Neuroendocrine aspects of chronic fatigue syndrome

Impact of postoperative fatigue following minimally-invasive lumbar spine surgery

BACKGROUND

Postoperative fatigue is a distressing symptom and can have a major impact on the patient's quality of life after surgery. We investigate the extent of postoperative fatigue following minimally invasive spine surgery under general anesthesia (GA), and its impact on patients' quality of life (QOL) and activities of daily living (ADLs).

METHODS

We surveyed patients that underwent minimally-invasive lumbar spine surgery under GA within the previous year. A five-point Likert scale ("very much", "quite a bit", "somewhat", "a little bit", "not at all") was used to assess the extent of fatigue during the first postoperative month, its impact on QOL, and ADLs.

RESULTS

The survey was completed by 100 patients, 61% were male, mean age 64.6 ± 12.5 years, 31% underwent MIS-TLIF, 69% lumbar laminectomy. During the first postoperative month 45% of patients referred significant fatigue ("very much" or "quite a bit"); for 31% of patients fatigue significantly impacted their QOL; significantly limited their ADLs in 43% of patients. MIS-TLIF was associated with higher rate of postoperative fatigue compared to laminectomy (61.3% versus 37.7%, p = 0.02). Patients 65 years old or older had higher rates of fatigue compared to younger patients (55.6% versus 32.6%, p = 0.02). We did not observe a significant difference in postoperative fatigue between male and female patients.

CONCLUSIONS

Our study revealed a substantial incidence of postoperative fatigue in patients that underwent minimally-invasive lumbar spine surgery under GA, with a significant impact on QOL and ADLs. There is a need to research new strategies to reduce fatigue after spine surgery.

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.

Changes in the levels of IL-1β, cortisol and chromogranin A in saliva of subjects with occupational fatigue

Changes in the levels of interleukin-1β (IL-1β), cortisol and chromogranin A (CgA) in saliva of subjects with occupational fatigue were investigated. Doctors in the Emergency Department were selected as research subjects. Saliva was collected before work (after full rest) and after work (≥24 h). Electroencephalogram (EEG) was performed. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of IL-1β, cortisol and CgA in saliva. In order to obtain permission for human specimens, the study was approved by the Ethics Committee of the Affiliated Hospital of Hebei University of Engineering and registered for clinical trials (registration no. ChiC-TR-DCD-14005746). As there were only 4 subjects in this study without fatigue waves in EEG, and the number of these subjects was not sufficient to constitute a control group, the comparison of the contents of IL-1β, cortisol and CgA of all subjects before and after working for 18 h was just a confirmation of the statistical results of 43 cases with fatigue waves in the EEG. According to the results, there was no change in the contents of IL-1β and cortisol in the saliva of subjects with occupational fatigue before and after fatigue, whereas, there was a significant change in the content of CgA before and after fatigue. However, there was no correlation between the content of CgA and fatigue. The results of the present study revealed that IL-1β, cortisol and CgA indicators are not suitable diagnostic markers for occupational fatigue.

Fatigue in Inflammatory Bowel Diseases: Etiologies and Management

Fatigue is a burdensome, multidimensional, and multifactorial symptom that is associated with a wide array of chronic illnesses, specifically occurring in nearly 50% of patients with inflammatory bowel disease (IBD). Although common, given its subjective nature, physicians often under-recognize and undertreat this debilitating symptom. There are multiple etiologies that can contribute to fatigue in patients with IBD, including disease activity, anemia, medications, psychosomatic symptoms, and alterations to the gut–brain axis. The management of fatigue in IBD can be challenging, as it is often times multifaceted. In this review, we summarize the available tools for the diagnosis and measurement of fatigue, discuss etiologies, and make recommendations for their management. We identify knowledge gaps for the workup and treatment of fatigue and propose an algorithm to aid physicians in the evaluation and management of fatigue in this unique population. However, future research is needed to address several areas of knowledge deficits and improve the management of fatigue in IBD.

Anti-Fatigue Effects of the Unique Polysaccharide Marker of Dendrobium officinale on BALB/c Mice

Dendrobium officinale extract shows potent anti-fatigue effects; however, the active substance responsible for these effects remains undetermined. A glucomannan with a huge molecular size of 730 kDa, called DOP, was identified as the unique authentication marker of this expensive herb. DOP exhibited immunomodulating effects on macrophages and lymphocytes in our previous study. Clinical reports also showed that people with fatigue syndrome have a disturbed immune system. Because DOP is the unique and dominant component of D. officinale, we hypothesize that DOP may also have anti-fatigue activity. The present study aims to evaluate the anti-fatigue activity of DOP on BALB/c mice, with Rhodiola rosea extract as a positive control. DOP and Rhodiola rosea extract were orally administered at doses of 50 mg/kg and 100 mg/kg, respectively, for four weeks, and the anti-fatigue activity of DOP on BALB/c mice was evaluated using the weight-loaded swimming test. The contents of lactic dehydrogenase (LDH), creatine phosphokinase (CK), triglyceride (TG), blood urea nitrogen (BUN), superoxide dismutase (SOD), malondialdehyde (MDA), lactic acid (LD), and glutathione peroxidase (GSH-Px) in serum, glycogen of liver and gastrocnemius muscle were also determined. Their effects on variability of T cells and B cells were determined by using tetrazolium compound (MTS) method. The weight-loaded swimming exercise caused fatigue syndrome, mainly including the decreases of serum SOD/GSH-Px and gastrocnemius glycogen, as well as the increases of LDH, BUN, MDA, CK, TG, and LD in serum. All of these indicators of fatigue were inhibited to a certain extent by both DOP and Rhodiola rosea extract; however, the effects of DOP were much stronger than those of Rhodiola rosea extract. Compared to the positive control, mice dosed with DOP showed increases in endurance, body weight, and food intake. Furthermore, DOP-feeding mice significantly increased the cell variability of T lymphocytes and B lymphocytes, compared with that of mice in control group. This study indicates that the unique and dominant polysaccharide DOP of D. officinale has stronger anti-fatigue activity than Rhodiola rosea extract. As such, DOP has promising potential for pharmaceutical development into health products to reduce fatigue.

MicroRNAs hsa-miR-99b, hsa-miR-330, hsa-miR-126 and hsa-miR-30c: Potential Diagnostic Biomarkers in Natural Killer (NK) Cells of Patients with Chronic Fatigue Syndrome (CFS)/ Myalgic Encephalomyelitis (ME)

Background

Chronic Fatigue Syndrome (CFS/ME) is a complex multisystem disease of unknown aetiology which causes debilitating symptoms in up to 1% of the global population. Although a large cohort of genes have been shown to exhibit altered expression in CFS/ME patients, it is currently unknown whether microRNA (miRNA) molecules which regulate gene translation contribute to disease pathogenesis. We hypothesized that changes in microRNA expression in patient leukocytes contribute to CFS/ME pathology, and may therefore represent useful diagnostic biomarkers that can be detected in the peripheral blood of CFS/ME patients.

Methods

miRNA expression in peripheral blood mononuclear cells (PBMC) from CFS/ME patients and healthy controls was analysed using the Ambion Bioarray V1. miRNA demonstrating differential expression were validated by qRT-PCR and then replicated in fractionated blood leukocyte subsets from an independent patient cohort. The CFS/ME associated miRNA identified by these experiments were then transfected into primary NK cells and gene expression analyses conducted to identify their gene targets.

Results

Microarray analysis identified differential expression of 34 miRNA, all of which were up-regulated. Four of the 34 miRNA had confirmed expression changes by qRT-PCR. Fractionating PBMC samples by cell type from an independent patient cohort identified changes in miRNA expression in NK-cells, B-cells and monocytes with the most significant abnormalities occurring in NK cells. Transfecting primary NK cells with hsa-miR-99b or hsa-miR-330-3p, resulted in gene expression changes consistent with NK cell activation but diminished cytotoxicity, suggesting that defective NK cell function contributes to CFS/ME pathology.

Conclusion

This study demonstrates altered microRNA expression in the peripheral blood mononuclear cells of CFS/ME patients, which are potential diagnostic biomarkers. The greatest degree of miRNA deregulation was identified in NK cells with targets consistent with cellular activation and altered effector function.

Polymorphism in COMT is associated with IgG3 subclass level and susceptibility to infection in patients with chronic fatigue syndrome

BACKGROUND

Chronic fatigue syndrome (CFS) is considered as a neuroimmunological disease but the etiology and pathophysiology is poorly understood. Patients suffer from sustained exhaustion, cognitive impairment and an increased sensitivity to pain and sensory stimuli. A subset of patients has frequent respiratory tract infections (RRTI). Dysregulation of the sympathetic nervous system and an association with genetic variations in the catechol-O-methyltransferase (COMT) and glucocorticoid receptor genes influencing sympathetic and glucocorticoid metabolism were reported in CFS. Here, we analyzed the prevalence of SNPs of COMT and glucocorticoid receptor-associated genes in CFS patients and correlated them to immunoglobulin levels and susceptibility to RRTI.

METHODS

We analyzed blood cells of 74 CFS patients and 76 healthy controls for polymorphisms in COMT, FKBP5 and CRHR1 by allelic discrimination PCR. Serum immunoglobulins were determined by immunoturbidimetric technique, cortisol levels by ECLIA.

RESULTS

Contrary to previous reports, we found no difference between CFS patients and healthy controls in the prevalence of SNPs for COMT, FKBP5 and CRHR1. In patients with the Met/Met variant of COMT rs4680 we observed enhanced cortisol levels providing evidence for its functional relevance. Both enhanced IgE and diminished IgG3 levels and an increased susceptibility to RRTI were observed in CFS patients with the Met/Met variant. Such an association was not observed in 68 non-CFS patients with RRTI.

CONCLUSION

Our results indicate a relationship of COMT polymorphism rs4680 with immune dysregulation in CFS providing a potential link for the association between stress and infection susceptibility in CFS.

Use of single-nucleotide polymorphisms (SNPs) to distinguish gene expression subtypes of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)

AIMS

We have reported gene expression changes in patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and the fact that such gene expression data can be used to identify subtypes of CFS/ME with distinct clinical phenotypes. Due to the difficulties in using a comparative gene expression method as an aid to CFS/ME disease and subtype-specific diagnosis, we have attempted to develop such a method based on single-nucleotide polymorphism (SNP) analysis.

METHODS

To identify SNP allele associations with CFS/ME and CFS/ME subtypes, we tested genomic DNA of patients with CFS/ME (n=108), patients with endogenous depression (n=17) and normal blood donors (n=68) for 504 human SNP alleles located within 88 CFS-associated human genes using the SNP Genotyping GoldenGate Assay (Illumina, San Diego, California, USA). 360 ancestry informative markers (AIM) were also examined.

RESULTS

21 SNPs were significantly associated with CFS/ME compared with depression and normal groups. 148 SNP alleles had a significant association with one or more CFS/ME subtypes. For each subtype, associated SNPs tended to be grouped together within particular genes. AIM SNPs indicated that 4 subjects were of Asian origin while the remainder were Caucasian. Hierarchical clustering of AIM data revealed the relatedness between 2 couples of patients with CFS only and confirmed the overall heterogeneity of all subjects.

CONCLUSIONS

This study provides evidence that human SNPs located within CFS/ME associated genes are associated with particular genomic subtypes of CFS/ME. Further work is required to develop this into a clinically useful subtype-specific diagnostic test.

Mitochondrial dysfunctions in myalgic encephalomyelitis/chronic fatigue syndrome explained by activated immuno-inflammatory, oxidative and nitrosative stress pathways

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/cfs) is classified by the World Health Organization as a disorder of the central nervous system. ME/cfs is an neuro-immune disorder accompanied by chronic low-grade inflammation, increased levels of oxidative and nitrosative stress (O&NS), O&NS-mediated damage to fatty acids, DNA and proteins, autoimmune reactions directed against neoantigens and brain disorders. Mitochondrial dysfunctions have been found in ME/cfs, e.g. lowered ATP production, impaired oxidative phosphorylation and mitochondrial damage. This paper reviews the pathways that may explain mitochondrial dysfunctions in ME/cfs. Increased levels of pro-inflammatory cytokines, such as interleukin-1 and tumor necrosis factor-α, and elastase, and increased O&NS may inhibit mitochondrial respiration, decrease the activities of the electron transport chain and mitochondrial membrane potential, increase mitochondrial membrane permeability, interfere with ATP production and cause mitochondrial shutdown. The activated O&NS pathways may additionally lead to damage of mitochondrial DNA and membranes thus decreasing membrane fluidity. Lowered levels of antioxidants, zinc and coenzyme Q10, and ω3 polyunsaturated fatty acids in ME/cfs may further aggravate the activated immuno-inflammatory and O&NS pathways. Therefore, it may be concluded that immuno-inflammatory and O&NS pathways may play a role in the mitochondrial dysfunctions and consequently the bioenergetic abnormalities seen in patients with ME/cfs. Defects in ATP production and the electron transport complex, in turn, are associated with an elevated production of superoxide and hydrogen peroxide in mitochondria creating adaptive and synergistic damage. It is argued that mitochondrial dysfunctions, e.g. lowered ATP production, may play a role in the onset of ME/cfs symptoms, e.g. fatigue and post exertional malaise, and may explain in part the central metabolic abnormalities observed in ME/cfs, e.g. glucose hypometabolism and cerebral hypoperfusion.

Myalgic encephalomyelitis/chronic fatigue syndrome and encephalomyelitis disseminata/multiple sclerosis show remarkable levels of similarity in phenomenology and neuroimmune characteristics

BACKGROUND

'Encephalomyelitis disseminata' (multiple sclerosis) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are both classified as diseases of the central nervous system by the World Health Organization. This review aims to compare the phenomenological and neuroimmune characteristics of MS with those of ME/CFS.

DISCUSSION

There are remarkable phenomenological and neuroimmune overlaps between both disorders. Patients with ME/CFS and MS both experience severe levels of disabling fatigue and a worsening of symptoms following exercise and resort to energy conservation strategies in an attempt to meet the energy demands of day-to-day living. Debilitating autonomic symptoms, diminished cardiac responses to exercise, orthostatic intolerance and postural hypotension are experienced by patients with both illnesses. Both disorders show a relapsing-remitting or progressive course, while infections and psychosocial stress play a large part in worsening of fatigue symptoms. Activated immunoinflammatory, oxidative and nitrosative (O+NS) pathways and autoimmunity occur in both illnesses. The consequences of O+NS damage to self-epitopes is evidenced by the almost bewildering and almost identical array of autoantibodies formed against damaged epitopes seen in both illnesses. Mitochondrial dysfunctions, including lowered levels of ATP, decreased phosphocreatine synthesis and impaired oxidative phosphorylation, are heavily involved in the pathophysiology of both MS and ME/CFS. The findings produced by neuroimaging techniques are quite similar in both illnesses and show decreased cerebral blood flow, atrophy, gray matter reduction, white matter hyperintensities, increased cerebral lactate and choline signaling and lowered acetyl-aspartate levels.

SUMMARY

This review shows that there are neuroimmune similarities between MS and ME/CFS. This further substantiates the view that ME/CFS is a neuroimmune illness and that patients with MS are immunologically primed to develop symptoms of ME/CFS.

Chronic fatigue syndrome/myalgic encephalomyelitis: an update

Chronic Fatigue Syndrome (CFS), also referred to as Myalgic Encephalomyelitis (ME), is a disease of unknown origin. It is classified as Post Viral Fatigue Syndrome (PVFS) in the WHO International Classification of Diseases (ICD) and listed as sub-category at G93.3 under chapter G93, other disorders of the brain. ME/CFS is primarily an endemic disorder but occurs in both epidemic and sporadic forms. It affects all racial-ethnic groups and is seen in all socioeconomic strata. A diagnosis of CFS is a diagnosis of exclusion, meaning other medical conditions, including psychiatric disorders, must be first ruled out. CFS is diagnosed if there is no other explanation for the fatigue and if the other symptoms did not develop before the fatigue. The estimated worldwide prevalence of CFS is 0.4?1 percent. The disease predominantly affects young adults, with a peak age of onset of between 20 and 40 years, and women, with a female to male ratio of 6:1. Mean illness duration ranges from 3 to 9 years. The patho-physiological mechanism of CFS is unclear but the immunological pattern of CFS patients gleaned from various studies indicates that the immune system is chronically activated. Besides the role of environmental insults (xenobiotics, infectious agents, stress) the genetic features of patients are studied to evaluate their role in triggering the pathology. At present there are no specific pharmacological therapies to treat the disease but a variety of therapeutic approaches have been described as benefiting patients. Treatment programs are directed at relief of symptoms, with the goal of the patient regaining some level of preexisting function and well-being.

Counseling African Americans in Cardiac Rehabilitation: Implications for Comprehensive Lifestyle Modification

African Americans are more likely to die of a myocardial infarction than any other racial group and have higher rates of sudden cardiac death, and in comparison to whites, these deaths are likely to occur at a younger age. Because secondary prevention interventions have been reported to reduce overall mortality, it is important that health care providers understand and respond with sensitivity to the needs and preferences that African Americans bring to cardiac rehabilitation. Providing culturally appropriate cardiac rehabilitation services to African Americans has the potential to improve access to care, quality of care, and health outcomes. This article reviews the historical legacy and general values and beliefs that African Americans bring to their participation in cardiac rehabilitation and examines values and beliefs about diet, weight, body image, exercise, rest, and preferences for depression treatment that should be considered when counseling African Americans. Social-ecological factors that influence the ability to commit to and maintain cardiovascular risk—reducing behaviors are also discussed. Strategies for responding to the health-related beliefs and cultural values of African Americans are examined.

Microbial infections in eight genomic subtypes of chronic fatigue syndrome/myalgic encephalomyelitis

BACKGROUND

The authors have previously reported genomic subtypes of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) based on expression of 88 human genes.

AIM

To attempt to reproduce these findings, determine the specificity of this signature to CFS/ME, and test for associations between CFS/ME subtype and infection.

METHODS

Expression levels of 88 human genes were determined in blood of 62 new patients with idiopathic CFS/ME (according to Fukuda criteria), six patients with Q-fever-associated CFS/ME from the Birmingham Q-fever outbreak (according to Fukuda criteria), 14 patients with endogenous depression (according to DSM-IV criteria) and 29 normal blood donors.

RESULTS

In patients with CFS/ME, differential expression was confirmed for all 88 genes. Q-CFS/ME had similar patterns of gene expression to idiopathic CFS/ME. Gene expression in patients with endogenous depression was similar to that in the normal controls, except for upregulation of five genes (APP, CREBBP, GNAS, PDCD2 and PDCD6). Clustering of combined gene data in CFS/ME patients for this and the authors' previous study (117 CFS/ME patients) revealed genomic subtypes with distinct differences in SF36 scores, clinical phenotypes, severity and geographical distribution. Antibody testing for Epstein-Barr virus, enterovirus, Coxiella burnetii and parvovirus B19 revealed evidence of subtype-specific relationships for Epstein-Barr virus and enterovirus, the two most common infectious triggers of CFS/ME.

CONCLUSIONS

This study confirms the involvement of these genes in CFS/ME.

Antibody to parvovirus B19 nonstructural protein is associated with chronic arthralgia in patients with chronic fatigue syndrome/myalgic encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a neuro-immune disease of uncertain pathogenesis. Human parvovirus B19 infection has been shown to occur just prior to development of the onset of CFS/ME in several cases, although B19 seroprevalence studies do not show any significant differences between CFS/ME and controls. In this study, we analysed parvovirus B19 markers in CFS/ME patients (n=200), diagnosed according to Fukuda CDC criteria, and normal blood donors (n=200). Serum from each subject was tested for anti-B19 VP2 IgM and IgG (by Biotrin ELISA), anti-B19 NS1 IgM and IgG (by immunofluorescence), and B19 DNA (by real-time PCR). CFS/ME patients and normal blood donors had a similar B19 seroprevalence (75 % versus 78 %, respectively). Eighty-three CFS patients (41.5 %) as compared with fourteen (7 %) normal blood donors tested positive for anti-B19 NS1 IgG (chi(2)=64.8; P<0.0001; odds ratio=9.42, CI 5.11-17.38). Of these 83 patients, 61 complained of chronic joint pain, while 22 did not. Parvovirus B19 DNA was detected in serum of 11 CFS patients and none of the controls by Taqman real-time PCR (chi(2)=9.35, P<0.002). Positivity for anti-B19 NS1 IgG was associated with higher expression levels of the human CFS-associated genes NHLH1 and GABPA. As NS1 antibodies are thought to indicate chronic or severe courses of B19 infection, these findings suggest that although the seroprevalence of B19 in CFS patients is similar to controls, the immune control of the virus in these patients may not be efficient.

Hypothalamic involvement assessed by T1 relaxation time in patients with relapsing—remitting multiple sclerosis

Recent work in multiple sclerosis, focusing on neuropathological abnormalities, found a frequent and severe hypothalamic involvement. The possible clinical implications are disturbances in sleep and sexual activity, depression, memory impairment and fatigue. Despite this there are no magnetic resonance imaging studies focusing on in vivo hypothalamic pathology in multiple sclerosis. Our objective was to investigate magnetic resonance imaging-detectable abnormalities related to pathological changes in the hypothalamus of patients with multiple sclerosis, and to subsequently explore the relationship with fatigue. We used T1 relaxation time as a sensitive measure of pathology. Using region of interest analysis, median T1 values in the hypothalamus were measured in 44 relapsing—remitting multiple sclerosis patients and in 13 healthy controls. Fatigue was assessed using the Fatigue Severity Scale, and patients were divided in two subgroups, fatigued and non-fatigued, according to Fatigue Severity Scale scores. We found a significantly higher T1 relaxation time in the hypothalamus of multiple sclerosis patients compared with controls ( p = 0.027). There was a significant correlation between T1 values and fatigue severity (rho 0.437, p = 0.008), and median T1 values were different among the study groups. Our results show that pathological involvement of the hypothalamus in relapsing—remitting multiple sclerosis is detectable using magnetic resonance imaging, and that the pathology measured by quantitative T1 might reflect fatigue.

Gene profiling of patients with chronic fatigue syndrome/myalgic encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a multisystem disease, the pathogenesis of which remains undetermined. Following two microarray studies, we reported the differential expression of 88 human genes in patients with CFS; 85 of these genes were upregulated and 3 were downregulated. The top functional categories of these 88 genes were hematologic disease and function, immunologic disease and function, cancer, cell death, immune response, and infection. Clustering of quantitative polymerase chain reaction data from CFS/ME patients revealed seven subtypes with distinct differences in Short Form (SF)-36 scores, clinical phenotypes, and severity. Gene signatures in each subtype implicate five human genes as possible targets for specific therapy. Development of a diagnostic test for subtype status is now a priority. The possibility that these subtypes represent individual host responses to particular microbial infections is being investigated and may provide another route to specific therapies for CFS patients.

Diagnostic and treatment challenges of chronic fatigue syndrome: role of immediate-release methylphenidate

Chronic fatigue syndrome (CFS) is a distinct entity belonging to the group of persistent fatigue that can be challenging to diagnose and to treat. It is characterized by a combination of prolonged fatigue, other nonspecific somatic manifestations and neuropsychological symptoms, including difficulties with concentration, short-term memory and thinking, as well as impaired attention and slowed processing speed. Neurostimulants increasing dopamine and norepinephrine activity, such as bupropion, dextroamphetamine and recently immediate-release methylphenidate have been advocated to improve neurocognitive deficits. The use of immediate-release methylphenidate in CFS has been shown in one small study. Using the positive results of this study and the well-known beneficial effects of the drug on a range of similar cognitive symptoms in attention-deficit/hyperactivity disorder, this perspective addresses CFS and other related disorders and provides a discussion on the potential promising role of methylphenidate in the therapeutic armamentarium of CFS.

Gene expression subtypes in patients with chronic fatigue syndrome/myalgic encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a multisystem disease, the pathogenesis of which remains undetermined. We set out to determine the precise abnormalities of gene expression in the blood of patients with CFS/ME. We analyzed gene expression in peripheral blood from 25 patients with CFS/ME diagnosed according to the Centers for Disease Control and Prevention diagnostic criteria and 50 healthy blood donors, using a microarray with a cutoff fold difference of expression of >or=2.5. Genes showing differential expression were further analyzed in 55 patients with CFS/ME and 75 healthy blood donors, using quantitative polymerase chain reaction. Differential expression was confirmed for 88 genes; 85 were upregulated, and 3 were downregulated. Highly represented functions were hematological disease and function, immunological disease and function, cancer, cell death, immune response, and infection. Clustering of quantitative polymerase chain reaction data from patients with CFS/ME revealed 7 subtypes with distinct differences in Medical Outcomes Survey Short Form-36 scores, clinical phenotypes, and severity.

Open-label study of s-citalopram therapy of chronic fatigue syndrome and co-morbid major depressive disorder

OBJECTIVE

Chronic fatigue syndrome (CFS) is a debilitating disorder with prominent symptoms of malaise, fatigue, myalgia, arthralgia, and impaired concentration. The symptoms of CFS may often overlap those of Major Depressive Disorder (MDD). Treatment of CFS has generally been disappointing. We hypothesized that s-citalopram therapy may improve the symptoms of both disorders in CFS patients with co-morbid depression.

METHODS

16 patients received s-citalopram 10 mg to 20 mg daily for up to 12 weeks. Outcome measures of CFS included the Chalder Fatigue Questionnaire (CFQ), the multi-dimensional Fatigue Impact Scale (FIS), the CFS symptom rating (CFS-SR) 100 mm visual analogue scale, and the clinical global impressions severity (CGI/S) and change (CGI/C) ratings. Secondary outcomes of MDD included the Hamilton Depression Rating (HAM-D), Beck Depression Inventory (BDI), and the CGI/S and CGI/C ratings of MDD.

RESULTS

We observed reductions in the mean CFQ score (p<0.0005), FIS score (p<0.0005), and CGI/S (p<0.0005) and CGI/C (p<0.0005) ratings over time. There was a significant improvement in 5 of the 8 CFS-SR symptoms: post-exertion malaise (p=0.001), headaches (p<0.0005), un-refreshing sleep (p<0.0005), and impaired memory and concentration (p<0.0005). There was also a reduction in mean HAM-D (p<0.0005), BDI (p<0.0005), CGI/S (p=0.001) and CGI/C (p<0.0005) ratings of MDD.

LIMITATIONS

The sample size was limited and the study design was not double-blind or placebo controlled.

CONCLUSION

We observed a significant reduction in both CFS and co-morbid MDD symptom severity ratings, and improvement in 5 of 8 core somatic symptoms of CFS during s-citalopram therapy.

Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is thought to have a worldwide prevalence of 0.4-1% with approximately 240,000 patients in the UK. Diagnosis is based on clinical criteria and critically depends on exclusion of other physical and psychiatric diseases. Studies of pathogenesis have revealed immune system abnormalities and chronic immune activation, dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, brain abnormalities, evidence of emotional stress (comprising host aspects) and evidence of exogenous insults, for example, various microbial infections (Epstein-Barr virus, enteroviruses, parvovirus B19, Coxiella burnetii and Chlamydia pneumoniae), vaccinations and exposure to organophosphate chemicals and other toxins (comprising environmental aspects). Emotional stress appears to be very important as it reduces the ability of the immune system to clear infections, it's presence has been shown to determine whether or not an individual develops symptoms upon virus infection, and it leads to activation of the HPA axis. But, emotional stress is distinct from depression, the presence of which precludes a diagnosis of CFS. There is no specific treatment for CFS other than the much underutilised approach of specific treatment of virus infections. Current priorities are to understand the molecular pathogenesis of disease in terms of human and virus gene expression, to develop a diagnostic test based on protein biomarkers, and to develop specific curative treatments.

Chronic fatigue, unrefreshing sleep and nocturnal polysomnography

BACKGROUND AND PURPOSE

To investigate the complaint of unrefreshing sleep with study of sleep electroencephalogram (EEG) in patients with chronic fatigue.

PATIENTS AND METHODS

Fourteen successively seen patients (mean age: 41.1 9.8) who complained of chronic fatigue but denied sleepiness and agreed to participate were compared to 14 controls (33.6+/-10.2 years) who were monitored during sleep recorded in parallel. After performing conventional sleep scoring we applied Fast Fourier Transformation (FFT) for the delta 1, delta 2, theta, alpha, sigma 1, sigma 2, beta EEG frequency bands. The presence of non-rapid eye movement (NREM) sleep instability was studied with calculation of cyclic alternating pattern (CAP) rate. Two-way analysis of variance (ANOVA) was performed to analyze FFT results and Mann-Whitney U-test to compare CAP rate in both groups of subjects.

RESULTS

Slow wave sleep (SWS) percentage and sleep efficiency were lower, but there was a significant increase in delta 1 (slow delta) relative power in the chronic fatigue group when compared to normals (P<0.01). All the other frequency bands were proportionally and significantly decreased compared to controls. CAP rate was also significantly greater in subjects with chronic fatigue than in normals (P=0.04). An increase in respiratory effort and nasal flow limitation were noted with chronic fatigue.

CONCLUSIONS

The complaints of chronic fatigue and unrefreshing sleep were associated with an abnormal CAP rate, with increase in slow delta power spectrum, affirming the presence of an abnormal sleep progression and NREM sleep instability. These specific patterns were related to subtle, undiagnosed sleep-disordered breathing.

Burnout and risk of cardiovascular disease: evidence, possible causal paths, and promising research directions

Burnout is characterized by emotional exhaustion, physical fatigue, and cognitive weariness, resulting from prolonged exposure to work-related stress. The authors review the accumulated evidence suggesting that burnout and the related concept of vital exhaustion are associated with increased risk of cardiovascular disease and cardiovascular-related events. The authors present evidence supporting several potential mechanisms linking burnout with ill health, including the metabolic syndrome, dysregulation of the hypothalamic-pituitary-adrenal axis along with sympathetic nervous system activation, sleep disturbances, systemic inflammation, impaired immunity functions, blood coagulation and fibrinolysis, and poor health behaviors. The association of burnout and vital exhaustion with these disease mediators suggests that their impact on health may be more extensive than currently indicated.

The debate: myalgic encephalomyelitis and chronic fatigue syndrome

Almost every aspect of myalgic encephalomyelitis (or encephalopathy) and chronic fatigue syndrome is the subject of disagreement and uncertainty -- something that has undoubtedly hampered recognition, understanding and research. Although the pathogenesis remains the subject of intense medical debate, a number of predisposing, precipitating and perpetuating factors are now starting to emerge. Therapeutic nihilism is no longer appropriate as there is a great deal that can be done to alleviate some of the more distressing symptoms and improve quality of life for these patients.

Identifying illness parameters in fatiguing syndromes using classical projection methods

OBJECTIVES

To examine the potential of multivariate projection methods in identifying common patterns of change in clinical and gene expression data that capture the illness state of subjects with unexplained fatigue and nonfatigued control participants.

METHODS

Data for 111 female subjects was examined. A total of 59 indicators, including multidimensional fatigue inventory (MFI), medical outcome Short Form 36 (SF-36), Centers for Disease Control and Prevention (CDC) symptom inventory and cognitive response described illness. Partial least squares (PLS) was used to construct two feature spaces: one describing the symptom space from gene expression in peripheral blood mononuclear cells (PBMC) and one based on 117 clinical variables. Multiplicative scatter correction followed by quantile normalization was applied for trend removal and range adjustment of microarray data. Microarray quality was assessed using mean Pearson correlation between samples. Benjamini-Hochberg multiple testing criteria served to identify significantly expressed probes.

RESULTS

A single common trend in 59 symptom constructs isolates of nonfatigued subjects from the overall group. This segregation is supported by two co-regulation patterns representing 10% of the overall microarray variation. Of the 39 principal contributors, the 17 probes annotated related to basic cellular processes involved in cell signaling, ion transport and immune system function. The single most influential gene was sestrin 1 (SESN1), supporting recent evidence of oxidative stress involvement in chronic fatigue syndrome (CFS). Dominant variables in the clinical feature space described heart rate variability (HRV) during sleep. Potassium and free thyroxine (T4) also figure prominently.

CONCLUSION

Combining multiple symptom, gene or clinical variables into composite features provides better discrimination of the illness state than even the most influential variable used alone. Although the exact mechanism is unclear, results suggest a common link between oxidative stress, immune system dysfunction and potassium imbalance in CFS patients leading to impaired sympatho-vagal balance strongly reflected in abnormal HRV.

Trichopus zeylanicus combats fatigue without amphetamine-mimetic activity

Chronic fatigue is a complex and little understood symptom for which there is no safe and effective pharmacotherapy. The present study was conducted to investigate the effectiveness of Trichopus zeylanicus whole plant powder on fatigue in young Sprague Dawley rats, and aged normal and long-living mutant Ames dwarf mice. Fatigue was evaluated by subjecting the animals to a forced swim test. Trichopus zeylanicus (250 and 500 mg/kg) treated young Sprague-Dawley rats resisted fatigue at a significant level (p < 0.005) compared with controls by an extended swim time in the forced swim test. Oral Trichopus zeylanicus (500 mg/kg) treatment for 2 weeks significantly increased the mobility time in the aged mutant (p < 0.05) and normal mice (p < 0.01) and significantly increased the swim time in the forced swim test in the aged normal mice (p < 0.05). Amphetamine-mimetic activity in Trichopus zeylanicus was excluded by suitable tests. These results show that Trichopus zeylanicus whole plant powder has anti-fatigue effects in young Sprague-Dawley rats and aged normal and mutant Ames dwarf mice providing scientific evidence for the Kani tribal practice in India.

Botanical therapies in chronic fatigue

Chronic fatigue often occurs in aging and in various neurological, psychiatric and systemic diseases. The available therapies in modern medicine are limited. The exploration of potential alternative therapies from traditional medicine is reviewed, as there are several botanicals with experimental evidence of efficacy based on animal models and clinical studies.

Antioxidant and DNA protecting properties of anti-fatigue herb Trichopus zeylanicus

Chronic fatigue is considered a complex symptom for which currently there is no curative treatment available. Oxidative stress plays an important role in the etiology of fatigue and antioxidant treatment might be a valuable therapeutic approach. The Kani, a tribal high altitude living population in southern India, traditionally use the seeds of Trichopus zeylanicus to combat fatigue. In this study, the antioxidant properties of Trichopus zeylanicus were established on free radicals (DPPH and ABTS), its ability to reduce iron, lipoxygenase activity and hydrogen peroxide-induced lipid peroxidation. The effects of Trichopus zeylanicus on reactive oxygen species induced plasmid DNA (pBR322) cleavage were also investigated. Trichopus zeylanicus significantly scavenged free radicals, reduced lipid peroxidation and inhibited lipoxygenase activity. Trichopus zeylanicus also exhibited iron-chelating activity and inhibited reactive oxygen species induced DNA damage. Trichopus zeylanicus contains NADH, polyphenols and sulfhydryl compounds, which have the ability to scavenge reactive oxygen species suggesting that the antioxidant activity may be an important mechanism of action of Trichopus zeylanicus to combat fatigue.

Fatigue in multiple sclerosis: an example of cytokine mediated sickness behaviour?

BACKGROUND

Fatigue is a major complaint of multiple sclerosis (MS) patients. However, little is known about its pathophysiological mechanisms. Evidence from chronic fatigue syndrome and studies on sickness behaviour suggest that immune and neuroendocrine factors may play a causative role in the development of fatigue.

METHODS

We compared whole blood stimulatory capacity for pro- (TNFalpha, IFNgamma) and anti-inflammatory cytokines (IL-10) as well as hypothalamo-pituitary-adrenal (HPA) axis function in 15 MS patients with marked fatigue and 15 patients without fatigue as determined by the Fatigue Severity Scale (FSS).

RESULTS

Proinflammatory cytokines were significantly higher (TNFalpha: 478.9 v 228.2 pg/ml, p = 0.01; IFNgamma: 57.6 v 27.8 pg/ml; p = 0.01) in MS patients with fatigue. Furthermore, TNFalpha values significantly correlated with daytime sleepiness as measured by the Epworth Sleepiness Scale (r = 0.64, p = 0.001). Controlling for disease activity (as measured by the Cambridge Multiple Sclerosis Basic Score), disease duration, Expanded Disability Status Scale, and depression further increased the correlation of cytokine production and fatigue. HPA axis activity was not related to fatigue but was modestly correlated with cognitive impairment.

CONCLUSION

Our data suggest that fatigue in MS is at least partially mediated through activation of proinflammatory cytokines. In line with earlier findings, HPA axis dysfunction seems not to be relevant in MS fatigue pathogenesis but appears to be linked to cognitive impairment. Our findings suggest that increased levels of inflammatory cytokines may be involved in MS fatigue. Investigation of cytokine profiles may increase the understanding of fatigue pathogenesis in MS.

Exercise responsive genes measured in peripheral blood of women with chronic fatigue syndrome and matched control subjects

Background

Chronic fatigue syndrome (CFS) is defined by debilitating fatigue that is exacerbated by physical or mental exertion. To search for markers of CFS-associated post-exertional fatigue, we measured peripheral blood gene expression profiles of women with CFS and matched controls before and after exercise challenge.

Results

Women with CFS and healthy, age-matched, sedentary controls were exercised on a stationary bicycle at 70% of their predicted maximum workload. Blood was obtained before and after the challenge, total RNA was extracted from mononuclear cells, and signal intensity of the labeled cDNA hybridized to a 3800-gene oligonucleotide microarray was measured. We identified differences in gene expression among and between subject groups before and after exercise challenge and evaluated differences in terms of Gene Ontology categories.

Exercise-responsive genes differed between CFS patients and controls. These were in genes classified in chromatin and nucleosome assembly, cytoplasmic vesicles, membrane transport, and G protein-coupled receptor ontologies. Differences in ion transport and ion channel activity were evident at baseline and were exaggerated after exercise, as evidenced by greater numbers of differentially expressed genes in these molecular functions.

Conclusion

These results highlight the potential use of an exercise challenge combined with microarray gene expression analysis in identifying gene ontologies associated with CFS.