Glucocorticoids and chronotherapy in rheumatoid arthritis

Quality by design-based development and in vitro evaluation of dual release tablet of etoricoxib and thiocolchicoside: A novel chronotherapeutic approach for arthritis pain management

OBJECTIVE

The traditional drug delivery system is not much effective when treating chronopathological diseases like arthritis. Consequently, there is a gap in the market for a delivery system that can provide an explicit treatment following the chronopharmacology of this disorder. The present study is based on the objective to develop Eudragit coated dual release bilayer tablet designed by the quality by design (QbD) and based on the chronotherapeutic approach. The dual release tablet contained an immediate release layer of etoricoxib and a sustained release layer of thiocolchicoside.

MATERIAL AND METHOD

The quality target product profile (QTTP) of the formulation was established along with critical quality attributes (CQA). The optimization of the dual release layer was done using a three-level, three-factor Box-Behnken design. A total of thirteen formulations of etoricoxib (ET1-ET13) and thiocolchicoside (TH1-TH13) were developed based on the design composition of etoricoxib, sodium starch glycolate and sodium bicarbonate for the immediate release (IR) layer and thiocolchicoside, HPMC E5 LV and magnesium stearate for the sustained release (SR) layer respectively. The developed dual release layers were compressed to form a bilayer tablet. The bilayer tablets were further coated with pH-dependent polymer Eudragit S-100 to avoid drug release in upper GIT. The initial characterization and drug-excipient interaction studies were performed initially using infra-red (IR) spectroscopy and X-ray diffraction studies (XRD). Formulations showing good micrometric properties, disintegration and drug release were selected for final compression of bilayer tablets.

RESULT

Formulation ET13 showed the fastest drug release (88%) at 15minutes and quick disintegration time (21s). The sustained release thiocolchicoside tablet layer (TH1-TH13) had a hardness that varied from 4.01 to 4.45kg/cm2. Formulation TH12 had the highest hardness, whereas TH6 showed the lowest hardness. The sustained release layer showing 97.63% of drug release after 8hours was selected for the compression to bilayer tablet. The developed dual layer tablets were investigated for quality parameters like hardness, percentage friability, weight variation, disintegration and dissolution.

CONCLUSION

A high level of patient compliance is ensured through the current design as the patient does not need to get out of bed at night to take the medication.

Daily glucocorticoids promote glioblastoma growth and circadian synchrony to the host

Glioblastoma (GBM) is the most common primary brain tumor in adults with a poor prognosis despite aggressive therapy. A recent, retrospective clinical study found that administering Temozolomide in the morning increased patient overall survival by 6 months compared to evening. Here, we tested the hypothesis that daily host signaling regulates tumor growth and synchronizes circadian rhythms in GBM. We found daily Dexamethasone promoted or suppressed GBM growth depending on time of day of administration and on the clock gene, Bmal1. Blocking circadian signals, like VIP or glucocorticoids, dramatically slowed GBM growth and disease progression. Finally, mouse and human GBM models have intrinsic circadian rhythms in clock gene expression in vitro and in vivo that entrain to the host through glucocorticoid signaling, regardless of tumor type or host immune status. We conclude that GBM entrains to the circadian circuit of the brain, which modulates its growth through clockcontrolled cues, like glucocorticoids.

Circadian Regulation of Endocrine Fibroblast Growth Factors on Systemic Energy Metabolism

The circadian clock is an endogenous biochemical timing system that coordinates the physiology and behavior of organisms to earth's ∼24-hour circadian day/night cycle. The central circadian clock synchronized by environmental cues hierarchically entrains peripheral clocks throughout the body. The circadian system modulates a wide variety of metabolic signaling pathways to maintain whole-body metabolic homeostasis in mammals under changing environmental conditions. Endocrine fibroblast growth factors (FGFs), namely FGF15/19, FGF21, and FGF23, play an important role in regulating systemic metabolism of bile acids, lipids, glucose, proteins, and minerals. Recent evidence indicates that endocrine FGFs function as nutrient sensors that mediate multifactorial interactions between peripheral clocks and energy homeostasis by regulating the expression of metabolic enzymes and hormones. Circadian disruption induced by environmental stressors or genetic ablation is associated with metabolic dysfunction and diurnal disturbances in FGF signaling pathways that contribute to the pathogenesis of metabolic diseases. Time-restricted feeding strengthens the circadian pattern of metabolic signals to improve metabolic health and prevent against metabolic diseases. Chronotherapy, the strategic timing of medication administration to maximize beneficial effects and minimize toxic effects, can provide novel insights into linking biologic rhythms to drug metabolism and toxicity within the therapeutical regimens of diseases. Here we review the circadian regulation of endocrine FGF signaling in whole-body metabolism and the potential effect of circadian dysfunction on the pathogenesis and development of metabolic diseases. We also discuss the potential of chrononutrition and chronotherapy for informing the development of timing interventions with endocrine FGFs to optimize whole-body metabolism in humans. SIGNIFICANCE STATEMENT: The circadian timing system governs physiological, metabolic, and behavioral functions in living organisms. The endocrine fibroblast growth factor (FGF) family (FGF15/19, FGF21, and FGF23) plays an important role in regulating energy and mineral metabolism. Endocrine FGFs function as nutrient sensors that mediate multifactorial interactions between circadian clocks and metabolic homeostasis. Chronic disruption of circadian rhythms increases the risk of metabolic diseases. Chronological interventions such as chrononutrition and chronotherapy provide insights into linking biological rhythms to disease prevention and treatment.

The Physiological and Pharmacological Significance of the Circadian Timing of the HPA Axis: A Mathematical Modeling Approach

As a potent endogenous regulator of homeostasis, the circadian time-keeping system synchronizes internal physiology to periodic changes in the external environment to enhance survival. Adapting endogenous rhythms to the external time is accomplished hierarchically with the central pacemaker located in the suprachiasmatic nucleus (SCN) signaling the hypothalamus-pituitary-adrenal (HPA) axis to release hormones, notably cortisol, which help maintain the body's circadian rhythm. Given the essential role of HPA-releasing hormones in regulating physiological functions, including immune response, cell cycle, and energy metabolism, their daily variation is critical for the proper function of the circadian timing system. In this review, we focus on cortisol and key fundamental properties of the HPA axis and highlight their importance in controlling circadian dynamics. We demonstrate how systems-driven, mathematical modeling of the HPA axis complements experimental findings, enhances our understanding of complex physiological systems, helps predict potential mechanisms of action, and elucidates the consequences of circadian disruption. Finally, we outline the implications of circadian regulation in the context of personalized chronotherapy. Focusing on the chrono-pharmacology of synthetic glucocorticoids, we review the challenges and opportunities associated with moving toward personalized therapies that capitalize on circadian rhythms.

Circadian Modulation of the Antioxidant Effect of Grape Consumption: A Randomized Controlled Trial

Grape consumption acts on the immune system to produce antioxidant and anti-inflammatory effects. Since immune activity demonstrates circadian rhythmicity, with peak activity occurring during waking hours, the timing of grape intake may influence the magnitude of its antioxidant effect. This study followed a 2 × 2 factorial randomized, controlled design wherein healthy men and women (n = 32) consumed either a grape or placebo drink with a high-fat meal in the morning or evening. Urine was collected for measurements of biomarkers of oxidative stress and grape metabolites at baseline and post-meal at hour 1 and hours 1-6. F-2 isoprostane levels showed main effects of time period (baseline < hour 1 < hours 1-6, p < 0.0001), time (a.m. > p.m., p = 0.008) and treatment (placebo > grape, p = 0.05). Total F2-isoprostane excretion expressed as % baseline was higher in the a.m. vs. p.m. (p = 0.004) and in the a.m. placebo vs. all other groups (p < 0.05). Tartaric acid and resveratrol excretion levels were higher in the grape vs. placebo group (p < 0.05) but were not correlated with F-2 isoprostane levels. The findings support a protective effect of grape consumption against morning sensitivity to oxidative stress.

Circadian Regulation of Macrophages and Osteoclasts in Rheumatoid Arthritis

Rheumatoid arthritis (RA) represents one of the best examples of circadian fluctuations in disease severity. Patients with RA experience stiffness, pain, and swelling in afflicted joints in the early morning, which tends to become milder toward the afternoon. This has been primarily explained by the higher blood levels of pro-inflammatory hormones and cytokines, such as melatonin, TNFα, IL-1, and IL-6, in the early morning than in the afternoon as well as insufficient levels of anti-inflammatory cortisol, which rises later in the morning. Clinical importance of the circadian regulation of RA symptoms has been demonstrated by the effectiveness of time-of-day-dependent delivery of therapeutic agents in chronotherapy. The primary inflammatory site in RA is the synovium, where increased macrophages, T cells, and synovial fibroblasts play central roles by secreting pro-inflammatory cytokines, chemokines, and enzymes to stimulate each other, additional immune cells, and osteoclasts, ultimately leading to cartilage and bone erosion. Among these central players, macrophages have been one of the prime targets for the study of the link between circadian rhythms and inflammatory activities. Gene knockout experiments of various core circadian regulators have established that disruption of any core circadian regulators results in hyper- or hypoactivation of inflammatory responses by macrophages when challenged by lipopolysaccharide and bacteria. Although these stimulations are not directly linked to RA etiology, these findings serve as a foundation for further study by providing proof of principle. On the other hand, circadian regulation of osteoclasts, downstream effectors of macrophages, remain under-explored. Nonetheless, circadian expression of the inducers of osteoclastogenesis, such as TNFα, IL-1, and IL-6, as well as the knockout phenotypes of circadian regulators in osteoclasts suggest the significance of the circadian control of osteoclast activity in the pathogenesis of RA. More detailed mechanistic understanding of the circadian regulation of macrophages and osteoclasts in the afflicted joints could add novel local therapeutic options for RA.

Perspectives of colon-specific drug delivery in the management of morning symptoms of rheumatoid arthritis

Rheumatoid arthritis is a chronic condition that is characterized by joint pain and inflammation. It is an autoimmune disorder in which the body tissues are erroneously attacked by the immune system of the host itself. It has been evident that rheumatoid arthritis symptoms follow a 24 h circadian rhythm and exhibit high thresholds of pain, functional disability, and stiffness predominantly early in the morning. Colon-specific drug delivery systems can be utilized in the formulations to be used in the treatment of rheumatoid arthritis. The colon-specific drug delivery system has shown promising results in the treatment of different diseases at the colonic site like Crohn's disease, ulcerative colitis, colon cancer, etc. The colon-specific drug delivery is capable of delivering the formulation at the predetermined location and predetermined time. The early morning symptoms of rheumatoid arthritis like pain and inflammation can be treated using the various approaches of the colon-specific drug delivery system because it will lead to patient compliance as the patient will not require administering the formulation immediately after waking up in the morning. This review also explains the immunological factors which may trigger rheumatoid arthritis in human beings. It further explores conventional approaches like pH-dependant, microorganisms-driven, pressure-controlled, and time-dependant formulations. By employing two or more conventional approaches given above the various novel approaches have been designed to eliminate the drawbacks of individual techniques.

Impact of Chronotherapy on 6-Mercaptopurine Metabolites in Inflammatory Bowel Disease: A Pilot Crossover Trial

INTRODUCTION

Chronotherapy is the timing of medication according to biological rhythms of the host to optimize drug efficacy and minimize toxicity. Efficacy and myelosuppression of azathioprine/6-mercaptopurine (AZA/6-MP) are correlated with the metabolite 6-thioguanine, while the metabolite 6-methylmercaptopurine correlates with hepatotoxicity.

METHODS

This was a single-center, 10-week prospective crossover trial involving 26 participants with inactive inflammatory bowel disease (IBD) on a stable dose and time of AZA or 6-MP therapy. Participants were switched to the opposite delivery time (morning or evening) for 10 weeks, and metabolite measurements were at both time points.

RESULTS

In the morning vs evening dosing, 6-thioguanine levels were 225.7 ± 155.1 vs 175.0 ± 106.9 ( P < 0.01), and 6-methylmercaptopurine levels were 825.1 ± 1,023.3 vs 2,395.3 ± 2,880.3 ( P < 0.01), with 69% (18 out of 26) of participants had better metabolite profiles in the morning. Participants with optimal dosing in the morning had an earlier chronotype by corrected midpoint of sleep.

DISCUSSION

In the first study on a potential role of chronotherapy in IBD, we found (i) morning dosing of AZA or 6-MP resulted in more optimal metabolite profiles and (ii) host chronotype could help identify one-third of patients who would benefit from evening dosing. Circadian regulation of metabolic enzymes of AZA/6-MP activity in the liver is the likely cause of these differences. This pilot study confirms the need to incorporate chronotherapy in future multicenter clinical trials on IBD disease.

Circadian pain patterns in human pain conditions - A systematic review

BACKGROUND

Chronobiology is the science of how physiological processes in the body follow a pattern of time. Pain has been shown to follow a circadian rhythm, with different types of pain having variable expression along this rhythm.

OBJECTIVE

This article reviews the nature of diurnal variations in pain along with a discussion of the mechanisms of circadian rhythm of pain.

EVIDENCE REVIEW

We conducted a literature search on the PubMed and Google Scholar electronic databases, through April 2022. Publications were screened for English language, full-text availability, and human subjects. Randomized controlled trials and observational trials were included. Data were extracted from studies on patients with acute or chronic pain phenotypes, which provide pain severity data and corresponding diurnal time points.

FINDINGS

The literature search led to the inclusion of 39 studies. A circadian pattern of pain was found to be present in nociceptive, neuropathic, central, and mixed pain states. Postoperative pain, fibromyalgia, trigeminal neuralgia, and migraines were associated with higher pain scores in the morning. Temporomandibular joint pain, neuropathic pain, labor pain, biliary colic, and cluster headaches increased throughout the day to reach a peak in the evening or night. Arthritis and cancer pain were not associated with any circadian rhythmicity. Furthermore, the circadian rhythm of pain was not found to be altered in patients on analgesics.

CONCLUSION

The results of this review suggest that an understanding of diurnal variation may help improve therapeutic strategies in pain management, for instance through analgesic titration.

Glucocorticoids in rheumatoid arthritis: Balancing benefits and harm by leveraging the therapeutic window of opportunity

Glucocorticoids have been available since the early 1950s and have since become an integral part of the management of rheumatoid arthritis (RA). Due to their rapid effect, glucocorticoids have an appealing profile for treating flares or as "bridging" agents in early RA. The efficacy of glucocorticoids to treat RA has been well established, both to control disease activity and to delay the progression of joint damage. However, despite their benefits, glucocorticoids have equally well-known adverse effects. It is generally accepted that long-term use of glucocorticoids, particularly at higher doses, is not advisable, and recent guidelines for the management of RA therefore either recommend against the use of glucocorticoids or suggest using them only as bridging therapy. Perceptions on the harmful effects of glucocorticoids remain, although mainly based on observational studies. Prolonged glucocorticoid therapy at low doses is still highly prevalent in clinical practice, but recent data suggest a rather favourable risk-benefit balance for this strategy, even in senior patients. Balancing the benefits and risks of treating RA with glucocorticoids thus remains a somewhat controversial topic. This narrative review outlines the historical and current position of glucocorticoids in the management of RA, while summarising recent evidence on their beneficial and detrimental effects. Furthermore, practical strategies for the current use and tapering of glucocorticoids in RA are formulated.

Circadian rhythms in psoriasis and the potential of chronotherapy in psoriasis management

The physiology and pathology of the skin are influenced by daily oscillations driven by a master clock located in the brain, and peripheral clocks in individual cells. The pathogenesis of psoriasis is circadian-rhythmic, with flares of disease and symptoms such as itch typically being worse in the evening/night-time. Patients with psoriasis have changes in circadian oscillations of blood pressure and heart rate, supporting wider circadian disruption. In addition, shift work, a circadian misalignment challenge, is associated with psoriasis. These features may be due to underlying circadian control of key effector elements known to be relevant in psoriasis such as cell cycle, proliferation, apoptosis and inflammation. Indeed, peripheral clock pathology may lead to hyperproliferation of keratinocytes in the basal layers, insufficient apoptosis of differentiating keratinocytes in psoriatic epidermis, dysregulation of skin-resident and migratory immune cells and modulation of angiogenesis through circadian oscillation of vascular endothelial growth factor A (VEGF-A) in epidermal keratinocytes. Chronotherapeutic effects of topical steroids and topical vitamin D analogues have been reported, suggesting that knowledge of circadian phase may improve the efficacy, and therapeutic index of treatments for psoriasis. In this viewpoint essay, we review the current literature on circadian disruption in psoriasis. We explore the hypothesis that psoriasis is circadian-driven. We also suggest that investigation of the circadian components specific to psoriasis and that the in vitro investigation of circadian regulation of psoriasis will contribute to the development of a novel chronotherapeutic treatment strategy for personalised psoriasis management. We also propose that circadian oscillations of VEGF-A offer an opportunity to enhance the efficacy and tolerability of a novel anti-VEGF-A therapeutic approach, through the timed delivery of anti-VEGF-A drugs.

Identifying hub circadian rhythm biomarkers and immune cell infiltration in rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease with symptoms characterized by typical circadian rhythmic changes. This study aimed to identify the hub circadian rhythm genes (CRGs) in RA and explore their association with immune cell infiltration and pathogenesis of RA.

Methods

The differentially expressed CRGs (DECRGs) between RA and normal control samples were screened from Datasets GSE12021 and GSE55235. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis were used to explore the potential functional mechanisms of DECRGs in RA. Weighted Gene Co-expression Network Analysis and Least Absolute Shrinkage and Selection Operator regression analysis were performed to identify hub CRGs of RA. CIBERSORT was conducted to compare the infiltration level of immune cells in RA and control synovial tissue and their relationship with hub genes. In addition, the diagnostic value of hub biomarkers was evaluated by the area under the receiver operator characteristic curve. Further, a nomogram prediction model was constructed and its significance for clinical decision-making was evaluated.

Results

The green module was identified as the hub module associated with RA. Four hub CRGs (EGR1, FOSL2, GADD45B, and NFIL3) were identified and showed that they had the highest specificity and sensitivity for RA diagnosis, respectively. The expression levels and diagnostic values of these genes were externally validated in the dataset GSE55457. A nomogram prediction model based on the four hub CRGs was constructed and proved to have a certain clinical decision value. Additionally, the correlation analysis of immune cells with hub genes showed that all hub genes were significantly positively correlated with activated mast cells, resting memory CD4+ T cells, and monocytes. Whereas, all hub genes were negatively correlated with plasma cells, CD8+ T cells, and activated memory CD4+ T cells. Meanwhile, FOSL2 and GADD45B were negatively correlated with Tfh cells.

Conclusion

Four hub CRGs were identified and showed excellent diagnostic value for RA. These genes may be involved in the pathological process of RA by disrupting the rhythmic oscillations of cytokines through immune-related pathways and could be considered molecular targets for future chronotherapy against RA.

Chrono-moxibustion adjusts circadian rhythm of CLOCK and BMAL1 in adjuvant-induced arthritic rats

OBJECTIVE

The clinical symptoms of rheumatoid arthritis (RA) have significant circadian rhythms, with morning stiffness and joint pain. Moxibustion is effective in the treatment of RA, while the underlying therapeutic mechanisms remain limited. Thus, we explored whether moxibustion could adjust the circadian rhythm of RA by modulating the core clock genes CLOCK and BMAL1 at the molecular level.

METHODS

144 Sprague Dawley rats were randomly divided into four groups: control group (group A), model group (group B), 7-9 am moxibustion treatment group (group C), and 5-7 pm moxibustion treatment group (group D). Each group was divided into 6 time points (0 am, 4 am, 8 am, 12 N, 6 pm, and 8 pm) with an equal number of rats at each time point. Except for group A, all rats were injected with Freund's Complete Adjuvant (FCA) 0.15 ml on the right foot pad to establish the RA model. The rats of the two moxibustion treatment groups were respectively subjected to moxibustion at 7-9 am and 5-7 pm. After 3 weeks of treatment, the tissues were collected at 6 time points during the next 24 hours. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to test the mRNA expression of CLOCK and BMAL1 in the hypothalamus and synovial tissues. CLOCK and BMAL1 protein expression in synovial tissues were detected with western blot.

RESULTS

Compared to group A, group B showed significantly down-regulated expression levels of CLOCK and BMLA1 at synovial tissue (P < 0.05), while no statistically significant difference was found in the hypothalamus (P > 0.05). The expression levels of CLOCK and BMLA1 were up-regulated in the moxibustion treatment groups in different tissues, especially in synovial tissue (P < 0.05) compared to group B. Nevertheless, no difference was observed between groups C and D (P > 0.05).

CONCLUSIONS

Moxibustion could treat RA by modulating clock core genes CLOCK and BMAL1 to regulate the circadian rhythm. However, there was no significant difference between the 7-9 am moxibustion treatment group and the 5-7 pm moxibustion treatment group. This study provides a basis for research on moxibustion in the treatment of RA.

Circadian rhythm and disease: Relationship, new insights, and future perspectives

The circadian system is responsible for internal functions and regulation of the organism according to environmental cues (zeitgebers). Circadian rhythm dysregulation or chronodisruption has been associated with several diseases, from mental to autoimmune diseases, and with life quality change. Following this, some therapies have been developed to correct circadian misalignments, such as light therapy and chronobiotics. In this manuscript, we describe the circadian-related diseases so far investigated, and studies reporting relevant data on this topic, evidencing this relationship, are included. Despite the actual limitations in published work, there is clear evidence of the correlation between circadian rhythm dysregulation and disease origin/development, and, in this way, clock-related therapies emerge as great progress in the clinical field. Future improvements in such interventions can lead to the development of successful chronotherapy strategies, deeply contributing to enhanced therapeutic outcomes.

Expression Patterns of Clock Gene mRNAs and Clock Proteins in Human Psoriatic Skin Samples

Psoriasis is a systemic inflammatory skin disorder that can be associated with sleep disturbance and negatively influence the daily rhythm. The link between the pathomechanism of psoriasis and the circadian rhythm has been suggested by several previous studies. However, there are insufficient data on altered clock mechanisms in psoriasis to prove these theories. Therefore, we investigated the expression of the core clock genes in human psoriatic lesional and non-lesional skin and in human adult low calcium temperature (HaCaT) keratinocytes after stimulation with pro-inflammatory cytokines. Furthermore, we examined the clock proteins in skin biopsies from psoriatic patients by immunohistochemistry. We found that the clock gene transcripts were elevated in psoriatic lesions, especially in non-lesional psoriatic areas, except for rev-erbα, which was consistently downregulated in the psoriatic samples. In addition, the REV-ERBα protein showed a different epidermal distribution in non-lesional skin than in healthy skin. In cytokine-treated HaCaT cells, changes in the amplitude of the bmal1, cry1, rev-erbα and per1 mRNA oscillation were observed, especially after TNFα stimulation. In conclusion, in our study a perturbation of clock gene transcripts was observed in uninvolved and lesional psoriatic areas compared to healthy skin. These alterations may serve as therapeutic targets and facilitate the development of chronotherapeutic strategies in the future.

The Circadian Clock Protein BMAL1 Acts as a Metabolic Sensor In Macrophages to Control the Production of Pro IL-1β

The transcription factor BMAL1 is a clock protein that generates daily or circadian rhythms in physiological functions including the inflammatory response of macrophages. Intracellular metabolic pathways direct the macrophage inflammatory response, however whether the clock is impacting intracellular metabolism to direct this response is unclear. Specific metabolic reprogramming of macrophages controls the production of the potent pro-inflammatory cytokine IL-1β. We now describe that the macrophage molecular clock, through Bmal1, regulates the uptake of glucose, its flux through glycolysis and the Krebs cycle, including the production of the metabolite succinate to drive Il-1β production. We further demonstrate that BMAL1 modulates the level and localisation of the glycolytic enzyme PKM2, which in turn activates STAT3 to further drive Il-1β mRNA expression. Overall, this work demonstrates that BMAL1 is a key metabolic sensor in macrophages, and its deficiency leads to a metabolic shift of enhanced glycolysis and mitochondrial respiration, leading to a heightened pro-inflammatory state. These data provide insight into the control of macrophage driven inflammation by the molecular clock, and the potential for time-based therapeutics against a range of chronic inflammatory diseases.

Circadian rhythms affect bone reconstruction by regulating bone energy metabolism

Metabolism is one of the most complex cellular biochemical reactions, providing energy and substances for basic activities such as cell growth and proliferation. Early studies have shown that glucose is an important nutrient in osteoblasts. In addition, amino acid metabolism and fat metabolism also play important roles in bone reconstruction. Mammalian circadian clocks regulate the circadian cycles of various physiological functions. In vertebrates, circadian rhythms are mediated by a set of central clock genes: muscle and brain ARNT like-1 (Bmal1), muscle and brain ARNT like-2 (Bmal2), circadian rhythmic motion output cycle stagnates (Clock), cryptochrome 1 (Cry1), cryptochrome2 (Cry2), period 1 (Per1), period 2 (Per2), period 3 (Per3) and neuronal PAS domain protein 2 (Npas2). Negative feedback loops, controlled at both the transcriptional and posttranslational levels, adjust these clock genes in a diurnal manner. According to the results of studies on circadian transcriptomic studies in several tissues, most rhythmic genes are expressed in a tissue-specific manner and are affected by tissue-specific circadian rhythms. The circadian rhythm regulates several activities, including energy metabolism, feeding time, sleeping, and endocrine and immune functions. It has been reported that the circadian rhythms of mammals are closely related to bone metabolism. In this review, we discuss the regulation of the circadian rhythm/circadian clock gene in osteoblasts/osteoclasts and the energy metabolism of bone, and the relationship between circadian rhythm, bone remodeling, and energy metabolism. We also discuss the therapeutic potential of regulating circadian rhythms or changing energy metabolism on bone development/bone regeneration.

Circadian Variation in Efficacy of Medications

Although much has been learned about circadian clocks and rhythms over the past few decades, translation of this foundational science underlying the temporal regulation of physiology and behavior to clinical applications has been slow. Indeed, acceptance of the modern study of circadian rhythms has been blunted because the phenomenology of cyclic changes had to counteract the 20th century dogma of homeostasis in the biological sciences and medicine. We are providing this review of clinical data to highlight the emerging awareness of circadian variation in efficacy of medications for physicians, clinicians, and pharmacists. We are suggesting that gold-standard double-blind clinical studies should be conducted to determine the best time of day for optimal effectiveness of medications; also, we suggest that time of day should be tracked and reported as an important biological variable in ongoing clinical studies hereafter. Furthermore, we emphasize that time of day is, and should be considered, a key biological variable in research design similar to sex. In common with biomedical research data that have been historically strongly skewed toward the male sex, most pharmaceutical data have been skewed toward morning dosing without strong evidence that this is the optimal time of efficacy.

Glucocorticoids in rheumatoid arthritis: current status and future studies

Since their first use for treating rheumatoid arthritis (RA) in the late 1940s, glucocorticoids (GCs) have been representing a substantial part of the therapeutic arsenal for RA. However, even if GCs are still widely prescribed drugs, their toxicity is discussed controversially, so obtaining consensus on their use in RA is difficult. Hence, the most recent European League Against Rheumatism and American College of Rheumatology recommendations on early arthritis and RA management advocate the use of GCs as adjunct treatment to conventional synthetic disease-modifying antirheumatic drugs, at the lowest dose possible and for the shortest time possible. However, the recommendations remain relatively vague on dose regimens and routes of administration. Here, we describe literature data on which the current recommendations are based as well as data from recent trials published since the drafting of the guidelines. Moreover, we make proposals for daily practice and provide suggestions for studies that could help clarifying the place of GCs in RA management. Indeed, numerous items, including the benefit/risk ratio of low-dose and very low-dose GCs and optimal duration of GCs as bridging therapy, remain on the research agenda, and future studies are needed to guide the next recommendations for RA.

Yoga improves mitochondrial health and reduces severity of autoimmune inflammatory arthritis: A randomized controlled trial

BACKGROUND

Oxidative stress (OS) and mitochondrial alterations have been implicated in the pathogenesis of rheumatoid arthritis (RA). Various environmental triggers like air pollutants, smoking, unhealthy social habits and sedentary lifestyle induce OS, which may compromise mitochondrial integrity. This trial was designed to explore the effect of 8-weeks yoga practice on mitochondrial health and disease severity in an active RA group compared with a usual-care control group.

METHODS

A total of 70 subjects were randomized into two groups: yoga group and non-yoga group. Mitochondrial health was assessed by calculation of mitochondrial DNA copy number (mtDNA-CN), OS markers, mitochondrial activity, mitochondrial membrane potential (ΔΨm), circadian rhythm markers and transcripts associated with mitochondrial integrity: AMPK, TIMP-1, KLOTHO, SIRT-1, and TFAM. Parameters of disease activity and disability quotient were also assessed by disease activity score - erythrocyte sedimentation rate (DAS28-ESR) and health assessment questionnaire-disability index (HAQ-DI), respectively.

RESULTS

In yoga group, there was a significant upregulation of mtDNA-CN, mitochondrial activity markers, ΔΨm, and transcripts that maintain mitochondrial integrity after 8-weeks of yoga. There was optimization of OS markers, and circadian rhythm markers post 8-weeks practice of yoga. Yoga group participants showed significant improvements in DAS28-ESR (p < 0.05) and HAQ-DI (p < 0.05) over the non-yoga group.

CONCLUSION

Adoption of yoga by RA patients holds the key to enhance mitochondrial health, improve circadian rhythm markers, OS marker regulation, upregulation of transcripts that maintain mitochondrial integrity, reduce disease activity and its associated consequences on health outcome and hence can be beneficial as an adjunct therapy.

Therapeutics on the clock: Circadian medicine in the treatment of chronic inflammatory diseases

The circadian clock is a collection of endogenous oscillators with a periodicity of ~ 24 h. Recently, our understanding of circadian rhythms and their regulation at genomic and physiologic scales has grown significantly. Knowledge of the circadian influence on biological processes has provided new possibilities for novel pharmacological strategies. Directly targeting the biological clock or its downstream targets, and/or using timing as a variable in drug therapy are now important pharmacological considerations. The circadian machinery mediates many aspects of the inflammatory response and, reciprocally, an inflammatory environment can disrupt circadian rhythms. Therefore, intense interest exists in leveraging circadian biology as a means to treat chronic inflammatory diseases such as sepsis, asthma, rheumatoid arthritis, osteoarthritis, and cardiovascular disease, which all display some type of circadian signature. The purpose of this review is to evaluate the crosstalk between circadian rhythms, inflammatory diseases, and their pharmacological treatment. Evidence suggests that carefully rationalized application of chronotherapy strategies - alone or in combination with small molecule modulators of circadian clock components - can improve efficacy and reduce toxicity, thus warranting further investigation and use.

Role of the Immune System and the Circadian Rhythm in the Pathogenesis of Chronic Pancreatitis: Establishing a Personalized Signature for Improving the Effect of Immunotherapies for Chronic Pancreatitis

Pancreatitis, in both acute and chronic forms, poses a major therapeutic challenge and is associated with great morbidity and several complications. The nature of pancreatic injury in chronic pancreatitis (CP) and the wide range of causative processes that lead to CP have made effective therapy a true unmet need. Multiple physiological, genetic, environmental, and behavioral factors contribute to the development of CP. As a result, several fields of research are aimed at identifying and addressing the factors that contribute to pancreatic injury. In this article, we review the current understanding of the pathogenesis and natural history of CP. We focus on the autonomous nervous system, immune system, and role of a chronobiological therapeutic approach to alleviate symptoms and prevent or reverse pancreatic injury associated with CP. We aim to demonstrate that individualizing chronopharmacological treatments for CP is a promising direction for future treatment using immune, nervous, and circadian systems.

Significant Unresolved Questions and Opportunities for Bioengineering in Understanding and Treating COVID-19 Disease Progression

COVID-19 is a disease that manifests itself in a multitude of ways across a wide range of tissues. Many factors are involved, and though impressive strides have been made in studying this novel disease in a very short time, there is still a great deal that is unknown about how the virus functions. Clinical data has been crucial for providing information on COVID-19 progression and determining risk factors. However, the mechanisms leading to the multi-tissue pathology are yet to be fully established. Although insights from SARS-CoV-1 and MERS-CoV have been valuable, it is clear that SARS-CoV-2 is different and merits its own extensive studies. In this review, we highlight unresolved questions surrounding this virus including the temporal immune dynamics, infection of non-pulmonary tissue, early life exposure, and the role of circadian rhythms. Risk factors such as sex and exposure to pollutants are also explored followed by a discussion of ways in which bioengineering approaches can be employed to help understand COVID-19. The use of sophisticated in vitro models can be employed to interrogate intercellular interactions and also to tease apart effects of the virus itself from the resulting immune response. Additionally, spatiotemporal information can be gleaned from these models to learn more about the dynamics of the virus and COVID-19 progression. Application of advanced tissue and organ system models into COVID-19 research can result in more nuanced insight into the mechanisms underlying this condition and elucidate strategies to combat its effects.

Impact of glucocorticoids on systemic sirtuin 1 expression and activity in rats with adjuvant-induced arthritis

The class III histone deacetylase sirtuin 1 (SIRT1) plays a pivotal role in numerous biological and physiological functions, including inflammation. An association between SIRT1 and proinflammatory cytokines might exist. In addition to their important role in inflammation associated with rheumatoid arthritis (RA), proinflammatory cytokines mediate the development of systemic effects. Here, we evaluated systemic SIRT1 expression and enzymatic activity, in peripheral blood mononuclear cells (PBMCs) and in liver isolated from rats with adjuvant-induced arthritis (AIA), treated or not with low or high doses of glucocorticoids (GCs). We also measured the production of tumour necrosis factor alpha (TNF) and interleukin-1 beta (IL-1 beta) in PBMCs and liver. We found that SIRT1 expression and activity increased in PBMCs of AIA rats compared to healthy controls and decreased under GC treatment. Similarly, we observed an increased SIRT1 activity in the liver of AIA rats compared to healthy controls which decreased under high doses of GCs. We also found an increase in IL-1 beta and TNF levels in the liver of AIA rats compared to healthy controls, which decreased under high doses of GC. We did not observe a significant correlation between SIRT1 activity and proinflammatory cytokine production in PBMC or liver. In contrast, a strong positive correlation was found between the liver levels of TNF and IL-1 beta (rho=0.9503, p=7.5x10^-21). Our results indicate that increased inflammation in AIA rats compared to healthy control is accompanied by an increased SIRT1 activity in both PBMCs and liver, which could be decreased under GC treatment.

Overcoming Compensatory Mechanisms toward Chronic Drug Administration to Ensure Long-Term, Sustainable Beneficial Effects

Chronic administration of drugs leads to the activation of compensatory mechanisms that may inhibit some of their activity and induce unwanted toxicity. These mechanisms are an obstacle for maintaining a sustainable effect for many chronic medications. Pathways that adapt to the burden induced by chronic drugs, whether or not related to the underlying disease, can lead to a partial or complete loss of effect. Variability characterizes many biological systems and manifests itself as large intra- and inter-individual differences in the response to drugs. Circadian rhythm-based chronotherapy is further associated with variability in responses noted among patients. This paper reviews current knowledge regarding the loss of effect of chronic medications and the range of variabilities that have been described in responses and loss of responses. Establishment of a personalized platform for overcoming these prohibitive mechanisms is presented as a model for ensuring long-term sustained medication effects. This novel platform implements personalized variability signatures and individualized circadian rhythms for preventing and opposing the prohibitive effect of the compensatory mechanisms induced by chronic drug administration.

Circadian fluctuations of endothelial nitric oxide synthase activity in females with rheumatoid arthritis: a pilot study

Rheumatoid arthritis (RA) is a disease associated with circadian disorders of steroid hormones or cytokine secretion which induce inflammatory, destructive and proliferative processes in the synovial joints. Angiogenesis plays an important role in RA, but circadian rhythms of the angiogenic mediator production, especially endothelial nitric oxide synthase (NOS3), are still unclear. NOS3 takes part in regulation of endothelial functions, inflammation, and bone remodeling process. Studying circadian rhythms of NOS3 production in RA patients will make an improvement in understanding the angiogenic-inflammatory pathways relevant to rheumatic diseases. The aim of the study was to test the hypothesis of a diurnal variation in circulating levels of NOS3 in RA patients. A cross-sectional monocentric pilot study of circadian variability of endothelial nitric oxide synthase in a Ukrainian population was conducted between March and July 2017. We examined 36 RA patients (100% women) and 34 age-matched healthy women without joint diseases and autoimmune diseases (control). Blood samples were collected four times per day (at 08:00; 14:00; 20:00 and 02:00) for two consecutive days. Serum NOS3 concentration was measured by ELISA (Cloud-Clone Corp kit). The study was conducted in compliance with bioethical standards. The SPSS22 software package was used for statistical processing of the results. A diurnal variation in circulating levels of NOS3 in healthy women was established, with peak values appearing in the evening and acrophase at 20:00, and low values in the morning, with batiphase at 08:00. In patients with RA serum, NOS3 levels were substantially decreased throughout the day compared to the control. In RA patients, a diurnal variation in circulating levels of NOS3 was also established. However, the variability of NOS3 production was higher in RA patients than in the control group. For example, in RA patients the difference between morning/evening values of NOS3 was 1.3 times higher (p < 0.05) than in the control. Negative correlations were found between the morning NOS3 levels and RA activity markers such as DAS28 and the number of tender and swollen joints. The diurnal variation in circulating levels of NOS3 in women with RA as well as in healthy women was found. However, in RA patients, a decrease in NOS3 production was observed, especially in the morning, which was associated with an increase in the disease activity. Thus, the circadian rhythm of circulating NOS3 can be opposite to the circadian rhythm of secretion of main inflammatory regulators in RA.

Circadian Rhythms of Endothelial Nitric Oxide Synthase and Toll-like Receptors 2 Production in Females with Rheumatoid Arthritis Depending on NOS3 Gene Polymorphism

BACKGROUND

Rheumatoid Arthritis (RA) is an autoimmune polygenic disease characterized by rapid disability progression and high prevalence. Progression of RA is closely associated with chronobiological changes in the production of some hormones and inflammatory mediators, influencing the disease course and therapy efficacy. The main pathogenetic mechanism of RA is angiogenesis, which is controlled by biological clock-genes. Further investigation of circadian rhythms of angiogenic mediators production in RA patients may be considered as important and relevant. The aim of this study was to establish daily variability of serum endothelial Nitric Oxide Synthase (NOS3) and toll-like receptors 2 (sTLR2) levels in female RA patients depending on the NOS3 gene polymorphism.

METHODS

We examined 173 RA patients (100% female) aged 43.7 ± 7.35 years and 34 age-matched healthy women without joint diseases and autoimmune diseases (control). RA was diagnosed by ACR/EULAR 2010 criteria. Blood serum NOS3 and sTLR2 levels were determined at 08:00 and 20:00 using Cloud-Clone Corp kits (USA). NOS3 T-786С (rs2070744) polymorphism was determined by Real-Time PCR (Bio-Rad iCycler IQ5) using SNP-express kits. The SPSS22 software package was used for statistical processing of the results.

RESULTS

Females with RA demonstrated oppositely directed serum NOS3 and sTLR2 daily changes: NOS3 level in the morning (08:00) was lower than in the evening (+ 45.5 ± 30.7%), and sTLR2 level in the evening (at 20:00) was lower than in the morning (-21.6 ± 13.1%). RA patients had differences in NOS3 and sTLR2 production depending on NOS3 T786C genotype. CC subjects had NOS3 level at 08:00, 20:00 and day average levels lower (16-25%), and sTLR2 level higher (24-27%) than those of TT subjects. RA patients, carriers of CC genotype, had higher chances of NOS3 and sTLR2 aberrant production compared to TT and TC genotype carriers (OR = 2.99 and 4.79, respectively).

CONCLUSION

RA patients demonstrated oppositely directed circadian changes of serum NOS3 and sTLR2. CC genotype carriers had lower NOS3 and higher sTLR2 production rates than TT and TC genotype carriers.

Modeling inter-sex and inter-individual variability in response to chronopharmacological administration of synthetic glucocorticoids

Endogenous glucocorticoids have diverse physiological effects and are important regulators of metabolism, immunity, cardiovascular function, musculoskeletal health and central nervous system activity. Synthetic glucocorticoids have received widespread attention for their potent anti-inflammatory activity and have become an important class of drugs used to augment endogenous glucocorticoid activity for the treatment of a host of chronic inflammatory conditions. Chronic use of synthetic glucocorticoids is associated with a number of adverse effects as a result of the persistent dysregulation of glucocorticoid sensitive pathways. A failure to consider the pronounced circadian rhythmicity of endogenous glucocorticoids can result in either supraphysiological glucocorticoid exposure or severe suppression of endogenous glucocorticoid secretion, and is thought be a causal factor in the incidence of adverse effects during chronic glucocorticoid therapy. Furthermore, given that synthetic glucocorticoids have potent feedback effects on the hypothalamic-pituitary-adrenal (HPA) axis, physiological factors which can give rise to individual variability in HPA axis activity such as sex, age, and disease state might also have substantial implications for therapy. We use a semi-mechanistic mathematical model of the rodent HPA axis to study how putative sex differences and individual variability in HPA axis regulation can influence the effects of long-term synthetic exposure on endogenous glucocorticoid circadian rhythms. Model simulations suggest that for the same drug exposure, simulated females exhibit less endogenous suppression than males considering differences in adrenal sensitivity and negative feedback to the hypothalamus and pituitary. Simulations reveal that homeostatic regulatory variability and chronic stress-induced regulatory adaptations in the HPA axis network can result in substantial differences in the effects of synthetic exposure on the circadian rhythm of endogenous glucocorticoids. In general, our results provide insight into how the dosage and exposure profile of synthetic glucocorticoids could be manipulated in a personalized manner to preserve the circadian dynamics of endogenous glucocorticoids during chronic therapy, thus potentially minimizing the incidence of adverse effects associated with long-term use of glucocorticoids.

Chronopharmacology of glucocorticoids

Glucocorticoids influence a wide array of metabolic, anti-inflammatory, immunosuppressive, and cognitive signaling processes, playing an important role in homeostasis and preservation of normal organ function. Synthesis is regulated by the hypothalamic-pituitary-adrenal (HPA) axis of which cortisol is the primary glucocorticoid in humans. Synthetic glucocorticoids are important pharmacological agents that augment the anti-inflammatory and immunosuppressive properties of endogenous cortisol and are widely used for the treatment of asthma, Crohn's disease, and rheumatoid arthritis, amongst other chronic conditions. The homeostatic activity of cortisol is disrupted by the administration of synthetic glucocorticoids and so there is interest in developing treatment options that minimize HPA axis disturbance while maintaining the pharmacological effects. Studies suggest that optimizing drug administration time can achieve this goal. The present review provides an overview of endogenous glucocorticoid activity and recent advances in treatment options that have further improved patient safety and efficacy with an emphasis on chronopharmacology.

Prednisone may rebuild the immunologic homeostasis: Alteration of Th17 and Treg cells in the lymphocytes from rats' spleens after treated with prednisone-containing serum

Background

This study aimed to investigate alterations of T helper 17 (Th17), regulatory T (Treg) cells and relative cytokines after treating with prednisone‐contained serum. Lymphocytes were isolated from female rats' spleens.

Methods

The splenic lymphocytes were divided into four groups: which were treated with normal rats' serum (control); prednisone‐containing rats' serum (PDN); normal rats' serum and cytokines (CTK); cytokines and prednisone‐containing rats' serum (PDN + CTK). The mRNA expression level of RORC, Foxp3 and interleukin‐17 (IL‐17) was examined by reverse transcription‐polymerase chain reaction. The quantities of Th17 and Treg cells were tested by flow cytometry, and the concentrations of IL‐17 and IL‐10 were detected by enzyme‐linked immunosorbent assay.

Results

Higher mRNA expression level of Foxp3, percentages of Treg/CD4⁺, and concentrations of IL‐10, lower mRNA expressions of RORC and IL‐17, concentrations of IL‐17 and percentages of Th17/CD4⁺ in PDN group were detected, compared with control group (all p < 0.01). Similar trend was detected in PDN + CTK group, compared with CTK group (all p < 0.01).

Conclusion

Our results suggest that prednisone may rebuild the immunologic homeostasis and may be used in human diseases with changes in the imbalance immune system such as unexplained recurrent spontaneous abortion (URSA), hepatitis B infection, or other autoimmune diseases.

Modeling the influence of chronopharmacological administration of synthetic glucocorticoids on the hypothalamic-pituitary-adrenal axis

Natural glucocorticoids, a class of cholesterol-derived hormones, modulate an array of metabolic, anti-inflammatory, immunosuppressive and cognitive signaling. The synthesis of natural glucocorticoids, largely cortisol in humans, is regulated by the hypothalamic-pituitary-adrenal (HPA) axis and exhibits pronounced circadian variation. Considering the central regulatory function of endogenous glucocorticoids, maintenance of the circadian activity of the HPA axis is essential to host survival and chronic disruption of such activity leads to systemic complications. There is a great deal of interest in synthetic glucocorticoids due to the immunosuppressive and anti-inflammatory properties and the development of novel dosing regimens that can minimize the disruption of endogenous activity, while still maintaining the pharmacological benefits of long-term synthetic glucocorticoid therapy. Synthetic glucocorticoids are associated with an increased risk of developing the pathological disorders related to chronic suppression of cortisol rhythmicity as a result of the potent negative feedback by synthetic glucocorticoids on the HPA axis precursors. In this study, a mathematical model was developed to explore the influence of chronopharmacological dosing of exogenous glucocorticoids on the endogenous cortisol rhythm considering intra-venous and oral dosing. Chronic daily dosing resulted in modification of the circadian rhythmicity of endogenous cortisol with the amplitude and acrophase of the altered rhythm dependent on the administration time. Simulations revealed that the circadian features of the endogenous cortisol rhythm can be preserved by proper timing of administration. The response following a single dose was not indicative of the response following long-term, repeated chronopharmacological dosing of synthetic glucocorticoids. Furthermore, simulations revealed the inductive influence of long-term treatment was only associated with low to moderate doses, while high doses generally led to suppression of endogenous activity regardless of the chronopharmacological dose. Finally, chronic daily dosing was found to alter the responsiveness of the HPA axis, such that a decrease in the amplitude of the cortisol rhythm resulted in a partial loss in the time-of-day dependent response to CRH stimulation, while an increase in the amplitude was associated with a more pronounced time-of-day dependence of the response.

Circadian rhythms and rheumatoid arthritis

Circadian rhythms (Nobel prize for Medicine 2017) regulate, under action of biological clocks located both at the level of central nervous system and inside peripheral cells, several daily activities, embracing sleep, feeding times, energy metabolism, endocrine and immune functions with related pathological conditions, including rheumatoid arthritis (RA). In RA the circadian rhythms impact on cellular functions, involving night synthesis and release of pro-inflammatory cytokines and chemokines, cell migration to inflamed tissues, phagocytosis, proliferative cell response and all are peaking at late night. In chronic inflammatory conditions such as RA, the amplitude of the circadian rhythm of the anti-inflammatory endogenous cortisol availability is not increased as expected and requested, which indicate a reduced night cortisol secretion under the adrenal chronic stress induced by the disease. Therefore, the prevention/treatment of the immune cell night hyperactivity, with related flare of cytokine synthesis and morning RA clinical symptoms, has been shown more effective when the availability of the exogenous glucocorticoids is obtained in the middle of the night (night release). The impressive positive results observed in RA patients treated with modified-night release prednisone with a low-dose chronotherapy, seem applicable even for other agents such as conventional NSAIDs and DMARDs, including the positive experimental and clinical results obtained by the night time daily administration of methotrexate. Interestingly, a very recent study showed that methotrexate upregulates important cell circadian genes, resulting in induction of apoptosis in synovial fibroblasts. The link between the circadian rhythms of the disease and the chronotherapy of RA is promising.

Mapping genes for drug chronotherapy

Genome-wide association studies have been increasingly used to map and characterize genes that contribute to interindividual variation in drug response. Some studies have integrated the pharmacokinetic (PK) and pharmacodynamic (PD) processes of drug reactions into association mapping, gleaning new insight into how genes determine the dynamic relationship of drug effect and drug dose. Here, we present an evolutionary framework by which two distinct concepts, chronopharmacodynamics and heterochrony (describing variation in the timing and rate of developmental events), are married to comprehend the pharmacogenetic architecture of drug response. The resulting new concept, heterochronopharmacodynamics (HCPD), can better interpret how genes influence drug efficacy and drug toxicity according to the circadian rhythm of the body and changes in drug concentration.

Air Travel, Circadian Rhythms/Hormones, and Autoimmunity

Biological rhythms are fundamental for homeostasis and have recently been involved in the regulatory processes of various organs and systems. Circadian cycle proteins and hormones have a direct effect on the inflammatory response and have shown pro- or anti-inflammatory effects in animal models of autoimmune diseases. The cells of the immune system have their own circadian rhythm, and the light-dark cycle directly influences the inflammatory response. On the other hand, patients with autoimmune diseases characteristically have sleep disorders and fatigue, and in certain disease, such as rheumatoid arthritis (RA), a frank periodicity in the signs and symptoms is recognized. The joint symptoms predominate in the morning, and apparently, subjects with RA have relative adrenal insufficiency, with a cortisol peak unable to control the late night load of pro-inflammatory cytokines. Transatlantic flights represent a challenge in the adjustment of biological rhythms, since they imply sleep deprivation, time zone changes, and potential difficulties for drug administration. In patients with autoimmune diseases, the use of DMARDs and prednisone at night is probably best suited to lessen morning symptoms. It is also essential to sleep during the trip to improve adaptation to the new time zone and to avoid, as far as possible, works involving flexible or nocturnal shifts. The study of proteins and hormones related to biological rhythms will demonstrate new pathophysiological pathways of autoimmune diseases, which will emphasize the use of general measures for sleep respect and methods for drug administration at key daily times to optimize their anti-inflammatory and immune modulatory effects.

Circadian control of pain and neuroinflammation

The importance of a neuroinflammatory response to the development and maintenance of inflammatory and neuropathic pain have been highlighted in recent years. Inflammatory cells contributing to this response include circulating immune cells such as monocytes, T and B lymphocytes, and neutrophils, as well as microglia in the central nervous system. Pain signals are transmitted via sensory neurons in the peripheral nervous system, which express various receptors and channels that respond to mediators secreted from these inflammatory cells. Chronobiological rhythms, which include the 24-hr circadian cycle, have recently been shown to regulate both nervous and immune cell activity and function. This review examines the current literature on chronobiological control of neuroinflammatory processes, with a focus on inflammatory and neuropathic pain states. While the majority of this work has stemmed from observational studies in humans, recent advances in using animal models have highlighted distinct mechanisms underlying these interactions. Better understanding interactions between the circadian and neuroimmune systems can help guide the development of new treatments and provide improved care for patients suffering from acute and chronic pain.

Switching From Immediate-Release to Delayed-Release Prednisone in Moderate to Severe Rheumatoid Arthritis: A Practice-Based Clinical Study

Introduction

Rheumatoid arthritis (RA) produces debilitating morning stiffness. Exogenous glucocorticoids can help with these symptoms when timed appropriately. Bedtime dosing of delayed-release prednisone (DR-prednisone) matches the rise of inflammatory cytokines before awakening and can improve stiffness and other RA symptoms. A prospective open-label study was conducted in patients currently on stable doses of immediate-release prednisone (IR-prednisone) who were switched to DR-prednisone to analyze the incremental benefit of better timed and lower dose glucocorticoid therapy.

Methods

Twelve US sites enrolled patients with moderate-severe RA into a 12-week prospective study. Patients were switched from IR- to DR-prednisone while maintaining other existing background therapies. Change from baseline in morning stiffness severity, morning stiffness duration, swollen and tender joint counts (S-TJC), 28 joint disease activity score (DAS28), and patient/physician global assessment (PGA/PhGA), among others, were measured. Post-hoc analyses were performed on those completing 10 weeks of treatment and those with >60 min of morning stiffness at baseline.

Results

Fifty-six patients had at least one follow-up visit and were similar in demographics to previous controlled trials with DR-prednisone with regard to baseline age and DAS28-CRP but had lower morning stiffness and RA duration. DR-prednisone produced a trend toward lower morning stiffness severity and duration with a reduction in daily prednisone dose of almost 1 mg. Patients treated with DR-prednisone for ≥10 weeks demonstrated significant reductions in morning stiffness duration, SJC, TJC, DAS28-CRP, and PhGA (all p ≤ 0.04). Patients treated for ≥10 weeks with >60 min of baseline morning stiffness produced similar results in these measures as well as a 21% reduction in morning stiffness severity (p = 0.02).

Conclusion

Patients switched to DR-prednisone from IR-prednisone in this practice-based study maintained or improved their outcomes across a variety of domains, and results were comparable to previous controlled trials in which patients completed at least 10 weeks of treatment.

Funding

Horizon Pharma USA, Inc.

Trial Registration

ClinicalTrials.gov identifier, NCT02287610.

"Official View" on Glucocorticoids in Rheumatoid Arthritis: A Systematic Review of International Guidelines and Consensus Statements

OBJECTIVE

To describe the perception of the current role of systemic glucocorticoids in the management of rheumatoid arthritis (RA) by examining their importance and the current level of evidence in recent guidelines, and to identify open questions to be addressed in future guidelines and research projects.

METHODS

We conducted a systematic literature review using the databases Ovid Embase, PubMed Medline, and Cochrane Library for guidelines on the pharmacologic treatment of RA. Retrieved articles were evaluated regarding their quality using the Appraisal of Guidelines for Research and Evaluation II tool and scrutinized for all relevant information concerning the use of glucocorticoids.

RESULTS

All guidelines agree that glucocorticoids, especially if given at low doses and for a short duration, are an appropriate option in the treatment of RA. However, many recommendations remain vague, as reliable and detailed evidence is scarce. Important aspects of glucocorticoid therapy are partially or completely neglected, and the existing nomenclature is not used uniformly. Quality evaluation revealed flaws in many articles, concerning not only glucocorticoid-specific recommendations but also guideline quality in general.

CONCLUSION

Current recommendations for use of glucocorticoids in the management of RA are suboptimal. More rigorous evaluation of doses, timing, and duration of their use is needed. Existing nomenclature on glucocorticoid therapy should be used uniformly.

Seven-year tolerability profile of glucocorticoids use in early rheumatoid arthritis: data from the ESPOIR cohort

Objective

To explore the 7-year tolerability profile of glucocorticoids (GC) for early rheumatoid arthritis (RA).

Methods

We examined data for 602 patients with RA from the early arthritis Etude et Suivi des POlyarthrites Indifférenciées Récentes (ESPOIR) cohort (<6 months disease duration) stratified into two groups: with or without GC treatment at least once during follow-up (median 7 years (IQR 0.038–7.65)). The main outcome was a composite of death, cardiovascular disease (including myocardial ischaemia, cerebrovascular accident and heart failure), severe infection and fracture.

Results

Among the 602 patients with RA (476 women (79%), mean age 48±12 years), 386 with GC (64.1%) received low-dose prednisone (mean 3.1±2.9 mg/day for the entire follow-up): 263 started GC during the first 6 months (68%), and the mean duration of total GC treatment was 1057±876 days. As compared with patients without GC (216 (35.9%)), those with GC showed greater use of non-steroidal anti-inflammatory drugs, synthetic and biological disease-modifying antirheumatic drugs and had more active disease disability, higher C reactive protein and anticitrullinated protein antibody levels. Among 65 events (7 deaths, 14 cardiovascular diseases, 19 severe infections and 25 fractures), 44 and 21 occurred in patients with and without GC (p=0.520). Infections were more frequent, although not significantly, in patients with than without GC (p=0.09). On weighted Cox proportional-hazards analysis, with use of propensity score and inverse-probability-of-treatment weighting, and including age, gender, history of hypertension and GC treatment, outcomes did not differ with and without GC (p=0.520; HR=0.889; 95% CI 0.620 to 1.273).

Conclusions

This 7-year analysis of the ESPOIR cohort supports the good safety profile of very low-dose GC for early active RA.

Amelioration of experimental colitis after short-term therapy with glucocorticoid and its relationship to the induction of different regulatory markers

The clinical benefits of short-term therapy with glucocorticoids (GC) in patients with inflammatory bowel disease (IBD) are widely known. However, the effects of this treatment towards the re-establishment of the regulatory network in IBD are not fully explored. We have evaluated the immunological effects of the abbreviated GC therapy in experimental colitis induced by 3% dextran sulphate sodium in C57BL/6 mice. Treatment with GC improved disease outcome, constrained circulating leucocytes and ameliorated intestinal inflammation. The control of the local inflammatory responses involved a reduction in the expression of interferon-γ and interleukin-1β, associated with augmented mRNA levels of peroxisome proliferator-activated receptors (α and γ) in intestine. Furthermore, there was a reduction of CD4⁺ T cells producing interferon-γ, together with an increased frequency of the putative regulatory population of T cells producing interleukin-10, in spleen. These systemic alterations were accompanied by a decrease in the proliferative potential of splenocytes of mice treated in vivo with GC. Notably, treatment with GC also led to an increase in the frequency of the regulatory markers GITR, CTLA-4, PD-1, CD73 and FoxP3, more prominently in spleen. Taken together, our results pointed to a role of GC in the control of leucocyte responsiveness and re-establishment of a regulatory system, which probably contributed to disease control and the restoration of immune balance. Finally, this is the first time that GC treatment was associated with the modulation of a broad number of regulatory markers in an experimental model of colitis.