Impact of filgotinib on pain control in the phase 3 FINCH studies

OBJECTIVE

This post hoc analysis of the FINCH 1-3 (NCT02889796, NCT02873936 and NCT02886728) studies assessed specific effects of filgotinib on pain control and their relationship with other aspects of efficacy in patients with rheumatoid arthritis (RA).

METHODS

Assessments included: residual pain responses of ≤10 and ≤20 mm on a 100 mm visual analogue scale (VAS); the proportion of patients who achieved VAS pain responses in addition to remission or low disease activity by Disease Activity Score-28 with C-reactive protein (DAS28-CRP) or Clinical Disease Activity Index (CDAI) criteria.

RESULTS

Across studies, filgotinib reduced pain from week 2, with responses sustained throughout the studies. In FINCH 1, at week 24, 35.8%, 25.0%, 24.6% and 11.6% of patients in the filgotinib 200 mg, filgotinib 100 mg, adalimumab and placebo arms (each plus methotrexate) achieved VAS pain ≤20 mm in addition to DAS28-CRP remission; 26.3%, 17.9%, 17.2% and 7.6% achieved VAS pain ≤10 mm in addition to DAS28-CRP remission. A similar pattern was seen for CDAI remission. Time during which VAS pain was ≤10 or ≤20 mm was longest with filgotinib 200 mg and comparable between adalimumab and filgotinib 100 mg. Similar findings were reported for filgotinib in FINCH 2 and 3.

CONCLUSION

In all RA populations studied, pain improvements occurred from week 2 and were sustained over time. In FINCH 1, filgotinib 100 mg provided similar pain amelioration to adalimumab, whereas filgotinib 200 mg resulted in greater pain improvement and higher proportion of patients with residual pain ≤10 or ≤20 mm and meeting DAS28-CRP remission criteria.

The relationship between pain and depression and anxiety in patients with inflammatory arthritis: a systematic review protocol

Pain is a major challenge for patients with inflammatory arthritis (IA). Depression and anxiety are common comorbidities in IA, associating with worse outcomes. How they relate to pain is uncertain, with existing systematic reviews (a) mainly considering cross-sectional studies, (b) focusing on the relationship between pain and mental health in the context of disease activity/quality of life, and (c) not specifically considering the impact of treating depression/anxiety on pain. This PROSPERO-registered (CRD42023411823) systematic review will address this knowledge-gap by synthesizing evidence to summarise the associations (and potential mediators) between pain and depression/anxiety and evaluate the impact of treating co-morbid depression/anxiety on pain in IA. Relevant databases will be searched, articles screened and their quality appraised (using Joanna Briggs Institute critical appraisal tools) by two reviewers. Eligible studies will include adults with rheumatoid arthritis or spondyloarthritis, be a clinical trial or observational study, and either (a) report the relationship between pain and depression/anxiety (observational studies/baseline trials), or (b) randomise participants to a pharmacological or psychological treatment to manage depression/anxiety with a pain outcome as an endpoint (trials). To synthesise data on the association between pain and depression/anxiety, where available adjusted coefficients from regression models will be pooled in a random-effects meta-analysis. A synthesis without meta-analysis will summarise mediators. To evaluate the impact of treating depression/anxiety on pain, endpoint mean differences between treatment arms will be combined in a random-effects meta-analysis. Through understanding how depression/anxiety contribute to pain in IA, our review has the potential to help optimise approaches to IA pain.

A concept elicitation study to understand the relationship between sleep and pain in rheumatoid arthritis and axial spondyloarthritis

PURPOSE

This qualitative study (GSK study: 213635) was designed to better understand sleep disturbance as experienced by individuals with rheumatoid arthritis (RA) or axial spondyloarthritis (axSpA), and the relationship between sleep disturbance and pain and other aspects of the disease and disease activity.

METHODS

Sixty-minute, one-on-one, concept elicitation interviews were conducted with 30 participants (15 with RA and 15 with axSpA) from the US. Interviews were audio-recorded and transcribed verbatim. Interview transcripts were coded and analyzed to explore themes related to pain and sleep disturbance, and relationships among those themes.

RESULTS

Pain was a prominent driver of sleep disturbance; 12 participants with RA (80%) and 14 with axSpA (93%) reported that pain impacted their ability to fall asleep, while all 15 with RA (100%) and 14 with axSpA (93%) reported that pain impacted their ability to stay asleep. Two-thirds of participants with RA (67%) or axSpA (60%) described a bi-directional relationship, whereby pain worsened sleep disturbance and sleep disturbance further aggravated pain. Factors other than pain, such as fatigue and emotional health, were also reported as important contributors to sleep disturbance (RA: n = 12/15, 80%; axSpA: n = 14/15, 93%). Participants with RA or axSpA described complex interconnections between fatigue, emotional health, pain, and sleep, often labeling these relationships as "vicious cycles". Notably, half of all participants reported sleep disturbance occurring without pain or other understood causes.

CONCLUSION

These perspectives collected from people with RA or axSpA suggest that reducing sleep disruption directly may offer clinically relevant benefits.

Lipid mediators obtained from docosahexaenoic acid by soybean lipoxygenase attenuate RANKL-induced osteoclast differentiation and rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disease characterized by persistent inflammation and joint destruction. A lipid mediator (LM, namely, 17S-monohydroxy docosahexaenoic acid, resolvin D5, and protectin DX in a ratio of 3:47:50) produced by soybean lipoxygenase from DHA, exhibits anti-inflammatory activity. In this study, we determined the effect of LM on collagen antibody-induced arthritis (CAIA) in mice and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation in RAW264.7 cells. LM effectively downregulated the expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K, inhibited osteoclast formation, and suppressed the NF-κB signaling pathway in vitro. In vivo, LM at 10 μg/kg/day significantly decreased paw swelling and inhibited progression of arthritis in CAIA mice. Moreover, proinflammatory cytokine (tumor necrosis factor-α, interleukin (IL)-6, IL-1β, IL-17, and interferon-γ) levels in serum were decreased, whereas IL-10 levels were increased following LM treatment. Furthermore, LM alleviated joint inflammation, cartilage erosion, and bone destruction in the ankles, which may be related to matrix metalloproteinase and Janus kinase (JAK)-signal transducer and activators of transcription (STAT) signaling pathway. Our findings suggest that LM attenuates arthritis severity, restores serum imbalances, and modifies joint damage. Thus, LM represents a promising therapy for relieving RA symptoms.

A Cross-Sectional Survey of Physicians' Knowledge and Awareness of Chronic Pain Associated with Rheumatoid Arthritis in Rheumatology Departments in Zhejiang Province, China

Objective

To assess physicians' knowledge and awareness of chronic pain associated with rheumatoid arthritis (RA) in Rheumatology departments throughout Zhejiang province to improve chronic pain relief in RA patients.

Methods

A cross-sectional questionnaire survey was conducted onsite and online among rheumatologists in tertiary and secondary hospitals across Zhejiang province, China. The questionnaire inquired about rheumatoid arthritis-related pain cognition, pain assessment, pain management protocols, and medication choice.

Results

Among the 150 questionnaires included, 98 were from tertiary hospitals, and 52 were from secondary hospitals. There was no difference in rheumatologists' perceptions of chronic pain in RA patients between tertiary and secondary hospitals. About 55.1% of rheumatologists from tertiary hospitals and 44.2% of rheumatologists from secondary hospitals utilized unstandardized pain assessment scales. About 46.9% of rheumatologists in tertiary hospitals and 36.5% of rheumatologists in secondary hospitals favored the numerical rating scale (NRS). About 87.8% of rheumatologists in tertiary hospitals and 71.7% of rheumatologists in secondary hospitals conducted pain assessment within 4 hours of admission. About 66.3% of rheumatologists working in tertiary hospitals and 32.7% of rheumatologists practicing in secondary hospitals believed their hospitals had pain departments. For RA patients who complained of pain for the first time, secondarily, or repeatedly, 48%, 26%, and 36.7% of rheumatologists preferred nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and opioid analgesics, respectively. For RA patients with mild, moderate, or severe pain, 74%, 6%, and 16% of rheumatologists preferred NSAIDs, glucocorticoids, and opioid analgesics, respectively.

Conclusion

The assessment and treatment of chronic pain associated with RA are not standardized. For management, more rheumatologists preferred NSAIDs and glucocorticoids.

Flourishing mental health despite disabling chronic pain: Findings from a nationally representative sample of Canadians with arthritis

This study aims to determine the prevalence of, and factors associated with, the "absence of psychiatric disorders" (APD) and "complete mental health" (CMH) among individuals with arthritis who report disabling chronic pain. There are three aspects of CMH: a) APD; b) happiness and/or life satisfaction in the past month on a daily or almost daily basis, and c) high levels of psychological and social well-being. A secondary analysis of a nationally representative sample (n = 620) of individuals with arthritis who report chronic and debilitating pain was conducted. Data were drawn from the Canadian Community Health Survey-Mental Health. The results of this study indicate that many people with arthritis who are living with disabling chronic pain are free of psychiatric disorders (76%) and are in CMH (56%). Factors associated with higher odds of APD and CMH among the sample include having a confidant, being free from insomnia, and having no lifetime history of major depressive disorder and/or generalized anxiety disorder. White respondents were almost 3-fold more likely to be in a state of CMH compared to racialized individuals. Respondents in the top 50% of household incomes were almost 4-fold more likely to be APD compared to the lowest 10%. In conclusion, many individuals with arthritis have excellent mental health despite disabling pain. Clinicians should be attuned to the mental health of their patients, with particular focus on those who may be more vulnerable to adverse mental health outcomes, such as racialized individuals, those in impoverished households, and those who lack social support.

Further evaluation of inflammatory and non-inflammatory aspects of pain in rheumatoid arthritis patients

Objective

A high discrepancy between the number of tender and swollen joints (e.g. ΔTSJ ≥ 7) has previously been used as an indication for the presence of changes in central mechanisms in patients with moderate-to-high disease activity. In this study, we explored whether the ΔTSJ can also be used to obtain insights into the underlying pain mechanisms in patients with on average well-controlled disease activity.

Methods

A 2 year retrospective analysis of routinely obtained 28-joint DAS (DAS28) components was performed on 45 patients with low inflammatory activity at the group level. All patients underwent pressure pain threshold (PPT) and electrical pain threshold (EPT) measurements and completed four self-report questionnaires [short-form 36 (SF-36v2); central sensitization inventory (CSI); generalized pain questionnaire (GPQ); and the pain catastrophizing scale (PCS)].

Results

Patients with a ΔTSJ ≥ 3 at least once in the past 2 years showed significantly lower EPT and PPT values and higher levels of pain and disability on the SF-36v2 compared with the ΔTSJ < 3 group. Furthermore, GPQ scores were significantly higher in those with ΔTSJ ≥ 3, while CSI and PCS scores were similar.

Conclusion

These findings suggest that in patients in the ΔTSJ ≥ 3 group, mechanisms other than inflammation (only) underlie the pain. Moreover, our findings suggest that among the multiple potential underlying psychological mechanisms, pain catastrophizing (as measured by the PCS) and psychological hypervigilance (as measured by the CSI) do not play an important role. These findings could be useful in the clinical management of the patient. Depending on the dominant mechanism underlying the (persistent) pain, patients might respond differently to treatment.

Patient-Physician Communication and Perception of Treatment Goals in Rheumatoid Arthritis: An Online Survey of Patients and Physicians

INTRODUCTION

To evaluate patient-physician communication and patients' understanding of treatment goals in rheumatoid arthritis (RA).

METHODS

A cross-sectional online survey of patients with RA and physicians treating RA was conducted between 16 and 30 June 2021. Participants were asked to rate the importance of 17 goals on a 6-point Likert scale, and mean scores were compared between patients and physicians by the Wilcoxon rank sum test. Patients' satisfaction with physician communication and their understanding of treatment goals were also assessed.

RESULTS

The responses of 502 patients and 216 physicians were analyzed. The most common patient age group was 50-59 years (28.5%), and the mean disease duration was 10.3 years. Physicians had a mean of 19.2 years of treatment experience and were treating a mean of 44.3 patients. Among the 17 goals assessed, patients placed significantly more importance on drug tapering or discontinuation as short-term goals (3-6 months) and on performing basic activities of daily living, being able to engage in daily tasks, achieving and maintaining remission, maintaining better laboratory values, and drug tapering or discontinuation as long-term goals (5-10 years; all adjusted p < 0.05). Patient treatment satisfaction was significantly associated with disease activity, a feeling of treatment effectiveness, satisfaction with physician communication, and agreement with physician goals.

CONCLUSION

Differences exist among patients with RA and physicians treating RA regarding the importance of short- and long-term treatment goals. Good patient-physician communication appears to be important for improving patient satisfaction.

TRIAL REGISTRATION

University Hospital Medical Information Network identifier: UMIN000044463.

Pain in the joints and beyond; the challenge of rheumatoid arthritis

Pain is a common and often debilitating symptom for people living with rheumatoid arthritis. Although pain is a generic feature of inflammation and often improves with successful treatment that targets inflammatory pathways, pain experience can persist. Emerging data suggest that the magnitude of pain relief might vary according to the therapeutic target of pharmacological intervention within the inflammatory cascade. Both inflammatory and non-inflammatory causes contribute to the pain experience, which depends on tissue origin, peripheral sensory mechanisms and their transmission, integration, and interpretation within the nervous system. Contemporary neuroimaging is transforming our understanding of these mechanisms and the role of sensory, emotional, and cognitive contributions to the experience of pain. This understanding paves the way for therapeutic approaches that recognise the existence of multiple, cognitively driven, supraspinal mechanisms for pain modulation and could complement pharmacological inflammation suppression. Such approaches include neuropsychological interventions that have the potential to modify human brain cortical structure and reduce suffering that is often associated with pain experience.

The Biology of Pain: Through the Rheumatology Lens

Chronic pain is a major socioeconomic burden globally. The most frequent origin of chronic pain is musculoskeletal. In inflammatory musculoskeletal diseases such as rheumatoid arthritis (RA), chronic pain is a primary determinant of deleterious quality of life. The pivotal role of peripheral inflammation in the initiation and perpetuation of nociceptive pain is well-established among patients with musculoskeletal diseases. However, the persistence of pain, even after the apparent resolution of peripheral inflammation, alludes to the coexistence of different pain states. Recent advances in neurobiology have highlighted the importance of nociplastic pain mechanisms. In this review we aimed to explore the biology of pain with a particular focus on nociplastic pain in RA.

Mechanisms of chronic pain in inflammatory rheumatism: the role of descending modulation

ABSTRACT

Persistent pain despite satisfactory disease treatment is frequent in rheumatoid arthritis (RA) and spondyloarthritis (Spa) and may result from specific changes in central pain processing. We assessed these mechanisms further by systematically comparing thermal pain thresholds and conditioned pain modulation (CPM) between patients with active RA or Spa and healthy controls. We included 50 patients with RA and 50 patients with Spa and 100 age-matched and sex-matched controls. Heat and cold pain thresholds (HPT-CPT) were measured on the dominant forearm, and CPM was assessed by applying conditioning stimuli (immersion in a cold-water bath) to one foot and the nondominant hand in 2 successive randomized sequences. Descending pain modulation was assessed as the difference in HPTs (in °C) before and after conditioning. Larger HPT differences (ie, a larger CPM effect) reflected more efficient descending inhibition. Potential associations between changes in CPM and clinical data, including disease activity, pain intensity, and psychological and functional variables, were systematically assessed. Heat pain threshold and cold pain threshold were similar in patients and controls. The mean CPM effect was significantly weaker in patients than that in controls for conditioning applied to either the foot (0.25°C ±2.57 vs 2.79°C ±2.31; P < 0.001) or the nondominant hand (0.57°C ±2.74 vs 2.68°C ±2.12; P < 0.001). The smaller CPM effect in patients was correlated with average pain intensity, but not with disease activity or other clinical characteristics, suggesting a significant pathophysiological role for changes in endogenous pain modulation in the mechanisms of chronic pain associated with inflammatory rheumatism.

Role of T CD4+ cells, macrophages, C-low threshold mechanoreceptors and spinal Cav 3.2 channels in inflammation and related pain-like symptoms in murine inflammatory models

BACKGROUND AND PURPOSE

T-type calcium channels, mainly the Ca_v 3.2 subtype, are important contributors to the nociceptive signalling pathway. We investigated their involvement in inflammation and related pain-like symptoms.

EXPERIMENTAL APPROACH

The involvement of Ca_v 3.2 and T-type channels was investigated using genetic and pharmacological inhibition to assess mechanical allodynia/hyperalgesia and oedema development in two murine inflammatory pain models. The location of Ca_v 3.2 channels involved in pain-like symptoms was studied in mice with Ca_v 3.2 knocked out in C-low threshold mechanoreceptors (C-LTMR) and the use of ABT-639, a peripherally restricted T-type channel inhibitor. The anti-oedema effect of Ca_v 3.2 channel inhibition was investigated in chimeric mice with immune cells deleted for Ca_v 3.2. Lymphocytes and macrophages from either green fluorescent protein-targeted Ca_v 3.2 or KO mice were used to determine the expression of Ca_v 3.2 protein and the functional status of the cells.

KEY RESULTS

Ca_v 3.2 channels contributed to the development of pain-like symptoms and oedema in the two murine inflammatory pain models. Our results provided evidence of the involvement of Ca_v 3.2 channels located on C-LTMRs and spinal cord in inflammatory pain. Ca_v 3.2 channels located in T cells and macrophages contribute to the inflammatory process.

CONCLUSION AND IMPLICATIONS

Ca_v 3.2 channels play crucial roles in inflammation and related pain, implying that targeting of Ca_v 3.2 channels with pharmacological agents could be an attractive and readily evaluable strategy in clinical trials, to relieve chronic inflammatory pain in patients.

Mitochondria and sensory processing in inflammatory and neuropathic pain

Rheumatic diseases, such as osteoarthritis and rheumatoid arthritis, affect over 750 million people worldwide and contribute to approximately 40% of chronic pain cases. Inflammation and tissue damage contribute to pain in rheumatic diseases, but pain often persists even when inflammation/damage is resolved. Mechanisms that cause this persistent pain are still unclear. Mitochondria are essential for a myriad of cellular processes and regulate neuronal functions. Mitochondrial dysfunction has been implicated in multiple neurological disorders, but its role in sensory processing and pain in rheumatic diseases is relatively unexplored. This review provides a comprehensive understanding of how mitochondrial dysfunction connects inflammation and damage-associated pathways to neuronal sensitization and persistent pain. To provide an overall framework on how mitochondria control pain, we explored recent evidence in inflammatory and neuropathic pain conditions. Mitochondria have intrinsic quality control mechanisms to prevent functional deficits and cellular damage. We will discuss the link between neuronal activity, mitochondrial dysfunction and chronic pain. Lastly, pharmacological strategies aimed at reestablishing mitochondrial functions or boosting mitochondrial dynamics as therapeutic interventions for chronic pain are discussed. The evidence presented in this review shows that mitochondria dysfunction may play a role in rheumatic pain. The dysfunction is not restricted to neuronal cells in the peripheral and central nervous system, but also includes blood cells and cells at the joint level that may affect pain pathways indirectly. Pre-clinical and clinical data suggest that modulation of mitochondrial functions can be used to attenuate or eliminate pain, which could be beneficial for multiple rheumatic diseases.

Lysophosphatidylcholine 16:0 mediates chronic joint pain associated to rheumatic diseases through acid-sensing ion channel 3

ABSTRACT

Rheumatic diseases are often associated to debilitating chronic pain, which remains difficult to treat and requires new therapeutic strategies. We had previously identified lysophosphatidylcholine (LPC) in the synovial fluids from few patients and shown its effect as a positive modulator of acid-sensing ion channel 3 (ASIC3) able to induce acute cutaneous pain in rodents. However, the possible involvement of LPC in chronic joint pain remained completely unknown. Here, we show, from 2 independent cohorts of patients with painful rheumatic diseases, that the synovial fluid levels of LPC are significantly elevated, especially the LPC16:0 species, compared with postmortem control subjects. Moreover, LPC16:0 levels correlated with pain outcomes in a cohort of osteoarthritis patients. However, LPC16:0 do not appear to be the hallmark of a particular joint disease because similar levels are found in the synovial fluids of a second cohort of patients with various rheumatic diseases. The mechanism of action was next explored by developing a pathology-derived rodent model. Intra-articular injections of LPC16:0 is a triggering factor of chronic joint pain in both male and female mice, ultimately leading to persistent pain and anxiety-like behaviors. All these effects are dependent on ASIC3 channels, which drive sufficient peripheral inputs to generate spinal sensitization processes. This study brings evidences from mouse and human supporting a role for LPC16:0 via ASIC3 channels in chronic pain arising from joints, with potential implications for pain management in osteoarthritis and possibly across other rheumatic diseases.

Defining the relationship between pain intensity and disease activity in patients with rheumatoid arthritis: a secondary analysis of six studies

Background

Pain is the main concern of patients with rheumatoid arthritis (RA) while reducing disease activity dominates specialist management. Disease activity assessments like the disease activity score for 28 joints with the erythrocyte sedimentation rate (DAS28-ESR) omit pain creating an apparent paradox between patients’ concerns and specialists’ treatment goals. We evaluated the relationship of pain intensity and disease activity in RA with three aims: defining associations between pain intensity and disease activity and its components, evaluating discordance between pain intensity and disease activity, and assessing temporal changes in pain intensity and disease activity.

Methods

We undertook secondary analyses of five trials and one observational study of RA patients followed for 12 months. The patients had early and established active disease or sustained low disease activity or remission. Pain was measured using 100-mm visual analogue scales. Individual patient data was pooled across all studies and by types of patients (early active, established active and established remission). Associations of pain intensity and disease activity were evaluated by correlations (Spearman’s), linear regression methods and Bland-Altman plots. Discordance was assessed by Kappa statistics (for patients grouped into high and low pain intensity and disease activity). Temporal changes were assessed 6 monthly in different patient groups.

Results

A total of 1132 patients were studied: 490 had early active RA, 469 had established active RA and 173 were in remission/low disease activity. Our analyses showed, firstly, that pain intensity is associated with disease activity in general, and particularly with patient global assessments, across all patient groups. Patient global assessments were a reasonable proxy for pain intensity. Secondly, there was some discordance between pain intensity and disease activity across all disease activity levels, reflecting similar discrepancies in patient global assessments. Thirdly, there were strong temporal relationships between changes in disease activity and pain intensity. When mean disease activity fell, mean pain intensity scores also fell; when mean disease activity increased, there were comparable increases in pain intensity.

Conclusions

These findings show pain intensity is an integral part of disease activity, though it is not measured directly in DAS28-ESR. Reducing disease activity is crucial for reducing pain intensity in RA.

The Influence of Adverse Childhood Experiences in Pain Management: Mechanisms, Processes, and Trauma-Informed Care

Adverse childhood experiences (ACEs) increase the likelihood of reduced physical and psychological health in adulthood. Though understanding and psychological management of traumatic experiences is growing, the empirical exploration of ACEs and physical clinical outcomes remains under-represented and under-explored. This topical review aimed to highlight the role of ACEs in the experience of chronic pain, pain management services and clinical decision making by: (1) providing an overview of the relationship between ACEs and chronic pain; (2) identifying biopsychosocial mechanisms through which ACEs may increase risk of persistent pain; (3) highlighting the impact of ACEs on patient adherence and completion of pain management treatment; and (4) providing practical clinical implications for pain management. Review findings demonstrated that in chronic pain, ACEs are associated with increased pain complications, pain catastrophizing and depression and the combination of these factors further heightens the risk of early treatment attrition. The pervasive detrimental impacts of the COVID-19 pandemic on ACEs and their cyclical effects on pain are discussed in the context of psychological decline during long treatment waitlists. The review highlights how people with pain can be further supported in pain services by maintaining trauma-informed practices and acknowledging the impact of ACEs on chronic pain and detrimental health outcomes. Clinicians who are ACE-informed have the potential to minimize the negative influence of ACEs on treatment outcomes, ultimately optimizing the impact of pain management services.

Early response to JAK inhibitors on central sensitization and pain catastrophizing in patients with active rheumatoid arthritis

Objectives

To evaluate the effect of 4 weeks of treatment with Janus kinase inhibitors (JAKis) on central sensitization (CS) and pain catastrophizing, and to determine the pain-related variables predictive of disease activity improvement, in patients with active rheumatoid arthritis (RA).

Methods

Consecutive RA patients with active disease starting a JAKi have been enrolled in this prospective observational study. Patients have been assessed at baseline and after 4 weeks of treatment. The evaluation was comprehensive of disease activity [Simplified Disease Activity Index (SDAI) and ultrasonographic (US) score] and of questionnaires aimed at investigating primarily CS [Central Sensitization Inventory (CSI)] and pain catastrophizing [Pain Catastrophizing Scale (PCS)]. Differences (Δ values) between the final and baseline were studied with the t test, Δ values of the variables were correlated with each other using Pearson’s test, and predictor variables for improvement in SDAI were also investigated using multivariate regression analysis.

Results

A total of 115 patients were evaluated. Overall, all variables demonstrated significant improvement between baseline and final except the US score. In particular, CSI decreased from 36.73 to 32.57 (p < 0.0001), PCS decreased from 32.46 to 28.72 (p = 0.0001). ΔSDAI showed a significant correlation with both ΔPCS and ΔCSI (r = 0.466 and 0.386, respectively, p < 0.0001). ΔPCS was the only variable predictive of an improvement in SDAI (coefficient = 0.500, p = 0.0224).

Conclusion

JAKis would appear to have a positive effect on pain-related variables, particularly CS and pain catastrophizing, for the genesis of which extra-synovial mechanisms are responsible.

Autotaxin/Lysophosphatidic Acid Axis: From Bone Biology to Bone Disorders

Lysophosphatidic acid (LPA) is a natural bioactive phospholipid with pleiotropic activities affecting multiple tissues, including bone. LPA exerts its biological functions by binding to G-protein coupled LPA receptors (LPA_1-6) to stimulate cell migration, proliferation, and survival. It is largely produced by autotaxin (ATX), a secreted enzyme with lysophospholipase D activity that converts lysophosphatidylcholine (LPC) into active LPA. Beyond its enzymatic activity, ATX serves as a docking molecule facilitating the efficient delivery of LPA to its specific cell surface receptors. Thus, LPA effects are the result of local production by ATX in a given tissue or cell type. As a consequence, the ATX/LPA axis should be considered as an entity to better understand their roles in physiology and pathophysiology and to propose novel therapeutic strategies. Herein, we provide not only an extensive overview of the relevance of the ATX/LPA axis in bone cell commitment and differentiation, skeletal development, and bone disorders, but also discuss new working hypotheses emerging from the interplay of ATX/LPA with well-established signaling pathways regulating bone mass.

Achieving pain control in early rheumatoid arthritis with baricitinib monotherapy or in combination with methotrexate versus methotrexate monotherapy

Objectives

This post hoc analysis assessed speed, magnitude and maintenance of pain improvement in patients with early rheumatoid arthritis (RA) receiving baricitinib, baricitinib and methotrexate (MTX), or MTX over 1 year. Cumulative pain and quality of life benefits were also assessed.

Methods

Randomised, double-blind, phase 3 study RA-BEGIN (NCT01711359) compared baricitinib 4 mg (N=159), baricitinib 4 mg +MTX (N=215) and MTX (N=210) in patients with RA who had no or limited prior disease-modifying antirheumatic drug treatment. Pain was assessed on a 0–100 mm Visual Analogue Scale (VAS). Proportion of patients with ≥30%, ≥50% and ≥70% pain improvement from baseline; ≤20 mm and ≤10 mm on the pain VAS; and time to achieve pain improvement thresholds were assessed over 52 weeks, as were Patient Global Assessment (PtGA) and 36-Item Short Form Health Survey Physical Component Score (SF-36 PCS) outcomes.

Results

Baricitinib monotherapy or combination with MTX provides greater (least square mean changes (LSM) from baseline −40 mm and −43 mm, respectively) and more rapid (median 12 and 8 weeks to ≥70% improvement, respectively) pain relief than MTX alone (LSM −31 mm, median 20 weeks to ≥70% improvement) over 52 weeks. Baricitinib, alone or combination, provides 9–10 additional weeks of limited to no pain, similar gain in achievable wellness measured through PtGA, and 5–7 additional weeks with change in SF-36 PCS ≥5 vs MTX over 1 year.

Conclusions

Patients treated with baricitinib reported significantly greater and more rapid pain relief, more weeks with limited to no pain, and clinically meaningful improvements in physical health than patients treated with MTX alone over 1 year.

Pain-like behavior in the collagen antibody-induced arthritis model is regulated by lysophosphatidic acid and activation of satellite glia cells

Inflammatory and neuropathic-like components underlie rheumatoid arthritis (RA)-associated pain, and lysophosphatidic acid (LPA) is linked to both joint inflammation in RA patients and to neuropathic pain. Thus, we investigated a role for LPA signalling using the collagen antibody-induced arthritis (CAIA) model. Pain-like behavior during the inflammatory phase and the late, neuropathic-like phase of CAIA was reversed by a neutralizing antibody generated against LPA and by an LPA_1/3 receptor inhibitor, but joint inflammation was not affected. Autotaxin, an LPA synthesizing enzyme was upregulated in dorsal root ganglia (DRG) neurons during both CAIA phases, but not in joints or spinal cord. Late-phase pronociceptive neurochemical changes in the DRG were blocked in Lpar1 receptor deficient mice and reversed by LPA neutralization. In vitro and in vivo studies indicated that LPA regulates pain-like behavior via the LPA₁ receptor on satellite glia cells (SGCs), which is expressed by both human and mouse SGCs in the DRG. Furthermore, CAIA-induced SGC activity is reversed by phospholipid neutralization and blocked in Lpar1 deficient mice. Our findings suggest that the regulation of CAIA-induced pain-like behavior by LPA signalling is a peripheral event, associated with the DRGs and involving increased pronociceptive activity of SGCs, which in turn act on sensory neurons.

Immune regulation of pain: Friend and foe

[Figure: see text].

Patients' Characterization of Medication, Emotions, and Incongruent Perceptions around Adherence

Medication nonadherence is prevalent among patients with chronic diseases. Previous research focused on patients’ beliefs in medication or illness and applied risk-benefit analyses when reasoning their behavior. This qualitative study examined rheumatoid arthritis (RA) patients’ perceptions and feelings toward medication in parallel with attitudes about their own adherence. We conducted four 90-min focus groups and seven 60-min interviews with a diverse sample of RA patients (n = 27). Discussions covered dilemmas encountered, emotions, and thought process concerning medication, and included application of projective techniques. Transcripts were analyzed in NVivo-12 using a thematic coding framework through multiple rounds of deduction and categorization. Three themes emerged, each with mixed sentiments. (1) Ambivalent feelings toward medication: participants experienced internal conflicts as their appreciation of drugs for relief contradicted worries about side effects or “toxicity” and desire to not identify as sick, portraying medications as “best friend” and “evil”. (2) Struggles in taking medication: participants “hated” the burden of managing regimen and resented the reliance and embarrassment. (3) Attitudes and behavior around adherence: most participants self-reported high adherence yet also described frequently self-adjusting medications, displaying perception-action incongruency. Some expressed nervousness and resistance while others felt empowered when modifying dosage, which might have motivated or helped them self-justify nonadherence. Only a few who deviated from prescription discussed it with their clinicians though most participants expressed the desire to do so; open communication with providers reinforced a sense of confidence and control of their own health. Promoting personalized care with shared decision-making that empowers and supports patients in managing their long-term treatment could encourage adherence and improve overall health outcome.

TrkA specific signalling pathways are critical for mechanical allodynia development and bone alterations in a mouse model of rheumatoid arthritis

ABSTRACT

Rheumatoid arthritis is frequently associated with chronic pain that still remains difficult to treat. Targeting nerve growth factor (NGF) seems very effective to reduce pain in at least, osteoarthritis and chronic low back pain but leads to some potential adverse events. Our aim was to better understand the involvement of the intracellular signalling pathways activated by NGF through its specific tyrosine kinase type A (TrkA) receptor in the pathophysiology of rheumatoid arthritis using the complete Freund adjuvant model in our knock-in TrkA/C mice. Our multimodal study demonstrated that knock-in TrkA/C mice exhibited a specific decrease of mechanical allodynia, weight bearing deficit, peptidergic (CGRP+) and sympathetic (TH+) peripheral nerve sprouting in the joints, a reduction in osteoclast activity and bone resorption markers, and a decrease of CD68 positive cells in the joint with no apparent changes in joint inflammation compared to WT mice following arthritis. Finally, transcriptomic analysis show several differences in DRGs mRNA expression of putative mechanotransducers such as ASIC3 and TRAAK as well as intracellular pathways such as c-Jun in the joint/DRGs. These results suggest that TrkA specific intracellular signalling pathways are specifically involved in mechanical hypersensitivity and bone alterations following arthritis using TrkA/C mice.

Pain in rheumatoid arthritis: a seven-year follow-up study of pain distribution and factors associated with transition from and to chronic widespread pain

Objective: To study transitions from and to chronic widespread pain (CWP) over 7 years in patients with rheumatoid arthritis (RA).Method: Two postal questionnaires were sent to patients included in the BARFOT (Better Anti-Rheumatic Pharmacotherapy) study, the first in 2010 and the second in 2017. The questionnaires assessed pain, number of tender and swollen joints, functional disability, health-related quality of life (HRQoL), pharmacological treatment, lifestyle factors, and patient-reported body mass index (BMI). The responders to both questionnaires were divided into three groups according to the reported pain duration and distribution: patients having no chronic pain (NCP), chronic regional pain (CRP), and CWP.Results: In all, 953 patients answered the questionnaires at both time-points. One-third (324) of the patients reported CWP in 2010, and 140 (43%) of the patients had transition to NCP or CRP in 2017. In multivariate logistic regression models, adjusting for age, gender, and disease duration, transition from CWP was associated with normal BMI, fewer tender joints, less pain, less fatigue, fewer pain regions, less disability, better HRQoL, and biologic treatment. In 2010, 628 patients reported NCP or CRP, whereas 114 of them reported CWP in 2017. Transition to CWP was associated with female gender, obesity, more tender and swollen joints, higher pain-related variables, worse disability, and worse HRQoL.Conclusion: There are modifiable factors associated with transitions from and to CWP that could be identified. Paying attention to these factors could improve pain treatment in the management of RA.

Pain Over Two Years After Start of Biologic Versus Conventional Combination Treatment in Early Rheumatoid Arthritis: Results From a Swedish Randomized Controlled Trial

OBJECTIVE

To compare the pain course between methotrexate (MTX)-refractory early rheumatoid arthritis (RA) patients randomized to infliximab (IFX) versus sulfasalazine (SSZ) plus hydroxychloroquine (HCQ).

METHODS

The randomized, controlled, open-label Swedish Pharmacotherapy (SWEFOT) trial enrolled new-onset RA patients from October 2002 to December 2005. After 3 months of receiving MTX, patients not reaching low disease activity (Disease Activity Score in 28 joints score ≤3.2) were randomized to adding IFX (n = 128) or SSZ plus HCQ (n = 130) and followed for 21 months. Here, outcomes included area under the curve (AUC) for visual analog scale (VAS) scores for pain, unacceptable pain (VAS pain score >40 mm [range 0-100]), and unacceptable pain despite inflammation control (refractory pain; VAS pain score >40 plus C-reactive protein level <10 mg/liter). Between-group differences were analyzed with multivariate regression models.

RESULTS

Overall, 50% of randomized patients (n = 258) in the crude setting reported unacceptable pain at randomization, declining to 29% at 21 months (P < 0.001), when refractory pain constituted 82% of all unacceptable pain. Comparing randomized arms (intent-to-treat analysis), the AUC for VAS pain was lower in the MTX plus IFX group (P = 0.01), and at 21 months, 32% of patients receiving MTX plus IFX and 45% receiving MTX plus SSZ plus HCQ had unacceptable pain (adjusted relative risk 0.68 [95% confidence interval 0.51, 0.90]; P = 0.008). Regarding refractory pain, no between-group differences were observed.

CONCLUSION

Despite active combination treatment, almost one-third of new-onset RA patients reported unacceptable pain after 21 months, and refractory pain constituted more than 4/5 of this pain load. Adding IFX versus SSZ plus HCQ to MTX reduced both cumulative pain and unacceptable pain at 21 months, suggesting less long-term pain for the biologic therapy. These results display insufficient effects of current treatment strategies on inflammation-independent pain components, warranting alternative approaches in affected patients.

Qualitative and psychometric approaches to evaluate the PROMIS pain interference and sleep disturbance item banks for use in patients with rheumatoid arthritis

Background

Patients with rheumatoid arthritis (RA) commonly experience pain despite the availability of disease-modifying treatments. Sleep disturbances are frequently reported in RA, with pain often a contributing factor. The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference and Sleep Disturbance item banks were initially developed to provide insights into the patient experience of pain and sleep, respectively, though they were not specifically intended for use in RA populations. This study evaluated the content validity of the PROMIS Pain Interference and Sleep Disturbance item banks in RA and identified relevant content for short forms for patients with RA that achieved high measurement precision across a broad range of health.

Methods

A qualitative approach consisting of hybrid concept elicitation and cognitive debriefing interviews was used to evaluate the content validity of the item banks in RA. Interviews were semi-structured and open-ended, allowing a range of concepts and responses to be captured. Findings from the qualitative interviews were used to select the most relevant items for the short forms, and psychometric evaluation, using existing item-response theory (IRT) item parameters, was used to evaluate the marginal reliability and measurement precision of the short forms across the range of the latent variables (i.e. pain interference and sleep disturbance).

Results

Thirty-two participants were interviewed. Participants reported that RA-related pain and sleep disturbances have substantial impacts on their daily lives, particularly with physical functioning. The PROMIS Pain Interference and Sleep Disturbance item banks were easy to understand and mostly relevant to their RA experiences, and the 7-day recall period was deemed appropriate. Qualitative and IRT-based approaches identified short forms for Pain Interference (11 items) and Sleep Disturbance (7 items) that had high relevance and measurement precision, with good coverage of the concepts identified by participants during concept elicitation.

Conclusion

Pain and sleep disturbances affect many aspects of daily life in patients with RA and should be considered when novel treatments are developed. This study supports the use of the PROMIS Pain Interference and Sleep Disturbance item banks in RA, and the short forms developed herein have the potential to be used in clinical studies of RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-021-00318-w.

The efficacy of systemic glucocorticosteroids for pain in rheumatoid arthritis: a systematic literature review and meta-analysis

Objectives

Glucocorticosteroids (GCs) are recommended to suppress inflammation in people with active RA. This systematic review and meta-analysis aimed to quantify the effects of systemic GCs on RA pain.

Methods

A systematic literature review of randomized controlled trials (RCTs) in RA comparing systemic GCs to inactive treatment. Three databases were and spontaneous pain and evoked pain outcomes were extracted. Standardized mean differences (SMDs) and mean differences were meta-analysed. Heterogeneity (I², tau statistics) and bias (funnel plot, Egger’s test) were assessed. Subgroup analyses investigated sources of variation. This study was pre-registered (PROSPERO CRD42019111562).

Results

A total of 18 903 titles, 880 abstracts and 226 full texts were assessed. Thirty-three RCTs suitable for the meta-analysis included 3123 participants. Pain scores (spontaneous pain) decreased in participants treated with oral GCs; SMD = −0.65 (15 studies, 95% CI −0.82, −0.49, P <0.001) with significant heterogeneity (I² = 56%, P =0.0002). Efficacy displayed time-related decreases after GC initiation. Mean difference visual analogue scale pain was −15 mm (95% CI −20, −9) greater improvement in GC than control at ≤3 months, −8 mm (95% CI −12, −3) at >3–6 months and −7 mm (95% CI −13, 0) at >6 months. Similar findings were obtained when evoked pain outcomes were examined. Data from five RCTs suggested improvement also in fatigue during GC treatment.

Conclusion

Oral GCs are analgesic in RA. The benefit is greatest shortly after initiation and GCs might not achieve clinically important pain relief beyond 3 months. Treatments other than anti-inflammatory GCs should be considered to reduce the long-term burden of pain in RA.

Central Aspects of Pain in Rheumatoid Arthritis (CAP-RA): protocol for a prospective observational study

BACKGROUND

Pain and fatigue are persistent problems in people with rheumatoid arthritis. Central sensitisation (CS) may contribute to pain and fatigue, even when treatment has controlled inflammatory disease. This study aims to validate a self-report 8-item questionnaire, the Central Aspects of Pain in Rheumatoid Arthritis (CAP-RA) questionnaire, developed to measure central pain mechanisms in RA, and to predict patient outcomes and response to treatment. A secondary objective is to explore mechanisms linking CS, pain and fatigue in people with RA.

METHODS/DESIGN

This is a prospective observational cohort study recruiting 250 adults with active RA in secondary care. The CAP-RA questionnaire, demographic data, medical history, and patient reported outcome measures (PROMs) of traits associated with central sensitization will be collected using validated questionnaires. Quantitative sensory testing modalities of pressure pain detection thresholds, temporal summation and conditioned pain modulation will be indices of central sensitization, and blood markers, swollen joints and ultrasound scans will be indices of inflammation. Primary data collection will be at baseline and 12 weeks. The test-retest reliability of CAP-RA questionnaire will be determined 1 week after the baseline visit. Pain and fatigue data will be collected weekly via text messages for 12 weeks. CAP-RA psychometric properties, and predictive validity for outcomes at 3 months will be evaluated.

DISCUSSION

This study will validate a simple self-report questionnaire against psychophysical indices of central sensitization and patient reported outcome measures of traits associated with CS in a population of individuals with active RA. The application of this instrument in the clinical environment could provide a mechanism-based stratification tool to facilitate the provision of targeted therapy to individuals with pain and fatigue in RA, alongside treatments that target joint inflammation.

TRIAL REGISTRATION

Clinicaltrials.gov NCT04515589 . Date of registration 17 August 2020.

Autoimmune regulation of chronic pain

Chronic pain is an unpleasant and debilitating condition that is often poorly managed by existing therapeutics. Reciprocal interactions between the nervous system and the immune system have been recognized as playing an essential role in the initiation and maintenance of pain. In this review, we discuss how neuroimmune signaling can contribute to peripheral and central sensitization and promote chronic pain through various autoimmune mechanisms. These pathogenic autoimmune mechanisms involve the production and release of autoreactive antibodies from B cells. Autoantibodies-ie, antibodies that recognize self-antigens-have been identified as potential molecules that can modulate the function of nociceptive neurons and thereby induce persistent pain. Autoantibodies can influence neuronal excitability by activating the complement pathway; by directly signaling at sensory neurons expressing Fc gamma receptors, the receptors for the Fc fragment of immunoglobulin G immune complexes; or by binding and disrupting ion channels expressed by nociceptors. Using examples primarily from rheumatoid arthritis, complex regional pain syndrome, and channelopathies from potassium channel complex autoimmunity, we suggest that autoantibody signaling at the central nervous system has therapeutic implications for designing novel disease-modifying treatments for chronic pain.

Pain: A Review of Interleukin-6 and Its Roles in the Pain of Rheumatoid Arthritis

Pain is a major and common symptom reported as a top priority in patients with rheumatoid arthritis (RA). Intuitively, RA-related pain is often considered to be a natural consequence of peripheral inflammation, so treatment of RA is expected to manage pain concurrently as part of inflammation control. However, pain in patients with RA can be poorly correlated with objective measures of inflammation, for example, in patients who are otherwise in remission. Joint damage appears to account for only a fraction of this residual pain. Emerging evidence suggests that alteration of peripheral and central pain processing contributes to RA-related pain; this is parallel to, but somewhat independent of, joint inflammation. Interleukin (IL)-6 is a proinflammatory cytokine that contributes to the pathogenesis of RA. It exerts systemic effects via signaling through soluble forms of the IL-6 receptor (“trans-signaling”). Evidence from preclinical studies demonstrates that intra-articular IL-6 can produce long-lasting peripheral sensitization to mechanical stimulation and suggests an important role for IL-6 in central pain sensitization. This may be partly explained by its ability to activate neurons through trans-signaling, affecting nociceptive plasticity and nerve fiber regrowth. Local activity at neuron endings may culminate in altered pain processing in the central nervous system because of persistent signaling from sensitized peripheral neurons. Peripheral and central sensitization can promote the development of chronic pain, which can have a significant impact on patients’ health and quality of life. A proportion of pain in RA may be more appropriately managed as an entity separate from inflammation. Both the peripheral and central nervous systems should be recognized as important potential systems targeted by RA. The substantial burden of RA-related chronic pain suggests that pain should be a key focus in RA management and should be assessed and addressed early and separately from the inflammatory component.

Sexual Dimorphism in the Expression of Pain Phenotype in Preclinical Models of Rheumatoid Arthritis

Rheumatoid arthritis is one of most frequent rheumatic diseases, affecting around 1% of the population worldwide. Pain impacting the quality of life for the patient with rheumatoid arthritis, is often the primary factor leading them to seek medical care. Although sex-related differences in humans and animal models of rheumatoid arthritis are described, the correlation between pain and sex in rheumatoid arthritis has only recently been directly examined. Here we review the literature and explore the mechanisms underlying the expression of the pain phenotype in females and males in preclinical models of rheumatoid arthritis.

The burden of waiting to access pain clinic services: perceptions and experiences of patients with rheumatic conditions

BACKGROUND

Extensive waiting times before receiving services is a major barrier to adequate pain management. Waiting times may have a detrimental impact on patients' conditions and quality of life. However, there remains a lack of knowledge on the actual experiences of patients waiting to receive services, especially for those with rheumatic conditions. The present study aimed to gain an in-depth understanding of perceptions and experiences of patients with rheumatic conditions regarding access to pain clinic services. The secondary objective was to identify possible solutions to improve this access according to patients' perspectives.

METHODS

This qualitative study based on semi-structured interviews was conducted with adults with rheumatic conditions waiting to access pain clinics in the province of Quebec, Canada. Interviews were transcribed verbatim and analyzed using thematic content analysis.

RESULTS

Twenty-six participants were interviewed (22 women and 4 men; mean age 54 ± 10 years). Four main themes were identified: 1) the perception that waiting time is unacceptably long; 2) how the lack of information affects patients' experiences of waiting; 3) patients' various expectations towards the pain clinic, from high hopes to disillusionment and 4) carrying an emotional, physical and financial burden resulting from the wait. Participants reported several solutions to improve the experience of waiting, including providing information to patients, increasing resources, improving prioritization processes and care coordination, and providing alternative interventions to patients during the wait.

CONCLUSIONS

For patients with rheumatic conditions, access to pain clinic services is challenging due to extensive waiting times. The burden it imposes on them adds to the existing challenge of living with a chronic rheumatic condition. The solutions identified by participants could serve as building blocks to develop and implement measures to improve patients' experience of accessing pain-related services.

The Jak/STAT pathway: A focus on pain in rheumatoid arthritis

Pain is a manifestation of rheumatoid arthritis (RA) that is mediated by inflammatory and non-inflammatory mechanisms and negatively affects quality of life. Recent findings from a Phase 3 clinical trial showed that patients with RA who were treated with a Janus kinase 1 (Jak1) and Janus kinase 2 (Jak2) inhibitor achieved significantly greater improvements in pain than those treated with a tumor necrosis factor blocker; both treatments resulted in similar changes in standard clinical measures and markers of inflammation. These findings suggest that Jak1 and Jak2 inhibition may relieve pain in RA caused by inflammatory and non-inflammatory mechanisms and are consistent with the overarching involvement of the Jak-signal transducer and activator of transcription (Jak/STAT) pathway in mediating the action, expression, and regulation of a multitude of pro- and anti-inflammatory cytokines. In this review, we provide an overview of pain in RA, the underlying importance of cytokines regulated directly or indirectly by the Jak/STAT pathway, and therapeutic targeting of the Jak/STAT pathway in RA. As highlighted herein, multiple cytokines directly or indirectly regulated by the Jak/STAT pathway play important roles in mediating various mechanisms underlying pain in RA. Having a better understanding of these mechanisms may help clinicians make treatment decisions that optimize the control of inflammation and pain.

Neuropathic pain in a sample of Egyptian patients with rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is an autoimmune disease characterized by polyarthritis that may cause irreversible joint disability. Pain is the most important symptom in RA patients that requires more attention and careful evaluation. Despite the improvement in medications used to control inflammation in RA patients, a relevant number of them still experience neuropathic pain even with disease remission. This study was conducted to estimate the frequency of neuropathic pain (NP) in RA patients and to assess its relationship with disease activity, functional status, and overweight.

Results

NP was detected in 12.5% (14 patients) of RA patients. Highly significant differences were found between RA patients with NP and those without NP as regards disease duration, visual analog scale (VAS) of pain, disease activity score 28 (DAS28-ESR), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), body mass index (BMI), health assessment questionnaire (HAQ) score, and Douleur Neuropathique in 4 (DN4) questionnaire for NP assessment (p < 0.001). The correlation between the DN4 questionnaire and the parameters of disease activity in RA patients with NP was not significant. By univariate analysis, the possible risk factors for NP in RA patients were disease duration, VAS, DAS28-ESR, HAQ, and BMI; however, by multivariate analysis, no possible risk factors for NP in RA patients were detected.

Conclusion

Although pain in patients with RA was classified as nociceptive in nature, a relevant proportion of patients might also have NP. NP in RA patients was related to functional disability, high disease activity, and overweight.

The Neuroimmunology of Chronic Pain: From Rodents to Humans

Chronic pain, encompassing conditions, such as low back pain, arthritis, persistent post-surgical pain, fibromyalgia, and neuropathic pain disorders, is highly prevalent but remains poorly treated. The vast majority of therapeutics are directed solely at neurons, despite the fact that signaling between immune cells, glia, and neurons is now recognized as indispensable for the initiation and maintenance of chronic pain. This review highlights recent advances in understanding fundamental neuroimmune signaling mechanisms and novel therapeutic targets in rodent models of chronic pain. We further discuss new technological developments to study, diagnose, and quantify neuroimmune contributions to chronic pain in patient populations.

The neuropathic phenotype of the K/BxN transgenic mouse with spontaneous arthritis: pain, nerve sprouting and joint remodeling

The adult K/BxN transgenic mouse develops spontaneous autoimmune arthritis with joint remodeling and profound bone loss. We report that both males and females display a severe sustained tactile allodynia which is reduced by gabapentin but not the potent cyclooxygenase inhibitor ketorolac. In dorsal horn, males and females show increased GFAP⁺ astrocytic cells; however, only males demonstrate an increase in Iba1⁺ microglia. In dorsal root ganglia (DRG), there is an increase in CGRP⁺, TH⁺, and Iba1⁺ (macrophage) labeling, but no increase in ATF3⁺ cells. At the ankle there is increased CGRP⁺, TH⁺, and GAP-43⁺ fiber synovial innervation. Thus, based on the changes in dorsal horn, DRG and peripheral innervation, we suggest that the adult K/BxN transgenic arthritic mice display a neuropathic phenotype, an assertion consistent with the analgesic pharmacology seen in this animal. These results indicate the relevance of this model to our understanding of the nociceptive processing which underlies the chronic pain state that evolves secondary to persistent joint inflammation.

The burden of pain in rheumatoid arthritis: Impact of disease activity and psychological factors

BACKGROUND

Pain remains a prevalent symptom for rheumatoid arthritis (RA) patients despite a wide therapeutic choice. The objective of this study was to provide a multidimensional evaluation of pain.

METHODS

A total of 295 RA patients from 7 French rheumatology centres were enrolled in a cross-sectional study. Patients completed a chronic pain assessment questionnaire approved by the French National Authority for Health, the health assessment questionnaire (HAQ) as well as depression and anxiety scales (HAD, Beck Depression Inventory, STAI). Disease activity (DAS28) and ESR were recorded. A multivariate descriptive analysis was undertaken using principal component analysis (PCA).

RESULTS

38.4% of patients had a pain score > 40 mm/100, although 83% were on biological treatment and 38.7% were in remission based on the RA activity score. The PCA analysis found four axes representing 70% of total variance. The axes, per cent of variance and variables represented were as follows: (a) axis 1, 41% variance, anxiety and depression scores, sensory and affective qualifier score, HAQ and pain impact on daily life; (b) axis 2, 13% variance, disease activity score (DAS28) and pain relief with current treatment; (c) axis 3, 9% of variance, RA duration and radiographic score and (d) axis 4, 6% of variance, DAS28 and ESR. Moderate to severe pain was significantly associated with axes 1 and 2.

CONCLUSIONS

Despite a high proportion of patients on biological treatments, 38.4% of patients continue to experience moderate to severe pain. Pain is associated with the RA activity score, but also with the depression and anxiety scores.

SIGNIFICANCE

Substantial proportion of rheumatoid arthritis (RA) patients still experiences relevant pain, although more than 80% on biological treatment. Pain is primarily associated with anxiety and depression scores and with disease activity score. These findings highlight the need to assess patients' mental well-being alongside. Clinical measures of disease activity to better manage pain and guide treatment decisions.

Understanding the Role of Interleukin-6 (IL-6) in the Joint and Beyond: A Comprehensive Review of IL-6 Inhibition for the Management of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, debilitating autoimmune disorder involving inflammation and progressive destruction of the joints, affecting up to 1% of the population. The majority of patients with RA have one or more comorbid conditions, the most common being cardiovascular disease, osteoporosis, and depression, the presence of which are associated with poorer clinical outcomes and lower health-related quality of life. RA pathogenesis is driven by a complex network of proinflammatory cells and cytokines, and of these, interleukin-6 (IL-6) plays a key role in the chronic inflammation associated with RA. Through cell signaling that can be initiated by both membrane-bound and soluble forms of its receptor, IL-6 acts both locally to promote joint inflammation and destruction, and in the circulation to mediate extra-articular manifestations of RA, including pain, fatigue, morning stiffness, anemia, and weight loss. This narrative review describes the role of IL-6 in the pathogenesis of RA, its comorbidities, and extra-articular systemic manifestations, and examines the effects of the IL-6 receptor inhibitors sarilumab and tocilizumab on clinical endpoints of RA, patient-reported outcomes, and common comorbidities and extra-articular manifestations.

BARICITINIB: NEW PHARMACOTHERAPY OPTIONS FOR RHEUMATOID ARTHRITIS AND OTHER IMMUNE-MEDIATED INFLAMMATORY RHEUMATIC DISEASES

Deciphering the mechanisms of the pathogenesis of immune-mediated inflammatory rheumatic diseases (IMIRDs) in conjunction with designing a wide range of biological agents is one of the major medical advances in the 21st century. A new promising area of pharmacotherapy for IMIRDs is associated with the design of the so-called targeted oral medications that primarily include Janus kinase (JAK) inhibitors. The review presents new data on the efficacy and safety of the new JAK inhibitor baricitinib in treating rheumatoid arthritis and other IMIRDs.

Effect of phenolic compounds from Oenothera rosea on the kaolin-carrageenan induced arthritis model in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Oenothera rosea (Onagraceae), commonly known as "hierba del golpe" in Mexico, is an herbaceous plant widely used in Mexican traditional medicine for the treatment of pain and inflammation.

AIM OF THE STUDY

The aim of this study was to assess the effect of extracts and compounds isolated from O. rosea in kaolin-carrageenan induced arthritis.

MATERIALS AND METHODS

Hydroalcoholic extract from aerial parts of O. rosea was obtained and chemically separated in order to obtain OrEA and isolated compounds using column chromatography, HPLC, UPLC and NMR analysis. O. rosea extract and derivatives were tested on the kaolin/carrageenan (K/C) induced arthritis model on ICR mice. Knee inflammation and paw withdrawal threshold were assessed following intraarticular administration of kaolin and carrageenan (4% and 2%, respectively) and subsequent oral administration of O. rosea. TNF-α, IL-1β, IL-6 and IL-10 levels from synovial capsule were measured using ELISA kits. NF-κB activity was also measured using the RAWBlue™ cell line. Finally, spleen and lungs were dissected to investigate body index.

RESULTS

Oral administration of the O. rosea ethyl acetate fraction (25, 50 and 100 mg/kg) and isolated compounds (2 mg/kg) reduced the edema induced by kaolin/carrageenan, similar to the effect of methotrexate (1 mg/kg). Hyperalgesia but not allodynia was observed during this experiment. O. rosea derivatives reduced this behavior. The quantification of cytokines showed a reduction in TNF-α, IL-1β and IL-6, as well as an increase of IL-10. NF-κB production was also reduced by administering O. rosea derivatives. Chemical analysis of O. rosea derivatives showed that the major compounds present in the ethyl acetate fraction were phenolic compounds. Gallic acid, quercetin glucoside and quercetin rhamnoside were separated and identified by UPLC-UV-MS, and myricetin glycoside and tamarixetin glucoside using ¹H and ¹³C NMR.

CONCLUSIONS

O. rosea produces different phenolic compounds capable of reducing the inflammation and secondary mechanical hyperalgesia produced by K/C administration. They also reduced proinflammatory cytokines and increased anti-inflammatory cytokines. Finally, NF-κB modulation was reduced by the administration of O. rosea. Therefore, O. rosea could be considered of interest in inflammatory and painful diseases.

Lipid rafts in glial cells: role in neuroinflammation and pain processing

Activation of microglia and astrocytes secondary to inflammatory processes contributes to the development and perpetuation of pain with a neuropathic phenotype. This pain state presents as a chronic debilitating condition and affects a large population of patients with conditions like rheumatoid arthritis and diabetes, or after surgery, trauma, or chemotherapy. Here, we review the regulation of lipid rafts in glial cells and the role they play as a key component of neuroinflammatory sensitization of central pain signaling pathways. In this context, we introduce the concept of an inflammaraft (i-raft), enlarged lipid rafts harboring activated receptors and adaptor molecules and serving as an organizing platform to initiate inflammatory signaling and the cellular response. Characteristics of the inflammaraft include increased relative abundance of lipid rafts in inflammatory cells, increased content of cholesterol per raft, and increased levels of inflammatory receptors, such as toll-like receptor (TLR)4, adaptor molecules, ion channels, and enzymes in lipid rafts. This inflammaraft motif serves an important role in the membrane assembly of protein complexes, for example, TLR4 dimerization. Operating within this framework, we demonstrate the involvement of inflammatory receptors, redox molecules, and ion channels in the inflammaraft formation and the regulation of cholesterol and sphingolipid metabolism in the inflammaraft maintenance and disruption. Strategies for targeting inflammarafts, without affecting the integrity of lipid rafts in noninflammatory cells, may lead to developing novel therapies for neuropathic pain states and other neuroinflammatory conditions.

Contribution of Inflammation and Bone Destruction to Pain in Arthritis: A Study in Murine Glucose-6-Phosphate Isomerase-Induced Arthritis

OBJECTIVE

Arthritis is often characterized by inflammation and bone destruction. This study was undertaken to investigate the contribution of inflammation and bone destruction to pain.

METHODS

Inflammation, bone resorption, pain-related behaviors, and molecular markers (activating transcription factor 3 [ATF-3], p-CREB, and transient receptor potential vanilloid channel 1) in sensory neurons were measured in murine glucose-6-phosphate isomerase (G6PI)-induced arthritis, a model of rheumatoid arthritis. Depletion of Treg cells before immunization changed self-limiting arthritis into nonremitting arthritis with pronounced bone destruction. Zoledronic acid (ZA) was administered to reduce bone resorption.

RESULTS

Compared to nondepleted mice, Treg cell-depleted mice exhibited arthritis with more severe bone destruction and higher guarding scores (P < 0.05; n = 10 mice per group) as well as more persistent thermal hyperalgesia (P < 0.05), but displayed similar mechanical hyperalgesia at the hindpaws (n = 18-26 mice per group). These pain-related behaviors, as well as an up-regulation of the neuronal injury marker ATF-3 in sensory neurons (studied in 39 mice), appeared before the clinical score (inflammation) became positive and persisted in Treg cell-depleted and nondepleted mice. In the late stage of arthritis, Treg cell-depleted mice treated with ZA showed less bone resorption (<50%; P < 0.01) and less thermal hyperalgesia (P < 0.01) than Treg cell-depleted mice without ZA treatment (n = 15 mice per group), but ZA treatment did not reduce the clinical score and local mechanical hyperalgesia.

CONCLUSION

Pain-related behaviors precede and outlast self-limiting arthritis. In nonremitting arthritis with enhanced bone destruction, mainly local thermal, but not local mechanical, hyperalgesia was aggravated. The up-regulation of ATF-3 indicates an early and persisting affection of sensory neurons by G6PI-induced arthritis.

Effect of Baricitinib and Adalimumab in Reducing Pain and Improving Function in Patients with Rheumatoid Arthritis in Low Disease Activity: Exploratory Analyses from RA-BEAM

Patients with rheumatoid arthritis (RA) may experience residual pain and functional impairment despite good control of disease activity. This study compared improvements in pain and physical function in patients with well-controlled RA after 24 weeks' treatment with baricitinib, adalimumab or placebo in the 52-week RA-BEAM phase III study. Adults with active RA and inadequate response to methotrexate received baricitinib 4 mg once daily, adalimumab 40 mg every two weeks or placebo, with background methotrexate. Patients (N = 1010) were categorised as in remission, in remission or low disease activity, or not in remission or low disease activity at week 24. For patients in remission or low disease activity (n = 310), improvements in mean pain and physical function scores at week 24 were significantly greater with baricitinib than placebo (p < 0.001 and p < 0.01, respectively) and adalimumab (p < 0.05 for both). For both outcomes, differences between adalimumab and placebo were not significant. The proportions of patients in remission or low disease activity with minimal or no pain and with normalised physical function were numerically greater with baricitinib than placebo. Baricitinib 4 mg once daily provided enhanced improvement in pain and physical function in patients with well-controlled RA, suggesting it may produce effects beyond immunomodulation.

Cartilage-binding antibodies induce pain through immune complex-mediated activation of neurons

Rheumatoid arthritis-associated joint pain is frequently observed independent of disease activity, suggesting unidentified pain mechanisms. We demonstrate that antibodies binding to cartilage, specific for collagen type II (CII) or cartilage oligomeric matrix protein (COMP), elicit mechanical hypersensitivity in mice, uncoupled from visual, histological and molecular indications of inflammation. Cartilage antibody-induced pain-like behavior does not depend on complement activation or joint inflammation, but instead on tissue antigen recognition and local immune complex (IC) formation. smFISH and IHC suggest that neuronal Fcgr1 and Fcgr2b mRNA are transported to peripheral ends of primary afferents. CII-ICs directly activate cultured WT but not FcRγ chain-deficient DRG neurons. In line with this observation, CII-IC does not induce mechanical hypersensitivity in FcRγ chain-deficient mice. Furthermore, injection of CII antibodies does not generate pain-like behavior in FcRγ chain-deficient mice or mice lacking activating FcγRs in neurons. In summary, this study defines functional coupling between autoantibodies and pain transmission that may facilitate the development of new disease-relevant pain therapeutics.

Neuropathic-like pain in psoriatic arthritis: evidence of abnormal pain processing

OBJECTIVES

The primary objective was to investigate the prevalence of neuropathic-like pain in patients with psoriatic arthritis (PsA). Secondary outcomes were to investigate whether mood, fatigue, pain, disease severity and fibromyalgia are associated with neuropathic-like pain in PsA patients.

METHODS

PsA patients were assessed for fatigue, mood, pain, disease activity and fibromyalgia using questionnaires. Neuropathic-like pain was assessed by PainDetect.

RESULTS

Sixty-four patients with PsA were recruited from the Rheumatology Outpatient Department. Of the 64 patients recruited, 26.6% had 'likely neuropathic pain' and 21.9% had 'possible neuropathic-like pain' according to the PainDetect questionnaire. Patients with 'likely neuropathic pain' had higher disease activity, health assessment questionnaire, patient global self-assessment score, tender and swollen joint counts, dactylitis, enthesitis, pain severity and interference with day-to-day activities, fatigue severity and impact, fibromyalgia, anxiety and depression than 'unlikely neuropathic pain' patients (p < 0.05). PainDetect score correlated with measures of disease activity, fatigue, depression, anxiety, Widespread Pain Index and Symptom Severity Scale (all p < 0.05). Most patients (71%) with neuropathic-like pain fulfilled American College of Rheumatology 2010 fibromyalgia criteria. Patients with 'possible neuropathic-like pain' had scores between patients with 'likely neuropathic pain' and 'unlikely neuropathic pain'.

CONCLUSION

Neuropathic-like pain as evidence of abnormal pain processing is common in patients with PsA. It is associated with higher disease activity and fibromyalgia. A significant proportion of patients had 'possible neuropathic-like' pain with intermediate disease and symptom score suggesting neuropathic-like pain as evidence of abnormal pain processing is a continuum rather than concurrent fibromyalgia. Key Points • Neuropathic pain is prevalent in psoriatic arthritis. • Higher levels of pain, disease activity, fatigue, depression, anxiety and comorbidities in Psoriatic arthritis. • Increased pain severity is associated with increased disease activity, fatigue, depression and anxiety.

Accelerated Atherosclerosis in Rheumatoid Arthritis: Mechanisms and Treatment

Background:

Rheumatoid arthritis (RA) is a chronic systemic autoimmune inflammatory disorder that increases the risk of developing cardiovascular disease. There is accumulating evidence that the RA disease state accelerates the formation of atherosclerotic plaques. Treatments for RA improve joint symptomatology and may reduce inflammation, but consideration of their effects on the cardiovascular system is generally low priority.

Objective:

Since cardiovascular disease is the leading cause of mortality in RA patients, the impact of RA therapies on atherosclerosis is an area in need of attention and the focus of this review.

Results:

The drugs used to treat RA may be analgesics, conventional disease-modifying anti-rheumatic drugs, and/or biologics, including antibodies against the cytokine tumor necrosis factor-α. Pain relievers such as nonselective non-steroidal anti-inflammatory drugs and cyclooxygenase inhibitors may adversely affect lipid metabolism and cyclooxygenase inhibitors have been associated with increased adverse cardiovascular events, such as myocardial infarction and stroke. Methotrexate, the anchor disease-modifying anti-rheumatic drug in RA treatment has multiple atheroprotective advantages and is often combined with other therapies. Biologic inhibitors of tumor necrosis factor-α may be beneficial in preventing cardiovascular disease because tumor necrosis factor-α promotes the initiation and progression of atherosclerosis. However, some studies show a worsening of the lipid profile in RA with blockade of this cytokine, leading to higher total cholesterol and triglycerides.

Conclusion:

Greater understanding of the pharmacologic activity of RA treatments on the atherosclerotic process may lead to improved care, addressing both damages to the joints and heart.