Category: Biomarker

Altered muscle membrane potential and redox status differentiates two subgroups of patients with chronic fatigue syndrome

Abstract:

BACKGROUND: In myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), altered membrane excitability often occurs in exercising muscles demonstrating muscle dysfunction regardless of any psychiatric disorder. Increased oxidative stress is also present in many ME/CFS patients and could affect the membrane excitability of resting muscles.

METHODS: Seventy-two patients were examined at rest, during an incremental cycling exercise and during a 10-min post-exercise recovery period. All patients had at least four criteria leading to a diagnosis of ME/CFS. To explore muscle membrane excitability, M-waves were recorded during exercise (rectus femoris (RF) muscle) and at rest (flexor digitorum longus (FDL) muscle). Two plasma markers of oxidative stress (thiobarbituric acid reactive substance (TBARS) and oxidation-reduction potential (ORP)) were measured. Plasma potassium (K+) concentration was also measured at rest and at the end of exercise to explore K+ outflow.

RESULTS: Thirty-nine patients had marked M-wave alterations in both the RF and FDL muscles during and after exercise while the resting values of plasma TBARS and ORP were increased and exercise-induced K+ outflow was decreased. In contrast, 33 other patients with a diagnosis of ME/CFS had no M-wave alterations and had lower baseline levels of TBARS and ORP. M-wave changes were inversely proportional to TBARS and ORP levels.

CONCLUSIONS: Resting muscles of ME/CFS patients have altered muscle membrane excitability. However, our data reveal heterogeneity in some major biomarkers in ME/CFS patients. Measurement of ORP may help to improve the diagnosis of ME/CFS.

Trial registration Ethics Committee “Ouest II” of Angers (May 17, 2019) RCB ID: number 2019-A00611-56.

Source: Jammes Y, Adjriou N, Kipson N, Criado C, Charpin C, Rebaudet S, Stavris C, Guieu R, Fenouillet E, Retornaz F. Altered muscle membrane potential and redox status differentiates two subgroups of patients with chronic fatigue syndrome. J Transl Med. 2020 Apr 19;18(1):173. doi: 10.1186/s12967-020-02341-9. https://www.ncbi.nlm.nih.gov/pubmed/32306967

HERV-K and HERV-W transcriptional activity in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/MS) is an incapacitating chronic disease that dramatically compromise the life quality. The CFS/ME pathogenesis is multifactorial, and it is believed that immunological, metabolic and environmental factors play a role. It is well documented an increased activity of Human endogenous retroviruses (HERVs) from different families in autoimmune and neurological diseases, making these elements good candidates for biomarkers or even triggers for such diseases.

METHODS: Here the expression of Endogenous retroviruses K and W (HERV-K and HERV-W) was determined in blood from moderately and severely affected ME/CFS patients through real time PCR.

RESULTS: HERV-K was overexpressed only in moderately affected individuals but HERV-W showed no difference.

CONCLUSIONS: This is the first report about HERV-K differential expression in moderate ME/CFS. Although the relationship between HERVs and ME/CFS has yet to be proven, the observation of this phenomenon deserves further attention.

Source: Rodrigues LS, da Silva Nali LH, Leal COD, Sabino EC, Lacerda EM, Kingdon CC, Nacul L, Romano CM. HERV-K and HERV-W transcriptional activity in myalgic encephalomyelitis/chronic fatigue syndrome. Auto Immun Highlights. 2019 Nov 15;10(1):12. doi: 10.1186/s13317-019-0122-8. eCollection 2019 Dec. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065355/ (Full text)

A Machine Learning Approach to the Differentiation of Functional Magnetic Resonance Imaging Data of Chronic Fatigue Syndrome (CFS) From a Sedentary Control

Abstract:

Chronic Fatigue Syndrome (CFS) is a debilitating condition estimated to impact at least 1 million individuals in the United States, however there persists controversy about its existence. Machine learning algorithms have become a powerful methodology for evaluating multi-regional areas of fMRI activation that can classify disease phenotype from sedentary control. Uncovering objective biomarkers such as an fMRI pattern is important for lending credibility to diagnosis of CFS.

fMRI scans were evaluated for 69 patients (38 CFS and 31 Control) taken before (Day 1) and after (Day 2) a submaximal exercise test while undergoing the n-back memory paradigm. A predictive model was created by grouping fMRI voxels into the Automated Anatomical Labeling (AAL) atlas, splitting the data into a training and testing dataset, and feeding these inputs into a logistic regression to evaluate differences between CFS and control. Model results were cross-validated 10 times to ensure accuracy. Model results were able to differentiate CFS from sedentary controls at a 80% accuracy on Day 1 and 76% accuracy on Day 2 (Table 3).

Recursive features selection identified 29 ROI’s that significantly distinguished CFS from control on Day 1 and 28 ROI’s on Day 2 with 10 regions of overlap shared with Day 1 (Figure 3). These 10 shared regions included the putamen, inferior frontal gyrus, orbital (F3O), supramarginal gyrus (SMG), temporal pole; superior temporal gyrus (T1P) and caudate ROIs. This study was able to uncover a pattern of activated neurological regions that differentiated CFS from Control.

This pattern provides a first step toward developing fMRI as a diagnostic biomarker and suggests this methodology could be emulated for other disorders. We concluded that a logistic regression model performed on fMRI data significantly differentiated CFS from Control.

Source: Provenzano D, Washington SD, Baraniuk JN. A Machine Learning Approach to the Differentiation of Functional Magnetic Resonance Imaging Data of Chronic Fatigue Syndrome (CFS) From a Sedentary Control. Front Comput Neurosci. 2020 Jan 29;14:2. doi: 10.3389/fncom.2020.00002. eCollection 2020. https://www.ncbi.nlm.nih.gov/pubmed/32063839

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

Abstract:

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.

Source: Missailidis D, Sanislav O, Allan CY, Annesley SJ, Fisher PR. Cell-Based Blood Biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Int J Mol Sci. 2020 Feb 8;21(3). pii: E1142. doi: 10.3390/ijms21031142. https://www.ncbi.nlm.nih.gov/pubmed/32046336

A laboratory approach for characterizing chronic fatigue: what does metabolomics tell us?

Abstract:

INTRODUCTION: Manifestations of fatigue range from chronic fatigue up to a severe syndrome and myalgic encephalomyelitis. Fatigue grossly affects the functional status and quality of life of affected individuals, prompting the World Health Organization to recognize it as a chronic non-communicable condition.

OBJECTIVES: Here, we explore the potential of urinary metabolite information to complement clinical criteria of fatigue, providing an avenue towards an objective measure of fatigue in patients presenting with the full spectrum of fatigue levels.

METHODS: The experimental group consisted of 578 chronic fatigue female patients. The measurement design was composed of (1) existing clinical fatigue scales, (2) a hepatic detoxification challenge test, and (3) untargeted proton nuclear magnetic resonance (1H-NMR) procedure to generate metabolomics data. Data analysed via an in-house Matlab script that combines functions from a Statistics and a PLS Toolbox.

RESULTS: Multivariate analysis of the original 459 profiled 1H-NMR bins for the low (control) and high (patient) fatigue groups indicated complete separation following the detoxification experimental challenge. Important bins identified from the 1H-NMR spectra provided quantitative metabolite information on the detoxification challenge for the fatigue groups.

CONCLUSIONS: Untargeted 1H-NMR metabolomics proved its applicability as a global profiling tool to reveal the impact of toxicological interventions in chronic fatigue patients. No clear potential biomarker emerged from this study, but the quantitative profile of the phase II biotransformation products provide a practical visible effect directing to up-regulation of crucial phase II enzyme systems in the high fatigue group in response to a high xenobiotic-load.

Source: Erasmus E, Mason S, van Reenen M, Steffens FE, Vorster BC, Reinecke CJ. A laboratory approach for characterizing chronic fatigue: what does metabolomics tell us? Metabolomics. 2019 Nov 27;15(12):158. doi: 10.1007/s11306-019-1620-4. https://www.ncbi.nlm.nih.gov/pubmed/31776682

Identification of actin network proteins, talin-1 and filamin-A, in circulating extracellular vesicles as blood biomarkers for human myalgic encephalomyelitis/ chronic fatigue syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious, debilitating disorder with a wide spectrum of symptoms, including pain, depression, and neurocognitive deterioration. Over 17 million people around the world have ME/CFS, predominantly women with peak onset at 30-50 years. Given the wide spectrum of symptoms and unclear etiology, specific biomarkers for diagnosis and stratification of ME/CFS are lacking. Here we show that actin network proteins in circulating extracellular vesicles (EVs) offer specific non-invasive biomarkers for ME/CFS.

We found that circulating EVs were significantly increased in ME/CFS patients correlating to C-reactive protein, as well as biological antioxidant potential. Area under the receiver operating characteristic curve for circulating EVs was 0.80, allowing correct diagnosis in 90-94% of ME/CFS cases. From two independent proteomic analyses using circulating EVs from ME/CFS, healthy controls, idiopathic chronic fatigue, and depression, proteins identified from ME/CFS patients are involved in focal adhesion, actin skeletal regulation, PI3K-Akt signaling pathway, and Epstein-Barr virus infection. In particular, talin-1, filamin-A, and 14-3-3 family proteins were the most abundant proteins, representing highly specific ME/CFS biomarkers.

Our results identified circulating EV number and EV-specific proteins as novel biomarkers for diagnosing ME/CFS, providing important information on the pathogenic mechanisms of ME/CFS.

Copyright © 2019. Published by Elsevier Inc.

Source: Eguchi A, Fukuda S, Kuratsune H, Nojima J, Nakatomi Y, Watanabe Y, Feldstein AE. Identification of actin network proteins, talin-1 and filamin-A, in circulating extracellular vesicles as blood biomarkers for human myalgic encephalomyelitis/ chronic fatigue syndrome. Brain Behav Immun. 2019 Nov 20. pii: S0889-1591(19)30762-7. doi: 10.1016/j.bbi.2019.11.015. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31759091

Retinal nerve fiber layer thinning in chronic fatigue syndrome as a possible ocular biomarker of underlying glymphatic system dysfunction

In a recent article published in Medical Hypotheses, my colleague and I speculated that glymphatic dysfunction, causing toxic build up within the central nervous system, may be responsible for at least some cases of chronic fatigue syndrome (CFS) [1]. We further postulated that cerebrospinal fluid diversion such as lumboperitoneal shunting may be beneficial to this subgroup of patients by restoring glymphatic transport and waste removal from the brain. In this context, it would be helpful to have a predictive biomarker that can identify CFS patients who are good candidates for this specific treatment. For reasons discussed below, I believe that retinal nerve fiber layer (RNFL) thinning may be a sign of underlying glymphatic system dysfunction in neurodegenerative diseases that result from protein toxicity.

Read the rest of this article here.

A systematic review of cytokines in chronic fatigue syndrome/myalgic encephalomyelitis/systemic exertion intolerance disease (CFS/ME/SEID)

Abstract:

BACKGROUND: Cytokines in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis/Systemic Exertion Intolerance Disease (CFS/ME/SEID) patients compared with healthy controls have been extensively studied. However, the evidence regarding whether a baseline difference between CFS/ME/SEID patients and the normal population remains unclear. The aim of this study was to conduct a systematic review of the literature regarding cytokines in CFS/ME/SEID and whether there is a significant difference in cytokine levels between this patient group and the normal population.

METHODS: Pubmed, Scopus, Medline (EBSCOHost), and EMBASE databases were searched to source relevant studies for CFS/ME/SEID. The review included any studies examining cytokines in CFS/ME/SEID patients compared with healthy controls. Results of the literature search were summarised according to aspects of their study design and outcome measures, namely, cytokines. Quality assessment was also completed to summarise the level of evidence available.

RESULTS: A total of 16,702 publications were returned using our search terms. After screening of papers according to our inclusion and exclusion criteria, 15 studies were included in the review. All the included studies were observational case control studies. Ten of the studies identified measured serum cytokines in CFS/ME/SEID patients, and four measured cytokines in other physiological fluids of CFS/ME/SEID patients. The overall quality assessment revealed most papers included in this systematic review to be consistent.

CONCLUSIONS: Despite the availability of moderate quality studies, the findings of this review are inconclusive as to whether cytokines play any definitive role in CFS/ME/SEID, and consequently, they would not serve as reliable biomarkers. Therefore, in light of these results, it is recommended that further efforts toward a diagnostic test and treatment for CFS/ME/SEID continue to be developed in a range of research fields.

Source: Corbitt M, Eaton-Fitch N, Staines D, Cabanas H, Marshall-Gradisnik S. A systematic review of cytokines in chronic fatigue syndrome/myalgic encephalomyelitis/systemic exertion intolerance disease (CFS/ME/SEID). BMC Neurol. 2019 Aug 24;19(1):207. doi: 10.1186/s12883-019-1433-0. https://bmcneurol.biomedcentral.com/articles/10.1186/s12883-019-1433-0 (Full article)

Assessing cellular energy dysfunction in CFS/ME using a commercially available laboratory test

Abstract:

The mitochondrial energy score (MES) protocol, developed by the Myhill group, is marketed as a diagnostic test for chronic fatigue syndrome/Myalgic Encephalomyelitis (CFS/ME). This study assessed the reliability and reproducibility of the test, currently provided by private clinics, to assess its potential to be developed as an NHS accredited laboratory test.

We replicated the MES protocol using neutrophils and peripheral blood mononuclear cells (PBMCs) from CFS/ME patients (10) and healthy controls (13). The protocol was then repeated in PBMCs and neutrophils from healthy controls to investigate the effect of delayed sample processing time used by the Myhill group.

Experiments using the established protocol showed no differences between CFS/ME patients and healthy controls in any of the components of the MES (p ≥ 0.059). Delaying blood sample processing by 24 hours (well within the 72 hour time frame quoted by the Myhill group) significantly altered many of the parameters used to calculate the MES in both neutrophils and PBMCs. The MES test does not have the reliability and reproducibility required of a diagnostic test and therefore should not currently be offered as a diagnostic test for CFS/ME. The differences observed by the Myhill group may be down to differences in sample processing time between cohorts.

Source: Tomas C, Lodge TA, Potter M, Elson JL, Newton JL, Morten KJ. Assessing cellular energy dysfunction in CFS/ME using a commercially available laboratory test. Sci Rep. 2019 Aug 7;9(1):11464. doi: 10.1038/s41598-019-47966-z. https://www.ncbi.nlm.nih.gov/pubmed/31391529

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

Abstract:

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.

Source: Lidbury BA, Kita B, Richardson AM, Lewis DP, Privitera E, Hayward S, de Kretser D, Hedger M. Rethinking ME/CFS Diagnostic Reference Intervals via Machine Learning, and the Utility of Activin B for Defining Symptom Severity. Diagnostics (Basel). 2019 Jul 19;9(3). pii: E79. doi: 10.3390/diagnostics9030079. https://www.mdpi.com/2075-4418/9/3/79 (Full article)