Sleep, neuroimmune and neuroendocrine functions in fibromyalgia and chronic fatigue syndrome

Molecular links between endocrine, nervous and immune system during chronic stress

INTRODUCTION

The stress response is different in various individuals, however, the mechanisms that could explain these distinct effects are not well known and the molecular correlates have been considered one at the time. Particular harmful conditions occur if the subject, instead to cope the stressful events, succumb to them, in this case, a cascade reaction happens that through different signaling causes a specific reaction named "sickness behaviour." The aim of this article is to review the complex relations among important molecules belonging to Central nervous system (CNS), immune system (IS), and endocrine system (ES) during the chronic stress response.

METHODS

After having verified the state of art concerning the function of cortisol, norepinephrine (NE), interleukin (IL)-1β and melatonin, we describe as they work together.

RESULTS

We propose a speculative hypothesis concerning the complex interplay of these signaling molecules during chronic stress, highlighting the role of IL-1β as main biomarker of this effects, indeed, during chronic stress its increment transforms this inflammatory signal into a nervous signal (NE), in turn, this uses the ES (melatonin and cortisol) to counterbalance again IL-1β. During cortisol resistance, a vicious loop occurs that increments all mediators, unbalancing IS, ES, and CNS networks. This IL-1β increase would occur above all when the individual succumbs to stressful events, showing the Sickness Behaviour Symptoms. IL-1β might, through melatonin and vice versa, determine sleep disorders too.

CONCLUSION

The molecular links here outlined could explain how stress plays a role in etiopathogenesis of several diseases through this complex interplay.

Sleep fragmentation exacerbates mechanical hypersensitivity and alters subsequent sleep-wake behavior in a mouse model of musculoskeletal sensitization

STUDY OBJECTIVES

Sleep deprivation, or sleep disruption, enhances pain in human subjects. Chronic musculoskeletal pain is prevalent in our society, and constitutes a tremendous public health burden. Although preclinical models of neuropathic and inflammatory pain demonstrate effects on sleep, few studies focus on musculoskeletal pain. We reported elsewhere in this issue of SLEEP that musculoskeletal sensitization alters sleep of mice. In this study we hypothesize that sleep fragmentation during the development of musculoskeletal sensitization will exacerbate subsequent pain responses and alter sleep-wake behavior of mice.

DESIGN

This is a preclinical study using C57BL/6J mice to determine the effect on behavioral outcomes of sleep fragmentation combined with musculoskeletal sensitization.

METHODS

Musculoskeletal sensitization, a model of chronic muscle pain, was induced using two unilateral injections of acidified saline (pH 4.0) into the gastrocnemius muscle, spaced 5 days apart. Musculoskeletal sensitization manifests as mechanical hypersensitivity determined by von Frey filament testing at the hindpaws. Sleep fragmentation took place during the consecutive 12-h light periods of the 5 days between intramuscular injections. Electroencephalogram (EEG) and body temperature were recorded from some mice at baseline and for 3 weeks after musculoskeletal sensitization. Mechanical hypersensitivity was determined at preinjection baseline and on days 1, 3, 7, 14, and 21 after sensitization. Two additional experiments were conducted to determine the independent effects of sleep fragmentation or musculoskeletal sensitization on mechanical hypersensitivity.

RESULTS

Five days of sleep fragmentation alone did not induce mechanical hypersensitivity, whereas sleep fragmentation combined with musculoskeletal sensitization resulted in prolonged and exacerbated mechanical hypersensitivity. Sleep fragmentation combined with musculoskeletal sensitization had an effect on subsequent sleep of mice as demonstrated by increased numbers of sleep-wake state transitions during the light and dark periods; changes in nonrapid eye movement (NREM) sleep, rapid eye movement sleep, and wakefulness; and altered delta power during NREM sleep. These effects persisted for at least 3 weeks postsensitization.

CONCLUSIONS

Our data demonstrate that sleep fragmentation combined with musculoskeletal sensitization exacerbates the physiological and behavioral responses of mice to musculoskeletal sensitization, including mechanical hypersensitivity and sleep-wake behavior. These data contribute to increasing literature demonstrating bidirectional relationships between sleep and pain. The prevalence and incidence of insufficient sleep and pathologies characterized by chronic musculoskeletal pain are increasing in the United States. These demographic data underscore the need for research focused on insufficient sleep and chronic pain so that the quality of life for the millions of individuals with these conditions may be improved.

Attitudes to knee osteoarthritis and total knee replacement in Arab women: a qualitative study

Background

Total Knee Arthroplasty (TKA) is offered to patients with knee osteoarthritis (OA) in the oil-rich countries in the Gulf region without adequate understanding of their perceptions, preferences or pain experiences. This study aimed to explore the pain experience and mobility limitation as well as the patient’s decision making process to undertake TKA among women with knee pain in the waiting list for surgery.

Methods

Five focus group discussions were conducted comprised of 39 women with severe knee OA from the waiting list for TKA in the only orthopaedic hospital in Kuwait. Discussions were recorded, transcribed and coded for themes to identify the factors considered to be important in decision-making for TKA.

Results

Experiencing knee pain was central to daily living and affected patients and their families. Mobility limitation was shaped by a strong sense of expected obligation to take care of the family. Two major sources of TKA delay were identified; one was due to late clinical advice to undergo TKA which was the result of receiving several consultations from different clinicians each of whom tried the medical management for OA. The second delay occurred after the clinical advice for TKA and was mainly due to ambivalence of patients because of fear of the operation and the lack of information about TKA that resulted in unclear expectations of the surgery.

Conclusions

Both verbal and written information about TKA should be provided as part of preoperative rehabilitation. This is critical to improve doctor-patient interactions and facilitate informed decision about the procedure and thus achieve patient-centered healthcare.

Linking disease symptoms and subtypes with personalized systems-based phenotypes: a proof of concept study

A dynamic systems model was used to generate parameters describing a phenotype of Hypothalamic-Pituitary-Adrenal (HPA) behavior in a sample of 36 patients with chronic fatigue syndrome (CFS) and/or fibromyalgia (FM) and 36 case-matched healthy controls. Altered neuroendocrine function, particularly in relation to somatic symptoms and poor sleep quality, may contribute to the pathophysiology of these disorders. Blood plasma was assayed for cortisol and ACTH every 10 min for 24h. The dynamic model was specified with an ordinary differential equation using three parameters: (1) ACTH-adrenal signaling, (2) inhibitory feedback, and (3) non-ACTH influences. The model was "personalized" by estimating an individualized set of parameters from each participant's data. Day and nighttime parameters were assessed separately. Two nocturnal parameters (ACTH-adrenal signaling and inhibitory feedback) significantly differentiated the two patient subgroups ("fatigue-predominant" patients with CFS only versus "pain-predominant" patients with FM and comorbid chronic fatigue) from controls (all p's<.05), whereas daytime parameters and diurnal/nocturnal slopes did not. The same nocturnal parameters were significantly associated with somatic symptoms among patients (p's<.05). There was a significantly different pattern of association between nocturnal non-ACTH influences and sleep quality among patients versus controls (p<.05). Although speculative, the finding that patient somatic symptoms decreased when more cortisol was produced per unit ACTH, is consistent with cortisol's anti-inflammatory and sleep-modulatory effects. Patients' HPA systems may compensate by promoting more rapid or sustained cortisol production. Mapping "behavioral phenotypes" of stress-arousal systems onto symptom clusters may help disentangle the pathophysiology of complex disorders with frequent comorbidity.

Burden of illness and treatment patterns for patients with fibromyalgia

OBJECTIVE

  This study was designed to describe burden of illness and treatment patterns, and to examine the patient, physician, and care factors associated with the treatment choices of individuals receiving new prescriptions for fibromyalgia (FM).

DESIGN

  This is a baseline assessment of the Real-World Examination of Fibromyalgia: Longitudinal Evaluation of Costs and Treatments (REFLECTIONS), a prospective observational study. Baseline data (including a physician survey, a patient visit form, and computer-assisted telephone interviews) were collected from July 2008 through May 2010 in 58 care settings in the United States, including Puerto Rico.

RESULTS

  Patients (N = 1,700) were mostly female (94.6%) and white (82.9%). Mean age was 50.4 years and mean duration of illness was 5.6 years. Mean Fibromyalgia Impact Questionnaire total score was 54.4 (range 0-80), and Brief Pain Inventory average pain severity level was 5.5 (range 0-10). Patients reported high annual health care use and numerous work limitations related to FM. Patients were taking 182 unique types of medications prescribed for FM, including duloxetine (26.8%), nonsteroidal anti-inflammatory drugs (26.6%), pregabalin (24.5%), opioids (24.2%), tramadol (15.3%), benzodiazepines (15.2%), cyclobenzaprine (12.9%), milnacipran (8.9%), and others. Most patients took more than one medication concurrently (77.8%). Type of current medications used was most strongly associated with medication history and physician specialty.

CONCLUSIONS

  Burden of illness was high for patients with FM, and treatment patterns were highly variable. Importantly, the treatments with the most evidence to support their use were not always the most frequently chosen.

Humoral sleep regulation; interleukin-1 and tumor necrosis factor

Two substances, the cytokines interleukin-1 beta (IL1β) and tumor necrosis factor alpha (TNFα), known for their many physiological roles, for example, cognition, synaptic plasticity, and immune function, are also well characterized in their actions of sleep regulation. These substances promote non-rapid eye movement sleep and can induce symptoms associated with sleep loss such as sleepiness, fatigue, and poor cognition. IL1β and TNFα are released from glia in response to extracellular ATP. They bind to their receptors on neurons resulting in neuromodulator and neurotransmitter receptor up/downregulation (e.g., adenosine and glutamate receptors) leading to altered neuronal excitability and function, that is, a state change in the local network. Synchronization of state between local networks leads to emergent whole brain oscillations, such as sleep/wake cycles.

Sleep-wake behavior in chronic fatigue syndrome

STUDY OBJECTIVES

Disturbances of the internal biological clock manifest as fatigue, poor concentration, and sleep disturbances-symptoms reminiscent of chronic fatigue syndrome (CFS) and suggestive of a role for circadian rhythm disturbance in CFS. We examined circadian patterns of activity, sleep, and cortisol secretion in patients with CFS.

DESIGN

Case-control study, 5-day behavioral observation.

SETTING

Natural setting/home environment

PARTICIPANTS

15 patients with CFS and 15 healthy subjects of similar age, sex, body mass index (BMI), and activity levels.

INTERVENTIONS

N/A.

MEASUREMENTS

Self-report questionnaires were used to obtain medical history and demographic information and to assess health behaviors, somatic and psychological symptoms, and sleep quality. An actiwatch accelerometer recorded activity and sleep patterns over 5 days with concurrent activity and symptom logs. Diurnal salivary cortisol secretion was measured. Additionally, overnight heart rate monitoring and pain sensitivity assessment was undertaken.

RESULTS

Ratings of symptoms, disability, sleep disturbance, and pain sensitivity were greater in patients with CFS. No between-group differences were found in the pattern or amount of sleep, activity, or cortisol secretion. Afternoon activity levels significantly increased evening fatigue in patients but not control subjects. Low nocturnal heart rate variability was identified as a biological correlate of unrefreshing sleep.

CONCLUSIONS

We found no evidence of circadian rhythm disturbance in CFS. However, the role of autonomic activity in the experience of unrefreshing sleep warrants further assessment. The activity symptom-relationship modelled here is of clinical significance in the approach to activity and symptom management in the treatment of CFS.

Neonatal lipopolysaccharide exposure alters central cytokine responses to stress in adulthood in Wistar rats

"Perinatal programming" is a phenomenon describing how early life environmental conditions can produce long-term physiological alterations that either enhance or inhibit adaptive functioning. Previously, we have demonstrated that neonatal exposure to lipopolysaccharide (LPS) predisposes to anxiety-like behaviour in later life, which was associated with changes to the neuroendocrine response to stress. Given the known interactions between the neuroendocrine and neuroimmune systems, here we investigated whether neonatal exposure to a bacterial mimetic alters neuroimmune responses to acute stress in adulthood. Male and female Wistar rats were administered LPS (0.05 mg/kg, i.p.), or saline vehicle (equivolume) on days 3 and 5 post-partum. One group of rats was euthanised following early life treatment to assess immediate hypothalamic-pituitary-adrenal axis and central cytokine responses to treatment. A second group was assessed in adulthood (85 days) following exposure to either a "stress" (30-min restraint) or "no stress" condition. Blood was collected from all rats at baseline, 30, 60 and 90 min after "stress", "no stress" treatment to assess peripheral corticosterone responses, and brains were collected 180 min following baseline to assess hippocampal content of interleukin-1β (IL-1β), tumour necrosis factor-α (TNFα) and IL-6 protein. Radioimmunoassay revealed that neonatal LPS treatment resulted in a prolonged corticosterone response to stress in adulthood compared to controls (p < 0.05). Enzyme-linked-immunosorbent assays revealed no group differences in hippocampal IL-6 content. However, brain IL-1β and TNFα protein concentrations were significantly greater in rats neonatally exposed to LPS and then exposed to stress in adulthood when compared to all other groups (p < 0.05). These findings suggest that early life bacterial toxin exposure results in a prolonged neuroendocrine response to acute stress in adulthood, which may be a consequence of increased release of IL-1β and TNFα in the brain.

Night pain in hip and knee osteoarthritis: a focus group study

OBJECTIVE

To explore the experience of night pain in people with hip or knee osteoarthritis (OA).

METHODS

Twenty-eight focus groups were conducted in 6 centers in 4 countries, with a total of 130 men and women with hip or knee OA. Two focus groups were excluded from the analysis, leaving 26 groups comprising 123 participants. Sampling was performed to ensure approximately equal representation of individuals with mild, moderate, and severe pain, hip OA, and knee OA. Format and methodology were standardized across centers, and participants described and discussed their experience of night pain. The focus groups were audio-recorded and transcribed. Data were analyzed by identifying emergent codes that were grouped and compared, resulting in the identification of key themes.

RESULTS

The majority of participants (81%) experienced night pain; the remaining 19%, who reported no night pain, were from the moderate or severe pain focus groups. Similar night pain experiences were expressed by the hip and knee OA participants. Night pain was also present regardless of the stage of OA, but severity increased as the disease progressed. Night pain was variable and intermittent. Three key themes were identified: prediction of night pain, sleep disturbance, and adaptations and treatment regimens.

CONCLUSION

Due to its variability and complexity, the assessment of night pain should take into account the importance of the patient narrative. Also, night pain may not be a distinct marker of disease severity, and this may have implications for its use as a priority indicator for total joint replacement.

The role of cytokines in sleep regulation

Interleukin-1 beta (IL1) and tumor necrosis factor alpha (TNF) promote non-rapid eye movement sleep under physiological and inflammatory conditions. Additional cytokines are also likely involved but evidence is insufficient to conclude that they are sleep regulatory substances. Many of the symptoms induced by sleep loss, e.g. sleepiness, fatigue, poor cognition, enhanced sensitivity to pain, can be elicited by injection of exogenous IL1 or TNF. We propose that ATP, released during neurotransmission, acting via purine P2 receptors on glia releases IL1 and TNF. This mechanism may provide the means by which the brain keeps track of prior usage history. IL1 and TNF in turn act on neurons to change their intrinsic properties and thereby change input-output properties (i.e. state shift) of the local network involved. Direct evidence indicates that cortical columns oscillate between states, one of which shares properties with organism sleep. We conclude that sleep is a local use-dependent process influenced by cytokines and their effector molecules such as nitric oxide, prostaglandins and adenosine.

Neuroimmune interaction in inflammatory diseases

The inflammatory response is modulated through interactions among the nervous, endocrine, and immune systems. Intercommunication between immune cells and the autonomic nervous system is a growing area of interest. Spatial and temporal information about inflammatory processes is relayed to the central nervous system (CNS) where neuroimmune modulation serves to control the extent and intensity of the inflammation. Over the past few decades, research has revealed various routes by which the nervous system and the immune system communicate. The CNS regulates the immune system via hormonal and neuronal pathways, including the sympathetic and parasympathetic nerves. The immune system signals the CNS through cytokines that act both centrally and peripherally. This review aims to introduce the concept of neuroimmune interaction and discuss its potential clinical application, in an attempt to broaden the awareness of this rapidly evolving area and open up new avenues that may aid in the treatment of inflammatory diseases.

Understanding the pain experience in hip and knee osteoarthritis--an OARSI/OMERACT initiative

OBJECTIVE

To examine the pain experience of people with hip or knee osteoarthritis (OA), particularly changes over time and most distressing features.

METHOD

Focus groups in individuals aged 40+ years with painful hip or knee OA obtained detailed descriptions of OA pain from early to late disease. A modified Patient Generated Index (PGI) was used to assess the features of OA pain that participants found most distressing. Content analysis was performed to examine response patterns; descriptive statistics were used to summarize PGI responses.

RESULTS

Mean age of the 143 participants (52 hip OA; 91 knee OA) was 69.5 years (47-92 years); 60.8% were female and 93.7% Caucasian. Participants described two distinct types of pain - a dull, aching pain, which became more constant over time, punctuated increasingly with short episodes of a more intense, often unpredictable, emotionally draining pain. The latter, but not the former, resulted in significant avoidance of social and recreational activities. From PGI responses, distressing pain features were: the pain itself (particularly intense and unpredictable pain) and the pain's impact on mobility, mood and sleep.

CONCLUSIONS

Two distinct pain types were identified. Intermittent intense pain, particularly when unpredictable, had the greatest impact on quality of life.

Fibromyalgia: nosography and therapeutic perspectives

Fibromyalgia (FM) is an important cause of morbidity and health expenditure. Severe widespread extra-articular chronic pain, along with nonrestorative sleep, dominates the clinical syndrome. The pathogenesis of FM remains unclear. While dysfunction in serotoninergic neurotransmission is believed to play an important role, several neurologic and immuno-endocrine mechanisms may also be relevant. A theory is advanced based on an inherited imbalance in neuro-vegetative systems resulting from increased sympathetic tone because of a metabolic deficiency in the serotoninergic system that, when exposed to a precipitating event, leads to the development of the clinical manifestations of FM. The importance of both nonpharmacological treatments and multimodal medication management is stressed.

Physiology and neurobiology of stress and adaptation: central role of the brain

The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging. Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms. Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load"). Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis"). The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids. Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course. Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging. The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses. As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience.

In search of pharmacoeconomic evaluations for fibromyalgia treatments: a review

Fibromyalgia is characterised by chronic widespread pain of unknown aetiology and affects approximately 2% of the population. It can cause significant patient disability, sizeable economic costs, complex management decisions and controversy for healthcare providers. In lieu of uniformly approved treatments for fibromyalgia, patients may try multiple pharmacological and non-pharmacological therapies with questionable efficacy. The literature lacks pharmacoeconomic studies that balance the cost and benefit of interventions. In the absence of this work, cost outcomes are reviewed in this paper. Due to inconclusive results, further study is needed on fibromyalgia treatment cost-effectiveness. These analyses could provide useful information for policy and evidence-based practice guidelines toward optimal disease management. Medical professionals should be a driving force in understanding the clinical and economic challenges of fibromyalgia.

Influence of melatonin on fatigue severity in patients with chronic fatigue syndrome and late melatonin secretion

The effect of melatonin, a chronobiotic drug, was explored in 29 patients with chronic fatigue syndrome (CFS) and Dim Light Melatonin onset (DLMO) later than 21.30 hours, reflective of delayed circadian rhythmicity. The patients took 5 mg of melatonin orally, 5 h before DLMO during 3 months. Their responses to the checklist individual strength (CIS), a reliable questionnaire measuring the severity of personally experienced fatigue, were assessed twice with a 6-week interval immediately before the treatment and once after 3 months treatment. In the pre-treatment period the fatigue sub-score improved significantly. After treatment, the total CIS score and the sub-scores for fatigue, concentration, motivation and activity improved significantly. The sub-score fatigue normalized in two of the 29 patients in the pre-treatment period and in eight of 27 patients during treatment. This change was significant. In the patients with DLMO later than 22.00 hours (n=21) the total CIS score and the sub-scores for fatigue, concentration and activity improved significantly more than in the patients (n=8) with DLMO earlier than 22.00 hours. Melatonin may be an effective treatment for patients with CFS and late DLMO, especially in those with DLMO later than 22.00 hours.

Pain, psychological variables, sleep quality, and natural killer cell activity in midlife women with and without fibromyalgia

In women with fibromyalgia (FM), central nervous system (CNS) dysfunction in pain, mood, and sleep processes could be associated with changes in immune system indicators. The primary purpose of this study was to compare pain, psychological variables, subjective and objective sleep quality, lymphocyte phenotypes and activation markers, and natural killer activity (NKA) in midlife women with and without FM. A secondary purpose was to explore relationships among these variables in a step-wise regression. Subjects had pain pressure tender points assessed, completed a psychiatric interview and questionnaires (Beck Depression Inventory, SCL-90, Profile of Mood States, subjective sleep), and underwent polysomnograhic assessment for two consecutive nights. Lymphocyte phenotypes, activation markers, and NKA were assessed from blood drawn the morning after sleep laboratory night 2. Compared to controls, women with FM had lower pain thresholds, more psychological distress, higher depression scores, and reduced subjective and objective sleep quality. They also had fewer NK cells (p <.009) and more NK cells that expressed the IL-2 receptor (p <.04), but these differences were not statistically significant after correction for multiple comparisons. NKA was not statistically significantly lower in the women with FM compared to controls. In a multiple regression of age, tender point threshold, depression, psychological distress, and sleep efficiency, only the effect of group was significant (F = 5.479, p <.03) on NKA. In conclusion, we found little evidence to support the hypothesis that pain, mood, and sleep symptoms are associated with changes in the enumeration of peripheral lymphocytes or function in FM.

Interacting mediators of allostasis and allostatic load: towards an understanding of resilience in aging

Individual differences in the aging process can be conceptualized as an accumulation of wear and tear of daily experiences and major life stressors that interact with the genetic constitution and predisposing early life experiences. The neuroendocrine system, autonomic nervous system, and immune system are mediators of adaptation to challenges of daily life, referred to as allostasis, meaning "maintaining stability through change." Physiological mediators such as adrenalin from the adrenal medulla, glucocorticoids from the adrenal cortex, and cytokines from cells of the immune system act upon receptors in various tissues and organs to produce effects that are adaptive in the short run but can be damaging if the mediators are not shut off when no longer needed. When release of the mediators is not efficiently terminated, their effects on target cells are prolonged, leading to other consequences that may include receptor desensitization and tissue damage. This process has been named "allostatic load," and it refers to the price the tissue or organ pays for an overactive or inefficiently managed allostatic response. Therefore, allostatic load refers to the "cost" of adaptation. This article discusses the mediators of allostasis and their contributions to allostatic load as well as their role in resilience of the aging organism to stressful experiences.

Improved sleep may reduce arthritis pain

Studies indicate that pain interferes with sleep and, in turn, sleep disturbances increase pain. Statistics show that up to 60% of those with arthritis experience pain during the night. But despite these findings, sleep is not generally addressed as a major treatment concern among this population. This article reviews the relationship between pain and sleep; sleep issues as they relate to 3 common types of arthritis--osteoarthritis, rheumatoid arthritis, and fibromyalgia; and holistic approaches that may be used by the patient in the self-management of pain and sleep.

Chronic fatigue syndrome: probable pathogenesis and possible treatments

Chronic fatigue syndrome (CFS) belongs in the medically unexplained illnesses. It affects approximately 0.2-0.7% of the population in Western countries. It is characterised by unexplained fatigue, lasting 6 months or more, impairment of neurocognitive functions and quality of sleep, and of somatic symptoms, such as recurrent sore throat, muscle aches, arthralgias, headache and postexertional malaise. No link between infections and CFS has been clearly established but the immune system is activated, there are aberrations in several hypothalamic-pituitary axes and involvement of other parts of the central nervous system. No specific treatment has been found. Cognitive behavioural therapy is established to be of value to improve quality of life. More effective treatment should result, as advances in biomedical as well as psychological research continue.

Predictors of somatic symptoms in depressive disorder

We explored the relative contribution of potential psychological predictors of somatic symptoms in outpatients with major depressive disorder, including; 1) severity of depression; 2) general anxiety; 3) hypochondriacal worry; 4) somatosensory amplification; and, 5) alexithymia by sampling 100 consecutive outpatients with DSM-IV diagnoses of major depressive disorder attending the psychiatry clinics of general hospitals in Turkey. The subjects were rated by clinicians on depressive symptomatology (Hamilton Depression Rating Scale), and anxiety (Hamilton Anxiety Scale), and completed self-report measures of Hypochondriacal worry (7-item version of the Whiteley Index), the Somatosensory Amplification Scale, and the Toronto Alexithymia Scale. Multivariate models tested the independent contribution of each of the scales to the level of somatic symptoms as measured by a modified version of the SCL-90 somatization scale. At the bivariate level, somatic symptoms were associated with female gender and lower educational level, as well as the Hamilton Depression and Anxiety scales, the Whitely Index, and the Somatosensory Amplification and Alexithymia scales. In multiple regression models incorporating all variables, female gender and higher scores on the anxiety, somatosensory amplification and alexithymia scales all made independent contributions to the level of somatic symptoms and accounted for 54% of the variance. Therefore, somatic symptoms in depression are related to concomitant anxiety, tendency to amplify somatic distress, and difficulty identifying and communicating emotional distress. However, these factors do not account for the tendency for women to report more somatic symptoms.

Management of sleep disorders in fibromyalgia

In summary, the treatment of patients with FM requires a proper assessment of the reason for the unrefreshing sleep, which is an important component of the FM syndrome. Sleep laboratory investigations provides a suitable rationale for management where a specific primary sleep disorder is determined. Nonspecific treatments include various behavioral approaches to improve sleep hygiene, fitness, and regular proper nutrition that serve to regularize disturbances in circadian sleep-wake rhythms. As yet, no medication is known to improve the EEG sleep arousal disorders that include phasic (alpha-delta), tonic alpha non-REM sleep disorders, or the periodic K alpha cycling alternating pattern disorder. Traditional hypnotic agents, while helpful in initiating and maintaining sleep and reducing daytime tiredness, do not provide restorative sleep or reduce pain. Tricyclic drugs, such as amitriptyline and cyclobenzaprine, may provide long term benefit for improving sleep but may not have a continuing benefit beyond one month for reducing pain. The use of a biologic agent that facilitates sleep-related neuroendocrine functions, for example growth hormone, is reported to improve symptoms but the need for injection and high cost restrict its use. No systematic studies have been reported on the use of remedial measures for the management of PLMS/restless legs syndrome and sleep apnea that occur in some patients with FM.

Fibromyalgia Syndrome, Idiopathic Widespread Persistent Pain or Syndrome of Myalgic Encephalomyelopathy (SME): What Is Its Nature?

CONTEXT

Fibromyalgia is a disorder that is appearing more and more in the clinical practice but is poorly understood.

OBJECTIVE

This paper attempts to look at all available and reliable data on these conditions and will outline current, scientifically sound understanding of these disorders, treatment modalities and future directions for research. It also attempts to analyze the social and cultural implications.

DATA SOURCES/STUDY SELECTION

Various terms used to describe these syndromes are fibromyalgia (FMS), and myalgic encephalomyelitis (ME). PubMed search was performed. Pertinent articles published in past 25 years and The National Academy of Sciences colloquium on Neurobiology of Pain was also reviewed. In addition, news-articles in the lay press as well as the Internet were monitored for material posted by sufferers of these disorders.

DATA EXTRACTION

Studies were reviewed for clinical presentations, history of these disorders, comorbid conditions, etiology, biochemical and microbiologic abnormalities, abnormalities found on neuroimaging and functional neurophysiologic techniques. In addition patient postings on the Internet and articles appearing in lay press were reviewed and social implications are discussed.

DATA SYNTHESIS

Upon analysis of these materials the review was organized based on the quality of data and it's contextual scientific, cultural and political meaning for this disorder. This review appears to be pointing towards an entirely new paradigm in pain disorders; therefore, a hypothesis and future direction of research is repeatedly suggested.

CONCLUSION

This study proposes an entirely new paradigm in these disorders based on scientific and cultural data.

Cytokine and other immunologic markers in chronic fatigue syndrome and their relation to neuropsychological factors

The literature is reviewed and data are presented that relate to a model we have developed to account for the perpetuation of the perplexing disorder currently termed chronic fatigue syndrome (CFS). In patients with CFS there is chronic lymphocyte overactivation with cytokine abnormalities that include perturbations in plasma levels of proinflammatory cytokines and decrease in the ratio of Type 1 to Type 2 cytokines produced by lymphocytes in vitro following mitogen stimulation. The initiation of the syndrome is frequently sudden and often follows an acute viral illness. Our model for the subsequent chronicity of this disorder holds that the interaction of psychological factors (distress associated with either CFS-related symptoms or other stressful life events) and the immunologic dysfunction contribute to (a) CFS-related physical symptoms (e.g., perception of fatigue and cognitive difficulties, fever, muscle and joint pain) and increases in illness burden and (b) impaired immune surveillance associated with cytotoxic lymphocytes with resulting activation of latent herpes viruses.

Sleep and pain

Noxious stimuli and painful disorders interfere with sleep, but disturbances in sleep also contribute to the experience of pain.Chronic paroxysmal hemicrania and possibly cluster headaches are related to REM sleep. Whereas headache is associated with snoring and sleep apnea, morning headaches are not specific for any primary sleep disorder. Nevertheless, the management of the sleep disorder ameliorates both morning headache and migraine.Noxious stimuli administered into muscles during slow-wave sleep (SWS) result in decreases in delta and sigma but an increase in alpha and beta EEG frequencies during sleep. Noise stimuli that disrupt SWS result in unrefreshing sleep, diffuse musculoskeletal pain, tenderness, and fatigue in normal healthy subjects. Such symptoms accompany alpha EEG sleep patterns that often occur in patients with fibromyalgia. The alpha EEG patterns include phasic and tonic alpha EEG sleep as well as periodic K alpha EEG sleep or frequent periodic cyclical alternating pattern. Moreover, alpha EEG sleep, as well as sleep-related breathing disorder and periodic limb movement disorder, occur in some patients with fibromyalgia, rheumatoid arthritis and osteoarthritis. Depression and not alpha EEG sleep are features of somatoform pain disorder. Disturbances in sleep, pain behaviour and psychological distress influence return to work in workers who have suffered a soft tissue injury, e.g. low back pain. Patients with irritable bowel disorder have disturbed sleep and have increased REM sleep. In conclusion, there is a reciprocal relationship between sleep quality and pain. The recognition of disturbed or unrefreshing sleep influences the management of painful medical disorders.

Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders

OBJECTIVE

To identify antinuclear antibodies (ANA) specific for chronic fatigue syndrome (CFS), and in related conditions such as fibromyalgia (FM) or psychiatric disorders.

METHODS

One hundred and fourteen CFS patients and 125 primary and secondary FM patients were selected based on criteria advocated by the Centers for Disease Control and Prevention and by the American College of Rheumatology, respectively. As controls, healthy subjects and patients with either various psychiatric disorders or diffuse connective tissue diseases were included. Autoantibodies were examined by immunoblot utilizing HeLa cell extracts as the antigen.

RESULTS

Autoantibodies to a 68/48 kDa protein were present in 13.2 and 15.6% of patients with CFS and primary FM, respectively. In addition, autoantibodies to a 45 kDa protein were found in 37.1 and 21.6% of the patients with secondary FM and psychiatric disorders, respectively. Meanwhile, these two autoantibodies were not found at all in connective tissue disease patients without FM, nor in healthy subjects (P<0.05). As a group, the anti-68/48 kDa-positive CFS patients presented more frequently with hypersomnia (P<0.005), short-term amnesia (P<0.07) or difficulty in concentration (P<0.05) than those CFS patients without the antibodies.

CONCLUSIONS

The presence of the anti-68/48 kDa protein antibodies in a portion of both CFS and primary FM patients suggests the existence of a common immunological background. These antibodies may find utility as possible markers for a clinicoserological subset of CFS/FM patients with hypersomnia and cognitive complaints.

Serotonergic markers and lowered plasma branched-chain-amino acid concentrations in fibromyalgia

The aims of the present study were to examine serotonergic markers, i.e. [3H]paroxetine binding characteristics and the availability of plasma tryptophan, the precursor of serotonin (5-HT), and the plasma concentrations of the branched chain amino acids (BCAAs), valine, leucine and isoleucine, in fibromyalgia. The [3H]paroxetine binding characteristics, B(max) and K(d) values, and tryptophan and the competing amino acids (CAA), known to compete for the same cerebral uptake mechanism (i.e. valine, leucine, isoleucine, phenylalanine and tyrosine), were determined in fibromyalgia patients and normal controls. There were no significant differences in the [3H]paroxetine binding characteristics (B(max) and K(d)) between fibromyalgia and control subjects. There were no significant differences in plasma tryptophan or the tryptophan/CAA ratio between fibromyalgia patients and normal controls. In the fibromyalgia patients, there were no significant correlations between [3H]paroxetine binding characteristics or the availability of tryptophan and myalgic or depressive symptoms. Patients with fibromyalgia had significantly lower plasma concentrations of the three BCAAs (valine, leucine and isoleucine) and phenylalanine than normal controls. It is hypothesized that the relative deficiency in the BCAAs may play a role in the pathophysiology of fibromyalgia, since the BCAAs supply energy to the muscle and regulate protein synthesis in the muscles. A supplemental trial with BCAAs in fibromyalgia appears to be justified.

The immune-inflammatory pathophysiology of fibromyalgia: increased serum soluble gp130, the common signal transducer protein of various neurotrophic cytokines

Fibromyalgia is a chronic, painful musculoskeletal disorder characterized by widespread pain, pressure hyperalgesia, morning stiffness and by an increased incidence of depressive symptoms. The etiology, however, has remained elusive. The aim of the present study was to examine the inflammatory response system (IRS) in fibromyalgia. Serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), sgp130, sIL-1R antagonist (IL-1RA) and sCD8 were determined in 33 healthy volunteers and in 21 fibromyalgia patients, classified according to the American College of Rheumatology criteria. Severity of illness was measured with several pain scales, dolorimetry and the Hamilton Depression Rating Scale (HDRS). Serum sgp130 was significantly higher and serum sCD8 significantly lower in fibromyalgia patients than in healthy volunteers. Serum sIL-6R and sIL-1RA were significantly higher in fibromyalgia patients with an increased HDRS score (> or = 16) than in normal volunteers and fibromyalgia patients with a HDRS score < 16. In fibromyalgia patients, an important part of the variance in sCD8 (50.3%) and IL-1RA (19.3%) could be explained by the HDRS score; 74.3% of the variance in sIL-6R was explained by the combined effects of pain symptoms and the HDRS score; and 25.9% of the variance in serum sgp130 was explained by stiffness. The results support the contention that pain and stiffness in fibromyalgia may be accompanied by a suppression of some aspects of the IRS and that the presence of clinically significant depressive symptoms in fibromyalgia is associated with some signs of IRS activation.

Circadian studies of autonomic nervous balance in patients with fibromyalgia: a heart rate variability analysis

OBJECTIVE

To determine the accumulated 24-hour cardiovascular autonomic modulation and its circadian variations in patients with fibromyalgia, by means of heart rate variability analysis.

METHODS

Thirty patients with fibromyalgia and 30 age- and sex-matched controls were studied prospectively. Assessments included a 24-hour ambulatory recording of heart rate variability, time-domain analysis of the accumulated 24-hour R-R interval variations, and power spectral analysis to determine the sympatho/ vagal balance at different hours (calculated as the power spectral density of the low-frequency [0.04-0.15-Hz] sympathetic band divided by the power of the high-frequency [0.15-0.50-Hz] parasympathetic band).

RESULTS

Fibromyalgia patients had diminished accumulated 24-hour heart rate variability, manifested by a decreased standard deviation of all R-R intervals (mean +/- SD 126 +/- 35 ms, versus 150 +/- 33 ms in controls; P = 0.008) and a decreased ratio of pairs of adjacent R-R intervals differing by >50 ms (mean +/- SD 12.0 +/- 9.0% versus 20.1 +/- 18.0%; P = 0.031). Patients lost the circadian variations of sympatho/vagal balance, with nocturnal values significantly higher than those of controls at time 0 (mean +/- SD 3.5 +/- 3.2 versus 1.2 +/- 1.0; P = 0.027) and at 3 hours (3.3 +/- 3.0 versus 1.6 +/- 1.4; P = 0.01).

CONCLUSION

Individuals with fibromyalgia have diminished 24-hour heart rate variability due to an increased nocturnal predominance of the low-frequency band oscillations consistent with an exaggerated sympathetic modulation of the sinus node. This abnormal chronobiology could explain the sleep disturbances and fatigue that occur in this syndrome. Spectral analysis of heart rate variability may be a useful test to identify fibromyalgia patients who have dysautonomia.

Sleep disorders presenting as psychiatric disorders

In summary, disordered sleep can present in a complex and atypical fashion in which the primary sleep-related component may not be immediately apparent. A high index of suspicion serves the clinician well in these cases. A careful and systematic evaluation of sleep often proves to be rewarding in terms of diagnostic accuracy and improved treatment outcome.

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.

The effect of reproductive events and alterations of sex hormone levels on the symptoms of fibromyalgia

The fibromyalgia syndrome (FS) is a chronic pain disorder frequently affecting women of fertile age. However, the relationship of FS and pregnancy has been given little attention. In the present retrospective analysis, based on personal interviews, the influence on FS symptomatology by pregnancy, abortion, menstruation, use of oral contraceptives, and breast feeding was investigated. Twenty-six women with an established diagnosis of FS and a total of 40 pregnancies during disease were included in the study. With the exception of one patient, all women described worsening fibromyalgia symptoms during pregnancy with the last trimester experienced as the worst period. A new change of fibromyalgia symptoms within 6 months after delivery was reported for 37 of the 40 pregnancies, to the better in four and to the worse in 33 cases, resulting in a prolonged sick leave for 14 patients. An increase in depression and anxiety was a prominent problem in the post partum period. FS had no adverse effect on the outcome of pregnancy or the health of the neonate. In the majority of patients with FS, hormonal changes connected with abortion, use of hormonal contraceptives, and breast feeding did not modulate symptom severity. A pre-menstrual worsening of symptoms was recorded by 72% of the patients. Comparing the 26 patients who had borne children during disease with 18 patients who had all their children before the onset of FS revealed a negative effect of pregnancy and the post partum period of FS and increased functional impairment and disability in the 26 patients.

Use of the Hamilton and Montgomery-Asberg Depression Scales in Institutionalized Elderly Patients

In screening for a study of drug treatment of major depression, the authors obtained data on depressive symptoms in elderly residential care patients (N = 116; average age 84 years; 81% women). Principal-components analysis (with varimax rotation) of the Hamilton Rating Scale for Depression yielded a four-factor solution (accounting for 47.2% of variance): core depression, anxiety, insomnia-hypochondriasis, and cognitive-ideational symptoms. The Montgomery-Asberg Depression Scale yielded two factors (54% of variance)-core depression and anxiety. Core depression factor scores from both scales (but not other factor scores) predicted mortality. The association of core depression with mortality (in subsets of patients for which data on these covariates were available) remained significant after measures of illness burden and disability were controlled.

Influence of host defense activation on sleep in humans

Despite considerable progress in our understanding of the phenomenology of sleep and wakefulness, their regulation and peculiar functions are poorly understood. Recent animal research has revealed considerable evidence for interactions between host defense and sleep. Therefore, it has been hypothesized that host response mediators, mainly cytokines like interleukin-1 (IL-1), are involved in physiological sleep regulation. Furthermore, it has been suggested that sleep, and non rapid eye movement (NREM) sleep in particular, has an immuno-supportive function. In humans, sleep-host defense interactions are just starting to be understood. There is quite good evidence that some viral diseases cause excessive sleepiness. Other infectious diseases induce, however, serious disturbances of the distribution of sleep and wakefulness rather than excessive sleep. In addition, some disorders with excessive sleep, daytime fatigue or disturbed night sleep as prominent symptoms are thought to involve, at least in part, immuno-pathophysiological mechanisms. Experimental settings have only recently been used to elucidate host defense-sleep interactions in humans. The effects of endotoxin, a cell-wall lipopolysaccharide of gram-negative bacteria, on sleep have been tested in different settings in healthy volunteers. Endotoxin transiently suppresses rapid eye movement (REM) sleep independently of the time of the day of administration. Only low doses, given in the evening, promote NREM sleep. Electorencephalogram (EEG) power in higher frequency bands is enhanced during NREM sleep, whereas delta activity is not affected. In rats and rabbits, on the other hand, the effects of endotoxin and of the mediators of its activity on REM sleep are variable. Enhanced NREM sleep is a common finding and most pronounced during the active part of the nycthemeron and, in general, EEG delta activity is augmented. In view of these species differences, hypotheses regarding the underlying mechanisms and the biological significance of host defense-sleep interactions, primarily derived from the results of animal studies, may not entirely fit human physiology. They should therefore be re-evaluated and probably modified, through the use of additional experimental approaches in humans.