Glucocorticoids in the treatment of rheumatic diseases: an update on the mechanisms of action

Blood content of tyrosine is an index of glucocorticoid action on metabolism

Glucocorticoid hormones directly or indirectly control virtually all metabolic and physiological processes. Glucocorticoids are also shown to act on a multitude of genes, enzyme systems, and proinflammatory factors, but for these hormones there is no representative index of action on metabolism similar to glucose content in blood for insulin. The absence of such an index prevents the assessment of tissue provision with these hormones under various conditions and seems to be an essential cause of complications associated with the clinical use of glucocorticoid preparations. Considering specific features of tyrosine metabolism and data obtained experimentally and on a clinical model (adrenalectomy in rats and substitution therapy in endocrine disease), blood content of this amino acid seems promising as such an index. Based on comparing results of glucocorticoid treatment in patients with systemic lupus erythematosus with changes in their blood tyrosine contents, the pharmacological effect of glucocorticoid preparations is suggested to be mainly due to compensating a relative shortage of these hormones.

Hypothalamus-Pituitary-Adrenal Axis Function in Patients with Rheumatoid Arthritis Treated with Nighttime-Release Prednisone

Objective.

To investigate the effects of longterm low-dose chronotherapy with modified-release (MR) prednisone for rheumatoid arthritis (RA) on the hypothalamus-pituitary-adrenal (HPA) axis as part of the Circadian Administration of Prednisone in Rheumatoid Arthritis (CAPRA-1) study. This consisted of a 3-month active-controlled phase and a 9-month open-label extension with MR prednisone including patients previously treated with prednisone (ClinicalTrials.gov number NCT00146640).

Methods.

Corticotropin-releasing hormone (CRH) tests were performed on 28 patients at 3 timepoints: at baseline on prestudy immediate-release (IR) prednisone, after the 3-month double-blind phase on either IR prednisone or MR prednisone, and after the 9-month open-label extension on MR prednisone. Changes of cortisol were assessed and compared to individual patients’ efficacy and safety data.

Results.

The increase (mean, SD) of cortisol plasma concentrations after injection of corticorelin was 5.5 (4.37) μg/dl on IR prednisone at baseline (n = 21) and 5.3 (4.07) μg/dl on MR prednisone at 12 months (n = 22). Numbers of normal/suppressed/no response reactions did not differ among treatments. Switching from IR to MR prednisone did not influence responses, nor did longterm treatment of up to 12 months with MR prednisone. No worsening of adrenal impairment was observed on treatment with nighttime-release prednisone in patients with low responsiveness to CRH testing before the treatment with MR prednisone.

Conclusion.

Treatment with nighttime-release prednisone did not change adrenocortical function over 12 months. We presume that chronotherapy with this nighttime-release prednisone may improve the efficacy of longterm low-dose glucocorticoid treatment in patients with RA.

Structure guided design of 5-arylindazole glucocorticoid receptor agonists and antagonists

Glucocorticoid receptor (GR) agonists have been used for more than half a century as the most effective treatment of acute and chronic inflammatory conditions despite serious side effects that accompany their extended use that include glucose intolerance, muscle wasting, skin thinning, and osteoporosis. As a starting point for the identification of GR ligands with an improved therapeutic index, we wished to discover selective nonsteroidal GR agonists and antagonists with simplified structure compared to known GR ligands to serve as starting points for the optimization of dissociated GR modulators. To do so, we selected multiple chemical series by structure guided docking studies and evaluated GR agonist activity. From these efforts we identified 5-arylindazole compounds that showed moderate binding to the glucocorticoid receptor (GR) with clear opportunities for further development. Structure guided optimization was used to design arrays that led to potent GR agonists and antagonists. Several in vitro and in vivo experiments were utilized to demonstrate that GR agonist 23a (GSK9027) had a profile similar to that of a classical steroidal GR agonist.

Baiting proteins with C60

About 20 proteins are known to modify their activity upon interaction with C60. Their structures are present in a database that includes more than 1200 protein structures selected as possible targets for drugs and to represent the entire Protein Data Bank. The set was examined with an algorithm that appraises quantitatively the interaction of C60 and the surface of each protein. The redundancy of the set allows to establish the predictive power of the approach that finds explicitly the most probable site where C60 docks on each protein. About 80% of the known fullerene binding proteins fall in the top 10% of scorers. The close match between the model and experiments vouches for the accuracy of the model and validates its predictions. The sites of docking are shown and discussed in view of the existing experimental data available for protein-C60 interaction. A closer exam of the 10 top scorers is discussed in detail. New proteins that can interact with C60 are identified and discussed for possible future applications as drug targets and fullerene derivatives bioconjugate materials.

Conservative treatments for rheumatoid arthritis in the foot and ankle

Rheumatoid arthritis (RA) is a systemic inflammatory disease that attacks peripheral joints, causing their destruction. Several pharmacologic therapies and physical modalities are available for its treatment. Because of the progressive nature of RA, complementary and alternative medicine therapy in conjunction with conventional medicine is administered to patients with RA. This article discusses the presence of undiagnosed RA in the foot and ankle and reviews the concurrent nonoperative measures in treatment, including pharmacologic and physical modalities.

Separating therapeutic efficacy from glucocorticoid side-effects in rodent arthritis using novel, liposomal delivery of dexamethasone phosphate: long-term suppression of arthritis facilitates interval treatment

INTRODUCTION

Glucocorticoids have extensively been used in the treatment of rheumatoid arthritis and other inflammatory diseases. However, their side-effects remain the major limitation in clinical use and an improved therapeutic index is needed.

METHODS

Therapeutic efficacy and persistence of free and liposomal dexamethasone phosphate (DXM-P) were determined in mouse collagen-induced arthritis. For regimens with equal therapeutic benefit, the side-effect profiles were analysed over time with respect to collagen breakdown, suppression of the hypothalamus-pituitary-adrenal (HPA) axis, changes in blood glucose levels and the haematological profile. In addition, the presence of drug was monitored in plasma.

RESULTS

Liposomal DXM-P, but not free drug, resulted in a persistent anti-inflammatory effect. Comparable clinical benefit was achieved with a single administration of 4 mg/kg liposomal DXM-P or daily administrations of 1.6 mg/kg free drug for at least 7 days. For the liposomal form, but not for the free form, we observed a limitation of the suppression of the HPA axis in time and an absence of the drug-induced gluconeogenesis.

CONCLUSIONS

Liposomal DXM-P, but not free DXM-P, achieves therapeutic persistence in mouse collagen-induced arthritis, which results in drug-free periods of therapeutic benefit. The physical absence of drug after day 2 is associated with a reduction of the typical glucocorticoid side-effects profile. Liposomal DXM-P thereby has an improved therapeutic window.

Pretreatment with R(+)-verapamil significantly reduces mortality and cytokine expression in murine model of septic shock

It is well known that cytokines play an important role in the pathogenesis of sepsis and septic shock. There is evidence indicating that the membrane transporter, P-glycoprotein (P-gp), may be involved in the release of cytokines, such as IL-2, IL-4 or IFN-gamma. The aim of this study was to assess the influence of P-gp inhibitor, R(+)-verapamil, on cytokine expression in serum and tissues as well as survival rate of mice with LPS-induced septic shock. These effects were compared with the response to treatment with pentoxifylline, lisofylline, and prednisolone administered alone or after pretreatment with R(+)-verapamil. When given as a single agent, R(+)-verapamil significantly decreased serum levels of TNF-alpha and IFN-gamma and protected mice from endotoxin lethality. Moreover, it decreased up-regulated by LPS TNF-alpha gene expression in the liver and lungs. Given concomitantly with immunomodulatory compounds, it enhanced their beneficial impact on the survival of mice with septic shock. The highest increase in survival rate was observed in combination with pentoxifylline (7% vs. 67%). The most striking differences observed between saline and R(+)-verapamil pretreated animals on combination therapy included down-regulation of TNF-alpha, higher levels of IL-6, and decreased IFN-gamma concentrations. These results suggest that P-gp may be involved in the release of IFN-gamma, and possibly also TNF-alpha, in mice with septic shock. R(+)verapamil improves survival of mice receiving a lethal dose of LPS and significantly potentiates the protective effect of pentoxifylline and prednisolone against LPS-induced lethality, probably as a result of both P-gp inhibition and a synergistic interaction at the gene level.

Treatment of focal segmental glomerulosclerosis with immunophilin modulation: when did we stop thinking about pathogenesis?

Nephrotic focal segmental glomerulosclerosis (FSGS) represents a difficult therapeutic challenge. FSGS has long been considered a subset of idiopathic nephrotic syndrome, lumping together FSGS and minimal change disease (MCD). The time-honored 'Shalhoub hypothesis' has led to treating FSGS as a T-cell-driven condition in which a lymphokine, considered without proof as being the 'glomerular permeability factor,' induces proteinuria and podocyte functional and structural derangement. This has led to trying, in addition to steroids, every new drug marketed in the field of organ transplantation, first cyclosporine (CsA) and then other immunophilin modulators. The fact that alkylating agents and mycophenolate mofetil have obtained a poor and inconstant favorable effect, and that rituximab may obtain remissions, although inconstantly, has not led to reconsidering the T-cell hypothesis. This wrong thinking has fostered innumerable, mostly uncontrolled, treatment trials with various immunosuppressive agents. In fact, clinicians have not considered the fact that some but not all immunophilin modulators may be effective as nonspecific antiproteinuric agents, rather than as immunosuppressive drugs, and that treatment success does not exclude a non-immunologic pathophysiology. Recent findings on the mode of action of CsA and FK-506 have lent support to this concept. This review should be considered as a plea to reconsider the pathogenesis of nephrotic FSGS, applying all efforts to the identification of the factor, or factors, responsible for nephrotic FSGS, and to fund treatment to counteract the 'factor,' rather than pursuing costly and non-evidence-based immunosuppressive therapeutic trials.

An update on the treatment options for focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is not a disease but a lesion initially affecting the podocyte. Various factors may induce 'secondary' FSGS, including defects in molecules that contribute to the podocyte slit diaphragm permselectivity to albumin. They do not represent indications for immunosuppression and require symptomatic treatment only, comprising angiotensin 2 and endothelin antagonists. Primary (idiopathic) FSGS is possibly but not certainly of immunologic origin, owing to an elusive glomerular permeability factor (GPF), explaining relapse on a renal transplant and justifying an immunosuppressive treatment. The best prognostic feature of primary nephrotic FSGS is its response to corticosteroids. Alkylating agents are mostly ineffective in steroid-resistant forms. An association of corticosteroids and cyclosporine A (CsA) remains the mainstay of treatment, with a good tolerability when CsA dosage is low. A definite advantage of tacrolimus on CsA has not yet been established. Sirolimus appears ineffective and potentially harmful. Azathioprine is not indicated. A number of mostly uncontrolled trials indicate that mycophenolate mofetil might find an adjunctive place in the treatment. Plasmapheresis is of no avail outside the special case of relapse in a transplanted kidney. Immunoabsorption of the GPF has not led to practical treatment options. Anecdotal reports on rituximab are as yet too few to determine whether this monoclonal anti-CD20 antibody will find a place in the treatment of primary FSGS.

Iatrogenic Cushing syndrome caused by ocular glucocorticoids in a child

A boy aged 7.6 years presented to our Unit of Paediatric Endocrinology for evaluation of obesity. Progressive weight gain (10 kg) started 6 months earlier after an accidental penetrating orbital injury on the right eye. During this period the child has been treated with oral betamethasone (0.5 mg/day) for 1 month and dexamethasone 2% ocular drops (2 hourly by day) for 6 months. Physical examination showed he was 113.5 cm in height (-1.5 SD), weight 36.0 kg, blood pressure 110/90 mmHg (90th centile), body mass index 28 (+5 SD), truncal obesity, buffalo hump, "moon-face", increased lanugo hair and supraclavicular fullness. Endocrinological work-up revealed undetectable levels of basal adrenocorticotropic hormone (ACTH), basal and ACTH-stimulated cortisol and 24 h urine excretion cortisol, confirming the diagnosis of iatrogenic Cushing syndrome. The abrupt withdrawal of ocular glucocorticoids by the parents evoked two adrenal crises; 4 months later the patient recovered. In conclusion, we would alert doctors that every formulation of glucocorticoids, no ocular drops excluded, can determine severe systemic side effects and iatrogenic Cushing syndrome.

Dynamic access of the glucocorticoid receptor to response elements in chromatin

Transcriptional activation as a rate-limiting step of gene expression is often triggered by an environmental stimulus that is transmitted through a signaling cascade to specific transcription factors. Transcription factors must then find appropriate target genes in the context of chromatin. Subsequent modulation of local chromatin domains is now recognized as a major mechanism of gene regulation. The interactions of transcription factors with chromatin structures have recently been observed to be highly dynamic, with residence times measured in seconds. Thus, the concept of static, multi-protein complexes forming at regulatory elements in the genome has been replaced by a new paradigm that envisages rapid and continuous exchange events with the template. These highly dynamic interactions are a property of both DNA-protein and protein-protein interactions and are inherent to every stage of the transcriptional response. In this review we discuss the dynamics of a nuclear receptor, and its transcriptional response in the chromatin context.

Alpha-methylprednisolone conjugated cyclodextrin polymer-based nanoparticles for rheumatoid arthritis therapy

A glycinate derivative of α-methylprednisolone (MP) was prepared and conjugated to a linear cyclodextrin polymer (CDP) with a loading of 12.4% w/w. The polymer conjugate (CDP-MP) self-assembled into nanoparticles with a size of 27 nm. Release kinetics of MP from the polymer conjugate showed a half-life (t_1/2) of 50 h in phosphate buffer solution (PBS) and 19 h in human plasma. In vitro, the proliferation of human lymphocytes was suppressed to a similar extent but with a delayed effect when CDP-MP was compared with free MP. In vivo, CDP-MP was administered intravenously to mice with collagen-induced arthritis and compared with free MP. CDP-MP was administered weekly for six weeks (0.07, 0.7, and 7 mg/kg/week) and MP was administered daily for six weeks (0.01, 0.1, and 1 mg/kg/day). Body weight changes were minimal in all animals. After 28 days, a significant decrease in arthritis score was observed in animals treated weekly with an intermediate or high dose of CDP-MP. Additionally, dorsoplantar swelling was reduced to baseline in animals treated with CDP-MP at the intermediate and high dose level. Histological evaluation showed a reduction in synovitis, pannus formation and disruption of architecture at the highest dose level of CDP-MP. MP administered daily at equivalent cumulative doses showed minimal efficacy in this model. This study demonstrates that conjugation of MP to a cyclodextrin-polymer may improve its efficacy, leading to lower doses and less frequent administration for a safer and more convenient management of rheumatoid arthritis.

Therapeutic Application of Long-Circulating Liposomal Glucocorticoids in Auto-Immune Diseases and Cancer

Glucorticoids are potent drugs that have a multitude of pharmacological actions both at genomic and non-genomic levels. Many of the diseases in which glucorticoids are routinely administered are featured by angiogenesis and enhanced capillary permeability, permitting targeted delivery using long-circulating drug delivery systems. By encapsulation of glucorticoids in long-circulating liposomes, drug levels at the site of the pathology are markedly higher, increasing and prolonging therapeutic efficacy in models of rheumatoid arthritis, multiple sclerosis, and cancer.

[Glucocorticoids in rheumatology]

Glucocorticoids (GC) are effective drugs which are often used in rheumatology. However, they have a considerable potential for frequent and sometimes serious side effects that restrict their use. Their mechanisms of action are either receptor dependent (specific) or independent (unspecific) on the genomic as well as the non-genomic level. Many adverse effects are predominantly caused by transactivation while the desired effects are mostly mediated by transrepression. Treatment strategies are sub-classified into low, medium, high, very high dose and pulse therapy based on criteria such as dose, indication, duration of treatment and potential risk of adverse events. The musculoskeletal, gastrointestinal, neuro-endocrino-immunological, opthalmological and neuropsychiatric systems are examples where adverse effects may occur.

Novel insights into mechanisms of glucocorticoid action and the development of new glucocorticoid receptor ligands

Glucocorticoids (GCs) are potent anti-inflammatory and immunosuppressant agents. Unfortunately, they also produce serious side effects that limit their usage. This discrepancy is the driving force for the intensive search for novel GC receptor ligands with a better benefit-risk ratio as compared to conventional GCs. A better understanding of the molecular mode of GC action might result in the identification of novel drug targets. Genomic GC effects are mediated by transrepression or transactivation, the latter being largely responsible for GC side effects. We here discuss novel GC receptor ligands, such as selective glucocorticoid receptor agonists (SEGRAs), which might optimize genomic GC effects as they preferentially induce transrepression with little or no transactivating activity. In addition to genomic GC effects, GCs also produce rapid genomic-independent activities, termed nongenomic, and we here review the possible implications of a recently reported mechanism underlying nongenomic GC-induced immunosuppression in T cells. It was shown that the synthetic GC dexamethasone targets membrane-bound GC receptors leading to impaired T cell receptor signaling. As a consequence, membrane-linked GC receptors might be a potential candidate target for GC therapy. The ultimate goal is to convert these molecular insights into new GC receptor modulators with an improved therapeutic index.

Genomic and nongenomic effects of glucocorticoids

The strong anti-inflammatory and immunosuppressive effects of glucocorticoids are mediated primarily by the cytosolic glucocorticoid receptors. These receptors are members of the steroid hormone receptor family, a superfamily of ligand-inducible transcription factors, and exert genomic effects that can result in increased expression of regulatory-including anti-inflammatory-proteins (transactivation), or decreased production of proinflammatory proteins (transrepression). Transactivation is thought to be responsible for numerous adverse effects of glucocorticoids; transrepression is thought to be responsible for many of the clinically desirable anti-inflammatory and immunosuppressive effects of glucocorticoids. Optimized glucocorticoids, such as selective glucocorticoid receptor agonists, are being developed to try to minimize the adverse effects many patients experience. Glucocorticoids also exert their effects via rapid, nongenomic mechanisms that can be classified as involving nonspecific interactions of glucocorticoids with cellular membranes, nongenomic effects that are mediated by cytosolic glucocorticoid receptors, or specific interactions with membrane-bound glucocorticoid receptors. Increased understanding of these mechanisms of glucocorticoid action could enable the development of novel drugs with which to treat patients with inflammatory and autoimmune disease.

Glucocorticoid-induced leucine zipper (GILZ) mediates glucocorticoid action and inhibits inflammatory cytokine-induced COX-2 expression

Cyclooxygenase-2 (COX-2) plays an important role in rheumatoid arthritis and therefore, has been a major target for anti-arthritis therapies. The expression of COX-2 is induced by inflammatory cytokines such as TNF-alpha and IL-1beta, and inhibited by glucocorticoids. However, the molecular mechanisms underlying the anti-inflammatory and immune suppressive actions of glucocorticoids are not well defined. Here we report that glucocorticoid-induced leucine zipper (GILZ) mimics glucocorticoid action and inhibits inflammatory cytokine-induced COX-2 expression in bone marrow mesenchymal stem cells, the cells that have been recently implicated in the pathogenesis and progression of rheumatoid arthritis. Using a retrovirus-mediated gene expression approach we demonstrate that overexpression of GILZ inhibits TNF-alpha and IL-1beta-induced COX-2 mRNA and protein expression, and knockdown of GILZ by shRNA reduces glucocorticoid inhibition of cytokine-induced COX-2 expression. Consistent to these results, overexpression of GILZ also inhibits NF-kappaB-mediated COX-2 promoter activity. Finally, we show that GILZ inhibits COX-2 expression by blocking NF-kappaB nuclear translocation. Our results suggest that GILZ is a key glucocorticoid effect mediator and that GILZ may have therapeutic value for novel anti-inflammation therapies.

Liposomal glucocorticoids as tumor-targeted anti-angiogenic nanomedicine in B16 melanoma-bearing mice

This study evaluates whether the inhibitory effects of prednisolone phosphate (PLP) encapsulated in long-circulating liposomes (LCL-PLP) on tumor growth and tumor angiogenesis described previously can be generalized to other types of glucocorticoids (GC) encapsulated in LCL (LCL-GC). Four types of synthetic GC, i.e. budesonide disodium phosphate (BUP), dexamethasone disodium phosphate (DXP), methylprednisolone disodium phosphate (MPLP), and PLP, were selected based on the difference in their potency to activate the human glucocorticoid receptor. The effects of all LCL-GC on the production of angiogenic/inflammatory factors in vivo in the B16.F10 murine melanoma model as well as on the viability and proliferation of tumor cells and endothelial cells in vitro were investigated. Our results show that all four selected LCL-GC formulations inhibit tumor growth, albeit to different degrees. The differences in antitumor activity of LCL-GC correlate with their efficacy to suppress tumor angiogenesis and inflammation. The strongest antitumor effect is achieved by LCL-encapsulated BUP (LCL-BUP), due to the highest potency of BUP versus the other three GC types. The in vitro results presented herein suggest that LCL-BUP has strong cytotoxic effects on B16.F10 melanoma cells and the anti-proliferative effects of all LCL-GC towards angiogenic endothelial cells play a role in their antitumor activity.

The Development of Novel Therapies for Rheumatoid Arthritis

BACKGROUND: Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory disease that affects approximately 0.5 to 1 percent of the adults worldwide and commonly results in joint destruction and significant impairment in the quality of life. RA is considered as an autoimmune disease with unknown etiology. Many pathogenic pathways of RA have been revealed recently, which led to development of various novel therapies. OBJECTIVE: The current treatments of RA include 4 categories: non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, non-biologic disease-modifying anti-rheumatic drugs (DMARDs) and biologic DMARDs. In this review, we will discuss some of the most recent development in antirheumatic therapies. METHODS: Using SciFinder Scholar and PubMed as main searching tools, we evaluated various newly developed therapies for RA. Under each drug category, emphases are placed on the mode of action, limitation of the drugs and new drug candidates from the patents search. Those well-established therapies will only be reviewed briefly. CONCLUSION: During the past 20 years, most of the development of new therapies is in DMARDs, especially biological DMARDs. With the discovery of new pathways and the application of drug delivery strategies, more growth is anticipated in this research field.

Dexamethasone inhibits BAFF expression in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Fibroblast-like synoviocytes (FLS) play a major role in the pathogenesis of rheumatoid arthritis (RA). FLS isolated from patients with RA (FLS-RA) express B cell-activating factor belonging to the TNF family (BAFF), a cytokine that has been associated with the onset and progression of RA. Glucocorticoids are powerful anti-inflammatory drugs used in the treatment of RA. In the present study, we examined the effect of dexamethasone (Dex) on constitutive and TNF-alpha- and IFN-gamma-induced BAFF expression in FLS-RA. BAFF mRNA expression and soluble BAFF were determined by RT-PCR and ELISA, respectively. The results showed that constitutive BAFF mRNA expression was inhibited by Dex in a dose- and time-dependent manner. Also, Dex inhibited the secretion of BAFF in a time-dependent manner reaching 76% of inhibition 72 h after treatment. Moreover, Dex suppressed both mRNA and protein BAFF expression induced by TNF-alpha but had no effect on IFN-gamma-induced BAFF expression. In comparison with B cells cultured alone, B cells co-cultured with FLS-RA exhibited a higher survival, which was inhibited when FLS-RA were pretreated with Dex. However, the enhanced B cell survival was reestablished by the addition of rhBAFF. Therefore, Dex is a potent inhibitor of constitutive and TNF-alpha-induced BAFF expression in FLS-RA.

Caveolin mediates rapid glucocorticoid effects and couples glucocorticoid action to the antiproliferative program

Many glucocorticoid (Gc) actions are of rapid onset and therefore require acute regulation of intracellular signaling cascades. Integration of diverse extracellular signals requires cross-talk between intracellular pathways, suggesting the existence of nodes for signal interaction, such as the specialized membrane microdomains caveolae. We have identified rapid Gc-dependent phosphorylation of caveolin, and protein kinase B (PKB)/Akt, in the lung epithelial cell line A549 and found this was dependent on src kinases. There was also activation of PKB downstream molecules glycogen synthase kinase-3beta, and mammalian target of rapamycin. Subcellular fractionation colocalized glucocorticoid receptor (GR) and c-src to caveolin-containing membrane fractions. Coimmunoprecipitation studies also identified interactions between GR and caveolin and suggested that the activation function 1 domain within the GR may serve to support an interaction between GR and caveolin. Disruption of lipid raft formation, impairment of caveolin function using dominant-negative caveolin, down-regulation of caveolin-1 using short hairpin RNA or complete ablation of caveolin-1 prevented Gc-induced activation of PKB. Loss of caveolin-1 also prevents Gc activation of glycogen synthase kinase-3beta and mammalian target of rapamycin. In contrast, caveolin interference/down-regulation had no effect on Gc transactivation. Functional analysis of caveolin-1 knockdown and knockout cells identified profound loss of Gc-mediated growth inhibition compared with controls, with a requirement for caveolin in order for Gc to regulate cell cycle progression. Therefore, disruption of caveolae leads to dissociation of Gc action, with impaired induction of PKB activation, and cell growth inhibition, but with negligible effects on Gc transactivation. These observations have implications for understanding the diverse physiological actions of Gc.

Efficacy of modified-release versus standard prednisone to reduce duration of morning stiffness of the joints in rheumatoid arthritis (CAPRA-1): a double-blind, randomised controlled trial

BACKGROUND

Circadian rhythms are changed in patients with rheumatoid arthritis. A new modified-release delivery system has been developed which adapts the release of the administered glucocorticoid to the circadian rhythms of endogenous cortisol and disease symptoms to improve the benefit-risk ratio of glucocorticoid therapy in rheumatoid arthritis. We aimed to assess the efficacy and safety of a new modified-release prednisone tablet compared with immediate-release prednisone in patients with this disease.

METHODS

In a 12-week, multicentre, randomised, double-blind trial, 288 patients with active rheumatoid arthritis were randomly assigned to either a modified-release prednisone tablet (n=144) or to an immediate-release prednisone tablet (n=144). The modified-release tablet was taken at bedtime and prednisone was released with a delay of 4 h after ingestion. This treatment was compared with morning administration of immediate-release prednisone as an active comparator. The primary outcome measure was duration of morning stiffness of the joints. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00146640.

FINDINGS

The mean relative change in duration of morning stiffness of the joints from baseline to end of treatment was significantly higher with modified-release prednisone than with immediate-release prednisone (-22.7%vs -0.4%; difference=22.4% [95% CI 0.49-44.30]; p=0.045). Patients in the prednisone modified-release group achieved a mean reduction of 44.0 (SD 136.6) min compared with baseline. The absolute difference between the treatment groups was 29.2 min (95% CI -2.59 to 61.9) in favour of modified-release prednisone (p=0.072). The safety profile did not differ between treatments.

INTERPRETATION

Modified-release prednisone is well tolerated, convenient to administer, and produces a clinically relevant reduction of morning stiffness of the joints in addition to all known therapeutic effects of immediate-release prednisone.

Short-term effects of glucocorticoid therapy on biochemical markers of bone metabolism in Japanese patients: a prospective study

Glucocorticoid (GC) therapy induces rapid bone loss, but the early changes in calcium and bone metabolism in patients treated with GC have not been clarified. To investigate the changes in calcium and bone metabolism during the early stage of GC therapy, we analyzed various biochemical markers of bone metabolism. The serum levels of calcium (Ca), phosphorus, parathyroid hormone (PTH), osteocalcin (OC), bone alkaline phosphatase (BAP), and type I collagen cross-linked N-telopeptide (NTx), as well as the urinary levels of Ca, creatinine, and NTx, were measured on days 0, 3, 7, and 28 of GC therapy. The subjects were divided into the following four groups: 9 patients receiving pulse therapy (P), 18 patients receiving prednisolone (PSL) at doses > or =40 mg/day (H), 9 patients receiving PSL at doses > or =20 mg/day (M), and 11 patients receiving PSL at doses < or =10 mg/day (S). The serum OC level showed a marked decrease on day 3 of GC therapy (-41.2% +/- 6.6%, P < 0.01), while the BAP level decreased gradually. Both serum and urinary NTx levels significantly increased on day 7 of GC therapy (9.9% +/- 4.5%, P < 0.05, and 42.2% +/- 10.6%, P < 0.01, respectively). Urinary Ca excretion was increased on day 3 of GC therapy and continued to increase until 4 weeks, while intact PTH showed an increase on day 3 and then remained constant until 4 weeks. In groups P and H, there were significant early changes in OC, BAP, NTx, and intact PTH levels, as well as urinary Ca excretion. Even a PSL dose of <10 mg/day caused a decrease in the serum OC level. In conclusion, the biochemical markers of Ca and bone metabolism showed different kinetics depending on the dose of GC, and it is important for patients on high-dose GC therapy to receive prophylaxis for bone loss from the start of GC treatment.

Oral beclomethasone dipropionate: a topically active corticosteroid for the treatment of gastrointestinal graft-versus-host disease following allogeneic hematopoietic cell transplantation

Beclomethasone dipropionate (BDP) is a topically active anti-inflammatory corticosteroid. Oral BDP is metabolized in the intestine to a potent metabolite, 17-beclomethasone monopropionate (17-BMP). An oral formulation (orBec; DOR BioPharma), consisting of a gastric release and an enteric-coated pill, was studied in patients with acute gastrointestinal graft-versus-host disease, an inflammatory disorder that is common after allogeneic hematopoietic cell transplantation. Randomized trials demonstrated that orBec is safe and effective in treating acute gastrointestinal graft-versus-host disease (GVHD) when used with a short induction course of prednisone, reducing the risk of GVHD treatment failure by > 60% and reducing mortality 1 year after randomization by 45%, with fewer deaths due to infection and recurrent malignancy. The type of conditioning and the type of donor had no effect on the frequency of GVHD treatment failure during the 80-day study period; the greatest benefit in terms of survival was among patients who had received reduced-intensity conditioning therapy and among those who received a graft from other than a human leukocyte antigen-matched sibling. orBec controls the intestinal inflammatory process of GVHD and avoids prolonged exposure to prednisone, which is the present standard of care. Oral BDP is the only therapy to be studied in the last 30 years to effectively treat acute GVHD and reduce mortality.

Synergistic interaction between dexamethasone and tramadol in a murine model of acute visceral pain

Tramadol is effective in the management of mild to moderate postoperative pain, but its administration is associated with nausea and vomiting. Patients treated with tramadol, often receive dexamethasone as antiemetic. The aim of our investigation was to assess if the two drugs interact in a murine model of acute visceral pain. Using the acetic acid writhing test in mice, we assessed the antinociceptive effects of tramadol and dexamethasone (a glucocorticoid with antiemetic effect) administrated individually and in a 1 : 1 fixed ratio combination. Tramadol and dexamethasone induced a dose-dependent inhibition of the writhing response when administered individually, with ED(50) values of 2.9 [2.09-4.31, 95% confidence limit (CL)] mg/kg, and 0.13 (0.05-0.29, 95% CL) mg/kg, respectively. The ED(50) of the combination was 0.13 (0.01-0.29, 95% CL) mg/kg; the isobolographic and interaction index analysis revealed a synergistic interaction. The results suggest that the combination of tramadol and dexamethasone could be beneficial in the management of postoperative pain in humans.

Molecular mechanisms of glucocorticoid action and selective glucocorticoid receptor agonists

Glucocorticoids (GC) are the most common used anti-inflammatory and immunosuppressive drugs in the treatment of rheumatic and other inflammatory diseases. Their therapeutic effects are considered to be mediated by four different mechanisms of action: the classical genomic mechanism of action caused by the cytosolic glucocorticoid receptor (cGCR); secondary non-genomic effects which are also initiated by the cGCR; membrane-bound glucocorticoid receptor (mGCR)-mediated non-genomic effects; non-specific, non-genomic effects caused by interactions with cellular membranes. The classical, genomic mechanism of GC-action can be divided into two processes: "transrepression", which is responsible for a large number of desirable anti-inflammatory and immunomodulating effects, and "transactivation" which is associated with frequently occurring side effects as well as with some immunosuppressive activities [Ehrchen, J., Steinmuller, L., Barczyk, K., Tenbrock, K., Nacken, W., Eisenacher, M., Nordhues, U., Sorg, C., Sunderkotter, C., Roth, J., 2007. Glucocorticoids induce differentiation of a specifically activated, anti-inflammatory subtype of human monocytes. Blood 109, 1265-1274]. Great efforts have been made to diminish glucocorticoid-induced adverse effects, but the improvement of conventional glucocorticoids has almost reached its limits. As a consequence, new variations of the conventional "good old drugs" are being tested and nitro-steroids and long circulating liposomal glucocorticoids indeed show promising results. Nevertheless, crux of the matter should be the design of qualitatively new drugs, such as selective glucocorticoid receptor agonists (SEGRAs). These innovative steroidal or non-steroidal molecules induce transrepression, while transactivation processes are less affected. First reports on two different GCR ligands, A276575 and ZK216348, show promising results. Here, we review the above-mentioned mechanisms of glucocorticoid action and give particular attention to the development of optimized glucocorticoids and SEGRAs.

Targeting of memory

Current therapeutic options that are based on immunosuppression do not provide a cure for the treatment of chronic inflammation. Though more efficient immunosuppression and the introduction of biologicals such as antibodies targeting cytokines have improved clinical outcomes, immunosuppressive therapy has to be continued to be efficient, thus enhancing the risk of adverse events and undesired side effects. Why can immunosuppression ameliorate, even stop, but not cure chronic inflammation? Is chronic inflammation perpetuated beyond suppression by mechanisms independent of the immune system, or is it perpetuated by components of the immune system which are resistant to a block of ongoing immune reactions? One such component of the immune system is immunological memory. This article will review the role of immunological memory in chronic inflammation, as far as we understand it today, and discuss implications for the development of novel therapeutic strategies aiming at a cure for diseases involving chronic inflammation.

Non-steroidal glucocorticoid agonists: the discovery of aryl pyrazoles as A-ring mimetics

Starting from an established series of non-steroidal glucocorticoid receptor (GR) agonists, a large array was designed where a metabolically labile benzoxazinone moiety was replaced. Initial hits bound to GR but lacked agonist activity. Following two further iterations, potent GR agonists were discovered with 20D1E1 having NFkappaB agonism pIC(50) 8.8 (103%). Other analogues such as 23D1E1 display a dissociated profile (NFkappaB pIC(50) 8.1 (103%), MMTV pEC(50) 7.02 (36%)). The tetrahydronaphthalene moiety can also be replaced with substituted aryls such as 24E1 and 25E1.

Krankheitsmodifizierende Effekte bei der rheumatoiden Arthritis durch Glukokortikoide

Drugs used for managing rheumatoid arthritis (RA) are designated disease-modifying antirheumatic drugs (DMARDs) if they reduce inflammation and pain, limit joint destruction, and improve long-term disease outcome. Glucocorticoids have long been known to have anti-inflammatory, immunosuppressive, and pain-reducing effects. Moreover, they have been shown in recent clinical trials, and also very recently in a systemic analysis of the results of these studies, to contribute to inhibition of the radiographic progression of RA. For these reasons, glucocorticoids can be considered DMARDs if they are used to treat patients suffering from early RA and, according to the current knowledge, are used in combination with other DMARDs.

Gelatinase expression and proteolytic activity in giant-cell arteritis

OBJECTIVES

Gelatinases (MMP2 and MMP9) are expressed in giant-cell arteritis (GCA) and are thought to play a role in vessel disruption. However, their activation status and enzymatic activity have not been evaluated. Our aim was to investigate the distribution and proteolytic activity of gelatinases in GCA lesions at different stages.

METHODS

Expression of MMP2, MMP9, MMP2-activator MMP14 and their natural inhibitors TIMP1 and TIMP2 was determined by real-time PCR and immunohistochemistry in temporal artery sections from 46 patients and 12 controls. MMP activation status and enzymatic activity were assessed by gelatin and film in situ zymography.

RESULTS

Vascular smooth muscle cells from normal specimens constitutively expressed pro-MMP2 and its inhibitor TIMP2 with no resulting proteolytic activity. In GCA MMP2, MMP9 and MMP14 were strongly expressed in their active form by infiltrating leucocytes. Inflamed arteries also expressed TIMP1 and TIMP2. However, the MMP9/TIMP1 and MMP2/TIMP2 ratios were higher in patients compared with controls, indicating an increased proteolytic balance in GCA which was confirmed by in situ zymography. Maximal gelatinase expression and activity occurred at the granulomatous areas surrounding the internal elastic lamina (IEL). Myointimal cells also expressed MMPs and exhibited proteolytic activity, suggesting a role for gelatinases in vascular remodelling and repair.

CONCLUSIONS

GCA lesions show intense expression of gelatinases. Activators and inhibitors are regulated to yield enhanced gelatinase activation and proteolytic activity. Distribution of expression and proteolytic activity suggests that gelatinases have a major role not only in the progression of inflammatory infiltrates and vessel destruction but also in vessel repair.

Drug Insight: resistance to methotrexate and other disease-modifying antirheumatic drugs--from bench to bedside

The chronic nature of rheumatoid arthritis (RA) means that patients require drug therapy for many years. Many RA patients, however, have to discontinue treatment because of drug-related toxic effects, loss of efficacy, or both. The underlying molecular cause for loss of efficacy of antirheumatic drugs is not fully understood, but it might be mediated, at least in part, by mechanisms shared with resistance to anticancer drugs. This Review outlines molecular mechanisms that could be involved in the onset of resistance to, or the loss of efficacy of, disease-modifying antirheumatic drugs in RA patients, including methotrexate, sulfasalazine, chloroquine, hydroxychloroquine, azathioprine, and leflunomide. The mechanisms suggested are based on findings from experimental laboratory studies of specific drug-uptake and drug-efflux transporters belonging to the superfamily of multidrug-resistance transporters, alterations in intracellular drug metabolism, and genetic polymorphisms of drug transporters and metabolic enzymes. We also discuss strategies to overcome resistance and the current clinical studies aiming to predict response and risk of toxic effects. More in-depth knowledge of the mechanisms behind these features could help facilitate a more efficient use of disease-modifying antirheumatic drugs.

Glucocorticoid signaling: a nongenomic mechanism for T-cell immunosuppression

Glucocorticoids were long believed to exert their effects through transcriptional regulation of glucocorticoid-receptor target genes. However, there is accumulating evidence for nongenomic glucocorticoid-receptor-dependent modulation of signal transduction pathways. Here, we review rapid glucocorticoid activities and focus on a novel mechanism that underlies nongenomic glucocorticoid-induced immunosuppression in T cells. The findings demonstrate a physical and functional interaction between the glucocorticoid receptor and the T-cell receptor (TCR) complex. In its unligated state, the glucocorticoid receptor has an important role in TCR signaling but, after glucocorticoid-receptor-ligand binding (caused by short-term treatment with the synthetic glucocorticoid dexamethasone), the TCR complex is disrupted, leading to impaired TCR signaling. These data reveal a dichotomal functional role for glucocorticoid receptors: one in the cytosol as part of the TCR complex and the other as a nuclear regulator of gene transcription. Drugs that selectively target membrane-bound glucocorticoid receptors might represent a novel immunosuppressive approach.

Sulfasalazine sensitises human monocytic/macrophage cells for glucocorticoids by upregulation of glucocorticoid receptor alpha and glucocorticoid induced apoptosis

BACKGROUND

Glucocorticoids (GCs) are commonly used in the treatment of (chronic) inflammatory diseases and cancer, but inherent or acquired resistance to these drugs limits their optimal efficacy. The availability of drugs that could modulate GC resistance is therefore of potential clinical interest.

OBJECTIVE

To explore the molecular basis of GC sensitisation of GC resistant monocytic/macrophage cells after chronic exposure to sulfasalazine.

METHODS

Human monocytic/macrophage THP1 and U937 cells represent a cell line model system characterised by inherent resistance to the GCs dexamethasone and prednisolone. Both cell lines were chronically exposed in vitro to 0.3-0.6 mM sulfasalazine (SSZ) for approximately 3 months, after which they were characterised for GC sensitivity, expression levels of GC receptor and components of the nuclear factor kappa B (NFkappaB) signalling pathway, and their ability to undergo GC induced apoptosis.

RESULTS

Chronic exposure to SSZ markedly sensitised both U937 and THP1 cells to dexamethasone (781-fold and 1389-fold, respectively) and prednisolone (562-fold and 1220-fold, respectively). Restoration of GC sensitivity in cells exposed to SSZ was provoked via GC induced apoptosis, coinciding with inhibition of NFkappaB activation. Moreover, western blot analysis revealed a markedly increased expression of glucocorticoid receptor alpha (GRalpha) in cells exposed to SSZ. Since GRalpha mRNA levels were only marginally increased, these results suggest that an altered post-transcriptional mechanism was operable which conferred a stable GRalpha protein on SSZ exposed cells.

CONCLUSION

These results suggest that chronic targeting of the NFkappaB signalling pathway by SSZ may be exploited as a novel strategy to stabilise GRalpha expression and thereby sensitise primary resistant cells to GCs.

Glucocorticoids induce differentiation of a specifically activated, anti-inflammatory subtype of human monocytes

Monocytes and macrophages may either promote or down-regulate inflammatory reactions depending on their state of activation. The effects of glucocorticoids (GCs), the most widely used immunosuppressive drugs, on monocytes are currently not well defined. By analyzing the GC-induced expression pattern in human monocytes by microarray technology, we identified for the first time GC-dependent regulation of 133 genes, including anti-inflammatory molecules such as adenosine A3 receptor, CD1d, and IL-1 receptor II. The results were independently confirmed by real-time polymerase chain reaction (PCR) and flow cytometry. Functional clustering of GC-regulated genes indicated induction of monocytic properties such as phagocytosis and motility as well as repression of adhesion, apoptosis, and oxidative burst. These predictions were confirmed by independent functional assays. GCs up-regulate fMLP receptors and specifically promote chemotaxis to this chemoattractant. Furthermore, GCs promote survival of an anti-inflammatory monocytic phenotype in inflammatory reactions, probably by inhibition of apoptosis because of oxidative stress. GCs limit tissue damage because of induction of antioxidative properties and high capacity for phagocytosis of proinflammatory agents. Thus, GC treatment did not cause a global suppression of monocytic effector functions but results in differentiation of a specific anti-inflammatory phenotype which seems to be actively involved in resolution of inflammatory reactions.

Dissociated nonsteroidal glucocorticoid receptor modulators; discovery of the agonist trigger in a tetrahydronaphthalene-benzoxazine series

The tetrahydronaphthalene-benzoxazine glucocorticoid receptor (GR) partial agonist 4b was optimized to produce potent full agonists of GR. Aromatic ring substitution of the tetrahydronaphthalene leads to weak GR antagonists. Discovery of an "agonist trigger" substituent on the saturated ring of the tetrahydronaphthalene leads to increased potency and efficacious GR agonism. These compounds are efficacy selective in an NFkB GR agonist assay (representing transrepression effects) over an MMTV GR agonist assay (representing transactivation effects). 52 and 60 have NFkB pIC(50) = 8.92 (105%) and 8.69 (92%) and MMTV pEC(50) = 8.20 (47%) and 7.75 (39%), respectively. The impact of the trigger substituent on agonism is modeled within GR and discussed. 36, 52, and 60 have anti-inflammatory activity in a mouse model of inflammation after topical dosing with 52 and 60, having an effect similar to that of dexamethasone. The original lead was discovered by a manual agreement docking method, and automation of this method is also described.

Oral pulsed dexamethasone therapy in early rheumatoid arthritis: a pilot study

Pulse therapy with high-dose glucocorticoids (GCs) is widely used as "bridging therapy" for the treatment of patients with active rheumatoid arthritis (RA). Oral pulsed dexamethasone therapy has never been used for this purpose. We determined the clinical efficacy of oral pulsed dexamethasone treatment in patients with early active RA, concomitantly starting with disease-modifying anti-rheumatic drugs (DMARDs). Fourteen early RA patients, glucocorticoid-naive and with active disease for less than 1 year were included. Ten patients were treated with oral pulsed dexamethasone therapy for 4 days in a row. Of this group, four patients received 10 mg dexamethasone/day, three patients 20 mg/day, and three patients 40 mg/day. As controls, four patients were treated with intramuscular methylprednisolone injections. Disease activity (ascertained by disease activity score [DAS]) and biochemical variables were measured at base line, and biweekly thereafter for up to 4 weeks, and monthly thereafter for up to 3 months. A decrease in disease activity, similar in all subgroups, was observed. Nine of 10 patients responded favorably (decrease in DAS of >1.2) 4 weeks after the start of the study. This response was sustained in the months thereafter. One patient did not respond at all, and disease progression during treatment was observed in one patient. No side effects were reported. Only once was a decrease in cortisol level observed; this was at 2 weeks after the start of the study (0.03 micromol/L, reference value 0.18-0.70 micromol/L). Oral pulsed dexamethasone therapy seems to be effective and safe as bridging therapy in early rheumatoid arthritis. The results of the present study justify a long-term controlled trial to compare oral pulsed dexamethasone treatment (10 mg dexamethasone, once weekly for 4 weeks) with the standard GC regimes in the near future.

Glucocorticoids cause rapid dissociation of a T-cell-receptor-associated protein complex containing LCK and FYN

Although glucocorticoid (GC)-induced nongenomic effects have been reported, the underlying mechanisms remain unexplained. We previously described that lymphocyte-specific protein tyrosine kinase (LCK) and FYN oncogene related to SRC, FGR, YES (FYN) mediate GC-induced inhibition of T-cell-receptor (TCR) signalling. Here we characterize the underlying molecular mechanism. The present study shows that the GC receptor is part of a TCR-linked multiprotein complex containing heat-shock protein (HSP)90, LCK and FYN, which is essential for TCR-dependent LCK/FYN activation. Experiments with cells transfected with GC-receptor short interfering RNA (siRNA) showed that the GC receptor is an essential component of the TCR signalling complex. Short-term GC treatment induces dissociation of this protein complex, resulting in impaired TCR signalling as a consequence of abrogated LCK/FYN activation. HSP90siRNA-transfected cells are not able to assemble this TCR-associated multiprotein complex, and accordingly HSP90siRNA treatment mimics GC effects on LCK/FYN activities. These observations support a model for nongenomic GC-induced immunosuppression on the basis of dissolution of membrane-bound GC-receptor multiprotein complexes after GC-receptor ligation.

Anti-angiogenic effects of liposomal prednisolone phosphate on B16 melanoma in mice

Prednisolone phosphate (PLP) encapsulated in long-circulating liposomes can inhibit tumor growth after intravenous administration (i.v.). These antitumor effects of liposomal PLP are the result of the tumor-targeting property of the liposome formulation. The mechanism by which liposomal PLP inhibits tumor growth is unclear. We investigated the effects of liposome-encapsulated PLP versus free PLP on angiogenic protein production in tumor tissue in vivo and on viability and proliferation of tumor and endothelial cells in vitro. In vivo, liposomal PLP had a stronger reducing effect on pro-angiogenic protein levels than free PLP, whereas levels of anti-angiogenic proteins were hardly affected. Cell viability was only slightly affected with either treatment. Liposomal PLP had strong anti-proliferative effects on human umbilical vein endothelial cells, whereas free PLP had hardly any effect. Taken together, the present study points to a strong inhibitory effect of liposomal PLP on tumor angiogenesis by reduction of the intratumoral production of the majority of pro-angiogenic factors studied and direct inhibition of endothelial cell proliferation, which is the result of high prolonged levels of prednisolone in the tumor by liposomal delivery.