Altered neuroendocrine control and association to clinical symptoms in adolescent chronic fatigue syndrome: a cross-sectional study

Exploring levels of TSH and FT4 in patients with chronic fatigue syndrome (CFS), fibromyalgia (FM) and healthy controls did not reveal any associations between fatigue score and level of thyroid hormones

AIM

The diagnoses of Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) are highly associated with fatigue and pain, respectively. Physiologically and clinically an effect of thyroid status on fatigue and pain is expected. There may be clinically relevant differences in thyroid hormone axes though within values of reference in both patients with normal thyroid hormones, or in patients with well-regulated thyroid disease. These potential differences are explored in this study.

MATERIALS AND METHODS

In the present study, female patients with CFS (n = 49) and FM (n = 58) as well as female healthy controls (n = 53) were included. We explored plasma levels of TSH and FT4 between the groups using Kruskall-Wallis, and the relation between fatigue score and levels of TSH and FT4 by means of Spearman's rho.

RESULTS

There were no group differences between CFS patients, FM patients, and healthy controls in levels of TSH and FT4.

CONCLUSION

As one might clinically and physiologically expect an association between thyroid function and fatigue, which may be associated with clinical disorders such as CFS and FM, we suggest future studies to examine the field further by exploring the influence of thyroid receptors and responses of the thyroid hormone cascade.

Effects of physical activity in child and adolescent depression and anxiety: role of inflammatory cytokines and stress-related peptide hormones

Depression and anxiety are the most common mental illnesses affecting children and adolescents, significantly harming their well-being. Research has shown that regular physical activity can promote cognitive, emotional, fundamental movement skills, and motor coordination, as a preventative measure for depression while reducing the suicide rate. However, little is known about the potential role of physical activity in adolescent depression and anxiety. The studies reviewed in this paper suggest that exercise can be an effective adjunctive treatment to improve depressive and anxiety symptoms in adolescents, although research on its neurobiological effects remains limited.

Long COVID in Children: A Multidisciplinary Review

Long COVID syndrome has emerged as a long-lasting consequence of acute SARS-CoV-2 infection in adults. In addition, children may be affected by Long COVID, with potential clinical issues in different fields, including problems in school performance and daily activities. Yet, the pathophysiologic bases of Long COVID in children are largely unknown, and it is difficult to predict who will develop the syndrome. In this multidisciplinary clinical review, we summarise the latest scientific data regarding Long COVID and its impact on children. Special attention is given to diagnostic tests, in order to help the physicians to find potential disease markers and quantify impairment. Specifically, we assess the respiratory, upper airways, cardiac, neurologic and motor and psychological aspects. Finally, we also propose a multidisciplinary clinical approach.

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature

Some patients remain unwell for months after "recovering" from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars. In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

Comparison of a 20 degree and 70 degree tilt test in adolescent myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients

Introduction

During a standard 70-degree head-up tilt test, 90% of adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) develop an abnormal reduction in cerebral blood flow (CBF). A 70-degree test might not be tolerated by young ME/CFS patients because of the high incidence of syncopal spells. This study examined whether a test at 20 degrees would be sufficient to provoke important reductions in CBF in young ME/CFS patients.

Methods

We analyzed 83 studies of adolescent ME/CFS patients. We assessed CBF using extracranial Doppler measurements of the internal carotid and vertebral arteries supine and during the tilt. We studied 42 adolescents during a 20 degree and 41 during a 70 degree test.

Results

At 20 degrees, no patients developed postural orthostatic tachycardia (POTS), compared to 32% at 70 degrees (p = 0.0002). The CBF reduction during the 20 degree tilt of -27(6)% was slightly less than during the reduction during a 70 degree test [-31(7)%; p = 0.003]. Seventeen adolescents had CBF measurements at both 20 and 70 degrees. The CBF reduction in these patients with both a 20 and 70 degrees test was significantly larger at 70 degrees than at 20 degrees (p < 0.0001).

Conclusions

A 20 degree tilt in young ME/CFS patients resulted in a CBF reduction comparable to that in adult patients during a 70 degree test. The lower tilt angle provoked less POTS, emphasizing the importance of using the 70 degree angle for that diagnosis. Further study is needed to explore whether CBF measurements during tilt provide an improved standard for classifying orthostatic intolerance.

Mixed Depression in the Post-COVID-19 Syndrome: Correlation between Excitatory Symptoms in Depression and Physical Burden after COVID-19

The relationship between depression and post-COVID-19 disease syndrome (post-COVID-19 syndrome) is established. Nevertheless, few studies have investigated the association between post-COVID-19 syndrome and mixed depression, i.e., a specific sub-form of depression characterized by high level of excitatory symptoms. Aims of the present study are: (a) to compare the post-COVID-19 syndrome's burden in depressed and non-depressed patients, and (b) to investigate the correlation between post-COVID-19 syndrome's burden and the severity of mixed depression. One thousand and forty six (n = 1460) subjects with post-COVID-19 syndrome were assessed. Subjects were divided into those with (DEP) or without (CONT) depression. Sociodemographically, post-COVID-19 syndrome's symptoms number and type were compared. In DEP, association between levels of excitatory symptoms and the presence of post-COVID-19 syndrome's symptoms were additionally assessed. DEP showed greater percentages of family history of psychiatric disorders than CONT. DEP showed higher percentages of post-COVID-19 symptoms than CONT. A greater level of excitatory symptoms were associated to higher frequencies of post-COVID-19 syndrome' symptoms. Higher levels of post-COVID-19 syndrome's symptoms in DEP corroborate the evidence of a common pathway between these two syndromes. Presence of excitatory symptoms seem to additionally add a greater illness burden. Such findings might help clinicians choose the appropriate treatment for such states. More specifically, therapies aimed to treat excitatory symptoms, such as antipsychotics and mood stabilizers, might help reduce the illness burden in post-COVID-19 patients with mixed depression.

Cortisol and α-amylase awakening response in children and adolescents with functional neurological (conversion) disorder

OBJECTIVE

Stress system dysregulation is considered to have an important role in the aetiology of paediatric functional neurological (conversion) disorder. This study examined salivary cortisol and α-amylase awakening responses in children with functional neurological disorder to determine activation patterns of the hypothalamic-pituitary-adrenal axis and sympathetic system. A healthy cortisol awakening response involves a robust increase in cortisol within 30 minutes of awakening. Alpha-amylase awakening response is variable in children.

METHODS

Cortisol and α-amylase were measured in saliva from 32 patients with functional neurological disorder (26 girls and 6 boys, aged 11.3-16.1 years) and 31 healthy controls (23 girls and 8 boys, aged 8.6-17.7 years). Saliva samples were collected using a Salivette sampling device at two time points - upon awakening and 30 minutes after awakening.

RESULTS

Patients with functional neurological disorder showed a decrease in cortisol awakening response (-4 nmol.min/L) and controls showed an increase (107 nmol.min/L), t(55) = -.4.6, p < 0.001. Within the functional neurological disorder group, 57% showed an attenuated cortisol awakening response and 43% showed an obliterated/reversed cortisol awakening response: Cortisol awakening response was negatively correlated with adverse childhood experiences, r(58) = -0.6, p = 0.002, and subjective distress (total Depression Anxiety and Stress Scales score), r(58) = -0.4, p = 0.050. In controls, cortisol awakening response showed no correlation with adverse childhood experiences and a positive correlation with subjective distress, r(56) = 0.4, p = 0.023. Total cortisol remained similar between the functional neurological disorder and control group. No significant differences were observed between the functional neurological disorder and control group in any of the α-amylase analyses.

DISCUSSION

The results suggest dysregulation of the hypothalamic-pituitary-adrenal axis in children with functional neurological disorder. Hypothalamic-pituitary-adrenal dysregulation in children with functional neurological disorder may contribute to comorbid symptoms of fatigue, sleep disturbance and subjective loss of well-being because circadian rhythms and energy metabolism are disrupted. Hypothalamic-pituitary-adrenal dysregulation - and changes in glucocorticoid (cortisol) signalling at the molecular level - may also contribute to increased vulnerability for functional neurological disorder symptoms because of epigenetically mediated changes to neural networks implicated in functional neurological disorder.

Neurovascular Dysregulation and Acute Exercise Intolerance in ME/CFS: A Randomized, Placebo-Controlled Trial of Pyridostigmine

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by intractable fatigue, postexertional malaise, and orthostatic intolerance, but its pathophysiology is poorly understood. Pharmacologic cholinergic stimulation was used to test the hypothesis that neurovascular dysregulation underlies exercise intolerance in ME/CFS.

RESEARCH QUESTION

Does neurovascular dysregulation contribute to exercise intolerance in ME/CFS, and can its treatment improve exercise capacity?

STUDY DESIGN AND METHODS

Forty-five subjects with ME/CFS were enrolled in a single-center, randomized, double-blind, placebo-controlled trial. Subjects were assigned in a 1:1 ratio to receive a 60-mg dose of oral pyridostigmine or placebo after an invasive cardiopulmonary exercise test (iCPET). A second iCPET was performed 50 min later. The primary end point was the difference in peak exercise oxygen uptake (Vo₂). Secondary end points included exercise pulmonary and systemic hemodynamics and gas exchange.

RESULTS

Twenty-three subjects were assigned to receive pyridostigmine and 22 to receive placebo. The peak Vo₂ increased after pyridostigmine but decreased after placebo (13.3 ± 13.4 mL/min vs -40.2 ± 21.3 mL/min; P < .05). The treatment effect of pyridostigmine was 53.6 mL/min (95% CI, -105.2 to -2.0). Peak vs rest Vo₂ (25.9 ± 15.3 mL/min vs -60.8 ± 25.6 mL/min; P < .01), cardiac output (-0.2 ± 0.6 L/min vs -1.9 ± 0.6 L/min; P < .05), and right atrial pressure (1.0 ± 0.5 mm Hg vs -0.6 ± 0.5 mm Hg; P < .05) were greater in the pyridostigmine group compared with placebo.

INTERPRETATION

Pyridostigmine improves peak Vo₂ in ME/CFS by increasing cardiac output and right ventricular filling pressures. Worsening peak exercise Vo₂, cardiac output, and right atrial pressure following placebo may signal the onset of postexertional malaise. We suggest that treatable neurovascular dysregulation underlies acute exercise intolerance in ME/CFS.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03674541; URL: www.

CLINICALTRIALS

gov.

Effect of Di-(2-ethylhexyl) phthalate on the hypothalamus-pituitary-thyroid axis in adolescent rat

Di-(2-ethylhexyl) phthalate (DEHP) is extensively used in many personal care and consumer products, which results in widespread human exposure. Limited studies have suggested that exposure to DEHP may affect thyroid function, but little is known about the effect and mechanisms of DEHP exposure on the hypothalamic-pituitary-thyroid axis (HPTA). The present study was conducted to elucidate the potential mechanisms underlying DEHP disrupting the function of the HPTA. DEHP was administered to Wistar rats by gavage at 0, 5, 50, and 500 mg/kg/day for consecutive 28 days and then the rats were sacrificed within 24 h following the last dose. The hormone levels of HPTA were quantified with radioimmunoassay and enzyme-linked immunosorbent assay, the protein levels of thyrotropin-releasing hormone receptor (TRHR) and thyroid-stimulating hormone receptor (TSHR) were analyzed by Western blot and immunohistochemistry, and the expression levels of TRHR and TSHR mRNA were measured by quantitative real-time PCR. The low dose of DEHP increased the body weights of rats. Serum levels of T3, T4, FT3 and FT4 as well as protein and mRNA levels of TSHR decreased in rats treated with 50 mg/kg or 500 mg/kg DEHP compared with those of controls. Although the protein levels of TRH in the hypothalamus or protein and mRNA levels of TRHR in pituitary were up-regulated, serum levels of TSH did not change statistically in rats treated with DEHP. Therefore, DEHP can produce thyroid toxicity and may interfere with the secretion of pituitary TSH. In conclusion, DEHP could interfere with the balance of HPTA of adolescent rats, and disturb the homeostasis of thyroid related hormones and the expression levels of receptors.

Circadian Rhythm Effects on the Molecular Regulation of Physiological Systems

Nearly every system within the body contains an intrinsic cellular circadian clock. The circadian clock contributes to the regulation of a variety of homeostatic processes in mammals through the regulation of gene expression. Circadian disruption of physiological systems is associated with pathophysiological disorders. Here, we review the current understanding of the molecular mechanisms contributing to the known circadian rhythms in physiological function. This article focuses on what is known in humans, along with discoveries made with cell and rodent models. In particular, the impact of circadian clock components in metabolic, cardiovascular, endocrine, musculoskeletal, immune, and central nervous systems are discussed. © 2021 American Physiological Society. Compr Physiol 11:1-30, 2021.

Evaluating Routine Blood Tests According to Clinical Symptoms and Diagnostic Criteria in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

There is a lack of research regarding blood tests within individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and between patients and healthy controls. We aimed to compare results of routine blood tests between patients and healthy controls. Data from 149 patients diagnosed with ME/CFS based on clinical and psychiatric evaluation as well as on the DePaul Symptom Questionnaire, and data from 264 healthy controls recruited from blood donors were compared. One-way ANCOVA was conducted to examine differences between ME/CFS patients and healthy controls, adjusting for age and gender. Patients had higher sedimentation rate (mean difference: 1.38, 95% CI: 0.045 to 2.714), leukocytes (mean difference: 0.59, 95% CI: 0.248 to 0.932), lymphocytes (mean difference: 0.27, 95% CI: 0.145 to 0.395), neutrophils (mean difference: 0.34, 95% CI: 0.0 89 to 0.591), monocytes (mean difference: 0.34, 95% CI: 0.309 to 0.371), ferritin (mean difference: 28.13, 95% CI: −1.41 to 57.672), vitamin B12 (mean difference: 83.43, 95% CI: 62.89 to 124.211), calcium (mean difference: 0.02, 95% CI: −0.02 to 0.06), alanine transaminase (mean difference: 3.30, 95% CI: −1.37 to -7.971), low-density lipoproteins (mean difference: 0.45, 95% CI: 0.104 to 0.796), and total proteins (mean difference: 1.53, 95% CI: −0.945 to 4.005) than control subjects. The patients had lower potassium levels (mean difference: 0.11, 95% CI: 0.056 to 0.164), creatinine (mean difference: 2.60, 95% CI: 0.126 to 5.074) and creatine kinase (CK) (mean difference: 37.57, 95% CI: −0.282 to 75.422) compared to the healthy controls. Lower CK and creatinine levels may suggest muscle damage and metabolic abnormalities in ME/CFS patients.

An Exploratory Analysis of the Association Between Catechol-O-Methyltransferase and Response to a Randomized Open-Label Placebo Treatment for Cancer-Related Fatigue

Previous studies have identified catechol-O-methyltransferase (COMT), as a key enzyme influencing sympathetic function. Although the COMT SNP rs4680 and rs4818, are well-studied, little is known about their influence on cancer-related fatigue (CrF) and placebo response. In this study, we examined whether genetic variation in COMT, at the functional SNP rs4680 and linked rs4818, influenced open-label placebo (OLP) responses found in cancer survivors reporting moderate to severe CrF. We randomized cancer survivors (N = 74) reporting moderate-to-severe CrF to receive OLP or to treatment-as-usual (TAU) and assessed if rs4680 and rs4818 were associated with changes in fatigue severity and fatigue-distressed quality of life. At the end of the initial 21 days, the treatments were crossed over and both groups were re-assessed. Participants with the rs4680 high-activity G-allele (G/G or G/A) or rs4818 C/G genotypes reported significant decreases in fatigue severity and improvements in fatigue-distressed quality of life. The COMT rs4818 findings replicated findings in a similar study of OLP in cancer fatigue. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02522988.

Endothelial Senescence and Chronic Fatigue Syndrome, a COVID-19 Based Hypothesis

Myalgic encephalomyelitis/chronic fatigue syndrome is a serious illness of unknown etiology, characterized by debilitating exhaustion, memory impairment, pain and sleep abnormalities. Viral infections are believed to initiate the pathogenesis of this syndrome although the definite proof remains elusive. With the unfolding of COVID-19 pandemic, the interest in this condition has resurfaced as excessive tiredness, a major complaint of patients infected with the SARS-CoV-2 virus, often lingers for a long time, resulting in disability, and poor life quality. In a previous article, we hypothesized that COVID-19-upregulated angiotensin II triggered premature endothelial cell senescence, disrupting the intestinal and blood brain barriers. Here, we hypothesize further that post-viral sequelae, including myalgic encephalomyelitis/chronic fatigue syndrome, are promoted by the gut microbes or toxin translocation from the gastrointestinal tract into other tissues, including the brain. This model is supported by the SARS-CoV-2 interaction with host proteins and bacterial lipopolysaccharide. Conversely, targeting microbial translocation and cellular senescence may ameliorate the symptoms of this disabling illness.

Pathophysiology of skeletal muscle disturbances in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Chronic Fatigue Syndrome or Myalgic Encephaloymelitis (ME/CFS) is a frequent debilitating disease with an enigmatic etiology. The finding of autoantibodies against ß2-adrenergic receptors (ß2AdR) prompted us to hypothesize that ß2AdR dysfunction is of critical importance in the pathophysiology of ME/CFS. Our hypothesis published previously considers ME/CFS as a disease caused by a dysfunctional autonomic nervous system (ANS) system: sympathetic overactivity in the presence of vascular dysregulation by ß2AdR dysfunction causes predominance of vasoconstrictor influences in brain and skeletal muscles, which in the latter is opposed by the metabolically stimulated release of endogenous vasodilators (functional sympatholysis). An enigmatic bioenergetic disturbance in skeletal muscle strongly contributes to this release. Excessive generation of these vasodilators with algesic properties and spillover into the systemic circulation could explain hypovolemia, suppression of renin (paradoxon) and the enigmatic symptoms. In this hypothesis paper the mechanisms underlying the energetic disturbance in muscles will be explained and merged with the first hypothesis. The key information is that ß2AdR also stimulates the Na+/K+-ATPase in skeletal muscles. Appropriate muscular perfusion as well as function of the Na+/K+-ATPase determine muscle fatigability. We presume that dysfunction of the ß2AdR also leads to an insufficient stimulation of the Na+/K+-ATPase causing sodium overload which reverses the transport direction of the sodium-calcium exchanger (NCX) to import calcium instead of exporting it as is also known from the ischemia-reperfusion paradigm. The ensuing calcium overload affects the mitochondria, cytoplasmatic metabolism and the endothelium which further worsens the energetic situation (vicious circle) to explain postexertional malaise, exercise intolerance and chronification. Reduced Na+/K+-ATPase activity is not the only cause for cellular sodium loading. In poor energetic situations increased proton production raises intracellular sodium via sodium-proton-exchanger subtype-1 (NHE1), the most important proton-extruder in skeletal muscle. Finally, sodium overload is due to diminished sodium outward transport and enhanced cellular sodium loading. As soon as this disturbance would have occurred in a severe manner the threshold for re-induction would be strongly lowered, mainly due to an upregulated NHE1, so that it could repeat at low levels of exercise, even by activities of everyday life, re-inducing mitochondrial, metabolic and vascular dysfunction to perpetuate the disease.

Are there subgroups of chronic fatigue syndrome? An exploratory cluster analysis of biological markers

Background

Chronic fatigue syndrome (CFS) is defined according to subjective symptoms only, and several conflicting case definition exist. Previous research has discovered certain biological alterations. The aim of the present study was to explore possible subgroups based on biological markers within a widely defined cohort of adolescent CFS patients and investigate to what extent eventual subgroups are associated with other variables.

Methods

The Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial (NorCAPITAL) has previously performed detailed investigation of immunological, autonomic, neuroendocrine, cognitive and sensory processing functions in an adolescent group of CFS patients recruited according to wide diagnostic criteria. In the present study, hierarchical cluster analyses (Ward’s method) were performed using representative variables from all these domains. Associations between clusters and constitutional factors (including candidate genetic markers), diagnostic criteria, subjective symptoms and prognosis were explored by standard statistical methods.

Results

A total of 116 patients (26.7% males, mean age 15.4 years) were included. The final cluster analyses revealed six clusters labelled pain tolerant & good cognitions, restored HPA dynamics, orthostatic intolerance, low-grade inflammation, pain intolerant & poor cognitions, and high vagal (parasympathetic) activity, respectively. There was substantial overlap between clusters. The pain intolerant & poor cognitions-cluster was associated with low functional abilities and quality of life, and adherence to the Canada 2003 diagnostic criteria for CFS. No other statistically significant cluster associations were discovered.

Conclusion

Within a widely defined cohort of adolescent CFS patients, clusters could be delineated, but no distinct subgroups could be identified. Associations between clusters and constitutional factors, subjective symptoms and prognosis were scarce. These results question the clinical usefulness of searching for CFS subgroups, as well as the validity of the most “narrow” CFS diagnostic criteria.

Trial registration: Clinical Trials NCT01040429

Validation of the Severity of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome by Other Measures than History: Activity Bracelet, Cardiopulmonary Exercise Testing and a Validated Activity Questionnaire: SF-36

Introduction: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severe and disabling chronic disease. Grading patient’s symptom and disease severity for comparison and therapeutic decision-making is necessary. Clinical grading that depends on patient self-report is subject to inter-individual variability. Having more objective measures to grade and confirm clinical grading would be desirable. Therefore, the aim of this study was to validate the clinical severity grading that has been proposed by the authors of the ME International Consensus Criteria (ICC) using more standardized measures like questionnaires, and objective measures such as physical activity tracking and cardiopulmonary exercise testing. Methods and results: The clinical database of a subspecialty ME/CFS clinic was searched for patients who had completed the SF 36 questionnaire, worn a Sensewear^TM armband for five days, and undergone a cardiopulmonary exercise test. Only patients who completed all three investigations within 3 months from each other—to improve the likelihood of stable disease—were included in the analysis. Two-hundred-eighty-nine patients were analyzed: 121 were graded as mild, 98 as moderate and 70 as having severe disease. The mean (SD) physical activity subscale of the SF-36 was 70 (11) for mild, 43 (8) for moderate and 15 (10) for severe ME/CFS patients. The mean (SD) number of steps per day was 8235 (1004) for mild, 5195 (1231) for moderate and 2031 (824) for severe disease. The mean (SD) percent predicted oxygen consumption at the ventilatory threshold was 47 (11)% for mild, 38 (7)% for moderate and 30 (7)% for severe disease. The percent peak oxygen consumption was 90 (14)% for mild, 64 (8)% for moderate and 48 (9)% for severe disease. All comparisons were p < 0.0001. Conclusion: This study confirms the validity of the ICC severity grading. Grading assigned by clinicians on the basis of patient self-report created groups that differed significantly on measures of activity using the SF-36 physical function subscale and objective measures of steps per day and exercise capacity. There was variability in function within severity grading groups, so grading based on self-report can be strengthened by the use of these supplementary measures.

IgG stimulated β2 adrenergic receptor activation is attenuated in patients with ME/CFS

Background

There is emerging evidence of a network of natural autoantibodies against GPCR which is dysregulated in various diseases. β2 adrenergic and M3 and M4 cholinergic receptor (β2 AdR and M3/4 mAChR) antibodies were found to be elevated in a subset of ME/CFS patients.

Methods

We comparatively analyzed the effects of polyclonal IgG on β2 AdR signaling and immune cell function in vitro. 16 IgG fractions were isolated from serum of 5 ME/CFS patients with elevated (CFS AAB_high) and 5 with normal levels (CFS AAB_norm) of β2 AdR autoantibodies, and from 6 healthy controls (HC). The effect of each IgG on β-arrestin recruitment and cAMP production in β2 AdR and M3/4R reporter cell lines was studied. Further effect of each IgG on human monocyte cytokine production and on T cell proliferation in vitro was analyzed. In addition, studies on cytokine production in β2 AdR wild type and knockout mice splenocytes incubated with IgG fractions were performed.

Results

We found that IgGs from HC could stimulate β-arrestin recruitment and cAMP production in β2 AdR reporter cell lines whereas IgGs from CFS AAB_high had no effect. The IgG-mediated activation of β2 AdR was confirmed in β2 AdR wt and ko mice. In accordance with previous studies IgG fractions from HC inhibited LPS-induced TNFα and stimulated LPS-induced IL-10 production of monocytes. Further IgG fractions from HC enhanced proliferation of T-cells stimulated with anti-CD3/CD28. IgG fractions from CFS AAB_high patients had no significant effect on both cytokine production and T cell proliferation, while IgGs from CFS AAB_norm had an intermediate effect. We could also observe that IgG can modulate the signaling of β2 AdR ligands isoprenline and propranolol.

Conclusions

We provide evidence that IgG can activate β2 AdR. The β2 AdR activation by IgG is attenuated in ME/CFS patients. A dysregulation of β2 AdR function could explain many symptoms of ME/CFS.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown aetiology that is recognized by the World Health Organization (WHO) and the United States Center for Disease Control and Prevention (US CDC) as a disorder of the brain. The disease predominantly affects adults, with a peak age of onset of between 20 and 45 years with a female to male ratio of 3:1. Although the clinical features of the disease have been well established within diagnostic criteria, the diagnosis of ME/CFS is still of exclusion, meaning that other medical conditions must be ruled out. The pathophysiological mechanisms are unclear but the neuro-immuno-endocrinological pattern of CFS patients gleaned from various studies indicates that these three pillars may be the key point to understand the complexity of the disease. At the moment, there are no specific pharmacological therapies to treat the disease, but several studies' aims and therapeutic approaches have been described in order to benefit patients' prognosis, symptomatology relief, and the recovery of pre-existing function. This review presents a pathophysiological approach to understanding the essential concepts of ME/CFS, with an emphasis on the population, clinical, and genetic concepts associated with ME/CFS.

Clinical symptoms and markers of disease mechanisms in adolescent chronic fatigue following Epstein-Barr virus infection: An exploratory cross-sectional study

INTRODUCTION

Acute Epstein-Barr virus (EBV) infection is a trigger of chronic fatigue (CF) and Chronic Fatigue Syndrome (CFS). The aim of this cross-sectional study was to explore clinical symptoms as well as markers of disease mechanisms in fatigued and non-fatigued adolescents 6 months after EBV-infection, and in healthy controls.

MATERIALS AND METHODS

A total of 200 adolescents (12-20 years old) with acute EBV infection were assessed 6 months after the initial infectious event and divided into fatigued (EBV CF+) and non-fatigued (EBV CF-) cases based on questionnaire score. The EBV CF+ cases were further sub-divided according to case definitions of CFS. In addition, a group of 70 healthy controls with similar distribution of sex and age was included. Symptoms were mapped with a questionnaire. Laboratory assays included EBV PCR and serology; detailed blood leukocyte phenotyping and serum high-sensitive C-reactive protein; and plasma and urine cortisol and catecholamines. Assessment of autonomic activity was performed with continuous, non-invasive monitoring of cardiovascular variables during supine rest, controlled breathing and upright standing. Differences between EBV CF+ and EBV CF- were assessed by simple and multiple linear regression adjusting for sex as well as symptoms of depression and anxiety. A p-value ≤ 0.05 was considered statistically significant. This study is part of the CEBA-project (Chronic fatigue following acute Epstein-Barr virus infection in adolescents).

RESULTS

The EBV CF+ group had significantly higher scores for all clinical symptoms. All markers of infection and most immune, neuroendocrine and autonomic markers were similar across the EBV CF+ and EBV CF- group. However, the EBV CF+ group had slightly higher serum C-reactive protein (0.48 vs 0.43 mg/L, p = 0.031, high-sensitive assay), total T cell (CD3+) count (median 1573 vs 1481 × 10⁶ cells/L, p = 0.012), plasma norepinephrine (1420 vs 1113 pmol/L, p = 0.01) and plasma epinephrine (363 vs 237 nmol/L, p = 0.032); lower low-frequency:high frequency (LF/HF) ratio of heart rate variability at supine rest (0.63 vs 0.76, p = 0.008); and an attenuated decline in LF/HF ratio during controlled breathing (-0.11 vs -0.25, p = 0.002). Subgrouping according to different CFS diagnostic criteria did not significantly alter the results. Within the EBV CF+ group, there were no strong correlations between clinical symptoms and markers of disease mechanisms. In a multiple regression analysis, serum CRP levels were independently associated with serum cortisol (B = 4.5 × 10^-4, p < 0.001), urine norepinephrine (B = 9.6 × 10^-2, p = 0.044) and high-frequency power of heart rate variability (B = -3.7 × 10^-2, p = 0.024).

CONCLUSIONS

In adolescents, CF and CFS 6 months after acute EBV infection are associated with high symptom burden, but no signs of increased viral load and only subtle alterations of immune, autonomic, and neuroendocrine markers of which no one is strongly correlated with symptom scores. A slight sympathetic over parasympathetic predominance is evident in CF and might explain slightly increased CRP levels.

Fatigue in Epstein-Barr virus infected adolescents and healthy controls: A prospective multifactorial association study

OBJECTIVE

Acute Epstein-Barr virus (EBV) infection is a known trigger of both acute and chronic fatigue. The aim of this study was to investigate associations to fatigue in adolescents with EBV infection during the initial stage and six months after, as well as in healthy controls.

METHODS

200 adolescents (12-20 years old) with EBV infection were assessed as soon as possible after the onset of symptoms (EBV_baseline) and six months later (EBV_{six months}, 5 drop-outs). Also, 70 healthy controls (HC) were included. Associations between current fatigue and 148 different variables (including symptoms, functional abilities and biomarkers) were investigated separately for EBV_baseline, EBV_{six months} and HC using linear regression modelling.

RESULTS

Fatigue was associated with symptoms of sleeping difficulties, negative emotions, and quality of life under all circumstances. Fatigue was independently associated with markers of immune response at EBV_{six months} and in HC, not at EBV_baseline. An association between fatigue and markers of autonomic cardiovascular control was only present at EBV_{six months}. Cognitive functioning shifted from a positive association to fatigue at EBV_baseline to a negative trend at EBV_{six months.} Markers of infection were not associated with fatigue at EBV_baseline, EBV_{six months} nor in HC.

CONCLUSION

Irrespective of the cause, fatigue is important for quality of life and is highly associated with negative emotions. Markers of infection and immune response had respectively none and barely any association to fatigue. Autonomic alterations and cognitive dysfunction were exclusively associated with fatigue long after infection, corroborating findings from studies of the Chronic Fatigue Syndrome.

Associations between clinical symptoms, plasma norepinephrine and deregulated immune gene networks in subgroups of adolescent with Chronic Fatigue Syndrome

BACKGROUND

Chronic Fatigue Syndrome (CFS) is one of the most important causes of disability among adolescents while limited knowledge exists on genetic determinants underlying disease pathophysiology.

METHODS

We analyzed deregulated immune-gene modules using Pathifier software on whole blood gene expression data (29 CFS patients, 18 controls). Deconvolution of immune cell subtypes based on gene expression profile was performed using CIBERSORT. Supervised consensus clustering on pathway deregulation score (PDS) was used to define CFS subgroups. Associations between PDS and immune, neuroendocrine/autonomic and clinical markers were examined. The impact of plasma norepinephrine level on clinical markers over time was assessed in a larger cohort (91 patients).

RESULTS

A group of 29 immune-gene sets was shown to differ patients from controls and detect subgroups within CFS. Group 1P (high PDS, low norepinephrine, low naïve CD4+ composition) had strong association with levels of serum C-reactive protein and Transforming Growth Factor-beta. Group 2P (low PDS, high norepinephrine, high naïve CD4+ composition) had strong associations with neuroendocrine/autonomic markers. The corresponding plasma norepinephrine level delineated 91 patients into two subgroups with significant differences in fatigue score.

CONCLUSION

We identified 29 immune-gene sets linked to plasma norepinephrine level that could delineate CFS subgroups. Plasma norepinephrine stratification revealed that lower levels of norepinephrine were associated with higher fatigue. Our data suggests potential involvement of neuro-immune dysregulation and genetic stratification in CFS.

Correction and Republication: Effect of Di-(2-ethylhexyl) phthalate on the hypothalamus-pituitary-thyroid axis in adolescent rat

Di-(2-ethylhexyl) phthalate (DEHP) is extensively used in many personal care and consumer products, which has resulted in widespread human exposure. Limited studies have suggested that exposure to DEHP may affect thyroid function, but little is known about the effect and mechanisms of DEHP exposure on the hypothalamic-pituitary-thyroid axis (HPTA). The present study was conducted to elucidate the potential mechanisms in which DEHP disrupts the function of the HPTA. Wistar rats were administered DEHP by gavage at 0, 5, 50, and 500 mg/kg/day for 28 days and then sacrificed within 24 h following the last dose. Hormones of HPTA was quantified with radioimmunoassay and enzyme-linked immunosorbent assay, protein levels of thyrotropin-releasing hormone receptor (TRHR) and thyroid-stimulating hormone receptor (TSHR) were analyzed by Western blot and immunohistochemistry, expression levels of TRHR and TSHR mRNA were measured by quantitative real-time PCR. Rats treated with DEHP resulted in increased bodyweight, on the HPTA, down-regulated the protein levels of TRH in the hypothalamus, up-regulated the protein and mRNA levels of TRHR in the pituitary, down-regulated mRNA expression of TSHR in the thyroid, while the difference of TSH in various dose groups was not statistically significant and T3, T4, FT3, FT4 levels in serum were decreased compared with control. DEHP could interfere with the balance of HPTA of adolescent rats, and increase the body weight, down-regulate the homeostasis of thyroid related hormones and receptors expression levels.

Childhood sleep and adolescent chronic fatigue syndrome (CFS/ME): evidence of associations in a UK birth cohort

OBJECTIVE/BACKGROUND

Sleep abnormalities are characteristic of chronic fatigue syndrome (CFS, also known as 'ME'), however it is unknown whether sleep might be a causal risk factor for CFS/ME.

PATIENTS/METHODS

We analysed data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. We describe sleep patterns of children aged 6 months to 11 years, who were subsequently classified as having (or not having) 'chronic disabling fatigue' (CDF, a proxy for CFS/ME) between the ages 13 and 18 years, and we investigated the associations of sleep duration at age nine years with CDF at age 13 years, as well as sleep duration at age 11 years with CDF at age 16 years.

RESULTS

Children who had CDF during adolescence had shorter night-time sleep duration from 6 months to 11 years of age, and there was strong evidence that difficulties in going to sleep were more common in children who subsequently developed CDF. The odds of CDF at age 13 years were 39% lower (odds ratio (OR) = 0.61, 95% CI = 0.43, 0.88) for each additional hour of night-time sleep at age nine years, and the odds of CDF at age 16 years were 51% lower (OR = 0.49, 95% CI = 0.34, 0.70) for each additional hour of night-time sleep at age 11 years. Mean night-time sleep duration at age nine years was 13.9 (95% CI = 3.75, 24.0) minutes shorter among children who developed CDF at age 13 years, and sleep duration at age 11 years was 18.7 (95% CI = 9.08, 28.4) minutes shorter among children who developed CDF at age 16 (compared with children who did not develop CDF at 13 and 16 years, respectively).

CONCLUSIONS

Children who develop chronic disabling fatigue in adolescence have shorter night-time sleep duration throughout early childhood, suggesting that sleep abnormalities may have a causal role in CFS/ME or that sleep abnormalities and CFS/ME are associated with a common pathophysiological cause.

Systemic exertion intolerance disease diagnostic criteria applied on an adolescent chronic fatigue syndrome cohort: evaluation of subgroup differences and prognostic utility

OBJECTIVE

Existing case definitions for chronic fatigue syndrome (CFS) all have disputed validity. The present study investigates differences between adolescent patients with CFS who satisfy the systemic exertion intolerance disease (SEID) diagnostic criteria (SEID-positive) and those who do not satisfy the criteria (SEID-negative).

METHODS

120 adolescent patients with CFS with a mean age of 15.4 years (range 12-18 years) included in the NorCAPITAL project (ClinicalTrials ID: NCT01040429) were post-hoc subgrouped according to the SEID criteria based on a comprehensive questionnaire. The two subgroups were compared across baseline characteristics, as well as a wide range of cardiovascular, inflammatory, infectious, neuroendocrine and cognitive variables. Data from 30-week follow-up were used to investigate prognostic differences between SEID-positive and SEID-negative patients.

RESULTS

A total of 45 patients with CFS were SEID-positive, 69 were SEID-negative and 6 could not be classified. Despite the fact that clinically depressed patients were excluded in the NorCAPITAL project, the SEID-positive group had significantly higher score on symptoms suggesting a mood disorder (Mood and Feelings Questionnaire): 23.2 vs 13.4, difference 9.19 (95% CI 5.78 to 12.6). No other baseline characteristics showed any group differences. When accounting for multiple comparisons, there were no statistically significant differences between the groups regarding cardiovascular, inflammatory, infectious, neuroendocrine and cognitive variables. Steps per day and Chalder Fatigue Questionnaire at week 30 showed no differences between the groups.

CONCLUSION

The findings question the discriminant and prognostic validity of the SEID diagnostic criteria in adolescent CFS, and suggest that the criteria tend to select patients with depressive symptoms.

Transforming growth factor beta (TGF-β) in adolescent chronic fatigue syndrome

BACKGROUND

Chronic fatigue syndrome (CFS) is a prevalent and disabling condition among adolescent. The disease mechanisms are unknown. Previous studies have suggested elevated plasma levels of several cytokines, but a recent meta-analysis of 38 articles found that of 77 different cytokines measured in plasma, transforming growth factor beta (TGF-β) was the only one that was elevated in patients compared to controls in a sufficient number of articles. In the present study we therefore compared the plasma levels of the three TGF-β isoforms in adolescent CFS patients and healthy controls. In addition, the study explored associations between TGF-β levels, neuroendocrine markers, clinical markers and differentially expressed genes within the CFS group.

METHODS

CFS patients aged 12-18 years (n = 120) were recruited nation-wide to a single referral center as part of the NorCAPITAL project (ClinicalTrials ID: NCT01040429). A broad case definition of CFS was applied, requiring 3 months of unexplained, disabling chronic/relapsing fatigue of new onset, whereas no accompanying symptoms were necessary. Healthy controls (n = 68) were recruited from local schools. The three isoforms of TGF-β (TGF-β1, TGF-β2, TGF-β3) were assayed using multiplex technology. Neuroendocrine markers encompassed plasma and urine levels of catecholamines and cortisol, as well as heart rate variability indices. Clinical markers consisted of questionnaire scores for symptoms of post-exertional malaise, inflammation, fatigue, depression and trait anxiety, as well as activity recordings. Whole blood gene expression was assessed by RNA sequencing in a subgroup of patients (n = 29) and controls (n = 18).

RESULTS

Plasma levels of all three isoforms of TGF-β were equal in the CFS patients and the healthy controls. Subgrouping according to the Fukuda and Canada 2003 criteria of CFS did not reveal differential results. Within the CFS group, all isoforms of TGF-β were associated with plasma cortisol, urine norepinephrine and urine epinephrine, and this association pattern was related to fatigue score. Also, TGF-β3 was related to expression of the B cell annotated genes TNFRSF13C and CXCR5.

CONCLUSIONS

Plasma levels of all TGF-β isoforms were not altered in adolescent CFS. However, the TGF-β isoforms were associated with neuroendocrine markers, an association related to fatigue score. Furthermore, TGF-β3 might partly mediate an association between plasma cortisol and B cell gene expression. Trial registration Clinical Trials NCT01040429.

Altered right anterior insular connectivity and loss of associated functions in adolescent chronic fatigue syndrome

Impairments in cognition, pain intolerance, and physical inactivity characterize adolescent chronic fatigue syndrome (CFS), yet little is known about its neurobiology. The right dorsal anterior insular (dAI) connectivity of the salience network provides a motivational context to stimuli. In this study, we examined regional functional connectivity (FC) patterns of the right dAI in adolescent CFS patients and healthy participants. Eighteen adolescent patients with CFS and 18 aged-matched healthy adolescent control participants underwent resting-state functional magnetic resonance imaging. The right dAI region of interest was examined in a seed-to-voxel resting-state FC analysis using SPM and CONN toolbox. Relative to healthy adolescents, CFS patients demonstrated reduced FC of the right dAI to the right posterior parietal cortex (PPC) node of the central executive network. The decreased FC of the right dAI–PPC might indicate impaired cognitive control development in adolescent CFS. Immature FC of the right dAI–PPC in patients also lacked associations with three known functional domains: cognition, pain and physical activity, which were observed in the healthy group. These results suggest a distinct biological signature of adolescent CFS and might represent a fundamental role of the dAI in motivated behavior.

Neuroendocrine disorder in chronic fatigue syndrome

Background/aim: Neuroendocrine disorders are considered a possible pathogenetic mechanism in chronic fatigue syndrome (CFS). The aim of our study was to determine the function of the hypothalamic-pituitary-adrenal axis (HPA) and thyroid function in women of reproductive age suffering from CFS. Materials and methods: The study included 40 women suffering from CFS and 40 healthy women (15-45 years old). Serum levels of cortisol (0800 and 1800 hours), ACTH, total T4, total T3, and TSH were measured in all subjects. The Fibro Fatigue Scale was used for determination of fatigue level. Results: Cortisol serum levels were normal in both groups. The distinctively positive moderate correlation of morning and afternoon cortisol levels that was observed in healthy women was absent in the CFS group. This may indicate a disturbed physiological rhythm of cortisol secretion. Although basal serum T4, T3, and TSH levels were normal in all subjects, concentrations of T3 were significantly lower in the CFS group. Conclusion: One-time hormone measurement is not sufficient to detect hormonal imbalance in women suffering from CFS. Absence of a correlation between afternoon and morning cortisol level could be a more representative factor for detecting HPA axis disturbance.

The European ME/CFS Biomarker Landscape project: an initiative of the European network EUROMENE

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a common and severe disease with a considerable social and economic impact. So far, the etiology is not known, and neither a diagnostic marker nor licensed treatments are available yet. The EUROMENE network of European researchers and clinicians aims to promote cooperation and advance research on ME/CFS. To improve diagnosis and facilitate the analysis of clinical trials surrogate markers are urgently needed. As a first step for developing such biomarkers for clinical use a database of active biomarker research in Europe was established called the ME/CFS EUROMENE Biomarker Landscape project and the results are presented in this review. Further we suggest strategies to improve biomarker development and encourage researchers to take these into consideration for designing and reporting biomarker studies.

Whole blood gene expression in adolescent chronic fatigue syndrome: an exploratory cross-sectional study suggesting altered B cell differentiation and survival

BACKGROUND

Chronic fatigue syndrome (CFS) is a prevalent and disabling condition affecting adolescents. The pathophysiology is poorly understood, but immune alterations might be an important component. This study compared whole blood gene expression in adolescent CFS patients and healthy controls, and explored associations between gene expression and neuroendocrine markers, immune markers and clinical markers within the CFS group.

METHODS

CFS patients (12-18 years old) were recruited nation-wide to a single referral center as part of the NorCAPITAL project. A broad case definition of CFS was applied, requiring 3 months of unexplained, disabling chronic/relapsing fatigue of new onset, whereas no accompanying symptoms were necessary. Healthy controls having comparable distribution of gender and age were recruited from local schools. Whole blood samples were subjected to RNA sequencing. Immune markers were blood leukocyte counts, plasma cytokines, serum C-reactive protein and immunoglobulins. Neuroendocrine markers encompassed plasma and urine levels of catecholamines and cortisol, as well as heart rate variability indices. Clinical markers consisted of questionnaire scores for symptoms of post-exertional malaise, inflammation, fatigue, depression and trait anxiety, as well as activity recordings.

RESULTS

A total of 29 CFS patients and 18 healthy controls were included. We identified 176 genes as differentially expressed in patients compared to controls, adjusting for age and gender factors. Gene set enrichment analyses suggested impairment of B cell differentiation and survival, as well as enhancement of innate antiviral responses and inflammation in the CFS group. A pattern of co-expression could be identified, and this pattern, as well as single gene transcripts, was significantly associated with indices of autonomic nervous activity, plasma cortisol, and blood monocyte and eosinophil counts. Also, an association with symptoms of post-exertional malaise was demonstrated.

CONCLUSION

Adolescent CFS is characterized by differential gene expression pattern in whole blood suggestive of impaired B cell differentiation and survival, and enhanced innate antiviral responses and inflammation. This expression pattern is associated with neuroendocrine markers of altered HPA axis and autonomic nervous activity, and with symptoms of post-exertional malaise. Trial registration Clinical Trials NCT01040429.