Tag: review

Proposed subtypes of post-COVID-19 syndrome (or long-COVID) and their respective potential therapies

Abstract:

The effects of coronavirus disease 2019 (COVID-19), a highly transmissible infectious respiratory disease that has initiated an ongoing pandemic since early 2020, do not always end in the acute phase. Depending on the study referred, about 10%-30% (or more) of COVID-19 survivors may develop long-COVID or post-COVID-19 syndrome (PCS), characterised by persistent symptoms (most commonly fatigue, dyspnoea, and cognitive impairments) lasting for 3 months or more after acute COVID-19. While the pathophysiological mechanisms of PCS have been extensively described elsewhere, the subtypes of PCS have not. Owing to its highly multifaceted nature, this review proposes and characterises six subtypes of PCS based on the existing literature.

The subtypes are non-severe COVID-19 multi-organ sequelae (NSC-MOS), pulmonary fibrosis sequelae (PFS), myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), postural orthostatic tachycardia syndrome (POTS), post-intensive care syndrome (PICS) and medical or clinical sequelae (MCS). Original studies supporting each of these subtypes are documented in this review, as well as their respective symptoms and potential interventions. Ultimately, the subtyping proposed herein aims to provide better clarity on the current understanding of PCS.

Source: Yong SJ, Liu S. Proposed subtypes of post-COVID-19 syndrome (or long-COVID) and their respective potential therapies. Rev Med Virol. 2021 Dec 9:e2315. doi: 10.1002/rmv.2315. Epub ahead of print. PMID: 34888989. https://pubmed.ncbi.nlm.nih.gov/34888989/

Epstein-Barr Virus and the Origin of Myalgic Encephalomyelitis or Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) affects approximately 1% of the general population. It is a chronic, disabling, multi-system disease for which there is no effective treatment. This is probably related to the limited knowledge about its origin. Here, we summarized the current knowledge about the pathogenesis of ME/CFS and revisit the immunopathobiology of Epstein-Barr virus (EBV) infection. Given the similarities between EBV-associated autoimmune diseases and cancer in terms of poor T cell surveillance of cells with EBV latency, expanded EBV-infected cells in peripheral blood and increased antibodies against EBV, we hypothesize that there could be a common etiology generated by cells with EBV latency that escape immune surveillance.

Albeit inconclusive, multiple studies in patients with ME/CFS have suggested an altered cellular immunity and augmented Th2 response that could result from mechanisms of evasion to some pathogens such as EBV, which has been identified as a risk factor in a subset of ME/CFS patients. Namely, cells with latency may evade the immune system in individuals with genetic predisposition to develop ME/CFS and in consequence, there could be poor CD4 T cell immunity to mitogens and other specific antigens, as it has been described in some individuals.

Ultimately, we hypothesize that within ME/CFS there is a subgroup of patients with DRB1 and DQB1 alleles that could confer greater susceptibility to EBV, where immune evasion mechanisms generated by cells with latency induce immunodeficiency. Accordingly, we propose new endeavors to investigate if anti-EBV therapies could be effective in selected ME/CFS patients.

Source: Ruiz-Pablos M, Paiva B, Montero-Mateo R, Garcia N, Zabaleta A. Epstein-Barr Virus and the Origin of Myalgic Encephalomyelitis or Chronic Fatigue Syndrome. Front Immunol. 2021 Nov 15;12:656797. doi: 10.3389/fimmu.2021.656797. PMID: 34867935; PMCID: PMC8634673. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8634673/ (Full text)

ME/CFS and the biopsychosocial model: a review of patient harm and distress in the medical encounter

Abstract:

Objective: Despite the growing evidence of physiological and cellular abnormalities in myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS), there has been a strong impetus to tackle the illness utilizing a biopsychosocial model. However, many sufferers of this disabling condition report distress and dissatisfaction following medical encounters. This review seeks to account for this discord.

Methods: A narrative review methodology is employed to synthesize the evidence for potential iatrogenesis.

Results: We identify seven potential modalities of iatrogenesis or harm reported by patients: difficulties in reaching an acceptable diagnosis; misdiagnosis, including of other medical and psychological conditions; difficulties in accessing the sick role, medical care and social support; high levels of patient dissatisfaction with the quality of medical care; negative responses to controversial therapies (cognitive behavioral therapy and graded exercise therapy); challenges to the patient narrative and experience; psychological harm (individual and collective distress).

Conclusion: The biopsychosocial framework currently applied to ME/CFS is too narrow in focus and fails to adequately incorporate the patient narrative. Misdiagnosis, conflict, and harm are observable outcomes where doctors’ and patients’ perspectives remain incongruent. Biopsychosocial practices should be scrutinized for potential harms. Clinicians should consider adopting alternative patient-centred approaches.

Implications for rehabilitation: Patients with ME/CFS may report or experience one or more of the modalities of harms and distress identified in this review. It is important health and rehabilitation professionals seek to avoid and minimize harms when treating or assisting ME/CFS patients. There are conflicting models of ME/CFS; we highlight two divergent models, a biopsychosocial model and a biomedical model that is preferred by patients. The ‘biopsychosocial framework’ applied in clinical practice promotes treatments such as cognitive behavioral therapy and exercise therapy, however, the evidence for their success is contested and many patients reject the notion their illness is perpetuated by dysfunctional beliefs, personality traits, or behaviors. Health professionals may avoid conflict and harm causation in ME/CFS by adopting more concordant ‘patient-centred’ approaches that give greater prominence to the patient narrative and experience of illness.

Source: Geraghty KJ, Blease C. Myalgic encephalomyelitis/chronic fatigue syndrome and the biopsychosocial model: a review of patient harm and distress in the medical encounter. Disabil Rehabil. 2019 Dec;41(25):3092-3102. doi: 10.1080/09638288.2018.1481149. Epub 2018 Jun 21. PMID: 29929450. https://pubmed.ncbi.nlm.nih.gov/29929450/

The role of mitochondria in ME/CFS: a perspective

Abstract:

Chronic fatigue syndrome (CFS) also known as Myalgic encephalomyelitis (ME) is a debilitating disease, characterized by the symptom of severe fatigue. ME/CFS is a heterogeneous condition in both clinical presentation and disease duration. A diagnosis of ME/CFS is based on the exclusion of other diseases due to a current lack of known biomarkers for the disease. Patients may be split into categories based on the severity of their illness – mild, moderate and severe. Here we consider some of the recent advances in the understanding of mitochondrial dysfunction and mitochondrial DNA (mtDNA) variation that may have relevance to ME/CFS.

Thus far, we have shown that ME/CFS patients do not harbor proven mtDNA mutations, another exclusion, albeit an important one. As such this group of patients do not fall within the category of patients with mitochondrial disorder. If ME/CFS patients have some form of mitochondrial dysfunction, the form and cause of this dysfunction is a matter of debate. The current data underlines the need to move from small studies to larger endeavors applying multiple methods to well-defined cohorts with samples taken longitudinally.

Source: Cara Tomas & Joanna L Elson (2019) The role of mitochondria in ME/CFS: a perspective, Fatigue: Biomedicine, Health & Behavior, 7:1, 52-58, DOI: 10.1080/21641846.2019.1580855 https://www.tandfonline.com/doi/abs/10.1080/21641846.2019.1580855  (Full text)

Skeletal muscle alterations in patients with acute Covid-19 and post-acute sequelae of Covid-19

Abstract:

Background and methods: Skeletal muscle-related symptoms are common in both acute Covid-19 and Post-Acute Sequelae of Covid-19 (PASC). In this narrative review, we discuss cellular and molecular pathways that are affected, and consider these in regard to skeletal muscle involvement in other conditions, such as acute respiratory distress syndrome, critical illness myopathy and post-viral fatigue syndrome.
Results: Patients with severe Covid-19 and PASC suffer from skeletal muscle weakness and exercise intolerance. Histological sections present muscle fiber atrophy, metabolic alterations, and immune cell infiltration. Contributing factors to weakness and fatigue in patients with severe Covid-19 include systemic inflammation, disuse, hypoxemia, and malnutrition. These factors also contribute to post-ICU syndrome and ICU-acquired weakness, and likely explain a substantial part of Covid-19-acquired weakness. The skeletal muscle weakness and exercise intolerance associated with PASC are more obscure and different factors likely contribute. Direct SARS-CoV-2 viral infiltration into skeletal muscle or an aberrant immune system likely contribute. Similarities between skeletal muscle alterations in PASC and chronic fatigue syndrome deserve further study.
Conclusion: Both SARS-CoV-2 specific factors and generic consequences of acute disease likely underlie the observed skeletal muscle alterations in both acute Covid 19 and PASC.
Source: Soares, M., Eggelbusch, M., Naddaf, E., Gerrits, K., van der Schaaf, M., van den Borst, B., Wiersinga, W. J., et al. Skeletal muscle alterations in patients with acute Covid-19 and post-acute sequelae of Covid-19. Journal of Cachexia, Sarcopenia and Muscle. https://doi.org/10.17863/CAM.78509 https://www.repository.cam.ac.uk/handle/1810/331064

Back to the Future? Immunoglobulin Therapy for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

The findings of controlled trials on use of intravenous immunoglobulin G (IV IgG) to treat myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are generally viewed as representing mixed results. On detailed review, a clearer picture emerges, which suggests that the potential therapeutic value of this intervention has been underestimated.

Our analysis is consistent with the propositions that: (1) IgG is highly effective for a proportion of patients with severe and well-characterised ME/CFS; (2) responders can be predicted with a high degree of accuracy based on markers of immune dysfunction. Rigorous steps were taken in the research trials to record adverse events, with transient symptom exacerbation commonly experienced in both intervention and placebo control groups, suggesting that this reflected the impact of participation on people with an illness characterised by post-exertional symptom exacerbation. Worsening of certain specific symptoms, notably headache, did occur more commonly with IgG and may have been concomitant to effective treatment, being associated with clinical improvement.

The findings emerging from this review are supported by clinical observations relating to treatment of patients with severe and very severe ME/CFS, for whom intramuscular and subcutaneous administration provide alternative options. We conclude that: (1) there is a strong case for this area of research to be revived; (2) pending further research, clinicians would be justified in offering a course of IgG to selected ME/CFS patients at the more severe end of the spectrum. As the majority of trial participants had experienced an acute viral or viral-like onset, we further suggest that IgG treatment may be pertinent to the care of some patients who remain ill following infection with SARS-CoV-2 virus.

Source: Brownlie H, Speight N. Back to the Future? Immunoglobulin Therapy for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Healthcare (Basel). 2021 Nov 12;9(11):1546. doi: 10.3390/healthcare9111546. PMID: 34828592. https://pubmed.ncbi.nlm.nih.gov/34828592/

The Emerging Role of Gut Microbiota in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Current Evidence and Potential Therapeutic Applications

Abstract:

The well-known symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) are chronic pain, cognitive dysfunction, post-exertional malaise and severe fatigue. Another class of symptoms commonly reported in the context of ME/CFS are gastrointestinal (GI) problems. These may occur due to comorbidities such as Crohn’s disease or irritable bowel syndrome (IBS), or as a symptom of ME/CFS itself due to an interruption of the complex interplay between the gut microbiota (GM) and the host GI tract. An altered composition and overall decrease in diversity of GM has been observed in ME/CFS cases compared to controls. In this review, we reflect on genetics, infections, and other influences that may factor into the alterations seen in the GM of ME/CFS individuals, we discuss consequences arising from these changes, and we contemplate the therapeutic potential of treating the gut to alleviate ME/CFS symptoms holistically.

Source: Varesi A, Deumer US, Ananth S, Ricevuti G. The Emerging Role of Gut Microbiota in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Current Evidence and Potential Therapeutic Applications. J Clin Med. 2021 Oct 29;10(21):5077. doi: 10.3390/jcm10215077. PMID: 34768601. https://pubmed.ncbi.nlm.nih.gov/34768601/

Potential Implications of Mammalian Transient Receptor Potential Melastatin 7 in the Pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Review

Abstract:

The transient receptor potential (TRP) superfamily of ion channels is involved in the molecular mechanisms that mediate neuroimmune interactions and activities. Recent advancements in neuroimmunology have identified a role for TRP cation channels in several neuroimmune disorders including amyotropic lateral sclerosis, multiple sclerosis, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS is a debilitating disorder with an obscure aetiology, hence considerable examination of its pathobiology is warranted. Dysregulation of TRP melastatin (TRPM) subfamily members and calcium signalling processes are implicated in the neurological, immunological, cardiovascular, and metabolic impairments inherent in ME/CFS.

In this review, we present TRPM7 as a potential candidate in the pathomechanism of ME/CFS, as TRPM7 is increasingly recognized as a key mediator of physiological and pathophysiological mechanisms affecting neurological, immunological, cardiovascular, and metabolic processes. A focused examination of the biochemistry of TRPM7, the role of this protein in the aforementioned systems, and the potential of TRPM7 as a molecular mechanism in the pathophysiology of ME/CFS will be discussed in this review. TRPM7 is a compelling candidate to examine in the pathobiology of ME/CFS as TRPM7 fulfils several key roles in multiple organ systems, and there is a paucity of literature reporting on its role in ME/CFS.

Source: Du Preez S, Cabanas H, Staines D, Marshall-Gradisnik S. Potential Implications of Mammalian Transient Receptor Potential Melastatin 7 in the Pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Review. Int J Environ Res Public Health. 2021 Oct 12;18(20):10708. doi: 10.3390/ijerph182010708. PMID: 34682454; PMCID: PMC8535478. https://pubmed.ncbi.nlm.nih.gov/34682454/ (Full text)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A neurological entity?

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disorder of unknown physiopathology with multisystemic repercussions, framed in ICD-11 under the heading of neurology (8E49). There is no specific test to support its clinical diagnosis. Our objective is to review the evidence in neuroimaging and dysautonomia evaluation in order to support the neurological involvement and to find biomarkers serving to identify and/or monitor the pathology.
The symptoms typically appear acutely, although they can develop progressively over years; an essential trait for diagnosis is “central” fatigue together with physical and/or mental exhaustion after a small effort. Neuroimaging reveals various morphological, connectivity, metabolic, and functional alterations of low specificity, which can serve to complement the neurological study of the patient. The COMPASS-31 questionnaire is a useful tool to triage patients under suspect of dysautonomia, at which point they may be redirected for deeper evaluation. Recently, alterations in heart rate variability, the Valsalva maneuver, and the tilt table test, together with the presence of serum autoantibodies against adrenergic, cholinergic, and serotonin receptors were shown in a subgroup of patients.
This approach provides a way to identify patient phenotypes. Broader studies are needed to establish the level of sensitivity and specificity necessary for their validation. Neuroimaging contributes scarcely to the diagnosis, and this depends on the identification of specific changes. On the other hand, dysautonomia studies, carried out in specialized units, are highly promising in order to support the diagnosis and to identify potential biomarkers. ME/CFS orients towards a functional pathology that mainly involves the autonomic nervous system, although not exclusively.
Source: Gandasegui IM, Laka LA, Gargiulo P-Á, Gómez-Esteban J-C, Sánchez J-VL. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Neurological Entity? Medicina. 2021; 57(10):1030. https://doi.org/10.3390/medicina57101030 https://www.mdpi.com/1648-9144/57/10/1030 (Full article available as PDF file)

Induced pluripotent stem cells as suitable sensors for fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: Fibromyalgia (FM) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are devastating metabolic neuroimmune diseases that are difficult to diagnose because of the presence of numerous symptoms and a lack of specific biomarkers. Despite patient heterogeneity linked to patient subgroups and variation in disease severity, anomalies are found in the blood and plasma of these patients when compared with healthy control groups. The seeming specificity of these “plasma factors”, as recently reported by Ron Davis and his group at Stanford University, CA, United States, and observations by our group, have led to the proposal that induced pluripotent stem cells (iPSCs) may be used as metabolic sensors for FM and ME/CFS, a hypothesis that is the basis for this in-depth review.

Aim: To identify metabolic signatures in FM and/or ME/CFS supporting the existence of disease-associated plasma factors to be sensed by iPSCs.

Methods: A PRISMA (Preferred Reported Items for Systematic Reviews and Meta-analysis)-based systematic review of the literature was used to select original studies evaluating the metabolite profiles of FM and ME/CFS body fluids. The MeSH terms “metabolomic” or “metabolites” in combination with FM and ME/CFS disease terms were screened against the PubMed database. Only original studies applying omics technologies, published in English, were included. The data obtained were tabulated according to the disease and type of body fluid analyzed. Coincidences across studies were searched and P-values reported by the original studies were gathered to document significant differences found in the disease groups.

Results: Eighteen previous studies show that some metabolites are commonly altered in ME/CFS and FM body fluids. In vitro cell-based assays have the potential to be developed as screening platforms, providing evidence for the existence of factors in patient body fluids capable of altering morphology, differentiation state and/or growth patterns. Moreover, they can be further developed using approaches aimed at blocking or reversing the effects of specific plasma/serum factors seen in patients. The documented high sensitivity and effective responses of iPSCs to environmental cues suggests that these pluripotent cells could form robust, reproducible reporter systems of metabolic diseases, including ME/CFS and FM. Furthermore, culturing iPSCs, or their mesenchymal stem cell counterparts, in patient-conditioned medium may provide valuable information to predict individual outcomes to stem-cell therapy in the context of precision medicine studies.

Conclusion: This opinion review explains our hypothesis that iPSCs could be developed as a screening platform to provide evidence of a metabolic imbalance in FM and ME/CFS.

Source: Monzón-Nomdedeu MB, Morten KJ, Oltra E. Induced pluripotent stem cells as suitable sensors for fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome. World J Stem Cells. 2021 Aug 26;13(8):1134-1150. doi: 10.4252/wjsc.v13.i8.1134. PMID: 34567431; PMCID: PMC8422931. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8422931/ (Full article)