Mechanisms Explaining Muscle Fatigue and Muscle Pain in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): a Review of Recent Findings

Abstract:

PURPOSE OF REVIEW: Here, we review potential causes of muscle dysfunction seen in many patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) such as the effects of oxidative and nitrosative stress (O&NS) and mitochondrial impairments together with reduced heat shock protein production and a range of metabolic abnormalities.

RECENT FINDINGS: Several studies published in the last few years have highlighted the existence of chronic O&NS, inflammation, impaired mitochondrial function and reduced heat shock protein production in many patients with ME/CFS. These studies have also highlighted the detrimental effects of chronically elevated O&NS on muscle functions such as reducing the time to muscle fatigue during exercise and impairing muscle contractility.

Mechanisms have also been revealed by which chronic O&NS and or impaired heat shock production may impair muscle repair following exercise and indeed the adaptive responses in the striated muscle to acute and chronic increases in physical activity. The presence of chronic O&NS, low-grade inflammation and impaired heat shock protein production may well explain the objective findings of increased muscle fatigue, impaired contractility and multiple dimensions of exercise intolerance in many patients with ME/CFS.

 

Source: Gerwyn M, Maes M. Mechanisms Explaining Muscle Fatigue and Muscle Pain in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): a Review of Recent Findings. Curr Rheumatol Rep. 2017 Jan;19(1):1. doi: 10.1007/s11926-017-0628-x. https://www.ncbi.nlm.nih.gov/pubmed/28116577

 

A systematic review of the association between fatigue and genetic polymorphisms

Abstract:

Fatigue is one of the most common and distressing symptoms, leading to markedly decreased quality of life among a large subset of patients with a variety of disorders. Susceptibility to fatigue may be influenced by genetic factors including single nucleotide polymorphisms (SNPs), especially in the regulatory regions, of relevant genes.

To further investigate the association of SNPs with fatigue in various patient populations, a systematic search was conducted on Pubmed, CINAHL, PsycINFO, and Sociological Abstracts Database for fatigue related-terms in combination with polymorphisms or genetic variation-related terms. Fifty papers in total met the inclusion and exclusion criteria for this analysis. These 50 papers were further classified into three subgroups for evaluation: chronic fatigue syndrome (CFS), cancer-related fatigue (CRF) and other disease-related fatigue.

SNPs in regulatory pathways of immune and neurotransmitter systems were found to play important roles in the etiologies of CFS, CRF and other disease-related fatigue. Evidence for associations between elevated fatigue and specific polymorphisms in TNFα, IL1b, IL4 and IL6 genes was revealed for all three subgroups of fatigue.

We also found CFS shared a series of polymorphisms in HLA, IFN-γ, 5-HT and NR3C1 genes with other disease-related fatigue, however these SNPs (excluding IFN-γ) were not found to be adequately investigated in CRF. Gaps in knowledge related to fatigue etiology and recommendations for future research are further discussed.

Copyright © 2017 Elsevier Inc. All rights reserved.

 

Source: Wang T, Yin J, Miller AH, Xiao C. A systematic review of the association between fatigue and genetic polymorphisms. Brain Behav Immun. 2017 Jan 12. pii: S0889-1591(17)30007-7. doi: 10.1016/j.bbi.2017.01.007. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/28089639

 

Children’s experiences of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review and meta-ethnography of qualitative studies

Abstract:

OBJECTIVE: To synthesis the qualitative studies of children’s experiences of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME).

DESIGN: Systematic review and meta-ethnography.

BACKGROUND: CFS/ME is an important disabling illness, with uncertain cause and prognosis. As a result, children with CFS/ME can find themselves living with greater uncertainty and stigma, exacerbating the impact of the condition. There is a growing body of qualitative research in CFS/ME, yet there has been no attempt to systematically synthesis the studies involving children.

METHODS: Studies exploring the experiences of children diagnosed with CFS/ME, published or unpublished, using qualitative methods were eligible. MEDLINE, EMBASE, PsycINFO and CINAHL databases were searched as well as grey literature, reference lists and contacting authors. Quality assessment was done independently using the Critical Appraisal Skills Programme (CASP) checklist. Studies were synthesised using techniques of meta-ethnography.

RESULTS: Ten studies involving 82 children with CFS/ME aged 8-18 were included. Our synthesis describes four third-order constructs within children’s experiences: (1) disruption and loss: physical, social and the self; (2) barriers to coping: suspension in uncertainty, problems with diagnosis and disbelief; (3) facilitators to coping: reducing uncertainty, credible illness narratives, diagnosis and supportive relationships and (4) hope, personal growth and recovery. CFS/ME introduces profound biographical disruption through its effects on children’s ability to socialise, perform school and therefore how they see their future. Unfamiliarity of the condition, problems with diagnosis and felt stigma prevent children from forming a new illness identity. Children adopt coping strategies such as building credible explanations for their illness.

CONCLUSIONS: Physical, social, emotional and self-dimensions of life should be included when treating and measuring outcomes from healthcare in paediatric CFS/ME. There is a need for greater recognition and diagnosis of childhood CFS/ME, specialist advice on activity management and improved communication between health and education providers to help children cope with their condition.

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

 

Source: Parslow RM, Harris S, Broughton J, Alattas A, Crawley E, Haywood K, Shaw A. Children’s experiences of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review and meta-ethnography of qualitative studies. BMJ Open. 2017 Jan 13;7(1):e012633. doi: 10.1136/bmjopen-2016-012633. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5253584/ (Full article)

 

Mortality in Patients with Myalgic Encephalomyelitis and Chronic Fatigue Syndrome

Abstract:

BACKGROUND: There is a dearth of research examining mortality in individuals with myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Some studies suggest there is an elevated risk of suicide and earlier mortality compared to national norms. However, findings are inconsistent as other researchers have not found significant increases in all-cause mortality for patients.

OBJECTIVE: This study sought to determine if patients with ME or CFS are reportedly dying earlier than the overall population from the same cause.

METHODS: Family, friends, and caregivers of deceased individuals with ME or CFS were recruited through social media, patient newsletters, emails, and advocate websites. This study analyzed data including cause and age of death for 56 individuals identified as having ME or CFS.

RESULTS: The findings suggest patients in this sample are at a significantly increased risk of earlier all-cause (M = 55.9 years) and cardiovascular-related (M = 58.8 years) mortality, and they had a directionally lower mean age of death for suicide (M = 41.3 years) and cancer (M =66.3 years) compared to the overall U.S. population [M = 73.5 (all-cause), 77.7 (cardiovascular), 47.4 (suicide), and 71.1 (cancer) years of age].

CONCLUSIONS: The results suggest there is an increase in risk for earlier mortality in patients with ME and CFS. Due to the small sample size and over-representation of severely ill patients, the findings should be replicated to determine if the directional differences for suicide and cancer mortality are significantly different from the overall U.S. population.

 

Source: McManimen SL, Devendorf AR, Brown AA, Moore BC, Moore JH, Jason LA. Mortality in Patients with Myalgic Encephalomyelitis and Chronic Fatigue Syndrome. Fatigue. 2016;4(4):195-207. doi: 10.1080/21641846.2016.1236588. Epub 2016 Oct 12. https://www.ncbi.nlm.nih.gov/pubmed/28070451

 

Identifying Key Symptoms Differentiating Myalgic Encephalomyelitis and Chronic Fatigue Syndrome from Multiple Sclerosis

Abstract:

It is unclear what key symptoms differentiate Myalgic Encephalomyelitis (ME) and Chronic Fatigue syndrome (CFS) from Multiple Sclerosis (MS). The current study compared self-report symptom data of patients with ME or CFS with those with MS. The self-report data is from the DePaul Symptom Questionnaire, and participants were recruited to take the questionnaire online.

Data were analyzed using a machine learning technique called decision trees. Five symptoms best differentiated the groups. The best discriminating symptoms were from the immune domain (i.e., flu-like symptoms and tender lymph nodes), and the trees correctly categorized MS from ME or CFS 81.2% of the time, with those with ME or CFS having more severe symptoms. Our findings support the use of machine learning to further explore the unique nature of these different chronic diseases

 

Source: Ohanian D, Brown A, Sunnquist M, Furst J, Nicholson L, Klebek L, Jason LA. Identifying Key Symptoms Differentiating Myalgic Encephalomyelitis and Chronic Fatigue Syndrome from Multiple Sclerosis. Neurology (ECronicon). 2016;4(2):41-45. Epub 2016 Dec 19. https://www.ncbi.nlm.nih.gov/pubmed/28066845

 

Metabolic profiling of a myalgic encephalomyelitis/chronic fatigue syndrome discovery cohort reveals disturbances in fatty acid and lipid metabolism

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) remains a continuum spectrum disease without biomarkers or simple objective tests, and therefore relies on a diagnosis from a set of symptoms to link the assortment of brain and body disorders to ME/CFS. Although recent studies show various affected pathways, the underlying basis of ME/CFS has yet to be established.

In this pilot study, we compare plasma metabolic signatures in a discovery cohort, 17 patients and 15 matched controls, and explore potential metabolic perturbations as the aftermath of the complex interactions between genes, transcripts and proteins.

This approach to examine the complex array of symptoms and underlying foundation of ME/CFS revealed 74 differentially accumulating metabolites, out of 361 (P < 0.05), and 35 significantly altered after statistical correction (Q < 0.15). The latter list includes several essential energy-related compounds which could theoretically be linked to the general lack of energy observed in ME/CFS patients. Pathway analysis points to a few pathways with high impact and therefore potential disturbances in patients, mainly taurine metabolism and glycerophospholipid metabolism, combined with primary bile acid metabolism, as well as glyoxylate and dicarboxylate metabolism and a few other pathways, all involved broadly in fatty acid metabolism.

Purines, including ADP and ATP, pyrimidines and several amino acid metabolic pathways were found to be significantly disturbed. Finally, glucose and oxaloacetate were two main metabolites affected that have a major effect on sugar and energy levels. Our work provides a prospective path for diagnosis and understanding of the underlying mechanisms of ME/CFS.

 

Source: Germain A, Ruppert D, Levine SM, Hanson MR. Metabolic profiling of a myalgic encephalomyelitis/chronic fatigue syndrome discovery cohort reveals disturbances in fatty acid and lipid metabolism. Mol Biosyst. 2017 Jan 31;13(2):371-379. doi: 10.1039/c6mb00600k. https://www.ncbi.nlm.nih.gov/pubmed/28059425

 

Treatment and management of chronic fatigue syndrome/myalgic encephalomyelitis: all roads lead to Rome

Abstract:

This review explores the current evidence on benefits and harms of therapeutic interventions in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and makes recommendations. CFS/ME is a complex, multi-system, chronic medical condition whose pathophysiology remains unknown. No established diagnostic tests exist nor are any FDA-approved drugs available for treatment. Because of the range of symptoms of CFS/ME, treatment approaches vary widely.

Studies undertaken have heterogeneous designs and are limited by sample size, length of follow-up, applicability and methodological quality. The use of rintatolimod and rituximab as well as counselling, behavioural and rehabilitation therapy programs may be of benefit for CFS/ME, but the evidence of their effectiveness is still limited. Similarly, adaptive pacing appears to offer some benefits, but the results are debatable: so is the use of nutritional supplements, which may be of value to CFS/ME patients with biochemically proven deficiencies.

To summarize, the recommended treatment strategies should include proper administration of nutritional supplements in CFS/ME patients with demonstrated deficiencies and personalized pacing programs to relieve symptoms and improve performance of daily activities, but a larger randomized controlled trial (RCT) evaluation is required to confirm these preliminary observations.

At present, no firm conclusions can be drawn because the few RCTs undertaken to date have been small-scale, with a high risk of bias, and have used different case definitions. Further, RCTs are now urgently needed with rigorous experimental designs and appropriate data analysis, focusing particularly on the comparison of outcomes measures according to clinical presentation, patient characteristics, case criteria and degree of disability (i.e. severely ill ME cases or bedridden).

© 2017 The British Pharmacological Society.

 

Source: Castro-Marrero J, Sáez-Francàs N, Santillo D, Alegre J. Treatment and management of chronic fatigue syndrome/myalgic encephalomyelitis: all roads lead to Rome. Br J Pharmacol. 2017 Mar;174(5):345-369. doi: 10.1111/bph.13702. Epub 2017 Feb 1. https://www.ncbi.nlm.nih.gov/pubmed/28052319

 

Poor sleep quality is associated with greater circulating pro-inflammatory cytokines and severity and frequency of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) symptoms in women

Abstract:

OBJECTIVE: Poor sleep quality has been linked to inflammatory processes and worse disease outcomes in the context of many chronic illnesses, but less is known in conditions such as chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). This study examines the relationships between sleep quality, pro-inflammatory cytokines, and CFS/ME symptoms.

METHODS: Sixty women diagnosed with CFS/ME were assessed using the Pittsburgh Sleep Quality Index (PSQI), Fatigue Symptom Inventory (FSI) and Center for Disease Control and Prevention (CDC)-based CFS/ME symptom questionnaires. Circulating plasma pro-inflammatory cytokine levels were measured by ELISA. Multiple regression analyses examined associations between sleep, cytokines and symptoms, controlling for age, education, and body mass index.

RESULTS: Poor sleep quality (PSQI global score) was associated with greater pro-inflammatory cytokine levels: interleukin-1β (IL-1β) (β=0.258, p=0.043), IL-6 (β=0.281, p=0.033), and tumor necrosis factor-alpha (TNF-α) (β=0.263, p=0.044). Worse sleep quality related to greater fatigue severity (β=0.395, p=0.003) and fatigue-related interference with daily activities (β=0.464, p<0.001), and more severe and frequent CDC-defined core CFS/ME symptoms (β=0.499, p<0.001, and β=0.556, p<0.001, respectively).

CONCLUSIONS: Results underscore the importance of managing sleep-related difficulties in this patient population. Further research is needed to identify the etiology of sleep disruptions in CFS/ME and mechanistic factors linking sleep quality to symptom severity and inflammatory processes.

Copyright © 2016 Elsevier B.V. All rights reserved.

 

Source: Milrad SF, Hall DL, Jutagir DR, Lattie EG, Ironson GH, Wohlgemuth W, Nunez MV, Garcia L, Czaja SJ, Perdomo DM, Fletcher MA, Klimas N, Antoni MH. Poor sleep quality is associated with greater circulating pro-inflammatory cytokines and severity and frequency of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) symptoms in women. J Neuroimmunol. 2017 Feb 15;303:43-50. doi: 10.1016/j.jneuroim.2016.12.008. Epub 2016 Dec 14. https://www.ncbi.nlm.nih.gov/pubmed/28038892

 

CDC Grand Rounds: Chronic Fatigue Syndrome – Advancing Research and Clinical Education

Abstract:

Chronic fatigue syndrome (CFS) is a complex and serious illness that is often misunderstood. Experts have noted that the terminology “chronic fatigue syndrome” can trivialize this illness and stigmatize persons who experience its symptoms (1). The name was coined by a group of clinicians convened by CDC in the late 1980s to develop a research case definition for the illness, which, at the time, was called chronic Epstein-Barr virus syndrome. The name CFS was suggested because of the characteristic persistent fatigue experienced by all those affected and the evidence that acute or reactivated Epstein-Barr virus infection was not associated with many cases (2).

However, the fatigue in this illness is striking and quite distinct from the common fatigue everyone experiences. A variety of other names have been used, including myalgic encephalomyelitis (ME), ME/CFS, chronic fatigue immune dysfunction, and most recently, systemic exertion intolerance disease (3). The lack of agreement about nomenclature need not be an impediment for advancing critically needed research and education. The term ME/CFS will be used in this article.

 

Source: Unger ER, Lin JS, Brimmer DJ, Lapp CW, Komaroff AL, Nath A, Laird S, Iskander J. CDC Grand Rounds: Chronic Fatigue Syndrome – Advancing Research and Clinical Education. MMWR Morb Mortal Wkly Rep. 2016 Dec 30;65(5051):1434-1438. doi: 10.15585/mmwr.mm655051a4. https://www.cdc.gov/mmwr/volumes/65/wr/mm655051a4.htm (Full article)

 

Metabolic profiling indicates impaired pyruvate dehydrogenase function in myalgic encephalopathy/chronic fatigue syndrome

Abstract:

Myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) is a debilitating disease of unknown etiology, with hallmark symptoms including postexertional malaise and poor recovery. Metabolic dysfunction is a plausible contributing factor.

We hypothesized that changes in serum amino acids may disclose specific defects in energy metabolism in ME/CFS. Analysis in 200 ME/CFS patients and 102 healthy individuals showed a specific reduction of amino acids that fuel oxidative metabolism via the TCA cycle, mainly in female ME/CFS patients. Serum 3-methylhistidine, a marker of endogenous protein catabolism, was significantly increased in male patients.

The amino acid pattern suggested functional impairment of pyruvate dehydrogenase (PDH), supported by increased mRNA expression of the inhibitory PDH kinases 1, 2, and 4; sirtuin 4; and PPARδ in peripheral blood mononuclear cells from both sexes. Myoblasts grown in presence of serum from patients with severe ME/CFS showed metabolic adaptations, including increased mitochondrial respiration and excessive lactate secretion. The amino acid changes could not be explained by symptom severity, disease duration, age, BMI, or physical activity level among patients.

These findings are in agreement with the clinical disease presentation of ME/CFS, with inadequate ATP generation by oxidative phosphorylation and excessive lactate generation upon exertion.

 

Source: Fluge Ø, Mella O, Bruland O, Risa K, Dyrstad SE, Alme K, Rekeland IG, Sapkota D, Røsland GV, Fosså A, Ktoridou-Valen I, Lunde S, Sørland K, Lien K, Herder I, Thürmer H, Gotaas ME, Baranowska KA, Bohnen LM, Schäfer C, McCann A, Sommerfelt K, Helgeland L, Ueland PM, Dahl O, Tronstad KJ. Metabolic profiling indicates impaired pyruvate dehydrogenase function in myalgic encephalopathy/chronic fatigue syndrome. JCI Insight. 2016 Dec 22;1(21):e89376. doi: 10.1172/jci.insight.89376. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5161229/ (Full article)