A Paradigm for Post-Covid-19 Fatigue Syndrome Analogous to ME/CFS

Abstract:

A significant proportion of COVID-19 patients are suffering from prolonged Post-COVID-19 Fatigue Syndrome, with characteristics typically found in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). However, no clear pathophysiological explanation, as yet, has been provided. A novel paradigm for a Post-COVID-19 Fatigue Syndrome is developed here from a recent unifying model for ME/CFS. Central to its rationale, SARS-CoV-2, in common with the triggers (viral and non-viral) of ME/CFS, is proposed to be a physiologically severe stressor, which could be targeting a stress-integrator, within the brain: the hypothalamic paraventricular nucleus (PVN). It is proposed that inflammatory mediators, released at the site of COVID-19 infection, would be transmitted as stress-signals, via humoral and neural pathways, which overwhelm this stress-center.

In genetically susceptible people, an intrinsic stress-threshold is suggested to be exceeded causing ongoing dysfunction to the hypothalamic PVN’s complex neurological circuitry. In this compromised state, the hypothalamic PVN might then be hyper-sensitive to a wide range of life’s ongoing physiological stressors. This could result in the reported post-exertional malaise episodes and more severe relapses, in common with ME/CFS, that perpetuate an ongoing disease state.

When a certain stress-tolerance-level is exceeded, the hypothalamic PVN can become an epicenter for microglia-induced activation and neuroinflammation, affecting the hypothalamus and its proximal limbic system, which would account for the range of reported ME/CFS-like symptoms. A model for Post-COVID-19 Fatigue Syndrome is provided to stimulate discussion and critical evaluation. Brain-scanning studies, incorporating increasingly sophisticated imaging technology should enable chronic neuroinflammation to be detected, even at a low level, in the finite detail required, thus helping to test this model, while advancing our understanding of Post-COVID-19 Fatigue Syndrome pathophysiology.

Source: Mackay A. A Paradigm for Post-Covid-19 Fatigue Syndrome Analogous to ME/CFS. Front Neurol. 2021 Aug 2;12:701419. doi: 10.3389/fneur.2021.701419. PMID: 34408721; PMCID: PMC8365156. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8365156/ (Full text)

Neurotoxicant exposures and rates of Chronic Multisymptom Illness and Kansas Gulf War Illness criteria in Gulf War deployed women veterans

Abstract:

Aims: This study analyzed deployment-related exposures and risk of Persian Gulf War Illness (GWI) in women veterans from the Veterans Affairs (VA) Cooperative Studies Program 585 Gulf War Era Cohort and Biorepository (GWECB CSP#585).

Main methods: We examined the associations between GW deployment-related exposures and case definitions for GWI in deployed GW women. Multivariate regression analyses controlling for demographic outcomes were performed.

Key findings: Surveys were obtained from 202 GW deployed women veterans. Self-reported exposure to smoke from oil well fires as well as chemical and biological warfare were the only exposures significantly associated with the Center for Disease Control and Prevention (CDC) GWI criteria. Seventy-nine women were excluded from the rest of the analyses as they met Kansas GW illness exclusion criteria. Eligible women who self-reported deployment-related exposure to smoke from oil wells, pyridostigmine bromide (PB) pills, pesticide cream, pesticide treated uniforms, and insect baits were significantly more likely to meet the Kansas GWI criteria (n = 123) than those unexposed and exposures were related to Kansas symptom subdomain endorsements.

Significance: These results suggest that women GW veterans reporting deployment related exposures of pesticide, oil well fire and PB pills are significantly more likely to meet the Kansas GWI criteria in this national cohort of GW women suggesting its utility in future studies. In addition, based on these results it appears that women exposed to particular toxicants during the war may benefit from more targeted treatment strategies dependent upon the mechanism of exposure of their toxicant induced outcomes.

Source: Krengel M, Sullivan K, Heboyan V, Zundel CG, Wilson CC, Klimas N, Coughlin SS. Neurotoxicant exposures and rates of Chronic Multisymptom Illness and Kansas Gulf War Illness criteria in Gulf War deployed women veterans. Life Sci. 2021 Sep 1;280:119623. doi: 10.1016/j.lfs.2021.119623. Epub 2021 May 15. PMID: 34004246. https://pubmed.ncbi.nlm.nih.gov/34004246/

Fine mapping of the major histocompatibility complex (MHC) in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) suggests involvement of both HLA class I and class II loci

Abstract:

The etiology of myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is unknown, but involvement of the immune system is one of the proposed underlying mechanisms. Human leukocyte antigen (HLA) associations are hallmarks of immune-mediated and autoimmune diseases. We have previously performed high resolution HLA genotyping and detected associations between ME/CFS and certain HLA class I and class II alleles. However, the HLA complex harbors numerous genes of immunological importance, and there is extensive and complex linkage disequilibrium across the region. In the current study, we aimed to fine map the association signals in the HLA complex by genotyping five additional classical HLA loci and 5,342 SNPs in 427 Norwegian ME/CFS patients, diagnosed according to the Canadian Consensus Criteria, and 480 healthy Norwegian controls.

SNP association analysis revealed two distinct and independent association signals (p≤0.001) tagged by rs4711249 in the HLA class I region and rs9275582 in the HLA class II region. Furthermore, the primary association signal in the HLA class II region was located within the HLA-DQ gene region, most likely due to HLA-DQB1, particularly the amino acid position 57 (aspartic acid/alanine) in the peptide binding groove, or an intergenic SNP upstream of HLA-DQB1. In the HLA class I region, the putative causal locus might map outside the classical HLA genes as the association signal spans several genes (DDR1, GTF2H4, VARS2, SFTA2 and DPCR1) with expression levels influenced by the ME/CFS associated SNP genotype.

Taken together, our results implicate the involvement of the MHC, and in particular the HLA-DQB1 gene, in ME/CFS. These findings should be replicated in larger cohorts, particularly to verify the putative involvement of HLA-DQB1, a gene important for antigen-presentation to T cells and known to harbor alleles providing the largest risk for well-established autoimmune diseases.

Source: Hajdarevic R, Lande A, Rekeland I, Rydland A, Strand EB, Sosa DD, Creary LE, Mella O, Egeland T, Saugstad OD, Fluge Ø, Lie BA, Viken MK. Fine mapping of the major histocompatibility complex (MHC) in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) suggests involvement of both HLA class I and class II loci. Brain Behav Immun. 2021 Aug 14:S0889-1591(21)00509-2. doi: 10.1016/j.bbi.2021.08.219. Epub ahead of print. PMID: 34403736. https://pubmed.ncbi.nlm.nih.gov/34403736/

Inflammation-type dysbiosis of the oral microbiome associates with the duration of COVID-19 symptoms and long-COVID

Abstract:

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the pandemic Coronavirus Disease 2019 (COVID-19) and now many face the burden of prolonged symptoms-long-lasting COVID-19 symptoms or “long-COVID”. Long-COVID is thought to be linked to immune dysregulation due to harmful inflammation, with the exact causes being unknown. Given the role of the microbiome in mediating inflammation, we aimed to examine the relationship between the oral microbiome and the duration of long-COVID symptoms. Tongue swabs were collected from patients presenting with symptoms concerning for COVID-19. Confirmed infections were followed until resolution of all symptoms.

Bacterial composition was determined by metagenomic sequencing. We used random forest modeling to identify microbiota and clinical covariates that associated with long-COVID symptoms. Of the patients followed, 63% (17/27) developed ongoing symptomatic COVID-19 and 37% (10/27) went on to long-COVID. Patients with prolonged symptoms had significantly higher abundances of microbiota that induce inflammation, such as members of the genera Prevotella and Veillonella. Of note are species that produce lipopolysaccharides and the similarity of long-COVID patients’ oral microbiome to those of patients with chronic fatigue syndrome. All together, we our findings suggest an association with the oral microbiome and long-COVID revealing the possibility that dysfunction of the oral microbiome may contribute to this draining disease.

Source: Haran JP, Bradley E, Zeamer AL, Cincotta L, Salive MC, Dutta P, Mutaawe S, Anya O, Meza-Segura M, Moormann AM, Ward DV, McCormick BA, Bucci V. Inflammation-type dysbiosis of the oral microbiome associates with the duration of COVID-19 symptoms and long-COVID. JCI Insight. 2021 Aug 17:152346. doi: 10.1172/jci.insight.152346. Epub ahead of print. PMID: 34403368. https://pubmed.ncbi.nlm.nih.gov/34403368/

Redox imbalance links COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Although most patients recover from acute COVID-19, some experience postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC). One subgroup of PASC is a syndrome called “long COVID-19,” reminiscent of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS is a debilitating condition, often triggered by viral and bacterial infections, leading to years-long debilitating symptoms including profound fatigue, postexertional malaise, unrefreshing sleep, cognitive deficits, and orthostatic intolerance. Some are skeptical that either ME/CFS or long COVID-19 involves underlying biological abnormalities. However, in this review, we summarize the evidence that people with acute COVID-19 and with ME/CFS have biological abnormalities including redox imbalance, systemic inflammation and neuroinflammation, an impaired ability to generate adenosine triphosphate, and a general hypometabolic state.

These phenomena have not yet been well studied in people with long COVID-19, and each of them has been reported in other diseases as well, particularly neurological diseases. We also examine the bidirectional relationship between redox imbalance, inflammation, energy metabolic deficits, and a hypometabolic state. We speculate as to what may be causing these abnormalities. Thus, understanding the molecular underpinnings of both PASC and ME/CFS may lead to the development of novel therapeutics.

Source: Paul BD, Lemle MD, Komaroff AL, Snyder SH. Redox imbalance links COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome. Proc Natl Acad Sci U S A. 2021 Aug 24;118(34):e2024358118. doi: 10.1073/pnas.2024358118. PMID: 34400495. https://pubmed.ncbi.nlm.nih.gov/34400495/

UK health standards body delays new ME guidance in therapy row

The National Institute for Health and Care Excellence (Nice) has withdrawn long-awaited landmark guidance on ME hours before its planned publication amid a backlash from medical groups.

Charities and patient groups fighting for greater recognition of the poorly understood condition as a medical illness rather than a psychological problem had welcomed the planned guidance, which was due to stop advising doctors to administer a controversial therapy.

This disputed therapy, called graded exercise therapy (GET), involves incremental increases in physical activity to gradually build up tolerance. Patient groups have argued its use suggests those with ME have no underlying physical problem but are having symptoms due to inactivity.

Read the rest of this article HERE.

Are enteroviruses behind mysterious outbreaks of chronic fatigue syndrome?

Chronic fatigue syndrome is a long-term illness with a wide range of symptoms, no known treatment, and undetermined origins. However, with as many as 65m people across the world living with the illness, researchers continue to search for answers.

Now, Prof Maureen Hanson of Cornell University discusses how she and graduate student James O’Neal searched through the research archives to see whether a genus of RNA viruses called enteroviruses are the most likely culprits and whether the findings have implications in future ‘long Covid’ research.

Like SARS-CoV-2, which causes Covid-19, viruses, enteroviruses (EVs) are RNA viruses that can lead to cause serious illness and death. One type of EV causes poliomyelitis, which is now largely conquered through near-universal vaccination.

But no vaccine exists against many other types of EVs, which are free to circulate widely. Indeed, the Centers for Disease Control and Prevention estimates between 10m-15m enteroviral infections occur each year in the US.

EVs have long been suspected as causal agents in outbreaks of an illness that is now usually named ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome). Outbreaks have been documented since the turn of the previous century and may have occurred earlier.

Many are unaware that ME/CFS can occur in epidemic form. The pathogen(s) inciting most of these outbreaks remain unidentified. One reason for this lamentable situation is that earlier virus identification technology was not as powerful as today’s methods.

Consider how quickly the complete sequence of SARS-CoV-2 was obtained not long after a new illness arose. But another reason that ME/CFS triggers are not known is the existing technology was not deployed to identify the agents causing multiple outbreaks in the mid-1980s. The failure of federal agencies to nor investigate these outbreaks, often dismissed as hysteria or unimportant, is well documented in investigative journalist Hillary Johnson’s Osler’s Web.

Read the rest of this article HERE.

Source: Frontiers Science News, August 12, 2o21. https://blog.frontiersin.org/2021/08/12/chronic-fatigue-syndrome-viruses-maureen-hanson-cornell-university/

Dysregulation of cellular energetics in Gulf War Illness

Abstract:

Gulf War Illness (GWI) is estimated to have affected about one third of the Veterans who participated in the first Persian Gulf War. The symptoms of GWI include chronic neurologic impairments, chronic fatigue syndrome, as well as fibromyalgia and immune system disorders, collectively referred to as chronic multi-symptom illness. Thirty years after the war, we still do not have an effective treatment for GWI. It is necessary to understand the molecular basis of the symptoms of GWI in order to develop appropriate therapeutic strategies. Cellular energetics are critical to the maintenance of cellular homeostasis, a process that is highly dependent on intact mitochondrial function and there is significant evidence from both human studies and animal models that mitochondrial impairments may lead to GWI symptoms.

The available clinical and pre-clinical data suggest that agents that improve mitochondrial function have the potential to restore cellular energetics and treat GWI. To date, the experiments conducted in animal models of GWI have mainly focused on neurobehavioral aspects of the illness. Additional studies to address the fundamental biological processes that trigger the dysregulation of cellular energetics in GWI are warranted to better understand the underlying pathology and to develop new treatment methods. This review highlights studies related to mitochondrial dysfunction observed in both GW veterans and in animal models of GWI.

Source: Raju RP, Terry AV. Dysregulation of cellular energetics in Gulf War Illness. Toxicology. 2021 Aug 10:152894. doi: 10.1016/j.tox.2021.152894. Epub ahead of print. PMID: 34389359. https://pubmed.ncbi.nlm.nih.gov/34389359/

The effect of stress on the transcriptomes of circulating immune cells in patients with Gulf War Illness

Abstract:

Aims: In an effort to gain further insight into the underlying mechanisms tied to disease onset and progression of Gulf War Illness (GWI), our team evaluated GWI patient response to stress utilizing RNA-Seq.

Main methods: The protocol included blood collection before exercise challenge (baseline), at maximal exertion, and after exercise challenge (recovery – four hours post-exercise challenge). Peripheral blood mononuclear cell (PBMC) transcriptomics data were analyzed to understand why GWI patients process stressors differently from their healthy counterparts.

Key findings: Our findings validate previously identified dysregulation of immune and inflammatory pathways among GWI patients as well as highlight novel immune and inflammatory markers of disease activity. These results provide a foundation for future research efforts in understanding GWI pathophysiology and creating targeted treatments.

Significance: Gulf War Illness is a complex, chronic, and debilitating multi-system illness impacting 25%-30% of the U.S. troops deployed to the 1990-1991 Gulf War. The condition is characterized by medically unexplained fatigue and affects multiple organ systems. Because the underlying mechanisms are largely unknown, patients receive symptom-based treatment, rather than targeting fundamental biological processes. To the best of our knowledge, this is the first study that applies RNA-Seq to analyze the effect of GWI, and the response to stressors in GWI, on the transcriptomic changes in circulating immune cells.

Source: Van Booven D, Zarnowski O, Perez M, Sarria L, Collado F, Hansotia K, Riegle S, Finger T, Fletcher MA, Klimas NG, Nathanson L. The effect of stress on the transcriptomes of circulating immune cells in patients with Gulf War Illness. Life Sci. 2021 Sep 15;281:119719. doi: 10.1016/j.lfs.2021.119719. Epub 2021 Jun 16. PMID: 34144055. https://pubmed.ncbi.nlm.nih.gov/34144055/

Exploring Symptom Fluctuations and Triggers in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Using Novel Patient-Centred N-of-1 Observational Designs: A Protocol for a Feasibility and Acceptability Study

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic condition of unknown aetiology associated with a range of disabling symptoms, including post-exertional malaise, chronic fatigue, musculoskeletal pain, orthostatic intolerance, unrefreshing sleep, and cognitive dysfunction. ME/CFS is a heterogeneous disorder, with significant variation in symptom type and severity between individuals, as well as within individuals over time. The diversity of ME/CFS symptom presentation makes management challenging; treatments supported by data from randomised controlled trials may not work for all individuals due to the variability in experienced symptoms. Studies using quantitative N-of-1 observational designs involve repeated outcome measurements in an individual over time and can generate rigorous individual-specific conclusions about symptom patterns and triggers in individuals with ME/CFS. This study aims to explore the feasibility and acceptability of using novel patient-centred N-of-1 observational designs to explore symptom fluctuations and triggers in ME/CFS at the individual level.

Methods and analysis: Individuals with a medical diagnosis of ME/CFS will be recruited through ME/CFS patient organisations to participate in a series of patient-centred N-of-1 observational studies. Using a wrist-worn electronic diary, participants will complete ecological momentary assessments of fatigue, stress, mood, and cognitive demand, three times per day for a period of 6-12 weeks. Personally relevant symptoms and triggers will also be incorporated into the questionnaire design. Physical activity will be objectively measured via an integrated accelerometer. Feasibility and acceptability outcomes will be assessed including the percentage of diary entries completed, as well as recruitment and retention rate, feasibility of analysing and interpreting the data collected, and participant views about participation elicited via a post-study semi-structured interview.

Discussion: This study will assess the feasibility and acceptability of patient-centred N-of-1 observational studies to assess diseases with complex presentations such as ME/CFS, as well as provide individual-level evidence about fluctuations and triggers of ME/CFS symptoms that may aid self-management.

Trial registration: Australian and New Zealand Clinical Trials Registry: ACTRN12618001898246. Registered on 22 November 2018.

Source: McDonald S, Tan SX, Banu S, van Driel M, McGree JM, Mitchell G, Nikles J. Exploring Symptom Fluctuations and Triggers in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Using Novel Patient-Centred N-of-1 Observational Designs: A Protocol for a Feasibility and Acceptability Study. Patient. 2021 Aug 9. doi: 10.1007/s40271-021-00540-0. Epub ahead of print. PMID: 34368926.  https://pubmed.ncbi.nlm.nih.gov/34368926/