Tag: pathomechanism

Low Vasopressin in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (P4-4.006)

Abstract:

Objective: To shed light on the pathophysiology of water homeostasis in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), classified by WHO as a neurological disease (ICD 10 code G933).

Background: The complex symptomatology of ME/CFS includes signs suggesting abnormal water homeostasis and hypovolemia. Since many patients report polyuria-polydipsia, we conducted an observational series of plasma and urine osmolality as well as plasma levels of vasopressin (VP) in consecutive patients diagnosed with ME/CFS according to the Canadian Consensus Criteria.

Design/Methods: Plasma and urine osmolality (P-Osm and U-Osm, respectively) and plasma VP levels were measured in 111 patients after overnight fasting and 10-hour fluid deprivation. The clinical routine also included brain MRI and blood chemistry.

Results: Following the fluid deprivation P-Osm was above normal (>292 mOsm/kg) in 61 patients (55.0%) and U-Osm below normal (< 750 mOsm/kg) in 74 patients (66.7%). VP-levels were below the level of detection (<1.6 pg/mL) in 91 patients (82.0%). A normal level of VP in relation to their P-Osm was found in 11 patients (9.9 %). The state resembling a central type of diabetes insipidus (cDI) would in the absence of hypophyseal imaging findings and blood chemistry consistent with any other hypophyseal hormonal defect be classified as idiopathic.

Conclusions: Our findings suggest that deficiency of vasopressin secretion is a fundamental measurable part of the disease mechanisms, which may underlie a number of symptoms in ME/CFS, including the common complaint of orthostatic intolerance.

Source: Helena Huhmar, Lauri Soinne, Per Sjögren, Bo Christer Bertilson, Per Hamid Ghatan, Björn Bragée, and Olli Polo. Low Vasopressin in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (P4-4.006) Neurology, April 9, 2024 issue 102 (17_supplement_1) https://doi.org/10.1212/WNL.000000000020576 https://www.neurology.org/doi/10.1212/WNL.0000000000205761

Unravelling shared mechanisms: insights from recent ME/CFS research to illuminate long COVID pathologies

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic illness often triggered by an initiating acute event, mainly viral infections. The transition from acute to chronic disease remains unknown, but interest in this phenomenon has escalated since the COVID-19 pandemic and the post-COVID-19 illness, termed ‘long COVID’ (LC). Both ME/CFS and LC share many clinical similarities.

Here, we present recent findings in ME/CFS research focussing on proposed disease pathologies shared with LC. Understanding these disease pathologies and how they influence each other is key to developing effective therapeutics and diagnostic tests. Given that ME/CFS typically has a longer disease duration compared with LC, with symptoms and pathologies evolving over time, ME/CFS may provide insights into the future progression of LC.

Source: Annesley SJ, Missailidis D, Heng B, Josev EK, Armstrong CW. Unravelling shared mechanisms: insights from recent ME/CFS research to illuminate long COVID pathologies. Trends Mol Med. 2024 Mar 4:S1471-4914(24)00028-5. doi: 10.1016/j.molmed.2024.02.003. Epub ahead of print. PMID: 38443223. https://www.sciencedirect.com/science/article/pii/S1471491424000285 (Full text)

Subcortical and Default Mode Network connectivity is impaired in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex chronic condition with core symptoms of fatigue, and cognitive dysfunction suggesting a key role for the central nervous system, in the pathophysiology of this disease. Several studies have reported altered functional connectivity (FC) related to motor and cognitive deficits in ME/CFS patients. In this study, we compared functional connectivity differences between 31 ME/CFS and 15 healthy controls (HC) using 7 Tesla MRI. Functional scans were acquired during a cognitive Stroop color-word task and blood oxygen level-dependent (BOLD) time-series were computed for 27 regions of interest (ROIs) in the cerebellum, brainstem, and salience and default mode networks.

Region-based comparison detected reduced FC between the pontine nucleus and cerebellum vermis IX (p=0.027) for ME/CFS patients compared to HC. Our ROI-to-voxel analysis found significant impairment of FC within ponto-cerebellar regions in ME/CFS. Correlation analyses of connectivity with clinical scores in ME/CFS patients detected associations of FC with ‘duration of illness’ and ‘memory scores’ in salience network hubs and cerebellum vermis, and with ‘respiratory rate’ within medulla and the default mode network FC.

This novel investigation is the first to report extensive involvement of aberrant ponto-cerebellar connections consistent with ME/CFS symptomatology. This highlights the involvement of the brainstem and the cerebellum in the pathomechanism of ME/CFS.

Source: Maira INDERYAS, Kiran Thapaliya, Sonya Marshall-Gradisnik, Markus Barth, Leighton Barnden. Subcortical and Default Mode Network connectivity is impaired in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Front. Neurosci. Sec. Brain Imaging Methods. Volume 17 – 2023 | doi: 10.3389/fnins.2023.1318094 https://www.frontiersin.org/articles/10.3389/fnins.2023.1318094/full (Full text)

The potential role of ocular and otolaryngological mucus proteins in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating illness associated with a constellation of other symptoms. While the most common symptom is unrelenting fatigue, many individuals also report suffering from rhinitis, dry eyes and a sore throat.

Mucin proteins are responsible for contributing to the formation of mucosal membranes throughout the body. These mucosal pathways contribute to the body’s defense mechanisms involving pathogenic onset. When compromised by pathogens the epithelium releases numerous cytokines and enters a prolonged state of inflammation to eradicate any particular infection.

Based on genetic analysis, and computational theory and modeling we hypothesize that mucin protein dysfunction may contribute to ME/CFS symptoms due to the inability to form adequate mucosal layers throughout the body, especially in the ocular and otolaryngological pathways leading to low grade chronic inflammation and the exacerbation of symptoms.

Source: Huitsing K, Tritsch T, Arias FJC, Collado F, Aenlle KK, Nathason L, Fletcher MA, Klimas NG, Craddock TJA. The potential role of ocular and otolaryngological mucus proteins in myalgic encephalomyelitis/chronic fatigue syndrome. Mol Med. 2024 Jan 3;30(1):1. doi: 10.1186/s10020-023-00766-8. PMID: 38172662. https://molmed.biomedcentral.com/articles/10.1186/s10020-023-00766-8 (Full text)

Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective cohort study

Abstract:

Background: Accumulating evidence suggests that autonomic dysfunction and persistent systemic inflammation are common clinical features in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID. However, there is limited knowledge regarding their potential association with circulating biomarkers and illness severity status.

Methods: This prospective, cross-sectional, case-control cohort study aimed to distinguish between the two patient populations by using self-reported outcome measures and circulating biomarkers to assess endothelial function and systemic inflammation. Thirty-one individuals with ME/CFS, 23 individuals with long COVID, and 31 matched healthy subjects were included. Regression analysis was used to examine associations between self-reported outcome measures and circulating biomarkers in study participants. Classification across groups was based on principal component and discriminant analyses.

Results: Four ME/CFS patients (13%), 1 with long COVID (4%), and 1 healthy control (3%) presented postural orthostatic tachycardia syndrome (POTS) with the 10-min NASA lean test. Compared with healthy controls, ME/CFS and long COVID subjects showed higher levels of ET-1 (p < 0.05) and VCAM-1 (p < 0.001), and lower levels of nitrites (NOx assessed as NO2– + NO3–) (p < 0.01). ME/CFS patients also showed higher levels of serpin E1 (PAI-1) and E-selectin than did both long COVID and control subjects (p < 0.01 in all cases). Long COVID patients had lower TSP-1 levels than did ME/CFS patients and healthy controls (p < 0.001). As for inflammation biomarkers, both long COVID and ME/CFS subjects had higher levels of TNF-α than did healthy controls (p < 0.01 in both comparisons). Compared with controls, ME/CFS patients had higher levels of IL-1β (p < 0.001), IL-4 (p < 0.001), IL-6 (p < 0.01), IL-10 (p < 0.001), IP-10 (p < 0.05), and leptin (p < 0.001). Principal component analysis supported differentiation between groups based on self-reported outcome measures and endothelial and inflammatory biomarkers.

Conclusions: Our findings revealed that combining biomarkers of endothelial dysfunction and inflammation with outcome measures differentiate ME/CFS and Long COVID using robust discriminant analysis of principal components. Further research is needed to provide a more comprehensive characterization of these underlying pathomechanisms, which could be promising targets for therapeutic and preventive strategies in these conditions.

Source: Joan Carles Domingo, Federica Battistini, Begoña Cordobilla et al. Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective cohort study, 16 December 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3736031/v1] https://www.researchsquare.com/article/rs-3736031/v1 (Full text)

Urine Metabolite Analysis to Identify Pathomechanisms of Long COVID: A Pilot Study

Abstract:

Background: Around 10% of people who had COVID-9 infection suffer from persistent symptoms such as fatigue, dyspnoea, chest pain, arthralgia/myalgia, sleep disturbances, cognitive dysfunction and impairment of mental health. Different underlying pathomechanisms appear to be involved, in particular inflammation, alterations in amino acid metabolism, autonomic dysfunction and gut dysbiosis.

Aim: As routine tests are often inconspicuous in patients with Long COVID (LC), similarly to patients suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), accessible biomarkers indicating dysregulation of specific pathways are urgently needed to identify underlying pathomechanisms and enable personalized medicine treatment. Within this pilot study we aimed to proof traceability of altered metabolism by urine analysis.

Patients and methods: Urine metabolome analyses were performed to investigate the metabolic signature of patients with LC (n = 25; 20 women, 5 men) in comparison to healthy controls (Ctrl, n = 8; 7 women, 1 man) and individuals with ME/CFS (n = 8; 2 women, 6 men). Concentrations of neurotransmitter precursors tryptophan, phenylalanine and their downstream metabolites, as well as their association with symptoms (fatigue, anxiety and depression) in the patients were examined.

Results and conclusion: Phenylalanine levels were significantly lower in both the LC and ME/CFS patient groups when compared to the Ctrl group. In many LC patients, the concentrations of downstream metabolites of tryptophan and tyrosine, such as serotonin, dopamine and catecholamines, deviated from the reference ranges. Several symptoms (sleep disturbance, pain or autonomic dysfunction) were associated with certain metabolites. Patients experiencing fatigue had lower levels of kynurenine, phenylalanine and a reduced kynurenine to tryptophan ratio (Kyn/Trp). Lower concentrations of gamma-aminobutyric acid (GABA) and higher activity of kynurenine 3-monooxygenase (KMO) were observed in patients with anxiety.

Conclusively, our results suggest that amino acid metabolism and neurotransmitter synthesis is disturbed in patients with LC and ME/CFS. The identified metabolites and their associated dysregulations could serve as potential biomarkers for elucidating underlying pathomechanisms thus enabling personalized treatment strategies for these patient populations.

Source: Taenzer M, Löffler-Ragg J, Schroll A, Monfort-Lanzas P, Engl S, Weiss G, Brigo N, Kurz K. Urine Metabolite Analysis to Identify Pathomechanisms of Long COVID: A Pilot Study. Int J Tryptophan Res. 2023 Dec 22;16:11786469231220781. doi: 10.1177/11786469231220781. PMID: 38144169; PMCID: PMC10748708. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10748708/ (Full text)

Understanding, diagnosing, and treating Myalgic encephalomyelitis/chronic fatigue syndrome – State of the art: Report of the 2nd international meeting at the Charité fatigue center

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a devastating disease affecting millions of people worldwide. Due to the 2019 pandemic of coronavirus disease (COVID-19), we are facing a significant increase of ME/CFS prevalence. On May 11th to 12th, 2023, the second international ME/CFS conference of the Charité Fatigue Center was held in Berlin, Germany, focusing on pathomechanisms, diagnosis, and treatment.

During the two-day conference, more than 100 researchers from various research fields met on-site and over 700 attendees participated online to discuss the state of the art and novel findings in this field. Key topics from the conference included: the role of the immune system, dysfunction of endothelial and autonomic nervous system, and viral reactivation. Furthermore, there were presentations on innovative diagnostic measures and assessments for this complex disease, cutting-edge treatment approaches, and clinical studies.

Despite the increased public attention due to the COVID-19 pandemic, the subsequent rise of Long COVID-19 cases, and the rise of funding opportunities to unravel the pathomechanisms underlying ME/CFS, this severe disease remains highly underresearched. Future adequately funded research efforts are needed to further explore the disease etiology and to identify diagnostic markers and targeted therapies.

Source: Steiner S, Fehrer A, Hoheisel F, Schoening S, Aschenbrenner A, Babel N, Bellmann-Strobl J, Finke C, Fluge Ø, Froehlich L, Goebel A, Grande B, Haas JP, Hohberger B, Jason LA, Komaroff AL, Lacerda E, Liebl M, Maier A, Mella O, Nacul L, Paul F, Prusty BK, Puta C, Riemekasten G, Ries W, Rowe PC, Sawitzki B, Shoenfeld Y, Schultze JL, Seifert M, Sepúlveda N, Sotzny F, Stein E, Stingl M, Ufer F, Veauthier C, Westermeier F, Wirth K, Wolfarth B, Zalewski P, Behrends U, Scheibenbogen C. Understanding, diagnosing, and treating Myalgic encephalomyelitis/chronic fatigue syndrome – State of the art: Report of the 2nd international meeting at the Charité fatigue center. Autoimmun Rev. 2023 Sep 22:103452. doi: 10.1016/j.autrev.2023.103452. Epub ahead of print. PMID: 37742748. https://www.sciencedirect.com/science/article/abs/pii/S1568997223001866

Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID?

Abstract:

Both myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) and long COVID (LC) are characterized by similar immunological alterations, persistence of chronic viral infection, autoimmunity, chronic inflammatory state, viral reactivation, hypocortisolism, and microclot formation. They also present with similar symptoms such as asthenia, exercise intolerance, sleep disorders, cognitive dysfunction, and neurological and gastrointestinal complaints. In addition, both pathologies present Epstein-Barr virus (EBV) reactivation, indicating the possibility of this virus being the link between both pathologies.

Therefore, we propose that latency and recurrent EBV reactivation could generate an acquired immunodeficiency syndrome in three steps: first, an acquired EBV immunodeficiency develops in individuals with “weak” EBV HLA-II haplotypes, which prevents the control of latency I cells. Second, ectopic lymphoid structures with EBV latency form in different tissues (including the CNS), promoting inflammatory responses and further impairment of cell-mediated immunity.

Finally, immune exhaustion occurs due to chronic exposure to viral antigens, with consolidation of the disease. In the case of LC, prior to the first step, there is the possibility of previous SARS-CoV-2 infection in individuals with “weak” HLA-II haplotypes against this virus and/or EBV.

Source: Ruiz-Pablos M, Paiva B, Zabaleta A. Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID? J Transl Med. 2023 Sep 17;21(1):633. doi: 10.1186/s12967-023-04515-7. PMID: 37718435. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-04515-7 (Full text)

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

Highlights:

  • Plasmalogens (Pls) are lipids containing a vinyl-ether bond in their glycerol backbone.
  • Pls have antioxidant properties and are important for curved membrane assemblies.
  • Post-COVID-19 symptoms are highly prevalent and share several features with ME/CFS.
  • Pls depletion is a shared biological hallmark of ME/CFS and acute COVID-19 syndrome.
  • Pls replacement is a promising tool against neuroinflammation in these two conditions.

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.

Source: Adriano Maia Chaves-Filho, Olivia Braniff, Angelina Angelova, Yuru Deng, Marie-Ève Tremblay. 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 Research Bulletin, Volume 201, September 2023, 110702. https://www.sciencedirect.com/science/article/pii/S0361923023001272 (Full text)

WASF3 disrupts mitochondrial respiration and may mediate exercise intolerance in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by various disabling symptoms including exercise intolerance and is diagnosed in the absence of a specific cause, making its clinical management challenging. A better understanding of the molecular mechanism underlying this apparent bioenergetic deficiency state may reveal insights for developing targeted treatment strategies.

We report that overexpression of Wiskott-Aldrich Syndrome Protein Family Member 3 (WASF3), here identified in a 38-y-old woman suffering from long-standing fatigue and exercise intolerance, can disrupt mitochondrial respiratory supercomplex formation and is associated with endoplasmic reticulum (ER) stress.

Increased expression of WASF3 in transgenic mice markedly decreased their treadmill running capacity with concomitantly impaired respiratory supercomplex assembly and reduced complex IV levels in skeletal muscle mitochondria. WASF3 induction by ER stress using endotoxin, well known to be associated with fatigue in humans, also decreased skeletal muscle complex IV levels in mice, while decreasing WASF3 levels by pharmacologic inhibition of ER stress improved mitochondrial function in the cells of the patient with chronic fatigue.

Expanding on our findings, skeletal muscle biopsy samples obtained from a cohort of patients with ME/CFS showed increased WASF3 protein levels and aberrant ER stress activation. In addition to revealing a potential mechanism for the bioenergetic deficiency in ME/CFS, our study may also provide insights into other disorders associated with fatigue such as rheumatic diseases and long COVID.

Source: Wang PY, Ma J, Kim YC, Son AY, Syed AM, Liu C, Mori MP, Huffstutler RD, Stolinski JL, Talagala SL, Kang JG, Walitt BT, Nath A, Hwang PM. WASF3 disrupts mitochondrial respiration and may mediate exercise intolerance in myalgic encephalomyelitis/chronic fatigue syndrome. Proc Natl Acad Sci U S A. 2023 Aug 22;120(34):e2302738120. doi: 10.1073/pnas.2302738120. Epub 2023 Aug 14. PMID: 37579159. https://pubmed.ncbi.nlm.nih.gov/37579159/