Blunted ACTH and cortisol responses to systemic injection of corticotropin-releasing hormone (CRH) in fibromyalgia: role of somatostatin and CRH-binding protein

Association of circulating leptin, growth hormone, and ghrelin with fibromyalgia: A meta-analysis

OBJECTIVE

The aim of this study was to evaluate the relationship between levels of leptin, growth hormone (GH), and ghrelin in the bloodstream and fibromyalgia.

METHODS

We conducted a meta-analysis to compare the serum/plasma levels of leptin, GH, and ghrelin in individuals with fibromyalgia, as compared to healthy controls. The analysis included sixteen articles, which provided data from 697 fibromyalgia patients and 560 controls.

RESULTS

The meta-analysis found that there was no significant difference in leptin levels between fibromyalgia patients and controls overall (SMD = 0.324, 95% CI = -0.264 to 0.913, P = 0.281). However, when subgroup analysis was done based on geographically different populations, it showed a positive association between high leptin levels and fibromyalgia in European populations (SMD = 1.131, 95% CI = 0.197 to 2.064, P = 0.018), while no significant association was found in Latin American populations (SMD = -0.160, 95% CI = -0.847 to 0.528, P = 0.649). As for GH levels, there was no significant difference between fibromyalgia patients and controls overall (SMD = -0.903, 95% CI = -2.036 to 0.231, P = 0.119). However, when subgroup analysis was done based on geographically different populations, it revealed a significant decrease in GH levels in European populations with fibromyalgia (SMD = -2.341, 95% CI = -3.664 to -1.017, P = 0.001), while no significant association was found in North American populations. Lastly, the analysis of ghrelin levels showed no significant association with fibromyalgia overall (SMD = -0.661, 95% CI = -1.382 to 0.059, P = 0.072).

CONCLUSION

This meta-analysis shows that patients with fibromyalgia in Europeans have significantly higher levels of circulating leptin and GH. However, no significant association was found between ghrelin levels and fibromyalgia.

Can an Aerobic Exercise Programme Improve the Response of the Growth Hormone in Fibromyalgia Patients? A Randomised Controlled Trial

Downgrade alterations in the growth hormone (GH) might be involved in the development of some of the fibromyalgia syndrome (FMS) symptoms. Our aim was to assess the effects of an aerobic exercise programme on the GH levels in patients with FMS. A randomised controlled trial was developed. Sixty-four Spanish women with FMS were randomly assigned to the experimental arm (n = 33) and treated with a 16-week group physical exercise programme based on low impact aerobic dance (three weekly sessions, one-hour each), or to the treatment-as-usual (TAU) control arm (n = 31). The primary outcome was the GH response to acute exercise. Secondary outcomes were GH basal, sensitivity to pain, body composition, aerobic capacity, and quality of life. The ANCOVA results showed a moderate effect of treatment improving the GH response to acute exercise. Other effects were substantial for aerobic capacity, quality of life, and body composition. Pre-intervention GH response to acute exercise was related to improvements in aerobic capacity and quality of life. An aerobic exercise programme may improve the response of the GH, aerobic capacity, body composition, and quality of life in women with FMS. The normalization of neuro-hormonal patterns involving the GH might be key for improving some FMS symptoms.

Neurohumoral Profiles and Childhood Adversity of Patients with Multisomatoform Disorder and Pain as the Leading Bodily Symptom

Objective

Patients suffering from chronic pain often present with multifactorial underlying conditions, sometimes without concrete pathological physical findings. Functional somatic syndromes (FSS) and somatoform disorders show a high prevalence of 8-20% and are often associated with adverse childhood experiences (ACE) and chronic stress. As many different FSS have overlapping symptoms, the concept of multisomatoform disorder (MSD) has been introduced as an encompassing concept. We hypothesize that a common neurohumoral profile is present in patients with MSD that is distinct from gender- and age-matched controls and thus provides insight into possible common underlying mechanisms.

Design

In 151 patients with MSD (138 females) and 149 matched controls (131 females), we determined ACE by the Childhood Trauma Questionnaire (CTQ) and chronic stress by the Trier Inventory for Chronic Stress (TICS). Furthermore, the serum levels of leptin, FSH, LH, cortisol, DHEA-S, and IGF-1 have been assessed.

Results

There were significant differences in the levels of leptin, FSH, IGF-1, and cortisol between patients and controls, mainly driven by female participants. Levels of leptin were significantly correlated with BMI in patients, in controls, and in the female subgroup. This correlation was exaggerated in female patients when compared to female controls. Both CTQ and TICS predicted MSD directly and indirectly through the levels of leptin.

Conclusion

There is evidence of a distinct neurohumoral profile in female patients with MSD when compared to matched healthy controls, similar to what has been demonstrated in other chronic pain states. The observed profile can be taken as possible evidence for a dysregulated response to chronic stress and metabolic balance as well as a state of hypocortisolism and HPA-axis dysfunction. ACE and chronic stress play a major role in the development of MSD and altered neurohumoral profile.

Secondary Adrenal Insufficiency and Growth Hormone Deficiency in Patients with Fibromyalgia

Purpose

Patients with fibromyalgia (FM) may demonstrate low cortisol concentrations during diagnostic evaluation. However, it remains unclear whether low cortisol reflects underlying pituitary dysfunction. We aimed to determine if a subset of patients with FM have concomitant secondary adrenal insufficiency (SAI) and growth hormone deficiency (GH).

Patients and Methods

This is a retrospective study of all patients with FM diagnosed with SAI based on abnormal insulin tolerance test (ITT) between June 2002 and August 2019. Patients were excluded if they had other reasons for SAI. Measurements include cortisol and GH during ITT in all patients, and peak cortisol during cosyntropin stimulation test in a subset of patients.

Results

We identified 22 patients (median age of 38 years (range 19-65), 18 (82%) women) diagnosed with secondary AI based on abnormal ITT (peak median cortisol level of 11 mcg/dL (range 5.4-17)). Concomitant GH deficiency was diagnosed in 19 (86%) patients. Cosyntropin stimulation test was performed in 14 (64%) patients and was normal in 11 (79%) (peak cortisol ≥18 mcg/dL). MRI pituitary imaging was performed in 20 patients and showed no significant pituitary pathology. All patients were started on physiologic glucocorticoid replacement, and 5 patients were started on GH replacement. Of the 13 patients with follow-up, 8 (62%) reported symptom improvement after starting treatment.

Conclusion

Patients with FM can have concurrent SAI and GH deficiency. Cosyntropin stimulation test should not be used to exclude SAI in patients with FM. Appropriate glucocorticoid and/or GH replacement may improve symptoms in some patients.

Theory: Treatments for Prolonged ICU Patients May Provide New Therapeutic Avenues for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

We here provide an overview of treatment trials for prolonged intensive care unit (ICU) patients and theorize about their relevance for potential treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Specifically, these treatment trials generally target: (a) the correction of suppressed endocrine axes, notably through a "reactivation" of the pituitary gland's pulsatile secretion of tropic hormones, or (b) the interruption of the "vicious circle" between inflammation, oxidative and nitrosative stress (O&NS), and low thyroid hormone function. There are significant parallels in the treatment trials for prolonged critical illness and ME/CFS; this is consistent with the hypothesis of an overlap in the mechanisms that prevent recovery in both conditions. Early successes in the simultaneous reactivation of pulsatile pituitary secretions in ICU patients-and the resulting positive metabolic effects-could indicate an avenue for treating ME/CFS. The therapeutic effects of thyroid hormones-including in mitigating O&NS and inflammation and in stimulating the adreno-cortical axis-also merit further studies. Collaborative research projects should further investigate the lessons from treatment trials for prolonged critical illness for solving ME/CFS.

Hypothesis: Mechanisms That Prevent Recovery in Prolonged ICU Patients Also Underlie Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Here the hypothesis is advanced that maladaptive mechanisms that prevent recovery in some intensive care unit (ICU) patients may also underlie Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Specifically, these mechanisms are: (a) suppression of the pituitary gland's pulsatile secretion of tropic hormones, and (b) a "vicious circle" between inflammation, oxidative and nitrosative stress (O&NS), and low thyroid hormone function. This hypothesis should be investigated through collaborative research projects.

The Search for Biomarkers in Fibromyalgia

Fibromyalgia is the most common of the central sensitivity syndromes affecting 2–5% of the adult population in the United States. This pain amplification syndrome has enormous societal impact as measured by work absenteeism, decreased work productivity, disability and injury compensation and over-utilization of healthcare resources. Multiple studies have shown that early diagnosis of this condition can improve patient outlook and redirect valuable healthcare resources towards more appropriate targeted therapy. Efforts have been made towards improving diagnostic accuracy through updated criteria. The search for biomarkers for diagnosis and verification of Fibromyalgia is an ongoing process. Inadequacies with current diagnostic criteria for this condition have fueled these efforts for identification of a reproducible marker that can verify this disease in a highly sensitive, specific and reproducible manner. This review focuses on areas of research for biomarkers in fibromyalgia and suggests that future efforts might benefit from approaches that utilize arrays of biomarkers to identify this disorder that presents with a diverse clinical phenotype.

Fibromyalgia: A Critical and Comprehensive Review

Fibromyalgia is a disorder that is part of a spectrum of syndromes that lack precise classification. It is often considered as part of the global overview of functional somatic syndromes that are otherwise medically unexplained or part of a somatization disorder. Patients with fibromyalgia share symptoms with other functional somatic problems, including issues of myalgias, arthralgias, fatigue and sleep disturbances. Indeed, there is often diagnostic and classification overlap for the case definitions of a variety of somatization disorders. Fibromyalgia, however, is a critically important syndrome for physicians and scientists to be aware of. Patients should be taken very seriously and provided optimal care. Although inflammatory, infectious, and autoimmune disorders have all been ascribed to be etiological events in the development of fibromyalgia, there is very little data to support such a thesis. Many of these disorders are associated with depression and anxiety and may even be part of what has been sometimes called affected spectrum disorders. There is no evidence that physical trauma, i.e., automobile accidents, is associated with the development or exacerbation of fibromyalgia. Treatment should be placed on education, patient support, physical therapy, nutrition, and exercise, including the use of drugs that are approved for the treatment of fibromyalgia. Treatment should not include opiates and patients should not become poly pharmacies in which the treatment itself can lead to significant morbidities. Patients with fibromyalgia are living and not dying of this disorder and positive outlooks and family support are key elements in the management of patients.

Glial Cell Line-Derived Neurotrophic Factor and Somatostatin Levels in Cerebrospinal Fluid of Patients Affected by Chronic Migraine and Fibromyalgia

The aim of the present study was to verify cerebrospinal fluid (CSF) levels of glial cell line-derived neurotrophic factor (GDNF) and somatostatin, both measured by sensitive immunoassay, in: 16 chronic migraine (CM) patients, 15 patients with an antecedent history of migraine without aura diagnosed as having probable chronic migraine (PCM) and probable analgesic-abuse headache (PAAH), 20 patients affected by primary fibromyalgia syndrome (PFMS), and 20 control subjects. Significantly lower levels of GDNF and somatostatin were found in the CSF of both CM and PCM + PAAH patients compared with controls (GDNF = P < 0.001, P < 0.002; somatostatin = P < 0.002, P < 0.0003), without significant difference between the two groups. PFMS patients, with and without analgesic abuse, also had significantly lower levels of both somatostatin and GDNF ( P < 0.0002, P < 0.001), which did not differ from those of CM and PCM + PAAH patients. A significant positive correlation emerged between CSF values of GDNF and those of somatostatin in CM ( r = 0.70, P < 0.02), PCM + PAAH ( r = 0.78, P < 0.004), and PFMS patients ( r = 0.68, P < 0.008). Based on experimental findings, it can be postulated that reduced CSF levels of GDNF and somatostatin in both CM and PCM + PAAH patients can contribute to sustained central sensitization underlying chronic head pain. The abuse of simple or combination analgesics does not seem to influence the biochemical changes investigated, which appear to be more strictly related to the chronic pain state, as demonstrated also for fibromyalgia.

Does aerobic exercise affect the hypothalamic-pituitary-adrenal hormonal response in patients with fibromyalgia syndrome?

[Purpose] The hypothalamic-pituitary-adrenal (HPA) axis in the etiopathogenesis of fibromyalgia is not clear. This study aimed to analyze the effects of a 6-week aerobic exercise program on the HPA axis in patients with fibromyalgia and to investigate the effects of this program on the disease symptoms, patients' fitness, disability, and quality of life. [Subjects and Methods] Fifty fibromyalgia patients were randomized to Group 1 (stretching and flexibility exercises at home for 6 weeks) and Group 2 (aerobic exercise three times a week and the same at-home exercises as Group 1 for 6 weeks). Serum levels of cortisol, adrenocorticotropic hormone, insulin-like growth factor-1, and growth hormone were analyzed at baseline and at the end of, and 1 hr after an exercise stress test. [Results] Group 2 showed better improvement in morning stiffness duration and pain. Growth hormone levels significantly increased after intervention and cortisol levels significantly decreased at time-time interaction in both groups. No significant differences in adrenocorticotropic hormone and insulin-like growth factor-1 were found. [Conclusion] The results of this study seem to support the hypothesis that there is a dysregulation of the HPA axis in patients with FM, and that a six-week exercise program can influence symptoms and affect the HPA axis hormones.

Knockdown of corticotropin-releasing factor in the central amygdala reverses persistent viscerosomatic hyperalgesia

Gastrointestinal nociception is exacerbated by chronic stress through an unknown mechanism. The amygdala is a key nucleus involved in the autonomic and neuroendocrine responses to stress. The goal of this study was to test the hypothesis that prolonged exposure of the central amygdala (CeA) to stress or the stress hormone cortisol (or corticosterone in rats) induces nociceptive behaviors mediated by corticotropin-releasing factor (CRF) within the CeA. We selectively knocked down CRF in the CeA via antisense oligodeoxynucleotides (ASO) in animals with targeted, stereotaxically placed corticosterone (CORT) micropellets or following repeated water avoidance stress (WAS). CRF expression in the CeA was analyzed concurrently with the assessment of visceral hypersensitivity to colonic distension and mechanical somatic withdrawal threshold. The responses were characterized at 7 or 28 days post implantation of the CORT micropellet or following 7 days of WAS. Exposure of the CeA to elevated CORT or WAS increased CRF expression and heightened visceral and somatic sensitivity. Infusion of CRF ASO into the CeA decreased CRF expression and attenuated visceral and somatic hypersensitivity in both models. Our study provides important evidence for a CRF-mediated mechanism specifically within the CeA that regulates stress-induced visceral and somatic nociception.

Knockdown of steroid receptors in the central nucleus of the amygdala induces heightened pain behaviors in the rat

Previously we demonstrated that exposure of the central nucleus of the amygdala (CeA) to elevated corticosterone (CORT) induces nociceptive behaviors that are reversed by glucocorticoid and/or mineralocorticoid (GR/MR) receptor antagonism. Here we test the hypothesis that in a cholesterol (CHOL)-implanted control rat, selective knockdown of GR/MR in the CeA would, via a corticotropin-releasing factor (CRF)-mediated mechanism, replicate the nociceptive behaviors produced by elevated amygdala CORT. Micropellets of CHOL or CORT were stereotaxically placed on the dorsal margin of the CeA. Cannulae were implanted into the CeA for the delivery of vehicle or oligodeoxynucleotide (ODN) of either antisense (ASO) or random sequences (RSO) targeting GR or MR. Visceromotor behavioral response quantified visceral sensitivity in response to colonic distension, while von Frey filaments assessed somatic sensitivity. Receptor expression was determined with qRT-PCR. In CHOL implanted controls, knockdown of GR in the CeA increased both colonic and somatic sensitivity, whereas selective knockdown of MR in the CeA induced colonic hypersensitivity without affecting somatic sensitivity. CRF expression in the CeA was increased in CHOL-implanted rats treated with GR or MR ASO and resembled the augmented CRF expression seen in the CORT-implanted rats. This is the first study to demonstrate that decreasing either GR or MR within the CeA is sufficient to induce visceral hypersensitivity whereas somatic hypersensitivity developed after only GR knockdown. The loss of either GR or MR was associated with an increased CRF expression, and may represent a common mechanism for the development of CeA-mediated nociceptive behaviors.

Brain-derived neurotrophic factor as a driving force behind neuroplasticity in neuropathic and central sensitization pain: a new therapeutic target?

INTRODUCTION

Central sensitization is a form of maladaptive neuroplasticity underlying many chronic pain disorders, including neuropathic pain, fibromyalgia, whiplash, headache, chronic pelvic pain syndrome and some forms of osteoarthritis, low back pain, epicondylitis, shoulder pain and cancer pain. Brain-derived neurotrophic factor (BDNF) is a driving force behind neuroplasticity, and it is therefore crucial for neural maintenance and repair. However, BDNF also contributes to sensitization of pain pathways, making it an interesting novel therapeutic target.

AREAS COVERED

An overview of BDNF's sensitizing capacity at every level of the pain pathways is presented, including the peripheral nociceptors, dorsal root ganglia, spinal dorsal horn neurons, and brain descending inhibitory and facilitatory pathways. This is followed by the presentation of several potential therapeutic options, ranging from indirect influencing of BDNF levels (using exercise therapy, anti-inflammatory drugs, melatonin, repetitive transcranial magnetic stimulation) to more specific targeting of BDNF's receptors and signaling pathways (blocking the proteinase-activated receptors 2-NK-κβ signaling pathway, administration of phencyclidine for antagonizing NMDA receptors, or blockade of the adenosine A2A receptor).

EXPERT OPINION

This section focuses on combining pharmacotherapy with multimodal rehabilitation for balancing the deleterious and therapeutic effects of BNDF treatment in chronic pain patients, as well as accounting for the complex and biopsychosocial nature of chronic pain.

Review of overlap between thermoregulation and pain modulation in fibromyalgia

Fibromyalgia (FM) syndrome is characterized by widespread pain that is exacerbated by cold and stress but relieved by warmth. We review the points along thermal and pain pathways where temperature may influence pain. We also present evidence addressing the possibility that brown adipose tissue activity is linked to the pain of FM given that cold initiates thermogenesis in brown adipose tissue through adrenergic activity, whereas warmth suspends thermogenesis. Although females have a higher incidence of FM and more resting thermogenesis, they are less able to recruit brown adipose tissue in response to chronic stress than males. In addition, conditions that are frequently comorbid with FM compromise brown adipose activity making it less responsive to sympathetic stimulation. This results in lower body temperatures, lower metabolic rates, and lower circulating cortisol/corticosterone in response to stress--characteristics of FM. In the periphery, sympathetic nerves to brown adipose also project to surrounding tissues, including tender points characterizing FM. As a result, the musculoskeletal hyperalgesia associated with conditions such as FM may result from referred pain in the adjacent muscle and skin.

Corticotropin-releasing factor-binding protein (CRF-BP) inhibits CRF- and urotensin-I-mediated activation of CRF receptor-1 and -2 in common carp

Corticotropin-releasing factor-binding protein (CRF-BP) is considered a key determinant for CRF receptor (CRF-R) activation by CRF and several related peptides. Earlier studies have shown that the CRF system is highly conserved in gene structures throughout evolution, yet little is known about the evolutionary conservation of its biological functions. Therefore, we address the functional properties of CRF-BP and CRF-Rs in a teleost fish (common carp; Cyprinus carpio L.). We report the finding of two similar, yet distinct, genes for both CRF-R1 and CRF-R2 in this species. The four receptors are differentially responsive to CRF, urotensin-I (UI), sauvagine, and urocortin-2 (Ucn-2) and -3 (Ucn-3) as shown by luciferase assays. In vitro, carp CRF-BP inhibits CRF- and UI-mediated activation of the newfound CRF-Rs, but its potency to do so varies between receptor and peptide ligand. This is the first paper to establish the functionality and physiological interplay between CRF-BP, CRF-Rs and CRF-family peptides in a teleostean species.

Meta-analysis and meta-regression of hypothalamic-pituitary-adrenal axis activity in functional somatic disorders

Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is the most investigated biological risk marker in functional somatic disorders (FSDs), such as chronic fatigue syndrome (CFS), fibromyalgia (FM), and irritable bowel syndrome (IBS). Our aim was to assess whether there is an association between basal hypocortisolism and FSD and to identify potential moderators of this association. Meta-analysis on 85 studies revealed that although basal cortisol levels were generally lower in FSD subjects compared to controls, this association did not reach statistical significance (SMD -0.07, 95% CI -0.17 to 0.04, p=0.241). However, when the three FSD were assessed separately, statistically significant basal hypocortisolism was observed in CFS subjects compared to controls (SMD -0.14, 95% CI -0.28 to 0.00, p=0.047), but not in FM or IBS. When all potential moderators were entered into a meta-regression analysis, only type of FSD and female gender were significant independent predictors of basal hypocortisolism. In conclusion, we did not find evidence to consider all three main FSD as hypocortisolemic disorders, as significant reduction in basal cortisol compared to healthy controls was only found in CFS and in females with FM, but not in IBS.

Objective measures of disordered sleep in fibromyalgia

OBJECTIVE

Patients with fibromyalgia syndrome (FM) complain of inadequate sleep, which could contribute to common symptoms including sleepiness, fatigue, or pain. However, measures that consistently and objectively distinguish FM patients remain elusive.

METHODS

Fifteen women with FM and 15 age- and gender-matched controls underwent 3 nights of polysomnography; Multiple Sleep Latency Tests to assess sleepiness; testing of auditory arousal thresholds during non-REM stage 2 and stage 4 sleep; overnight assessment of urinary free cortisol; and analysis of 24-hour heart rate variability.

RESULTS

On the second night of polysomnography, women with FM in comparison to controls showed more stage shifts (p = 0.04) but did not differ significantly on any other standard polysomnographic measure or on the Multiple Sleep Latency Tests. Alpha EEG power during deep non-REM sleep, alone or as a proportion of alpha power during remaining sleep stages, also failed to distinguish the groups, as did auditory arousal thresholds. Urinary free cortisol did not differ between FM and control subjects in a consistent manner. However, decreased short-term heart rate variability (HRV) and especially ratio-based HRV among FM subjects suggested diminished parasympathetic and increased sympathetic activity, respectively. Other HRV measures suggested decreased complexity of HRV among the FM subjects.

CONCLUSION

Standard measures of sleep, a gold-standard measure of sleepiness, quantified alpha-delta EEG power, auditory arousal thresholds, and urinary free cortisol largely failed to distinguish FM and control subjects. However, HRV analyses showed more promise, as they suggested both increased sympathetic activity and decreased complexity of autonomic nervous system function in FM.

Salivary cortisol and psychological mechanisms in patients with acute versus chronic low back pain

This study was designed to explore whether the basal adrenocortical activity is related with pain-related coping, nonverbal pain behavior, depressive mood, and fatigue in patients with acute and chronic nonspecific low back pain. 19 patients with acute low back pain (ALBP) and 24 with chronic low back pain (CLBP) participated in the study. The adrenocortical activity was assessed through the cortisol awakening response. All participants provided five saliva samples (0, 15, 30, 45, and 60min after waking) on two consecutive days off work. Pain-related coping [fear-avoidance coping (FAC) and endurance coping (EC)], nonverbal pain behavior (NPB), depressive mood, and fatigue were assessed through questionnaires. Among ALPB patients, EC was negatively associated with the cortisol release, whereas fatigue was positively associated with it. Among CLBP patients, FAC, NPB, depressive mood, and fatigue were negatively associated with the cortisol awakening response, whereas EC tended to be positively associated with it. The results indicate that pain-related coping strategies which are expected to be successful appear to lower the adrenocortical activity among ALBP patients, whereas affective distress may enhance the level of cortisol in this group. Among CLBP patients, long-term maladaptive coping strategies might contribute to hypocortisolism.

HPA axis reactivity and lymphocyte glucocorticoid sensitivity in fibromyalgia syndrome and chronic pelvic pain

OBJECTIVE

Chronic pelvic pain (CPP) and fibromyalgia syndrome (FMS) have been associated with hypothalamic-pituitary-adrenal (HPA) axis alterations, i.e., mild hypocortisolism and enhanced feedback sensitivity. We tested the hypothesis of reduced cortisol release in response to a psychosocial stressor and pharmacological stimulation. Furthermore, glucocorticoid (GC) sensitivity was evaluated.

METHODS

Plasma total and salivary-free cortisol concentrations were measured in response to a standardized social laboratory stressor, the Trier Social Stress Test, and to adrenocorticotropin (ACTH)(1-24) stimulation. In the Trier Social Stress Test, we additionally measured ACTH. GC sensitivity was measured by dexamethasone inhibition of lipopolysaccharide-induced interleukin-6 and tumor necrosis factor-alpha production in whole blood.

RESULTS

There were no HPA axis alterations in women with CPP (N = 18) in these tests. Patients with FMS (N = 17) showed lower total cortisol release in response to the social stressor and exogenous ACTH, but normal free cortisol and ACTH levels compared with controls (N = 24). GC sensitivity was similar in all groups.

CONCLUSIONS

Our results suggest normal HPA responses to stress and ACTH stimulation in patients with CPP but reduced adrenal reactivity in patients with FMS, namely in total cortisol release. Free cortisol on the other hand was unaltered, possibly reflecting an adaptation to reduced circulating total cortisol.

Fibromyalgia: a rheumatologic diagnosis?

Fibromyalgia (FM) is a medically unexplained or functional somatic syndrome (FSS). The two classification criteria are chronic widespread pain (CWP) and the finding of 11/18 tender points (TP). FM overlaps and co-occurs with other FSSs, and auxiliary symptoms that are not included in the criteria may be clues to other FSSs. About ten FSSs include chronic fatigue syndrome, myofascial pain syndromes and irritable bowel syndrome. TP do not reflect demonstrable pathology, and are locations where everyone is generally more tender. In FM they are more tender than normal due to lowered pain threshold. High TP counts are associated with the extent of distress or unspecific somatic symptoms in the absence of chronic pain. TP lack validity and should be excluded. CWP and distress are outside the domain of rheumatology, and abnormal mechanisms in FM relate to the central nervous system, as compared to "peripheral" mechanisms studied in rheumatology. FM should not be considered as a rheumatologic condition but rather as part of a broader spectre of FSSs. Patients with FSSs should be considered and treated together across medical specialities by general physicians in primary health care.

Growth Hormone Perturbations in Fibromyalgia: A Review

OBJECTIVE

Fibromyalgia (FM) is a syndrome characterized by chronic widespread pain, fatigue, disrupted sleep, depression, and physical deconditioning. In this article, we review the literature on the normal activity of the hypothalamic-pituitary-growth hormone-insulin-like growth factor-1 (HP-GH-IGF-1) axis and its perturbations in FM subjects.

METHODS

Studies included in this review were accessed through an English language search of Cochrane Collaboration Reviews. Keyword MeSH terms included "fibromyalgia," "growth hormone" (GH), or "insulin-like growth factor-1" (IGF-1).

RESULTS

Twenty-six studies enrolling 2006 subjects were reviewed. Overall, low levels of IGF-1 were found in a subgroup of subjects. Growth hormone stimulation tests often revealed a suboptimal response, which did not always correlate with IGF-1 levels. No consistent defects in pituitary function were found. Of the 3 randomized placebo controlled studies, only 9 months of daily injectable recombinant GH reduced FM symptoms and normalized IGF-1.

CONCLUSIONS

These studies suggest that pituitary function is normal in FM and that reported changes in the HP-GH-IGF-1 axis are most likely hypothalamic in origin. The therapeutic efficacy of supplemental GH therapy in FM requires further study before any solid recommendations can be made.

The hypothalamo-pituitary-adrenal axis in chronic fatigue syndrome and fibromyalgia syndrome

The hypothalamo-pituitary-adrenal (HPA) axis plays a major role in the regulation of responses to stress. Human stress-related disorders such as chronic fatigue syndrome (CFS), fibromyalgia syndrome (FMS), chronic pelvic pain and post-traumatic stress disorder are characterized by alterations in HPA axis activity. However, the role of the HPA axis alterations in these stress-related disorders is not clear. Most studies have shown that the HPA axis is underactive in the stress-related disorders, but contradictory results have also been reported, which may be due to the patients selected for the study, the methods used for the investigation of the HPA axis, the stage of the syndrome when the tests have been done and the interpretation of the results. There is no structural abnormality in the endocrine organs which comprise the HPA axis, thus it seems that hypocortisolemia found in the patients with stress-related disorder is functional. It may be also an adaptive response of the body to chronic stress. In this review, tests used in the assessment of HPA axis function and the HPA axis alterations found in CFS and FMS are discussed in detail.

Cerebrospinal fluid corticotropin-releasing factor concentration is associated with pain but not fatigue symptoms in patients with fibromyalgia

Previous studies have identified stress system dysregulation in fibromyalgia (FM) patients; such dysregulation may be involved in the generation and/or maintenance of pain and other symptoms. Corticotropin-releasing factor (CRF) is the principal known central nervous system mediator of the stress response; however, to date no studies have examined cerebrospinal fluid (CSF) CRF levels in patients with FM. The relationship between CSF CRF level, heart rate variability (HRV), and pain, fatigue, and depressive symptoms was examined in patients with FM. Among participants (n=26), CSF CRF levels were associated with sensory pain symptoms (r=0.574, p=0.003) and affective pain symptoms (r=0.497, p=0.011), but not fatigue symptoms. Increased HRV was also strongly associated with increased CSF CRF and FM pain. In multivariate analyses adjusting for age, sex, and depressive symptoms, the association between CSF CRF and sensory pain symptoms (t=2.54, p=0.027) persisted. Women with FM who reported a history of physical or sexual abuse had lower CSF CRF levels than women who did not report such a history. CSF CRF levels are associated with both pain symptoms and variation in autonomic function in FM. Differences in CSF CRF levels among women with and without a self-reported history of physical or sexual abuse suggest that subgroups of FM patients may exist with different neurobiological characteristics. Further studies are needed to better understand the nature of the association between CSF CRF and pain symptoms in FM.

Corticotropin releasing factor in urine—A possible biochemical marker of fibromyalgia

The purpose of this preliminary study was to evaluate the relationship between a possible biochemical marker of stress, 24-h urinary concentrations of Corticotropin Releasing Factor-Like Immunoreactivity (CRF-LI), and ratings of stress-related symptoms like depression and anxiety, as well as to evaluate pain and emotional reactions in patients with fibromyalgia (FM). Another purpose was to study the effects of massage and guided relaxation, with respect to change in the same variables. Urine sampling and ratings were performed before treatments, after and 1 month after completed treatments. Concentrations of CRF-LI was analysed with radioimmnoassay technique. For the assessment of depression, anxiety and pain the CPRS-A questionnaire was used and for rated pain and emotional reactions the NHP questionnaire was used. The 24-h urinary concentration of the CRF-LI was found to be related to depression, mood and inability to take initiative. After treatment the urinary CRF-LI concentrations and the rated levels of pain and emotional reactions were found to have decreased. In conclusion, the 24-h urinary CRF-LI concentration may be used as a biochemical marker of stress-related symptoms such as depression in patients with FM and possibly also other conditions characterized by chronic pain. Therapies such as massage and guided relaxation may be tried for the amelioration of pain and stress but further studies are required.

Mechanisms of Disease: pain in fibromyalgia syndrome

Despite extensive research, the pathogenesis of pain in fibromyalgia syndrome is incompletely understood. Fibromyalgia pain is consistently felt in deep tissues including ligaments, joints and muscles. Increasing evidence points towards these tissues as relevant contributors of nociceptive input that might either initiate or maintain central sensitization, or both. Persistent or intense nociception can lead to transcriptional and translational changes in the spinal cord and brain resulting in central sensitization and pain. This mechanism represents a hallmark of fibromyalgia and many other chronic pain syndromes, including irritable bowel syndrome, temporomandibular disorder, migraine, and low back pain. Importantly, after central sensitization has been established, only minimal nociceptive input is required for the maintenance of the chronic pain state. Other factors, including pain-related negative affect, have been shown to significantly contribute to clinical fibromyalgia pain. An improved understanding of the mechanisms that characterize central sensitization and clinical pain will provide new approaches for the prevention and treatment of fibromyalgia and other chronic pain syndromes.

Funktionsst�rung der hypothalamisch-hyphophys�r-adrenalen Achse bei Patienten mit akuten, chronischen und intervallartigen Schmerzsyndromen

INTRODUCTION

Complex disorders of the hypothalamic-pituitary-adrenal axis constitute phenomena whose etiopathogenetic significance is the subject of controversy. The frequent coincidence with depressive symptoms further complicates interpretation.

PATIENTS AND METHODS

Daily variations in cortisol levels were measured in 20 patients with acute pain, 27 with chronic pain in the lumbar musculoskeletal system, and 44 with episodic forms of headache to determine the daily average and then correlated with differentiated algesimetric data.

RESULTS

Patients with chronic and episodic pain had significantly higher scores on the McGill Pain Questionnaire and more affective items as an expression of depressive symptoms than patients with acute pain. The three groups did not however exhibit significant differences for the depression scale and list of "psychovegetative" disorders. In comparison to an age-matched pain-free control population (n=17), the average daily levels of cortisol were significantly higher in all three groups besides singularly elevated daily levels, but no correlations between the cortisol values and overall algesimetric data could be established. Chronic pain patients with high depression scores had significantly higher cortisol levels irrespective of pain intensity.

DISCUSSION

Pain experiences cause increased plasma cortisol levels with significant elevation of the daily average. Whereas in cases of acute pain, a direct but unspecific stress reaction not connected with the pain seems to be likely, the underlying cause in cases of chronic and episodic pain appears to be a complex and enduring activation of the hypothalamic-pituitary-adrenal axis, likewise independent from pain, probably associated with concomitant depressive symptoms and disruption of the circadian rhythm of release controlled by the hypothalamus.

Momentary relationship between cortisol secretion and symptoms in patients with fibromyalgia

OBJECTIVE

To compare the momentary association between salivary cortisol levels and pain, fatigue, and stress symptoms in patients with fibromyalgia (FM), and to compare diurnal cycles of cortisol secretion in patients with FM and healthy control subjects in a naturalistic environment.

METHODS

Twenty-eight patients with FM and 27 healthy control subjects completed assessments on salivary cortisol levels and pain, fatigue, and stress symptoms, 5 times a day for 2 consecutive days, while engaging in usual daily activities. Only those participants who adhered to the protocol (assessed via activity monitor) were included in the final analyses.

RESULTS

Twenty FM patients and 16 healthy control subjects adhered to the protocol. There were no significant differences in cortisol levels or diurnal cortisol variation between FM patients and healthy controls. Among women with FM, a strong relationship between cortisol level and current pain symptoms was observed at the waking time point (t = 3.35, P = 0.008) and 1 hour after waking (t = 2.97, P = 0.011), but not at the later 3 time points. This association was not due to differences in age, number of symptoms of depression, or self-reported history of physical or sexual abuse. Cortisol levels alone explained 38% and 14% of the variation in pain at the waking and 1 hour time points, respectively. No relationship was observed between cortisol level and fatigue or stress symptoms at any of the 5 time points.

CONCLUSION

Among women with FM, pain symptoms early in the day are associated with variations in function of the hypothalamic-pituitary-adrenal axis.

The neuroendocrinology of chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a common and disabling problem; although most likely of biopsychosocial origin, the nature of the pathophysiological components remains unclear. There has been a wealth of interest in the endocrinology of this condition, which will be reviewed in this article. Most studied has been the hypothalamic-pituitary-adrenal (HPA) axis; although the quality of many studies is poor, the overall balance of evidence points to reduced cortisol output in at least some patients, with some evidence that this is linked to symptom production or persistence. There is evidence for heightened negative feedback and glucocorticoid receptor function and for impaired ACTH and cortisol responses to a variety of challenges. However, there is no evidence for a specific or uniform dysfunction of the HPA axis. Given the many factors that may impinge on the HPA axis in CFS, such as inactivity, sleep disturbance, psychiatric comorbidity, medication, and ongoing stress, it seems likely that HPA axis disturbance is heterogeneous and of multifactorial etiology in CFS. Studies assessing GH, dehydroepiandrostenedione and its sulfate, melatonin, leptin, and neuroendocrine-monoamine interactions are also reviewed. There is some evidence from these studies to suggest alterations of dehydroepiandrostenedione sulfate function and abnormal serotonin function in CFS, but whether these changes are of functional importance remains unclear. To obtain a clearer assessment of the etiological and pathophysiological relevance of endocrine changes in CFS, it is suggested that more prospective cohort studies be undertaken in groups at high risk for CFS, that patients with CFS are followed up into recovery, and that multidimensional assessments are undertaken to unravel the influence of the various confounding factors on the observed endocrine changes in CFS.