Cytokines play an aetiopathogenetic role in fibromyalgia: a hypothesis and pilot study

OBJECTIVE

To measure soluble factors having a possible role in fibromyalgia (FM) and compare the profiles of patients with recent onset of the syndrome with patients with chronic FM.

METHODS

The production of cytokines, cytokine-related molecules, and a CXC chemokine, interleukin (IL)-8, was examined. Fifty-six patients with FM (23 with <2 yr and 33 with >2 yr of symptoms) were compared with age- and sex-matched healthy controls. Cytokines and cytokine-related molecules were measured in sera and in supernatants of peripheral blood mononuclear cells (PBMC) that were incubated with and without lectins and phorbol myristate acetate (PMA).

RESULTS

No differences between FMS and controls were found by measuring IL-1beta, IL-2, IL-10, serum IL-2 receptor (sIL-2R), interferon gamma (IFN-gamma), and tumour necrosis factor alpha (TNF-alpha). Levels of IL-1R antibody (IL-1Ra) and IL-8 were significantly higher in sera, and IL-1Ra and IL-6 were significantly higher in stimulated and unstimulated FM PBMC compared with controls. Serum IL-6 levels were comparable to those in controls, but were elevated in supernatants of in vitro-activated PBMC derived from patients with >2 yr of symptoms. In the presence of PMA, there were additional increases in IL-1Ra, IL-8 and IL-6 over control values.

CONCLUSIONS

In patients with FM we found increases over time in serum levels and/or PBMC-stimulated activity of soluble factors whose release is stimulated by substance P. Because IL-8 promotes sympathetic pain and IL-6 induces hyperalgesia, fatigue and depression, it is hypothesized that they may play a role in modulating FM symptoms.

Functional mixed effects models

In this article, a new class of functional models in which smoothing splines are used to model fixed effects as well as random effects is introduced. The linear mixed effects models are extended to nonparametric mixed effects models by introducing functional random effects, which are modeled as realizations of zero-mean stochastic processes. The fixed functional effects and the random functional effects are modeled in the same functional space, which guarantee the population-average and subject-specific curves have the same smoothness property. These models inherit the flexibility of the linear mixed effects models in handling complex designs and correlation structures, can include continuous covariates as well as dummy factors in both the fixed or random design matrices, and include the nested curves models as special cases. Two estimation procedures are proposed. The first estimation procedure exploits the connection between linear mixed effects models and smoothing splines and can be fitted using existing software. The second procedure is a sequential estimation procedure using Kalman filtering. This algorithm avoids inversion of large dimensional matrices and therefore can be applied to large data sets. A generalized maximum likelihood (GML) ratio test is proposed for inference and model selection. An application to comparison of cortisol profiles is used as an illustration.

Increased matrix metalloproteinase-3 serum levels in rheumatic diseases: relationship with synovitis and steroid treatment

OBJECTIVE

To determine matrix metalloproteinase-3 (MMP-3) serum levels in patients with rheumatic diseases and to study the relation between MMP-3 and C reactive protein (CRP) levels.

METHODS

MMP-3 serum levels were determined by enzyme linked immunosorbent assay (ELISA) in (a) patients with active inflammatory rheumatic diseases: rheumatoid arthritis (RA), psoriatic arthritis, polymyalgia rheumatica, acute crystal arthritis, and ankylosing spondylitis; (b) patients with active inflammatory systemic diseases: cutaneo-articular or renal systemic lupus erythematosus (SLE), systemic sclerosis, and vasculitides; (c) patients with non-inflammatory rheumatic diseases: osteoarthritis and fibromyalgia; (d) critically ill patients without rheumatic diseases, representing an acute inflammatory control group; (e) healthy controls.

RESULTS

MMP-3 serum levels were significantly increased in patients with active RA, psoriatic arthritis, and polymyalgia rheumatica, whether treated or not by corticosteroids, and in female patients with acute crystal arthritis. MMP-3 serum levels were normal in steroid-free patients with active cutaneo-articular or renal SLE, systemic sclerosis, and vasculitides but were significantly increased in steroid treated patients. MMP-3 levels were normal in fibromyalgia, osteoarthritis, ankylosing spondylitis, and acute inflammatory controls. MMP-3 was significantly correlated with CRP in RA (r=0.5, p=0.0004) but not in any of the other disease groups.

CONCLUSIONS

MMP-3 serum levels are increased in inflammatory rheumatic diseases characterised by joint synovitis, such as RA, polymyalgia rheumatica, psoriatic arthritis, and acute crystal arthritis-that is, whether the diseases are acute or chronic, erosive or not. They are normal in SLE, systemic sclerosis, and vasculitides as well as in non-rheumatic inflammatory controls, but are significantly increased by steroids. These data strongly suggest that serum MMP-3 reflects synovial inflammation.

Low levels of somatomedin C in patients with the fibromyalgia syndrome. A possible link between sleep and muscle pain

OBJECTIVE

Fibromyalgia is a common syndrome of musculoskeletal pain and fatigue. Lacking distinctive tissue or laboratory correlations, it has often been considered a form of "psychogenic rheumatism." In the present study, the notion that the stage-4 sleep anomaly typically seen in the fibromyalgia syndrome may disrupt growth hormone secretion was tested. Because growth hormone has a very short half-life, serum levels of somatomedin C were measured; somatomedin C is the major mediator of growth hormone's anabolic actions and is a prerequisite for normal muscle homeostasis.

METHODS

Serum levels of somatomedin C were measured in 70 female fibromyalgia patients and 55 healthy controls, using a peptide-specific radioimmunoassay.

RESULTS

Significantly lower levels of somatomedin C were observed in the fibromyalgia patients compared with controls (mean +/- SD 124.7 +/- 47 ng/ml versus 175.2 +/- 60 ng/ml; P = 0.000001). These results could not be explained by concomitant therapy or by weight, and in a subset of 21 patients in whom this was investigated, there was no correlation with various indices of disease activity.

CONCLUSION

These findings indicate that there is a distinctive disruption of the growth hormone-somatomedin C neuroendocrine axis in a majority of fibromyalgia patients. It is hypothesized that this abnormality may explain the link between disturbed sleep and predisposition to muscle pain.

Basal circadian and pulsatile ACTH and cortisol secretion in patients with fibromyalgia and/or chronic fatigue syndrome

The objective of this study was to evaluate and compare the basal circadian and pulsatile architecture of the HPA axis in groups of patients with FMS, CFS, or both syndromes with individually matched control groups. Forty patients with either FMS (n = 13), FMS and CFS (n = 12), or CFS (n = 15) were matched by age (18-65), sex, and menstrual status to healthy controls. Subjects were excluded if they met criteria for major Axis I psychiatric disorders by structured clinical interview (SCID). Subjects were admitted to the General Clinical Research Center where meals and activities were standardized. Blood was collected from an intravenous line every 10 min over 24 h for analysis of ACTH and cortisol. Samples were evaluable for ACTH in 36 subject pairs and for cortisol in 37 subject pairs. There was a significant delay in the rate of decline from acrophase to nadir for cortisol levels in patients with FMS (P <.01). Elevation of cortisol in the late evening quiescent period was evident in half of the FMS patients compared with their control group, while cortisol levels were numerically, but not significantly, lower in the overnight period in patients with CFS compared with their control group. Pulsatility analyses did not reveal statistically significant differences between patient and control groups. We conclude that the pattern of differences for basal circadian architecture of HPA axis hormones differs between patients with FMS and CFS compared to their matched control groups. The abnormalities in FMS patients are consistent with loss of HPA axis resiliency.

Low serum 25 (OH) vitamin D levels (<32 ng/mL) are associated with reversible myositis-myalgia in statin-treated patients

Our specific aims were to determine whether low serum 25 (OH) vitamin D (D2 + D3) (<32 ng/mL) was associated with myalgia in statin-treated patients and whether the myalgia could be reversed by vitamin D supplementation while continuing statins. After excluding subjects who took corticosteroids or supplemental vitamin D, serum 25 (OH) D was measured in 621 statin-treated patients, which consisted of 128 patients with myalgia at entry and 493 asymptomatic patients. The 128 myalgic patients had lower mean +/- standard deviation (SD) serum vitamin D than the 493 asymptomatic patients (28.6 +/- 13.2 vs 34.2 +/- 13.8 ng/mL, P < 0.0001), but they did not differ (p > 0.05) by age, body mass index (BMI), type 2 diabetes, or creatine kinase levels. By analysis of variance, which was adjusted for race, sex, and age, the least square mean (+/- standard error [SE]) serum vitamin D was lower in the 128 patients with myalgia than in the 493 asymptomatic patients (28.7 +/- 1.2 vs 34.3 +/- 0.6 ng/mL, P < 0.0001). Serum 25 (OH) D was low in 82 of 128 (64%) patients with myalgia versus 214 of 493 (43%) asymptomatic patients (chi(2) = 17.4, P < 0.0001). Of the 82 vitamin-D-deficient, myalgic patients, while continuing statins, 38 were given vitamin D (50,000 units/week for 12 weeks), with a resultant increase in serum vitamin D from 20.4 +/- 7.3 to 48.2 +/- 17.9 ng/mL (P < 0.0001) and resolution of myalgia in 35 (92%). We speculate that symptomatic myalgia in statin-treated patients with concurrent vitamin D deficiency may reflect a reversible interaction between vitamin D deficiency and statins on skeletal muscle.

A randomized, double-blind, placebo-controlled study of growth hormone in the treatment of fibromyalgia

PURPOSE

The cause of fibromyalgia (FM) is not known. Low levels of insulin-like growth factor 1 (IGF-1), a surrogate marker for low growth hormone (GH) secretion, occur in about one third of patients who have many clinical features of growth hormone deficiency, such as diminished energy, dysphoria, impaired cognition, poor general health, reduced exercise capacity, muscle weakness, and cold intolerance. To determine whether suboptimal growth hormone production could be relevant to the symptomatology of fibromyalgia, we assessed the clinical effects of treatment with growth hormone.

METHODS

Fifty women with fibromyalgia and low IGF-1 levels were enrolled in a randomized, placebo-controlled, double-blind study of 9 months' duration. They gave themselves daily subcutaneous injections of growth hormone or placebo. Two outcome measures--the Fibromyalgia Impact Questionnaire and the number of fibromyalgia tender points-were evaluated at 3-monthly intervals by a blinded investigator. An unblinded investigator reviewed the IGF-1 results monthly and adjusted the growth hormone dose to achieve an IGF-1 level of about 250 ng/mL.

RESULTS

Daily growth hormone injections resulted in a prompt and sustained increase in IGF-1 levels. The treatment (n=22) group showed a significant improvement over the placebo group (n=23) at 9 months in both the Fibromyalgia Impact Questionnaire score (P <0.04) and the tender point score (P <0.03). Fifteen subjects in the growth hormone group and 6 subjects in the control group experienced a global improvement (P <0.02). There was a delayed response to therapy, with most patients experiencing improvement at the 6-month mark. After discontinuing growth hormone, patients experienced a worsening of symptoms. Carpal tunnel symptoms were more prevalent in the growth hormone group (7 versus 1); no other adverse events were more common in this group.

CONCLUSIONS

Women with fibromyalgia and low IGF-1 levels experienced an improvement in their overall symptomatology and number of tender points after 9 months of daily growth hormone therapy. This suggests that a secondary growth hormone deficiency may be responsible for some of the symptoms of fibromyalgia.

Regional cerebral blood flow in fibromyalgia: single-photon-emission computed tomography evidence of reduction in the pontine tegmentum and thalami

OBJECTIVE

To determine whether regional cerebral blood flow (rCBF) is abnormal in any cerebral structure of women with fibromyalgia (FM), following a report that rCBF is reduced in the thalami and heads of caudate nuclei in FM.

METHODS

Seventeen women with FM and 22 healthy women had a resting single-photon-emission computed tomography (SPECT) brain scan to assess rCBF and a T1-weighted magnetic resonance imaging (MRI) scan to enable precise anatomic localization. Additionally, all participants underwent 2 manual tender point examinations and completed a set of questionnaires evaluating clinical features. SPECT scans were analyzed for differences in rCBF between groups using statistical parametric mapping (SPM) and regions of interest (ROIs) manually drawn on coregistered MRI.

RESULTS

Compared with control subjects, the rCBF in FM patients was significantly reduced in the right thalamus (P = 0.006), but not in the left thalamus or head of either caudate nucleus. SPM analysis indicated a statistically significant reduction in rCBF in the inferior pontine tegmentum (corrected P = 0.006 at the cluster level and corrected P = 0.023 for voxel of maximal significance), with consistent findings from ROI analysis (P = 0.003). SPM also detected a reduction in rCBF on the perimeter of the right lentiform nucleus. No correlations were found with clinical features or indices of pain threshold.

CONCLUSION

Our finding of a reduction in thalamic rCBF is consistent with findings of functional brain imaging studies of other chronic clinical pain syndromes, while our finding of reduced pontine tegmental rCBF is new. The pathophysiologic significance of these changes in FM remains to be elucidated.

Free radicals and antioxidants in primary fibromyalgia: an oxidative stress disorder?

The role of free radicals in fibromyalgia is controversial. In this study, 85 female patients with primary fibromyalgia and 80 age-, height-, and weight-matched healthy women were evaluated for oxidant/antioxidant balance. Malondialdehyde is a toxic metabolite of lipid peroxidation used as a marker of free radical damage. Superoxide dismutase is an intracellular antioxidant enzyme and shows antioxidant capacity. Pain was assessed by visual analog scale. Tender points were assessed by palpation. Age, smoking, body mass index (BMI), and duration of disease were also recorded. Malondialdehyde levels were significantly higher and superoxide dismutase levels significantly lower in fibromyalgic patients than controls. Age, BMI, smoking, and duration of disease did not affect these parameters. We found no correlation between pain and number of tender points. In conclusion, oxidant/antioxidant balances were changed in fibromyalgia. Increased free radical levels may be responsible for the development of fibromyalgia. These findings may support the hypothesis of fibromyalgia as an oxidative disorder.

Reduced hypothalamic-pituitary and sympathoadrenal responses to hypoglycemia in women with fibromyalgia syndrome

PURPOSE

To perform a detailed comparison of the hypothalamic-pituitary-adrenal axis and the sympathoadrenal system in women with and without fibromyalgia.

SUBJECTS AND METHODS

Fifteen premenopausal women who met the 1990 American College of Rheumatology criteria for the diagnosis of fibromyalgia and 13 healthy, premenopausal women were enrolled. We measured baseline 24-hour urinary free cortisol levels and evening and morning adrenocorticotropic hormone (ACTH) and cortisol levels, performed stepped hypoglycemic hyperinsulinemic clamp studies in which serum glucose levels were decreased from 5.0 to 2.2 mmol/L, and compared the effects of infusions of placebo and ACTH.

RESULTS

Women with fibromyalgia had normal 24-hour urinary free cortisol levels and normal diurnal patterns of ACTH and cortisol. There was a significant, approximately 30%, reduction in the ACTH and epinephrine responses to hypoglycemia in women with fibromyalgia compared with controls. Prolactin, norepinephrine, cortisol, and dehydroepiandrosterone responses to hypoglycemia were similar in the two study groups. In subjects with fibromyalgia, the epinephrine response to hypoglycemia correlated (P = 0.01) inversely with overall health status as measured by the fibromyalgia impact questionnaire. Graded ACTH infusion revealed similar increases in cortisol in women with fibromyalgia and healthy controls.

CONCLUSIONS

Patients with fibromyalgia have an impaired ability to activate the hypothalamic-pituitary portion of the hypothalamic-pituitary-adrenal axis as well as the sympathoadrenal system, leading to reduced ACTH and epinephrine responses to hypoglycemia.

Pain treatment of fibromyalgia by acupuncture

The lack of objective parameters makes the measurement of pain and the efficacy of pain treatment in patients with chronic pain very difficult. We performed acupuncture therapy in fibromyalgia patients and established a combination of methods to objectify pain measurement before and after therapy. The parameters corresponded to patients' self-report. Twenty-nine fibromyalgia patients as defined by ACR-criteria (25 women, 4 men) with a mean age of 48.2 +/- 2.0 years and a mean disease duration of 6.1 +/- 1.0 years participated in the study. Pain levels and positive tender points were assessed using the visual analogue scale (VAS, i.e., range 0-100 mm) and dolorimetry. Serotonin and substance P levels in serum and the serotonin concentration in platelets were measured concomitantly. During acupuncture therapy no analgesic medication was allowed. The VAS scores decreased from 64.0 +/- 3.4 mm before therapy to 34.5 +/- 4.3 mm after therapy (P < 0.001). Dolorimetry revealed a decreased number of tender points after therapy from 16.0 +/- 0.6 to 11.8 +/- 1.0, P < 0.01. Serotonin levels decreased from 715.8 +/- 225.8 micrograms/10(12) platelets to 352.4 +/- 47.9 micrograms/10(12) platelets (P < 0.01), whereas the serum concentration increased from 134.0 +/- 14.3 ng/ml to 171.2 +/- 14.6 ng/ml (P < 0.01). Substance P levels in serum increased from 43.4 +/- 3.5 pg/ml to 66.9 +/- 8.8 pg/ml (P < 0.01). Acupuncture treatment of patients with fibromyalgia was associated with decreased pain levels and fewer positive tender points as measured by VAS and dolorimetry. This was accompanied by decreased serotonin concentration in platelets and an increase of serotonin and substance P levels in serum. These results suggest that acupuncture therapy is associated with changes in the concentrations of pain-modulating substances in serum. The preliminary results are objective parameters for acupuncture efficacy in patients with fibromyalgia.

A 37 kDa 2-5A binding protein as a potential biochemical marker for chronic fatigue syndrome

PURPOSE

Recent studies have revealed abnormalities in the ribonuclease L pathway in peripheral blood mononuclear cells of patients with the chronic fatigue syndrome. We conducted a blinded study to detect possible differences in the distribution of 2-5A binding proteins in the cells of patients with chronic fatigue syndrome and controls.

PATIENTS AND METHODS

We studied 57 patients with chronic fatigue syndrome and 53 control subjects (28 healthy subjects and 25 patients with depression or fibromyalgia). A radioactive probe was used to label 2-5A binding proteins in unfractionated peripheral blood mononuclear cell extracts and to compare their distribution in the three groups.

RESULTS

A 37 kDa 2-5A binding polypeptide was found in 50 (88%) of the 57 patients with chronic fatigue syndrome compared with 15 (28%) of the 53 controls (P < 0.01). When present, the amount of 37 kDa protein was very low in the control groups. When expressed as the ratio of the 37 kDa protein to the 80 kDa protein, 41 (72%) of the 57 patients with chronic fatigue syndrome had a ratio > 0.05, compared with 3 (11%) of the 28 healthy subjects and none of the patients with fibromyalgia or depression.

CONCLUSION

The presence of a 37 kDa 2-5A binding protein in extracts of peripheral blood mononuclear cells may distinguish patients with chronic fatigue syndrome from healthy subjects and those suffering from other diseases.

Plasma tryptophan and musculoskeletal pain in non-articular rheumatism ("fibrositis syndrome")

Plasma-free tryptophan is inversely related to the severity of subjective pain in 8 patients who fulfilled criteria for a variety of non-articular rheumatism, the "fibrositis syndrome". The observation is consistent with animal and human studies suggesting a relationship between reduced brain serotonin metabolism and pain reactivity.

IL-8 and IL-6 primarily mediate the inflammatory response in fibromyalgia patients

Fibromyalgia (FM) is a chronic disease that has been linked to inflammatory reactions and changes in the systemic levels of proinflammatory cytokines that modulate responses in the sympathetic nervous system and hypothalamic-pituitary-adrenal axis. We found that concentrations of IL-6 and IL-8 were elevated in FM patients. Both cytokines correlated with clinical scores, suggesting that IL-6 and IL-8 have additive or synergistic effects in perpetuating the chronic pain in FM patients. These findings indicate that IL-6 and IL-8 are two of the most constant inflammatory mediators in FM and that their levels correlate significantly with the severity of symptoms.

Physiological effects of exhaustive physical exercise in primary fibromyalgia syndrome (PFS): is PFS a disorder of neuroendocrine reactivity?

The influence of maximum exercise has been studied in 10 patients with primary fibromyalgia syndrome (PFS) and 10 healthy sedentary control persons. The exercise consisted of a bicycle ergometertest and a steptest, both till exhaustion. In both tests, the mean maximum workload of the PFS patients was lower than that of the controls. Significantly lower values of serum creatinekinase, myoglobin, cortisol, epinephrine and norepinephrine were found in PFS patients. A striking finding was a lower heart rate in PFS patients compared to the controls under the same workload. The lower (nor)epinephrine concentration together with the lower heart rate suggests a disturbance of the sympathetic activity in PFS patients. The preliminary conclusion is that there is a disturbed reactivity of the sympathetic system as well as of the HPA axis in PFS.

Increased BDNF serum concentration in fibromyalgia with or without depression or antidepressants

Fibromyalgia (FM) is still often viewed as a psychosomatic disorder. However, the increased pain sensitivity to stimuli in FM patients is not an "imagined" histrionic phenomena. Pain, which is consistently felt in the musculature, is related to specific abnormalities in the CNS pain matrix. Brain-derived neurotrophic factor (BDNF) is an endogenous protein involved in neuronal survival and synaptic plasticity of the central and peripheral nervous system (CNS and PNS). Several lines of evidence converged to indicate that BDNF also participates in structural and functional plasticity of nociceptive pathways in the CNS and within the dorsal root ganglia and spinal cord. In the latter, release of BDNF appears to modulate or even mediate nociceptive sensory inputs and pain hypersensitivity. We were interested, if BDNF serum concentration may be altered in FM. The present pilot study assessed to our knowledge for the first time BDNF serum concentrations in 41 FM patients in comparison to 45 age-matched healthy controls. Mean serum levels of BDNF in FM patients (19.6 ng/ml; SD 3.1) were significantly increased as compared to healthy controls (16.8 ng/ml; SD 2.7; p<0.0001). In addition, BDNF serum concentrations in FM patients were independent from age, gender, illness duration, preexisting recurrent major depression and antidepressive medication in low doses. In conclusion, the results from our study indicate that BDNF may be involved in the pathophysiology of pain in FM. Nevertheless, how BDNF increases susceptibility to pain is still not known.

Evaluating obesity in fibromyalgia: neuroendocrine biomarkers, symptoms, and functions

The aim of this study was to investigate the associations between obesity and fibromyalgia syndrome (FMS). This study was conducted at the University of Utah Pain Management and Research Center, Salt Lake City, Utah. Thirty-eight FMS patients were included in this study. Neuroendocrine indices (catecholamines, cortisol, C-reactive protein [CRP], and interleukin-6), symptom measures (Fibromyalgia Impact Questionnaire), sleep indices (Actigraph), and physical functioning (treadmill testing) were measured. Body mass index (BMI) provided the primary indicator of obesity. Approximately 50% of the patients were obese and an additional 21% were overweight. Strong positive associations were found between BMI and levels of IL-6 (r=0.52) and epinephrine (r=0.54), and somewhat weaker associations with cortisol (r=0.32) and CRP (r=0.37). BMI was also related to maximal heart rate (r=0.33) and inversely related to distance walked (r= -0.41). BMI was associated with disturbed sleep: total sleep time (r= -0.56) and sleep efficiency (r= -0.44). No associations between self-reported symptoms and BMI were found. This study provides preliminary evidence suggesting that obesity plays a role in FMS-related dysfunction.

The "chronic, active Epstein-Barr virus infection" syndrome and primary fibromyalgia

Fifty patients with primary fibromyalgia who had been followed in an academic rheumatology practice frequently reported symptoms thought to be typical of "chronic Epstein-Barr virus infection," but not of fibromyalgia: recurrent sore throat (54%), recurrent rash (47%), chronic cough (40%), recurrent adenopathy (33%), and recurrent low-grade fevers (28%). In 55% of the patients, illness had begun suddenly, with what seemed to be a viral syndrome. Antibody titers to Epstein-Barr virus in the patients with fibromyalgia, however, were not significantly different from those in age- and sex-matched "healthy" and "unhealthy" control subjects.

Neuropeptides CRH, SP, HK-1, and Inflammatory Cytokines IL-6 and TNF Are Increased in Serum of Patients with Fibromyalgia Syndrome, Implicating Mast Cells

Fibromyalgia syndrome (FMS) is a chronic, idiopathic condition of widespread musculoskeletal pain affecting more women than men. Even though clinical studies have provided evidence of altered central pain pathways, the lack of definitive pathogenesis or reliable objective markers has hampered development of effective treatments. Here we report that the neuropeptides corticotropin-releasing hormone (CRH), substance P (SP), and SP-structurally-related hemokinin-1 (HK-1) were significantly (P = 0.026, P < 0.0001, and P = 0.002, respectively) elevated (0.82 ± 0.57 ng/ml, 0.39 ± 0.18 ng/ml, and 7.98 ± 3.12 ng/ml, respectively) in the serum of patients with FMS compared with healthy controls (0.49 ± 0.26 ng/ml, 0.12 ± 0.1 ng/ml, and 5.71 ± 1.08 ng/ml, respectively). Moreover, SP and HK-1 levels were positively correlated (Pearson r = 0.45, P = 0.002) in FMS. The serum concentrations of the inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF) were also significantly (P = 0.029 and P = 0.006, respectively) higher (2.97 ± 2.35 pg/ml and 0.92 ± 0.31 pg/ml, respectively) in the FMS group compared with healthy subjects (1.79 ± 0.62 pg/ml and 0.69 ± 0.16 pg/ml, respectively). In contrast, serum IL-31 and IL-33 levels were significantly lower (P = 0.0001 and P = 0.044, respectively) in the FMS patients (849.5 ± 1005 pg/ml and 923.2 ± 1284 pg/ml, respectively) in comparison with healthy controls (1281 ± 806.4 pg/ml and 3149 ± 4073 pg/ml, respectively). FMS serum levels of neurotensin were not different from controls. We had previously shown that CRH and SP stimulate IL-6 and TNF release from mast cells (MCs). Our current results indicate that neuropeptides could stimulate MCs to secrete inflammatory cytokines that contribute importantly to the symptoms of FMS. Treatment directed at preventing the secretion or antagonizing these elevated neuroimmune markers, both centrally and peripherally, may prove to be useful in the management of FMS.

Cerebrospinal fluid biogenic amine metabolites, plasma-rich platelet serotonin and [3H]imipramine reuptake in the primary fibromyalgia syndrome

BACKGROUND

Primary fibromyalgia syndrome (PFS) is a chronic disorder commonly seen in rheumatological practice. The pathophysiological disturbances of this syndrome, which was defined by the American College of Rheumatology in 1990, are poorly understood. This study evaluated, in 30 patients, the hypothesis that PFS is a pain modulation disorder induced by deregulation of serotonin metabolism.

OBJECTIVES

To compare platelet [(3)H]imipramine binding sites and serotonin (5-HT) levels in plasma-rich platelets (PRP) of PFS patients with those of matched healthy controls and to compare the levels of biogenic amine metabolites in the cerebrospinal fluid (CSF) of PFS patients with those of matched controls.

METHODS

Platelet [(3)H]imipramine binding sites were defined by two criteria, B(max) for their density and K(d) for their affinity. PRP 5-HT and CSF metabolites of 5-HT (5-hydroxyindoleacetic acid, 5-HIAA), norepinephrine (3-methoxy, 4-hydroxy phenylglycol, MHPG) and dopamine (homovanillic acid, HVA) were assayed by reversed-phase high-performance liquid chromatography with coulometric detection.

RESULTS

[(3)H]Imipramine platelet binding was similar (P=0.43 for B(max) and P=0.30 for K(d)) in PFS patients (B(max)=901+/-83 fmol/mg protein, K(d)=0.682+/-0.046) and in matched controls (B(max)=1017+/-119 fmol/mg protein, K(d)=0.606+/-0.056). PRP 5-HT was significantly higher (P=0.0009) in PFS patients (955+/-101 ng/10(9) platelets) than in controls (633+/-50 ng/10(9) platelets). When adjusted for age, the levels of all CSF metabolites were lower in PFS patients. The CSF metabolite of norepinephrine (MHPG) was lower (P:=0.003) in PFS patients (8.33+/-0.33 ng/ml) than in matched controls (9.89+/-0.31 ng/ml) and 5-HIAA was lower (P=0.042) in PFS female patients (22.34+/-1.78 ng/ml) than in matched controls (25.75+/-1.75 ng/ml). For HVA in females, the difference between PFS patients (36.32+/-3.20 ng/ml) and matched controls (38.32+/-2.90 ng/ml) approached statistical significance (P=0.054).

CONCLUSION

Changes in metabolites of CSF biogenic amines appear to be partially correlated to age but remained diagnosis-dependent. High levels of PRP 5-HT in PFS patients were associated with low CSF 5-HIAA levels in female patients but were not accompanied by any change in serotonergic uptake as assessed by platelet [(3)H]imipramine binding sites. These findings do not allow us to confirm that serotonin metabolism is deregulated in PFS patients.

Plasma oxytocin levels in female fibromyalgia syndrome patients

OBJECTIVES

Fibromyalgia syndrome (FMS) is a chronic pain disorder, where 90% of the patients struck by the disorder are women. The neuropeptide oxytocin is known to have antinociceptive and analgesic, as well as anxiolytic and antidepressant effects, which makes this neuropeptide of interest in fibromyalgia research. The aim of this study was to assess oxytocin concentrations in female FMS patients with different hormonal status and in depressed and non-depressed patients and relate oxytocin concentrations to adverse symptoms as pain, stress, depression, anxiety and to the positive item happiness.

METHODS

Thirty-nine patients and 30 controls registered these symptoms daily during 28 days and blood samples for the assessment of oxytocin were drawn twice in all patients and controls. Besides the daily ratings, depression was also estimated with the self-rating instrument Beck Depression Inventory (BDI).

RESULTS

Depressed patients according to the BDI differed significantly with low levels of oxytocin compared to the non-depressed patients and the controls. Low levels of oxytocin were also seen in high scoring pain, stress and depression patients according to the daily ratings; however, these subgroups were small. A negative correlation was found between the scored symptoms depression and anxiety and oxytocin concentration, and a positive correlation between the item happiness and oxytocin. The oxytocin concentration did not differ between the hormonally different subgroups of patients or controls.

CONCLUSION

The results suggest that the neuropeptide oxytocin may, together with other neuropeptides and neurotransmitters, play a role in the integration of the stress axes, monoaminergic systems and the pain processing peptides in the pathophysiologic mechanisms responsible for the symptoms in the FMS.

Evaluation of the impact of concomitant fibromyalgia on TNF alpha blockers' effectiveness in axial spondyloarthritis: results of a prospective, multicentre study

OBJECTIVE

To describe the prevalence of fibromyalgia (FM) in an axial spondyloarthritis (axSpA) population and to confirm that concomitant FM had a negative impact on tumour necrosis factor blockers' (TNFb) response.

DESIGN

Prospective observational study with two visits 3 months apart.

PATIENTS

Adult patients with AxSpa initiating a TNFb.

STUDY GROUPS

FM was defined by the Fibromyalgia Rapid Screening Tool (FiRST) at baseline and also by a sustained positive FiRST (both visits) and by a fulfilment of the 1990 American College of Rheumatology criteria for FM.

STATISTICAL ANALYSIS

Prevalence of FM; evaluation of the impact of a concomitant FM on TNFb response (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI 50) as primary endpoint), adjusted by factors known to have an impact on TNFb response.

RESULTS

Among the 508 patients included in the main analysis, 192 (37.8%) were screened at baseline as FM. Percentage of success after 12 weeks of treatment was lower in the FM group for most of the effectiveness endpoints (eg, BASDAI 50: 45.3% vs 54.1% in the FM/not FM groups according to the FiRST), except for the C reactive protein change endpoints which were not different across groups.

CONCLUSION

This study confirms that FM coexists in patients with axSpA and that its presence seems to have a negative impact on TNFb response, which seems more related to the self-reported instruments used in its evaluation, rather than a different treatment effect of the molecule in this subgroup of patients.

Relationship of substance P, 5-hydroxyindole acetic acid and tryptophan in serum of fibromyalgia patients

The serotonergic system has repeatedly been discussed to be involved in the pathophysiology of fibromyalgia (FM), which is a syndrome of widespread pain and sleep disturbance. Elevated levels of substance P (SP), a mediator of nociception, have been described in FM. In this study the possible relationship between SP and serotonin (5-HT) together with its precursor tryptophan (TRP) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) was evaluated in 51 serum samples of fibromyalgia patients. These parameters were compared with clinical data such as pain intensity or sleep quality. A strong negative correlation between SP and 5-HIAA (P = .000) as well as between SP and TRP (P = .009) could be demonstrated. High serum concentrations of 5-HIAA and TRP showed a significant relation to low pain scores (5-HIAA: P = .030; TRP: P = .014). Moreover, 5-HIAA was strongly related to good quality of sleep (P = .000), while SP was related to sleep disturbance (P = .005). These data are valid to support the hypothesis of a systemic involvement of 5-HT and SP in fibromyalgia.

Fibromyalgia: anti-inflammatory and stress responses after acute moderate exercise

Fibromyalgia (FM) is characterized in part by an elevated inflammatory status, and "modified exercise" is currently proposed as being a good therapeutic help for these patients. However, the mechanisms involved in the exercise-induced benefits are still poorly understood. The objective was to evaluate the effect of a single bout of moderate cycling (45 min at 55% VO2 max) on the inflammatory (serum IL-8; chemotaxis and O2 (-) production by neutrophils; and IL-1β, TNF-α, IL-6, IL-10, and IL-18 release by monocytes) and stress (cortisol; NA; and eHsp72) responses in women diagnosed with FM compared with an aged-matched control group of healthy women (HW). IL-8, NA, and eHsp72 were determined by ELISA. Cytokines released by monocytes were determined by Bio-Plex® system (LUMINEX). Cortisol was determined by electrochemoluminiscence, chemotaxis was evaluated in Boyden chambers and O2 (-) production by NBT reduction. In the FM patients, the exercise induced a decrease in the systemic concentration of IL-8, cortisol, NA, and eHsp72; as well as in the neutrophil's chemotaxis and O2 (-) production and in the inflammatory cytokine release by monocytes. This was contrary to the completely expected exercise-induced increase in all those biomarkers in HW. In conclusion, single sessions of moderate cycling can improve the inflammatory status in FM patients, reaching values close to the situation of aged-matched HW at their basal status. The neuroendocrine mechanism seems to be an exercise-induced decrease in the stress response of these patients.

Sex hormones and pain in regularly menstruating women with fibromyalgia syndrome

Fibromyalgia syndrome (FMS) is more prevalent in women than in men. The skewed sex distribution in the prevalence has prompted questions of if and how sex hormones may be involved in the pathophysiology of FMS. In this study, we evaluated the levels of sex hormones and pain sensitivity at different phases of a menstrual cycle in regularly menstruating women with FMS relative to age-matched healthy women. Participants (n = 74 in each group) underwent a 9-day urine test to identify the date of ovulation. Three laboratory visits were scheduled to ascertain the varying levels of estrogen (E) and progesterone (P): Late-follicular phase (high E, low P); mid-luteal phase (high E, high P); and perimenstrual phase (low E, low P). At each visit, blood was drawn and ischemic pain testing was performed. The groups did not differ in the fluctuation of luteal hormone, follicular-stimulating hormone, E, and testosterone across a menstrual cycle. FMS patients showed slightly elevated P levels during the mid-luteal phase relative to healthy women but levels were within the normal range. Women with FMS showed consistently lower pain thresholds and tolerance relative to healthy women throughout the menstrual cycle. Pain threshold at the late follicular phase was modestly related to the P level. The results suggest that the disproportionate prevalence of females with FMS is not likely to be attributable to hormonal factors. Furthermore, the role of sex hormones in pain sensitivity for both FMS and healthy women seems to be limited.

PERSPECTIVE

Normally menstruating women with FMS and healthy women do not seem to show fluctuating threshold and tolerance to the ischemic pain test. The role of sex hormones in the hyperalgesia of FMS appears limited.