Optimizing glucocorticoid therapy in rheumatoid arthritis

Chronotherapy with low-dose modified-release prednisone for the management of rheumatoid arthritis: a review

To date, rheumatoid arthritis (RA) remains a debilitating, life-threatening disease. One major concern is morning symptoms (MS), as they considerably impair the patients’ quality of life and ability to work. MS change in a circadian fashion, resembling the fluctuations of inflammatory cytokines such as interleukin-6, whose levels are higher in RA patients compared to healthy donors. Conversely, serum levels of the potent anti-inflammatory glucocorticoid cortisol are similar to that of healthy subjects, suggesting an imbalance that sustains a pro-inflammatory state. From a therapeutic point of view, administering synthetic glucocorticoids (GCs) to RA patients represents an optimal strategy to provide for the inadequate levels of cortisol. Indeed, due to their high efficacy in RA, GCs remain a cornerstone more than 60 years after their first introduction, and despite the development of a wide range of targeted agents. However, to improve safety, low-dose GCs have been introduced, that have demonstrated high efficacy in reducing disease activity, radiological progression, and improving patients’ signs and symptoms especially in early RA when added to conventional disease-modifying antirheumatic drugs. A further improvement has been provided by the development of modified-release prednisone, which, by taking advantage of the circadian fluctuations of inflammatory cytokines, cortisol and MS, is given at bedtime to be released approximately 4 hours later. Several studies have already demonstrated the efficacy of this agent on disease activity, MS, and quality of life in the setting of established RA. Moreover, preliminary studies have shown that this new formulation not only has no impact on the adrenal function, but likely improves it. This review is a comprehensive, updated summary of the current evidence on the use of GCs in RA, with focus on the efficacy and safety of low-dose prednisone and modified-release prednisone, the latter representing a rational, cost-effective, and tailored approach to maximize the benefit/risk ratio in RA patients.

Effect of orexin-A (hypocretin-1) on hyperalgesic and cachectic manifestations of experimentally induced rheumatoid arthritis in rats

Orexin-A has been shown to modulate pain sensation and increase appetite. Rheumatoid arthritis (RA) is characterized by joint destruction, deformity, hyperalgesia, and weight reduction. Aim: Evaluate the possible effect of orexin-A on hyperalgesic and cachectic manifestations in an adjuvant-induced arthritis (AIA) rat model. Methods: Forty adult male Wistar rats were distributed among 4 groups; I, normal controls; II, rats with AIA induced by intradermal injection of Mycobacterium butyricum, but with no other treatment; III, AIA rats treated daily with an intravenous injection of orexin-A for 8 days; and IV, AIA rats treated orally with dexamethasone for 8 days. The parameters we assessed were pain-associated behavior, body mass, hind paw volume, serum levels of nerve growth factor (NGF) and neuropeptide Y (NPY). Results: Orexin-A caused a significant reduction in pain sensation and NGF levels, and increased body mass and the levels of NPY, whereas treatment with dexamethasone led to significant reductions in paw swelling and pain sensation. Conclusion: Orexin-A has hypoalgesic properties and increases body mass, whereas dexamethasone has a potent anti-inflammatory effect. Therefore, the combination of orexin-A and dexamethasone should have a greater effect with respect to attenuating the manifestations and complications associated with RA.

Spinal cord brain-derived neurotrophic factor levels increase after dexamethasone treatment in male rats with chronic inflammation

Dexamethasone is widely used in the therapy of chronic inflammatory diseases for its pain-modulating effects. The objective of this study was to evaluate the effect of dexamethasone on nociception and local inflammation, and the levels of brain-derived neurotrophic factor (BDNF) in the spinal cord in male rats with chronic inflammation induced by complete Freund's adjuvant (CFA). Rats were randomly divided into a control group (not manipulated) and 2 CFA-induced chronic inflammation groups (in the 15th post-CFA injection): 1 injected with vehicle (saline solution) and 1 received dexamethasone (0.25 mg/kg) for 8 days. The hot-plate and electronic von Frey tests were performed 24 h after the end of treatment. BDNF spinal cord levels were determined by enzyme-linked immunosorbent assay (ELISA). The level of inflammation in the tibiotarsal joint (the ankle region) was evaluated histologically at the end of treatment. Dexamethasone produced significantly increased latency in the hot-plate test (one-way ANOVA, p < 0.05) and withdrawal threshold in the electronic von Frey test (p < 0.005). The dexamethasone group showed increased spinal cord BDNF levels compared to the other groups (one-way ANOVA p, < 0.05). Histological analysis showed a local inflammatory response only in animals treated with vehicle, which demonstrated that the dexamethasone treatment decreased the inflammatory process. Our findings corroborate the antinociceptive and anti-inflammatory properties of dexamethasone. In addition, we showed that the dexamethasone treatment increased BDNF levels in the spinal cord; its pain- modulating effects can be attributed to this effect.

Liposomal encapsulation enhances and prolongs the anti-inflammatory effects of water-soluble dexamethasone phosphate in experimental adjuvant arthritis

Introduction

The objective of this study was to evaluate the efficacy of intravenous (i.v.) injection of liposomally encapsulated dexamethasone phosphate (DxM-P) in comparison to free DxM-P in rats with established adjuvant arthritis (AA). This study focused on polyethylene glycol (PEG)-free liposomes, to minimize known allergic reactions caused by neutral PEG-modified (PEG-ylated) liposomes.

Methods

Efficacy was assessed clinically and histologically using standard scores. Non-specific and specific immune parameters were monitored. Activation of peritoneal macrophages was analyzed via cytokine profiling. Pharmacokinetics/biodistribution of DxM in plasma, synovial membrane, spleen and liver were assessed via mass spectrometry.

Results

Liposomal DxM-P (3 × 1 mg/kg body weight; administered intravenously (i.v.) on Days 14, 15 and 16 of AA) suppressed established AA, including histological signs, erythrocyte sedimentation rate, white blood cell count, circulating anti-mycobacterial IgG, and production of interleukin-1beta (IL-1β) and IL-6 by peritoneal macrophages. The suppression was strong and long-lasting. The clinical effects of liposomal DxM-P were dose-dependent for dosages between 0.01 and 1.0 mg/kg. Single administration of 1 mg/kg liposomal DxM-P and 3 × 1 mg/kg of free DxM-P showed comparable effects consisting of a partial and transient suppression. Moreover, the effects of medium-dose liposomal DxM-P (3 × 0.1 mg/kg) were equal (in the short term) or superior (in the long term) to those of high-dose free DxM-P (3 × 1 mg/kg), suggesting a potential dose reduction by a factor between 3 and 10 by liposomal encapsulation. For at least 48 hours after the last injection, the liposomal drug achieved significantly higher levels in plasma, synovial membrane, spleen and liver than the free drug.

Conclusions

This new PEG-free formulation of macrophage-targeting liposomal DxM-P considerably reduces the dose and/or frequency required to treat AA, with a potential to enhance or prolong therapeutic efficacy and limit side-effects also in the therapy of rheumatoid arthritis. Depot and/or recirculation effects in plasma, inflamed joint, liver, and spleen may contribute to this superiority of liposomally encapsulated DxM-P.

The metabolic changes caused by dexamethasone in the adjuvant-induced arthritic rat

The action of orally administered dexamethasone (0.2 mg kg(-1) day(-1)) on metabolic parameters of adjuvant-induced arthritic rats was investigated. The body weight gain and the progression of the disease were also monitored. Dexamethasone was very effective in suppressing the Freund's adjuvant-induced paw edema and the appearance of secondary lesions. In contrast, the body weight loss of dexamethasone-treated arthritic rats was more accentuated than that of untreated arthritic or normal rats treated with dexamethasone, indicating additive harmful effects. The perfused livers from dexamethasone-treated arthritic rats presented high content of glycogen in both fed and fasted conditions, as indicated by the higher rates of glucose release in the absence of exogenous substrate. The metabolization of exogenous L: -alanine was increased in livers from dexamethasone-treated arthritic rats in comparison with untreated arthritic rats, but there was a diversion of carbon flux from glucose to L: -lactate and pyruvate. Plasmatic levels of insulin and glucose were significantly higher in arthritic rats following dexamethasone administration. Most of these changes were also found in livers from normal rats treated with dexamethasone. The observed changes in L: -alanine metabolism and glycogen synthesis indicate that insulin was the dominant hormone in the regulation of the liver glucose metabolism even in the fasting condition. The prevalence of the metabolic effects of dexamethasone over those ones induced by the arthritis disease suggests that dexamethasone administration was able to suppress the mechanisms implicated in the development of the arthritis-induced hepatic metabolic changes. It seems thus plausible to assume that those factors responsible for the inflammatory responses in the paws and for the secondary lesions may be also implicated in the liver metabolic changes, but not in the body weight loss of arthritic rats.

Cellular pharmacodynamics of immunosuppressive drugs for individualized medicine

The therapeutic effects of immunosuppressive drugs are known to deviate largely between patients, but efficient strategies for the differentiation of patients who show clinical resistance to immunosuppressive therapies have not been established. Accordingly, a considerable number of patients receive treatment with immunosuppressive drugs despite the onset of serious side effects and poor responses. Cellular pharmacodynamics of immunosuppressive drugs in vitro using peripheral lymphocytes derived from each patient, an attractive way to distinguish resistant patients, is respected and has been applied to the carrying out of individualized immunosuppressive therapy. In this article, I summarize experimental procedures for assaying immune cell responses to immunosuppressive drugs in vitro, and highlight the relationship between cellular sensitivity to immunosuppressive drugs and the therapeutic efficacy of drugs in organ transplantation and several immunological disorders. I will also overview the molecular mechanisms and genetic bases for cellular and clinical resistance to immunosuppressive drugs. Lastly, the future clinical prospects for the application of in vitro drug sensitivity tests for "patient-tailored" immunosuppressive therapies are discussed.

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.

3D-QSAR and preliminary evaluation of anti-inflammatory activity of series of N-pyrrolylcarboxylic acids

The present study focuses on development of new potential inhibitors of cyclooxygenase-2 (COX-2): series of N-pyrrolylcarboxylic acids. 3D-QSAR (Quantitative Structure-Activity Relationship) CoMFA (Comparative Molecular Field Analysis) and CoMSIA (Comparative Molecular Similarity Index Analysis) models for predicting inhibitory activities against COX-1 and COX-2 as well as for evaluating in vivo anti-inflammatory activity were obtained and used for preliminary screening of new anti-inflammatory N-pyrrolylcarboxylic acids. Nine compounds were selected for in vivo testing and evaluated for their potency to decrease carrageenin-induced edema in rats. The compounds were applied i.p. at doses 20 mg/kg and 40 mg/kg and p.o. at doses 10 mg/kg and 40 mg/kg. Six compounds showed more than 70% protection of the edema. Indomethacin (2 mg/kg i.p.), used as a reference drug, possessed 54% anti-inflammatory activity under similar experimental conditions.

Developments in Glucocorticoid Therapy

Recent evidence for a disease-modifying potential of low-dose glucocorticoids (GCs) in the treatment of rheumatoid arthritis has renewed the debate on the risk benefit ratio with this therapy. Two recent developments are described that might have a positive influence on these risk benefit ratios. One is the improvement in new GC compounds--designer GCs, alterations in bioactivity, and alterations in formulations. The other is a better understanding and management of the toxicity of GCs.

Novel inhibitors of matrix metalloproteinase gene expression as potential therapies for arthritis

Matrix metalloproteinases are a family of endopeptidases that collectively degrade all components of the extracellular matrix at neutral pH. During the progression of arthritis, MMPs mediate the degradation of cartilage, which consists largely of Type II collagen fibrils and proteoglycans. The collagenases, a subgroup of MMPs, have the singular ability to cleave intact collagens and may provide a rate-limiting step in cartilage destruction. In arthritic lesions, collagenase-1 (matrix metalloproteinase-1) and collagenase-3 (matrix metalloproteinase-13) mediate the irreversible destruction of cartilage, suggesting that these enzymes are therapeutic targets. We describe the role of metalloproteinases in the destruction of connective tissues in arthritis and the treatment strategies that have been developed to block matrix metalloproteinases in an attempt to prevent this destruction. We also discuss novel compounds that may selectively inhibit these cartilage-degrading enzymes, providing opportunities to develop new therapeutic approaches.

Corticosteroids induce expression of aquaporin-1 and increase transcellular water transport in rat peritoneum

The water channel aquaporin-1 (AQP1) is the molecular counterpart of the ultrasmall pore responsible for transcellular water permeability during peritoneal dialysis (PD). This water permeability accounts for up to 50% of ultrafiltration (UF) during a hypertonic dwell, and its loss can be a major clinical problem for PD patients. By analogy with the lung, the hypothesis was tested that corticosteroids may increase AQP1 expression in the peritoneal membrane (PM) and improve water permeability and UF in rats. First, the expression and distribution of the glucocorticoid receptor (GR) in the PM and capillary endothelium was documented. Time-course and dose-response analyses showed that a daily IM injection of dexamethasone (1 or 4 mg/kg) for 5 d induced an approximately twofold increase in the expression of AQP1 at the mRNA and protein levels. The GR antagonist RU-486 completely inhibited the dexamethasone effect. The functional counterpart of the increased AQP1 expression was a significant increase in sodium sieving and net UF across the PM, contrasting with a lack of effect on the osmotic gradient and permeability for small solutes. The latter observation reflected the lack of effect of corticosteroids on nitric oxide synthase (NOS) activity and endothelial NOS isoform expression in the PM. In conclusion, corticosteroids induce AQP1 expression in the capillary endothelium of the PM, which is reflected by increased transcellular water permeability and UF. These data emphasize the critical role of AQP1 during PD and suggest that pharmacologic regulation of AQP1 may provide a target for manipulating water permeability across the PM.

Standardised nomenclature for glucocorticoid dosages and glucocorticoid treatment regimens: current questions and tentative answers in rheumatology

In rheumatology and other medical specialties there is a discrepancy between the widespread use and the imprecise designation of glucocorticoid treatment regimens. Verbal descriptions of glucocorticoid treatment regimens used in various phases of diseases vary between countries and institutions. Given this background, a workshop under the auspices of the EULAR Standing Committee on International Clinical Studies including Therapeutic Trials was held to discuss this issue and to seek a consensus on nomenclature for glucocorticoid treatment. This report summarises the panel's discussion and recognises that answers derived from consensus conferences are not definitive. Nevertheless, recommendations on glucocorticoid treatment are presented that (1) reflect current and best knowledge available and (2) take into account current clinical practice. A question-answer rationale presentation style has been chosen to convey the messages, to summarise the meeting in a readable format, and to avoid dogmatism.

Glucocorticoids in rheumatoid arthritis: effects on erosions and bone

Recently, four prospective placebo-controlled studies have further evaluated the disease-modifying properties of glucocorticoids in the treatment of rheumatoid arthritis. These studies irrefutably show that the use of (low) doses of glucocorticoids leads to a significant retardation of the progression of erosions, especially in early rheumatoid arthritis. This effect on erosions seems more impressive and probably more persistent than the well-known relief during low-dose glucocorticoid therapy of symptoms, such as pain, stiffness, and joint scores. The management of the (side) effects of glucocorticoids on bone has clearly improved in the last years. These two developments lead to a further optimizing of glucocorticoid treatment in patients with rheumatoid arthritis.

AUUUA motifs in the 3'UTR of human glucocorticoid receptor alpha and beta mRNA destabilize mRNA and decrease receptor protein expression

An association between a gene polymorphism of the human glucocorticoid receptor (hGR) gene and rheumatoid arthritis has recently been suggested. This polymorphism contains an A to G mutation in the 3'UTR of exon 9beta, which encodes the 3'UTR of the mRNA of the hGRbeta isoform. The hGRbeta isoform can act as a dominant negative inhibitor of hGRalpha, and therefore may contribute to glucocorticoid resistance. The A to G mutation is located in an AUUUA motif, which is known to destabilize mRNA. In the present study, the importance of the mutation in this AUUUA motif was further characterized and mutations in other AUUUA motifs in the 3'UTR of hGRbeta and hGRalpha mRNA were studied. hGRbeta and hGRalpha expression vectors, carrying mutations in one AUUUA motif or all AUUUA motifs were transiently transfected into COS-1 cells. Each transfected vector was analyzed for the mRNA expression level, the mRNA turnover rate and the protein expression level. The naturally occurring mutation in the 3'UTR of hGRbeta mRNA increased mRNA stability and protein expression. Mutation of two other AUUUA motifs in the 3'UTR of hGRbeta, or mutation of all four AUUUA motifs resulted in a similar effect. Mutation of the most 5' AUUUA motif did not alter hGRbeta mRNA expression or mRNA stability. Mutation of all 10 AUUUA motifs in the 3'UTR of hGRalpha mRNA increased hGRalpha mRNA expression and mRNA stability as well as expression of the receptor protein level. Thus, the naturally occurring mutation in an AUUUA motif in the 3'UTR of hGRbeta mRNA results not only in increased mRNA stability, but also in increased receptor protein expression, which may contribute to glucocorticoid resistance. A similar role is suggested for two other AUUUA motifs in the 3'UTR of hGRbeta mRNA and for the 10 AUUUA motifs that are present in the 3'UTR of hGRalpha.

Neuroendocrine immune mechanisms in rheumatic diseases. An overview and future implications

A new physiopathogenetic paradigm may be proposed for RA and possibly its related systemic rheumatic diseases (i.e., mechanisms whereby multiple risk factors initially perturb the homeostasis of core physiologic components over an extended premorbid phase, which may progress to clinical disease in later decompensated stages). These complex interactive processes are likely to be individualized according to genetic, nongenomic somatic, developmental, behavioral, and environmental influences. Future research promises to further elucidate the roles of neuroendocrine mechanisms in the rheumatic diseases and offers promise for enhanced therapies and possible avenues for disease modification if not eventual prevention.