Biology and therapy of fibromyalgia. Evidence-based biomarkers for fibromyalgia syndrome

Conditioned pain modulation (CPM) paradigm type affects its sensitivity as a biomarker of fibromyalgia

Fibromyalgia (FM) is a widespread chronic pain syndrome, possibly associated with the presence of central dysfunction in descending pain inhibition pathways. Conditioned Pain Modulation (CPM) has been proposed as a biomarker of FM. Nonetheless, the wide variety of methods used to measure CPM has hampered robust conclusions being reached. To clarify the validity of CPM as a biomarker of FM, we tested two CPM paradigms (parallel and sequential) in a sample of 23 female patients and 23 healthy women by applying test (mechanical) stimuli and conditioning (pressure cuff) stimuli. We evaluated whether CPM indices could correctly classify patients and controls, and we also determined the correlations between the indices and clinical variables such as symptomatology, disease impact, depression, quality of life, pain intensity, pain interference, fatigue and numbness. In addition, we compared the clinical status of CPM responders (efficient pain inhibitory mechanism) and non-responders. We observed that only parallel CPM testing correctly classified about 70% of patients with FM. In addition, more than 80% of healthy participants were found to be responders, while the rate was about 50% in the FM patients. The sequential CPM test was not as sensitive, with a decrease of up to 40% in the response rate for both groups. On the other hand, we did not observe any correlation between CPM measures and clinical symptoms. In summary, our findings demonstrate the influence of the CPM paradigm used and confirm that CPM may be a useful marker to complement FM diagnosis. However, the findings also cast doubts on the sensitivity of CPM as a marker of pain severity in FM.

TMS in combination with a pain directed intervention for the treatment of fibromyalgia - A randomized, double-blind, sham-controlled trial

BACKGROUND

Fibromyalgia Syndrome (FMS) is a highly prevalent condition, that causes chronic pain and severe reduction in quality of life and productivity, as well as social isolation. Despite the significant morbidity and economic burden of FMS, current treatments are scarce.

OBJECTIVE

To investigate whether stimulation of ACC -mPFC activity by dTMS enhances a pain-directed psychotherapeutic intervention.

METHODS

19 FMS patients were randomised to receive either 20 sessions of dTMS or sham stimulation, each followed by a pain-directed psychotherapeutic intervention. With the H7 HAC coil or sham stimulation, we targeted the ACC -mPFC; specific brain areas that play a central role in pain processing. Clinical response to treatment was assessed with the McGill Pain Questionnaire Short Form (SF-MPQ), the Visual Analogue Fibromyalgia Impact Questionnaire, the Brief Pain Inventory questionnaire, and the Hamilton Depression Rating Scale.

RESULTS

DTMS treatment was safe and well tolerated by FMS patients. A significant decrease in the combined sensory and affective pain dimensions was specifically demonstrated in the dTMS cohort, as measured by the SF-MPQ (Significant group × time interaction [F(2, 32) = 3.51, p < .05,ηp2 = 0.18]; No significant changes were found in depressive symptoms in both the dTMS and sham groups.

CONCLUSION

Our results suggest that a course of dTMS combined with a pain-directed psychotherapeutic intervention can alleviate pain symptoms in FMS patients. Beyond clinical possibilities, future studies are needed to substantiate the innovative hypothesis that it is not dTMS alone, but rather dTMS-induced plasticity of pain-related networks, that enables the efficacy of pain-directed psychotherapeutic interventions.

Multi-Dimensional Validation of the Integration of Syntactic and Semantic Distance Measures for Clustering Fibromyalgia Patients in the Rheumatic Monitor Big Data Study

This study primarily aimed at developing a novel multi-dimensional methodology to discover and validate the optimal number of clusters. The secondary objective was to deploy it for the task of clustering fibromyalgia patients. We present a comprehensive methodology that includes the use of several different clustering algorithms, quality assessment using several syntactic distance measures (the Silhouette Index (SI), Calinski-Harabasz index (CHI), and Davies-Bouldin index (DBI)), stability assessment using the adjusted Rand index (ARI), and the validation of the internal semantic consistency of each clustering option via the performance of multiple clustering iterations after the repeated bagging of the data to select multiple partial data sets. Then, we perform a statistical analysis of the (clinical) semantics of the most stable clustering options using the full data set. Finally, the results are validated through a supervised machine learning (ML) model that classifies the patients back into the discovered clusters and is interpreted by calculating the Shapley additive explanations (SHAP) values of the model. Thus, we refer to our methodology as the clustering, distance measures and iterative statistical and semantic validation (CDI-SSV) methodology. We applied our method to the analysis of a comprehensive data set acquired from 1370 fibromyalgia patients. The results demonstrate that the K-means was highly robust in the syntactic and the internal consistent semantics analysis phases and was therefore followed by a semantic assessment to determine the optimal number of clusters (k), which suggested k = 3 as a more clinically meaningful solution, representing three distinct severity levels. the random forest model validated the results by classification into the discovered clusters with high accuracy (AUC: 0.994; accuracy: 0.946). SHAP analysis emphasized the clinical relevance of "functional problems" in distinguishing the most severe condition. In conclusion, the CDI-SSV methodology offers significant potential for improving the classification of complex patients. Our findings suggest a classification system for different profiles of fibromyalgia patients, which has the potential to improve clinical care, by providing clinical markers for the evidence-based personalized diagnosis, management, and prognosis of fibromyalgia patients.

A Comprehensive Review of the Genetic and Epigenetic Contributions to the Development of Fibromyalgia

This narrative review summarizes the current knowledge of the genetic and epigenetic contributions to the development of fibromyalgia (FM). Although there is no single gene that results in the development of FM, this study reveals that certain polymorphisms in genes involved in the catecholaminergic pathway, the serotonergic pathway, pain processing, oxidative stress, and inflammation may influence susceptibility to FM and the severity of its symptoms. Furthermore, epigenetic changes at the DNA level may lead to the development of FM. Likewise, microRNAs may impact the expression of certain proteins that lead to the worsening of FM-associated symptoms.

Pharmacological Interaction of Quercetin Derivatives of Tilia americana and Clinical Drugs in Experimental Fibromyalgia

Fibromyalgia (FM) is a pain syndrome characterized by chronic widespread pain and CNS comorbidities. Tilia americana var. mexicana is a medicinal species used to treat anxiety, insomnia, and acute or chronic pain. However, its spectrum of analgesic efficacy for dysfunctional pain is unknown. To investigate a possible therapeutic alternative for FM-type pain, an aqueous Tilia extract (TE) and its flavonoid fraction (FF) containing rutin and isoquercitrin were evaluated alone and/or combined with clinical drugs (tramadol—TRA and pramipexol—PRA) using the reserpine-induced FM model in rats. Chromatographic analysis allowed the characterization of flavonoids, while a histological analysis confirmed their presence in the brain. TE (10–100 mg/kg, i.p.) and FF (10–300 mg/kg, i.p.) produced significant and dose-dependent antihyperalgesic and antiallodynic effects equivalent to TRA (3–10 mg/kg, i.p.) or PRA (0.01–1 mg/kg, s.c.). Nevertheless, the combination of FF + TRA or FF + PRA resulted in an antagonistic interaction by possible competitive action on the serotonin transporter or µ-opioid and D₂ receptors, respectively, according to the in silico analysis. Flavonoids were identified in cerebral regions because of their self-epifluorescence. In conclusion, Tilia possesses potential properties to relieve FM-type pain. However, the consumption of this plant or flavonoids such as quercetin derivatives in combination with analgesic drugs might reduce their individual benefits.

Potential role of blood biomarkers in patients with fibromyalgia: a systematic review with meta-analysis

ABSTRACT

Fibromyalgia (FM) is a complex chronic pain condition. Its symptoms are nonspecific, and to date, no objective test exists to confirm FM diagnosis. Potential objective measures include the circulating levels of blood biomarkers. This systematic review and meta-analysis aim to review studies assessing blood biomarkers' levels in patients with FM compared with healthy controls. We systematically searched the PubMed, MEDLINE, EMBASE, and PsycINFO databases. Fifty-four studies reporting the levels of biomarkers in blood in patients with FM were included. Data were extracted, and the methodological quality was assessed independently by 2 authors. The methodological quality of 9 studies (17%) was low. The results of most studies were not directly comparable given differences in methods and investigated target immune mediators. Thus, data from 40 studies only were meta-analyzed using a random-effects model. The meta-analysis showed that patients with FM had significantly lower levels of interleukin-1 β and higher levels of IL-6, IL-8, tumor necrosis factor-alpha, interferon gamma, C-reactive protein, and brain-derived neurotrophic factor compared with healthy controls. Nevertheless, this systematic literature review and meta-analysis could not support the notion that these blood biomarkers are specific biomarkers of FM. Our literature review, however, revealed that these same individual biomarkers may have the potential role of identifying underlying pathologies or other conditions that often coexist with FM. Future research is needed to evaluate the potential clinical value for these biomarkers while controlling for the various confounding variables.

The neurologic pain signature responds to nonsteroidal anti-inflammatory treatment vs placebo in knee osteoarthritis

Supplemental Digital Content is Available in the Text.

fMRI-based measures, validated for nociceptive pain, respond to acute osteoarthritis pain, are not sensitive to placebo, and are mild-to-moderately sensitive to naproxen.

Introduction:

Many drug trials for chronic pain fail because of high placebo response rates in primary endpoints. Neurophysiological measures can help identify pain-linked pathophysiology and treatment mechanisms. They can also help guide early stop/go decisions, particularly if they respond to verum treatment but not placebo. The neurologic pain signature (NPS), an fMRI-based measure that tracks evoked pain in 40 published samples and is insensitive to placebo in healthy adults, provides a potentially useful neurophysiological measure linked to nociceptive pain.

Objectives:

This study aims to validate the NPS in knee osteoarthritis (OA) patients and test the effects of naproxen on this signature.

Methods:

In 2 studies (50 patients, 64.6 years, 75% females), we (1) test the NPS and other control signatures related to negative emotion in knee OA pain patients; (2) test the effect of placebo treatments; and (3) test the effect of naproxen, a routinely prescribed nonsteroidal anti-inflammatory drug in OA.

Results:

The NPS was activated during knee pain in OA (d = 1.51, P < 0.001) and did not respond to placebo (d = 0.12, P = 0.23). A single dose of naproxen reduced NPS responses (vs placebo, NPS d = 0.34, P = 0.03 and pronociceptive NPS component d = 0.38, P = 0.02). Naproxen effects were specific for the NPS and did not appear in other control signatures.

Conclusion:

This study provides preliminary evidence that fMRI-based measures, validated for nociceptive pain, respond to acute OA pain, do not appear sensitive to placebo, and are mild-to-moderately sensitive to naproxen.

Systematic Review of the Use of Intravenous Ketamine for Fibromyalgia

Background: Fibromyalgia, a complex disorder that affects 1% to 5% of the population, presents as widespread chronic musculoskeletal pain without physical or laboratory signs of any specific pathologic process. The mechanism, while still being explored, suggests central sensitization and disordered pain regulation at the spinal cord and supraspinal levels, with a resulting imbalance between excitation and inhibition that may alter central nervous system nociceptive processing. Nociceptive hypersensitivity results from activity of the N-methyl-D-aspartate receptor (NMDAR)-mediated glutamatergic synaptic transmission in the spinal cord and brain. Because ketamine, an NMDAR antagonist, may reduce induction of synaptic plasticity and maintenance of chronic pain states, the study of its use in intravenous form to treat fibromyalgia has increased. Methods: We conducted a literature search with the objectives of examining the effect of intravenous ketamine administration on pain relief, identifying side effects, and highlighting the need for clinical studies to evaluate ketamine infusion treatment protocols for patients with fibromyalgia. We used the keywords "fibromyalgia," "chronic pain," "ketamine," "intravenous," and "infusion" and found 7 publications that included 118 patients with fibromyalgia who met inclusion criteria. Results: Clinical studies revealed a short-term reduction-only for a few hours after the infusions-in self-reported pain intensity with single, low-dose, intravenous ketamine infusions, likely attributable to nociception-dependent central sensitization in fibromyalgia via NMDAR blockade. Case studies suggest that increases in the total dose of ketamine and longer, more frequent infusions may be associated with more effective pain relief and longer-lasting analgesia. Another neurotransmitter release may be contributing to this outcome. Conclusion: This systematic review suggests a dose response, indicating potential efficacy of intravenous ketamine in the treatment of fibromyalgia.

The use of Pilates for pain control in patients with fibromyalgia

Abstract Introduction: Although the Pilates method is commonly used to treat fibromyalgia (FM) in clinical practice, research is scarce, and little is known about its real effectiveness in pain management. Objective: Systematically review the literature to determine whether Pilates affects pain control in FM patients. Methods: The PubMed, Science Direct, PEDro and Cochrane databases were searched to identify randomized controlled trials that investigated the effects of Pilates in individuals diagnosed with FM. The descriptors used were: “pilates based exercise” OR “pilates training” OR “pilates exercise” OR “pilates” AND “fibromyalgia.” Independent reviewers performed abstract/full-text screening, data extraction, and methodological quality assessments using the PEDro scale. Results: The search identified 646 potential articles, four of which were used in the analysis. The Pilates method had positive effects on pain control, physical function, quality of life and biopsychosocial factors such as stress and depression in individuals with FM in four studies. However, improvement in these parameters did not differ between intervention groups in three studies. Additionally, the control group showed no significant improvement for the same parameters in one study. The PEDro scale scores of the studies ranged from 6 to 8 points. Conclusion: Evidence suggests that Pilates influences pain control in individuals with FM, and is more effective than no intervention or minimal intervention in the treatment of FM.

Is Two-Point Discrimination Test a New Diagnostic Method for the Diagnosis of Fibromyalgia?

INTRODUCTION

Fibromyalgia is a syndrome of obscure pathogenesis without objective diagnostic criteria and is frequently associated with diagnostic delays due to symptomatic heterogeneity. This study aimed at assessing the response to two-point discrimination test in extremities, neutrophil/lymphocyte ratio (NLR), Numeric Rating Scale (NRS) score, and Widespread Pain Index (WPI) score in patients with fibromyalgia.

METHODS

The patient group consisted of 26 subjects diagnosed with fibromyalgia based on the 2016 revision to the American College of Rheumatology 2010 diagnostic criteria, while 25 healthy individuals comprised the control group. In both groups, basal amplitude and somatosensorial temporal discrimination (STD) measurements at the dorsum of the hands and feet were performed in addition to NLR measurements. Also, NRS and WPI were determined in fibromyalgia patients.

RESULTS

STD was significantly prolonged in all extremities among fibromyalgia patients as compared to controls. WPI and NRS were also increased, paralleling the STD measurements in all extremities (p<0.05). NLR was higher in the patient group than in controls, although the difference was insignificant.

CONCLUSION

STD values were high in fibromyalgia patients. So, STD appears to have a potential role as an auxiliary diagnostic tool in fibromyalgia. Still, further studies are needed to support this conclusion.

Conditioned pain modulation and pain sensitivity in functional somatic disorders: The DanFunD study

Background

Disrupted pain regulation has been proposed as a component in functional somatic disorders (FSD). The objective of this study was to examine a general population sample, encompassing three delimitations of FSD while assessing pain sensitivity and conditioning pain modulation (CPM).

Methods

Pressure pain thresholds (PPTs) at the tibialis and trapezius muscles were recorded at baseline. During cold pressor stimulation of the hand, the tibialis PPTs were re‐assessed and the difference from baseline measures defined the CPM effect. Participants (n = 2,198, 53% females) were randomly selected from the adult Danish population. FSD was established by self‐reported symptom questionnaires.

Results

With a few exceptions, only weak associations were seen between PPTs and CPM in cases with FSD (p > .1). A high PPT was associated with lower odds of having multi‐organ bodily distress syndrome (OR^{PPT trapezius}: 0.66, 95% CI: 0.49–0.88, p = .005), with the symptom profile characterized by all symptoms (OR^{PPT trapezius}: 0.72, 95% CI: 0.58–0.90, p = .003 and OR^{PPT tibialis}: 0.75, 95% CI: 0.62–0.91, p = .004), and with multiple chemical sensitivity (OR^{PPT trapezius}: 0.81, 95% CI: 0.67–0.97, p = .022). High CPM was associated with high odds of having irritable bowel (OR^{CPM relative}: 1.22, 95% CI: 1.04–1.43, p = .013 and OR^{CPM absolute} = 2.66, 95% CI: 1.07–6.45, p = .033).

Conclusion

However, only PPT measured over the trapezius muscle were still significant after correction for multiple testing for the symptom profile characterized by all symptoms. Findings from this study do not support altered pain regulation in questionnaire‐based FSD which is in contrast with the existing presumption. Further epidemiological studies in this field are needed.

Significance

Disrupted pain regulation as measured by abnormal pain thresholds has been hypothesized as a central mechanism in Functional Somatic Disorders (FSD). The hypothesis has been raised in clinical setting where patients presented subjective and objective features of hypersensitivity. The present population‐based study does not support this notion. This points to the importance of further studies into the underlying pathophysiology mechanisms of FSD.

Fibromyalgia and Depression in Women: An 1H-NMR Metabolomic Study

Fibromyalgia is a chronic and systemic syndrome characterized by muscle, bone, and joint pain. It is a gender-specific condition with a 9:1 incidence ratio between women and men. Fibromyalgia is frequently associated with psychic disorders affecting the cognitive and emotional spheres. In the reported work, we compared 31 female fibromyalgia patients to 31 female healthy controls. They were analyzed for biochemical clinical parameters, for autoimmune markers, and were subjected to 1H-NMR metabolomics analysis. To identify a correlation between the metabolomic profile and the psychic condition, a subset of 19 fibromyalgia patients was subjected to HAM-A and HAM-D Hamilton depression tests. Multivariate statistical analysis showed the dysmetabolism of several metabolites involved in energy balance that are associated with systemic inflammatory conditions. The severity of depression worsens dysmetabolic conditions; conversely, glycine and glutamate, known for their critical role as neuromodulators, appear to be potential biomarkers of fibromyalgia and are associated with different severity depression conditions.

Altered sub-processes of working memory in fibromyalgia patients: An ERP study using N-back task

OBJECTIVE

Cognitive dysfunction in fibromyalgia has become a key symptom considered by patients as more disabling than pain itself. Experimental evidence from neuropsychological and neuroimaging studies indicates that such cognitive impairments are especially robust when patients need to set in motion working memory processes, suggesting the existence of an altered functioning underlying the cerebral cortices of the frontoparietal memory network. However, the temporal dynamics of working memory sub-processes have not yet been explored in fibromyalgia.

SUBJECTS

Thirty-six right-handed women participated in the experiment: comprising eighteen patients with fibromyalgia and eighteen healthy controls.

METHODS

Event-related potentials (ERPs) and behavioural responses were recorded while participants were engaged in a 2-back working memory task. Principal Component Analyses (PCA) were used to define and quantify the ERP components associated with working memory processes.

RESULTS

Fibromyalgia patients exhibited worse performance than the control group, as revealed by their number of errors in the working memory task. Moreover, both scalp parieto-occipital P2 and parieto-occipital P3 amplitudes were lower for patients than for healthy control participants. Regression analyses revealed that lower P3 amplitudes were observed in those patients with fibromyalgia reporting higher pain ratings.

CONCLUSIONS

Current results suggest that both encoding of information (as reflected by P2) and subsequently, context updating and the replacement (as seen in lower P3 amplitudes), as a part of working memory sub-processes, are impaired in fibromyalgia. Studying the temporal dynamics of working memory using ERP methodology is a helpful approach to detect specific cognitive impaired mechanisms in this chronic pain syndrome. These new data could be used to develop more specific treatments adapted for each patient.

Phoneutria nigriventer Tx3-3 peptide toxin reduces fibromyalgia symptoms in mice

Fibromyalgia is characterized by the amplification of central nervous system pain with concomitant fatigue, sleep, mood disorders, depression, and anxiety. It needs extensive pharmacological therapy. In the present study, Swiss mice were treated with reserpine (0.25 mg/kg, s.c.) over three consecutive days, in order to reproduce the pathogenic process of fibromyalgia. On day 4, the administrations of the Tx3-3 toxin produced significant antinociception in the mechanical allodynia (87.16% ±12.7%) and thermal hyperalgesia (49.46% ± 10.6%) tests when compared with the PBS group. The effects produced by the classical analgesics (duloxetine 30 mg/kg, pramipexole 1 mg/kg, and pregabalin 30 mg/kg, p.o., respectively) in both of the tests also demonstrated antinociception. The administrations were able to increase the levels of the biogenic amines (5-HTP and DE) in the brain. The treatments with pramipexole and pregabalin, but not duloxetine, decreased the immobility time in the FM-induced animals that were submitted to the forced swimming test; however, the Tx3-3 toxin (87.45% ± 4.3%) showed better results. Taken together, the data has provided novel evidence of the ability of the Tx3-3 toxin to reduce painful and depressive symptoms, indicating that it may have significant potential in the treatment of FM.

Translation, validation and cross-cultural adaptation of the Revised Fibromyalgia Impact Questionnaire (FIQR) in Nepali language

OBJECTIVE

To translate, cross-culturally adapt and test the psychometric properties of the Revised Fibromyalgia Impact Questionnaire (FIQR) in Nepali language (Nepali FIQR).

METHODS

The translation was performed following the methodological standards described by Beaton. Comprehensibility testing of the preliminary version was done in 40 fibromyalgia patients, and a pre-final version was prepared after making changes in the original version to maintain the equivalence with the target version. Psychometric testing was done in another group of 130 fibromyalgia patients to test for content validity and reliability. Construct validity was tested with visual analog score (VAS) for pain and Short Form (SF)-36.

RESULTS

Nepali FIQR was comprehensible to 92.5% patients. The internal consistency was also acceptable with Cronbach's alpha of 0.900, 0.714 and 0.863 for function, overall and symptoms domain, respectively. Construct validity was also acceptable with a moderate correlation between Nepali FIQR and VAS and SF-36. Test-retest reliability of the total Nepali FIQR and of each item were acceptable with intraclass correlation coefficient (ICC) of >0.7 in all items except for question 1 of function domain (ICC: 0.65).

CONCLUSIONS

Nepali FIQR is a comprehensible, reliable and valid tool for evaluation of the functional status of Nepalese patients with fibromyalgia and should be implemented in routine clinical care and research settings.

Attenuation of reserpine-induced fibromyalgia via ROS and serotonergic pathway modulation by fisetin, a plant flavonoid polyphenol

Fibromyalgia (FM) is a chronic complex musculoskeletal disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep disturbance, memory defects and mood changes. Fisetin, a plant flavonoid polyphenol, has been reported to possess potent antioxidant, antinociceptive and neuroprotective activities. The present study aimed to evaluate the efficacy of fisetin against reserpine-induced FM (RIF) in rats. RIF was induced in male Wistar rats (180–220 gm) using reserpine (1 mg/kg; subcutaneous; once daily for 3 consecutive days) and the rats were treated with fisetin (5, 10 and 25 mg/kg) for 21 days. Various behavioral, biochemical and molecular parameters were evaluated. Administration of reserpine induced allodynia, hyperalgesia and depression, which were significantly ameliorated (P<0.05) by fisetin (10 and 25 mg/kg), as reflected by an increase in paw and tail withdrawal latency, increased paw withdrawal threshold, and decreased immobility time. Reserpine led to decreased biogenic amine levels [5-hydroxytryptamine (5-HT), noradrenaline (NA) and dopamine (DA)] and increased the ratio to their metabolite 3,4-dihydroxyphenylacetic acid. 5-hydroxyindoleacetic acid in the spinal cord, thalamus and prefrontal cortex was significantly decreased (P<0.05) by fisetin. Immunohistological analysis of brain tissue revealed that fisetin significantly inhibited (P<0.05) reserpine-induced depletion of 5-HT. It also significantly inhibited (P<0.05) elevated oxido-nitrosative stress and reactive oxygen species (ROS) levels, as analyzed by flow cytometry in RIF rats. Fisetin exerts its antinociceptive and anti-depressive potential via modulation of decreased levels of biogenic amines (5-HT, NA and DA), elevated oxido-nitrosative stress and ROS to ameliorate allodynia, hyperalgesia, and depression in experimental RIF.

Electroacupuncture attenuates chronic fibromyalgia pain through the phosphorylated phosphoinositide 3-kinase signaling pathway in the mouse brain

Objectives

Fibromyalgia (FM) is a central nervous system disorder characterized by widespread mechanical hyperalgesia due to unknown mechanisms. Several inflammatory mediators, such as interleukin-1 (IL-1), IL-6, IL-8, and tumor necrosis factor, are increased in the serum of FM patients. Although medications including pregabalin, duloxetine, and milnacipran are used to treat FM, the results are unsatisfying. In the present study we assessed whether electroacupuncture (EA) can reduce chronic FM pain and then proposed an underlying mechanism for this effect.

Materials and Methods

Chronic FM pain was induced in mice by dual acid saline injection lasting up to 4 weeks.

Results

Chronic FM pain was treated by EA manipulation, but not in the sham operated group. Phosphorylated phosphatidylinositol 3-kinase (pPI3K), protein kinase B, mechanistic target of rapamycin, and nuclear factor kappa-light-chain-enhancer of activated B cells were unaltered in the mouse dorsal root ganglion (DRG) and spinal cord (SC) after inducing FM and administering EA treatment. The pPI3K-associated nociceptive signaling pathway was increased in the thalamus of FM mice, but reversed by EA. Similar results were observed in the mouse somatosensory cortex.

Conclusion

These data suggest that EA has a significant effect on a signaling pathway in brain areas of FM mice. These findings suggest the value of EA for clinical practice.

Neuroimmunology: What Role for Autoimmunity, Neuroinflammation, and Small Fiber Neuropathy in Fibromyalgia, Chronic Fatigue Syndrome, and Adverse Events after Human Papillomavirus Vaccination?

Fibromyalgia is a disorder characterized by chronic widespread pain and non-pain symptoms, such as fatigue, dysautonomia, and cognitive and sleep disturbances. Its pathogenesis and treatment continue to be the subject of debate. We highlight the role of three mechanisms-autoimmunity, neuroinflammation, and small fiber neuropathy-in the pathogenesis of the disease. These mechanisms are shown to be closely interlinked (also on a molecular level), and the review considers the implementation of this relationship in the search for therapeutic options. We also pay attention to chronic fatigue syndrome, which overlaps with fibromyalgia, and propose a concept of "autoimmune hypothalamopathy" for its pathogenesis. Finally, we analyze the molecular mechanisms underlying the neuroinflammatory background in the development of adverse events following HPV vaccination and suggesting neuroinflammation, which could exacerbate the development of symptoms following HPV vaccination (though this is hotly debated), as a model for fibromyalgia pathogenesis.

Flexibility exercise training for adults with fibromyalgia

BACKGROUND

Exercise training is commonly recommended for adults with fibromyalgia. We defined flexibility exercise training programs as those involving movements of a joint or a series of joints, through complete range of motion, thus targeting major muscle-tendon units. This review is one of a series of reviews updating the first review published in 2002.

OBJECTIVES

To evaluate the benefits and harms of flexibility exercise training in adults with fibromyalgia.

SEARCH METHODS

We searched the Cochrane Library, MEDLINE, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature), PEDro (Physiotherapy Evidence Database), Thesis and Dissertation Abstracts, AMED (Allied and Complementary Medicine Database), the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), and ClinicalTrials.gov up to December 2017, unrestricted by language, and we reviewed the reference lists of retrieved trials to identify potentially relevant trials.

SELECTION CRITERIA

We included randomized trials (RCTs) including adults diagnosed with fibromyalgia based on published criteria. Major outcomes were health-related quality of life (HRQoL), pain intensity, stiffness, fatigue, physical function, trial withdrawals, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected articles for inclusion, extracted data, performed 'Risk of bias' assessments, and assessed the certainty of the body of evidence for major outcomes using the GRADE approach. All discrepancies were rechecked, and consensus was achieved by discussion.

MAIN RESULTS

We included 12 RCTs (743 people). Among these RCTs, flexibility exercise training was compared to an untreated control group, land-based aerobic training, resistance training, or other interventions (i.e. Tai Chi, Pilates, aquatic biodanza, friction massage, medications). Studies were at risk of selection, performance, and detection bias (due to lack of adequate randomization and allocation concealment, lack of participant or personnel blinding, and lack of blinding for self-reported outcomes). With the exception of withdrawals and adverse events, major outcomes were self-reported and were expressed on a 0-to-100 scale (lower values are best, negative mean differences (MDs) indicate improvement). We prioritized the findings of flexibility exercise training compared to land-based aerobic training and present them fully here.Very low-certainty evidence showed that compared with land-based aerobic training, flexibility exercise training (five trials with 266 participants) provides no clinically important benefits with regard to HRQoL, pain intensity, fatigue, stiffness, and physical function. Low-certainty evidence showed no difference between these groups for withdrawals at completion of the intervention (8 to 20 weeks).Mean HRQoL assessed on the Fibromyalgia Impact Questionnaire (FIQ) Total scale (0 to 100, higher scores indicating worse HRQoL) was 46 mm and 42 mm in the flexibility and aerobic groups, respectively (2 studies, 193 participants); absolute change was 4% worse (6% better to 14% worse), and relative change was 7.5% worse (10.5% better to 25.5% worse) in the flexibility group. Mean pain was 57 mm and 52 mm in the flexibility and aerobic groups, respectively (5 studies, 266 participants); absolute change was 5% worse (1% better to 11% worse), and relative change was 6.7% worse (2% better to 15.4% worse). Mean fatigue was 67 mm and 71 mm in the aerobic and flexibility groups, respectively (2 studies, 75 participants); absolute change was 4% better (13% better to 5% worse), and relative change was 6% better (19.4% better to 7.4% worse). Mean physical function was 23 points and 17 points in the flexibility and aerobic groups, respectively (1 study, 60 participants); absolute change was 6% worse (4% better to 16% worse), and relative change was 14% worse (9.1% better to 37.1% worse). We found very low-certainty evidence of an effect for stiffness. Mean stiffness was 49 mm to 79 mm in the flexibility and aerobic groups, respectively (1 study, 15 participants); absolute change was 30% better (8% better to 51% better), and relative change was 39% better (10% better to 68% better). We found no evidence of an effect in all-cause withdrawal between the flexibility and aerobic groups (5 studies, 301 participants). Absolute change was 1% fewer withdrawals in the flexibility group (8% fewer to 21% more), and relative change in the flexibility group compared to the aerobic training intervention group was 3% fewer (39% fewer to 55% more). It is uncertain whether flexibility leads to long-term effects (36 weeks after a 12-week intervention), as the evidence was of low certainty and was derived from a single trial.Very low-certainty evidence indicates uncertainty in the risk of adverse events for flexibility exercise training. One adverse effect was described among the 132 participants allocated to flexibility training. One participant had tendinitis of the Achilles tendon (McCain 1988), but it is unclear if the tendinitis was a pre-existing condition.

AUTHORS' CONCLUSIONS

When compared with aerobic training, it is uncertain whether flexibility improves outcomes such as HRQoL, pain intensity, fatigue, stiffness, and physical function, as the certainty of the evidence is very low. Flexibility exercise training may lead to little or no difference for all-cause withdrawals. It is also uncertain whether flexibility exercise training has long-term effects due to the very low certainty of the evidence. We downgraded the evidence owing to the small number of trials and participants across trials, as well as due to issues related to unclear and high risk of bias (selection, performance, and detection biases). While flexibility exercise training appears to be well tolerated (similar withdrawal rates across groups), evidence on adverse events was scarce, therefore its safety is uncertain.

Does aerobic exercise associated with tryptophan supplementation attenuates hyperalgesia and inflammation in female rats with experimental fibromyalgia?

The objective of this study was to verify the effects of aerobic exercise associated with tryptophan (TRP) supplementation on hyperalgesia, as well as on cortisol, IL-6 and TNF concentrations in female rats with experimental fibromyalgia (FM). Female Wistar rats (initial body weight: ~ 350 g; age: 12 months) were randomly divided into 5 groups: CON (Control); F (Fibromyalgia induced); FE (Fibromyalgia induced plus exercise); FES (Fibromyalgia induced plus exercise and TRP supplementation) and FS (Fibromyalgia induced plus TRP supplementation). Fibromyalgia was induced with two injections (20 μL) of acidic saline (pH 4.0) into the right gastrocnemius muscle with a 3-day interval. Control animals received the same doses of neutral saline (pH 7.4). The exercised animals underwent progressive low-intensity aerobic exercise (LIAE) on a treadmill (10–12 m/min, 30–45 min/day, 5 days/week) for three weeks. During this period, the supplemented animals received a TRP supplemented diet (210 g/week), while the others received a control diet. Mechanical hyperalgesia was evaluated weekly and serum cortisol and muscle IL-6 and TNF concentrations were assessed after three weeks of interventions. Experimental FM caused bilateral hind paw hyperalgesia and augmented serum cortisol and muscle IL-6 concentrations. After 3 weeks of interventions, LIAE alone reduced hyperalgesia (151%) and reduced serum cortisol concentrations (72%). Tryptophan supplementation itself diminished hyperalgesia (57%) and reduced serum cortisol concentrations (67%). Adding TRP supplementation to LIAE did not further reduce hyperalgesia significantly (11%), which was followed by an important decrease in muscle IL-6 concentrations (68%), though reduction in serum cortisol pulled back to 45%. Muscle TNF concentrations were not affected. In conclusion, the association of TRP supplementation to LIAE does not potentiate significantly the reduction of bilateral mechanical hyperalgesia promoted by LIAE in female rats with experimental FM, however an important decrease in IL-6 is evident.

Amand RP, Neuhausen SL, Shively JE. SNPs in inflammatory genes CCL11, CCL4 and MEFV in a fibromyalgia family study

BACKGROUND

Fibromyalgia (FM) is a chronic pain syndrome with a high incidence in females that may involve activation of the immune system. We performed exome sequencing on chemokine genes in a region of chromosome 17 identified in a genome-wide family association study.

METHODS AND FINDINGS

Exome sequence analysis of 100 FM probands was performed at 17p13.3-q25 followed by functional analysis of SNPs found in the chemokine gene locus. Missense SNPs (413) in 17p13.3-q25 were observed in at least 10 probands. SNPs rs1129844 in CCL11 and rs1719152 in CCL4 were associated with elevated plasma chemokine levels in FM. In a transmission disequilibrium test (TDT), rs1129844 was unequally transmitted from parents to their affected children (p< 0.0074), while the CCL4 SNP was not. The amino acid change (Ala23Thr), resulting from rs1129844 in CCL11, predicted to alter processing of the signal peptide, led to reduced expression of CCL11. The variant protein from CCL4 rs1719152 exhibited protein aggregation and a potent down-regulation of its cognate receptor CCR5, a receptor associated with hypotensive effects. Treatment of skeletal muscle cells with CCL11 produced high levels of CCL4 suggesting CCL11 regulates CCL4 in muscle. The immune association of FM with SNPs in MEFV, a chromosome 16 gene associated with recurrent fevers, had a p< 0.008 TDT for a combined 220 trios.

CONCLUSIONS

SNPs with significant TDTs were found in 36% of the cohort for CCL11 and 12% for MEFV, along with a protein variant in CCL4 (41%) that affects CCR5 down-regulation, supporting an immune involvement for FM.

Role of Asic3, Nav1.7 and Nav1.8 in Electroacupuncture-Induced Analgesia in a Mouse Model of Fibromyalgia Pain

Background

The mechanisms underlying fibromyalgia (FM) pain are not understood. The US Food and Drug Administration has recommended three drugs for treating FM—namely, pregabalin, duloxetine and milnacipran; however, these medications are associated with severe side effects.

Objective

To create a mouse model of FM pain using dual injections of acidic saline to cause mechanical hyperalgesia and test whether ASIC3, Nav1.7 and Nav1.8 are involved in this process and whether electroacupuncture (EA) can reverse these phenomena.

Methods

The FM model was established by injecting acidic saline twice into 40 ICR mice. The mice were assigned to subgroups (n=8 each) treated with different EA frequencies (2, 15 and 50 Hz). ASIC3, Nav1.7 and Nav1.8 expression levels were measured by Western blotting and immunohistochemistry.

Results

Significant mechanical hyperalgesia was induced on day 8 in FM mice, which was reversed by 2, 15 and 50 Hz EA. ASIC3, Nav1.7 and Nav1.8 protein levels increased significantly in both the dorsal root ganglion and in the spinal cord of FM model mice. These changes were further attenuated by 2, 15 and 50 Hz EA.

Conclusion

Reduced nociceptive ASIC3, Nav1.7 and Nav1.8 proteins are involved in the preventive effects of EA against FM, and this series of molecules may represent targets for FM treatment.

Dysfunctional stress responses in chronic pain

Many dysfunctional and chronic pain conditions overlap. This review describes the different modes of chronic deregulation of the adaptive response to stress which may be a common factor for these conditions. Several types of dysfunction can be identified within the hypothalamo-pituitary-adrenal axis: basal hypercortisolism, hyper-reactivity, basal hypocortisolism and hypo-reactivity. Neuroactive steroid synthesis is another component of the adaptive response to stress. Dehydroepiandrosterone (DHEA) and its sulfated form DHEA-S, and progesterone and its derivatives are synthetized in cutaneous, nervous, and adipose cells. They are neuroactive factors that act locally. They may have a role in the localization of the symptoms and their levels can vary both in the central nervous system and in the periphery. Persistent changes in neuroactive steroid levels or precursors can induce localized neurodegeneration. The autonomic nervous system is another component of the stress response. Its dysfunction in chronic stress responses can be expressed by decreased basal parasympathethic activity, increased basal sympathetic activity or sympathetic hyporeactivity to a stressful stimulus. The immune and genetic systems also participate. The helper-T cells Th1 secrete pro-inflammatory cytokines such as IL-1-β, IL-2, IL-6, IL-8, IL-12, IFN-γ, and TNF-α, whereas Th2 secrete anti-inflammatory cytokines: IL-4, IL-10, IGF-10, IL-13. Chronic deregulation of the Th1/Th2 balance can occur in favor of anti- or pro-inflammatory direction, locally or systemically. Individual vulnerability to stress can be due to environmental factors but can also be genetically influenced. Genetic polymorphisms and epigenetics are the main keys to understanding the influence of genetics on the response of individuals to constraints.

Effects of electroacupuncture in a mouse model of fibromyalgia: role of N-methyl-D-aspartate receptors and related mechanisms

Objective

N-methyl-D-aspartate receptor (NMDAR) activation and downstream transduction pathways are crucial for pain signalling. Fibromyalgia (FM) is a common pain syndrome of unclear aetiology that is often drug-refractory but may benefit from treatment with electroacupuncture (EA). We examined the contributions of NMDAR signalling to FM pain and EA responses in a mouse model.

Methods

A model of FM was established by acid saline injection in 32 mice and subgroups (n=8 each) were treated with EA (2 Hz, 15 min daily for 4 days) or minimal acupuncture (MA). Expression of NMDAR subunits, calmodulin-dependent protein kinase II (CaMKII), cyclic AMP response element binding protein (pCREB) and their corresponding phospho-activated forms were measured by Western blotting and immunohistochemistry.

Results

Acid saline injection induced significant mechanical hyperalgesia (paw withdrawal threshold 2.18±0.27 g, p<0.05 vs controls), which was reversed by EA (4.23±0.33 g, p<0.05 vs FM group) but not by MA (2.37±0.14 g, p<0.05 vs EA group). Expression levels of phosphorylated N-methyl-D-aspartate receptor (pNR)1 and pNR2B were significantly increased in the dorsal root ganglion of FM model mice (132.21±14.4% and 116.69±3.22% of control values), whereas NR1 and NR2B levels were unchanged (97.31±3.79% and 97.07%±2.27%, respectively). Expression levels of pCaMKIIα and pCREB were also higher in the FM group, and these changes were reversed by EA but not by MA. Similar changes in expression were observed in spinal cord neurons.

Conclusions

Reduced NMDAR−CaMKIIα−pCREB signalling is implicated in the positive effects of EA in FM. NMDAR signalling components may represent promising therapeutic targets for FM treatment.

[Fibromyalgia syndrome: A disease of the small nerve fibers?]

Fibromyalgia syndrome (FMS) is characterized by chronic widespread pain and additional associated symptoms, such as fatigue, sleep disturbances and depressive moods. The pathophysiology of pain in FMS is unclear. In recent years, an involvement of the thinly myelinated A-delta and the unmyelinated C-nerve fibers has been reported in FMS patients. Independent research groups published consistent objective and multidimensional findings of damage to these small nerve fibers, such as disturbances of fiber function, electrical properties and morphological changes. All these alterations are not specific for FMS; however, they were described for the first time in subgroups of FMS patients. While the reasons for this small fiber pathology and its contribution to FMS pain are still unclear, a new research field has now been opened that will focus on uncovering the underlying pathophysiology. This review article summarizes these new findings and discusses the significance for the understanding of FMS.

Food intake assessment and quality of life in women with fibromyalgia

OBJECTIVE

To compare the food intake of women with and without fibromyalgia and verify if the food intake of patients with fibromyalgia interferes with the pain and quality of life.

METHODS

Study participants were women with fibromyalgia (FM) seen in Fibromyalgia Outpatient Clinic, Hospital das Clínicas/UFPR and a control group (CT) with healthy women. Data collection was conducted from March to October 2012. For the assessment of food intake we used the Food Registration and the analyzed items were total calories, carbohydrates, proteins, lipids, vitamins (A, C, B12, D and E) and minerals (folate, selenium, zinc, iron, calcium and magnesium). The software used was Avanutri Online(®). To evaluate the quality of life, the Fibromyalgia Impact Questionnaire (FIQ) and pain threshold were used.

RESULTS

43 patients with FM and 44 healthy women were evaluated. CT group showed a mean consumption of nutrients greater than FM group except for iron. However, only caloric intake, carbohydrates, proteins and lipids in grams and percentage of lipids, vitamin A, E, B12, folate, selenium and calcium were statistically significant. In FM group, there was a negative correlation between vitamin E and FIQ and a positive correlation between percentage of protein and pain threshold.

CONCLUSION

Women with FM showed a lower qualitative and quantitative intake in comparison with CT group. Only vitamin E correlated with quality of life and percentage of protein in the diet with sensation of pain.

Depressive-like symptoms in a reserpine-induced model of fibromyalgia in rats

Since the pathogenesis of fibromyalgia is unknown, treatment options are limited, ineffective and in fact based on symptom relief. A recently proposed rat model of fibromyalgia is based on central depletion of monamines caused by reserpine administration. This model showed widespread musculoskeletal pain and depressive-like symptoms, but the methodology used to measure such symptoms has been criticized. Evidence relates the high prevalence of pain and depression in fibromyalgia to common pathogenic pathways, most probably focused on the monoaminergic system. The present study aims at a validation of the reserpine model of fibromyalgia. For this purpose, rats undergoing this model have been tested for depressive-like symptoms with a Novelty-Suppressed Feeding Test adaptation. Animals administered with reserpine and subjected to forced food deprivation performed a smaller number of incursions to the center of the open field, evidenced by a decrease in the per-minute rate of the rats' approaching, smelling or touching the food. They also took more time to eat from the central food than control rats. These NSFT findings suggest the presence of depressive-like disorders in this animal model of fibromyalgia.

'I've Been Walking on Eggshells All My Life': Fibromyalgia Patients' Narratives About Experienced Violence and Abuse

According to earlier research, the prevalence of violence and abuse in the life history of patients with chronic widespread pain and fibromyalgia seems to be high in comparison with other pain patients and healthy controls. The purpose of the present study was to explore how experiences of violence and abuse are expressed and reflected on and how the causes and consequences of violence are interpreted by female patients with a long history of fibromyalgia. The data were drawn from narrative interviews of 11 women who had earlier participated in a fibromyalgia-specific rehabilitation course. The findings are presented through three main themes: loss of self-esteem, physical and mental bruises, and loss of womanhood. The onset of fibromyalgia was perceived as an inevitable result of physical or mental trauma. In conclusion, the narrated life stories indicated that violence is still hidden behind a wall of silence and non-interference in our society. The devastating mental and physical consequences of violence in different forms may be carried by the individual for years, even decades. Understanding any exposure to violence that a patient has endured may help healthcare professionals to understand the individual's health behaviour and any possible reluctance to undergo treatment and rehabilitation. Copyright © 2015 John Wiley & Sons, Ltd.

Salivary cortisol and cold pain sensitivity in female twins

BACKGROUND

There is a dearth of knowledge about the link between cortisol and pain sensitivity.

PURPOSE

We examined the association of salivary cortisol with indices of cold pain sensitivity in 198 female twins and explored the role of familial confounding.

METHODS

Three-day saliva samples were collected for cortisol levels and a cold pressor test was used to collect pain ratings and time to threshold and tolerance. Linear regression modeling with generalized estimating equations examined the overall and within-pair associations.

RESULTS

Lower diurnal variation of cortisol was associated with higher pain ratings at threshold (p = 0.02) and tolerance (p < 0.01). The relationship of diurnal variation with pain ratings at threshold and tolerance was minimally influenced by familial factors (i.e., genetics and common environment).

CONCLUSIONS

Understanding the genetic and non-genetic mechanisms underlying the link between HPA axis dysregulation and pain sensitivity may help to prevent chronic pain development and maintenance.

Animal models of fibromyalgia

Animal models of disease states are valuable tools for developing new treatments and investigating underlying mechanisms. They should mimic the symptoms and pathology of the disease and importantly be predictive of effective treatments. Fibromyalgia is characterized by chronic widespread pain with associated co-morbid symptoms that include fatigue, depression, anxiety and sleep dysfunction. In this review, we present different animal models that mimic the signs and symptoms of fibromyalgia. These models are induced by a wide variety of methods that include repeated muscle insults, depletion of biogenic amines, and stress. All potential models produce widespread and long-lasting hyperalgesia without overt peripheral tissue damage and thus mimic the clinical presentation of fibromyalgia. We describe the methods for induction of the model, pathophysiological mechanisms for each model, and treatment profiles.

Aquatic exercise training for fibromyalgia

BACKGROUND

Exercise training is commonly recommended for individuals with fibromyalgia. This review examined the effects of supervised group aquatic training programs (led by an instructor). We defined aquatic training as exercising in a pool while standing at waist, chest, or shoulder depth. This review is part of the update of the 'Exercise for treating fibromyalgia syndrome' review first published in 2002, and previously updated in 2007.

OBJECTIVES

The objective of this systematic review was to evaluate the benefits and harms of aquatic exercise training in adults with fibromyalgia.

SEARCH METHODS

We searched The Cochrane Library 2013, Issue 2 (Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Health Technology Assessment Database, NHS Economic Evaluation Database), MEDLINE, EMBASE, CINAHL, PEDro, Dissertation Abstracts, WHO international Clinical Trials Registry Platform, and AMED, as well as other sources (i.e., reference lists from key journals, identified articles, meta-analyses, and reviews of all types of treatment for fibromyalgia) from inception to October 2013. Using Cochrane methods, we screened citations, abstracts, and full-text articles. Subsequently, we identified aquatic exercise training studies.

SELECTION CRITERIA

Selection criteria were: a) full-text publication of a randomized controlled trial (RCT) in adults diagnosed with fibromyalgia based on published criteria, and b) between-group data for an aquatic intervention and a control or other intervention. We excluded studies if exercise in water was less than 50% of the full intervention.

DATA COLLECTION AND ANALYSIS

We independently assessed risk of bias and extracted data (24 outcomes), of which we designated seven as major outcomes: multidimensional function, self reported physical function, pain, stiffness, muscle strength, submaximal cardiorespiratory function, withdrawal rates and adverse effects. We resolved discordance through discussion. We evaluated interventions using mean differences (MD) or standardized mean differences (SMD) and 95% confidence intervals (95% CI). Where two or more studies provided data for an outcome, we carried out meta-analysis. In addition, we set and used a 15% threshold for calculation of clinically relevant differences.

MAIN RESULTS

We included 16 aquatic exercise training studies (N = 881; 866 women and 15 men). Nine studies compared aquatic exercise to control, five studies compared aquatic to land-based exercise, and two compared aquatic exercise to a different aquatic exercise program.We rated the risk of bias related to random sequence generation (selection bias), incomplete outcome data (attrition bias), selective reporting (reporting bias), blinding of outcome assessors (detection bias), and other bias as low. We rated blinding of participants and personnel (selection and performance bias) and allocation concealment (selection bias) as low risk and unclear. The assessment of the evidence showed limitations related to imprecision, high statistical heterogeneity, and wide confidence intervals. Aquatic versus controlWe found statistically significant improvements (P value < 0.05) in all of the major outcomes. Based on a 100-point scale, multidimensional function improved by six units (MD -5.97, 95% CI -9.06 to -2.88; number needed to treat (NNT) 5, 95% CI 3 to 9), self reported physical function by four units (MD -4.35, 95% CI -7.77 to -0.94; NNT 6, 95% CI 3 to 22), pain by seven units (MD -6.59, 95% CI -10.71 to -2.48; NNT 5, 95% CI 3 to 8), and stiffness by 18 units (MD -18.34, 95% CI -35.75 to -0.93; NNT 3, 95% CI 2 to 24) more in the aquatic than the control groups. The SMD for muscle strength as measured by knee extension and hand grip was 0.63 standard deviations higher compared to the control group (SMD 0.63, 95% CI 0.20 to 1.05; NNT 4, 95% CI 3 to 12) and cardiovascular submaximal function improved by 37 meters on six-minute walk test (95% CI 4.14 to 69.92). Only two major outcomes, stiffness and muscle strength, met the 15% threshold for clinical relevance (improved by 27% and 37% respectively). Withdrawals were similar in the aquatic and control groups and adverse effects were poorly reported, with no serious adverse effects reported. Aquatic versus land-basedThere were no statistically significant differences between interventions for multidimensional function, self reported physical function, pain or stiffness: 0.91 units (95% CI -4.01 to 5.83), -5.85 units (95% CI -12.33 to 0.63), -0.75 units (95% CI -10.72 to 9.23), and two units (95% CI -8.88 to 1.28) respectively (all based on a 100-point scale), or in submaximal cardiorespiratory function (three seconds on a 100-meter walk test, 95% CI -1.77 to 7.77). We found a statistically significant difference between interventions for strength, favoring land-based training (2.40 kilo pascals grip strength, 95% CI 4.52 to 0.28). None of the outcomes in the aquatic versus land comparison reached clinically relevant differences of 15%. Withdrawals were similar in the aquatic and land groups and adverse effects were poorly reported, with no serious adverse effects in either group. Aquatic versus aquatic (Ai Chi versus stretching in the water, exercise in pool water versus exercise in sea water)Among the major outcomes the only statistically significant difference between interventions was for stiffness, favoring Ai Chi (1.00 on a 100-point scale, 95% CI 0.31 to 1.69).

AUTHORS' CONCLUSIONS

Low to moderate quality evidence relative to control suggests that aquatic training is beneficial for improving wellness, symptoms, and fitness in adults with fibromyalgia. Very low to low quality evidence suggests that there are benefits of aquatic and land-based exercise, except in muscle strength (very low quality evidence favoring land). No serious adverse effects were reported.

Inflammation-induced hyperalgesia: effects of timing, dosage, and negative affect on somatic pain sensitivity in human experimental endotoxemia

BACKGROUND

Inflammation-induced pain amplification and hypersensitivity play a role in the pathophysiology of numerous clinical conditions. Experimental endotoxemia has recently been implemented as model to analyze immune-mediated processes in human pain. In this study, we aimed to analyze dose- and time-dependent effects of lipopolysaccharide (LPS) on clinically-relevant pain models for musculoskeletal and neuropathic pain as well as the interaction among LPS-induced changes in inflammatory markers, pain sensitivity and negative affect.

METHODS

In this randomized, double-blind, placebo-controlled study, healthy male subjects received an intravenous injection of either a moderate dose of LPS (0.8 ng/kg Escherichiacoli), low-dose LPS (0.4 ng/kg), or saline (placebo control group). Pressure pain thresholds (PPT), mechanical pain sensitivity (MPS), and cold pain sensitivity (CP) were assessed before and 1, 3, and 6h post injection to assess time-dependent LPS effects on pain sensitivity. Plasma cytokines (TNF-α, IL-6, IL-8, IL-10) and state anxiety were repeatedly measured before, and 1, 2, 3, 4, and 6h after injection of LPS or placebo.

RESULTS

LPS administration induced a systemic immune activation, reflected by significant increases in cytokine levels, body temperature, and negative mood with pronounced effects to the higher LPS dose. Significant decreases of PPTs were observed only 3h after injection of the moderate dose of LPS (0.8 ng/kg). MPS and CP were not affected by LPS-induced immune activation. Correlation analyses revealed that decreased PPTs were associated with peak IL-6 increases and negative mood.

CONCLUSIONS

Our results revealed widespread increases in musculoskeletal pain sensitivity in response to a moderate dose of LPS (0.8 ng/kg), which correlate both with changes in IL-6 and negative mood. These data extend and refine existing knowledge about immune mechanisms mediating hyperalgesia with implications for the pathophysiology of chronic pain and neuropsychiatric conditions.

Extraintestinal manifestations of Helicobacter pylori: A concise review

Helicobacter pylori (H. pylori) infection has been clearly linked to peptic ulcer disease and some gastrointestinal malignancies. Increasing evidence demonstrates possible associations to disease states in other organ systems, known as the extraintestinal manifestations of H. pylori. Different conditions associated with H. pylori infection include those from hematologic, cardiopulmonary, metabolic, neurologic, and dermatologic systems. The aim of this article is to provide a concise review of the evidence that supports or refutes the associations of H. pylori and its proposed extraintestinal manifestations. Based on data from the literature, PUD, mucosal associated lymphoid tumors lymphoma, and gastric adenocarcinoma has well-established links. Current evidence most supports extraintestinal manifestations with H. pylori in immune thrombocytopenic purpura, iron deficiency anemia, urticaria, Parkinson’s, migraines and rosacea; however, there is still plausible link with other diseases that requires further research.

Profiles in fibromyalgia: algometry, auditory evoked potentials and clinical characterization of different subtypes

The heterogeneity found in fibromyalgia (FM) patients has led to the investigation of disease subgroups, mainly based on clinical features. The aim of this study was to test the hypothesis that clinical FM subgroups are associated with different underlying pathophysiological mechanisms. Sixty-three FM patients were classified in type I or type II, according to the Fibromyalgia Impact Questionnaire (FIQ), and in mild/moderate versus severe FM, according to the severity of three cardinal symptoms considered in the American College of Rheumatology (ACR) 2010 criteria (unrefreshed sleep, cognitive problems and fatigue). To validate the subgroups obtained by these two classifications, we calculated the area under the receiver operating characteristic curves for various clinical variables and for two potential biomarkers of FM: Response to experimental pressure pain (algometry) and the amplitude/intensity slopes of the auditory evoked potentials (AEPs) obtained to stimuli of increasing intensity. The variables that best discriminated type I versus type II were those related to depression, while the indices of clinical or experimental pain (threshold or tolerance) did not significantly differ between them. The variables that best discriminated the mild/moderate versus severe subgroups were those related to the algometry. The AEPs did not allow discrimination among the generated subsets. The FIQ-based classification allows the identification of subgroups that differ in psychological distress, while the index based on the ACR 2010 criteria seems to be useful to characterize the severity of FM mainly based on hyperalgesia. The incorporation of potential biomarkers to generate or validate classification criteria is crucial to advance in the knowledge of FM and in the understanding of pathophysiological pathways.

Effects of guided imagery on biobehavioral factors in women with fibromyalgia

Women diagnosed with fibromyalgia (N = 72) participated in a 10-week randomized trial to examine the effectiveness of guided imagery on self-efficacy, perceived stress, and selected biobehavioral factors (FMS symptoms; immune biomarkers). Participants in both guided imagery and usual care control conditions completed measures and donated 3 cc of blood at baseline, 6- and 10-weeks. A mixed effects linear model to test for differences between groups for all behavioral and biologic variables demonstrated that after 10 weeks of daily intervention use, guided imagery participants reported statistically significant increases in self-efficacy and statistically significant decreases in stress, fatigue, pain, and depression. There were no statistically significant changes in biomarker levels, although total group C-reactive protein was elevated at baseline (4.7 mg/L), indicating an inflammatory process. Subsequent studies should be undertaken to more fully elucidate the biobehavioral aspects of nonpharmacological intervention effectiveness.

Resistance exercise training for fibromyalgia

BACKGROUND

Fibromyalgia is characterized by chronic widespread pain that leads to reduced physical function. Exercise training is commonly recommended as a treatment for management of symptoms. We examined the literature on resistance training for individuals with fibromyalgia. Resistance training is exercise performed against a progressive resistance with the intention of improving muscle strength, muscle endurance, muscle power, or a combination of these.

OBJECTIVES

To evaluate the benefits and harms of resistance exercise training in adults with fibromyalgia. We compared resistance training versus control and versus other types of exercise training.

SEARCH METHODS

We searched nine electronic databases (The Cochrane Library, MEDLINE, EMBASE, CINAHL, PEDro, Dissertation Abstracts, Current Controlled Trials, World Health Organization (WHO) International Clinical Trials Registry Platform, AMED) and other sources for published full-text articles. The date of the last search was 5 March 2013. Two review authors independently screened 1856 citations, 766 abstracts and 156 full-text articles. We included five studies that met our inclusion criteria.

SELECTION CRITERIA

Selection criteria included: a) randomized clinical trial, b) diagnosis of fibromyalgia based on published criteria, c) adult sample, d) full-text publication, and e) inclusion of between-group data comparing resistance training versus a control or other physical activity intervention.

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently assessed risk of bias and extracted intervention and outcome data. We resolved disagreements between the two review authors and questions regarding interpretation of study methods by discussion within the pairs or when necessary the issue was taken to the full team of 11 members. We extracted 21 outcomes of which seven were designated as major outcomes: multidimensional function, self reported physical function, pain, tenderness, muscle strength, attrition rates, and adverse effects. We evaluated benefits and harms of the interventions using standardized mean differences (SMD) or mean differences (MD) or risk ratios or Peto odds ratios and 95% confidence intervals (CI). Where two or more studies provided data for an outcome, we carried out a meta-analysis.

MAIN RESULTS

The literature search yielded 1865 citations with five studies meeting the selection criteria. One of the studies that had three arms contributed data for two comparisons. In the included studies, there were 219 women participants with fibromyalgia, 95 of whom were assigned to resistance training programs. Three randomized trials compared 16 to 21 weeks of moderate- to high-intensity resistance training versus a control group. Two studies compared eight weeks of progressive resistance training (intensity as tolerated) using free weights or body weight resistance exercise versus aerobic training (ie, progressive treadmill walking, indoor and outdoor walking), and one study compared 12 weeks of low-intensity resistance training using hand weights (1 to 3 lbs (0.45 to 1.36 kg)) and elastic tubing versus flexibility exercise (static stretches to major muscle groups).Statistically significant differences (MD; 95% CI) favoring the resistance training interventions over control group(s) were found in multidimensional function (Fibromyalgia Impact Questionnaire (FIQ) total decreased 16.75 units on a 100-point scale; 95% CI -23.31 to -10.19), self reported physical function (-6.29 units on a 100-point scale; 95% CI -10.45 to -2.13), pain (-3.3 cm on a 10-cm scale; 95% CI -6.35 to -0.26), tenderness (-1.84 out of 18 tender points; 95% CI -2.6 to -1.08), and muscle strength (27.32 kg force on bilateral concentric leg extension; 95% CI 18.28 to 36.36).Differences between the resistance training group(s) and the aerobic training groups were not statistically significant for multidimensional function (5.48 on a 100-point scale; 95% CI -0.92 to 11.88), self reported physical function (-1.48 units on a 100-point scale; 95% CI -6.69 to 3.74) or tenderness (SMD -0.13; 95% CI -0.55 to 0.30). There was a statistically significant reduction in pain (0.99 cm on a 10-cm scale; 95% CI 0.31 to 1.67) favoring the aerobic groups.Statistically significant differences were found between a resistance training group and a flexibility group favoring the resistance training group for multidimensional function (-6.49 FIQ units on a 100-point scale; 95% CI -12.57 to -0.41) and pain (-0.88 cm on a 10-cm scale; 95% CI -1.57 to -0.19), but not for tenderness (-0.46 out of 18 tender points; 95% CI -1.56 to 0.64) or strength (4.77 foot pounds torque on concentric knee extension; 95% CI -2.40 to 11.94). This evidence was classified low quality due to the low number of studies and risk of bias assessment. There were no statistically significant differences in attrition rates between the interventions. In general, adverse effects were poorly recorded, but no serious adverse effects were reported. Assessment of risk of bias was hampered by poor written descriptions (eg, allocation concealment, blinding of outcome assessors). The lack of a priori protocols and lack of care provider blinding were also identified as methodologic concerns.

AUTHORS' CONCLUSIONS

The evidence (rated as low quality) suggested that moderate- and moderate- to high-intensity resistance training improves multidimensional function, pain, tenderness, and muscle strength in women with fibromyalgia. The evidence (rated as low quality) also suggested that eight weeks of aerobic exercise was superior to moderate-intensity resistance training for improving pain in women with fibromyalgia. There was low-quality evidence that 12 weeks of low-intensity resistance training was superior to flexibility exercise training in women with fibromyalgia for improvements in pain and multidimensional function. There was low-quality evidence that women with fibromyalgia can safely perform moderate- to high-resistance training.

Milnacipran combined with pregabalin in fibromyalgia: a randomized, open-label study evaluating the safety and efficacy of adding milnacipran in patients with incomplete response to pregabalin

OBJECTIVE

To evaluate the safety, tolerability, and efficacy of adding milnacipran to pregabalin in patients with fibromyalgia who have experienced an incomplete response to pregabalin.

METHODS

In this randomized, multicenter, open-label study, patients received pregabalin 300 or 450 mg/day during a 4- to 12-week run-in period. Patients with weekly recall visual analog scale (VAS) pain score of at least 40 and up to 90, Patient Global Impression of Severity score of at least 4, and Patient Global Impression of Change (PGIC) score of at least 3 were classified as incomplete responders and randomized to continue pregabalin alone (n = 180) or receive milnacipran 100 mg/day added to pregabalin (n = 184). The primary efficacy parameter was responder status based on PGIC score of up to 2. The secondary efficacy parameter was change from randomization in weekly recall VAS pain score. Safety parameters included adverse events (AEs), vital signs, and clinical laboratory tests.

RESULTS

The percentage of PGIC responders was significantly higher with milnacipran added to pregabalin (46.4%) than with pregabalin alone (20.8%; p < 0.001). Mean improvement from randomization in weekly recall VAS pain scores was greater in patients receiving milnacipran added to pregabalin (-20.77) than in patients receiving pregabalin alone (-6.43; p < 0.001). During the run-in period, the most common treatment-emergent AEs with pregabalin were dizziness (22.8%), somnolence (17.3%), and fatigue (9.1%). During the randomized period, the most common treatment-emergent AEs with milnacipran added to pregabalin were nausea (12.5%), fatigue (10.3%), and constipation (9.8%).

CONCLUSIONS

In this exploratory, open-label study, adding milnacipran to pregabalin improved global status, pain, and other symptoms in patients with fibromyalgia with an incomplete response to pregabalin treatment.

Factors associated with the pressure pain threshold in healthy Chinese men

OBJECTIVE

The goal of present study was to examine the influence of demographic characteristics, lifestyle, and metabolic factors on pressure-induced pain threshold.

DESIGN AND SETTING

The study population comprised 2,517 healthy men at second-phase recruitment of a population-based cohort in China. The pressure pain threshold (PPT) at two locations, triceps and inguinal lines, was obtained using a digital pressure algometer. Education and occupation, as well as lifestyle factors, were self-reported in a face-to-face interview. Blood lipid and fasting glucose were measured as a routine healthy check-up program.

RESULTS

A lower PPT was found among men with younger age, higher level of education, and non-manual occupation. In addition, men with central obesity and moderate leisure time physical exercise were more sensitive to muscle mechanical stimuli. PPT was significantly correlated with high-density lipoprotein cholesterol (β for triceps = 0.064, and β for inguinal lines = 0.052) in a multivariate linear regression model, after controlling for multiple variables. Elevated PPT was also found among subjects with hyperglycemia (both P for triceps and inguinal lines <0.001) and excess drinking (P for triceps = 0.005).

CONCLUSIONS

It is important for physicians and researchers to consider these variables when evaluating pain sensitivity in clinic and in research. The underling mechanisms between these factors and pressure pain perception are worthy of further exploration.

Efficacy and safety of medicinal plants or related natural products for fibromyalgia: a systematic review

To assess the effects of medicinal plants (MPs) or related natural products (RNPs) on fibromyalgia (FM) patients, we evaluate the possible benefits and advantages of MP or RNP for the treatment of FM based on eight randomized placebo-controlled trials (RCTs) involving 475 patients. The methodological quality of all studies included was determined according to JADAD and “Risk of Bias” with the criteria in the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0. Evidence suggests significant benefits of MP or RNP in sleep disruption, pain, depression, joint stiffness, anxiety, physical function, and quality of life. Our results demonstrated that MP or RNP had significant effects on improving the symptoms of FM compared to conventional drug or placebo; longer tests are required to determine the duration of the treatment and characterize the long-term safety of using MP, thus suggesting effective alternative therapies in the treatment of pain with minimized side effects.

Primary attributions in women suffering fibromyalgia emphasize the perception of a disruptive onset for a long-lasting pain problem

OBJECTIVE

Fibromyalgia (FM) is a chronic musculoskeletal pain disorder characterized by widespread pain. This study focuses on patients' attributions of illness and of symptom onset.

METHODS

Semi-structured interviews were conducted with 56 women to elicit patients' views on what triggered their FM. The transcripts of the interviews were analyzed using a classical indexing technique to identify key themes. Content analysis was performed by two independent coders.

RESULTS

Primary causal attributions fell into five categories: psychological problems (28 respondents); somatic concerns (N=12); violence/abuse during childhood (N=7), gynaecological/obstetrical problems (N=6), and fatigue (N=3). Patients' attributions were internal and external in the same proportions, more frequently unstable than stable, and more often described uncontrollable than controllable. Participants expressed decrements in self-esteem and feelings such as self-blame or despair; global perceptions of persistent pain and long-lasting problems, evoking chronicity and hopelessness; and low perceived control over their lives as well as beliefs that nothing can be done, thus increasing a feeling of guilt and vulnerability. Patients' narratives emphasized disruptive circumstances surrounding symptom onset.

CONCLUSION

Attributions often referred to the psychological dimension of the events surrounding FM onset, even though some of them also had a clear somatic dimension. Many narratives mentioned successive disruptive events and suggested an increasing loss of control. Addressing these illness representations may contribute to tailor the treatment and to help patients gain self-coherency by providing means to understand pain onset but also to guide future behaviours, particularly in terms of adjustment and help-seeking.