Pain in rheumatoid arthritis: a critical review

microRNAs: critical targets for treating rheumatoid arthritis angiogenesis

Vascular neogenesis, an early event in the development of rheumatoid arthritis (RA) inflammation, is critical for the formation of synovial vascular networks and plays a key role in the progression and persistence of chronic RA inflammation. microRNAs (miRNAs), a class of single-stranded, non-coding RNAs with approximately 21-23 nucleotides in length, regulate gene expression by binding to the 3' untranslated region (3'-UTR) of specific mRNAs. Increasing evidence suggests that miRNAs are differently expressed in diseases associated with vascular neogenesis and play a crucial role in disease-related vascular neogenesis. However, current studies are not sufficient and further experimental studies are needed to validate and establish the relationship between miRNAs and diseases associated with vascular neogenesis, and to determine the specific role of miRNAs in vascular development pathways. To better treat vascular neogenesis in diseases such as RA, we need additional studies on the role of miRNAs and their target genes in vascular development, and to provide more strategic references. In addition, future studies can use modern biotechnological methods such as proteomics and transcriptomics to investigate the expression and regulatory mechanisms of miRNAs, providing a more comprehensive and in-depth research basis for the treatment of related diseases such as RA.

A survey exploring the nexus of psychological traits, nature connection, and quality of life among patients with rheumatoid arthritis

Background

As the recognition of psychological factors in chronic illness management grows, this study examined the interplay of psychological traits - grit, self-efficacy, resilience, and nature-relatedness - and their collective impact on the Quality of Life (QoL) among patients with rheumatoid arthritis (RA) in Malaysia.

Methods

A cross-sectional study was conducted among 222 patients with RA at a private hospital in Malaysia. Utilizing validated scales, including the Connor-Davidson Resilience Scale, Short Grit Scale, Nature Relatedness Scale, and Arthritis Self Efficacy Scale, data were collected. Pearson Product-moment Correlation analyses assessed the relationships between variables, and a multiple mediation analysis explored the mediating effects of resilience, grit, and self-efficacy on the relationship between nature-relatedness and QoL.

Findings

Of the 222 participants (86% female, mean age = 56.03, S.D. = 13.42), the analysis revealed a significant mediating role of resilience in the relationship between nature-relatedness and QoL among RA patients (b = -.117, SE = .042, 95% BCa CI [-.208, -.046]). Although grit and self-efficacy positively correlated with QoL, they did not serve as significant mediators in the nature-relatedness - QoL relationship. This highlights the pivotal role of building a sense of resiliency among patients with RA.

Interpretation

Individuals with RA are not only resilient in terms of their psychological traits such as grit, self-efficacy, and general resilience but also exhibit resilience in their connection and interaction with the natural environment (nature-relatedness). This holistic concept recognizes that fostering resilience in both psychological aspects and the context of one's environment is crucial for promoting overall well-being, particularly in the management of chronic illnesses like RA. It emphasizes the interconnectedness of psychological factors and environmental engagement in contributing to an individual's ability to cope and thrive despite health challenges.

Evaluation of the efficacy and safety of a herbal formulation for rheumatoid arthritis - A non-inferiority randomized controlled trial

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a diverse disease characterized by a variable, progressive course of articular and extra-articular symptoms that are linked with pain, disability, and mortality. The exact cause of rheumatoid arthritis is still being investigated, and there is no cure for this debilitating, persistent, painful disease. Qurs-e-Mafasil, a herbal Unani preparation, is regarded as a potent treatment for Waja'al-Mafasil, a condition clinically similar to rheumatoid arthritis, but scientific evidence is scarce.

AIM OF THE STUDY

This study aimed to assess the non-inferiority of Qurs-e-Mafasil compared to celecoxib in the treatment of patients with rheumatoid arthritis.

MATERIALS AND METHODS

This randomized controlled trial was conducted on seventy patients diagnosed with rheumatoid arthritis between the ages of 35 and 55 years. The participants were randomly allocated in a ratio of 3:2, with 42 participants in the test group and 28 participants in the control group. The test group was administered 2 tablets (each having 500 mg) of Qurs-e-Mafasil, while the control group was administered 1 capsule of Celecoxib 100 mg. Both medications were delivered for four weeks. The primary outcome measure was European League Against Rheumatism (EULAR) response criteria based on Disease Activity Score-28 (DAS28) assessed before and after therapy, whereas the secondary outcome measure was the change in joint pain severity as determined by a 100 mm Visual Analog Scale (VAS) at baseline and each follow-up. The safety of the interventions was evaluated based on adverse event monitoring at each follow-up and laboratory tests including hemogram, Liver Function Tests (LFTs), Kidney Function Tests (KFTs), and a complete urine examination performed at baseline and after four weeks of treatment.

RESULTS

The per-protocol analysis was done on 50 participants (30 in test group and 20 in control group) who completed the study duration. Thus, at the conclusion of the trial, participants in the test and control groups had either a moderate or no response based on EULAR response criteria. The odds ratio for no response versus moderate response between the test and the control groups was 0.71 (95% CI: 0.20-2.55) with p = 0.744. Moreover, the observed mean differences in VAS scores between the test and the control groups at 1st, 2nd, 3rd, and final follow-up were -0.33 (95% CI: -6.65 to 5.99, p = 0.916), 0.50 (95% CI: -5.63 to 6.63, p = 0.870), 2.42 (95% CI: -2.95 to 7.78, p = 0.370), and 3.00 (95% CI: -1.82 to 7.84, p = 0.219), respectively.

CONCLUSIONS

The differences in primary and secondary outcomes between the two groups indicate that Qurs-e-Mafāsil, a herbal Unani formulation containing Zingiber officinale Roscoe rhizome, Colchicum luteum Baker root, Piper nigrum L. fruit, and Withania somnifera (L.) Dunal. root, is comparable to celecoxib in the treatment of rheumatoid arthritis.

Immunomodulatory Nanoparticles for Modulating Arthritis Flares

Disease-modifying drugs have improved the treatment for autoimmune joint disorders, such as rheumatoid arthritis, but inflammatory flares are a common experience. This work reports the development and application of flare-modulating poly(lactic-co-glycolic acid)-poly(ethylene glycol)-maleimide (PLGA-PEG-MAL)-based nanoparticles conjugated with joint-relevant peptide antigens, aggrecan70-84 and type 2 bovine collagen256-270. Peptide-conjugated PLGA-PEG-MAL nanoparticles encapsulated calcitriol, which acted as an immunoregulatory agent, and were termed calcitriol-loaded nanoparticles (CLNP). CLNP had a ∼200 nm hydrodynamic diameter with a low polydispersity index. In vitro, CLNP induced phenotypic changes in bone marrow derived dendritic cells (DC), reducing the expression of costimulatory and major histocompatibility complex class II molecules, and proinflammatory cytokines. Bulk RNA sequencing of DC showed that CLNP enhanced expression of Ctla4, a gene associated with downregulation of immune responses. In vivo, CLNP accumulated in the proximal lymph nodes after intramuscular injection. Administration of CLNP was not associated with changes in peripheral blood cell numbers or cytokine levels. In the collagen-induced arthritis and SKG mouse models of autoimmune joint disorders, CLNP reduced clinical scores, prevented bone erosion, and preserved cartilage proteoglycan, as assessed by high-resolution microcomputed tomography and histomorphometry analysis. The disease protective effects were associated with increased CTLA-4 expression in joint-localized DC and CD4+ T cells but without generalized suppression of T cell-dependent immune response. The results support the potential of CLNP as modulators of disease flares in autoimmune arthropathies.

How to treat chronic pain in rheumatic and musculoskeletal diseases (RMDs) - A pharmacological review

INTRODUCTION

Chronic pain is a common symptom of rheumatic diseases that impacts patients' quality of life. While non-pharmacological approaches are often recommended as first-line treatments, pharmacological interventions are important for pain management. However, the effectiveness and safety of different pharmacological treatments for chronic pain in rheumatic diseases are unclear.

METHODS

This review critically synthesizes the current evidence base to guide clinicians in selecting appropriate pharmacological treatments for their patients, considering the expected benefits and potential risks and side effects.

RESULTS

For osteoarthritis, nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, opioids, and antidepressants are commonly used, with NSAIDs being the most recommended. In addition, topical agents, such as topical NSAIDs, are recommended for localized pain relief. For fibromyalgia, amitriptyline, serotonin and noradrenaline reuptake inhibitors (SNRIs), and gabapentinoids are commonly used, with SNRIs being the most recommended. For back pain, nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, opioids are used only for acute of flare-up pain, whereas neuropathic pain drugs are only used for chronic radicular pain. For inflammatory rheumatic diseases, disease-modifying antirheumatic drugs (DMARDs) and biological agents are recommended to slow disease progression and manage symptoms.

CONCLUSION

While DMARDs and biological agents are recommended for inflammatory rheumatic diseases, pharmacological treatments for other rheumatic diseases only alleviate symptoms and do not provide a cure for the underlying condition. The use of pharmacological treatments should be based on the expected benefits and evaluation of side effects, with non-pharmacological modalities also being considered, especially for fibromyalgia.

Reprint of "Residual pain in rheumatoid arthritis: Is it a real problem?"

Pain is a significant issue in rheumatoid arthritis (RA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.

Residual pain in rheumatoid arthritis: Is it a real problem?

Pain is a significant issue in rheumatoid arthritis (RA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.

"Shikonin inhibits microglia activation and reduces CFA-induced mechanical hyperalgesia in an animal model of pain"

Shikonin is an ointment produced from Lithospermun erythrorhizon which has been used in traditional medicine both in Europe and Asia for wound healing and is associated with anti-inflammatory properties. The goal of this work is to assess the analgesic properties of Shikonin in the CFA-induced inflammation model of pain. Rats were subjected to inflammation of the hind paw by CFA injection with a preventive injection of Shikonin and compared to either a control group or to a CFA-inflamed group with the vehicle drug solution. Inflammation of the hind paw by CFA was assessed by measurement of the dorsal to plantar diameter. Mechanical thresholds were established by means of the Von Frey filaments which are calibrated filaments that exert a defined force. Finally, the spinal cord of the studied animals was extracted to analyse the microglia population through immunohistochemistry using the specific marker Iba-1. Our results show that Shikonin reduces the paw oedema caused by CFA inflammation. Subsequently, there is a concomitant restoration of the mechanical thresholds reduced by CFA hind paw injection. Additionally, spinal microglia is activated after CFA-induced inflammation. Our results show that microglia is inhibited by Shikonin and has concomitant restoration of the mechanical thresholds. Our findings demonstrate for the first time that Shikonin inhibits microglia morphological changes and thereby ameliorates pain-like behaviour elicited by mechanical stimulation.

Pain profile and opioid medication use in patients with idiopathic inflammatory myopathies

OBJECTIVES

Pain is commonly reported in people living with myositis. This study assesses the presence of pain in the subtypes of myositis as well as the frequency of opioid and non-opioid pain medication use.

METHODS

A survey was developed and distributed by Myositis Support and Understanding, a patient-led advocacy organization, to members of its group. Multivariate logistic regression analysis and chi-squared tests were performed.

RESULTS

A total of 468 participants completed the survey. A total of 423 participants (DM n = 183, PM n = 109 and IBM n = 131) were included, based on reported diagnosis, for final analysis. Some 91.5% of myositis participants reported current or past pain, with 99% attributing their pain to myositis. There was a lower likelihood of pain in participants aged >60 years [odds ratio (OR) 0.2, 95% confidence interval (CI) 0.1, 0.6, P = 0.003]. The percentage of participants reporting pain was statistically different based on myositis type (DM 97.2%, IBM 80.9% and PM 94.5%, P < 0.001), with a higher likelihood of pain in DM compared with IBM (OR 3.7, 95% CI 1.3, 10.2, P = 0.011). There was a lower likelihood of pain in participants aged >60 years (OR 0.2, 95% CI 0.1, 0.6, P = 0.003). Of the 387 participants reporting pain, 335 reported using pain medications (69% prescribed opioids). Male sex, age >60 years and myositis subtype were not associated with likelihood of non-opioid use.

CONCLUSION

Pain is a commonly reported symptom in myositis with variable treatment strategies, including opioid medications. This study highlights the importance of addressing pain as part of myositis treatment as well as the need for future studies understanding treatment effectiveness.

The Neuroimmune Interplay in Joint Pain: The Role of Macrophages

Chronic pain associated with joint disorders, such as rheumatoid arthritis (RA), osteoarthritis (OA) and implant aseptic loosening (AL), is a highly debilitating symptom that impacts mobility and quality of life in affected patients. The neuroimmune crosstalk has been demonstrated to play a critical role in the onset and establishment of chronic pain conditions. Immune cells release cytokines and immune mediators that can activate and sensitize nociceptors evoking pain, through interaction with receptors in the sensory nerve terminals. On the other hand, sensory and sympathetic nerve fibers release neurotransmitters that bind to their specific receptor expressed on surface of immune cells, initiating an immunomodulatory role. Macrophages have been shown to be key players in the neuroimmune crosstalk. Moreover, macrophages constitute the dominant immune cell population in RA, OA and AL. Importantly, the targeting of macrophages can result in anti-nociceptive effects in chronic pain conditions. Therefore, the aim of this review is to discuss the nature and impact of the interaction between the inflammatory response and nerve fibers in these joint disorders regarding the genesis and maintenance of pain. The role of macrophages is highlighted. The alteration in the joint innervation pattern and the inflammatory response are also described. Additionally, the immunomodulatory role of sensory and sympathetic neurotransmitters is revised.

A 30-Day Adjunct Wellness Intervention for the Management of Extra-Articular Symptoms of Rheumatoid Arthritis: A Formative Study

Individuals with rheumatoid arthritis (RA) continually fall short of treatment targets using standard drug therapies alone. There is growing evidence that emphasizing physical and mental wellness is equally crucial for improving functioning among people with RA. The purpose of this formative study is to examine the feasibility of offering the wellness-based intervention (“KickStart30”) in patients with RA. Thirteen individuals with RA on targeted immune modulators (a biologic or JAK inhibitor) enrolled in the KickStart30 program. Participants completed self-report measures of RA-specific disability (eg, pain) and other functional areas (eg, mood) in a pre- versus post- intervention design. Paired samples t-tests (and Related-Samples Wilcoxon Signed Rank Tests for non-normal distributions) detected statistically significant results for 10 of 12 measures, including reductions in pain (M = 4.54 to M = 3.54; p = .025; BPI), functional disability (M = 0.94 to M = 0.73, p = .032; HAQ-II), cognitive and physical dysfunction (M = 25.46 to M = 13.54, p < .001; CPFQ), depressive symptoms (M = 9.31 to M = 5.54, p = .003; PHQ-9), anxiety (M= 5.69 to M = 3.23, p = .005; GAD-7), insomnia (M = 11.62 to M = 17.32, p = .007; Note: higher scores on the SCI indicate less insomnia), stress-related eating (M = 75.46 to M = 84.54, p = .021; Note: higher scores on the EADES indicate less stress-related eating), along with significant increases in mindfulness (M = 62.54 to M = 67.85, p = .040; MAAS), mental wellness (M = 4.46 to M = 5.69; HERO), and well-being (M_d = 8.00 to M_d = 5.00, p = .004; WHO-5). All significant measures had medium to large effect sizes (Cohen's d). The study gives preliminary support for the possibility that the adjunct intervention may have an effect.

Neuronal CRMP2 phosphorylation inhibition by the flavonoid, naringenin, contributes to the reversal of spinal sensitization and arthritic pain improvement

BACKGROUND

Rheumatoid arthritis patients usually suffer from arthritic chronic pain. However, due to an incomplete understanding of the mechanisms underlying autoimmune disorders, the management of arthritic pain is unsatisfactory. Here, we investigated the analgesic effect and underlying mechanism of the natural flavonoid naringenin (NAR) in collagen-induced arthritis (CIA) pain.

METHODS

NAR was injected (i.p.) once per day for 42 days after initial immunization, and rats were sacrificed on the 28th (the 21st day after final immunization, PID 21) and 42nd days (PID 35). The inflammatory factors, central sensitization indicators, and CRMP2 phosphorylation, as well as the anti-rheumatoid activity and analgesic effect of NAR, were further investigated.

RESULTS

We found that NAR decreased the arthritis score and paw swelling, as well as the mechanical and thermal pain. The immunofluorescence results also showed a dose dependent effect of NAR on reducing the expressions of spinal cFos, IBA-1, and GFAP on the 28th (PID 21) and 42nd day (PID 35). NAR decreased the phosphorylation of CRMP2 S522 and the expression of the kinase CDK5 in the spinal dorsal horn, but pCRMP2 Y479 was unchanged. In addition, CRMP2 was co-localized with NEUN, but not IBA-1 or GFAP, indicating the involvement of neural CRMP2 phosphorylation in CIA-related pain. Finally, CRMP2 S522 phosphorylation selective inhibitor (S)-lacosamide also alleviated arthritic pain.

CONCLUSIONS

Taken together, our results demonstrate that NAR alleviates inflammation and chronic pain in CIA model, which might be related to its inhibition of neuronal CRMP2 S522 phosphorylation, potentially mitigating the central sensitization. Our study provide evidence for the potential use of NAR as non-opioid-dependent analgesia in arthritic pain.

Chronic Pain in Patients with Rheumatoid Arthritis

PURPOSE OF REVIEW

Chronic pain is highly prevalent in patients with rheumatoid arthritis (RA) and can cause various physical and psychological impairments. Unfortunately, the appropriate diagnosis of chronic pain syndromes in this population can be challenging because pain may be primary to RA-specific inflammation and/or secondary to other conditions, typically osteoarthritis (OA) and fibromyalgia (FM). This disparity further poses a clinical challenge, given that chronic pain can often be discordant or undetected with standard RA-specific surveillance strategies, including serological markers and imaging studies. In this review, we provide a robust exploration of chronic pain in the RA population with emphasis on epidemiology, mechanisms, and management strategies.

RECENT FINDINGS

Chronic pain associated with RA typically occurs in patients with anxiety, female sex, and elevated inflammatory status. Up to 50% of these patients are thought to have chronic pain despite appropriate inflammatory suppression, typically due to peripheral and central sensitization as well as secondary OA and FM. In addition to the standard-of-care management for OA and FM, patients with RA and chronic pain benefit from behavioral and psychological treatment options. Moreover, early and multimodal therapies, including non-pharmacological, pharmacological, interventional, and surgical strategies, exist, albeit with varying efficacy, to help suppress inflammation, provide necessary analgesia, and optimize functional outcomes. Overall, chronic pain in RA is a difficult entity for both patients and providers. Early diagnosis, improved understanding of its mechanisms, and initiation of early, targeted approaches to pain control may help to improve outcomes in this population.

Comparison of Efficacy of Ketoprofen and Ibuprofen in Treating Pain in Patients with Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

INTRODUCTION

Patients with rheumatoid arthritis (RA) or other rheumatic diseases say that pain and stiffness are symptoms affecting their quality of life. Ketoprofen and ibuprofen are the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation and manage mild-to-moderate pain. The aim of this new systematic review of the literature and meta-analysis of randomized controlled trials (RCTs) was to compare the clinical efficacy of ketoprofen and ibuprofen in patients with RA.

METHODS

The MEDLINE and EMBASE scientific databases were systematically searched from their inception to November 2020 to identify RCTs directly comparing the recommended therapeutic doses of oral ketoprofen (50-200 mg/day) with ibuprofen (600-1800 mg/day) for RA pain relief. The meta-analysis was made using the standardized mean differences (SMD) of each of the identified RCTs using a fixed effects model.

RESULTS

Four RCTs involving 456 patients met the inclusion criteria. The results of the meta-analysis showed a statistically significant difference in efficacy in favor of ketoprofen (0.33, 95% CI 0.14-0.52, p = 0.0005) at all point-estimates of the mean-weighted size effect. The heterogeneity test for the efficacy outcome (the hypothesis was χ2 = 3.57%, df = 3, p value = 0.31 and the chance of a test effect was 3.49, p = 0.0005) was not significant, and this was confirmed by a Higgins percentage of 16%. The studies included in the meta-analysis did not reveal any significant differences between the two drugs in terms of tolerability or safety.

CONCLUSIONS

The result of this meta-analysis shows that ketoprofen is more effective than ibuprofen in managing RA pain at therapeutic doses, thus supporting its use in clinical practice.

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.

Is central sensitization an important determinant of functional disability in patients with chronic inflammatory arthritides?

Background

Central sensitization (CS) is a condition characterized by a disproportionate response to pain stimuli. We sought to investigate the prevalence of CS in patients with inflammatory arthritides and its association with measures of disease activity and functional disability.

Methods

We conducted an observational retrospective study in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) patients. We administered to all the subjects in the study the CS inventory (CSI), a questionnaire that has been used for the diagnosis of CS. Demographic and clinical characteristics were collected as well as measures or disease activity [i.e. Simple Disease Activity Index, Disease Activity Score in PsA (DAPSA)] and functional disability [Health Assessment Questionnaire Disability Index (HAQ-DI)]. Patients with fibromyalgia were excluded from the analyses. The primary outcome measure was the presence of functional disability as assessed by HAQ-DI >1.

Results

We enrolled 150 patients with inflammatory arthritides (78 PsA and 72 RA). Prevalence of CS was observed in 35.3% of the overall sample (29% in RA, 42.9% in PsA). Binary logistic regressions showed a strong, independent and linear association between functional disability and CS in both PsA and RA patients. The strength of this association was greater in PsA than in RA.

Conclusion

CS is an important determinant of functional disability in patients with chronic inflammatory arthritides. PsA appeared to be more vulnerable to CS. In addition, in the presence of CS, DAPSA did not adequately capture the occurrence of functional disability. Therefore, special attention should be paid to PsA patients, in whom the concomitant diagnosis of CS should be routinely ruled out.

Role of joint damage, malalignment and inflammation in articular tenderness in rheumatoid arthritis, psoriatic arthritis and osteoarthritis

OBJECTIVES

To determine whether clinical tenderness can be considered a sign of inflammatory joint activity in patients with rheumatoid arthritis (RA), osteoarthritis (OA) or psoriatic arthritis (PsA) and to assess other possible factors associated with tenderness.

METHODS

Patients diagnosed with RA, PsA and OA underwent clinical and ultrasound examination of wrists and finger joints. Radiographs of the hands were scored for erosions, joint space narrowing (JSN), osteophytes and malalignment. A binary damage score (positive if ≥1 erosion, JSN and/or presence of malalignment) was calculated. Differences in grey scale signs of synovitis and power Doppler (PD) between tender non-swollen (TNS) versus non-tender non-swollen (NTNS) joints were calculated. Disease duration was assessed,<2 years was regarded as early and >5 years as long-standing arthritis.

RESULTS

In total, 34 patients (9 early and 14 long-standing) from patients with RA, 31 patients (7 early and 15 long-standing) with PsA and 30 with OA were included. We found equal frequencies of PD signal between TNS and NTNS joints in RA (p=0.18), PsA (p=0.59) or OA (p=0.96). However, PD had a significant association with tenderness in early arthritis both in RA (p=0.02) and in PsA (p=0.02). The radiographic damage score showed significant association with tenderness in RA (p<0.01), PsA (p<0.01) and OA (p=0.04).

CONCLUSION

Tenderness might not always be a sign of active inflammation in RA, PsA and OA. While tenderness in early arthritis may be more related to inflammation, established disease is better explained by joint damage and malalignment.

Pain Mechanism in Rheumatoid Arthritis: From Cytokines to Central Sensitization

Pain is the most common symptom in patients with rheumatoid arthritis (RA). Although in recent years, through the implementation of targeted treatment and the introduction of disease-modifying antirheumatic drugs (DMARDs), the treatment of RA patients has made a significant progress, a large proportion of patients still feel pain. Finding appropriate treatment to alleviate the pain is very important for RA patients. Current research showed that, in addition to inflammation, RA pain involves peripheral sensitization and abnormalities in the central nervous system (CNS) pain regulatory mechanisms. This review summarized the literature on pain mechanisms of RA published in recent years. A better understanding of pain mechanisms will help to develop new analgesic targets and deploy new and existing therapies.

Unacceptable pain in the BARFOT inception cohort of patients with rheumatoid arthritis: a long-term study

Objectives: Pain is the most common and troublesome complaint in rheumatoid arthritis (RA). This study aimed to assess the prevalence and clinical implications of unacceptable pain in an inception cohort of patients with RA. Method: This study followed 477 patients from the BARFOT (Better Anti-Rheumatic FarmacOTherapy) early RA cohort for 15 years. Unacceptable pain was defined as ≥ 40 mm on a visual analogue scale for pain, while tolerable pain denoted no pain or pain below this cut-off, according to the patient acceptable symptom state concept. Results: Unacceptable pain was frequent. At the 15 year follow-up visit, 34% had unacceptable pain. Patients with unacceptable pain had, compared with patients with tolerable pain, significantly more disease activity, worse patient global assessment, and worse function on the Health Assessment Questionnaire and Signals of Functional Impairment, but the degree of joint destruction was similar. Disease-modifying anti-rheumatic drug treatment was similar, but patients with unacceptable pain were more often treated with corticosteroids. At 15 years, patients with unacceptable pain who were in remission (33%) had less inflammation and better function than those not in remission, suggesting the presence of non-inflammatory causes of pain. Conclusions: In this cohort of patients with RA, pain was frequent and severe, with negative effects on experienced health and function. Unacceptable pain was frequent and occurred also in patients in remission, indicating that pain in RA is multifactorial and should always be regarded as an important concern in itself. The cause of pain should be recognized and treated appropriately.

Endoplasmic reticulum-mitochondria interplay in chronic pain: The calcium connection

Chronic pain is a debilitating condition that affects roughly a third to a half of the world's population. Despite its substantial effect on society, treatment for chronic pain is modest, at best, notwithstanding its side effects. Hence, novel therapeutics are direly needed. Emerging evidence suggests that calcium plays an integral role in mediating neuronal plasticity that underlies sensitization observed in chronic pain states. The endoplasmic reticulum and the mitochondria are the largest calcium repositories in a cell. Here, we review how stressors, like accumulation of misfolded proteins and oxidative stress, influence endoplasmic reticulum and mitochondria function and contribute to chronic pain. We further examine the shuttling of calcium across the mitochondrial-associated membrane as a mechanism of cross-talk between the endoplasmic reticulum and the mitochondria. In addition, we discuss how endoplasmic reticulum stress, mitochondrial impairment, and calcium dyshomeostasis are implicated in various models of neuropathic pain. We propose a novel framework of endoplasmic reticulum-mitochondria signaling in mediating pain hypersensitivity. These observations require further investigation in order to develop novel therapies for chronic pain.

The important role of central sensitization in chronic musculoskeletal pain seen in different rheumatic diseases

OBJECTIVE

This study explored the role of central sensitization (CS) pain in patients with various rheumatic diseases using the CS inventory (CSI).

METHODS

A total of 193 patients of mean age 50.72 ± 9.65 years were included; they were divided into four different groups in terms of their rheumatic diseases. Patients with rheumatoid arthritis (RA), spondyloarthropathy (SpA), osteoarthritis (OA), and fibromyalgia syndrome (FMS) were evaluated in tertiary care rheumatology/pain medicine settings. Disease duration and activity, the Bath Ankylosing Spondylitis Disease Activity Index, the Disease Activity Score-28, and pain severity (evaluated using a visual analog scale) were assessed, and the Turkish version of the CSI administered.

RESULTS

CS syndromes were present in almost half the patients (45% of SpA, 41% of RA, 62% of OA, and 94% of FMS patients). We found no significant relationship between disease activity and the CSI-A scores in SpA or RA patients (p = 0.731 and p = 0.390, respectively). As expected, the CSI-A scores were highest in the FMS group (p = 0.000), but were similar in the other groups (p < 0.05). CS-related syndromes (CSI-B conditions) were present at similar frequencies in the RA, SpA, and OA groups, but were less common in the FMS group (p = 0.000).

CONCLUSIONS

The CSI usefully detects CS pain in patients with rheumatic diseases. Treatment of such pain can enhance the quality of daily life in patients with rheumatic diseases.Key Point• Central sensitization pain is common in patients with rheumatic diseases including rheumatoid arthritis, spondyloarthropathies, and osteoarthritis.

The Relation Between Disease Activity, Patient-Reported Outcomes, and Grip Force Over Time in Early Rheumatoid Arthritis

Objective

The objective of this study is to identify early predictors of future reduced grip force in patients with rheumatoid arthritis (RA) and to identify early predictors of grip force over time.

Methods

In a structured follow‐up of an inception cohort of patients with early RA, average grip force values of the dominant hand were evaluated and compared with the expected based on age‐ and sex‐specific reference values. Potential predictors of reduced grip force (less than 50% of expected) at 5 years were examined using logistic regression. Differences in percentage of expected grip force values over the study period and differences in change over time, by baseline disease parameters, were estimated using mixed linear‐effects models.

Results

Among 200 patients with early RA, 44% had reduced grip force 5 years after diagnosis. Baseline characteristics that predicted reduced grip force at 5 years included high scores for the Health Assessment Questionnaire Disability Index (odds ratio 1.54 per SD; 95% confidence interval 1.13‐2.11), high scores for pain and patient global assessment, and low grip force. C‐reactive protein levels, the erythrocyte sedimentation rate, the 28‐joint Disease Activity Score (DAS28), rheumatoid factor, anti–cyclic citrullinated peptide antibodies, joint counts, and synovitis of individual joints in the dominant upper extremity did not predict reduced grip force. Patients with baseline synovitis of the wrist or metacarpophalangeal joints or patients with a high DAS28 had lower estimated grip force at inclusion but also greater improvement of grip force over time.

Conclusion

Patient‐reported outcomes predicted reduced grip strength 5 years after diagnosis. This underlines the prognostic importance of disability in early RA. Joint counts and synovitis in individual joints may change rapidly in early RA and appear to be less predictive of long‐term hand function.

Types of pain and their psychosocial impact in women with rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease predominantly affecting middle-aged women. Very commonly, pain is a manifestation of active disease and because untreated RA can result in joint deformities, the current evaluation of pain has largely focused on inflammation. In addition, treatment has centered on the premise of reducing disease activity with the hopes of halting worsening damage, preventing future deformities, and ultimately providing pain relief for the patient. Yet research shows that all patients with RA, but women in particular, often suffer from increased mechanical pain and fibromyalgia, as well as anxiety, depression, sleep disturbances, sexual dysfunction, and disability, which add to the burden of the illness. Determining and addressing alternative pain triggers as well as understanding the psychosocial burden of RA is key in treating patients, especially in those who may not improve with traditional pharmacotherapy.

Health Care Effect of Disease-Modifying Antirheumatic Drug Use on Patients with Rheumatoid Arthritis

BACKGROUND

Disease-modifying antirheumatic drugs (DMARDs) are recommended as the standard of care for patients with rheumatoid arthritis (RA) due to their ability to reduce pain and disability; however, DMARD use is low in some subgroups of the RA population.

OBJECTIVE

To identify characteristics associated with DMARD use in the overall cohort of patients with RA and newly diagnosed RA patients.

METHODS

This retrospective observational study used claims from a large national health plan. Use of DMARDs was measured according to the Healthcare Effectiveness Data and Information Set (HEDIS) as the proportion of patients with RA receiving DMARDs. Following HEDIS measure technical specifications, we identified patients aged 18-89 years with continuous enrollment during 2014 (measurement year) with ≥ 2 claims for RA outpatient visits and/or discharges on different dates between January and November 2014. Additionally, we identified a subset of patients newly diagnosed with RA in 2014 based on absence of any claims for RA or DMARDs in 2013. Descriptive analyses and bivariate associations were used to compare demographic and clinical characteristics of patients with RA with or without DMARD use in 2014. Health care resource utilization (HCRU) and costs were compared in 2014 for patients enrolled in Medicare Advantage Prescription Drug (MAPD) plans during both 2014 and 2015. Regression models were used to evaluate patient and provider characteristics associated with DMARD use in 2014 and the effect on HCRU and costs.

RESULTS

Among the 33,880 patients identified with RA in 2014, most patients received a DMARD (75.2%); 29.4% of patients newly diagnosed with RA had been treated with DMARDs in 2014. Patients with DMARD use, on average, were younger (aged 67 years ± 10.7 vs. 69 years ± 10.7) and healthier (Deyo-Charlson Comorbidity Index [DCCI] 2.4 ± 1.9 vs. 2.6 ± 2.1) and included a greater proportion of women (75.9% vs. 71.0%) than those with no DMARD use (P < 0.0001). Use of DMARDs (P < 0.0001) was associated with 14.5% fewer hospitalizations and 18.0% fewer emergency department visits. Although total costs increased by 15.0% with use of DMARDs, when the cost of DMARDs was excluded, the total cost decreased by 13.7% (P < 0.0001). Female gender (32.2%), higher claims-based index for RA severity score (47.0%), higher RxRisk-V score (26.7%), visit to a rheumatologist (34.3%), and use of glucocorticoids (17.7%) increased the odds of DMARD use (P < 0.0001). Use of certain classes of medication, such as nonsteroidal anti-inflammatory drugs (12.3%), opioids (19.5%), antidepressants (20.0%), muscle relaxants (12.5%), and anticonvulsants (15.5%), were associated with lower use of DMARDs (P < 0.0001).

CONCLUSIONS

We found significant differences in demographic and clinical characteristics between patients with and without DMARD use, which can potentially inform treatment decisions regarding DMARD use as deemed necessary by the provider. Future research should investigate the reasons for lack of treatment.

DISCLOSURES

This study was supported by funding from Eli Lilly to Humana as a collaborative research project involving employees of both companies. Boytsov, Saverno, Zhang, and Gaich are employees of Eli Lilly. Nair, Bhattacharya, Abbott, and Dixon are employees of Humana, which received funding from Eli Lilly to complete this research.

Efficacy of a Web-Based Self-Management Enhancing Program for Patients with Rheumatoid Arthritis: Explorative Randomized Controlled Trial

Background

Web-based self-management enhancing programs have the potential to support patients with rheumatoid arthritis (RA) in their self-management; for example, improve their health status by increasing their self-efficacy or taking their prescribed medication. We developed a Web-based self-management enhancing program in collaboration with RA patients and professionals as co-designers on the basis of the intervention mapping framework. Although self-management programs are complex interventions, it is informative to perform an explorative randomized controlled trial (RCT) before embarking on a larger trial.

Objective

This study aimed to evaluate the efficacy of a Web-based self-management enhancing program for patients with RA and identify outcome measures most likely to capture potential benefits.

Methods

A multicenter exploratory RCT was performed with an intervention group and a control group. Both groups received care as usual. In addition, the intervention group received 12 months of access to a Web-based self-management program. Assessment occurred at baseline, 6 months, and 12 months. Outcome measures included self-management behavior (Patient Activation Measurement, Self-Management Ability Scale), self-efficacy (Rheumatoid Arthritis task-specific Self-Efficacy, Perceived Efficacy in Patient-Physician Interaction), general health status (RAND-36), focus on fatigue (Modified Pain Coping Inventory for Fatigue), and perceived pain and fatigue (Numeric Rating Scales). A linear mixed model for repeated measures, using the intention-to-treat principle, was applied to study differences between the patients in the intervention (n=78) and control (n=79) groups. A sensitivity analysis was performed in the intervention group to study the influence of patients with high (N=30) and low (N=40) use of the intervention.

Results

No positive effects were found regarding the outcome measurements. Effect sizes were low.

Conclusions

Based on these results, it is not possible to conclude on the positive effects of the intervention or to select outcome measures to be regarded as the primary/main or secondary outcomes for a future trial. A process evaluation should be performed to provide more insight into the low compliance with and effectiveness of the intervention. This can determine for whom this sort of program will work and help to fine-tune the inclusion criteria.

Trial Registration

Netherlands Trial Register NTR4871; https://www.trialregister.nl/trial/4726

Pain, balance, grip strength and gait parameters of older adults with and without post-chikungunya chronic arthralgia

OBJECTIVE

To compare the levels of pain, grip strength, balance and gait in older adults with and without post-Chikungunya chronic arthralgia (PCCA).

METHODS

Sixty-two older adults, 30 with and 32 without PCCA participated in the study. Pain level was assessed using a Visual Analogue Scale (VAS). Gait during a 10-m walk was assessed using inertial sensors. Semi-static balance was assessed during an eyes-closed bipedal balance test on a force platform, and grip strength was assessed using a hand dynamometer.

RESULTS

Participants with PCCA presented severe levels of pain (VAS > 7.5), poorer balance, lower grip strength, walked slower, with lower cadence and stride length and higher stride time and stride length variability than participants without PCCA (P < 0.001 for all variables).

CONCLUSIONS

Older adults with PCCA had high levels of pain, impaired balance and gait and lower grip strength compared to older adults without PCCA.

High prevalence of widespread pain in women with early rheumatoid arthritis

OBJECTIVES

The aim of the study was to determine the prevalence of widespread pain (WP) in women with early rheumatoid arthritis (RA) and to compare physical function, activity limitations, health-related quality of life, mental distress, and disease activity between women with WP and non-widespread pain (NWP).

METHOD

This cross-sectional study included 102 women with early RA. Participants were provided with self-reported questionnaires quantifying activity limitations, physical activity, pain intensity, health-related quality of life, and fatigue. Hand-grip force, muscle function test of the lower extremities, erythrocyte sedimentation rate, and number of tender and swollen joints were assessed.

RESULTS

One-third (35.9%) of the women fulfilled the American College of Rheumatology criteria for WP 20 months after disease onset. Women with RA + WP had significantly higher 28-joint Disease Activity Score (DAS28) (p = 0.004), number of tender joints (p = 0.001), pain intensity (p < 0.001), fatigue (p < 0.001), Health Assessment Questionnaire score (p < 0.001), and Hospital Anxiety and Depression Scale - Depression (p = 0.001). Furthermore, women with RA + WP showed significantly worse global health (p < 0.001) and physical health (36-item Short Form Health Survey - Physical Component Summary) (p < 0.001). The hand-grip force was found to be significantly reduced (p = 0.001), as was the muscle function of the lower extremities (p < 0.001), for women with RA + WP compared to women with RA + NWP. After adjustment for inflammatory joint disease, the significant differences between the groups remained.

CONCLUSION

A significant group of women with early RA experience WP with a high DAS28 and increased pain intensity level. These women display severe muscle function deficiency in clinical examinations, and report general activity limitations and low psychological and physical health, despite an absence of or low objective signs of inflammation.

Chronic Pain in Inflammatory Arthritis: Mechanisms, Metrology, and Emerging Targets-A Focus on the JAK-STAT Pathway

Chronic pain is nowadays considered not only the mainstay symptom of rheumatic diseases but also "a disease itself." Pain is a multidimensional phenomenon, and in inflammatory arthritis, it derives from multiple mechanisms, involving both synovitis (release of a great number of cytokines) and peripheral and central pain-processing mechanisms (sensitization). In the last years, the JAK-STAT pathway has been recognized as a pivotal component both in the inflammatory process and in pain amplification in the central nervous system. This paper provides a summary on pain in inflammatory arthritis, from pathogenesis to clinimetric instruments and treatment, with a focus on the JAK-STAT pathway.

Influence of Morphine and Naloxone on Pain Modulation in Rheumatoid Arthritis, Chronic Fatigue Syndrome/Fibromyalgia, and Controls: A Double-Blind, Randomized, Placebo-Controlled, Cross-Over Study

BACKGROUND

Impaired pain inhibitory and enhanced pain facilitatory mechanisms are repeatedly reported in patients with central sensitization pain. However, the exact effects of frequently prescribed opioids on central pain modulation are still unknown.

METHODS

A randomized, double-blind, placebo-controlled cross-over trial was carried out. Ten chronic fatigue syndrome (CFS)/fibromyalgia (FM) patients, 11 rheumatoid arthritis (RA) patients and 20 controls were randomly allocated to the experimental (10 mg morphine or 0.2 mg/mL Naloxone) and placebo (2 mL Aqua) group. Pressure pain thresholds (PPTs) and temporal summation at the Trapezius and Quadriceps were assessed by algometry. Conditioned pain modulation (CPM) efficacy and deep tissue pain pressure were assessed by adding ischemic occlusion at the opposite upper arm.

RESULTS

Deep tissue pain pressure was lower and temporal summation higher in CFS/FM (P = 0.002 respectively P = 0.010) and RA patients (P = 0.011 respectively P = 0.047) compared to controls at baseline. Morphine had only a positive effect on PPTs in both patient groups (P time = 0.034). Accordingly, PPTs increased after placebo (P time = 0.015), and no effects on the other pain parameters were objectified. There were no significant effects of naloxone nor nocebo on PPT, deep tissue pain, temporal summation or CPM in the control group.

CONCLUSIONS

This study revealed anti-hyperalgesia effects of morphine in CFS/FM and RA patients. Nevertheless, these effects were comparable to placebo. Besides, neither morphine nor naloxone influenced deep tissue pain, temporal summation or CPM. Therefore, these results suggest that the opioid system is not dominant in (enhanced) bottom-up sensitization (temporal summation) or (impaired) endogenous pain inhibition (CPM) in patients with CFS/FM or RA.

The dual regulation of substance P-mediated inflammation via human synovial mast cells in rheumatoid arthritis

BACKGROUND

Neural pathways are thought to be directly involved in the pathogenesis of rheumatoid arthritis (RA). Although synovial mast cells (MCs) are activated by substance P (SP), the role of MCs in neural pathways in RA remains unknown. The aims of this study were to investigate 1) whether tachykinins are produced by synovial MCs and whether production differs in RA and osteoarthritis (OA) patients, and 2) what is the responsible receptor for SP in synovial MCs.

METHODS

Synovial tissues were obtained from patients with RA or OA undergoing joint replacement surgery. Cultured synovium-derived MCs were generated by culturing dispersed synovial cells with stem cell factor. SP expression was investigated using immunofluorescence and enzyme immunoassays. Mas-related gene X2 (MrgX2) expression was reduced in human MCs using a lentiviral shRNA silencing technique.

RESULTS

SP expression was localized around the cell membrane in 41% (median) of the MCs in synovium from RA but in only 7% of that from OA, suggesting the activation of MCs. Synovial MCs expressed tachykinin (TAC) 1 mRNA, the expression of which was upregulated by the aggregation of FcɛRI or the addition of aggregated IgG. However, the released SP appeared to be rapidly degraded by MC chymase. Synovial MCs were activated with SP through MrgX2 to release histamine without producing proinflammatory cytokines.

CONCLUSIONS

Activated synovial MCs may rapidly degrade SP, which may downregulate the SP-mediated activation of synoviocytes in RA. On the other hand, SP activates MCs to induce inflammatory mediators, suggesting the dual regulation of SP-mediated inflammation by MCs in RA.

Emerging Roles for MAS-Related G Protein-Coupled Receptor-X2 in Host Defense Peptide, Opioid, and Neuropeptide-Mediated Inflammatory Reactions

Mast cells (MCs) are tissue-resident immune cells that contribute to host defense but are best known for their roles in allergic and inflammatory diseases. In humans, MCs are divided into two subtypes based on the protease content of their secretory granules. Thus, human lung MCs contain only tryptase and are known as MC_T, whereas skin MCs contain both tryptase and chymase and are known as MC_TC. Patients with severe asthma display elevated MCs in the lung, which undergo phenotypic change from MC_T to MC_TC. Although the human genome contains four Mas related G protein coupled receptor X (MRGPRX) genes, an important feature of MC_TC is that they selectively express MRGPRX2. It is activated by antimicrobial host defense peptides such as human β-defensins and the cathelicidin LL-37 and likely contributes to host defense. MRGPRX2 is also a receptor for the neuropeptide substance P, major basic protein, eosinophil peroxidase, opioids, and many FDA-approved cationic drugs. Increased expression of MRGPRX2 or enhanced downstream signaling likely contributes to chronic inflammatory diseases such as rosacea, atopic dermatitis, chronic urticaria, and severe asthma. In this chapter, I will discuss the expression profile and function of MRGPRX1-4 and review the emerging roles of MRGPRX2 on host defense, chronic inflammatory diseases, and drug-induced pseudoallergic reactions. I will also examine the novel aspects of MRGPRX2 signaling in MCs as it related to degranulation and review the mechanisms of its regulation.

YKL-40-Induced Inhibition of miR-590-3p Promotes Interleukin-18 Expression and Angiogenesis of Endothelial Progenitor Cells

YKL-40, also known as human cartilage glycoprotein-39 or chitinase-3-like-1, is a pro-inflammatory protein that is highly expressed in rheumatoid arthritis (RA) patients. Angiogenesis is a critical step in the pathogenesis of RA, promoting the infiltration of inflammatory cells into joints and providing oxygen and nutrients to RA pannus. In this study, we examined the effects of YKL-40 in the production of the pro-inflammatory cytokine interleukin-18 (IL-18), and the stimulation of angiogenesis and accumulation of osteoblasts. We observed that YKL-40 induces IL-18 production in osteoblasts and thereby stimulates angiogenesis of endothelial progenitor cells (EPCs). We found that this process occurs through the suppression of miR-590-3p via the focal adhesion kinase (FAK)/PI3K/Akt signaling pathway. YKL-40 inhibition reduced angiogenesis in in vivo models of angiogenesis: the chick embryo chorioallantoic membrane (CAM) and Matrigel plug models. We report that YKL-40 stimulates IL-18 expression in osteoblasts and facilitates EPC angiogenesis.

Enhancement of CCL2 expression and monocyte migration by CCN1 in osteoblasts through inhibiting miR-518a-5p: implication of rheumatoid arthritis therapy

Cysteine-rich 61 (Cyr61 or CCN1), a secreted protein from the CCN family, is an important proinflammatory cytokine. Migration and infiltration of mononuclear cells to inflammatory sites play a critical role in the pathogenesis of rheumatoid arthritis (RA). Monocyte chemoattractant protein-1 (MCP-1/CCL2) is the key chemokine that regulates migration and infiltration of monocytes. Here, we examined the role of CCN1 in monocyte migration, and CCL2 expression in osteoblasts. We found higher levels of CCN1 and CCL2 in synovial fluid from RA patients compared with levels from non-RA controls. We also found that the CCN1-induced increase in CCL2 expression is mediated by the MAPK signaling pathway and that miR-518a-5p expression was negatively regulated by CCN1 via the MAPK cascade. In contrast, inhibition of CCN1 expression with lentiviral vectors expressing short hairpin RNA ameliorated articular swelling, cartilage erosion, and infiltration of monocytes in the ankle joints of mice with collagen-induced arthritis. Our study describes how CCN1 promotes monocyte migration by upregulating CCL2 expression in osteoblasts in RA disease. CCN1 could serve as a potential target for RA treatment.

CCN1 Promotes VEGF Production in Osteoblasts and Induces Endothelial Progenitor Cell Angiogenesis by Inhibiting miR-126 Expression in Rheumatoid Arthritis

Angiogenesis is the formation of new capillaries from preexisting vasculature. The perpetuation of angiogenesis plays a critical role in the pathogenesis of various disease states including rheumatoid arthritis (RA). Cysteine-rich 61 (Cyr61 or CCN1) is an important proinflammatory cytokine in RA. Here, we investigated the role of CCN1 in angiogenesis associated with vascular endothelial growth factor (VEGF) production and osteoblasts. We found higher expression of CCN1 and VEGF in synovial fluid from RA patients compared with healthy controls. CCN1 induced VEGF expression in osteoblasts and increased endothelial progenitor cells (EPCs) angiogenesis by inhibiting miR-126 via the protein kinase C-alpha (PKC-α) signaling pathway. CCN1 knockdown inhibited angiogenesis in both in vitro and in vivo models. Inhibition of CCN1 expression with lentiviral vectors expressing short hairpin RNA (shRNA) ameliorated articular swelling, cartilage erosion, and angiogenesis in the ankle joint of mice with collagen-induced arthritis (CIA). Our study is the first to describe how CCN1 promotes VEGF expression in osteoblasts and increased EPCs angiogenesis in RA disease. CCN1 may serve as a potential target for RA treatment. © 2016 American Society for Bone and Mineral Research.

Osteopontin inhibition of miR-129-3p enhances IL-17 expression and monocyte migration in rheumatoid arthritis

BACKGROUND

Osteopontin (OPN) is an important proinflammatory cytokine in rheumatoid arthritis (RA). Levels of OPN have been shown to be significantly correlated with interleukin-17 (IL-17) production and expression of Th17 cells in the synovial fluid of RA patients. Here, we investigated the role of OPN in monocyte migration, IL-17 production and osteoblasts.

METHODS

OPN and IL-17 expression profiles in osteoarthritis (OA) and RA synovial fluid were determined by enzyme-linked immunosorbent assay (ELISA). The expression of the microRNA, miR-129-3p, in osteoblasts was analyzed by real-time quantitative polymerase chain reaction (qPCR). Immunoreactive proteins were spotted by Western blotting. We used the collagen-induced arthritis (CIA) mouse model to investigate the role of OPN in monocyte migration during RA.

RESULTS

OPN and IL-17 expression were higher in RA synovial fluid as compared to OA samples. We also found that OPN promotes IL-17 expression in osteoblasts and thereby enhances monocyte migration via the Syk/PI3K/Akt signaling pathway. miR-129-3p expression was found to be negatively regulated by OPN via the Syk/PI3K/Akt signal cascade. In contrast, lentiviral vectors expressing short hairpin RNA inhibited OPN expression and ameliorated articular swelling, cartilage erosion and monocyte infiltration in the ankle joints of CIA mice.

CONCLUSION

To our knowledge, our study is the first to describe how OPN promotes monocyte migration by upregulating IL-17 expression in osteoblasts in RA disease.

SIGNIFICANCE

These findings indicate that OPN could serve as a potential therapeutic target for the treatment of RA.

Effect of Milnacipran on Pain in Patients with Rheumatoid Arthritis with Widespread Pain: A Randomized Blinded Crossover Trial

OBJECTIVE

Clinical trials have shown that serotonin norepinephrine reuptake inhibitors, such as milnacipran, decrease pain in noninflammatory pain conditions such as fibromyalgia and osteoarthritis. We examined the effect of milnacipran on self-reported pain intensity and experimental pain sensitivity among patients with rheumatoid arthritis (RA) with widespread pain and stable RA disease activity.

METHODS

In this double-blind, crossover study, patients with RA with widespread pain, receiving a stable treatment regimen, were randomized (by a random number generator) to receive milnacipran 50 mg twice daily or placebo for 6 weeks, followed by a 3-week washout and crossed over to the other arm for the remaining 6 weeks. The primary outcome was change in average pain intensity, assessed by the Brief Pain Inventory short form. The sample size was calculated to detect a 30% improvement in pain with power = 0.80 and α = 0.05.

RESULTS

Of the 43 randomized subjects, 41 received the study drug, and 32 completed the 15-week study per protocol. On a 0-10 scale, average pain intensity decreased by 0.39 (95% CI -1.27 to 0.49, p = 0.37) more points during 6 weeks of milnacipran treatment compared with placebo. In the subgroup of subjects with swollen joint count ≤ 1, average pain intensity decreased by 1.14 more points during 6 weeks of milnacipran compared with placebo (95% CI -2.26 to -0.01, p = 0.04). Common adverse events included nausea (26.8%) and loss of appetite (9.7%).

CONCLUSION

Compared with placebo, milnacipran did not improve overall, self-reported pain intensity among subjects with widespread pain receiving stable RA medications.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01207453.

Simultaneous determination of four secoiridoid and iridoid glycosides in rat plasma by ultra performance liquid chromatography-tandem mass spectrometry and its application to a comparative pharmacokinetic study

A simple, reliable and rapid ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of four secoiridoid (gentiopicroside, swertiamarin, sweroside) and iridoid glycosides (loganic acid), the bio-active ingredients in rat plasma. After liquid-liquid extraction, chromatographic separation was accomplished on a Shim-pack XR-ODS column with a mobile phase consisting of methanol and 0.1% formic acid in water. A triple quadrupole tandem mass spectrometry equipped with an electrospray ionization source was used as detector operating both in positive and negative ionization mode and operated by multiple-reaction monitoring scanning. The lower limits of quantitation were 0.25-30 ng/mL for all the analytes. Both intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (±15%). The mean extraction recoveries of analytes and internal standard (amygdalin) from rat plasma were all >71.4%. The validated method was successfully applied to a comparative pharmacokinetic study of four analytes in rat plasma between normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan and Gentiana macrophylla extract, respectively. Results showed significant differences in pharmacokinetic properties of the analytes among the different groups.

Is it necessary to strictly diagnose fibromyalgia syndrome in patients with chronic widespread pain?

The applicability of the American College of Rheumatology (ACR) 1990 and 2010 criteria for the diagnosis of fibromyalgia syndrome (FMS) was determined in 284 patients with chronic widespread pain (CWP) including those with regional and systemic painful disorders. On the basis of initial evaluation, patients were classified into three groups. Group 1, those without any comorbid disease (N = 105), group 2, those having regional non-inflammatory painful disorders (N = 104), and group 3, those with a diagnosis of an inflammatory rheumatic disease (N = 75). Overall, 65 % of the patients fulfilled the 1990 criteria, while 94 % of them fulfilled the 2010 criteria. Almost all of the patients (97 %) with CWP did meet at least one of the criteria set, regardless of whether they have accompanying painful disorders. Widespread pain index (WPI), symptom severity scale (SS), and fibromyalgia impact questionnaire (FIQ) scores were found to be significantly higher in the patients who satisfied the 1990 criteria than those who did not (P < 0.001). Tender point counts were found to be significantly correlated with WPI, SS, FIQ, and Beck depression inventory (BDI) scores (P < 0.001). The findings of the study support the suggestion that FMS is just a continuum of CWP, rather than a distinct diagnostic entity. As treatment of FMS is usually identical with that of CWP, strict diagnosis of FMS will provide little or no significance from the viewpoint of clinical practice. We suggest that future research should be directed toward classification of CWP to provide guidance to clinicians in selecting effective therapies.

Pain in systemic inflammatory rheumatic diseases

The sometimes intense, persistent and disabling pain associated with rheumatoid arthritis (RA) and spondyloarthritis frequently has a multifactorial, simultaneously central and peripheral origin, and it may be due to currently active inflammation or joint damage and tissue destruction caused by a previous inflammatory condition. The symptoms of inflammatory pain symptoms can be partially relieved by non-steroidal anti-inflammatory drugs, but many patients continue to experience moderate pain due to alterations in central pain regulation mechanisms, as in the case of the chronic widespread pain (CWP) characterising fibromyalgia. The importance of distinguishing CWP from inflammatory pain is underlined by the fact that drugs such as tumour necrosis factor inhibitors are expensive, and direct costs are higher in patients with concomitant CWP than in those without. The management of pain requires a combination approach that includes pharmacological analgesia, and biological and non-biological treatments because, although joint replacement surgery can significantly improve RA-related pain, it may only be available to patients with the most severe advanced disease.