Somatosensory perception and function of diffuse noxious inhibitory controls (DNIC) in patients suffering from rheumatoid arthritis

Immersive visualization of movement in patients with hemophilic ankle arthropathy. Multicenter, single-blind, randomized clinical trial

OBJECTIVE

To evaluate the efficacy of immersive movement observation in adult patients with haemophilic ankle arthropathy.

DESIGN

Multicentre, single-blind, randomized clinical trial.

SUBJECTS

48 patients with haemophilia.

METHODS

Patients were randomly allocated to 2 groups (180º immersive video-based visualization of movement and a control group with no intervention). Twenty-eight consecutive 15-min home sessions, 1 per day, of immersive visualization of ankle flexion-extension movement were carried out. Three evaluations were performed: pretreatment (T0), post-intervention (T1), and at 16 weeks' follow-up (T2). The primary variable was joint-pain intensity (visual analogue scale). The secondary variables were conditioned pain modulation (Conditioned Pain Modulation Index), pressure pain threshold (pressure algometer), range of motion (goniometry) and kinesiophobia (Tampa Scale of Kinesiophophia).

RESULTS

There were intergroup differences in pain intensity (F = 37.14; p < 0.001), conditioned pain modulation (F = 5.40; p = 0.006), and dorsal (F = 19.17; p < 0.001) and plantar (F = 9.27; p<0.001) ankle flexion. More than 50% of experimental group patients exhibited changes exceeding the minimum detectable change in pain intensity (MDC = 0.43), and the pressure pain threshold in the extensor carpi radialis longus muscle (MDC = 1.34) and malleolus (MDC = 4.93).

CONCLUSIONS

180º immersive video-based visualization of movement can improve the intensity of pain, conditioned pain modulation, and ankle range of motion in patients with haemophilic ankle arthropathy.

Safety and efficacy of myofascial release therapy in the treatment of patients with hemophilic ankle arthropathy. Single-blind randomized clinical trial

BACKGROUND

Hemophilia is characterized by degenerative joint damage. Patients with hemophilic arthropathy present joint damage, reduced range of motion, and decreased strength and functional capacity. Myofascial release therapy aims to decrease pain and improve tissue mobility and functionality.

OBJECTIVES

To evaluate the safety and efficacy of myofascial release therapy in patients with hemophilic ankle arthropathy.

METHOD

Single-blind randomized controlled trial. Fifty-eight adult patients with hemophilia were randomly allocated to the experimental group (myofascial release therapy with foam roller) or the control group (no intervention whatsoever). The daily home protocol of myofascial release therapy for the lower limbs using a foam roller lasted eight consecutive weeks. The primary variable was the safety of myofascial release therapy (weekly telephone follow-up). The secondary variables were pain intensity (visual analog scale), range of motion (goniometer), functional capacity (2-Minute Walk Test) and muscle strength (dynamometer), at baseline and at 8 and 10 weeks.

RESULTS

During the experimental phase, none of the patients in the experimental group developed ankle hemarthrosis. There were statistically significant changes in time*group interaction in ankle dorsal flexion (F[1.75] = 10.72; p < .001), functional capacity (F[1.16] = 5.24; p = .009) and gastrocnemius strength (F[2] = 26.01; p < .001). The effect size of the changes after the intervention was medium-large in pain intensity (d = -1.77), functional capacity (d = 1.34) and gastrocnemius strength (d = 0.76).

CONCLUSION

Myofascial release therapy is a safe form of physical therapy for patients with hemophilia. Myofascial release therapy can effectively complement prophylactic pharmacological treatment in patients with hemophilic arthropathy, improving range of motion in dorsal flexion, functional capacity and gastrocnemius strength.

"Inflammatory or non-inflammatory pain in inflammatory arthritis - How to differentiate it?"

Pain is a significant issue in rheumatoid arthritis (RA) and psoriatic arthritis (PSA) 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.

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.

Foam roller-based self-induced myofascial therapy in patients with hemophilic knee arthropathy: a multicenter, single-blind, randomized clinical study

BACKGROUND

Hemophilia is a congenital coagulopathy characterized by degenerative joint damage. Self-induced myofascial therapy aims to decrease pain and improve tissue mobility, functionality and proprioception.

AIM

The aim of this study was to evaluate the safety and efficacy of self-induced myofascial release in patients with hemophilic knee arthropathy.

DESIGN

This is a randomized clinical study.

SETTING

This study was carried out in different patient associations.

POPULATION

Fifty-two patients with hemophilia were included in the study.

METHODS

Patients were randomized to the experimental group (daily home protocol of foam roller-based self-induced myofascial therapy for 8 weeks) or the control group (no intervention). The variables were the frequency of hemarthrosis (self-reporting), pain intensity (visual analog scale), range of motion (goniometry) and muscle strength (dynamometry). All variables were evaluated at baseline, post-treatment and after a 10-week follow-up.

RESULTS

The patients included in the experimental group showed significant improvements in terms of a decrease in frequency of hemarthrosis (mean difference [MD]=-0.61; 95% confidence interval [CI]: -0.81; -0.41) and pain intensity (MD=-0.33; 95% CI: -0.48, -0.18), increased range of motion (MD=0.88; 95% CI: 0.39; 1.37), strength in quadriceps (MD=0.88; 95% CI: 0.39; 1.37). (MD=12.39; 95% CI: 3.44; 21.34) and hamstrings (MD=7.85; 95% CI: 0.60; 15.11). There were intergroup differences in the frequency of hemarthrosis (F=14.51; P<0.001), pain intensity (F=9.14; P<0.001) and range of motion (F=13.58; P<0.001).

CONCLUSIONS

Self-induced myofascial therapy can be an effective complementary technique in the treatment of patients with hemophilic arthropathy. Self-induced myofascial therapy can reduce the frequency of knee hemarthrosis in patients with hemophilia. This technique can improve pain intensity and range of motion in patients with hemophilic knee arthropathy.

CLINICAL REHABILITATION IMPACT

Hemophilic knee arthropathy is characterized by chronic pain, decreased range of motion, and periarticular muscle atrophy. Foam roller-based self-induced myofascial therapy can reduce the frequency of hemarthrosis and pain intensity and improve range of motion in patients with hemophilic arthropathy. Foam roller-based self-induced myofascial therapy is safe and effective in the treatment of patients with hemophilia. The inclusion of self-induced myofascial therapy exercises in the approach to degenerative joint pathologies may be an effective and safe treatment option.

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.

Disproportionate articular pain is a frequent phenomenon in rheumatoid arthritis and responds to treatment with sarilumab

OBJECTIVES

In some patients with RA, joint pain is more severe than expected based on the amount of joint swelling [referred to as disproportionate articular pain (DP)]. We assessed DP prevalence and the effects of sarilumab, an IL-6 inhibitor, on DP.

METHODS

Data from RA patients treated with placebo or 200 mg sarilumab in the phase 3 randomized controlled trials (RCTs) MOBILITY and TARGET, adalimumab 40 mg or sarilumab 200 mg in the phase 3 RCT MONARCH and sarilumab 200 mg in open-label extensions (OLEs) were used. DP was defined as an excess tender 28-joint count (TJC28) over swollen 28-joint count (SJC28) of ≥7 (TJC28 - SJC28 ≥ 7). Treatment response and disease activity were determined for patients with and without DP.

RESULTS

Of 1531 sarilumab 200 mg patients from RCTs, 353 (23%) had baseline DP. On average, patients with DP had higher 28-joint DAS using CRP (DAS28-CRP) and pain scores than patients without DP, whereas CRP levels were similar. After 12 and 24 weeks, patients with baseline DP treated with sarilumab were more likely to be DP-free than those treated with placebo or adalimumab. In RCTs, more sarilumab-treated patients achieved low disease activity vs comparators, regardless of baseline DP status. In OLEs, patients were more likely to lose rather than gain DP status.

CONCLUSION

About one-quarter of patients with RA experienced DP, which responded well to sarilumab. These data support the concept that other mechanisms (potentially mediated via IL-6) in addition to inflammation may contribute to DP in RA.

TRIAL REGISTRATIONS

NCT01061736, NCT02332590, NCT01709578, NCT01146652.

Hemophilic Arthropathy of the Knee and Its Association with Reduced Muscle Strength and Activation and the Pressure Pain Threshold: A Case-Control Study

(1) Background: Hemophilia is characterized by recurrent hemarthrosis leading to degenerative arthropathy. The aim was to evaluate the differences in muscle strength and activity and the pressure pain threshold between patients with knee arthropathy and their healthy peers; (2) Methods: A case-control study in which 23 adult patients with knee arthropathy and 24 healthy peers matched in terms of characteristics were recruited. The study variables were quadriceps muscle strength, muscle activation and the pressure pain threshold; (3) Results: There were significant differences between the two groups in quadriceps strength on the dominant (CI95%: 64.69, 129.2) and non-dominant (CI95%: 29.95, 93.55) sides and in the pressure pain threshold on the dominant (CI95%: 3.30, 43.54) and non-dominant (CI95%: 3.09, 45.25) sides. There were differences in neuromuscular fatigue on the non-dominant side in the vastus medialis (CI95%: 8.72, 21.51), vastus lateralis (CI95%: 4.84, 21.66) and rectus femoris (CI95%: 6.48, 24.95) muscles; (4) Conclusions: Muscle strength and the pressure pain threshold are lower in patients with hemophilia. Quadriceps muscle activation in patients with hemophilic knee arthropathy does not in any way differ from activation in healthy subjects. However, muscle fatigue is greater in patients with knee arthropathy. Strength training in patients with hemophilia should focus on the activation of the vastus medialis and lateralis muscles.

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.

180-degree immersive VR motion visualization in the treatment of haemophilic ankle arthropathy

BACKGROUND

Patients with haemophilic arthropathy suffer chronic pain that affects and restricts their quality of life. Visualization of movement through immersive virtual reality is used for pain management.

AIM

To evaluate the efficacy of 180-degree immersive VR motion visualization therapy in patients with haemophilic ankle arthropathy.

METHODS

Prospective, multicentre pilot study. Fifteen adult patients with bilateral haemophilic ankle arthropathy were recruited (mean age: 42.73 ± 12.36 years). The intervention lasted 4 weeks, with daily home sessions of 180-degree immersive motion visualization. The patients were given virtual reality glasses to use with their smartphones. From the YouTube mobile app® they accessed the recorded video with access from the He-Mirror App®. The study variables were joint state (Haemophilia Joint Health Score), pressure pain threshold (pressure algometer), muscle strength (dynamometry) and range of motion (goniometry). Three evaluations were performed: at baseline (T0), after the intervention (T1) and at the end of a 16-week follow-up period (T2).

RESULTS

No patient developed ankle hemarthrosis during the experimental phase. In the repeated measures analysis we found statistically significant differences in joint state (F = 51.38; η² _p = .63), pressure pain threshold of the lateral malleolus (F = 12.34; η² _p = .29) and range of motion (F = 11.7; η² _p = .28).

CONCLUSIONS

Therapy using immersive motion visualization does not cause hemarthrosis. This intervention can improve joint condition, pressure pain threshold and range of motion in patients with ankle arthropathy. Changes greater than the MDC were reported in more than 40% of patients for the variables pressure pain threshold, anterior tibialis strength and range of motion, which were considered clinically relevant.

Approach to Knee Arthropathy through 180-Degree Immersive VR Movement Visualization in Adult Patients with Severe Hemophilia: A Pilot Study

(1) Background: Hemarthrosis is a typical clinical manifestation in patients with hemophilia. Its recurrence causes hemophilic arthropathy, characterized by chronic joint pain. Watching movement recorded from a first-person perspective and immersively can be effective in the management of chronic pain. The objective of this study was to evaluate the effectiveness of an immersive virtual reality intervention in improving the pain intensity, joint condition, muscle strength and range of motion in patients with hemophilic knee arthropathy. (2) Methods: Thirteen patients with hemophilic knee arthropathy were recruited. The patients wore virtual reality glasses and watched a flexion-extension movement of the knee on an immersive 180° video, recorded from a first-person perspective over a 28-day period. The primary variable was the pain intensity (visual analog scale). The secondary variables were the joint status (Hemophilia Joint Health Score), quadriceps and hamstring strength (dynamometry), and range of motion (goniometry). (3) Results: After the intervention period, statistically significant differences were observed in the intensity of the joint pain (Standard error [SE] = 19.31; 95% interval confidence [95%CI] = -1.05; -0.26), joint condition (SE = 18.68; 95%CI = -1.16; -0.52) and quadriceps strength (SE = 35.00; 95%CI = 2.53; 17.47). We found that 38.46% and 23.07% of the patients exhibited an improvement in their quadriceps muscle strength and joint condition above the minimum detectable change for both variables (8.21% and 1.79%, respectively). (4) Conclusions: One hundred and eighty degree immersive VR motion visualization can improve the intensity of joint pain in patients with hemophilic knee arthropathy. An intervention using immersive virtual reality can be an effective complementary approach to improve the joint condition and quadriceps strength in these patients.

Correlation of Fibromyalgia Survey Questionnaire and Quantitative Sensory Testing Among Patients With Active Rheumatoid Arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) commonly demonstrate disordered pain processing associated with high pain sensitization. Pain sensitization is often assessed using quantitative sensory testing (QST), which is burdensome to patients. The self-administered Fibromyalgia Survey Questionnaire (FSQ) has been proposed as a low-burden, surrogate measure of central pain sensitization. We examined the correlation between FSQ and QST in patients with active RA.

METHODS

Participants in the Central Pain in Rheumatoid Arthritis (CPIRA) cohort underwent FSQ and QST evaluation at enrollment. QST measures included pressure pain threshold (PPT) at the thumb, trapezius, wrist, and knee; temporal summation (TS) at the wrist and arm; and conditioned pain modulation (CPM). Partial Spearman correlation between FSQ and each QST measure was assessed, adjusted for demographic factors, study site, disease characteristics, and pain catastrophizing. Sensitivity analyses included (1) stratified analysis by sex and (2) evaluation of how each component of FSQ associates with the QST measures.

RESULTS

Among 285 participants with active RA, FSQ was weakly but statistically significantly correlated with PPT (r range = -0.31 to -0.21), and TS (r range = 0.13-0.15) at all sites in unadjusted analyses. After adjustment, statistically significant correlations persisted for TS at the wrist and PPT at all sites (except the thumb). Sensitivity analyses did not identify differences in association based on sex or with individual FSQ components.

CONCLUSION

FSQ and QST were correlated among participants with active RA, but the strength of association was weak. QST and FSQ are not interchangeable measures of pain sensitization.

Acute effects of exercise on pain symptoms, clinical inflammatory markers and inflammatory cytokines in people with rheumatoid arthritis: a systematic literature review

Background

Exercise is advocated in the treatment of rheumatoid arthritis (RA). However, uncertainty around the acute effects of exercise on pain and inflammation may be stopping people with RA from exercising more regularly.

Objectives

To determine the acute effects of exercise on pain symptoms, clinical inflammatory markers, and inflammatory cytokines in RA.

Design

A systematic review of the literature.

Data sources and methods

Five databases were searched (PubMed, Cochrane Library, CINAHL, Scopus and SPORTDiscus); inclusion criteria were studies with acute exercise, a definite diagnosis of RA and disease characteristics assessed by clinical function (i.e., disease activity score, health assessment questionnaire and self-reported pain), clinical markers associated with inflammation (i.e., c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)), and inflammatory cytokines (i.e., interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α)).

Results

From a total of 1544 articles, initial screening and full text assessment left 11 studies meeting the inclusion criteria. A total of 274 people were included in the studies (RA = 186; control = 88). Acute bouts of aerobic, resistance, and combined aerobic and resistance exercise did not appear to exacerbate pain symptoms in people with RA.

Conclusion

Post-exercise responses for pain, clinical inflammatory markers and inflammatory cytokines were not different between people with or without RA. Exercise prescription was variable between studies, which limited between-study comparisons. Therefore, future investigations in people with RA are warranted, which combine different exercise modes and intensities to examine acute effects on pain symptoms and inflammatory markers.

Registration

The PROSPERO international prospective register of systematic reviews - CRD42018091155.

Back pain treatment: a new perspective

This article aims to provide new perspectives for the treatment of low back pain (LBP). A narrative literature review highlights the treatment strategies currently anchored in the guidelines as well as the extensive attempts to identify subgroups within the non-specific low back pain (NSLBP) classification. A variety of multimodal approaches exist for both diagnostic assessments and therapy approaches. Nonetheless, there are often gaps in the classification systems as well as in published treatment concepts with regard to the implementation of musculoskeletal functional disorders. Indeed, a growing body of evidence shows that more holistic and flexible approaches are needed to individually diagnose and target the complexity of LBP. As an example, both a diagnostic and a (independently developed) therapeutic LBP concept will be presented and discussed. Ultimately, guidelines and subgroup classification systems can only reflect the complexity of LBP, if they capture its entire multidimensional and biopsychosocial character in both the diagnostic and therapeutic processes. Furthermore, the expansion of the pain definition to include the nociplastic pain mechanism, as an important driver of LBP, has the potential to provide important impulses for further necessary research. In conclusion, the implementation of a functional musculoskeletal approach along with the emerging nociceptive pain concept in individually targeted holistic approaches seems to be the successful way to deal with the complexity of LBP.

Symptomatic but not Asymptomatic COVID-19 Impairs Conditioned Pain Modulation in Young Adults

Pain is a common symptom reported in COVID-19 patients. Impaired endogenous pain-modulatory mechanisms such as conditioned pain modulation (CPM), and exercise-induced hypoalgesia (EIH) have been found in chronic pain conditions but is often overlooked in acute conditions that evoke painful symptoms, such as COVID-19. The purpose was to compare pressure-pain sensitivity, CPM, and EIH function among individuals who previously had COVID-19, both symptomatically and asymptomatically, and a healthy control group. Pressure pain thresholds of 59 participants were assessed in the forearm and leg using a pressure algometer before and after 1) submersion of their dominant foot in cold water (2°C) for 1min; and 2) isometric knee extension performed to task-failure at 25% of their maximal contraction. The CPM response was attenuated in individuals who were infected with symptomatic COVID-19 (N = 26) compared to asymptomatic COVID-19 (N = 13) in arm (-1.0% ± 20.3 vs 33.3% ± 26.2; P < .001) and leg (12.8% ± 22.0 vs 33.8% ± 28.2; P = .014) and compared to controls (N = 20) in arm only (-1.0% ± 26.2 vs 23.4% ± 28.2; P = .004). The EIH response was not different between groups. CPM was impaired in individuals who had symptomatic COVID-19, which may have long-term implications on pain modulation.

Perspective

This study reveals that CPM was impaired in individuals who had symptomatic COVID-19 during the first wave of COVID-19, pre vaccine. These findings present a preliminary motive to study the long-term implications of COVID-19 and its effects on pain modulation.

LongHest project: A prospective, observational study of extended half-life treatment in the musculoskeletal health of patients with severe haemophilia A

Background

Prophylactic treatment is the gold standard in the treatment of patients with haemophilia. Prophylaxis with extended half‐life (EHL) treatment has shown long‐term safety and efficacy in patients with haemophilia.

Aim

To evaluate the efficacy of prophylaxis with EHL treatment in the frequency of haemarthrosis and musculoskeletal health in adult patients with severe haemophilia A.

Methods

Prospective cohort study. Forty‐six patients with severe haemophilia A were recruited. The frequency of haemarthrosis (self‐reports), joint condition (Haemophilia Joint Health Score), pain intensity (visual analogue scale), range of motion (goniometry), and strength (dynamometry) and muscle activation (surface electromyography) were evaluated. Three assessments were carried out: at baseline (T0), at 6 months (T1) and at 12 months following treatment (T2).

Results

There were significant changes in the within‐subject effect in the frequency of haemarthrosis in elbow (F(1.05;96.20) = 3.95; P < .001) and knee (F(1.73;157.99) = 9.96; P < .001). Significant within‐subject effect in elbow pain intensity (F(2;182) = 63.51; P < .001) was found. The mean values of the frequency haemarthrosis in elbow (from .66±1.01 to .04±.20) and knees (from .55±.68 to .33±.53) decrease after the period study. The intensity of elbow pain and (from 3.08±1.69 to 2.67±1.73), decrease after the 12‐month follow‐up period.

Conclusions

Prophylaxis with extended half‐life treatment reduces the frequency of haemarthrosis in elbow and knee in adult patients with haemophilia. EHL treatment reduces the intensity of elbow pain in patients with haemophilic arthropathy.

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.

Distinct aberrations in cerebral pain processing differentiating patients with fibromyalgia from patients with rheumatoid arthritis

ABSTRACT

The current study used functional magnetic resonance imaging to directly compare disease-relevant cerebral pain processing in well-characterized patient cohorts of fibromyalgia (FM, nociplastic pain) and rheumatoid arthritis (RA, nociceptive pain). Secondary aims were to identify pain-related cerebral alterations related to the severity of clinical symptoms such as pain intensity, depression, and anxiety. Twenty-six patients with FM (without RA-comorbidity) and 31 patients with RA (without FM-comorbidity) underwent functional magnetic resonance imaging while stimulated with subjectively calibrated painful pressures corresponding to a pain sensation of 50 mm on a 100-mm visual analogue scale. Stimulation sites were at the most inflamed proximal interphalangeal joint in the left hand in patients with RA and the left thumbnail in patients with FM, 2 sites that have previously been shown to yield the same brain activation in healthy controls. The current results revealed disease-distinct differences during pain modulation in RA and FM. Specifically, in response to painful stimulation, patients with FM compared to patients with RA exhibited increased brain activation in bilateral inferior parietal lobe (IPL), left inferior frontal gyrus (IFG)/ventrolateral prefrontal cortex (vlPFC) encapsulating left dorsolateral prefrontal cortex, and right IFG/vlPFC. However, patients with RA compared to patients with FM exhibited increased functional connectivity (during painful stimulation) between right and left IPL and sensorimotor network and between left IPL and frontoparietal network. Within the FM group only, anxiety scores positively correlated with pain-related brain activation in left dorsolateral prefrontal cortex and right IFG/vlPFC, which further highlights the complex interaction between affective (ie, anxiety scores) and sensory (ie, cerebral pain processing) dimensions in this patient group.

Vulvodynia-It Is Time to Accept a New Understanding from a Neurobiological Perspective

Vulvodynia is one the most common causes of pain during sexual intercourse in premenopausal women. The burden of vulvodynia in a woman's life can be devastating due to its consequences in the couple's sexuality and intimacy, in activities of daily living, and psychological well-being. In recent decades, there has been considerable progress in the understanding of vulvar pain. The most significant change has been the differentiation of vulvar pain secondary to pathology or disease from vulvodynia. However, although it is currently proposed that vulvodynia should be considered as a primary chronic pain condition and, therefore, without an obvious identifiable cause, it is still believed that different inflammatory, genetic, hormonal, muscular factors, etc. may be involved in its development. Advances in pain neuroscience and the central sensitization paradigm have led to a new approach to vulvodynia from a neurobiological perspective. It is proposed that vulvodynia should be understood as complex pain without relevant nociception. Different clinical identifiers of vulvodynia are presented from a neurobiological and psychosocial perspective. In this case, strategies to modulate altered central pain processing is necessary, changing the patient's erroneous cognitions about their pain, and also reducing fear avoidance-behaviors and the disability of the patient.

Musculoskeletal Changes in Hemophilia Patients Subsequent to COVID-19 Lockdown

(1) Background. The lockdown period due to the COVID−19 pandemic has drastically decreased levels of physical activity in the population. Hemophilia is characterized by hemarthrosis that leads to chronic, progressive and degenerative joint deterioration. (2) Methods. This observational study recruited 27 patients with hemophilia and arthropathy. Knee, ankle and elbow joints were assessed. The frequency of clinical hemarthrosis, pain intensity, pressure pain threshold, and joint ROM were evaluated. (3) Results. Following lockdown, a significant deterioration of joint condition, perceived joint pain and range of motion was noted in all joints. There were no changes in the frequency of knee hemarthrosis, while the frequency of ankle hemarthrosis significantly reduced. However, the frequency of elbow hemarthrosis increased. Depending on the degree of hemophilia severity, there were changes in pressure pain threshold in the elbow and in pain intensity and range of motion of the ankle joint. According to the type of treatment, i.e., prophylaxis vs. on-demand treatment, there were differences in the joint condition in elbows and the plantar flexion movement of the ankle. There were no differences in the knee joint based on the severity of the disease, the type of treatment or the development of inhibitors (4). Conclusions. Because of the COVID−19 lockdown, the musculoskeletal status of patients with hemophilia deteriorated. Joint condition, perceived pain, and range of motion were significantly affected. The frequency of clinical hemarthrosis did not increase during this period. A more active therapeutic model could prevent rapid deterioration in patients with hemophilic arthropathy during prolonged sedentary periods.

Contribution of P2X4 receptor in pain associated with rheumatoid arthritis: a review

Pain is the most common symptom reported by patients with rheumatoid arthritis (RA) even after the resolution of chronic joint inflammation. It is believed that RA-associated pain is not solely due to inflammation, but could also be attributed to aberrant modifications to the central nervous system. The P2X4 receptor (P2X4R) is an ATP-activated purinergic receptor that plays a significant role in the transmission of information in the nervous system and pain. The involvement of P2X4R during the pathogenesis of chronic inflammatory pain and neuropathic pain is well-established. The attenuation of this receptor alleviates disease pathogenesis and related symptoms, including hyperalgesia and allodynia. Although some studies have revealed the contribution of P2X4R in promoting joint inflammation in RA, how it implicates pain associated with RA at peripheral and central nervous systems is still lacking. In this review, the possible contributions of P2X4R in the nervous system and how it implicates pain transmission and responses were examined.

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.

Differences in Psychosocial Factors and Experimental Pain Sensitivity between Hispanics and non-Hispanic Whites from the U.S.-Mexico Border

PURPOSE

Research suggests that ethnicity is a predictor of pain-related outcomes; however, studies comparing the differences in experimental pain sensitivity between Hispanics and non-Hispanic Whites (NHW) are scarce. This study investigated these differences between Hispanics and NHW from the U.S- Mexico border.

METHODS

Fifty-eight healthy subjects completed the survey packet, which included a demographic and a psychosocial factors questionnaire. Participants underwent quantitative sensory testing which included heat pain threshold, heat pain tolerance, Suprathreshold Heat Pain Response (SHPR), and Conditioned Pain Modulation (CPM). SHPR was induced by repeated thermal stimuli in both thenar eminences. CPM was assessed using SHPR as the experimental stimulus, and cold pressor task as the conditioning stimulus.

RESULTS

Analyses showed significant differences in experimental pain measures believed to be representative of facilitatory pain processing including SHPR, and heat pain threshold, where Hispanics reported significantly higher pain ratings than NHW. Hispanics also reported higher levels of ethnic identity and acculturation. However, these factors were not significantly associated with experimental pain sensitivity.

CONCLUSION

The experimental pain sensitivity and psychosocial factors included in this study differed by ethnic group, where Hispanics reported significantly higher pain ratings, when compared to NHW. However, ethnic identity and acculturation were not associated with these pain-related outcomes. Overall, enhanced understanding by clinicians of pain sensitivity and disparities in the pain experience between ethnic groups allows for increased cultural sensitivity and can be used to optimize pain treatment on an individual-by-individual basis.

[Pain in rheumatic diseases : What can biologics and JAK inhibitors offer?]

Persistent pain despite adequate inflammation control poses a big challenge in many rheumatic diseases for patients as well as physicians. The focus of drug development over the past years was on anti-inflammatory therapies. Enormous progress has been made and several treatment options have been added. It has been observed that pain triggered by inflammation can be effectively treated by inflammation control; however, the chronic pain component remains a problem, is little studied and specific treatment options are missing. Pain is influenced by inflammatory mediators, such as cytokines, which act on peripheral nociceptors and lead to peripheral sensitization. If inflammation continues, this can potentially lead to central sensitization and chronification of pain via immigration of immune cells and/or local activation of e.g. microglia. This leads to increasing autonomization and uncoupling of pain from the actual inflammatory process. The present review deals with the question if bDMARD or tsDMARD also show benefits concerning pain processes in addition to the profound inhibitory effects on inflammation. There are preclinical data that show an influence on sensitization following the use of cytokine inhibitors. On the other hand, so far clinical data show that bDMARDs as well as tsDMARDs consistently rapidly and reliably reduce nociceptive inflammatory pain across disease entities. An effect especially on the process of central sensitization and therefore on chronification of pain cannot be finally evaluated based on the currently available data.

Associations between Patient Global Assessment scores and pain, physical function, and fatigue in rheumatoid arthritis: a post hoc analysis of data from phase 3 trials of tofacitinib

Background

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). We examined the degree to which Patient Global Assessment of Disease Activity (PtGA) was driven by patient-reported assessments of pain (Pain), physical function, and fatigue in patients receiving tofacitinib 5 mg twice daily or placebo, each with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs).

Methods

This post hoc analysis used data pooled from three randomized controlled trials in csDMARD-inadequate responder (csDMARD-IR) patients (ORAL Scan: NCT00847613; ORAL Standard: NCT00853385; ORAL Sync: NCT00856544). Using subgroup analysis from 2 × 2 tables, associations between PtGA and Pain, Health Assessment Questionnaire-Disability Index (HAQ-DI), and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) at month 3 were evaluated using Pearson’s Phi correlation coefficients. To support the main analysis, associations between select patient-reported outcomes (PROs) were also evaluated in csDMARD-naïve (ORAL Start; NCT01039688) and biologic (b)DMARD-IR (ORAL Step; NCT00960440) patients.

Results

Across csDMARD-IR treatment groups, low disease activity (defined as PtGA ≤ 20 mm), and moderate (≥ 30%) and substantial (≥ 50%) improvements from baseline in PtGA were associated with mild Pain (Visual Analog Scale score ≤ 20 mm), and moderate (≥ 30%) and substantial (≥ 50%) improvements from baseline in Pain; lack of Pain improvement was associated with little/no improvement in PtGA. In contrast, large proportions of csDMARD-IR patients who reported PtGA improvements did not report HAQ-DI or FACIT-F scores ≥ normative values (≤ 0.25 and ≥ 43.5, respectively) or changes in HAQ-DI or FACIT-F scores ≥ minimum clinically important difference (≥ 0.22 and ≥ 4.0, respectively). Generally, PtGA and Pain outcomes were moderately-to-strongly correlated at month 3 in csDMARD-IR patients, with weaker correlations evident between PtGA and HAQ-DI/FACIT-F outcomes. Similar findings were generally evident in csDMARD-naïve and bDMARD-IR patients.

Conclusions

This analysis supports the role of Pain as a key driver of PtGA in RA; physical function and fatigue play lesser roles in patients’ perceptions of disease activity. These findings corroborate the importance of improved PROs and attainment of low symptom states for optimizing patient care.

Trial registration

Clinicaltrials.gov: NCT00847613 (registered: February 19, 2009); NCT00853385 (registered: March 2, 2009); NCT00856544 (registered: March 5, 2009); NCT01039688 (registered: December 25, 2009); NCT00960440 (registered: August 17, 2009)

Self-Myofascial Release Intervention and Mobile App in Patients With Hemophilic Ankle Arthropathy: Protocol for a Randomized Controlled Trial

Background

Hemophilic ankle arthropathy is manifested by degenerative functional alterations and chronic pain. Myofascial release techniques are used to treat soft tissue adhesions, relieve pain, and reduce tissue sensitivity.

Objective

This study aims to evaluate the safety and efficacy of a protocol using self-myofascial release with a foam roller to be applied in patients with hemophilic ankle arthropathy.

Methods

Patients with ankle arthropathy (N=70) will be recruited, enrolled, and assigned to one of two groups—experimental or control—in a 1:1 allocation ratio. Patients will be recruited from 5 centers in different regions of Spain. Patient data will be collected at baseline, posttreatment, and follow-up. The primary outcome will be frequency of ankle joint bleeding (self-reported). The secondary outcomes will be ankle range of motion (measured with a digital goniometer); joint pain (measured with a visual analog scale and an algometer); joint status (measured using the Hemophilia Joint Health Score); muscle strength (measured with a dynamometer); functionality of lower limbs (measured using the 6-minute walking test); activity (self-reported); and muscle flexibility (measured using the fingertip-to-floor test). The treatment program includes 11 exercises that must be administered bilaterally. A mobile app will be developed where each patient will be able to observe the exercises to be carried out. Each session will last 15 minutes with 5 physiotherapy sessions per week for a period of 3 months. It is expected that patients with hemophilia who receive the foam roller intervention will show improvement in mobility, pain, and status of the ankle joint; muscle strength; and function in the lower extremities.

Results

The study has been approved by the institutional review board of the University of Murcia. Patient recruitment will begin in September 2020, and the intervention period will last until June 2021. Data collection will take place between September 2020 and October 2021.

Conclusions

This protocol describes a randomized clinical trial to examine the safety and efficacy of a self-myofascial release intervention using a foam roller in patients with hemophilic ankle arthropathy.

Trial Registration

ClinicalTrials.gov NCT03914287; http://clinicaltrials.gov/ct2/show/NCT03914287.

International Registered Report Identifier (IRRID)

PRR1-10.2196/15612

A Review on Chronic Pain in Rheumatoid Arthritis: A Focus on Activation of NR2B Subunit of N-Methyl-D-Aspartate Receptors

Chronic pain is a debilitating condition that occurs after tissue damage, which substantially affects the patient's emotional state and physical activity. The chronic pain in rheumatoid arthritis (RA) is the result of various autoimmune-induced inflammatory reactions in the joints. Both types of peripheral and central pain processing can lead to sensitisation. Non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying anti-rheumatic drugs (DMARDs) can result in potent anti-inflammatory effect. However, these drugs are not able to suppress the pain from RA for a prolonged period. For years, researchers have examined the role of the N-methyl-D-aspartic acid receptor 2B (NR2B) subunit of N-methyl-D-aspartate receptors (NMDAR) in chronic and neuropathic pain models. This NMDAR subtype can be found in at the peripheral and central nervous system and it represents an effective therapy for RA pain management. This review focuses on the NR2B subunit of NMDAR and the different pathways leading to its activation. Furthermore, specific attention is given to the possible involvement of NR2B subunit in the peripheral and central pathogenesis of RA.

Exploring the transcriptome of resident spinal microglia after collagen antibody-induced arthritis

Supplemental Digital Content is Available in the Text.

Glial inhibitors only reverse mechanical hypersensitivity in male mice subjected to arthritis. No obvious arthritis-related transcriptional difference was identified between male and female spinal microglia.

Recent studies have suggested a sexually dimorphic role of spinal glial cells in the maintenance of mechanical hypersensitivity in rodent models of chronic pain. We have used the collagen antibody–induced arthritis (CAIA) mouse model to examine differences between males and females in the context of spinal regulation of arthritis-induced pain. We have focused on the late phase of this model when joint inflammation has resolved, but mechanical hypersensitivity persists. Although the intensity of substance P, calcitonin gene–related peptide, and galanin immunoreactivity in the spinal cord was not different from controls, the intensity of microglia (Iba-1) and astrocyte (glial fibrillary acidic protein) markers was elevated in both males and females. Intrathecal administration of the glial inhibitors minocycline and pentoxifylline reversed mechanical thresholds in male, but not in female mice. We isolated resident microglia from the lumbar dorsal horns and observed a significantly lower number of microglial cells in females by flow cytometry analysis. However, although genome-wide RNA sequencing results pointed to several transcriptional differences between male and female microglia, no convincing differences were identified between control and CAIA groups. Taken together, these findings suggest that there are subtle sex differences in microglial expression profiles independent of arthritis. Our experiments failed to identify the underlying mRNA correlates of microglial actions in the late phase of the CAIA model. It is likely that transcriptional changes are either subtle and highly localised and therefore difficult to identify with bulk isolation techniques or that other factors, such as changes in protein expression or epigenetic modifications, are at play.

Disease activity in rheumatoid arthritis is inversely related to cerebral TSPO binding assessed by [11C]PBR28 positron emission tomography

Reumatoid Arthritis (RA) is an autoimmune disorder characterized by peripheral joint inflammation. Recently, an engagement of the brain immune system has been proposed. The aim with the current investigation was to study the glial cell activation marker translocator protein (TSPO) in a well characterized cohort of RA patients and to relate it to disease activity, peripheral markers of inflammation and autonomic activity. Fifteen RA patients and fifteen healthy controls matched for age, sex and TSPO genotype (rs6971) were included in the study. TSPO was measured using Positron emission tomography (PET) and the radioligand [¹¹C]PBR28. The outcome measure was total distribution volume (V_T) estimated using Logan graphical analysis, with grey matter (GM) as the primary region of interest. Additional regions of interest analyses as well as voxel-wise analyses were also performed. Clinical evaluation of disease activity, symptom assessments, serum analyses of cytokines and heart rate variability (HRV) analysis of 24 h ambulatory ECG were performed in all subjects. There were no statistically significant group differences in TSPO binding, either when using the primary outcome V_T or when normalizing V_T to the lateral occipital cortex (p > 0.05). RA patients had numerically lower V_T values than healthy controls (Cohen's D for GM = -0.21). In the RA group, there was a strong negative correlation between [¹¹C]PBR28 V_T in GM and disease activity (DAS28)(r = -0.745, p = 0.002, corrected for rs6971 genotype). Higher serum levels of IFNγ and TNF-α were found in RA patients compared to controls (p < 0.05) and several measures of autonomic activity showed significant differences between RA and controls (p < 0.05). However, no associations between markers of systemic inflammation or autonomic activity and cerebral TSPO binding were found. In conclusion, no statistically significant group differences in TSPO binding as measured with [¹¹C]PBR28 PET were detected. Within the RA group, lower cerebral TSPO binding was associated with higher disease activity, suggesting that cerebral TSPO expression may be related to disease modifying mechanisms in RA. In light of the earlier confirmed neuro-immune features of RA, these results warrant further investigations regarding neuro-immune joint-to-CNS signalling to open up for potentially new treatment strategies.

Exploiting endogenous opioids: Lessons learned from endomorphin 2 in the female rat

Effective management of chronic pain is demanded by ethical as well as medical considerations. Although opioid analgesics remain among the most effective pharmacotherapies for ameliorating many types of pain, their use is clouded by concerns regarding their addictive properties, underscored by the current epidemic of prescription opioid abuse and attendant deaths. Medicinal harnessing of endogenous opioid antinociception could provide a strategy for continuing to take advantage of the powerful antinociceptive properties of opioids while avoiding their abuse potential. Based on our studies of endogenous mechanism that suppress and facilitate spinal endomorphin 2 antinociception over the rat reproductive cycle, we identified multiple signaling molecules that could serve as targets for activating endogenous opioid analgesia for chronic pain management in women. Our findings emphasize the need for a precision medicine approach that includes stage of menstrual cycle as an important determinant of drug targets for (activating/harnessing) endogenous opioid antinociceptive systems/ capabilities. Utilization of drugs that harness endogenous opioid antinociception in accordance with varying physiological states represents a novel approach for effective pain management.

Long-term, health-enhancing physical activity is associated with reduction of pain but not pain sensitivity or improved exercise-induced hypoalgesia in persons with rheumatoid arthritis

Background

We aimed to evaluate the 1-year and 2-year outcome of a health-enhancing physical activity (HEPA) support program on global pain, pressure pain sensitivity, and exercise-induced segmental and plurisegmental hypoalgesia (EIH) in persons with rheumatoid arthritis (RA).

Methods

Thirty participants (27 women and 3 men) were recruited from a larger intervention cohort that engaged in strength training and moderate-intensity aerobic activity. Assessments were performed before the HEPA intervention and at 1-year and 2-year follow-ups. Global pain was assessed on a visual analogue scale (0–100). Pressure pain thresholds (PPTs) and suprathreshold pressure pain at rest corresponding to 4/10 (medium pain) (SP4) and 7/10 (strong pain) (SP7) on Borg CR 10 scale were assessed by algometry. In a subsample (n = 21), segmental and plurisegmental EIH were assessed during standardized submaximal static contraction (30% of the individual maximum), by algometry, alternately at the contracting right M. quadriceps and the resting left M. deltoideus.

Results

Global pain decreased from before the intervention to 2-year follow-up (median 11 to median 6, P = 0.040). PPTs and SP4 pressure pain at rest did not change from before the intervention to 2-year follow-up, while SP7 decreased from mean 647 kPa to mean 560 kPa (P = 0.006). Segmental EIH during static muscle contraction increased from the assessment before the intervention (from mean 1.02 to mean 1.42, P = 0.001), as did plurisegmental EIH (from mean 0.87 to mean 1.41, P <0.001). There were no statistically significant changes in segmental or plurisegmental EIH from before the intervention to 2-year follow-up.

Conclusion

Participation in a long-term HEPA support program was associated with reduced global pain, whereas pressure pain sensitivity at rest was not reduced and EIH did not change. Thus, our results do not favor the hypothesis that long-term HEPA reduces pain by improving descending pain inhibition in persons with RA.

Trial registration

ISRCTN25539102, ISRCTN registry, date assigned March 4, 2011. The trial was retrospectively registered.

MicroRNA‑143‑3p contributes to the regulation of pain responses in collagen‑induced arthritis

Patients with rheumatoid arthritis (RA) suffer from pain, which is associated with inflammation, peripheral and central pain processing, and joint structure damage. The aim of the present study was to investigate a key microRNA (miR) and its target genes that are involved in the pain responses of RA, and to clarify the mechanism of pain regulation. Collagen‑induced arthritis (CIA) was induced in DBA/1 and C57BL/6 mice. The paw swelling, mechanical withdrawal threshold (MWT), thermal withdrawal latency (TWL), and expression levels of tumor necrosis factor (TNF)‑α and prostaglandin (PG)E2 in the sera were investigated. Decreased MWT and TWL, and increased TNF‑α and PGE2, in the CIA model group were observed in DBA/1 and C57BL/6 mice. DBA/1 mice exhibited greater hyperalgesia and higher levels of inflammatory mediators. miR‑143‑3p expression in the blood and the dorsal root ganglion (DRG) were detected, and low miR‑143‑3p expression was demonstrated in the blood and DRG tissue of CIA mice. The target genes of miR‑143 were predicted and analyzed. A total of 1,305 genes were predicted and 55 pain‑associated genes were obtained. Prostaglandin‑endoperoxide synthase 2 (Ptgs2), MAS related GPR family member E (Mrgpre), prostaglandin D2 receptor and Tnf were selected as target genes of miR‑143. DRG cells were cultured and transfected with miR‑143‑3p inhibitor or mimic. The expression of Mrgpre, Ptgs2 and Tnf was significantly inhibited following miR‑143‑3p mimic transfection, while the expression of Mrgpre, Ptgs2 and Tnf was increased following inhibitor transfection. Additionally, the expression of pain‑associated genes in the DRG of mice was investigated and the expression of Ptgs2, Mrgpre and Tnf in the DRG of CIA mice was also significantly upregulated. These results revealed that CIA mice exhibited marked hyperalgesia and high levels of inflammatory pain mediators. Low expression of miR‑143‑3p negatively regulated the pain‑associated target genes, including Mrgpre, Ptgs2 and Tnf, thereby affecting chronic inflammatory pain and neuropathic pain in RA.

Pain Modulation: From Conditioned Pain Modulation to Placebo and Nocebo Effects in Experimental and Clinical Pain

Accumulating evidence reveal important applications of endogenous pain modulation assessment in healthy controls and in patients in clinical settings, as dysregulations in the balance of pain modulatory circuits may facilitate pain and promote chronification of pain. This article reviews data on pain modulation, focusing on the mechanisms and translational aspects of pain modulation from conditioned pain modulation (CPM) to placebo and nocebo effects in experimental and clinical pain. The specific roles of expectations, learning, neural and neurophysiological mechanisms of the central nervous system are briefly reviewed herein. The interaction between CPM and placebo systems in pain inhibitory pathways is highly relevant in the clinic and in randomized controlled trials yet remains to be clarified. Examples of clinical implications of CPM and its relationship to placebo and nocebo effects are provided. A greater understanding of the role of pain modulation in various pain states can help characterize the manifestation and development of chronic pain and assist in predicting the response to pain-relieving treatments. Placebo and nocebo effects, intrinsic to every treatment, can be used to develop personalized therapeutic approaches that improve clinical outcomes while limiting unwanted effects.

The subjective components of the Disease Activity Score 28-joints (DAS28) in rheumatoid arthritis patients and coexisting fibromyalgia

To determine the contribution of fibromyalgia (FM) to the subjective components of the Disease Activity Score 28-joints (DAS28) in patients with rheumatoid arthritis (RA), and to analyse the discriminatory performance of the derived DAS28 patient-reported components (DAS28-P) to identify patients with fibromyalgic RA. Consecutive RA patients underwent clinical and clinimetric assessment. The DAS28-P index was derived from the components of the DAS28 scores by rearranging the DAS28-ESR formula. Patients were distinguished by the presence of FM. Student parametric t tests or Mann-Whitney non-parametric U tests were used to determine any between-group differences. Receiver operating characteristic (ROC) curve analysis was used to test the ability of the DAS28-P index to distinguish patients with RA and those with fibromyalgic RA. The study involved 292 RA patients (80.5% females, mean age 63 years) with a mean disease duration of 11.6 ± 8.5 years. Forty-three patients (14.7%) had concomitant FM, and significantly higher tender joint count (p < 0.001), pain numerical rating scale, global health status (p = 0.007), and DAS28 scores (p = 0.006) than those without FM. The DAS28-P values were also significantly higher in the patients with FM (0.68 ± 0.09 vs 0.58 ± 0.06; p < 0.001). The discriminatory power of the DAS28-P was very good (area under the ROC of 0.858, optimal cut-off value of 0.631). The presence of FM strongly influences the DAS28 results. The assessment of patient-reported components to the DAS28 through the DAS28-P can be a useful way to identify patients with fibromyalgic RA.

Impaired Pain Modulation in Fibromyalgia Patients in Response to Social Distress Manipulation

OBJECTIVES

Fibromyalgia (FM), a chronic pain condition, is associated with abnormalities in pain modulation. A growing body of evidence has shown that social distress modulates pain sensitivity. The current study aimed to assess the effects of social distress manipulation on pain in FM patients compared with positive (rheumatoid arthritis, RA) and negative (pain-free) controls.

MATERIALS AND METHODS

FM, RA patients and pain-free controls (PFC) were recruited. Demographic, medical, and psychological data were collected. Each participant was exposed to 3 study conditions in a random order: the inclusion (positive social effects) and exclusion (negative social effects) conditions of Cyberball, a game that manipulates social distress, and a control condition. Pain sensitivity in response to nociceptive electrical and thermal (cold) stimuli was assessed before and during each study condition.

RESULTS

In response to electrical stimuli, pain decreased in both the inclusion and exclusion conditions in PFC and RA groups, whereas inclusion conditions significantly increased pain in the FM group. Social manipulation (inclusion or exclusion) did not affect pain sensitivity as measured in response to thermal stimulation.

DISCUSSION

These results are in line with previous studies demonstrating altered pain inhibition in FM patients, and suggest that unlike PFC or other non-"stress-related" chronic pain conditions, being socially included may increase pain perception in FM patients. Possible underlying mechanisms and clinical relevance are discussed.

Pain sensitivity at rest and during muscle contraction in persons with rheumatoid arthritis: a substudy within the Physical Activity in Rheumatoid Arthritis 2010 study

Background

We aimed to explore pressure pain sensitivity and the function of segmental and plurisegmental exercise-induced hypoalgesia (EIH) in persons with rheumatoid arthritis (RA) compared with healthy control subjects (HC).

Methods

Forty-six participants with RA (43 female, 3 male) and 20 HC (16 female, 4 male) participated in the study. Pressure pain thresholds, suprathreshold pressure pain at rest, and segmental and plurisegmental EIH during standardised submaximal contractions were assessed by algometry. Assessments of EIH were made by performing algometry alternately at the contracting (30% of the individual maximum) right m. quadriceps and the resting left m. deltoideus.

Results

Participants with RA had higher sensitivity to pressure pain (RA, 318 kPa; HC, 487 kPa; p < 0.001), suprathreshold pressure pain 4/10 (RA, 433 kPa; HC, 638 kPa; p = 0.001) and suprathreshold pressure pain 7/10 (RA, 620 kPa; HC, 851 kPa; p = 0.002) than HC. Segmental EIH (RA, 0.99 vs 1.27; p < 0.001; HC, 0.89 vs 1.10; p = 0.016) and plurisegmental EIH (RA, 0.95 vs 1.36; p < 0.001; HC, 0.87 vs 1.31; p < 0.001) increased significantly during static muscle contraction in both groups alike (p > 0.05).

Conclusions

Our results indicate a generally increased pain sensitivity but normal function of EIH among persons with RA and offer one possible explanation for pain reduction observed in this group of patients following clinical exercise programmes.

Trial registration

ISRCTN registry, ISRCTN25539102. Retrospectively registered on 4 March 2011.

Lower pain and higher muscular strength in immigrant women with vitamin D deficiency following vitamin D treatment

BACKGROUND

Vitamin D deficiency is common among immigrants in the Nordic region. It may lead to osteomalacia with severe musculoskeletal pain. There are reports that vitamin D deficiency without osteomalacia may lead to pain but little is known of the effect of treatment.

OBJECTIVE

To investigate whether a moderate dose of cholecalciferol and calcium improves strength and pain in a group of vitamin D deficient women.

DESIGN

Twentyfive immigrant women with vitamin D deficiency diagnosed during pregnancy were treated postpartum with a daily dose of 1,600 IU cholecalciferol and 1,000 mg of calcium. They were examined at the start of treatment and again after 3 months of treatement and the results were statistically compared.

SETTING

Southern parts of Stockholm.

MAIN OUTCOME MEASURES

Serum 25-hydroyvitamin D (25(OH)D), serum-parathyroid hormone (PTH), pain measured by a visual analogue scale (VAS), musculoskeletal strength by performance on a chair stand test (seconds), and bone tenderness by pressure algometer (kilo-Pascal).

RESULTS

Following the treatment, the 21 women attending had lowered cm in VAS, improved musculoskeletal strength, - and 25(OH)D levels were normalized.

CONCLUSIONS

A moderate dose of vitamin D normalized l vitamin D levels, improved muscular strength and reduced pain in this group of vitamin D deficient immigrant women.

Remaining Pain in Early Rheumatoid Arthritis Patients Treated With Methotrexate

Objective

To investigate the frequency of remaining pain in early rheumatoid arthritis (RA) after 3 months of treatment with methotrexate as the only disease modifying antirheumatic drug, with a special focus on patients with a good clinical response.

Methods

The study base was cases reported to a population‐based early RA cohort who had followup data from the Swedish Rheumatology Quality Register (n = 1,241). The Disease Activity Score in 28 joints European League Against Rheumatism (EULAR) response criteria were used to evaluate clinical response to treatment as good, moderate, and no response. The primary end point was remaining pain at the 3‐months followup visit, defined as pain >20 mm on a 100‐mm visual analog scale (VAS).

Results

Remaining pain in spite of a EULAR good response at followup was associated with higher baseline disability, using the Health Assessment Questionnaire (adjusted odds ratio [OR] 2.2 [95% confidence interval (95% CI) 1.4–3.4] per unit increase), and less baseline inflammation, using the erythrocyte sedimentation rate (adjusted OR 0.81 [95% CI 0.70–0.93] per 10‐mm increase). Similar associations were detected for remaining pain at followup in spite of low inflammatory activity, defined as a C‐reactive protein level <10. Increase in VAS pain during the treatment period was observed in 19% of the whole cohort, with frequencies in the EULAR response groups of 9% (good response), 15% (moderate response), and 45% (no response).

Conclusion

These results are in line with the hypothesis that a subgroup of early RA patients exhibits pain that is not inflammatory mediated, where alternative treatment strategies to traditional antiinflammatory medications need to be considered.

A Framework for Understanding the Relationship between Descending Pain Modulation, Motor Corticospinal, and Neuroplasticity Regulation Systems in Chronic Myofascial Pain

Myofascial pain syndrome (MPS) is a leading cause of chronic musculoskeletal pain. However, its neurobiological mechanisms are not entirely elucidated. Given the complex interaction between the networks involved in pain process, our approach, to providing insights into the neural mechanisms of pain, was to investigate the relationship between neurophysiological, neurochemical and clinical outcomes such as corticospinal excitability. Recent evidence has demonstrated that three neural systems are affected in chronic pain: (i) motor corticospinal system; (ii) internal descending pain modulation system; and (iii) the system regulating neuroplasticity. In this cross-sectional study, we aimed to examine the relationship between these three central systems in patients with chronic MPS of whom do/do not respond to the Conditioned Pain Modulation Task (CPM-task). The CPM-task was to immerse her non-dominant hand in cold water (0-1°C) to produce a heterotopic nociceptive stimulus. Corticospinal excitability was the primary outcome; specifically, the motor evoked potential (MEP) and intracortical facilitation (ICF) as assessed by transcranial magnetic stimulation (TMS). Secondary outcomes were the cortical excitability parameters [current silent period (CSP) and short intracortical inhibition (SICI)], serum brain-derived neurotrophic factor (BDNF), heat pain threshold (HPT), and the disability related to pain (DRP). We included 33 women, (18-65 years old). The MANCOVA model using Bonferroni's Multiple Comparison Test revealed that non-responders (n = 10) compared to responders (n = 23) presented increased intracortical facilitation (ICF; mean ± SD) 1.43 (0.3) vs. 1.11 (0.12), greater motor-evoked potential amplitude (μV) 1.93 (0.54) vs. 1.40 (0.27), as well a higher serum BDNF (pg/Ml) 32.56 (9.95) vs. 25.59 (10.24), (P < 0.05 for all). Also, non-responders presented a higher level of DRP and decreased HPT (P < 0.05 for all). These findings suggest that the loss of net descending pain inhibition was associated with an increase in ICF, serum BDNF levels, and DRP. We propose a framework to explain the relationship and potential directionality of these factors. In this framework we hypothesize that increased central sensitization leads to a loss of descending pain inhibition that triggers compensatory mechanisms as shown by increased motor cortical excitability.

The count of tender rather than swollen joints correlates with aortic stiffness in patients with rheumatoid arthritis

BACKGROUND

Patients with rheumatoid arthritis (RA) are at a higher cardiovascular (CV) risk in comparison to the general population. CV risk associates closely with aortic stiffness. Aim of this exploration was therefore to evaluate aortic stiffness in patients with RA and to examine its association with various RA associated parameters as well as with traditional CV risk factors.

METHODS

Measurements of carotid-femoral pulse wave velocity (cfPWV) were analyzed retrospectively in 38 RA patients and 25 controls. We investigated the statistical difference between cfPWV values in the two groups. Furthermore, we analyzed the associations of cfPWV with laboratory and clinical RA parameters including Disease Activity Score 28 and its components, rheumatoid factor, cyclic citrullinated peptide antibodies, antinuclear antibodies and RA duration. Finally, we explored the relationship of cfPWV with traditional CV risk factors in the RA group.

RESULTS

cfPWV was not significantly higher in RA patients in comparison to controls in an adjusted statistical model for confounding factors [-0.587 95 % CI (-1.38 to 0.201), p = 0.144]. Among RA patients there was a statistically significant correlation of cfPWV with age (rho = 0.544, p = 0.001) and the count of tender joints [0.051 95 % CI (0.008-0.207), p = 0.034]. Finally, C-reactive protein associated only marginally with cfPWV [0.105 95 % CI (-0.410 to 0.003), p = 0.053].

CONCLUSIONS

In RA patients the number of tender, rather than swollen joints correlates with stiffness of the aorta, as measured through cfPWV. Therefore, RA associated joint pain might play a role in the development of aortic stiffness and thus increase CV risk.

Intrinsic Brain Connectivity in Chronic Pain: A Resting-State fMRI Study in Patients with Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) is commonly accompanied by pain that is discordant with the degree of peripheral pathology. Very little is known about the cerebral processes involved in pain processing in RA. Here we investigated resting-state brain connectivity associated with prolonged pain in RA.

Methods: 24 RA subjects and 19 matched controls were compared with regard to both behavioral measures of pain perception and resting-resting state fMRI data acquired subsequently to fMRI sessions involving pain stimuli. The resting-state fMRI brain connectivity was investigated using 159 seed regions located in cardinal pain processing brain regions. Additional principal component based multivariate pattern analysis of the whole brain connectivity pattern was carried out in a data driven analysis to localize group differences in functional connectivity.

Results: When RA patients were compared to controls, we observed significantly lower pain resilience for pressure on the affected finger joints (i.e., P50-joint) and an overall heightened level of perceived global pain in RA patients. Relative to controls, RA patients displayed increased brain connectivity predominately for the supplementary motor areas, mid-cingulate cortex, and the primary sensorimotor cortex. Additionally, we observed an increase in brain connectivity between the insula and prefrontal cortex as well as between anterior cingulate cortex and occipital areas for RA patients. None of the group differences in brain connectivity were significantly correlated with behavioral parameters.

Conclusion: Our study provides experimental evidence of increased connectivity between frontal midline regions that are implicated in affective pain processing and bilateral sensorimotor regions in RA patients.