Transient receptor potential melastatin 2 channels are overexpressed in myalgic encephalomyelitis/chronic fatigue syndrome patients

Abstract:

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is hallmarked by a significant reduction in natural killer (NK) cell cytotoxicity, a mechanism tightly regulated by calcium (Ca2+). Interestingly, interleukin-2 (IL-2) increases NK cell cytotoxicity. Transient receptor potential melastatin 2 (TRPM2) ion channels are fundamental for Ca2+ signalling in NK cells. This pilot investigation aimed to characterise TRPM2 and CD38 surface expression in vitro on NK cells in ME/CFS patients. This investigation furthermore examined the pharmaceutical effect of 8-bromoadenosine phosphoribose (8-Br-ADPR) and N6-Benzoyladenosine-3′,5′-cyclic monophosphate (N6-Bnz-cAMP) on TRPM2 and CD38 surface expression and NK cell cytotoxicity between ME/CFS and healthy control (HC) participants.

METHODS: Ten ME/CFS patients (43.45 ± 12.36) and 10 HCs (43 ± 12.27) were age and sex-matched. Isolated NK cells were labelled with fluorescent antibodies to determine baseline and drug-treated TRPM2 and CD38 surface expression on NK cell subsets. Following IL-2 stimulation, NK cell cytotoxicity was measured following 8-Br-ADPR and N6-Bnz-cAMP drug treatments by flow cytometry.

RESULTS: Baseline TRPM2 and CD38 surface expression was significantly higher on NK cell subsets in ME/CFS patients compared with HCs. Post IL-2 stimulation, TRPM2 and CD38 surface expression solely decreased on the CD56DimCD16+ subset. 8-Br-ADPR treatment significantly reduced TRPM2 surface expression on the CD56BrightCD16Dim/- subset within the ME/CFS group. Baseline cell cytotoxicity was significantly reduced in ME/CFS patients, however no changes were observed post drug treatment in either group.

CONCLUSION: Overexpression of TRPM2 on NK cells may function as a compensatory mechanism to alert a dysregulation in Ca2+ homeostasis to enhance NK cell function in ME/CFS, such as NK cell cytotoxicity. As no improvement in NK cell cytotoxicity was observed within the ME/CFS group, an impairment in the TRPM2 ion channel may be present in ME/CFS patients, resulting in alterations in [Ca2+]i mobilisation and influx, which is fundamental in driving NK cell cytotoxicity. Differential expression of TRPM2 between NK cell subtypes may provide evidence for their role in the pathomechanism involving NK cell cytotoxicity activity in ME/CFS.

Source: Balinas C, Cabanas H, Staines D, Marshall-Gradisnik S. Transient receptor potential melastatin 2 channels are overexpressed in myalgic encephalomyelitis/chronic fatigue syndrome patients. J Transl Med. 2019 Dec 3;17(1):401. doi: 10.1186/s12967-019-02155-4. https://www.ncbi.nlm.nih.gov/pubmed/31796045

Myalgic encephalomyelitis and chronic fatigue syndrome case definitions: effects of requiring a substantial reduction in functioning

Abstract:

BACKGROUND: Current case definitions for myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) require an individual to report a ‘substantial reduction’ in activity levels, when compared to premorbid functioning. However, little guidance is provided on how to measure these reductions, as well as what level of reduction should be deemed ‘substantial,’ leading to inconsistencies in how this criterion is applied across research settings.

PURPOSE: The current study examined the influence of substantial reduction criterion on case definitions.

METHOD: The current study analyzed an international convenience sample of 1002 individuals with ME or CFS, 53 healthy controls, and 260 controls with other chronic illnesses.

RESULTS: Findings indicated that the utility of the substantial reduction criterion varied by case definition, with more stringent case definitions not needing this criterion to identify cases.

CONCLUSION: These results suggest that the requirement of a substantial reduction in functioning may be redundant when case definitions specify that individuals must endorse a set of core symptoms at specified frequency and severity levels.

Source: Scartozzi S, Sunnquist M, Jason LA. Myalgic encephalomyelitis and chronic fatigue syndrome case definitions: effects of requiring a substantial reduction in functioning. Fatigue. 2019;7(2):59-68. doi: 10.1080/21641846.2019.1600825. Epub 2019 Apr 1. https://www.ncbi.nlm.nih.gov/pubmed/31788347

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

Parasympathetic activity is reduced during slow-wave sleep, but not resting wakefulness, in patients with chronic fatigue syndrome

Abstract:

STUDY OBJECTIVES: Physiological dearousal characterized by an increase in parasympathetic nervous system activity is important for good-quality sleep. Previous research shows that nocturnal parasympathetic activity (reflected by heart rate variability [HRV]) is diminished in individuals with chronic fatigue syndrome (CFS), suggesting hypervigilant sleep. This study investigated differences in nocturnal autonomic activity across sleep stages and explored the association of parasympathetic activity with sleep quality and self-reported physical and psychological wellbeing in individuals with CFS.

METHODS: Twenty-four patients with medically diagnosed CFS, and 24 matched healthy control individuals participated. Electroencephalography and HRV were recorded during sleep in participants’ homes using a minimally invasive ambulatory device. Questionnaires were used to measure self-reported wellbeing and sleep quality.

RESULTS: Sleep architecture in patients with CFS differed from that of control participants in slower sleep onset, more awakenings, and a larger proportion of time spent in slow-wave sleep (SWS). Linear mixed-model analyses controlling for age revealed that HRV reflecting parasympathetic activity (normalized high frequency power) was reduced in patients with CFS compared to control participants, particularly during deeper stages of sleep. Poorer self-reported wellbeing and sleep quality was associated with reduced parasympathetic signaling during deeper sleep, but not during wake before sleep, rapid eye movement sleep, or with the proportion of time spent in SWS.

CONCLUSIONS: Autonomic hypervigilance during the deeper, recuperative stages of sleep is associated with poor quality sleep and self-reported wellbeing. Causal links need to be confirmed but provide potential intervention opportunities for the core symptom of unrefreshing sleep in CFS.

© 2019 American Academy of Sleep Medicine.

Source: Fatt SJ, Beilharz JE, Joubert M, Wilson C, Lloyd AR, Vollmer-Conna U, Cvejic E. Parasympathetic activity is reduced during slow-wave sleep, but not resting wakefulness, in patients with chronic fatigue syndrome. J Clin Sleep Med. 2019 Nov 27. pii: jc-19-00271. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31771749

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

Low-dose naltrexone in the treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Background: Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is a common medical condition that limits physical and cognitive functions, with no known effective medical treatment.

Methods: We report on the safety and effectiveness data accumulated in clinical practice when treating ME/CFS with low-dose naltrexone (LDN, 3.0 – 4.5 mg/day). The medical records from 218 patients who received ar diagnosis of ME/CFS and LDN treatment during 2010–2014 were retrospectively analyzed.

Results: Outcome data were available in 92.2% of patients with an average follow-up time of 1.7 years. A positive treatment response to LDN was reported by 73.9% of the patients. Most patients experienced improved vigilance/alertness and improved physical and cognitive performance. Some patients reported less pain and fever, while 18.3% of patients did not report any treatment response to LDN. Mild adverse effects (insomnia, nausea) were common at the beginning of the treatment. Neither severe adverse effects nor long-term adverse symptoms were reported.

Conclusions: The high frequency of treatment response and good safety profile observed in this retrospective open label study could prompt prospective controlled studies to confirm the feasibility of LDN in alleviating ME/CFS symptoms.

Source: Olli Polo, Pia Pesonen & Essi Tuominen (2019) Low-dose naltrexone in the treatment of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), Fatigue: Biomedicine, Health & Behavior, DOI: 10.1080/21641846.2019.1692770 https://www.tandfonline.com/doi/full/10.1080/21641846.2019.1692770

A systematic review of natural killer cells profile and cytotoxic function in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: Compromised natural killer (NK) cell cytotoxic function is a well-documented and consistent feature of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Other outcomes evaluated in NK cells of ME/CFS patients, however, remain equivocal. The aim of this study was to conduct a systematic review of the literature regarding NK cell phenotype, receptor expression, cytokine production and cytotoxicity in ME/CFS patients and determine the appropriateness as a model for ME/CFS.

METHODS: Medline (EBSCOHost), Scopus, EMBASE and PubMed databases were systematically searched to source relevant papers published between 1994 and March 2018. This review included studies examining NK cells’ features in ME/CFS patients compared with HC following administration of specific inclusion and exclusion criteria. Secondary outcomes included genetic analysis in isolated NK cells or quality of life assessment. Quality assessment was completed using the Downs and Black checklist in addition to The Joanna Briggs Institute checklist.

RESULTS: Seventeen eligible publications were included in this review. All studies were observational case control studies. Of these, 11 investigated NK cell cytotoxicity, 14 investigated NK cell phenotype and receptor profiles, three examined NK cell cytokine production, six investigated NK cell lytic protein levels and four investigated NK cell degranulation. Impaired NK cell cytotoxicity remained the most consistent immunological report across all publications. Other outcomes investigated differed between studies.

CONCLUSION: A consistent finding among all papers included in this review was impaired NK cell cytotoxicity, suggesting that it is a reliable and appropriate cellular model for continued research in ME/CFS patients. Aberrations in NK cell lytic protein levels were also reported. Although additional research is recommended, current research provides a foundation for subsequent investigations. It is possible that NK cell abnormalities can be used to characterise a subset of ME/CFS due to the heterogeneity of both the illness itself and findings between studies investigating specific features of NK function.

Source: Eaton-Fitch N, du Preez S, Cabanas H, Staines D, Marshall-Gradisnik S. A systematic review of natural killer cells profile and cytotoxic function in myalgic encephalomyelitis/chronic fatigue syndrome. Syst Rev. 2019 Nov 14;8(1):279. doi: 10.1186/s13643-019-1202-6. https://www.ncbi.nlm.nih.gov/pubmed/31727160

The longitudinal effects of seated isometric yoga on blood biomarkers, autonomic functions, and psychological parameters of patients with chronic fatigue syndrome: a pilot study

Abstract:

BACKGROUND: In a previous randomized controlled trial, we found that practicing seated isometric yoga regularly for 2 months improved the fatigue of patients with chronic fatigue syndrome (CFS) who are resistant to conventional therapy. The aim of this pilot study was to investigate the possible mechanisms behind this finding by comparing blood biomarkers, autonomic nervous function, and psychological indices before versus after an intervention period of seated isometric yoga practice.

METHODS: Fifteen patients with CFS who did not show satisfactory improvements after at least 6 months of conventional therapy practiced seated isometric yoga (biweekly 20-min sessions with a yoga instructor and daily practice at home) for 2 months. The longitudinal effects of seated isometric yoga on fatigue, blood biomarkers, autonomic function, and psychological state were investigated by comparing the following parameters before and after the intervention period: Fatigue severity was assessed by the Chalder fatigue scale (FS) score. Levels of the blood biomarkers cortisol, DHEA-S, TNF-α, IL-6, prolactin, carnitine, TGF-β1, BDNF, MHPG, HVA, and α-MSH were measured. The autonomic nervous functions assessed were heart rate (HR) and HR variability. Psychological indices included the 20-item Toronto Alexithymia Scale (TAS-20) and the Hospital Anxiety and Depression Scale (HADS).

RESULTS: Practicing seated isometric yoga for 2 months resulted in significant reductions in the Chalder FS (P = 0.002) and HADS-depression (P = 0.02) scores. No significant changes were observed in any other parameter evaluated. The change in Chalder FS score was not correlated with the change in HADS-depression score. However, this change was positively correlated with changes in the serum TNF-α levels (P = 0.048), the high frequency component of HR variability (P = 0.042), and TAS-20 scores (P = 0.001).

CONCLUSIONS: Regular practice of seated isometric yoga for 2 months reduced the fatigue and depressive symptom scores of patients with CFS without affecting any other parameters we investigated. This study failed to identify the markers responsible for the longitudinal fatigue-relieving effect of seated isometric yoga. However, considering that the reduced fatigue was associated with decreased serum TNF-α level and TAS-20 scores, fatigue improvement might be related to reduced inflammation and improved alexithymia in these patients.

TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN CTR) UMIN000009646. Registered Dec 27, 2012.

© The Author(s). 2019.

Source: Oka, T., Tanahashi, T., Lkhagvasuren, B. et al. The longitudinal effects of seated isometric yoga on blood biomarkers, autonomic functions, and psychological parameters of patients with chronic fatigue syndrome: a pilot study. BioPsychoSocial Med 13, 28 (2019) doi:10.1186/s13030-019-0168-x https://bpsmedicine.biomedcentral.com/articles/10.1186/s13030-019-0168-x#citeas (Full article)

Developing and pretesting a new patient reported outcome measure for paediatric Chronic Fatigue Syndrome/ Myalgic Encephalopathy (CFS/ME): cognitive interviews with children.

Abstract:

BACKGROUND: There is a lack of patient derived, child specific outcome measures to capture what health outcomes are important to children with Chronic Fatigue Syndrome/ Myalgic Encephalopathy (CFS/ME). We developed a new Patient Reported Outcome Measure (PROM) for paediatric CFS/ME through qualitative research with children. This study aimed to pre-test the new measure through cognitive interviews with children with CFS/ME.

METHODS: Cognitive interviews were undertaken in children’s homes or over Skype. The Three-Step Test-Interview (TSTI) method was used to assess the quality of the draft PROM with children with CFS/ME to identify problems with initial content and design and test modifications over subsequent interview rounds. Children were purposively sampled from a single specialist paediatric CFS/ME service in England.

RESULTS: Twenty-four children and their parents took part. They felt the new measure captured issues relevant to their condition and preferred it to the generic measures they completed in clinical assessment. Changes were made to item content and phrasing, timeframe and response options and tested through three rounds of interviews.

CONCLUSIONS: Cognitive interviews identified problems with the draft PROM, enabling us to make changes and then confirm acceptability in children aged 11-18. Further cognitive interviews are required with children 8-10 years old to examine the acceptability and content validity and provide evidence for age related cut offs of the new PROM to meet FDA standards. This study demonstrates the content validity of the new measure as relevant and acceptable for children with CFS/ME. The next stage is to undertake a psychometric evaluation to support the reduction of items, confirm the structure of the PROM and provide evidence of the data quality, reliability and validity.

Source: Parslow RM, Shaw A, Haywood KL, Crawley E. Developing and pretesting a new patient reported outcome measure for paediatric Chronic Fatigue Syndrome/ Myalgic Encephalopathy (CFS/ME): cognitive interviews with children. J Patient Rep Outcomes. 2019 Nov 9;3(1):67. doi: 10.1186/s41687-019-0156-8. https://www.ncbi.nlm.nih.gov/pubmed/31707635

Naltrexone Restores Impaired Transient Receptor Potential Melastatin 3 Ion Channel Function in Natural Killer Cells From Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a seriously long-term and debilitating illness of unknown cause hallmarked by chronic pain and fatigue, memory and concentration impairment, and inflammation. ME/CFS hypothesis involves impaired Transient receptor potential melastatin 3 (TRPM3) ion channel function, affecting calcium signaling and Natural killer (NK) cell functions.

Currently, substances called opioids, agonists of mu (μ)-opioid receptors (μOR), are the strongest painkillers clinically available for people suffering from strong or long-lasting pain characteristic of ME/CFS. μOR have been reported to specifically inhibit TRPM3 and to be expressed in immune cells where they play an immunomodulatory and immunosuppressive role. Naltrexone hydrochloride (NTX) acts as an antagonist to the μOR thus negating the inhibitory function of this opioid receptor on TRPM3.

Therefore, understanding the mechanism of action for NTX in regulating and modulating TRPM3 channel function in NK cells will provide important information for the development of effective therapeutic interventions for ME/CFS. Whole-cell patch-clamp technique was used to measure TRPM3 activity in Interleukin-2 (IL-2) stimulated and NTX-treated NK cells for 24 h on eight ME/CFS patients and 8 age- and sex-matched healthy controls, after modulation with a TRPM3-agonist, pregnenolone sulfate (PregS), NTX and a TRPM3-antagonist, ononetin. We confirmed impaired TRPM3 function in ME/CFS patients through electrophysiological investigations in IL-2 stimulated NK cells after modulation with PregS and ononetin.

Importantly, TRPM3 channel activity was restored in IL-2 stimulated NK cells isolated from ME/CFS patients after incubation for 24 h with NTX. Moreover, we demonstrated that NTX does not act as an agonist by directly coupling on the TRPM3 ion channel gating. The opioid antagonist NTX has the potential to negate the inhibitory function of opioid receptors on TRPM3 in NK cells from ME/CFS patients, resulting in calcium signals remodeling, which will in turn affect cell functions, supporting the hypothesis that NTX may have potential for use as a treatment for ME/CFS. Our results demonstrate, for the first time, and based on novel patch clamp electrophysiology, potential pharmaco-therapeutic interventions in ME/CFS.

Source: Cabanas H, Muraki K, Staines D and Marshall-Gradisnik S (2019) Naltrexone Restores Impaired Transient Receptor Potential Melastatin 3 Ion Channel Function in Natural Killer Cells From Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Front. Immunol. 10:2545. doi: 10.3389/fimmu.2019.02545 https://www.frontiersin.org/articles/10.3389/fimmu.2019.02545/full (Full article)