Metabolism in chronic fatigue syndrome

The effect of biocide chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) mixture on C2C12 muscle cell damage attributed to mitochondrial reactive oxygen species overproduction and autophagy activation

The mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (CMIT/MIT) is a biocide widely used as a preservative in various commercial products. This biocide has also been used as an active ingredient in humidifier disinfectants in South Korea, resulting in serious health effects among users. Recent evidence suggests that the underlying mechanism of CMIT/MIT-initiated toxicity might be associated with defects in mitochondrial functions. The aim of this study was to utilize the C2C12 skeletal muscle model to investigate the effects of CMIT/MIT on mitochondrial function and relevant molecular pathways associated with skeletal muscle dysfunction. Data demonstrated that exposure to CMIT/MIT during myogenic differentiation induced significant mitochondrial excess production of reactive oxygen species (ROS) and a decrease in intracellular ATP levels. Notably, CMIT/MIT significantly inhibited mitochondrial oxidative phosphorylation (Oxphos) and reduced mitochondrial mass at a lower concentration than the biocide amount, which diminished the viability of myotubes. CMIT/MIT induced activation of autophagy flux and decreased protein expression levels of myosin heavy chain (MHC). Taken together, CMIT/MIT exposure produced damage in C2C12 myotubes by impairing mitochondrial bioenergetics and activating autophagy. Our findings contribute to an increased understanding of the underlying mechanisms associated with CMIT/MIT-induced adverse skeletal muscle health effects.

Lower hair cortisol concentration in adolescent and young adult patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Q-Fever Fatigue Syndrome compared to controls

BACKGROUND

In patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), momentary cortisol concentrations in blood, urine, and saliva are lower compared to healthy controls. Long-term cortisol concentration can be assessed through hair, but it is unclear whether these concentrations are also lower. Additionally, it is unknown if lower cortisol extends to other patients suffering from persistent fatigue and how hair cortisol concentration (HCC) relates to fatigue levels. Therefore, this study examines HCC in fatigued patients with ME/CFS, Q fever Fatigue Syndrome (QFS), Post-COVID-19 condition (PCC), and Juvenile Idiopathic Arthritis (JIA).

METHODS

Adolescent and young adult patients with ME/CFS (n=12), QFS (n=20), PCC (n=8), JIA (n=19), and controls (n=57) were included. Patients participated in a randomized cross-over trial (RCT) targeting fatigue through lifestyle and dietary self-management strategies. HCC was measured pre-post RCT in patients and once in controls, quantified using a LC-MS/MS-based method. Fatigue severity was measured with the Checklist Individual Strength-8. HCC was compared between groups with ANOVAs. Relations between HCC, fatigue severity, and other variables were investigated using linear regression analyses.

RESULTS

The ME/CFS (p=.009) and QFS (p=.047) groups had lower HCC compared to controls. Overall, HCC was negatively associated with the presence of symptoms related to chronic fatigue syndromes (e.g., sleeping issues, often feeling tired, trouble thinking clearly; β=-0.018, p=.035), except in the QFS group (β=.063, p<.001). Baseline HCC did not predict fatigue improvement during the RCT (p=.449), and HCC increased during the trial (Mdif=.076, p=.021) regardless of clinically relevant fatigue improvement (p=.658).

CONCLUSION

Lower cortisol concentration can also be observed in the long-term. Lower HCC is not limited to ME/CFS, as it was also observed in QFS. The role of cortisol may differ between these diagnoses and appears to be unrelated to fatigue levels.

Chronic Fatigue Syndrome: Diagnosis, Treatment, and Future Direction

Myalgic encephalomyelitis (ME), also known as chronic fatigue syndrome (CFS), is a complex, chronic condition marked by persistent, debilitating fatigue that is not alleviated by rest and often worsens with physical or mental exertion. Along with fatigue, patients experience various symptoms, including cognitive impairments, post-exertional malaise, muscle and joint pain, sleep disturbances, and immune system dysfunction. Diagnosing CFS/ME is challenging due to the absence of definitive biomarkers, the overlap of symptoms with other conditions, and the lack of standardized diagnostic criteria. This comprehensive literature review aims to contribute to the understanding of CFS/ME, including its diagnosis, pathophysiology, differential diagnosis, treatment, and future directions.

Integrated time-series biochemical, transcriptomic, and metabolomic analyses reveal key metabolites and signaling pathways in the liver of the Chinese soft-shelled turtle (Pelodiscus sinensis) against Aeromonas hydrophila infection

Introduction

Aeromonas hydrophila, a bacterium widely distributed in the natural environment, causes multiple diseases in various animals. Exploring the mechanism of the host defense against A. hydrophila can help develop efficient strategies against Aeromonas infection.

Methods

Herein, we investigated the temporal influence of A. hydrophila on the Chinese soft-shelled turtle, an economically important species, at the biochemical, transcriptomic, and metabolomic levels. Plasma parameters were detected with the test kits. Transcriptome and metabolome were respectively applied to screen the differentially expressed genes and metabolites.

Results

The contents or activities of these plasma parameters were significantly increased at 24 hpi and declined at 96 hpi, indicating that 24 and 96 hpi were two important time points during infection. Totals of 3121 and 274 differentially expressed genes (DEGs) from the transcriptome while 74 and 91 differentially abundant metabolites (DAMs) from the metabolome were detected at 24 and 96 hpi. The top DEGs at 24 hpi included Ccl2, Ccl3, Ccl4, Il1β, Il6, Il7, Il15, Tnf, and Tnfr1 while Zap70, Cd3g, Cd8a, Itk, Pik3r3, Cd247, Malt1, and Cd4 were the most abundant at 96 hpi. The predominant DAMs included O-phospho-L-serine, γ-Aminobutyric acid, orotate, L-tyrosine, and L-tryptophan at 24 hpi, as well as L-glutamic acid, L-arginine, glutathione, glutathione disulfide, and citric acid at 96 hpi.

Discussion

The combined analysis of DEGs and DAMs revealed that tryptophan metabolism, nicotinate and nicotinamide metabolism, as well as starch and sucrose metabolism, were the most important signaling pathways at the early infective stage while tyrosine metabolism, pyrimidine metabolism, as well as alanine, aspartate and glutamate metabolism were the most crucial pathways at the later stage. In general, our results indicated that the Chinese soft-shelled turtle displays stage-specific physiological responses to resist A. hydrophila infection.

Chronic Overlapping Pain Conditions and Nociplastic Pain

Chronic Overlapping Pain Conditions (COPCs) are a subset of chronic pain conditions commonly comorbid with one another and more prevalent in women and assigned female at birth (AFAB) individuals. Pain experience in these conditions may better fit with a new mechanistic pain descriptor, nociplastic pain, and nociplastic type pain may represent a shared underlying factor among COPCs. We applied GenomicSEM common-factor genome wide association study (GWAS) and multivariate transcriptome-wide association (TWAS) analyses to existing GWAS output for six COPCs in order to find genetic variation associated with nociplastic type pain, followed by genetic correlation (linkage-disequilibrium score regression), gene-set and tissue enrichment analyses. We found 24 independent single nucleotide polymorphisms (SNPs), and 127 unique genes significantly associated with nociplastic type pain, and showed nociplastic type pain to be a polygenic trait with significant SNP-heritability. We found significant genetic overlap between multisite chronic pain and nociplastic type pain, and to a smaller extent with rheumatoid arthritis and a neuropathic pain phenotype. Tissue enrichment analyses highlighted cardiac and thyroid tissue, and gene set enrichment analyses emphasized potential shared mechanisms in cognitive, personality, and metabolic traits and nociplastic type pain along with distinct pathology in migraine and headache. We use a well-powered network approach to investigate nociplastic type pain using existing COPC GWAS output, and show nociplastic type pain to be a complex, heritable trait, in addition to contributing to understanding of potential mechanisms in development of nociplastic pain.

Identification of CD8 T-cell dysfunction associated with symptoms in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID and treatment with a nebulized antioxidant/anti-pathogen agent in a retrospective case series

Background

Patients with post-acute sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (PASC, i.e., Long COVID) have a symptom complex highly analogous to many features of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), suggesting they may share some aspects of pathogenesis in these similar disorders. ME/CFS is a complex disease affecting numerous organ systems and biological processes and is often preceded by an infection-like episode. It is postulated that the chronic manifestations of illness may result from an altered host response to infection or inability to resolve inflammation, as is being reported in Long COVID. The immunopathogenesis of both disorders is still poorly understood. Here, we show data that suggest Long COVID and ME/CFS may be due to an aberrant response to an immunological trigger-like infection, resulting in a dysregulated immune system with CD8 T-cell dysfunction reminiscent of some aspects of T-cell clonal exhaustion, a phenomenon associated with oxidative stress. As there is an urgent need for diagnostic tools and treatment strategies for these two related disabling disorders, here, in a retrospective case series, we have also identified a potential nebulized antioxidant/anti-pathogen treatment that has evidence of a good safety profile. This nebulized agent is comprised of five ingredients previously reported individually to relieve oxidative stress, attenuate NF-κB signaling, and/or to act directly to inhibit pathogens, including viruses. Administration of this treatment by nebulizer results in rapid access of small doses of well-studied antioxidants and agents with anti-pathogen potential to the lungs; components of this nebulized agent are also likely to be distributed systemically, with potential to enter the central nervous system.

Methods

and Findings: We conducted an analysis of CD8 T-cell function and severity of symptoms by self-report questionnaires in ME/CFS, Long COVID and healthy controls. We developed a CD8 T-cell functional assay, assessing CD8 T-cell dysfunction by intracellular cytokine staining (ICS) in a group of ME/CFS (n = 12) and Long COVID patients (n = 8), comparing to healthy controls (HC) with similar age and sex (n = 10). Magnet-enriched fresh CD8 T-cells in both patient groups had a significantly diminished capacity to produce both cytokines, IFNγ or TNFα, after PMA stimulation when compared to HC. The symptom severity questionnaire showed similar symptom profiles for the two disorders. Fortuitously, through a retrospective case series, we were able to examine the ICS and questionnaire data of 4 ME/CFS and 4 Long COVID patients in conjunction with their treatment (3-15 months). In parallel with the treatment pursued electively by participants in this retrospective case series, there was an increase in CD8 T-cell IFNγ and TNFα production and a decrease in overall self-reported symptom severity score by 54%. No serious treatment-associated side effects or laboratory anomalies were noted in these patients.

Conclusions

Here, in this small study, we present two observations that appear potentially fundamental to the pathogenesis and treatment of Long COVID and ME/CFS. The first is that both disorders appear to be characterized by dysfunctional CD8 T-cells with severe deficiencies in their abilities to produce IFNγ and TNFα. The second is that in a small retrospective Long COVID and ME/CFS case series, this immune dysfunction and patient health improved in parallel with treatment with an immunomodulatory, antioxidant pharmacological treatment with anticipated anti-pathogen activity. This work provides evidence of the potential utility of a biomarker, CD8 T-cell dysfunction, and suggests the potential for benefit from a new nebulized antioxidant/anti-pathogen treatment. These immune biomarker data may help build capacity for improved diagnosis and tracking of treatment outcomes during clinical trials for both Long COVID and ME/CFS while providing clues to new treatment avenues that suggest potential efficacy for both conditions.

In vitro B cell experiments explore the role of CD24, CD38, and energy metabolism in ME/CFS

Introduction

Disturbances of energy metabolism contribute to the clinical manifestations of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Previously, we found that B cells from ME/CFS patients have an increased expression of CD24, a modulator of many cellular functions including those of cell stress. The relative ability of B cells from ME/CFS patients and healthy controls (HC) to respond to rapid changes in energy demand was compared.

Methods

CD24, the ectonucleotidases CD39 and CD73, the NAD-degrading enzyme CD38, and mitochondrial mass (MM) were measured following cross-linking of the B cell receptor and costimulation with either T-cell-dependent or Toll-like-receptor-9-dependent agonists. The levels of metabolites consumed/produced were measured using 1H-NMR spectroscopy and analyzed in relation to cell growth and immunophenotype.

Results

Proliferating B cells from patients with ME/CFS showed a lower mitochondrial mass and a significantly increased usage of essential amino acids compared with those from HC, with a significantly delayed loss of CD24 and an increased expression of CD38 following stimulation.

Discussion

The immunophenotype results suggested the triggering of a stress response in ME/CFS B cells associated with the increased usage of additional substrates to maintain necessary ATP levels. Disturbances in energy metabolism in ME/CFS B cells were thus confirmed in a dynamic in vitro model, providing the basis for further mechanistic investigations.

Plasma acylcarnitine in elderly Taiwanese: as biomarkers of possible sarcopenia and sarcopenia

BACKGROUND

Sarcopenia is defined as the disease of muscle loss and dysfunction. The prevalence of sarcopenia is strongly age-dependent. It could bring about disability, hospitalization, and mortality. The purpose of this study was to identify plasma metabolites associated with possible sarcopenia and muscle function to improve disease monitoring and understand the mechanism of muscle strength and function decline.

METHODS

The participants were a group of healthy older adult who live in retirement homes in Asia (Taiwan) and can manage their daily lives without assistance. The participants were enrolled and divided into four groups: control (Con, n = 57); low physical function (LPF, n = 104); sarcopenia (S, n = 63); and severe sarcopenia (SS, n = 65) according to Asian countries that used Asian Working Group for Sarcopenia (AWGS) criteria. The plasma metabolites were used and the results were calculated as the difference between the control and other groups.

RESULTS

Clinical parameters, age, gender, body mass index (BMI), hand grip strength (HGS), gait speed (GS), blood urea nitrogen (BUN), hemoglobin, and hematocrit were significantly different between the control and LPF groups. Metabolite patterns of LPF, S, and SS were explored in our study. Plasma kynurenine (KYN) and acylcarnitines (C0, C4, C6, and C18:1-OH) were identified with higher concentrations in older Taiwanese adults with possible sarcopenia and S compared to the Con group. After multivariable adjustment, the data indicate that age, BMI, and butyrylcarnitine (C4) are more important factors to identify individuals with low physical function and sarcopenia.

CONCLUSION

This metabolomic study raises the importance of acylcarnitines on muscle mass and function. It suggests that age, BMI, BUN, KYN, and C4/Cr can be important evaluation markers for LPF (AUC: 0.766), S (AUC: 0.787), and SS (AUC: 0.919).

Solvation Plays a Key Role in Antioxidant-Mediated Attenuation of Elevated Creatinine Level: An In Vitro Spectroscopic Investigation

An elevated level of creatinine (CRN) is a mark of kidney ailment, and prolonged retention of such condition could lead to renal failure, associated with severe ischemia. Antioxidants are clinically known to excrete CRN from the body through urine, thereby reducing its level in blood. The molecular mechanism of such an exclusion process is still illusive. As the excretion channel is urine, solvation of the solute is expected to play a pivotal role. Here, we report a detailed time-domain and frequency-domain terahertz (THz) spectroscopic investigation to understand the solvation of CRN in the presence of two model antioxidants, mostly used to treat elevated CRN level: N-Acetyl-l-cysteine (NAC) and ascorbic acid (ASC). FTIR spectroscopy in the mid-infrared region and UV absorption spectroscopy measurements coupled with quantum chemical calculations [at the B3LYP/6-311G++(d,p) level] reveal that both NAC and ASC form HBonded complexes with CRN and rapidly undergo a barrier-less proton transfer process to form creatinium ions. THz measurements provide explicit evidence of the formation of highly solvated complexes compared with bare CRN, which eventually enables its excretion through urine. These observations could provide a foundation for designing more beneficial drugs to resolve kidney diseases..

Increased gut permeability and bacterial translocation are associated with fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome: implications for disease-related biomarker discovery

Background

There is growing evidence of the significance of gastrointestinal complaints in the impairment of the intestinal mucosal barrier function and inflammation in fibromyalgia (FM) and in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). However, data on intestinal permeability and gut barrier dysfunction in FM and ME/CFS are still limited with conflicting results. This study aimed to assess circulating biomarkers potentially related to intestinal barrier dysfunction and bacterial translocation and their association with self-reported symptoms in these conditions.

Methods

A pilot multicenter, cross-sectional cohort study with consecutive enrolment of 22 patients with FM, 30 with ME/CFS and 26 matched healthy controls. Plasma levels of anti-beta-lactoglobulin antibodies (IgG anti-β-LGB), zonulin-1 (ZO-1), lipopolysaccharides (LPS), soluble CD14 (sCD14) and interleukin-1-beta (IL-1β) were assayed using ELISA. Demographic and clinical characteristics of the participants were recorded using validated self-reported outcome measures. The diagnostic accuracy of each biomarker was assessed using the receiver operating characteristic (ROC) curve analysis.

Results

FM patients had significantly higher levels of anti-β-LGB, ZO-1, LPS, and sCD14 than healthy controls (all P < 0.0001). In ME/CFS patients, levels of anti-β-LGB, ZO-1, LPS, and sCD14 were significantly higher than controls, but lower than in FM (all P < 0.01), while there was no significant difference in IL-1β level. In the FM and ME/CFS cohorts, both anti-β-LGB and ZO-1 correlated significantly with LPS and sCD14 (P < 0.001 for both). In the FM group, both anti-β-LGB and ZO-1 were correlated significantly with physical and mental health components on the SF-36 scale (P < 0.05); whereas IL-1β negatively correlated with the COMPASS-31 score (P < 0.05). In the ME/CFS cohort, ZO-1 was positively correlated with the COMPASS-31 score (P < 0.05). The ROC curve analysis indicated a strong ability of anti-β-LGB, ZO-1, LPS and sCD14 to predictively distinguish between FM and ME/CFS from healthy controls (P < 0.0001).

Conclusion

Biomarkers of intestinal barrier function and inflammation were associated with autonomic dysfunction assessed by COMPASS-31 scores in FM and ME/CFS respectively. Anti-β-LGB antibodies, ZO-1, LPS, and sCD14 may be putative predictors of intestinal barrier dysfunction in these cohorts. Further studies are needed to assess whether these findings are causal and can therefore be applied in clinical practice.

Dose-effect of long-snake-like moxibustion for chronic fatigue syndrome: a randomized controlled trial

BACKGROUND

The dose-effect relationship of Long-snake-like moxibustion for chronic fatigue syndrome (CFS) remains poorly understood. In order to address this gap, we designed this trial to assess the association between different treatment duration of Long-snake-like moxibustion and its effects on CFS based on the combination measurements of the subjective patient-reported scales with objective medical infrared imaging technology─Thermal Texture Maps (TTM).

METHODS

From December 2020 to January 2022, 60 female CFS patients were recruited and equally allocated to two groups: Group A, receiving 60-min Long-snake-like moxibustion per treatment, and Group B, receiving 30-min Long-snake-like moxibustion per treatment. The treatment was administered 3 times per week for a total of 4 weeks. The primary outcome was defined as the improvement of symptoms measured by the Fatigue scale-14 (FS-14), and secondary outcomes were designated as the improvement in Symptoms Scale of Spleen-Kidney Yang Deficiency, Self-rating depression scale, and Self-rating anxiety scale. TTM scanning was employed twice for CFS patients (before and after 4-week treatment) and once for Healthy control subjects (HCs).

RESULTS

At week 4, the scores of FS-14 and Symptoms Scale of Spleen-Kidney Yang Deficiency in Group A were significantly lower than those in Group B (physical fatigue: 5.00 vs. 6.00, with 95%CI - 2.00 to 0.00, p = 0.003; FS-14 total score: 8.00 vs. 9.00, with 95%CI - 3.00 to 0.00, p = 0.012; total score of Symptoms Scale of Spleen-Kidney Yang Deficiency: 9.80 vs. 13.07, with 95%CI - 5.78 to - 0.76, P = 0.012). All thermal radiation values of the two groups increased, and statistical differences in ΔTs between Group A and HCs were not obtained. More significant correlations between symptoms improvements and ΔT changes were observed in Group A, and its ΔT changes in Upper Jiao, Shenque (CV8), Zhongwan (CV12), Danzhong (CV17), Zhiyang (GV9), Dazhui (GV14), upper arm, thoracic segments, lumbar segments, renal region, popliteal fossa strongly correlated with the improvement of Spleen-Kidney Yang Deficiency symptoms.

CONCLUSIONS

In the same course of treatment, the positive dose-effect relationship was found between the treatment duration of Long-snake-like moxibustion and CFS effect assessment. 60-min Long-snake-like moxibustion per treatment were associated with optimal clinical response and TTM improvement.

TRIAL REGISTRATION

Chinese Clinical Trail Registry (No. ChiCTR2000041000, date of registration: 16 December 2020), http://www.chictr.org.cn/showproj.aspx?proj=62488.

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature

Some patients remain unwell for months after "recovering" from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars. In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

Carnitine derivatives beyond fatigue: an update

PURPOSE OF REVIEW

Carnitine is an essential micronutrient that transfer long-chain fatty acids from the cytoplasm into the mitochondrial matrix for the β-oxidation. Carnitine is also needed for the mitochondrial efflux of acyl groups in the cases wherein substrate oxidation exceeds energy demands.

RECENT FINDINGS

Carnitine deficiency can affect the oxidation of free fatty acids in the mitochondria resulting in the aggregation of lipids in the cytoplasm instead of entering the citric acid cycle. The aggregation leads a lack of energy, acetyl coenzyme A accumulation in the mitochondria and cytotoxic production.

SUMMARY

Carnitine and its derivatives show great clinical therapeutic effect without significant side effects.

Altered Fatty Acid Oxidation in Lymphocyte Populations of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disabling multisystem illness in which individuals are plagued with fatigue, inflammatory symptoms, cognitive dysfunction, and the hallmark symptom, post-exertional malaise. While the cause of this disease remains unknown, there is evidence of a potential infectious component that, along with patient symptoms and common onsets of the disease, implicates immune system dysfunction. To further our understanding of the state of ME/CFS lymphocytes, we characterized the role of fatty acids in isolated Natural Killer cells, CD4+ T cells, and CD8+ T cells in circulation and after overnight stimulation, through implicit perturbations to fatty acid oxidation. We examined samples obtained from at least 8 and as many as 20 subjects for immune cell fatty acid characterization in a variety of experiments and found that all three isolated cell types increased their utilization of lipids and levels of pertinent proteins involved in this metabolic pathway in ME/CFS samples, particularly during higher energy demands and activation. In T cells, we characterized the cell populations contributing to these metabolic shifts, which included CD4+ memory cells, CD4+ effector cells, CD8+ naïve cells, and CD8+ memory cells. We also discovered that patients with ME/CFS and healthy control samples had significant correlations between measurements of CD4+ T cell fatty acid metabolism and demographic data. These findings provide support for metabolic dysfunction in ME/CFS immune cells. We further hypothesize about the consequences that these altered fuel dependencies may have on T and NK cell effector function, which may shed light on the illness's mechanism of action.

Ginsenoside Rg1 can reverse fatigue behavior in CFS rats by regulating EGFR and affecting Taurine and Mannose 6-phosphate metabolism

Background: Chronic fatigue syndrome (CFS) is characterized by significant and persistent fatigue. Ginseng is a traditional anti-fatigue Chinese medicine with a long history in Asia, as demonstrated by clinical and experimental studies. Ginsenoside Rg1 is mainly derived from ginseng, and its anti-fatigue metabolic mechanism has not been thoroughly explored. Methods: We performed non-targeted metabolomics of rat serum using LC-MS and multivariate data analysis to identify potential biomarkers and metabolic pathways. In addition, we implemented network pharmacological analysis to reveal the potential target of ginsenoside Rg1 in CFS rats. The expression levels of target proteins were measured by PCR and Western blotting. Results: Metabolomics analysis confirmed metabolic disorders in the serum of CFS rats. Ginsenoside Rg1 can regulate metabolic pathways to reverse metabolic biases in CFS rats. We found a total of 34 biomarkers, including key markers Taurine and Mannose 6-phosphate. AKT1, VEGFA and EGFR were identified as anti-fatigue targets of ginsenoside Rg1 using network pharmacological analysis. Finally, biological analysis showed that ginsenoside Rg1 was able to down-regulate the expression of EGFR. Conclusion: Our results suggest ginsenoside Rg1 has an anti-fatigue effect, impacting the metabolism of Taurine and Mannose 6-phosphate through EGFR regulation. This demonstrates ginsenoside Rg1 is a promising alternative treatment for patients presenting with chronic fatigue syndrome.

Serum metabolomic abnormalities in survivors of non-severe COVID-19

Metabolic reprogramming is a distinctive characteristic of SARS-CoV-2 infection, which refers to metabolic changes in hosts triggered by viruses for their survival and spread. It is current urgent to understand the metabolic health status of COVID-19 survivors and its association with long-term health consequences of infection, especially for the predominant non-severe patients. Herein, we show systemic metabolic signatures of survivors of non-severe COVID-19 from Wuhan, China at six months after discharge using metabolomics approaches. The serum amino acids, organic acids, purine, fatty acids and lipid metabolism were still abnormal in the survivors, but the kynurenine pathway and the level of itaconic acid have returned to normal. These metabolic abnormalities are associated with liver injury, mental health, energy production, and inflammatory responses. Our findings identify and highlight the metabolic abnormalities in survivors of non-severe COVID-19, which provide information on biomarkers and therapeutic targets of infection and cues for post-hospital care and intervention strategies centered on metabolism reprogramming.

Pre-illness data reveals differences in multiple metabolites and metabolic pathways in those who do and do not recover from infectious mononucleosis

Metabolic pathways related to energy production, amino acids, nucleotides, nitrogen, lipids, and neurotransmitters in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may contribute to the pathophysiology of ME/CFS. 4501 Northwestern University college students were enrolled in a prospective, longitudinal study. We collected data before illness, during infectious mononucleosis (IM), and at a 6 month follow-up for those who recovered (N = 18) versus those who went on to develop ME/CFS 6 months later (N = 18). Examining pre-illness blood samples, we found significant detectable metabolite differences between participants fated to develop severe ME/CFS following IM versus recovered controls. We identified glutathione metabolism, nucleotide metabolism, and the TCA cycle (among others) as potentially dysregulated pathways. The pathways that differed between cases and controls are essential for proliferating cells, particularly during a pro-inflammatory immune response. Performing a series of binary logistic regressions using a leave-one-out cross-validation (LOOCV), our models correctly classified the severe ME/CFS group and recovered controls with an accuracy of 97.2%, sensitivity of 94.4%, and specificity of 100.0%. These changes are consistent with the elevations in pro-inflammatory cytokines that we have reported for patients fated to develop severe ME/CFS 6 months after IM.

Neurological & psychological aspects of Barth syndrome: Clinical manifestations and potential pathogenic mechanisms

Barth syndrome is a rare X-linked multisystem mitochondrial disease that is caused by variants in the tafazzin gene leading to deficient and abnormal cardiolipin. Previous research has focused on the cardiomyopathy and neutropenia in individuals with Barth syndrome, yet just as common are the least explored neurological aspects of Barth syndrome. This review focuses on the major neuropsychological and neurophysiological phenotypes that affect the quality of life of individuals with Barth syndrome, including difficulties in sensory perception and feeding, fatigue, and cognitive and psychological challenges. We propose selected pathogenetic mechanisms underlying these phenotypes and draw parallels to other relevant disorders. Finally, avenues for future research are also suggested.

Pathophysiology of skeletal muscle disturbances in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Chronic Fatigue Syndrome or Myalgic Encephaloymelitis (ME/CFS) is a frequent debilitating disease with an enigmatic etiology. The finding of autoantibodies against ß2-adrenergic receptors (ß2AdR) prompted us to hypothesize that ß2AdR dysfunction is of critical importance in the pathophysiology of ME/CFS. Our hypothesis published previously considers ME/CFS as a disease caused by a dysfunctional autonomic nervous system (ANS) system: sympathetic overactivity in the presence of vascular dysregulation by ß2AdR dysfunction causes predominance of vasoconstrictor influences in brain and skeletal muscles, which in the latter is opposed by the metabolically stimulated release of endogenous vasodilators (functional sympatholysis). An enigmatic bioenergetic disturbance in skeletal muscle strongly contributes to this release. Excessive generation of these vasodilators with algesic properties and spillover into the systemic circulation could explain hypovolemia, suppression of renin (paradoxon) and the enigmatic symptoms. In this hypothesis paper the mechanisms underlying the energetic disturbance in muscles will be explained and merged with the first hypothesis. The key information is that ß2AdR also stimulates the Na+/K+-ATPase in skeletal muscles. Appropriate muscular perfusion as well as function of the Na+/K+-ATPase determine muscle fatigability. We presume that dysfunction of the ß2AdR also leads to an insufficient stimulation of the Na+/K+-ATPase causing sodium overload which reverses the transport direction of the sodium-calcium exchanger (NCX) to import calcium instead of exporting it as is also known from the ischemia-reperfusion paradigm. The ensuing calcium overload affects the mitochondria, cytoplasmatic metabolism and the endothelium which further worsens the energetic situation (vicious circle) to explain postexertional malaise, exercise intolerance and chronification. Reduced Na+/K+-ATPase activity is not the only cause for cellular sodium loading. In poor energetic situations increased proton production raises intracellular sodium via sodium-proton-exchanger subtype-1 (NHE1), the most important proton-extruder in skeletal muscle. Finally, sodium overload is due to diminished sodium outward transport and enhanced cellular sodium loading. As soon as this disturbance would have occurred in a severe manner the threshold for re-induction would be strongly lowered, mainly due to an upregulated NHE1, so that it could repeat at low levels of exercise, even by activities of everyday life, re-inducing mitochondrial, metabolic and vascular dysfunction to perpetuate the disease.

Insights into Metabolite Diagnostic Biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a persistent and unexplained pathological state characterized by exertional and severely debilitating fatigue, with/without infectious or neuropsychiatric symptoms, and with a minimum duration of 6 consecutive months. Its pathogenesis is not fully understood. There are no firmly established diagnostic biomarkers or treatment, due to incomplete understanding of the etiology of ME/CFS and diagnostic uncertainty. Establishing a biomarker for the objective diagnosis is urgently needed to treat a lot of patients. Recently, research on ME/CFS using metabolome analysis methods has been increasing. Here, we overview recent findings concerning the metabolic features in patients with ME/CFS and the animal models which contribute to the development of diagnostic biomarkers for ME/CFS and its treatment. In addition, we discuss future perspectives of studies on ME/CFS.

Ross River Virus Immune Evasion Strategies and the Relevance to Post-viral Fatigue, and Myalgic Encephalomyelitis Onset

Ross River virus (RRV) is an endemic Australian arbovirus, and member of the Alphavirus family that also includes Chikungunya virus (CHIK). RRV is responsible for the highest prevalence of human disease cases associated with mosquito-borne transmission in Australia, and has long been a leading suspect in cases of post-viral fatigue syndromes, with extrapolation of this link to Myalgic Encephalomyelitis (ME). Research into RRV pathogenesis has revealed a number of immune evasion strategies, impressive for a virus with a genome size of 12 kb (plus strand RNA), which resonate with insights into viral pathogenesis broadly. Drawing from observations on RRV immune evasion, mechanisms of relevance to long term idiopathic fatigue are featured as a perspective on infection and eventual ME symptoms, which include considerations of; (1) selective pro-inflammatory gene suppression post antibody-dependent enhancement (ADE) of RRV infection, (2) Evidence from other virus families of immune disruption and evasion post-ADE, and (3) how virally-driven immune evasion may impact on mitochondrial function via target of rapamycin (TOR) complexes. In light of these RRV measures to counter the host immune - inflammatory responses, links to recent discoveries explaining cellular, immune and metabolomic markers of ME will be explored and discussed, with the implications for long-COVID post SARS-CoV-2 also considered. Compelling issues on the connections between virally-induced alterations in cytokine expression, for example, will be of particular interest in light of energy pathways, and how these perturbations manifest clinically.

Patterns of Sequelae in Women with a History of Localized Breast Cancer: Results from the French VICAN Survey

Breast cancer (BC) remains complex for women both physically and psychologically. The objectives of this study were to (1) assess the evolution of the main sequelae and treatment two and five years after diagnosis in women with early-stage breast cancer, (2) explore patterns of sequelae associated with given sociodemographic, clinical, and lifestyle factors. The current analysis was based on 654 localized BC patients enrolled in the French nationwide longitudinal survey "vie après cancer" VICAN (January-June 2010). Information about study participants was collected at enrollment, two and five years after diagnosis. Changes over time of the main sequelae were analyzed and latent class analysis was performed to identify patterns of sequelae related to BC five years after diagnosis. The mean age (±SD) of study participants at inclusion was 49.7 (±10.5) years old. Six main classes of sequelae were identified two years and five years post-diagnosis (functional, pain, esthetic, fatigue, psychological, and gynecological). A significant decrease was observed for fatigue (p = 0.03) and an increase in cognitive sequelae was reported (p = 0.03). Two latent classes were identified-functional and esthetic patterns. Substantial sequelae remain up to five years after BC diagnosis. Changes in patient care pathways are needed to identify BC patients at a high risk.

In-Depth Analysis of the Plasma Proteome in ME/CFS Exposes Disrupted Ephrin-Eph and Immune System Signaling

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling disease with worldwide prevalence and limited therapies exclusively aimed at treating symptoms. To gain insights into the molecular disruptions in ME/CFS, we utilized an aptamer-based technology that quantified 4790 unique human proteins, allowing us to obtain the largest proteomics dataset yet available for this disease, detecting highly abundant proteins as well as rare proteins over a nine-log dynamic range. We report a pilot study of 20 ME/CFS patients and 20 controls, all females. Significant differences in the levels of 19 proteins between cohorts implicate pathways related to the extracellular matrix, the immune system and cell-cell communication. Outputs of pathway and cluster analyses robustly highlight the ephrin pathway, which is involved in cell-cell signaling and regulation of an expansive variety of biological processes, including axon guidance, angiogenesis, epithelial cell migration, and immune response. Receiver Operating Characteristic (ROC) curve analyses distinguish the plasma proteomes of ME/CFS patients from controls with a high degree of accuracy (Area Under the Curve (AUC) > 0.85), and even higher when using protein ratios (AUC up to 0.95), that include some protein pairs with established biological relevance. Our results illustrate the promise of plasma proteomics for diagnosing and deciphering the molecular basis of ME/CFS.

Exercise modifies glutamate and other metabolic biomarkers in cerebrospinal fluid from Gulf War Illness and Myalgic encephalomyelitis / Chronic Fatigue Syndrome

Myalgic encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) and Gulf War Illness (GWI) share many symptoms of fatigue, pain, and cognitive dysfunction that are not relieved by rest. Patterns of serum metabolites in ME/CFS and GWI are different from control groups and suggest potential dysfunction of energy and lipid metabolism. The metabolomics of cerebrospinal fluid was contrasted between ME/CFS, GWI and sedentary controls in 2 sets of subjects who had lumbar punctures after either (a) rest or (b) submaximal exercise stress tests. Postexercise GWI and control subjects were subdivided according to acquired transient postexertional postural tachycardia. Banked cerebrospinal fluid specimens were assayed using Biocrates AbsoluteIDQ® p180 kits for quantitative targeted metabolomics studies of amino acids, amines, acylcarnitines, sphingolipids, lysophospholipids, alkyl and ether phosphocholines. Glutamate was significantly higher in the subgroup of postexercise GWI subjects who did not develop postural tachycardia after exercise compared to nonexercise and other postexercise groups. The only difference between nonexercise groups was higher lysoPC a C28:0 in GWI than ME/CFS suggesting this biochemical or phospholipase activities may have potential as a biomarker to distinguish between the 2 diseases. Exercise effects were suggested by elevation of short chain acylcarnitine C5-OH (C3-DC-M) in postexercise controls compared to nonexercise ME/CFS. Limitations include small subgroup sample sizes and absence of postexercise ME/CFS specimens. Mechanisms of glutamate neuroexcitotoxicity may contribute to neuropathology and “neuroinflammation” in the GWI subset who did not develop postural tachycardia after exercise. Dysfunctional lipid metabolism may distinguish the predominantly female ME/CFS group from predominantly male GWI subjects.

Metabolic signatures of muscle mass loss in an elderly Taiwanese population

To identify the association between metabolites and muscle mass in 305 elderly Taiwanese subjects, we conducted a multivariate analysis of 153 plasma samples. Based on appendicular skeletal muscle mass index (ASMI) quartiles, female and male participants were divided into four groups. Quartile 4 (Men: 5.67±0.35, Women: 4.70±0.32 Kg/m²) and quartile 1 (Men: 7.60±0.29, Women: 6.56±0.53 Kg/m²) represented low muscle mass and control groups, respectively. After multivariable adjustment, except for physical function, we found that blood urea nitrogen, creatinine, and age were associated with ASMI in men. However, only triglyceride level was related to ASMI in women. The multiple logistic regression models were used to analyze in each baseline characteristic and metabolite concentration. After the adjustment, we identify amino acid-related metabolites and show that glutamate levels in women and alpha-aminoadipate, Dopa, and citrulline/ornithine levels in men are gender-specific metabolic signatures of muscle mass loss.

Myalgic encephalomyelitis/chronic fatigue syndrome patients exhibit altered T cell metabolism and cytokine associations

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disease with no known cause or mechanism. There is an increasing appreciation for the role of immune and metabolic dysfunction in the disease. ME/CFS has historically presented in outbreaks, often has a flu-like onset, and results in inflammatory symptoms. Patients suffer from severe fatigue and postexertional malaise. There is little known about the metabolism of specific immune cells in patients with ME/CFS. To investigate immune metabolism in ME/CFS, we isolated CD4+ and CD8+ T cells from 53 patients with ME/CFS and 45 healthy controls. We analyzed glycolysis and mitochondrial respiration in resting and activated T cells, along with markers related to cellular metabolism and plasma cytokines. We found that ME/CFS CD8+ T cells had reduced mitochondrial membrane potential compared with those from healthy controls. Both CD4+ and CD8+ T cells from patients with ME/CFS had reduced glycolysis at rest, whereas CD8+ T cells also had reduced glycolysis following activation. Patients with ME/CFS had significant correlations between measures of T cell metabolism and plasma cytokine abundance that differed from correlations seen in healthy control subjects. Our data indicate that patients have impaired T cell metabolism consistent with ongoing immune alterations in ME/CFS that may illuminate the mechanism behind this disease.

Exercise alters brain activation in Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Gulf War Illness affects 25-30% of American veterans deployed to the 1990-91 Persian Gulf War and is characterized by cognitive post-exertional malaise following physical effort. Gulf War Illness remains controversial since cognitive post-exertional malaise is also present in the more common Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. An objective dissociation between neural substrates for cognitive post-exertional malaise in Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome would represent a biological basis for diagnostically distinguishing these two illnesses. Here, we used functional magnetic resonance imaging to measure neural activity in healthy controls and patients with Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome during an N-back working memory task both before and after exercise. Whole brain activation during working memory (2-Back > 0-Back) was equal between groups prior to exercise. Exercise had no effect on neural activity in healthy controls yet caused deactivation within dorsal midbrain and cerebellar vermis in Gulf War Illness relative to Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients. Further, exercise caused increased activation among Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients within the dorsal midbrain, left operculo-insular cortex (Rolandic operculum) and right middle insula. These regions-of-interest underlie threat assessment, pain, interoception, negative emotion and vigilant attention. As they only emerge post-exercise, these regional differences likely represent neural substrates of cognitive post-exertional malaise useful for developing distinct diagnostic criteria for Gulf War Illness and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Cell-Based Blood Biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a devastating illness whose biomedical basis is now beginning to be elucidated. We reported previously that, after recovery from frozen storage, lymphocytes (peripheral blood mononuclear cells, PBMCs) from ME/CFS patients die faster in culture medium than those from healthy controls. We also found that lymphoblastoid cell lines (lymphoblasts) derived from these PBMCs exhibit multiple abnormalities in mitochondrial respiratory function and signalling activity by the cellular stress-sensing kinase Target Of Rapamycin Complex 1 (TORC1). These differences were correlated with disease severity, as measured by the Richardson and Lidbury weighted standing test. The clarity of the differences between these cells derived from ME/CFS patient blood and those from healthy controls suggested that they may provide useful biomarkers for ME/CFS. Here, we report a preliminary investigation into that possibility using a variety of analytical classification tools, including linear discriminant analysis, logistic regression and receiver operating characteristic (ROC) curve analysis. We found that results from three different tests—lymphocyte death rate, mitochondrial respiratory function and TORC1 activity—could each individually serve as a biomarker with better than 90% sensitivity but only modest specificity vís a vís healthy controls. However, in combination, they provided a cell-based biomarker with sensitivity and specificity approaching 100% in our sample. This level of sensitivity and specificity was almost equalled by a suggested protocol in which the frozen lymphocyte death rate was used as a highly sensitive test to triage positive samples to the more time consuming and expensive tests measuring lymphoblast respiratory function and TORC1 activity. This protocol provides a promising biomarker that could assist in more rapid and accurate diagnosis of ME/CFS.

Using the NIH symptom science model to understand fatigue and mitochondrial bioenergetics

The symptom of fatigue is prevalent among patients with chronic diseases and conditions such as congestive heart failure and cancer. It has a significant debilitating impact on patients' physical health, quality of life, and well-being. Early detection and appropriate assessment of fatigue is essential for diagnosing, treating, and monitoring disease progression. However, it is often challenging to manage the symptom of fatigue without first investigating the underlying biological mechanisms. In this narrative review, we conceptualize the symptom of fatigue and its relationship with mitochondrial bioenergetics using the National Institute of Health Symptom Science Model (NIH-SSM). In particular, we discuss mental and physical measures to assess fatigue, the importance of adenosine triphosphate (ATP) in cellular and organ functions, and how impaired ATP production contributes to fatigue. Specific methods to measure ATP are described. Recommendations are provided concerning how to integrate biological mechanisms with the symptom of fatigue for future research and clinical practice to help alleviate symptoms and improve patients' quality of life.

Efficacy of Korean red ginseng (Panax ginseng) for middle-aged and moderate level of chronic fatigue patients: A randomized, double-blind, placebo-controlled trial

OBJECTIVES

Chronic fatigue (CF) is unexplained fatigue lasting more than 6 months. Korean red ginseng (KRG) is known to have higher anti-fatigue substance than white ginseng. However, its efficacy and safety for CF is unknown. The purpose of this study was to investigate the effect of KRG on CF by various measurements and objective indicators.

DESIGN

A randomized, double-blind, clinical trial was conducted on 50 patients with CF.

INTERVENTION

Participants were allocated to KRG or placebo group (1:1 ratio) and visited hospital every 2 weeks during taking 3 g KRG or placebo for 6 weeks and followed up 4 weeks after the treatment.

MAIN OUTCOME MEASURES

The primary outcome measurement was fatigue VAS. Secondary outcome measurements included FSS, CFSQ, SRI, scales of various fields (Depression: BDI; Sleep: ISI; Quality of life: EQ-5D 5 L), biochemical test (Antioxidants: d-ROMs, TBARS, BAP, and SOD; Cortisol concentration: salivary cortisol), blinding assessment, and adverse events.

RESULTS

The fatigue VAS declined significantly in each group, but there were no significant differences between the groups. The 2 groups also had no significant differences in the secondary outcome measurements and there were no adverse events. Sub-group analysis indicated that patients with initial fatigue VAS below 80 mm and older than 50 years had significantly greater reductions in the fatigue VAS if they used KRG rather than placebo.

CONCLUSIONS

By our study, KRG did not show absolute anti-fatigue effect but provided the objective evidence of fatigue-related measurement and the therapeutic potential for middle-aged individuals with moderate fatigue.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown aetiology that is recognized by the World Health Organization (WHO) and the United States Center for Disease Control and Prevention (US CDC) as a disorder of the brain. The disease predominantly affects adults, with a peak age of onset of between 20 and 45 years with a female to male ratio of 3:1. Although the clinical features of the disease have been well established within diagnostic criteria, the diagnosis of ME/CFS is still of exclusion, meaning that other medical conditions must be ruled out. The pathophysiological mechanisms are unclear but the neuro-immuno-endocrinological pattern of CFS patients gleaned from various studies indicates that these three pillars may be the key point to understand the complexity of the disease. At the moment, there are no specific pharmacological therapies to treat the disease, but several studies' aims and therapeutic approaches have been described in order to benefit patients' prognosis, symptomatology relief, and the recovery of pre-existing function. This review presents a pathophysiological approach to understanding the essential concepts of ME/CFS, with an emphasis on the population, clinical, and genetic concepts associated with ME/CFS.

Pathological Mechanisms Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

The underlying molecular basis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is not well understood. Characterized by chronic, unexplained fatigue, a disabling payback following exertion ("post-exertional malaise"), and variably presenting multi-system symptoms, ME/CFS is a complex disease, which demands a concerted biomedical investigation from disparate fields of expertise. ME/CFS research and patient treatment have been challenged by the lack of diagnostic biomarkers and finding these is a prominent direction of current work. Despite these challenges, modern research demonstrates a tangible biomedical basis for the disorder across many body systems. This evidence is mostly comprised of disturbances to immunological and inflammatory pathways, autonomic and neurological dysfunction, abnormalities in muscle and mitochondrial function, shifts in metabolism, and gut physiology or gut microbiota disturbances. It is possible that these threads are together entangled as parts of an underlying molecular pathology reflecting a far-reaching homeostatic shift. Due to the variability of non-overlapping symptom presentation or precipitating events, such as infection or other bodily stresses, the initiation of body-wide pathological cascades with similar outcomes stemming from different causes may be implicated in the condition. Patient stratification to account for this heterogeneity is therefore one important consideration during exploration of potential diagnostic developments.

Rethinking ME/CFS Diagnostic Reference Intervals via Machine Learning, and the Utility of Activin B for Defining Symptom Severity

Biomarker discovery applied to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a disabling disease of inconclusive aetiology, has identified several cytokines to potentially fulfil a role as a quantitative blood/serum marker for laboratory diagnosis, with activin B a recent addition. We explored further the potential of serum activin B as a ME/CFS biomarker, alone and in combination with a range of routine test results obtained from pathology laboratories. Previous pilot study results showed that activin B was significantly elevated for the ME/CFS participants compared to healthy (control) participants. All the participants were recruited via CFS Discovery and assessed via the Canadian/International Consensus Criteria. A significant difference for serum activin B was also detected for ME/CFS and control cohorts recruited for this study, but median levels were significantly lower for the ME/CFS cohort. Random Forest (RF) modelling identified five routine pathology blood test markers that collectively predicted ME/CFS at ≥62% when compared via weighted standing time (WST) severity classes. A closer analysis revealed that the inclusion of activin B to the panel of pathology markers improved the prediction of mild to moderate ME/CFS cases. Applying correct WST class prediction from RFA modelling, new reference intervals were calculated for activin B and associated pathology markers, where 24-h urinary creatinine clearance, serum urea and serum activin B showed the best potential as diagnostic markers. While the serum activin B results remained statistically significant for the new participant cohorts, activin B was found to also have utility in enhancing the prediction of symptom severity, as represented by WST class.

Evidence of Clinical Pathology Abnormalities in People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) from an Analytic Cross-Sectional Study

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease presenting with extreme fatigue, post-exertional malaise, and other symptoms. In the absence of a diagnostic biomarker, ME/CFS is diagnosed clinically, although laboratory tests are routinely used to exclude alternative diagnoses. In this analytical cross-sectional study, we aimed to explore potential haematological and biochemical markers for ME/CFS, and disease severity. We reviewed laboratory test results from 272 people with ME/CFS and 136 healthy controls participating in the UK ME/CFS Biobank (UKMEB). After corrections for multiple comparisons, most results were within the normal range, but people with severe ME/CFS presented with lower median values (p < 0.001) of serum creatine kinase (CK; median = 54 U/L), compared to healthy controls (HCs; median = 101.5 U/L) and non-severe ME/CFS (median = 84 U/L). The differences in CK concentrations persisted after adjusting for sex, age, body mass index, muscle mass, disease duration, and activity levels (odds ratio (OR) for being a severe case = 0.05 (95% confidence interval (CI) = 0.02-0.15) compared to controls, and OR = 0.16 (95% CI = 0.07-0.40), compared to mild cases). This is the first report that serum CK concentrations are markedly reduced in severe ME/CFS, and these results suggest that serum CK merits further investigation as a biomarker for severe ME/CFS.

Small Molecule Oligopeptides Isolated from Walnut (Juglans regia L.) and Their Anti-Fatigue Effects in Mice

Walnut (Juglans regia L.) is unique for its extensive biological activities and pharmaceutical properties. There are few studies on walnut oligopeptides (WOPs), which are small molecule peptides extracted from walnuts. This study aimed to evaluate the anti-fatigue effects of WOPs on ICR mice and explore the possible underlying mechanism. Mice were randomly divided into four experimental sets and each set of mice were then randomly divided into four groups. The vehicle group was administered distilled water, and the three WOP intervention groups were orally administered WOP solution at a dose of 110, 220, and 440 mg/kg of body weight, respectively. After 30 days of WOP intervention, the anti-fatigue activity of WOPs were evaluated using the weight-loaded swimming test and by measuring the change of biochemical parameters, glycogen storage and energy metabolism enzymes, anti-oxidative capacity and mitochondrial function. It was observed that WOPs could significantly prolong the swimming time, decrease the accumulation of lactate dehydrogenase (LDH), creatine kinase (CK), blood urea nitrogen (BUN) and blood lactic acid (BLA), and increased the glycogen storage of liver and gastrocnemius muscle. WOPs also markedly inhibited fatigue induced oxidative stress by increasing the activity of superoxide dismutase (SOD), glutathione peroxidase (GPX) and decreasing the content malondialdehyde (MDA). Notably, WOPs improved the activity of pyruvate kinase (PK), succinate dehydrogenase (SDH), Na+-K+-ATPase, and enhanced the mRNA expression of mitochondrial biogenesis factors and mitochondrial DNA content in skeletal muscles of mice. These results suggest that WOPs have beneficial anti-fatigue effects, which may be attributed to their positive effects on increasing glycogen storage, improving energy metabolism, inhibiting oxidative stress, enhancing mitochondrial function in skeletal muscle, and ameliorating the cell damage and the muscular injury.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-Metabolic Disease or Disturbed Homeostasis due to Focal Inflammation in the Hypothalamus?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disease characterized by debilitating fatigue, lasting for at least 6 months, with associated malaise, headaches, sleep disturbance, and cognitive impairment, which severely impacts quality of life. A significant percentage of ME/CFS patients remain undiagnosed, mainly due to the complexity of the disease and the lack of reliable objective biomarkers. ME/CFS patients display decreased metabolism and the severity of symptoms appears to be directly correlated to the degree of metabolic reduction that may be unique to each individual patient. However, the precise pathogenesis is still unknown, preventing the development of effective treatments. The ME/CFS phenotype has been associated with abnormalities in energy metabolism, which are apparently due to mitochondrial dysfunction in the absence of mitochondrial diseases, resulting in reduced oxidative metabolism. Such mitochondria may be further contributing to the ME/CFS symptomatology by extracellular secretion of mitochondrial DNA, which could act as an innate pathogen and create an autoinflammatory state in the hypothalamus. We propose that stimulation of hypothalamic mast cells by environmental, neuroimmune, pathogenic and stress triggers activates microglia, leading to focal inflammation in the brain and disturbed homeostasis. This process could be targeted for the development of novel effective treatments.

Insights into myalgic encephalomyelitis/chronic fatigue syndrome phenotypes through comprehensive metabolomics

The pathogenesis of ME/CFS, a disease characterized by fatigue, cognitive dysfunction, sleep disturbances, orthostatic intolerance, fever, irritable bowel syndrome (IBS), and lymphadenopathy, is poorly understood. We report biomarker discovery and topological analysis of plasma metabolomic, fecal bacterial metagenomic, and clinical data from 50 ME/CFS patients and 50 healthy controls. We confirm reports of altered plasma levels of choline, carnitine and complex lipid metabolites and demonstrate that patients with ME/CFS and IBS have increased plasma levels of ceramide. Integration of fecal metagenomic and plasma metabolomic data resulted in a stronger predictive model of ME/CFS (cross-validated AUC = 0.836) than either metagenomic (cross-validated AUC = 0.745) or metabolomic (cross-validated AUC = 0.820) analysis alone. Our findings may provide insights into the pathogenesis of ME/CFS and its subtypes and suggest pathways for the development of diagnostic and therapeutic strategies.

Infection Elicited Autoimmunity and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: An Explanatory Model

Myalgic encephalomyelitis (ME) often also called chronic fatigue syndrome (ME/CFS) is a common, debilitating, disease of unknown origin. Although a subject of controversy and a considerable scientific literature, we think that a solid understanding of ME/CFS pathogenesis is emerging. In this study, we compiled recent findings and placed them in the context of the clinical picture and natural history of the disease. A pattern emerged, giving rise to an explanatory model. ME/CFS often starts after or during an infection. A logical explanation is that the infection initiates an autoreactive process, which affects several functions, including brain and energy metabolism. According to our model for ME/CFS pathogenesis, patients with a genetic predisposition and dysbiosis experience a gradual development of B cell clones prone to autoreactivity. Under normal circumstances these B cell offsprings would have led to tolerance. Subsequent exogenous microbial exposition (triggering) can lead to comorbidities such as fibromyalgia, thyroid disorder, and orthostatic hypotension. A decisive infectious trigger may then lead to immunization against autoantigens involved in aerobic energy production and/or hormone receptors and ion channel proteins, producing postexertional malaise and ME/CFS, affecting both muscle and brain. In principle, cloning and sequencing of immunoglobulin variable domains could reveal the evolution of pathogenic clones. Although evidence consistent with the model accumulated in recent years, there are several missing links in it. Hopefully, the hypothesis generates testable propositions that can augment the understanding of the pathogenesis of ME/CFS.

Myalgic encephalomyelitis, chronic fatigue syndrome: An infectious disease

The etiology of myalgic encephalomyelitis also known as chronic fatigue syndrome or ME/CFS has not been established. Controversies exist over whether it is an organic disease or a psychological disorder and even the existence of ME/CFS as a disease entity is sometimes denied. Suggested causal hypotheses have included psychosomatic disorders, infectious agents, immune dysfunctions, autoimmunity, metabolic disturbances, toxins and inherited genetic factors. Clinical, immunological and epidemiological evidence supports the hypothesis that: ME/CFS is an infectious disease; the causal pathogen persists in patients; the pathogen can be transmitted by casual contact; host factors determine susceptibility to the illness; and there is a population of healthy carriers, who may be able to shed the pathogen. ME/CFS is endemic globally as sporadic cases and occasional cluster outbreaks (epidemics). Cluster outbreaks imply an infectious agent. An abrupt flu-like onset resembling an infectious illness occurs in outbreak patients and many sporadic patients. Immune responses in sporadic patients resemble immune responses in other infectious diseases. Contagion is shown by finding secondary cases in outbreaks, and suggested by a higher prevalence of ME/CFS in sporadic patients' genetically unrelated close contacts (spouses/partners) than the community. Abortive cases, sub-clinical cases, and carrier state individuals were found in outbreaks. The chronic phase of ME/CFS does not appear to be particularly infective. Some healthy patient-contacts show immune responses similar to patients' immune responses, suggesting exposure to the same antigen (a pathogen). The chronicity of symptoms and of immune system changes and the occurrence of secondary cases suggest persistence of a causal pathogen. Risk factors which predispose to developing ME/CFS are: a close family member with ME/CFS; inherited genetic factors; female gender; age; rest/activity; previous exposure to stress or toxins; various infectious diseases preceding the onset of ME/CFS; and occupational exposure of health care professionals. The hypothesis implies that ME/CFS patients should not donate blood or tissue and usual precautions should be taken when handling patients' blood and tissue. No known pathogen has been shown to cause ME/CFS. Confirmation of the hypothesis requires identification of a causal pathogen. Research should focus on a search for unknown and known pathogens. Finding a causal pathogen could assist with diagnosis; help find a biomarker; enable the development of anti-microbial treatments; suggest preventive measures; explain pathophysiological findings; and reassure patients about the validity of their symptoms.

Bottom-up proteomics suggests an association between differential expression of mitochondrial proteins and chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a debilitating and complex disorder characterized by unexplained fatigue not improved by rest. An area of investigation is the likely connection of CFS with defective mitochondrial function. In a previous work, we investigated the proteomic salivary profile in a couple of monozygotic twins discordant for CFS. Following this work, we analyzed mitochondrial proteins in the same couple of twins. Nano-liquid chromatography electrospray ionization mass spectrometry (nano-LC-MS) was used to study the mitochondria extracted from platelets of the twins. Subsequently, we selected three proteins that were validated using western blot analysis in a big cohort of subjects (n=45 CFS; n=45 healthy), using whole saliva (WS). The selected proteins were as follows: aconitate hydratase (ACON), ATP synthase subunit beta (ATPB) and malate dehydrogenase (MDHM). Results for ATPB and ACON confirmed their upregulation in CFS. However, the MDHM alteration was not confirmed. Thereafter, seeing the great variability of clinical features of CFS patients, we decided to analyze the expression of our proteins after splitting patients according to clinical parameters. For each marker, the values were actually higher in the group of patients who had clinical features similar to the ill twin. In conclusion, these results suggest that our potential markers could be one of the criteria to be taken into account for helping in diagnosis. Furthermore, the identification of biomarkers present in particular subgroups of CFS patients may help in shedding light upon the complex entity of CFS. Moreover, it could help in developing tailored treatments.

Hyperhomocysteinemia associated skeletal muscle weakness involves mitochondrial dysfunction and epigenetic modifications

HHcy has been implicated in elderly frailty, but the underlying mechanisms are poorly understood. Using C57 and CBS+/- mice and C2C12 cell line, we investigated mechanisms behind HHcy induced skeletal muscle weakness and fatigability. Possible alterations in metabolic capacity (levels of LDH, CS, MM-CK and COX-IV), in structural proteins (levels of dystrophin) and in mitochondrial function (ATP production) were examined. An exercise regimen was employed to reverse HHcy induced changes. CBS+/- mice exhibited more fatigability, and generated less contraction force. No significant changes in muscle morphology were observed. However, there is a corresponding reduction in large muscle fiber number in CBS+/- mice. Excess fatigability was not due to changes in key enzymes involved in metabolism, but was due to reduced ATP levels. A marginal reduction in dystrophin levels along with a decrease in mitochondrial transcription factor A (mtTFA) were observed. There was also an increase in the mir-31, and mir-494 quantities that were implicated in dystrophin and mtTFA regulation respectively. The molecular changes elevated during HHcy, with the exception of dystrophin levels, were reversed after exercise. In addition, the amount of NRF-1, one of the transcriptional regulators of mtTFA, was significantly decreased. Furthermore, there was enhancement in mir-494 levels and a concomitant decline in mtTFA protein quantity in homocysteine treated cells. These changes in C2C12 cells were also accompanied by an increase in DNMT3a and DNMT3b proteins and global DNA methylation levels. Together, these results suggest that HHcy plays a causal role in enhanced fatigability through mitochondrial dysfunction which involves epigenetic changes.