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Chaves-Filho AM, Braniff O, Angelova A, Deng Y, Tremblay MÈ. Chronic inflammation, neuroglial dysfunction, and plasmalogen deficiency as a new pathobiological hypothesis addressing the overlap between post-COVID-19 symptoms and myalgic encephalomyelitis/chronic fatigue syndrome. Brain Res Bull 2023; 201:110702. [PMID: 37423295 DOI: 10.1016/j.brainresbull.2023.110702] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/13/2023] [Accepted: 07/06/2023] [Indexed: 07/11/2023]
Abstract
After five waves of coronavirus disease 2019 (COVID-19) outbreaks, it has been recognized that a significant portion of the affected individuals developed long-term debilitating symptoms marked by chronic fatigue, cognitive difficulties ("brain fog"), post-exertional malaise, and autonomic dysfunction. The onset, progression, and clinical presentation of this condition, generically named post-COVID-19 syndrome, overlap significantly with another enigmatic condition, referred to as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Several pathobiological mechanisms have been proposed for ME/CFS, including redox imbalance, systemic and central nervous system inflammation, and mitochondrial dysfunction. Chronic inflammation and glial pathological reactivity are common hallmarks of several neurodegenerative and neuropsychiatric disorders and have been consistently associated with reduced central and peripheral levels of plasmalogens, one of the major phospholipid components of cell membranes with several homeostatic functions. Of great interest, recent evidence revealed a significant reduction of plasmalogen contents, biosynthesis, and metabolism in ME/CFS and acute COVID-19, with a strong association to symptom severity and other relevant clinical outcomes. These bioactive lipids have increasingly attracted attention due to their reduced levels representing a common pathophysiological manifestation between several disorders associated with aging and chronic inflammation. However, alterations in plasmalogen levels or their lipidic metabolism have not yet been examined in individuals suffering from post-COVID-19 symptoms. Here, we proposed a pathobiological model for post-COVID-19 and ME/CFS based on their common inflammation and dysfunctional glial reactivity, and highlighted the emerging implications of plasmalogen deficiency in the underlying mechanisms. Along with the promising outcomes of plasmalogen replacement therapy (PRT) for various neurodegenerative/neuropsychiatric disorders, we sought to propose PRT as a simple, effective, and safe strategy for the potential relief of the debilitating symptoms associated with ME/CFS and post-COVID-19 syndrome.
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Affiliation(s)
| | - Olivia Braniff
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Angelina Angelova
- Université Paris-Saclay, CNRS, Institut Galien Paris-Saclay, F-91400 Orsay, France
| | - Yuru Deng
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, China.
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada; Department of Molecular Medicine, Université Laval, Québec City, Québec, Canada; Neurology and Neurosurgery Department, McGill University, Montréal, Québec, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada; Centre for Advanced Materials and Related Technology (CAMTEC) and Institute on Aging and Lifelong Health (IALH), University of Victoria, Victoria, British Columbia, Canada.
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Brown A, Jason LA. Meta-analysis investigating post-exertional malaise between patients and controls. J Health Psychol 2020; 25:2053-2071. [PMID: 29974812 PMCID: PMC7440642 DOI: 10.1177/1359105318784161] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Post-exertional malaise is either required or included in many previously proposed case definitions of myalgic encephalomyelitis/chronic fatigue syndrome. A meta-analysis of odds ratios (ORs; association between patient status and post-exertional malaise status) and a number of potential moderators (i.e. study-level characteristics) of effect size were conducted. Post-exertional malaise was found to be 10.4 times more likely to be associated with a myalgic encephalomyelitis/chronic fatigue syndrome diagnosis than with control status. Significant moderators of effect size included patient recruitment strategy and control selection. These findings suggest that post-exertional malaise should be considered a cardinal symptom of myalgic encephalomyelitis/chronic fatigue syndrome.
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Vink M, Vink-Niese F. Work Rehabilitation and Medical Retirement for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. A Review and Appraisal of Diagnostic Strategies. Diagnostics (Basel) 2019; 9:diagnostics9040124. [PMID: 31547009 PMCID: PMC6963831 DOI: 10.3390/diagnostics9040124] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 01/31/2023] Open
Abstract
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome leads to severe functional impairment and work disability in a considerable number of patients. The majority of patients who manage to continue or return to work, work part-time instead of full time in a physically less demanding job. The prognosis in terms of returning to work is poor if patients have been on long-term sick leave for more than two to three years. Being older and more ill when falling ill are associated with a worse employment outcome. Cognitive behavioural therapy and graded exercise therapy do not restore the ability to work. Consequently, many patients will eventually be medically retired depending on the requirements of the retirement policy, the progress that has been made since they have fallen ill in combination with the severity of their impairments compared to the sort of work they do or are offered to do. However, there is one thing that occupational health physicians and other doctors can do to try and prevent chronic and severe incapacity in the absence of effective treatments. Patients who are given a period of enforced rest from the onset, have the best prognosis. Moreover, those who work or go back to work should not be forced to do more than they can to try and prevent relapses, long-term sick leave and medical retirement.
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Affiliation(s)
- Mark Vink
- Family and Insurance Physician, 1096 HZ Amsterdam, The Netherlands.
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Panelli S, Lorusso L, Balestrieri A, Lupo G, Capelli E. XMRV and Public Health: The Retroviral Genome Is Not a Suitable Template for Diagnostic PCR, and Its Association with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Appears Unreliable. Front Public Health 2017; 5:108. [PMID: 28589117 PMCID: PMC5439170 DOI: 10.3389/fpubh.2017.00108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 05/02/2017] [Indexed: 11/13/2022] Open
Abstract
A few years ago, a highly significant association between the xenotropic murine leukemia virus-related virus (XMRV) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a complex debilitating disease of poorly understood etiology and no definite treatment, was reported in Science, raising concern for public welfare. Successively, the failure to reproduce these findings, and the suspect that the diagnostic PCR was vitiated by laboratory contaminations, led to the retraction of the paper. Notwithstanding, XMRV continued to be the subject of researches and public debates. Occasional positivity in humans was also detected recently, even if the data always appeared elusive and non-reproducible. In this study, we discuss the current status of this controversial association and propose that a major role in the unreliability of the results was played by the XMRV genomic composition in itself. In this regard, we present bioinformatic analyses that show: (i) aspecific, spurious annealings of the available primers in multiple homologous sites of the human genome; (ii) strict homologies between whole XMRV genome and interspersed repetitive elements widespread in mammalian genomes. To further detail this scenario, we screen several human and mammalian samples by using both published and newly designed primers. The experimental data confirm that available primers are far from being selective and specific. In conclusion, the occurrence of highly conserved, repeated DNA sequences in the XMRV genome deeply undermines the reliability of diagnostic PCRs by leading to artifactual and spurious amplifications. Together with all the other evidences, this makes the association between the XMRV retrovirus and CFS totally unreliable.
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Affiliation(s)
- Simona Panelli
- Department of Earth and Environmental Sciences, Section of Animal Biology, University of Pavia, Pavia, Italy.,Centre for Health Technologies (C.H.T.), University of Pavia, Pavia, Italy
| | - Lorenzo Lorusso
- Neurology Unit, A.S.S.T. Franciacorta, Chiari (Brescia), Italy
| | | | - Giuseppe Lupo
- Department of Earth and Environmental Sciences, Section of Animal Biology, University of Pavia, Pavia, Italy.,Centre for Health Technologies (C.H.T.), University of Pavia, Pavia, Italy
| | - Enrica Capelli
- Department of Earth and Environmental Sciences, Section of Animal Biology, University of Pavia, Pavia, Italy.,Centre for Health Technologies (C.H.T.), University of Pavia, Pavia, Italy
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Twisk FNM. Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms. World J Methodol 2015; 5:68-87. [PMID: 26140274 PMCID: PMC4482824 DOI: 10.5662/wjm.v5.i2.68] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/10/2015] [Accepted: 05/27/2015] [Indexed: 02/06/2023] Open
Abstract
Although myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) are considered to be synonymous, the definitional criteria for ME and CFS define two distinct, partially overlapping, clinical entities. ME, whether defined by the original criteria or by the recently proposed criteria, is not equivalent to CFS, let alone a severe variant of incapacitating chronic fatigue. Distinctive features of ME are: muscle weakness and easy muscle fatigability, cognitive impairment, circulatory deficits, a marked variability of the symptoms in presence and severity, but above all, post-exertional “malaise”: a (delayed) prolonged aggravation of symptoms after a minor exertion. In contrast, CFS is primarily defined by (unexplained) chronic fatigue, which should be accompanied by four out of a list of 8 symptoms, e.g., headaches. Due to the subjective nature of several symptoms of ME and CFS, researchers and clinicians have questioned the physiological origin of these symptoms and qualified ME and CFS as functional somatic syndromes. However, various characteristic symptoms, e.g., post-exertional “malaise” and muscle weakness, can be assessed objectively using well-accepted methods, e.g., cardiopulmonary exercise tests and cognitive tests. The objective measures acquired by these methods should be used to accurately diagnose patients, to evaluate the severity and impact of the illness objectively and to assess the positive and negative effects of proposed therapies impartially.
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Adamowicz JL, Caikauskaite I, Friedberg F. Defining recovery in chronic fatigue syndrome: a critical review. Qual Life Res 2014; 23:2407-16. [PMID: 24791749 DOI: 10.1007/s11136-014-0705-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2014] [Indexed: 11/27/2022]
Abstract
PURPOSE In chronic fatigue syndrome (CFS), the lack of consensus on how recovery should be defined or interpreted has generated controversy and confusion. The purpose of this paper was to systematically review, compare, and evaluate the definitions of recovery reported in the CFS literature and to make recommendations about the scope of recovery assessments. METHODS A search was done using the MEDLINE, PubMed, PsycINFO, CINAHL, and Cochrane databases for peer review papers that contained the search terms "chronic fatigue syndrome" and "recovery," "reversal," "remission," and/or "treatment response." RESULTS From the 22 extracted studies, recovery was operationally defined by reference with one or more of these domains: (1) pre-morbid functioning; (2) both fatigue and function; (3) fatigue (or related symptoms) alone; (4) function alone; and/or (5) brief global assessment. Almost all of the studies measuring recovery in CFS did so differently. The brief global assessment was the most common outcome measure used to define recovery. Estimates of recovery ranged from 0 to 66 % in intervention studies and 2.6 to 62 % in naturalistic studies. CONCLUSIONS Given that the term "recovery" was often based on limited assessments and less than full restoration of health, other more precise and accurate labels (e.g., clinically significant improvement) may be more appropriate and informative. In keeping with common understandings of the term recovery, we recommend a consistent definition that captures a broad-based return to health with assessments of both fatigue and function as well as the patient's perceptions of his/her recovery status.
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Affiliation(s)
- Jenna L Adamowicz
- Department of Psychiatry and Behavioral Sciences, Stony Brook University, Putnam Hall/South Campus, Stony Brook, NY, 11794-8790, USA,
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Morris G, Maes M. A neuro-immune model of Myalgic Encephalomyelitis/Chronic fatigue syndrome. Metab Brain Dis 2013; 28:523-40. [PMID: 22718491 DOI: 10.1007/s11011-012-9324-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 06/07/2012] [Indexed: 12/15/2022]
Abstract
This paper proposes a neuro-immune model for Myalgic Encephalomyelitis/Chronic fatigue syndrome (ME/CFS). A wide range of immunological and neurological abnormalities have been reported in people suffering from ME/CFS. They include abnormalities in proinflammatory cytokines, raised production of nuclear factor-κB, mitochondrial dysfunctions, autoimmune responses, autonomic disturbances and brain pathology. Raised levels of oxidative and nitrosative stress (O&NS), together with reduced levels of antioxidants are indicative of an immuno-inflammatory pathology. A number of different pathogens have been reported either as triggering or maintaining factors. Our model proposes that initial infection and immune activation caused by a number of possible pathogens leads to a state of chronic peripheral immune activation driven by activated O&NS pathways that lead to progressive damage of self epitopes even when the initial infection has been cleared. Subsequent activation of autoreactive T cells conspiring with O&NS pathways cause further damage and provoke chronic activation of immuno-inflammatory pathways. The subsequent upregulation of proinflammatory compounds may activate microglia via the vagus nerve. Elevated proinflammatory cytokines together with raised O&NS conspire to produce mitochondrial damage. The subsequent ATP deficit together with inflammation and O&NS are responsible for the landmark symptoms of ME/CFS, including post-exertional malaise. Raised levels of O&NS subsequently cause progressive elevation of autoimmune activity facilitated by molecular mimicry, bystander activation or epitope spreading. These processes provoke central nervous system (CNS) activation in an attempt to restore immune homeostatsis. This model proposes that the antagonistic activities of the CNS response to peripheral inflammation, O&NS and chronic immune activation are responsible for the remitting-relapsing nature of ME/CFS. Leads for future research are suggested based on this neuro-immune model.
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Morris G, Anderson G, Galecki P, Berk M, Maes M. A narrative review on the similarities and dissimilarities between myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and sickness behavior. BMC Med 2013; 11:64. [PMID: 23497361 PMCID: PMC3751187 DOI: 10.1186/1741-7015-11-64] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 03/08/2013] [Indexed: 12/14/2022] Open
Abstract
It is of importance whether myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a variant of sickness behavior. The latter is induced by acute infections/injury being principally mediated through proinflammatory cytokines. Sickness is a beneficial behavioral response that serves to enhance recovery, conserves energy and plays a role in the resolution of inflammation. There are behavioral/symptomatic similarities (for example, fatigue, malaise, hyperalgesia) and dissimilarities (gastrointestinal symptoms, anorexia and weight loss) between sickness and ME/CFS. While sickness is an adaptive response induced by proinflammatory cytokines, ME/CFS is a chronic, disabling disorder, where the pathophysiology is related to activation of immunoinflammatory and oxidative pathways and autoimmune responses. While sickness behavior is a state of energy conservation, which plays a role in combating pathogens, ME/CFS is a chronic disease underpinned by a state of energy depletion. While sickness is an acute response to infection/injury, the trigger factors in ME/CFS are less well defined and encompass acute and chronic infections, as well as inflammatory or autoimmune diseases. It is concluded that sickness behavior and ME/CFS are two different conditions.
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Affiliation(s)
- Gerwyn Morris
- Tir Na Nog, Bryn Road Seaside 87, Llanelli, SA152LW, UK
| | - George Anderson
- CRC Clinical Research Centre/Communications, Laurel Street 57, Glasgow, G11 7QT,UK
| | - Piotr Galecki
- Department of Adult Psychiatry, Medical University of Lodz, Aleksandrowska 159, Lodz, 91229, Poland
| | - Michael Berk
- Barwon Health, School of Medicine, Deakin University, PO Box 291, Geelong, 3220, Australia
- Orygen Youth Health Research Centre, Poplar Road 35, Parkville, 3052, Australia
- Centre of Youth Mental Health, University of Melbourne, Poplar Road 35, Parkville, 3052, Australia
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Kenneth Myer Building, Royal Parade 30, Parkville, 3052, Australia
- Department of Psychiatry, University of Melbourne, Level 1 North, Main Block, Royal Melbourne Hospital, Parkville, 3052, Australia
| | - Michael Maes
- Barwon Health, School of Medicine, Deakin University, PO Box 291, Geelong, 3220, Australia
- Department of Psychiatry, Chulalongkorn University, Rama 4 Road 1873, Pathumwan, Bangkok, 10330, Thailand
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Maes M, Twisk FNM, Johnson C. Myalgic Encephalomyelitis (ME), Chronic Fatigue Syndrome (CFS), and Chronic Fatigue (CF) are distinguished accurately: results of supervised learning techniques applied on clinical and inflammatory data. Psychiatry Res 2012; 200:754-60. [PMID: 22521895 DOI: 10.1016/j.psychres.2012.03.031] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 03/17/2012] [Indexed: 10/28/2022]
Abstract
There is much debate on the diagnostic classification of Myalgic Encephalomyelitis (ME), Chronic Fatigue Syndrome (CFS) and chronic fatigue (CF). Post-exertional malaise (PEM) is stressed as a key feature. This study examines whether CF and CFS, with and without PEM, are distinct diagnostic categories. Fukuda's criteria were used to diagnose 144 patients with chronic fatigue and identify patients with CFS and CF, i.e. those not fulfilling the Fukuda's criteria. PEM was rated by means of a scale with defined scale steps between 0 and 6. CFS patients were divided into those with PEM lasting more than 24h (labeled: ME) and without PEM (labeled: CFS). The 12-item Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale was used to measure severity of illness. Plasma interleukin-1 (IL-1), tumor necrosis factor (TNF)α, and lysozyme, and serum neopterin were employed as external validating criteria. Using fatigue, a subjective feeling of infection and PEM we found that ME, CFS, and CF were distinct categories. Patients with ME had significantly higher scores on concentration difficulties and a subjective experience of infection, and higher levels of IL-1, TNFα, and neopterin than patients with CFS. These biomarkers were significantly higher in ME and CFS than in CF patients. PEM loaded highly on the first two factors subtracted from the data set, i.e. "malaise-sickness" and "malaise-hyperalgesia". Fukuda's criteria are adequate to make a distinction between ME/CFS and CF, but ME/CFS patients should be subdivided into ME (with PEM) and CFS (without PEM).
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Affiliation(s)
- Michael Maes
- Maes Clinics @ TRIA, Piyavate Hospital, 998 Rimklongsamsen Road, Bangkok 10310, Thailand.
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Andersen MM, Permin H, Albrecht F. Illness and disability in Danish Chronic Fatigue Syndrome patients at diagnosis and 5-year follow-up. J Psychosom Res 2004; 56:217-29. [PMID: 15016582 DOI: 10.1016/s0022-3999(03)00065-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2001] [Accepted: 03/03/2003] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Evaluation of the life impact of Chronic Fatigue Syndrome (CFS) over 5 years. METHODS Thirty-three adult patients meeting 1988 and 1994 CDC case criteria answered identical questionnaires at diagnosis and 5 years later, when a retrospective questionnaire was also completed. RESULTS Work disability was very high and increased further, social isolation remained high, emotional adjustment improved. There were increased problems with reading and with allergies. Two measures of improvement were used: The relation between these measures was weak. Length of illness, extent of disability and emotional adjustment were poorly related to measures of improvement. Average illness scores were unchanged, but most individuals improved in some ways while worsening or remaining the same in others. Only one participant (3%) neared recovery, one other was substantially better but still severely disabled. CONCLUSION CFS patients exhibit severe, long-term functional impairment. Substantial improvement is uncommon, less than 6%. Allergies and aspects of cognition may worsen, emotional adjustment often improves.
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Affiliation(s)
- M M Andersen
- Department of Infectious Diseases M5132, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
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