oxidative stress – Page 5 – American ME and CFS Society

Broadband electrical impedance as a novel characterization of oxidative stress in single L6 skeletal muscle cells

Abstract:

Oxidative stress (OS) is one of the leading causes of cytotoxicity and is linked to many human physio-pathological conditions. In particular, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) induced by OS is debilitating to quality of life, while no clear biological markers have been identified for diagnostic measures. Recently, impedance measurements of peripheral blood cells of ME/CFS patients have been shown as a promising approach to diagnose the disease. Inspired by this study and aiming to interrogate muscle cells directly, we investigated if broadband measurements of single muscle cells could differentiate normal and oxidatively stressed cell populations.

We first optimized a protocol through H₂O₂ treatment to introduce oxidative stress to cultured rat L6 skeletal muscle cells. The treated cells were further characterized through broadband impedance spectroscopy of single cells using a microfluidic lab-on-a-chip system. The resulting dielectric properties of cytoplasm permittivity and conductivity are electrically distinct from normally cultured cells. The reflection and transmission coefficients, ΔS11 and ΔS21, of the normal cells are tightly clustered and closely resemble those of the cell-free solution across the frequency range of 9 kHz to 9 GHz. On the other hand, dielectric properties of the oxidized cells have a wide distribution in the GHz range, deviating both in the positive and negative directions from the normally cultured cells.

Simulation results guide our hypothesis that the dielectric differences could be linked to ion alterations, while calcium imaging directly supports the contribution of calcium flux to the observed deviation of S parameters. The unique electrical profile associated with oxidized cells in the GHz frequencies provide a framework for future development of technologies to diagnose oxidative-stress related diseases such as ME/CFS.

Source: Ferguson C, Pini N, Du X, Farina M, Hwang JMC, Pietrangelo T, Cheng X. Broadband electrical impedance as a novel characterization of oxidative stress in single L6 skeletal muscle cells. Anal Chim Acta. 2021 Aug 15;1173:338678. doi: 10.1016/j.aca.2021.338678. Epub 2021 May 25. PMID: 34172152. https://pubmed.ncbi.nlm.nih.gov/34172152/

Our Evolving Understanding of ME/CFS

Abstract:

The potential benefits of the scientific insights gleaned from years of treating ME/CFS for the emerging symptoms of COVID-19, and in particular Longhaul- or Longhauler-COVID-19 are discussed in this opinion article. Longhaul COVID-19 is the current name being given to the long-term sequelae (symptoms lasting beyond 6 weeks) of SARS-CoV-2 infection. Multiple case definitions for ME/CFS exist, but post-exertional malaise (PEM) is currently emerging as the ‘hallmark’ symptom. The inability to identify a unique trigger of ME/CFS, as well as the inability to identify a specific, diagnostic laboratory test, led many physicians to conclude that the illness was psychosomatic or non-existent. However, recent research in the US and the UK, championed by patient organizations and their use of the internet and social media, suggest underlying pathophysiologies, e.g., oxidative stress and mitochondrial dysfunction. The similarity and overlap of ME/CFS and Longhaul COVID-19 symptoms suggest to us similar pathological processes.

We put forward a unifying hypothesis that explains the precipitating events such as viral triggers and other documented exposures: For their overlap in symptoms, ME/CFS and Longhaul COVID-19 should be described as Post Active Phase of Infection Syndromes (PAPIS). We further propose that the underlying biochemical pathways and pathophysiological processes of similar symptoms are similar regardless of the initiating trigger. Exploration of the biochemical pathways and pathophysiological processes should yield effective therapies for these conditions and others that may exhibit these symptoms. ME/CFS patients have suffered far too long. Longhaul COVD-19 patients should not be subject to a similar fate. We caution that failure to meet the now combined challenges of ME/CFS and Longhaul COVID-19 will impose serious socioeconomic as well as clinical consequences for patients, the families of patients, and society as a whole.

Source: Friedman KJ, Murovska M, Pheby DFH, Zalewski P. Our Evolving Understanding of ME/CFS. Medicina (Kaunas). 2021 Feb 26;57(3):200. doi: 10.3390/medicina57030200. PMID: 33652622. https://www.mdpi.com/1648-9144/57/3/200 (Full text)

The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms

Abstract:

Oxidative stress can be induced by various stimuli and altered in certain conditions, including exercise and pain. Although many studies have investigated oxidative stress in relation to either exercise or pain, the literature presents conflicting results. Therefore, this review critically discusses existing literature about this topic, aiming to provide a clear overview of known interactions between oxidative stress, exercise, and pain in healthy people as well as in people with chronic pain, and to highlight possible confounding factors to keep in mind when reflecting on these interactions. In addition, autonomic regulation and epigenetic mechanisms are proposed as potential mechanisms of action underlying the interplay between oxidative stress, exercise, and pain.

This review highlights that the relation between oxidative stress, exercise, and pain is poorly understood and not straightforward, as it is dependent on the characteristics of exercise, but also on which population is investigated. To be able to compare studies on this topic, strict guidelines should be developed to limit the effect of several confounding factors. This way, the true interplay between oxidative stress, exercise, and pain, and the underlying mechanisms of action can be revealed and validated via independent studies.

Source: Hendrix J, Nijs J, Ickmans K, Godderis L, Ghosh M, Polli A. The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms. Antioxidants (Basel). 2020 Nov 23;9(11):1166. doi: 10.3390/antiox9111166. PMID: 33238564; PMCID: PMC7700330. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7700330/ (Full text)

Oxidative stress caused by a dysregulated Wnt/β-catenin signalling pathway is involved in abnormal placenta formation in pregnant mice with chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is characterized by extreme fatigue and disabling symptoms. Women with CFS often have a high risk of gynaecological problems such as irregular menstruation, endometriosis and pelvic pain and sexual dysfunction. Our previous results have shown that, in pregnant mice, CFS significantly decreased the progestational hormone level in serum, as well as learning and memory, and the function of the hypothalamus-pituitary-gonadal axis. In addition, the F1 generation also suffered from congenital hypothyroidism. At present, there has been no report about placenta formation and embryonic development in pregnant mice with CFS. The aim of the present study was to investigate the influence of CFS on the morphology, oxidative stress and Wnt/β-catenin signalling pathway during placenta formation.

In this study, we found that CFS decreased the number of implantation sites for blastocysts, and increased the number of absorbed, stillborn and malformed fetuses. The morphology and structure of the placenta were abnormal in pregnant mice with CFS. Further study found that the oxidative stress in serum, uterus and placenta was increased in pregnant mice with CFS, while the levels of antioxidase were decreased. CFS also inhibited the Wnt/β-catenin signalling pathway in the placenta. These results suggested that inhibition of the Wnt/β-catenin signalling pathway and enhanced oxidative stress play an important role in abnormal placentation in pregnant mice with CFS.

Source: Zhao H, Zhang J, Qian N, Wu S, Wu Y, Yao G. Oxidative stress caused by a dysregulated Wnt/β-catenin signalling pathway is involved in abnormal placenta formation in pregnant mice with chronic fatigue syndrome. Zygote. 2020 Oct 15:1-8. doi: 10.1017/S096719942000057X. Epub ahead of print. PMID: 33054899. https://pubmed.ncbi.nlm.nih.gov/33054899/

A SWATH-MS analysis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome peripheral blood mononuclear cell proteomes reveals mitochondrial dysfunction

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a serious and complex physical illness that affects all body systems with a multiplicity of symptoms, but key hallmarks of the disease are pervasive fatigue and ‘post-exertional malaise’, exacerbation after physical and/or mental activity of the intrinsic fatigue and other symptoms that can be highly debilitating and last from days to months. Although the disease can vary widely between individuals, common symptoms also include pain, cognitive deficits, sleep dysfunction, as well as immune, neurological and autonomic symptoms. Typically, it is a very isolating illness socially, carrying a stigma because of the lack of understanding of the cause and pathophysiology.

Methods: To gain insight into the pathophysiology of ME/CFS, we examined the proteomes of peripheral blood mononuclear cells (PBMCs) by SWATH-MS analysis in a small well-characterised group of patients and matched controls. A principal component analysis (PCA) was used to stratify groups based on protein abundance patterns, which clearly segregated the majority of the ME/CFS patients (9/11) from the controls. This majority subgroup of ME/CFS patients was then further compared to the control group.

Results: A total of 60 proteins in the ME/CFS patients were differentially expressed (P < 0.01, Log10 (Fold Change) > 0.2 and < -0.2). Comparison of the PCA selected subgroup of ME/CFS patients (9/11) with controls increased the number of proteins differentially expressed to 99. Of particular relevance to the core symptoms of fatigue and post-exertional malaise experienced in ME/CFS, a proportion of the identified proteins in the ME/CFS groups were involved in mitochondrial function, oxidative phosphorylation, electron transport chain complexes, and redox regulation. A significant number were also involved in previously implicated disturbances in ME/CFS, such as the immune inflammatory response, DNA methylation, apoptosis and proteasome activation.

Conclusions: The results from this study support a model of deficient ATP production in ME/CFS, compensated for by upregulation of immediate pathways upstream of Complex V that would suggest an elevation of oxidative stress. This study and others have found evidence of a distinct pathology in ME/CFS that holds promise for developing diagnostic biomarkers.

Source: Sweetman E, Kleffmann T, Edgar C, de Lange M, Vallings R, Tate W. A SWATH-MS analysis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome peripheral blood mononuclear cell proteomes reveals mitochondrial dysfunction. J Transl Med. 2020 Sep 24;18(1):365. doi: 10.1186/s12967-020-02533-3. PMID: 32972442. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-020-02533-3 (Full text)

Environmental, Neuro-immune, and Neuro-oxidative Stress Interactions in Chronic Fatigue Syndrome

Abstract:

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS) is a complex, multisystem disease that is characterized by long-term fatigue, exhaustion, disabilities, pain, neurocognitive impairments, gastrointestinal symptoms, and post-exertional malaise, as well as lowered occupational, educational, and social functions. The clinical and biomarker diagnosis of this disorder is hampered by the lack of validated diagnostic criteria and laboratory tests with adequate figures of merit, although there are now many disease biomarkers indicating the pathophysiology of CFS.

Here, we review multiple factors, such as immunological and environmental factors, which are associated with CFS and evaluate current concepts on the involvement of immune and environmental factors in the pathophysiology of CFS. The most frequently reported immune dysregulations in CFS are modifications in immunoglobulin contents, changes in B and T cell phenotypes and cytokine profiles, and decreased cytotoxicity of natural killer cells. Some of these immune aberrations display a moderate diagnostic performance to externally validate the clinical diagnosis of CFS, including the expression of activation markers and protein kinase R (PKR) activity. Associated with the immune aberrations are activated nitro-oxidative pathways, which may explain the key symptoms of CFS.

This review shows that viral and bacterial infections, as well as nutritional deficiencies, may further aggravate the immune-oxidative pathophysiology of CFS. Targeted treatments with antioxidants and lipid replacement treatments may have some clinical efficacy in CFS. We conclude that complex interactions between immune and nitro-oxidative pathways, infectious agents, environmental factors, and nutritional deficiencies play a role in the pathophysiology of CFS.

Source: Bjørklund G, Dadar M, Pivina L, Doşa MD, Semenova Y, Maes M. Environmental, Neuro-immune, and Neuro-oxidative Stress Interactions in Chronic Fatigue Syndrome [published online ahead of print, 2020 Aug 6]. Mol Neurobiol. 2020;10.1007/s12035-020-01939-w. doi:10.1007/s12035-020-01939-w https://pubmed.ncbi.nlm.nih.gov/32761353/

Neuroinflammation, Oxidative Stress, and Neurogenesis in a Mouse Model of Chronic Fatigue Syndrome, and the Treatment with Kampo Medicine

Abstract:

The diagnosis of chronic fatigue syndrome (CFS) is mainly symptom-based, and the etiology is still unclear. Here, we evaluated the pathological changes in the brain of a mouse model of CFS and studied the effects of Kampo medicine.

A mouse model of CFS was established through six repeated injections of Brucella abortus (BA) every two weeks for a period of 12 weeks. Neuroinflammation was measured by estimating interleukin (IL)-1β, IL-6, and interferon-gamma (IFN-γ), and oxidative stress by nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE) 6 weeks after the last injection. Hippocampal neurogenesis was evaluated through Ki-67, doublecortin (DCX), and 5-bromodeoxyuridine (BrdU) assays. The effects of Kampo medicines (Hochuekkito (TJ-41) and Hachimijiogan (TJ-7)) on neuroinflammation during CFS were studied.

The wheel-running activity of mice was decreased by about 50% compared to baseline at 6 weeks after the last BA injection. The levels of IL-1β, IL-6, 3-NT, and 4-HNE were increased in both the cortex and the hippocampus of CFS mice at 6 weeks after the last BA injection. Hippocampal neurogenesis was unchanged in CFS mice. Treatment with TJ-41 and TJ-7 reduced the expressions of IL-1β, IL-6, and IFN-γ in the hippocampus but not in the cortex.

The results of the present study indicate that neuroinflammation and oxidative stress play important roles in the pathogenesis of CFS. The data further suggest that treatment with TJ-41 and TJ-7 could help reduce the inflammation associated with CFS in the hippocampus, but failed to improve the symptoms in CFS mice.

Source: He Q, Sawada M, Yamasaki N, Akazawa S, Furuta H, Uenishi H, Meng X, Nakahashi T, Ishigaki Y, Moriya J. Neuroinflammation, Oxidative Stress, and Neurogenesis in a Mouse Model of Chronic Fatigue Syndrome, and the Treatment with Kampo Medicine. Biol Pharm Bull. 2020;43(1):110-115. doi: 10.1248/bpb.b19-00616. https://www.jstage.jst.go.jp/article/bpb/43/1/43_b19-00616/_article (Full article)

Understanding neuromuscular disorders in chronic fatigue syndrome

Abstract:

Muscle failure has been demonstrated in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Neurophysiological tools demonstrate the existence of both central and peripheral fatigue in these patients. Central fatigue is deduced from the reduced amplitude of myopotentials evoked by transcranial magnetic stimulation of the motor cortex as well as by the muscle response to interpolated twitches during sustained fatiguing efforts. An impaired muscle membrane conduction velocity assessed by the reduced amplitude and lengthened duration of myopotentials evoked by direct muscle stimulation is the defining feature of peripheral fatigue.

Some patients with ME/CFS show an increased oxidative stress response to exercise. The formation of lipid hydroperoxides in the sarcolemma, which alters ionic fluxes, could explain the reduction of muscle membrane excitability and potassium outflow often measured in these patients. In patients with ME/CFS, the formation of heat shock proteins (HSPs) is also reduced. Because HSPs protect muscle cells against the deleterious effects of reactive oxygen species, the lack of their production could explain the augmented oxidative stress and the consecutive alterations of myopotentials which could open a way for future treatment of ME/CFS.

Source: Jammes Y, Retornaz F. Understanding neuromuscular disorders in chronic fatigue syndrome.F1000Res. 2019 Nov 28;8. pii: F1000 Faculty Rev-2020. doi: 10.12688/f1000research.18660.1. eCollection 2019. https://www.ncbi.nlm.nih.gov/pubmed/31814961

Oxidative Stress is a Convincing Contributor to Idiopathic Chronic Fatigue

Abstract:

The linkage between oxidative stress and idiopathic chronic fatigue (ICF) has not been explored in detail. This study thoroughly compared the serum levels of biomarkers for oxidative stress and antioxidants from 103 subjects with ICF (20 men and 83 women) to those of 82 healthy volunteers (27 men and 55 women).

Oxidative parameters, which included reactive oxygen species (ROS), malondialdehyde (MDA) and F2-isoprotan, and tumor necrosis factor-alpha (TNF-α) were significantly elevated, while antioxidant parameters, which included total antioxidant activity (TAC), catalase, superoxide dismutase, SOD and GSH activity, were decreased compared to those of healthy subjects (by approximately 1.2- to 2.3-fold, p < 0.05 or 0.01).

Our results confirmed that oxidative stress is a key contributor in the pathophysiology of ICF, and firstly explored the features of oxidative stress parameters in ICF subjects compared to a healthy population.

Source: Lee JS, Kim HG, Lee DS, Son CG. Oxidative Stress is a Convincing Contributor to Idiopathic Chronic Fatigue. Sci Rep. 2018;8(1):12890. Published 2018 Aug 27. doi:10.1038/s41598-018-31270-3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6110864/ (Full article)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: From Pathophysiological Insights to Novel Therapeutic Opportunities

Abstract:

Myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) is a common and disabling condition with a paucity of effective and evidence-based therapies reflecting a major unmet need. Cognitive behavioural therapy and graded exercise are of modest benefit for only some ME/CFS patients, and many sufferers report aggravation of symptoms of fatigue with exercise.

The presence of a multiplicity of pathophysiological abnormalities, in at least the subgroup of people with ME/CFS diagnosed with the current international consensus “Fukuda” criteria, points to numerous potential therapeutic targets. Such abnormalities include extensive data showing that at least a subgroup has a pro-inflammatory state, increased oxidative and nitrosative stress, disruption of gut mucosal barriers and mitochondrial dysfunction together with dysregulated bioenergetics.

In this paper, these pathways are summarised, and data regarding promising therapeutic options that target these pathways are highlighted; they include coenzyme Q10, melatonin, curcumin, molecular hydrogen and N-acetylcysteine. These data are promising yet preliminary, suggesting hopeful avenues to address this major unmet burden of illness.

Source: Morris G, Puri BK, Walker AJ, Maes M, Carvalho AF, Walder K, Mazza C, Berk M. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: From Pathophysiological Insights to Novel Therapeutic Opportunities. Pharmacol Res. 2019 Sep 8:104450. doi: 10.1016/j.phrs.2019.104450. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31509764