its role in the physiology and pathologies of different tissues. Finally, we will address the current status of selective 11β-HSD1 inhibitors that are in development and being tested in phase II trials for patients with the metabolic syndrome. Although the data are preliminary, therapeutic inhibition of 11β-HSD1 is also an exciting prospect for the treatment of a variety of other disorders such as osteoporosis, glaucoma, intracranial hypertension, and cognitive decline.

Diagnostic evaluation of bone densitometric size adjustment techniques in children with and without low trauma fractures

Several established methods are used to size adjust dual-energy X-ray absorptiometry (DXA) measurements in children. However, there is no consensus as to which method is most diagnostically accurate. All size-adjusted bone mineral density (BMD) values were more diagnostically accurate than non-size-adjusted values. The greatest odds ratio was estimated volumetric BMD for vertebral fracture.

INTRODUCTION

The size dependence of areal bone density (BMDa) complicates the use of DXA in children with abnormal stature. Despite several size adjustment techniques being proposed, there is no consensus as to the most appropriate size adjustment technique for estimating fracture risk in children. The aim of this study was to establish whether size adjustment techniques improve the diagnostic ability of DXA in a cohort of children with chronic diseases.

METHODS

DXA measurements were performed on 450 children, 181 of whom had sustained at least one low trauma fracture. Lumbar spine (L2-L4) and total body less head (TBLH) Z-scores were calculated using different size adjustment techniques, namely BMDa and volumetric BMD for age (bone mineral apparent density (BMAD)); bone mineral content (BMC) and bone area for height; BMC for bone area; BMC for lean mass (adjusted for height); and BMC for bone and body size.

RESULTS

Unadjusted L2-L4 and TBLH BMDa were most sensitive but least specific at distinguishing children with fracture. All size adjustments reduced sensitivity but increased post-test probabilities, from a pre-test probability of 40 % to between 58 and 77 %. The greatest odds ratio for fracture was L2-L4 BMAD for a vertebral fracture and TBLH for lean body mass (LBM) (adjusted for height) for a long bone fracture with diagnostic odds ratios of 9.3 (5.8-14.9) and 6.5 (4.1-10.2), respectively.

CONCLUSION

All size adjustment techniques improved the predictive ability of DXA. The most accurate method for assessing vertebral fracture was BMAD for age. The most accurate method for assessing long bone fracture was TBLH for LBM adjusted for height.

Endogenous Glucocorticoids and Bone

While the adverse effects of glucocorticoids on bone are well described, positive effects of glucocorticoids on the differentiation of osteoblasts are also observed. These paradoxical effects of glucocorticoids are dose dependent. At both physiologicaland supraphysiological levels of glucocorticoids, osteoblasts and osteocytes are the major glucocorticoid target cells. However, the response of the osteoblasts to each of these is quite distinct. At physiology levels, glucocorticoids direct mesenchymal progenitor cells to differentiate towards osteoblasts and thus increase bone formation in a positive way. In contrast with ageing, the excess production of glucocorticoids, at both systemic and intracellular levels, appear to impact on osteoblast and osteocytes in a negative way in a similar fashion to that seen with therapeutic glucocorticoids. This review will focus on therole of glucocorticoids in normal bone physiology, with particular emphasis on the mechanism by which endogenous glucocorticoids impact on bone and its constituent cells.

11β-Hydroxysteroid dehydrogenase blockade prevents age-induced skin structure and function defects

Glucocorticoid (GC) excess adversely affects skin integrity, inducing thinning and impaired wound healing. Aged skin, particularly that which has been photo-exposed, shares a similar phenotype. Previously, we demonstrated age-induced expression of the GC-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in cultured human dermal fibroblasts (HDFs). Here, we determined 11β-HSD1 levels in human skin biopsies from young and older volunteers and examined the aged 11β-HSD1 KO mouse skin phenotype. 11β-HSD1 activity was elevated in aged human and mouse skin and in PE compared with donor-matched photo-protected human biopsies. Age-induced dermal atrophy with deranged collagen structural organization was prevented in 11β-HSD1 KO mice, which also exhibited increased collagen density. We found that treatment of HDFs with physiological concentrations of cortisol inhibited rate-limiting steps in collagen biosynthesis and processing. Furthermore, topical 11β-HSD1 inhibitor treatment accelerated healing of full-thickness mouse dorsal wounds, with improved healing also observed in aged 11β-HSD1 KO mice. These findings suggest that elevated 11β-HSD1 activity in aging skin leads to increased local GC generation, which may account for adverse changes occurring in the elderly, and 11β-HSD1 inhibitors may be useful in the treatment of age-associated impairments in dermal integrity and wound healing.

Treatment of Complex Regional Pain Syndrome (CRPS) using low dose naltrexone (LDN)

Complex Regional Pain Syndrome (CRPS) is a neuropathic pain syndrome, which involves glial activation and central sensitization in the central nervous system. Here, we describe positive outcomes of two CRPS patients, after they were treated with low-dose naltrexone (a glial attenuator), in combination with other CRPS therapies. Prominent CRPS symptoms remitted in these two patients, including dystonic spasms and fixed dystonia (respectively), following treatment with low-dose naltrexone (LDN). LDN, which is known to antagonize the Toll-like Receptor 4 pathway and attenuate activated microglia, was utilized in these patients after conventional CRPS pharmacotherapy failed to suppress their recalcitrant CRPS symptoms.

Neuroinflammation, neuroautoimmunity, and the co-morbidities of complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is associated with non-dermatomal patterns of pain, unusual movement disorders, and somatovisceral dysfunctions. These symptoms are viewed by some neurologists and psychiatrists as being psychogenic in origin. Recent evidence, however, suggests that an autoimmune attack on self-antigens found in the peripheral and central nervous system may underlie a number of CRPS symptoms. From both animal and human studies, evidence is accumulating that neuroinflammation can spread, either anterograde or retrograde, via axonal projections in the CNS, thereby establishing neuroinflammatory tracks and secondary neuroinflammatory foci within the neuraxis. These findings suggest that neuroinflammatory lesions, as well as their associated functional consequences, should be evaluated during the differential diagnosis of non-dermatomal pain presentations, atypical movement disorders, as well as other "medically unexplained symptoms", which are often attributed to psychogenic illness.

Imaging biomarkers and the role of neuroinflammation in neuropathic pain

The papers from this thematic issue followed a translational research workshop, Imaging Neuroinflammation and Neuropathic Pain, that focused on the search for neuroimaging biomarkers to assess neuroinflammation associated with neuropathic pain. The topics covered in this issue include overviews of the historical and current knowledge regarding neuropathic pain, the potential mechanisms involved, the often under-recognized clinical presentations that can delay diagnosis, the various neuroimaging techniques that have been applied to evaluate neuropathic pain and neuroinflammation, to case series illustrating novel treatments of neuropathic pain. Furthermore, the use of telemedicine to disseminate knowledge and improve the diagnosis and treatment of pain syndromes is also discussed.

Vitamin D to prevent acute lung injury following oesophagectomy (VINDALOO): study protocol for a randomised placebo controlled trial

Background

Acute lung injury occurs in approximately 25% to 30% of subjects undergoing oesophagectomy. Experimental studies suggest that treatment with vitamin D may prevent the development of acute lung injury by decreasing inflammatory cytokine release, enhancing lung epithelial repair and protecting alveolar capillary barrier function.

Methods/Design

The ‘Vitamin D to prevent lung injury following oesophagectomy trial’ is a multi-centre, randomised, double-blind, placebo-controlled trial. The aim of the trial is to determine in patients undergoing elective transthoracic oesophagectomy, if pre-treatment with a single oral dose of vitamin D₃ (300,000 IU (7.5 mg) cholecalciferol in oily solution administered seven days pre-operatively) compared to placebo affects biomarkers of early acute lung injury and other clinical outcomes. The primary outcome will be change in extravascular lung water index measured by PiCCO® transpulmonary thermodilution catheter at the end of the oesophagectomy. The trial secondary outcomes are clinical markers indicative of lung injury: PaO₂:FiO₂ ratio, oxygenation index; development of acute lung injury to day 28; duration of ventilation and organ failure; survival; safety and tolerability of vitamin D supplementation; plasma indices of endothelial and alveolar epithelial function/injury, plasma inflammatory response and plasma vitamin D status. The study aims to recruit 80 patients from three UK centres.

Discussion

This study will ascertain whether vitamin D replacement alters biomarkers of lung damage following oesophagectomy.

Trial registration

Current Controlled Trials ISRCTN27673620

Characterisation of fibroblast-like synoviocytes from a murine model of joint inflammation

Introduction

Fibroblast-like synoviocytes (FLS) play a central role in defining the stromal environment in inflammatory joint diseases. Despite a growing use of FLS isolated from murine inflammatory models, a detailed characterisation of these cells has not been performed.

Methods

In this study, FLS were isolated from inflamed joints of mice expressing both the T cell receptor transgene KRN and the MHC class II molecule Ag7 (K/BxN mice) and their purity in culture determined by immunofluorescence and real-time reverse transcription polymerase chain reaction (real-time RT-PCR). Basal expression of proinflammatory genes was determined by real-time RT-PCR. Secreted interleukin 6 (IL-6) was measured by enzyme-linked immunosorbent assay (ELISA), and its regulation by tumor necrosis factor-alpha (TNF-α and corticosterone (the major glucocorticoid in rodents) measured relative to other mesenchymal cell populations.

Results

Purity of FLS culture was identified by positive expression of fibronectin, prolyl 4-hydroxylase, cluster of differentiation 90.2 (CD90.2) and 248 (CD248) in greater than 98% of the population. Cultured FLS were able to migrate and invade through matrigel, a process enhanced in the presence of TNF-α. FLS isolated from K/BxN mice possessed significantly greater basal expression of the inflammatory markers IL-6, chemokine ligand 2 (CCL-2) and vascular cell adhesion molecule 1 (VCAM-1) when compared to FLS isolated from non-inflamed tissue (IL-6, 3.6 fold; CCL-2, 11.2 fold; VCAM-1, 9 fold; P < 0.05). This elevated expression was abrogated in the presence of corticosterone at 100 nmol/l. TNF-α significantly increased expression of all inflammatory markers to a much greater degree in K/BxN FLS relative to other mesenchymal cell lines (K/BxN; IL-6, 40.8 fold; CCL-2, 1343.2 fold; VCAM-1, 17.8 fold; ICAM-1, 13.8 fold; P < 0.05), with secreted IL-6 mirroring these results (K/BxN; con, 169 ± 29.7 versus TNF-α, 923 ± 378.8 pg/ml/1 × 10⁵ cells; P < 0.05). Dose response experiments confirmed effective concentrations between 10 and 100 nmol/l for corticosterone and 1 and 10 ng/ml for TNF-α, whilst inflammatory gene expression in FLS was shown to be stable between passages four and seven.

Conclusions

This study has established a well characterised set of key inflammatory genes for in vitro FLS culture, isolated from K/BxN mice and non-inflamed wild-type controls. Their response to both pro- and anti-inflammatory signalling has been assessed and shown to strongly resemble that which is seen in human FLS culture. Additionally, this study provides guidelines for the effective characterisation, duration and treatment of murine FLS culture.

The mesenchymal stem cell marker CD248 (endosialin) is a negative regulator of bone formation in mice

OBJECTIVE

CD248 (tumor endothelial marker 1/endosialin) is found on stromal cells and is highly expressed during malignancy and inflammation. Studies have shown a reduction in inflammatory arthritis in CD248-knockout (CD248(-/-) ) mice. The aim of the present study was to investigate the functional effect of genetic deletion of CD248 on bone mass.

METHODS

Western blotting, polymerase chain reaction, and immunofluorescence were used to investigate the expression of CD248 in humans and mice. Micro-computed tomography and the 3-point bending test were used to measure bone parameters and mechanical properties of the tibiae of 10-week-old wild-type (WT) or CD248(-/-) mice. Human and mouse primary osteoblasts were cultured in medium containing 10 mM β-glycerophosphate and 50 μg/ml ascorbic acid to induce mineralization, and then treated with platelet-derived growth factor BB (PDGF-BB). The mineral apposition rate in vivo was calculated by identifying newly formed bone via calcein labeling.

RESULTS

Expression of CD248 was seen in human and mouse osteoblasts, but not osteoclasts. CD248(-/-) mouse tibiae had higher bone mass and superior mechanical properties (increased load required to cause fracture) compared to WT mice. Primary osteoblasts from CD248(-/-) mice induced increased mineralization in vitro and produced increased bone over 7 days in vivo. There was no decrease in bone mineralization and no increase in proliferation of osteoblasts in response to stimulation with PDGF-BB, which could be attributed to a defect in PDGF signal transduction in the CD248(-/-) mice.

CONCLUSION

There is an unmet clinical need to address rheumatoid arthritis-associated bone loss. Genetic deletion of CD248 in mice results in high bone mass due to increased osteoblast-mediated bone formation, suggesting that targeting CD248 in rheumatoid arthritis may have the effect of increasing bone mass in addition to the previously reported effect of reducing inflammation.