Circadian rhythms in rheumatoid arthritis: Implications for pathophysiology and therapeutic management

Is it possible to objectively determine morning stiffness in rheumatoid arthritis?

Objectives

This study aimed to objectively and quantitatively exhibit morning stiffness by using electrophysiological methods.

Patients and methods

The prospective, controlled study was conducted with 52 participants between February 2013 and February 2014. Of the participants, 26 were recruited among RA patients (3 males, 23 females; mean age: 55.9±11.2 years; range, 24 to 74 years) followed at the rheumatology clinic, and 26 were healthy subjects (4 males, 22 females; mean age: 54.9±8.3 years; range, 41 to 70 years) for the control group. Duration and severity of morning stiffness were recorded for all participants. Activity of disease and functional status were evaluated by the Disease Activity Score 28 and Health Assessment Questionnaire (HAQ), respectively. Electrophysiological reaction times, severity of pain (Visual Analog Scale), HAQ, and grip strength were measured for each participant twice in 24 h in the morning (08:00-09:00 am) and afternoon (03:00-05:00 pm).

Results

In the RA group, motor reaction and response times and severity of pain values were significantly lower in the afternoon compared to the morning (p=0.030, p=0.031, and p=0.002, respectively), and hand grip strengths were significantly higher in the afternoon (p=0.007). In the control group, no change was observed between morning and afternoon measurements in the strength and reaction time variables.

Conclusion

Our hypothesis that stiffness would slow down the movements in the morning in RA was supported by the prolonged motor and response times in the morning compared to the afternoon. However, in the control group (no morning stiffness), there was no difference in reaction time variables between the morning and afternoon, objectively demonstrating the concept of morning stiffness in this study.

An engineered glove to follow finger function in rheumatoid arthritis: an observational prospective study

The engineered Hand Test System (HTS) glove has shown high reliability in assessing the baseline functional status of rheumatoid arthritis (RA) hand. Starting from this achievement, the aim of the present observational prospective study was to assess the functionality of the single fingers of rheumatoid hand at follow-up. Eighty RA patients performed HTS glove tests at baseline and among these fifty-six patients were re-tested after 7 months. The HTS glove parameters [Touch Duration (TD), Movement Rate (MR), Inter Tapping Interval (ITI)] were correlated with disease activity and disability clinimetric indexes [Disease Activity Score 28 joint count-C-reactive protein (DAS28-CRP), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI), Health Assessment Questionnaire-Disability Index (HAQ-DI), grip strength, visual analogue scale of pain (VAS), patient global assessment (PGA)], and with laboratory values. HTS glove parameters (TD, ITI, and MR) showed statistically significant correlations with clinimetric and clinical indexes at both time points (p < 0.05). During follow-up, a statistically significant variation of all HTS glove parameters for the fingers that have performed both the worst or best HTS test at baseline was detected (p < 0.05), while the mean HTS glove parameter values by considering all fingers did not show a statistically significant variation over time, as well as the traditional clinimetric indexes. Besides the objective role in assessing the RA hand function by integrating the traditional clinimetric indexes, the HTS glove seems a useful tool for evaluating worst or best finger function during time by measuring the movement speed.

Diurnal production of cortisol and prediction of treatment response in rheumatoid arthritis: a 6-month, real-life prospective cohort study

OBJECTIVES

A reduced adrenal reserve-associated cortisol production relative to the enhanced needs of chronic inflammation (disproportion principle) has been observed in rheumatoid arthritis (RA). We examined the possible clinical value of diurnal cortisol measurements in active RA on treatment response prediction.

METHODS

Diurnal cortisol production (measured at: 08-12:00/18:00-22:00) was assessed by electrochemiluminescence immunoassay in 28 consecutive patients with moderately/highly active RA, as well as 3 and 6 months after treatment initiation or/escalation. Twenty-eight COVID-19 patients and 28 age-matched healthy individuals (HC) served as controls.

RESULTS

Saliva diurnal cortisol production in patients with RA was similar to that of HC, despite 12-fold higher serum C reactive protein (CRP) levels, and lower than COVID-19 patients (area under the curve: RA: 87.0±37.6 vs COVID-19: 146.7±14.3, p<0.001), having similarly high CRP. Moreover, a disturbed circadian cortisol rhythm at baseline was evident in 15 of 28 of patients with RA vs 4 of 28 and 20 of 28 of HC and COVID-19 patients, respectively. Treatment-induced minimal disease activity (MDA) at 6 months was achieved by 16 of 28 patients. Despite comparable demographics and clinical characteristics at baseline, non-MDA patients had lower baseline morning cortisol and higher adrenocorticotropic hormone (ACTH) levels compared with patients on MDA (cortisol: 10.9±4.0 vs 18.4±8.2 nmol/L, respectively, p=0.005 and ACTH: 4.8±3.3 vs 2.4±0.4 pmol/L, respectively, p=0.047). Baseline morning cortisol <13.9 nmol/L predicted non-MDA at 6 months (75% sensitivity, 92% specificity, p=0.006). Prospective measurements revealed that individualised diurnal cortisol production remained largely unchanged from baseline to 3 and 6 months.

CONCLUSIONS

An impaired adrenal reserve is present in patients with RA. Further studies to confirm that assessment of diurnal cortisol production may be useful in guiding treatment decisions and/or predicting treatment response in RA are warranted.

TRIAL REGISTRATION NUMBER

NCT05671627.

Treating the Side Effects of Exogenous Glucocorticoids; Can We Separate the Good From the Bad?

It is estimated that 2% to 3% of the population are currently prescribed systemic or topical glucocorticoid treatment. The potent anti-inflammatory action of glucocorticoids to deliver therapeutic benefit is not in doubt. However, the side effects associated with their use, including central weight gain, hypertension, insulin resistance, type 2 diabetes (T2D), and osteoporosis, often collectively termed iatrogenic Cushing's syndrome, are associated with a significant health and economic burden. The precise cellular mechanisms underpinning the differential action of glucocorticoids to drive the desirable and undesirable effects are still not completely understood. Faced with the unmet clinical need to limit glucocorticoid-induced adverse effects alongside ensuring the preservation of anti-inflammatory actions, several strategies have been pursued. The coprescription of existing licensed drugs to treat incident adverse effects can be effective, but data examining the prevention of adverse effects are limited. Novel selective glucocorticoid receptor agonists and selective glucocorticoid receptor modulators have been designed that aim to specifically and selectively activate anti-inflammatory responses based upon their interaction with the glucocorticoid receptor. Several of these compounds are currently in clinical trials to evaluate their efficacy. More recently, strategies exploiting tissue-specific glucocorticoid metabolism through the isoforms of 11β-hydroxysteroid dehydrogenase has shown early potential, although data from clinical trials are limited. The aim of any treatment is to maximize benefit while minimizing risk, and within this review we define the adverse effect profile associated with glucocorticoid use and evaluate current and developing strategies that aim to limit side effects but preserve desirable therapeutic efficacy.

Detecting and exploiting the circadian clock in rheumatoid arthritis

Over the past four decades, research on 24-h rhythms has yielded numerous remarkable findings, revealing their genetic, molecular, and physiological significance for immunity and various diseases. Thus, circadian rhythms are of fundamental importance to mammals, as their disruption and misalignment have been associated with many diseases and the abnormal functioning of many physiological processes. In this article, we provide a brief overview of the molecular regulation of 24-h rhythms, their importance for immunity, the deleterious effects of misalignment, the link between such pathological rhythms and rheumatoid arthritis (RA), and the potential exploitation of chronobiological rhythms for the chronotherapy of inflammatory autoimmune diseases, using RA as an example.

Heat of the night: sleep disturbance activates inflammatory mechanisms and induces pain in rheumatoid arthritis

Sleep has a homeostatic role in the regulation of the immune system and serves to constrain activation of inflammatory signalling and expression of cellular inflammation. In patients with rheumatoid arthritis (RA), a misaligned inflammatory profile induces a dysregulation of sleep-wake activity, which leads to excessive inflammation and the induction of increased sensitivity to pain. Given that multiple biological mechanisms contribute to sleep disturbances (such as insomnia), and that the central nervous system communicates with the innate immune system via neuroendocrine and neural effector pathways, potential exists to develop prevention opportunities to mitigate the risk of insomnia in RA. Furthermore, understanding these risk mechanisms might inform additional insomnia treatment strategies directed towards steering and reducing the magnitude of the inflammatory response, which together could influence outcomes of pain and disease activity in RA.

Neutrophil-to-monocyte ratio is the better new inflammatory marker associated with rheumatoid arthritis activity

Background

Rheumatoid arthritis (RA) is a systemic autoimmune disease that chronically affects patients with episodes of inflammation. New inflammatory hematological markers were investigated for follow-up, such as the neutrophil-monocyte ratio (NMR), lymphocyte monocyte ratio (LMR), and neutrophil-lymphocyte ratio (NLR). This study was conducted to determine the most useful marker based on studies of association with RA disease activity and correlation with the classical markers C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF).

Methods

This case-control study included 62 chronic RA patients who had previously been diagnosed and experienced episodes of symptoms while attending a variety of public and private rheumatology clinics in Ibb City, Republic of Yemen, for the period of September 1 to November 30, 2021. Twenty healthy volunteers were included in this study. Complete blood count, CRP, ESR, and RF levels were measured in all participants.

Results

The total leukocyte count, neutrophil count, platelet count, NMR, LMR, and NLR were positively correlated with CRP and ESR, but the monocyte count was reversed. The area under the curve (AUC = 0.861, 95% confidence interval [CI] = 0.769-0.948) for the NMR cutoff value of 4.7 was equal to that of CRP and close to that of ESR. This NMR cutoff value had 87% sensitivity and 80% specificity. LMR and NLR cutoff values of 4.35 and 1.35, respectively, resulted in AUCs of (AUC = 0.807, 95% CI, 0.708-0.905) and (AUC = 0.699, 95% CI, 0.571-0.819); their sensitivity and specificity were 62.3%, 90%, 57.4%, and 80%, respectively.

Conclusions

As a convenient and low-cost inflammatory marker of RA activity, NMR outperformed LMR and NLR.

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.

The Role of Clock Genes in Maintaining Circadian Rhythm and Rheumatoid Arthritis Pathophysiology

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune condition that affects up to 1% of the world population and symmetrically affects the joints leading to joint stiffness and decreased mobility. RA patients present with increased pain and chronic inflammation within their joint spaces, which researchers have linked to poorer sleep patterns, including difficulty falling asleep and non-restorative sleep. As such, identifying mediators of poor sleep quality among RA patients may improve their long-term quality of life. More recently, researchers identified an association between chronic inflammation in RA patients and their circadian rhythm. Altered circadian rhythms negatively impact the hypothalamic-pituitary-adrenal (HPA) axis and lead to altered cortisol release. Cortisol has shown to have a strong anti-inflammatory effect; when dysregulated, it may lead to increased pain experienced in RA patients. This literature review aims to provide insight into how chronic inflammation tied to RA pathophysiology may affect clock genes that are involved in maintaining the circadian rhythm. Specifically, this review focused on four common clock genes found dysregulated in RA patients: circadian locomotor output cycles kaput (CLOCK), brain and muscle ARNT like-1 (BMAL1), period (PER), and cryptochrome (CRY). Of the four clock genes discussed in this review, BMAL1 and PER are the most well-studied of the affected genes. Further knowledge surrounding clock genes and their dysregulated expression in RA may help guide therapy decisions for RA patients. Traditionally, disease-modifying antirheumatic drugs (DMARDs) have been used as first-line therapy for RA patients. Meanwhile, chronotherapy, optimizing drug release in a timed manner, has shown positive results in RA patients as well. Because of the association of altered circadian rhythms with increased symptom severity in RA patients, it seems highly plausible that DMARD therapy with chronotherapy may be an ideal therapeutic regimen for RA.

The effect of etanercept therapy on adrenal steroid metabolism in juvenile idiopathic arthritis: a steroid metabolomics approach

OBJECTIVE

To evaluate the impact of anti-tumor necrosis factor-alpha (TNFα: etanercept [Etanercept ®]) therapy on adrenal activity in juvenile idiopathic arthritis (JIA) .

METHOD

Eleven JIA patients aged 12 ± 6.2 years with a disease duration of 6.3 ± 5.2 years were enrolled. They were treated once weekly with etanercept (0.8 mg/kg) for 3 ± 2.8 years. Urine samples for gas chromatography-mass spectrometry steroid hormone analysis were collected before, and 1 and 3 days after etanercept injection and compared to age- and sex-matched healthy controls.

RESULTS

The levels of 21 of the 31 metabolites were low before etanercept treatment. Those 21 metabolites included 4 C19 steroids (androgens), 5 C C21 steroid hormone intermediates, 10 cortisol metabolites, and 2 corticosterone metabolites. One day after treatment, only 5 of the 21 metabolite levels remained low. They included 2 C19 metabolites, 2 C21 steroid metabolites and 1 cortisol metabolite β -Cortol (β-Cl). Three days after treatment, the only metabolites levels that continued to be low were 2 C19 metabolite, 2 C21 steroid hormone intermediates and 1 cortisol metabolite α-Cortol (a-Cl), while the remaining 15 metabolites had already normalized after 1 day. Dehydroepiandrosterone-sulfate and 17-hydroxypregnenolone metabolite levels were the last ones to recover. Urinary metabolite ratios reflecting cytochrome P450 CYP21A2 (21-hydroxylase) and 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) enzymatic activitieswere lower in JIA patients than in controls, although significant was not reached.

CONCLUSION

Almost all of the pre-etanercept treatment cortisol urinary metabolite levels were significantly lower than normal, and almost all rose to normal values by 1 day after treatment. The therapeutic effect of anti-TNFα treatment in JIA may be related to its effect on the restoration of adrenal function and cortisol levels.

Association between levels of serotonin, melatonin, cortisol and the clinical condition of patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic connective tissue disease of autoimmune basis. It is characterized by inflammation of joints and systemic complications. The etiopathogenesis is still unknown. Predisposing factors for the disease include genetic, immunological and environmental. Chronic disease and the stress experienced by patients disrupt the body's homeostatic state and weaken the human immune system. Reduced immunity and endocrine disruption may influence the development of autoimmune diseases and exacerbate their course. The aim of the study was to investigate whether there is a relationship between the blood levels of hormones such as cortisol, serotonin, melatonin and the clinical status of RA patients as determined by the DAS28 index and CRP protein. A total of 165 people participated in the study of these 84 subjects had RA and the rest were the control group. All participants completed a questionnaire and had their blood drawn to determine hormones. Patients with RA had higher plasma cortisol (324.6 ng/ml vs. 292.9 ng/ml) and serotonin concentrations (67.9 ng/ml vs. 22.1 ng/ml) and lower plasma melatonin (116.8 pg/ml vs. 330.2 pg/ml) compared to controls. Patients whose CRP concentration were above normal also had elevated plasma cortisol concentration. No significant association was observed in RA patients between plasma melatonin, serotonin and DAS28 values. However, it can be concluded that those with high disease activity had lower melatonin levels as compared to patients with low and moderate DAS28 values. Significant differences were found between RA patients not using steroids and plasma cortisol (p = 0.035). In RA patients, it was observed that as plasma cortisol concentration increased, the chance of having an elevated DAS28 score, indicating high disease activity, increased.

Potential effects of shift work on skin autoimmune diseases

Shift work is associated with systemic chronic inflammation, impaired host and tumor defense and dysregulated immune responses to harmless antigens such as allergens or auto-antigens. Thus, shift workers are at higher risk to develop a systemic autoimmune disease and circadian disruption with sleep impairment seem to be the key underlying mechanisms. Presumably, disturbances of the sleep-wake cycle also drive skin-specific autoimmune diseases, but epidemiological and experimental evidence so far is scarce. This review summarizes the effects of shift work, circadian misalignment, poor sleep, and the effect of potential hormonal mediators such as stress mediators or melatonin on skin barrier functions and on innate and adaptive skin immunity. Human studies as well as animal models were considered. We will also address advantages and potential pitfalls in animal models of shift work, and possible confounders that could drive skin autoimmune diseases in shift workers such as adverse lifestyle habits and psychosocial influences. Finally, we will outline feasible countermeasures that may reduce the risk of systemic and skin autoimmunity in shift workers, as well as treatment options and highlight outstanding questions that should be addressed in future studies.

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.

Circadian stabilization loop: the regulatory hub and therapeutic target promoting circadian resilience and physiological health

The circadian clock is a fundamental biological mechanism that orchestrates essential cellular and physiological processes to optimize fitness and health. The basic functional unit is the cell-autonomous oscillator, consisting of intersecting negative feedback loops. Whereas the core loop is primarily responsible for rhythm generation, auxiliary loops, most notably the secondary or stabilization loop, play pivotal roles to confer temporal precision and molecular robustness. The stabilization loop contains opposing nuclear receptor subfamilies REV-ERBs and retinoic acid receptor-related orphan receptors (RORs), competing to modulate rhythmic expression of the basic helix-loop-helix ARNT like 1 ( Bmal1) genes in the core loop as well as other clock-controlled genes. Therefore, REV-ERBs and RORs are strategically located to interface the oscillator and the global transcriptomic network, promoting cellular homeostasis and physiological fitness throughout lifespan. Disruption of REV-ERB and ROR functions has been linked with diseases and aging, and pharmacological manipulation of these factors has shown promise in various mouse disease models. Nobiletin is a natural compound that directly binds to and activates RORα/γ, modulating circadian rhythms, and shows robust in vivo efficacies to combat clock-associated pathophysiologies and age-related decline. Results from several studies demonstrate an inverse relation between nobiletin efficacy and clock functional state, where nobiletin elicits little effect in young and healthy mice with growing efficacy as the clock is perturbed by environmental and genetic challenges. This mode of action is consistent with the function of the stabilization loop to promote circadian and physiological resilience. Future studies should further investigate the function and mechanism of REV-ERBs and RORs, and test strategies targeting these factors against disease and aging.

Circadian stabilization loop: the regulatory hub and therapeutic target promoting circadian resilience and physiological health

The circadian clock is a fundamental biological mechanism that orchestrates essential cellular and physiological processes to optimize fitness and health. The basic functional unit is the cell-autonomous oscillator, consisting of intersecting negative feedback loops. Whereas the core loop is primarily responsible for rhythm generation, auxiliary loops, most notably the secondary or stabilization loop, play pivotal roles to confer temporal precision and molecular robustness. The stabilization loop contains opposing nuclear receptor subfamilies REV-ERBs and retinoic acid receptor-related orphan receptors (RORs), competing to modulate rhythmic expression of the basic helix-loop-helix ARNT like 1 ( Bmal1) genes in the core loop as well as other clock-controlled genes. Therefore, REV-ERBs and RORs are strategically located to interface the oscillator and the global transcriptomic network, promoting cellular homeostasis and physiological fitness throughout lifespan. Disruption of REV-ERB and ROR functions has been linked with diseases and aging, and pharmacological manipulation of these factors has shown promise in various mouse disease models. Nobiletin is a natural compound that directly binds to and activates RORα/γ, modulating circadian rhythms, and shows robust in vivo efficacies to combat clock-associated pathophysiologies and age-related decline. Results from several studies demonstrate an inverse relation between nobiletin efficacy and clock functional state, where nobiletin elicits little effect in young and healthy mice with growing efficacy as the clock is perturbed by environmental and genetic challenges. This mode of action is consistent with the function of the stabilization loop to promote circadian and physiological resilience. Future studies should further investigate the function and mechanism of REV-ERBs and RORs, and test strategies targeting these factors against disease and aging.

Glucocorticoids and COVID-19

Coronavirus Disease 19 (COVID-19) is associated with high morbidity and mortality rates globally, representing the greatest health and economic challenge today. Several drugs are currently approved for the treatment of COVID-19. Among these, glucocorticoids (GCs) have received particular attention due to their anti-inflammatory and immunosuppressive effects. In fact, GC are widely used in current clinical practice to treat inflammatory, allergic and autoimmune diseases. Major mechanisms of GC action include inhibition of innate and adaptive immune activity. In particular, an important role is played by the inhibition of pro-inflammatory cytokines and chemokines, and the induction of proteins with anti-inflammatory activity. Overall, as indicated by various national and international regulatory agencies, GCs are recommended for the treatment of COVID-19 in patients requiring oxygen therapy, with or without mechanical ventilation. Regarding the use of GCs for the COVID-19 treatment of non-hospitalized patients at an early stage of the disease, many controversial studies have been reported and regulatory agencies have not recommended their use. The decision to start GC therapy should be based not only on the severity of COVID-19 disease, but also on careful considerations of the benefit/risk profile in individual patients, including monitoring of adverse events. In this review we summarize the effects of GCs on the major cellular and molecular components of the inflammatory/immune system, the benefits and the adverse common reactions in the treatment of inflammatory/autoimmune diseases, as well as in the management of COVID-19.

Louis EK, Przybelski SA, Morgenthaler TI, Machulda MM, Boeve BF, Petersen RC, Jack CR, Graff-Radford J, Vemuri P, Mielke MM. Sleepiness in Cognitively Unimpaired Older Adults Is Associated With CSF Biomarkers of Inflammation and Axonal Integrity

Introduction

Sleepiness has been associated with cognitive decline and dementia in the elderly. Older adults with excessive daytime sleepiness appear to be more vulnerable to longitudinal amyloid PET accumulation before the onset of the dementia. However, it remains unclear whether sleepiness is similarly associated with other biomarkers of Alzheimer's disease (AD), axonal integrity, and inflammation, which may also contribute to neurodegeneration and cognitive decline.

Methods

In this cross-sectional analysis, we identified 260 cognitively unimpaired adults (>60 years) from the Mayo Clinic Study of Aging, a population-based cohort from Olmsted County (MN), who underwent CSF quantification of AD biomarkers (Aβ42, p-tau, p-tau/Aβ42) in addition to at least one of the following biomarkers [neurofilament light chain (NfL) interleukin-6 (IL-6), IL-10, and tumor necrosis factor-α (TNF-α)]. We fit linear regression models to assess associations between sleepiness, as measured by the Epworth Sleepiness Scale (ESS), and CSF biomarkers, controlling for age, sex, APOε4 status, body mass index, hypertension, dyslipidemia, and prior diagnosis of obstructive sleep apnea.

Results

Higher ESS scores were associated with higher CSF IL-6 and NfL, but not with the other CSF biomarkers. For every ESS score point increase, there was a 0.009 ([95% CI 0.001-0.016], p = 0.033) increase in the log of IL-6 and 0.01 ([95% CI 0.002-0.018], p = 0.016) increase in the log of NfL. A sensitivity analysis showed an association between ESS scores and log of p-tau/Aβ42 only in participants with an abnormal ratio (>0.023), highly predictive of amyloid positivity. For every ESS score point increase, there was a 0.006 ([95% CI 0.001-0.012], p = 0.021) increase in the log of CSF p-tau/Aβ42.

Conclusion

Sleepiness was associated with greater CSF IL-6 and NfL levels, which could contribute to neurodegeneration or alternatively cause sleepiness. Higher NfL levels may result from sleep disruption and/or contribute to sleepiness via disturbed connectivity or damage to wake-promoting centers. Associations between sleepiness and p-tau/Aβ42 in participants with abnormal ratio suggest that amyloid positivity contributes to vulnerability to sleep disturbance, which may further amyloid accumulation in a feed-forward loop process. Prospective studies of these markers are needed to determine cause-effect relationships between these associations.

Etiology and Risk Factors for Rheumatoid Arthritis: A State-of-the-Art Review

Rheumatoid arthritis (RA) is the most common systemic inflammatory rheumatic disease. It is associated with significant burden at the patient and societal level. Extensive efforts have been devoted to identifying a potential cause for the development of RA. Epidemiological studies have thoroughly investigated the association of several factors with the risk and course of RA. Although a precise etiology remains elusive, the current understanding is that RA is a multifactorial disease, wherein complex interactions between host and environmental factors determine the overall risk of disease susceptibility, persistence and severity. Risk factors related to the host that have been associated with RA development may be divided into genetic; epigenetic; hormonal, reproductive and neuroendocrine; and comorbid host factors. In turn, environmental risk factors include smoking and other airborne exposures; microbiota and infectious agents; diet; and socioeconomic factors. In the present narrative review, aimed at clinicians and researchers in the field of RA, we provide a state-of-the-art overview of the current knowledge on this topic, focusing on recent progresses that have improved our comprehension of disease risk and development.

Chronobiology and Chronotherapy in Inflammatory Joint Diseases

Circadian rhythm perturbations can impact the evolution of different conditions, including autoimmune diseases. This narrative review summarizes the current understanding of circadian biology in inflammatory joint diseases and discusses the potential application of chronotherapy. Proinflammatory cytokines are key players in the development and progression of rheumatoid arthritis (RA), regulating cell survival/apoptosis, differentiation, and proliferation. The production and secretion of inflammatory cytokines show a dependence on the human day–night cycle, resulting in changing cytokine plasma levels over 24 h. Moreover, beyond the circadian rhythm of cytokine secretion, disturbances in timekeeping mechanisms have been proposed in RA. Taking into consideration chronotherapy concepts, modified-release (MR) prednisone tablets have been introduced to counteract the negative effects of night-time peaks of proinflammatory cytokines. Low-dose MR prednisone seems to be able to improve the course of RA, reduce morning stiffness and morning serum levels of IL-6, and induce significant clinical benefits. Additionally, methotrexate (MTX) chronotherapy has been reported to be associated with a significant improvement in RA activity score. Similar effects have been described for polymyalgia rheumatica and gout, although the available literature is still limited. Growing knowledge of chronobiology applied to inflammatory joint diseases could stimulate the development of new drug strategies to treat patients in accordance with biological rhythms and minimize side effects.

The Potential Roles of Dec1 and Dec2 in Periodontal Inflammation

Periodontal inflammation is a common inflammatory disease associated with chronic inflammation that can ultimately lead to alveolar attachment loss and bone destruction. Understanding autophagy and pyroptosis has suggested their significant roles in inflammation. In recent years, studies of differentiated embryo-chondrocyte expressed genes 1 and 2 (Dec1 and Dec2) have shown that they play important functions in autophagy and in pyroptosis, which contribute to the onset of periodontal inflammation. In this review, we summarize recent studies on the roles of clock genes, including Dec1 and Dec2, that are related to periodontal inflammation and other diseases.

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.

Time-of-day effects on the postural control and symptoms in women with rheumatoid arthritis

The present study was designed to assess time-of-day effects on postural balance and symptoms of rheumatoid arthritis (RA) patients. A total of 15 American College of Rheumatology functional class I and II RA patients and 15 healthy controls aged between 45 and 55 (mean age: 50 ± 3) years of age voluntarily participated. We conducted a case-control, repeated-measures in design study. Postural balance, axillary temperature, pain intensity, fatigue, and sleepiness were measured during five test sessions at 06:00, 10:00, 14:00, 18:00, and 22:00 h. Participants were randomized to the order of test sessions, and each session was separated by >36 hours to minimize/eliminate learning effects. Center of pressure area (CoP_area) (p < .001), pain (p < .01), and sleepiness (p < .05) values were significantly higher at 06:00 and 22:00 h compared to 10:00, 14:00, and 18:00 h in the RA group. Fatigue significantly increased (p < .05) at 22:00 h in comparison to 10:00, 14:00, and 18:00 h in the RA group. Axillary temperature was significantly (p < .001) lower at 06:00 and at 22:00 h compared to 10:00, 14:00, and 18:00 h in the RA group. In the control group, there were no significant time-of-day difference in fatigue, but axillary temperature was significantly lower (p < .01) at 06:00 h compared to 10:00 h, 14:00, 18:00, and 22:00 h, sleepiness values were significantly higher (p < .05) at 06:00 and 22:00 h compared to 10:00, 14:00, and 18:00 h, and revealed CoP_area values were significantly (p < .05) higher at 06:00 h compared to 14:00 h. Finally, in the RA group, significant correlations were found between values of CoP_area and pain (r = 0.47; p < .001), sleepiness (r = 0.39; p < .01), fatigue (r = -0.46; p < .001), and also axillary temperature (r = -0.35; p < .001). Multiple linear regression analysis further indicated that in the RA group, time-of-day variation in postural balance was predicted collectively by that in pain and fatigue (30.7%) (R2 = 0.307; F = 11.53; p < .001). Our results first suggest that time-of-day significantly affects postural balance, axillary temperature, pain intensity, fatigue, and sleepiness in RA patients and second that the temporal variation observed in pain, fatigue, and somnolence are concomitant with that observed in postural balance.Abbreviations: RA: Rheumatoid arthritis; H&O questionnaire: Horne and Ostberg questionnaire; PSQI: Pittsburgh sleep quality index; HAQ: Health assessment questionnaire; SF-36: the short form-36; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; CoP: The Center of foot Pressure; CoP_area: The Center of foot Pressure area; VAS: The Visual Analogue Scale; KSS: Karolinska Sleepiness Scale.

Dual Effect of PER2 C111G Polymorphism on Cognitive Functions across Progression from Subjective Cognitive Decline to Mild Cognitive Impairment

BACKGROUND

Periodic circadian protein homolog 2 (PER2) has a role in the intracellular signaling pathways of long-term potentiation and has implications for synaptic plasticity. We aimed to assess the association of PER2 C111G polymorphism with cognitive functions in subjective cognitive decline (SCD).

METHODS

Forty-five SCD patients were included in this study. All participants underwent extensive neuropsychological investigation, analysis of apolipoprotein E (APOE) and PER2 genotypes, and neuropsychological follow-up every 12 or 24 months for a mean time of 9.87 ± 4.38 years.

RESULTS

Nine out of 45 patients (20%) were heterozygous carriers of the PER2 C111G polymorphism (G carriers), while 36 patients (80%) were not carriers of the G allele (G non-carriers). At baseline, G carriers had a higher language composite score compared to G non-carriers. During follow-up, 15 (34.88%) patients progressed to mild cognitive impairment (MCI). In this group, we found a significant interaction between PER2 G allele and follow-up time, as carriers of G allele showed greater worsening of executive function, visual-spatial ability, and language composite scores compared to G non-carriers.

CONCLUSIONS

PER2 C111G polymorphism is associated with better language performance in SCD patients. Nevertheless, as patients progress to MCI, G allele carriers showed a greater worsening in cognitive performance compared to G non-carriers. The effect of PER2 C111G polymorphism depends on the global cognitive status of patients.

Limited utility of novel serological biomarkers in patients newly suspected of having giant cell arteritis

AIM

Diagnosing and monitoring vascular activity in giant cell arteritis (GCA) is difficult due to the paucity of specific serological biomarkers. We assessed the utility of 8 novel biomarkers in an inception cohort of newly suspected GCA patients.

METHOD

Consecutive patients were enrolled between May 2016 and December 2017. Serum was collected within 72 hours of commencing corticosteroids and at 6 months. It was analyzed for levels of intra-cellular adhesion molecule 1, vascular endothelial growth factor (VEGF), pentraxin 3, von Willebrand factor and procalcitonin (5-plex R&D Systems multiplex assay) and interleukin (IL)6, IL12 and interferon-γ (high-sensitivity 3-plex ProcartaPlex multiplex assay). A GCA specific positron emission tomography / computed tomography (PET/CT) scan was performed at enrolment with uptake in each vascular territory graded and summed to derive a total vascular score (TVS).

RESULTS

For the 63 patients enrolled, 12 (19%) had a final diagnosis of biopsy-positive GCA and a further 9 had a clinical diagnosis of biopsy-negative GCA. None of the 8 biomarkers was significantly higher in GCA patients compared with those with alternative diagnoses, or demonstrated a positive correlation with the PET/CT TVS. This was in contrast to the C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) which were higher in the biopsy-positive GCA cohort (P < .04) and showed weak positive correlations with the TVS (correlation coefficient 0.34, P < .01). Procalcitonin did not distinguish between GCA and infection. Concentrations of CRP, ESR, VEGF and pentraxin 3 decreased between diagnosis and 6 months in GCA patients.

CONCLUSION

This study did not identify new serological biomarkers to assist in diagnosing or assessing the vasculitis burden in GCA.

Wechselwirkungen zwischen neuroendokrinem System und Immunsystem bei chronisch-entzündlichen Systemerkrankungen

Hormonelle und neuronale Signalwege können die Manifestation einer chronisch-entzündlichen Systemerkrankung entweder begünstigen oder verhindern. Bei bereits manifester Erkrankung modulieren Hormone und Neurotransmitter den Krankheitsverlauf, in dem sie die Krankheitsaktivität erhöhen oder abschwächen. Beispiele hierfür sind der entzündungshemmende Einfluss der körpereigenen und exogenen Glukokortikoide und die entzündungsfördernden Effekte von Stress bei chronisch-entzündlichen Systemerkrankungen. Bei chronisch-entzündlichen Systemerkrankungen ringt das aktivierte Immunsystem mit dem Gehirn und anderen Organsystemen um Energie, was zu vielfältigen Erkrankungsfolgen und Folgeerkrankungen führt: „sickness behaviour“ mit Fatigue-Symptomatik und depressiven Symptomen, Schlafstörungen, Anorexie, Fehl- und Mangelernährung, Knochenabbau, Muskelabbau und kachektische Fettsucht, Insulinresistenz mit Hyperinsulinämie (begleitet von einer Resistenz gegenüber dem Insulin-like growth factor 1), Dyslipidämie, Veränderungen der Steroidhormonachsen, Störungen der Hypothalamus-Hypophysen-Gonaden-Achse, erhöhter Sympathikotonus, herabgesetzte Aktivität des parasympathischen Nervensystems, arterielle Hypertonie und Volumenbelastung, Entzündungsanämie und zirkadiane Rhythmik der Symptomausprägung. Diese für die Patienten gravierenden Folgeerkrankungen, welche den chronisch-entzündlichen Systemerkrankungen inhärent sind, sollten konsequent therapiert werden.

A Glance at the Use of Glucocorticoids in Rare Inflammatory and Autoimmune Diseases: Still an Indispensable Pharmacological Tool?

Since their discovery, glucocorticoids (GCs) have been used to treat almost all autoimmune and chronic inflammatory diseases, as well as allergies and some forms of malignancies, because of their immunosuppressive and anti-inflammatory effects. Although GCs provide only symptomatic relief and do not eliminate the cause of the pathology, in the majority of treatments, GCs frequently cannot be replaced by other classes of drugs. Consequently, long-term treatments cause adverse effects that may, in turn, lead to new pathologies that sometimes require the withdrawal of GC therapy. Therefore, thus far, researchers have focused their efforts on molecules that have the same efficacy as that of GCs but cause fewer adverse effects. To this end, some GC-induced proteins, such as glucocorticoid-induced leucine zipper (GILZ), have been used as drugs in mouse models of inflammatory pathologies. In this review, we focus on some important but rare autoimmune and chronic inflammatory diseases for which the biomedical research investment in new therapies is less likely. Additionally, we critically evaluate the possibility of treating such diseases with other drugs, either GC-related or unrelated.

Development and Validity Testing of a Morning Stiffness Assessment Scale for Patients with Rheumatoid Arthritis

Morning stiffness is known to exert a significant impact on functional ability, quality of life, and employment status. There is an increasing need for a valid, reliable tool to comprehensively assess morning stiffness. The purpose of this study was to develop and verify a Morning Stiffness Assessment Scale. Items were developed on the basis of a framework of the conceptual attributes of morning stiffness. Validity and reliability tests were conducted on the devised scale. Eighty-five patients with rheumatoid arthritis were included to verify the devised scale. A 10-item Morning Stiffness Assessment Scale was developed. Its content and construct validities were well supported. The scale was found to have good reliability. The devised scale is simple and brief, but it provides a more comprehensive means of evaluation for morning stiffness. We believe this scale offers a clinically useful means of properly assessing morning stiffness and has potential utility for evaluating the effects of morning stiffness treatments.

The Story Behind the Use of Glucocorticoids in the Treatment of Rheumatoid Arthritis

Cortisone was introduced in the treatment of rheumatoid arthritis (RA) in 1948 by Hench and colleagues at the Mayo Clinic which resulted in dramatic improvement of inflammation, function and sense of well-being. It became obvious early on that side effects could develop depending on the dose and duration of use. When cortisone became available in 1950 the practicing physician developed practice patterns without guidance from government agencies, professional organizations or the pharmaceutic industry. The physician did not have guidance about what dose to use or the duration of use, as is available today. In the last 25 years, controlled studies have shown the benefits and safety of low dose prednisone in early RA. The diurnal effect of endogeneous glucocorticoids provides a clue to the timing of a glucocorticoid dose and the duration of the dose is established. The guidelines by the American College of Rheumatology (ACR) particularly but also the European League Against Rheumatism (EULAR) have emphasized side effects and stressed limited use of glucocorticoids in RA. Biologics have been developed and promoted that are used to replace and taper off low dose prednisone. Yet, glucocorticoids used appropriately can be the cornerstone of effective, safe, and inexpensive treatment of early active rheumatoid arthritis.

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.

Glucocorticoids in rheumatoid arthritis: the silent companion in the therapeutic strategy

INTRODUCTION

Glucocorticoids (GCs) are key actors in RA management, despite the increasing number of available drugs. In fact, due to their efficacy and safety, the combination therapy between GCs and conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) is still recommended in the early phase of RA treatment, because improving the long-term results.

AREAS COVERED

In this paper, we reviewed the role of GCs in RA management, focusing on mechanisms of action as well as the benefit/risk ratio of GCs and newer therapeutic formulations. Furthermore, we analyzed GCs DMARDs proprieties on disease activity and their long-term effects on radiographic damage. We designed a narrative review aimed to provide an overview concerning GCs in RA management.

EXPERT OPINION

A large amount of evidence supports the use of GCs in RA, especially in the earliest phases of the disease. Besides GCs symptomatic effects due to their strong anti-inflammatory effects, data from several randomized clinical trials have shown a substantial benefit of low-dose GCs in inhibiting the radiographic damage, thus highlighting GCs DMARDs properties. Besides their recognized role in the treatment of early RA, systematic monitoring of adverse events should be recommended to minimize GCs toxicity.

Effect of Morning vs. Evening Turmeric Consumption on Urine Oxidative Stress Biomarkers in Obese, Middle-Aged Adults: A Feasibility Study

The circadian rhythm of biological systems is an important consideration in developing health interventions. The immune and oxidative defense systems exhibit circadian periodicity, with an anticipatory increase in activity coincident with the onset of the active period. Spice consumption is associated with enhanced oxidative defense. The objective of this study was to test the feasibility of a protocol, comparing the effects of morning vs. evening consumption of turmeric on urine markers of oxidative stress in obese, middle-aged adults. Using a within-sample design, participants received each of four clock time x treatment administrations, each separated by one week: morning turmeric; evening turmeric; morning control; evening control. Participants prepared for each lab visit by consuming a low-antioxidant diet for two days and fasting for 12 h. Urine was collected in the lab at baseline and one-hour post-meal and at home for the following five hours. The results showed that the processes were successful in executing the protocol and collecting the measurements and that participants understood and adhered to the instructions. The findings also revealed that the spice treatment did not elicit the expected antioxidant effect and that the six-hour post-treatment urine collection period did not detect differences in urine endpoints across treatments. This feasibility study revealed that modifications to the spice treatment and urine sampling timeline are needed before implementing a larger study.

Chronotherapy targeting cytokine secretion attenuates collagen-induced arthritis in mice

OBJECTIVE

Diurnal variation of symptoms are observed in rheumatoid arthritis, especially in productions of cytokines that show peak concentrations during mid night. In contrast, cytokines of collagen-induced arthritis (CIA) mice increase in daytimes under Mid-light condition. By using chronotherapy, differences in drug efficacies according to administration time of Baricitinib, a wide ranged cytokine blocker, were examined in CIA mice.

METHODS

CIA mice were administered a dose of 3 mg/kg of Baricitinib once a day at zeitgeber time (ZT) 0 or ZT12 for 21 days. Arthritis scores, histopathology and factors related to joint destruction in sera were examined. Phosphorylation of STAT3 in liver, expressions of cytokines in spleen, and Interleukin (IL)-6 and tumor necrosis factor (TNF)-α in sera were measured.

RESULTS

In CIA mice, diurnal variations were observed both in expressions of cytokines and phosphorylation of STAT3. Arthritis scores of ZT0/12 group decreased from day3 as compared to untreated mice, and those of ZT0 group significantly decreased as compared to ZT12 group from day12. Pathological findings, immunohistochemistry of cytokines and Receptor activator of nuclear factor kappa-Β ligand (RANKL)/osteoprotegerin ratio in sera well reflected results of arthritis scores. Diurnal variation of STAT3 phosphorylation was suppressed in ZT0 group. At ZT2, expressions of IL-6/Interferon-γ/TNF/granulocyte-macrophage colony-stimulating factor in ZT0 group were significantly decreased as compared to untreated mice, though not in ZT12 group. In ZT0 group, IL-6 and TNF-α in sera were decreased for longer time than that in ZT12 group.

CONCLUSION

Chronotherapy using Baricitinib targeting cytokine secretions is effective in CIA mice. Clinical applications of chronotherapy can be expected to enhance the drug efficacy.

Contribution of tenosynovitis of small joints to the symptom morning stiffness in patients presenting with undifferentiated and rheumatoid arthritis

Objective: Morning stiffness (MS) is characteristic of rheumatoid arthritis (RA). Despite its association with functional disability, the extent to which local inflammatory processes contribute to this symptom is unknown. Magnetic resonance imaging (MRI)-detected tenosynovitis of small joints is recognized as an early feature of RA, which is also associated with functional impairments. It has been proposed that tenosynovitis contributes to MS. Therefore, we assessed the relationship between MS and MRI-detected inflammation, in particular tenosynovitis.Method: In total, 286 consecutive patients newly presenting with undifferentiated arthritis and RA underwent contrast-enhanced 1.5 T MRI of (2-5) metacarpophalangeal, wrist, and (1-5) metatarsophalangeal joints. Scans were scored for tenosynovitis according to Haavardsholm, and for synovitis by Rheumatoid Arthritis Magnetic Resonance Imaging Scoring (RAMRIS). MS was dichotomized as ≥ 60 min or not. Associations between MS and tenosynovitis/synovitis were tested with logistic regression, data were categorized (solitary or simultaneous presence of synovitis/tenosynovitis), and the presence of an additive interaction was assessed.Results: MS was present in 40% of patients. Tenosynovitis was more often present in patients with MS than without MS [80% vs 65%, odds ratio (OR) 2.11, 95% confidence interval (1.21;3.69)]. Synovitis was more often present in patients with MS [58% vs 44%, OR 1.79 (1.11;2.91)]. In categorized analyses, concurrent synovitis and tenosynovitis had the largest association [OR 2.43 (1.30;4.54)], in contrast to solitary synovitis [OR 0.85 (0.21;3.47)]. The additive interaction was non-significant. The variance explained in all analyses was small (range 4-5%).Conclusion: Tenosynovitis, combined with synovitis, at small joints is associated with MS and contributes to the pathophysiology of MS.

Targeting REV-ERBα for therapeutic purposes: promises and challenges

REV-ERBα (NR1D1) is a circadian clock component that functions as a transcriptional repressor. Due to its role in direct modulation of metabolic genes, REV-ERBα is regarded as an integrator of cell metabolism with circadian clock. Accordingly, REV-ERBα is first proposed as a drug target for treating sleep disorders and metabolic syndromes (e.g., dyslipidaemia, hyperglycaemia and obesity). Recent years of studies uncover a rather broad role of REV-ERBα in pathological conditions including local inflammatory diseases, heart failure and cancers. Moreover, REV-ERBα is involved in regulation of circadian drug metabolism that has implications in chronopharmacology. In the meantime, recent years have witnessed discovery of an array of new REV-ERBα ligands most of which have pharmacological activities in vivo. In this article, we review the regulatory role of REV-ERBα in various types of diseases and discuss the underlying mechanisms. We also describe the newly discovered ligands and the old ones together with their targeting potential. Despite well-established pharmacological effects of REV-ERBα ligands in animals (preclinical studies), no progress has been made regarding their translation to clinical trials. This implies certain challenges associated with drug development of REV-ERBα ligands. In particular, we discuss the potential challenges related to drug safety (or adverse effects) and bioavailability. For new drug development, it is advocated that REV-ERBα should be targeted to treat local diseases and a targeting drug should be locally distributed, avoiding the adverse effects on other tissues.

Role of methotrexate chronotherapy in collagen-induced rheumatoid arthritis in rats

Aim

To explore the circadian rhythm of serum interleukin (IL)-6 in collagen-induced arthritis (CIA) rats and compare the safety and effectiveness of methotrexate (MTX) administered traditionally and via chronotherapy.

Methods

CIA rat models were immunized with bovine type II collagen. Serum IL-6 levels in normal and CIA rats were measured at 2, 6, 10, 14, 18, or 22 h after the light was turned on (HALO). MTX was administered to 6 HALO/18 HALO experimental groups of Wistar rats once daily according to the IL-6 rhythm. The control groups (positive, negative, and normal) were given MTX or an equal volume of phosphate buffered saline (PBS) once a week simultaneously. Arthritis score, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and C reactive protein (CRP) levels in the serum were measured by enzyme-linked immunosorbent assay (ELISA). Histological changes in the ankle joint were analyzed.

Results

After 6 weeks of treatment, arthritis scores in the experimental group were lower than in the control group. The expression of TNF-α, IL-6, and CRP was lower in the 18 HALO group than in the control or 6 HALO groups. Histopathology scores in the experimental groups were lower than in the control group (p < 0.05).

Conclusion

The plasma IL-6 levels in CIA rats were higher than in normal rats and showed significant circadian rhythm. Daily administration of MTX is more potent than weekly administration. The therapeutic index of rheumatoid arthritis (RA) may be improved with MTX therapy based on the IL-6 circadian rhythm.

Correlation of fatigue with other disease related and psychosocial factors in patients with rheumatoid arthritis treated with tocilizumab: ACT-AXIS study

To assess the hypothesis if tocilizumab (TCZ) is effective on disease activity, and also its effect in fatigue and other clinical and psychological disease-related factors in patients with rheumatoid arthritis (RA) treated with TCZ.A 24-week, multicenter, prospective, observational study in patients with moderate to severe RA receiving TCZ after failure or intolerance to disease-modifying antirheumatic drugs or tumor necrosis factor-alpha was conducted.Of the 122 patients included, 85 were evaluable for effectiveness (85% female, 51.9 ± 12.5 years, disease duration 8.7 ± 7.4 years). Mean change in C-reactive protein level from baseline to week 12 was -11.2 ± 4.0 (P < .001). Mean Disease Activity Index score (DAS28) decreased from 5.5 ± 1.0 at baseline to 2.7 ± 1.3 (P < .001) at week 24. Mean change in Functional Assessment of Chronic Illness Therapy score was -5.4 ± 11.2 points at week 24. Multiple regression analysis showed that the improvement in DAS28, sleep, and depression explained 56% and 47% of fatigue variance at week 12 and 24, respectively.Tocilizumab is effective in reducing disease activity and results in a clinically significant improvement in fatigue, pain, swollen joint count, morning stiffness, sleepiness, depression, and DAS28; the last 3 were specifically identified as factors explaining fatigue variance with the use of TCZ in RA patients.

Determination of the minimally important difference (MID) in multi-biomarker disease activity (MBDA) test scores: impact of diurnal and daily biomarker variation patterns on MBDA scores

The Multi-Biomarker Disease Activity (MBDA) score is a validated rheumatoid arthritis (RA) disease activity measure based on 12 serum biomarkers. Here, we evaluate short-term biological variability of MBDA scores to determine the magnitude of change that might be considered clinically meaningful. Twenty-eight adult seropositive RA patients with clinically stable disease and no changes in RA medications for 4 weeks prior to study were enrolled. Nine serum samples were obtained over four consecutive days (non-fasting). MBDA score variation was assessed day-to-day (daily) and within 24 h (diurnal). The standard deviation (SD) of MBDA scores was calculated by a linear mixed model including random effects for patient, day, and time of day. The minimally important difference (MID) was calculated as [Formula: see text]. A subgroup analysis was performed for patients with active RA (moderate or high MBDA score). The SD of MBDA score change in the full cohort was 4.7 in a combined daily-diurnal variation analysis, which corresponds with an MID of 11. The SD of MBDA score change in the subset of patients with active RA (moderate/high MBDA scores) was 3.6. This corresponds with an MID of 8 units in patients with active RA for whom clinicians are most likely to need guidance with respect to therapeutic decisions. Changes in MBDA score ≥ 8 represent a change in RA disease activity that clinicians can use as a benchmark for therapeutic drug efficacy and can be incorporated into a treat-to-target strategy.

Expert Recommendations on the Interleukin 6 Blockade in Patients with Rheumatoid Arthritis

OBJECTIVE

To draft recommendations on interleukin 6 (IL-6) blockade in rheumatoid arthritis (RA), based on best evidence and experience.

METHODS

A group of 10 experts on IL-6 blockade in RA was selected. The 2 coordinators formulated 23 questions about IL-6 blockade (indications, efficacy, safety, etc.). A systematic review was conducted to answer the questions. Using this information, inclusion and exclusion criteria were established, as were the search strategies (Medline, EMBASE and the Cochrane Library were searched). Two different reviewers selected the articles. Evidence tables were created. At the same time, European League Against Rheumatism and American College of Rheumatology abstracts were evaluated. Based on this evidence, the coordinators proposed preliminary recommendations that the experts discussed and voted on in a nominal group meeting. The level of evidence and grade of recommendation were established using the Oxford Centre for Evidence Based Medicine and the level of agreement with the Delphi technique (2 rounds). Agreement was established if at least 80% of the experts voted yes (yes/no).

RESULTS

The 8 preliminary recommendations were accepted after the Delphi process. They covered aspects such as the use of these therapies in monotherapy, in combination, in patients with refractory disease or intolerant patients, response evaluation, optimization and risk management.

CONCLUSIONS

The manuscript aims to solve frequently asked questions and aid in decision making strategies when treating RA patients with IL-6 blockade.

Morning Stiffness in Elderly Patients with Rheumatoid Arthritis: What is Known About the Effect of Biological and Targeted Agents?

Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects all age groups, but the prevalence appears to increase with age. Elderly-onset RA (after the age of 60 years) has distinct clinical patterns. Treatment of RA in older individuals is confounded by the presence of medical comorbidities, concurrent medications, drug interactions, and the altered pharmacokinetics and pharmacodynamics related to aging and organ dysfunction. Patients with RA commonly experience morning stiffness, which is associated with reduced quality of life and work disability. However, despite its importance, morning stiffness is seldom assessed in clinical practice and usually only its duration is measured in the research setting. Whether the intensity, timing, location and impact of this symptom should be assessed in future clinical trials requires further evaluation. The biologic and newer targeted synthetic disease-modifying anti-rheumatic drugs have been shown to be effective in reducing the duration of morning stiffness in patients with RA. Glucocorticoids are a double-edged sword in RA. Although they can effectively reduce inflammation and retard radiological damage (disease modifying), the long-term use of glucocorticoids is associated with numerous adverse effects. Thus, glucocorticoids should be used for short-term treatment of RA only. Night-time administration of glucocorticoids has been shown to alleviate morning stiffness and should be considered in patients with serious morning joint stiffness symptoms.

The 70th anniversary of glucocorticoids in rheumatic diseases: the second youth of an old friend

Seventy years ago, the first administration of cortisone in a patient with RA marked a milestone in the treatment of inflammatory diseases. However, the initial enthusiasm rapidly vanished as the administration of high doses for lengthy periods revealed worrisome adverse effects. It has taken several decades to overcome the (sometimes excessive) mistrust and to achieve a more differentiated evaluation of the benefit–risk profile and the adequate usage of glucocorticoids (GCs). Today, GCs remain indispensable for the treatment of many inflammatory conditions and their usefulness in RA as a disease-modifying low-dose co-medication is widely acknowledged. Recent studies show promising results concerning both traditional GCs and new formulations. Still, decades of relatively little scientific attention have resulted in a continuing lack of detailed evidence. Hence there is an ongoing need for further research regarding mechanisms of GC actions, the further optimization of treatment parameters for traditional GCs and new formulations.

Neurobiological Functions of the Period Circadian Clock 2 Gene, Per2

Most organisms have adapted to a circadian rhythm that follows a roughly 24-hour cycle, which is modulated by both internal (clock-related genes) and external (environment) factors. In such organisms, the central nervous system (CNS) is influenced by the circadian rhythm of individual cells. Furthermore, the period circadian clock 2 (Per2) gene is an important component of the circadian clock, which modulates the circadian rhythm. Per2 is mainly expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus as well as other brain areas, including the midbrain and forebrain. This indicates that Per2 may affect various neurobiological activities such as sleeping, depression, and addiction. In this review, we focus on the neurobiological functions of Per2, which could help to better understand its roles in the CNS.

Heart rate variability testing: could it change spending for rheumatoid arthritis patients in the United States? An exploratory economic analysis

BACKGROUND

Autonomic nervous system (ANS) testing with heart rate variability (HRV) has been shown in early research to predict 52-week outcomes in rheumatoid arthritis (RA). HRV testing could be combined with putative ANS biologic pathways to improve treatment response for RA patients. This study explored potential costs and health outcomes of introducing HRV testing into RA treatment, without and with ANS optimization.

METHODS

A decision tree exploratory economic model compared HRV testing to standard care in moderate-to-severe biologic-eligible patients over a 10-year time horizon. HRV data was derived from an observational study of RA patients (n = 33). Patients were stratified into treatment groups based on HRV test scores indicating "low probability of response" and "moderate to high probability of response". This study explored adding ANS optimization based on HRV score followed by clinically-appropriate treatment. Costs and quality-adjusted life-years (QALYs) for the US population were estimated.

RESULTS

HRV testing in biologic-eligible patients decreased non-effective biologic use, reducing US healthcare costs by $34.6 billion over 10 years with QALYs unchanged. When combined with ANS optimization in biologic-eligible patients, HRV testing could increase costs by $3.6 billion over 10 years but save over 350,000 QALYs. Among all RA patients, HRV testing with ANS optimization could save over $8 billion and over 100,000 QALYs over 10 years, depending on the positive predictive value (PPV) of the HRV test.

CONCLUSIONS

The potential economic impact of introducing HRV testing and ANS optimization into RA treatment appears substantial and cost-effective based on the exploratory analysis. Additional rigorous studies are warranted in larger patient samples to better inform decision-making.

Development and testing of candidate items for inclusion in a new rheumatoid arthritis stiffness patient-reported outcome measure

Objective

To qualitatively develop and test a set of candidate items for a new RA stiffness patient-reported outcome measure (PROM) that capture the patient perspective. This is an essential first step in PROM development, prior to quantitative development, assessment and validation.

Methods

Focus groups further examined the previously developed stiffness conceptual model and explored the patient perspective regarding stiffness assessment. Data were analysed using thematic analysis. An iterative process of item development was then performed by the expert study team of researchers, patients and clinicians, based on the two qualitative datasets and informed by measurement theory and guidelines. Finally, these candidate items were tested using formal cognitive interview methodology and subsequently refined.

Results

Sixteen RA patients from the UK participated in focus groups. Data confirmed the conceptual model of the RA patient experience of stiffness and provided insight into stiffness assessment, including suggestions regarding patient-relevant stiffness assessment categories such as impact, location and timing. These data informed the development of 77 candidate stiffness PROM items, including multiple formats for some. Eleven RA patients participated in cognitive interviews. Minor changes were made to items to enhance understanding and 32 items were removed, resulting in 45 candidate PROM items.

Conclusion

Rigorous qualitative methodology and considerable patient involvement has underpinned items for a new RA stiffness PROM with strong content validity. Crucially, patient involvement broadened assessment beyond early morning stiffness duration, which may address existing PROM limitations. Items are now suitable for quantitative item reduction, structural development of the final PROM and validation.

Modeling the Influence of Seasonal Differences in the HPA Axis on Synchronization of the Circadian Clock and Cell Cycle

Synchronization of biological functions to environmental signals enables organisms to anticipate and appropriately respond to daily external fluctuations and is critical to the maintenance of homeostasis. Misalignment of circadian rhythms with environmental cues is associated with adverse health outcomes. Cortisol, the downstream effector of hypothalamic-pituitary-adrenal (HPA) activity, facilitates synchronization of peripheral biological processes to the environment. Cortisol levels exhibit substantial seasonal rhythmicity, with peak levels occurring during the short-photoperiod winter months and reduced levels occurring in the long-photoperiod summer season. Seasonal changes in cortisol secretion could therefore alter its entraining capabilities, resulting in a season-dependent modification in the alignment of biological activities with the environment. We develop a mathematical model to investigate the influence of photoperiod-induced seasonal differences in the circadian rhythmicity of the HPA axis on the synchronization of the peripheral circadian clock and cell cycle in a heterogeneous cell population. Model simulations predict that the high-amplitude cortisol rhythms in winter result in the greatest entrainment of peripheral oscillators. Furthermore, simulations predict a circadian gating of the cell cycle with respect to the expression of peripheral clock genes. Seasonal differences in cortisol rhythmicity are also predicted to influence mitotic synchrony, with a high-amplitude winter rhythm resulting in the greatest synchrony and a shift in timing of the cell cycle phases, relative to summer. Our results highlight the primary interactions among the HPA axis, the peripheral circadian clock, and the cell cycle and thereby provide an improved understanding of the implications of circadian misalignment on the synchronization of peripheral regulatory processes.

Methotrexate upregulates circadian transcriptional factors PAR bZIP to induce apoptosis on rheumatoid arthritis synovial fibroblasts

Background

Effects of methotrexate (MTX) on the proliferation of rheumatoid arthritis (RA) synovial fibroblasts are incompletely understood. We explored actions of MTX in view of circadian transcriptions of synovial fibroblasts.

Methods

Under treatment with MTX, expression of core circadian clock genes, circadian transcriptional factor proline and acidic amino acid-rich basic leucine zipper (PAR bZIP), and proapoptotic molecule Bcl-2 interacting killer (Bik) was examined by real-time polymerase chain reaction. Protein expression of circadian clock gene PERIOD2 (PER2) and CYTOCHROME C was also examined by western blotting and ELISA. Promoter activities of Per2 and Bik were measured by Luciferase assay. Expression of PER2, BIK, and CYTOCHROME C and morphological changes of the nucleus were observed by fluorescent immunostaining. Synovial fibroblasts were transfected with Per2/Bik small interfering RNA, and successively treated with MTX to determine cell viabilities. Finally, synovial fibroblasts were treated with MTX according to the oscillation of Per2/Bik expression.

Results

MTX (10 nM) significantly decreased cell viabilities, but increased messenger RNA expression of Per2, Bik, and PAR ZIP including D site of the albumin promoter binding protein (Dbp), hepatic leukemia factor (Hlf), and thyrotroph embryonic factor (Tef). MTX also increased protein expression of PER2 and CYTOCHROME C, and promoter activities of Per2 and Bik via D-box. Under fluorescent observations, expression of PER2, BIK, and CYTOCHROME C was increased in apoptotic cells. Cytotoxicity of MTX was attenuated by silencing of Per2 and/or Bik, and revealed that MTX was significantly effective in situations where Per2/Bik expression was high.

Conclusions

We present here novel unique action of MTX on synovial fibroblasts that upregulates PAR bZIP to transcribe Per2 and Bik, resulting in apoptosis induction. MTX is important in modulating circadian environments to understand a new aspect of pathogenesis of RA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1552-9) contains supplementary material, which is available to authorized users.

Asymmetry in Signal Oscillations Contributes to Efficiency of Periodic Systems

Oscillations are an important feature of cellular signaling that result from complex combinations of positive- and negative-feedback loops. The encoding and decoding mechanisms of oscillations based on amplitude and frequency have been extensively discussed in the literature in the context of intercellular and intracellular signaling. However, the fundamental questions of whether and how oscillatory signals offer any competitive advantages-and, if so, what-have not been fully answered. We investigated established oscillatory mechanisms and designed a study to analyze the oscillatory characteristics of signaling molecules and system output in an effort to answer these questions. Two classic oscillators, Goodwin and PER, were selected as the model systems, and corresponding no-feedback models were created for each oscillator to discover the advantage of oscillating signals. Through simulating the original oscillators and the matching no-feedback models, we show that oscillating systems have the capability to achieve better resource-to-output efficiency, and we identify oscillatory characteristics that lead to improved efficiency.