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Research Digest 30/10/20

Welcome to the 58th Emerge Australia Research Digest, where you will find summaries of some of the latest research and information about ME/CFS, with links to the complete articles.

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Characterization of Post–exertional Malaise in Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Authors: Stussman B, Williams A, Snow J, Gavin A, Scott R, Nath A, Walitt B (National Institutes of Health, US)
Publication: Frontiers in Neurology

Post–exertional malaise (PEM) is a key feature of ME/CFS, though it is still under-explored. Measurement of PEM has been controversial since patients have historically been excluded from the process of developing definitions. These authors sought to add to the understanding of PEM by gathering ME/CFS patients’ perspective on PEM. 

43 ME/CFS patients were divided into nine focus groups with four to seven people in each, and were asked about their experiences with PEM. Five of the groups were asked about PEM following cardiopulmonary exercise testing (CPET). Discussion was conducted over the telephone.

Patients experienced many symptoms during PEM but there were three core symptoms: exhaustion, cognitive difficulties and neuromuscular complaints. Eight themes were identified from the focus group discussions including PEM triggers, the wide symptom range of PEM, variability in PEM onset and the necessity of complete rest to ease PEM symptoms. The participants also reported that PEM following CPET was more immediate and of longer duration than PEM in daily life.

The authors conclude that PEM varies greatly between individuals and leads to a diminished quality of life. The figure below summarises the participants’ reported experience of PEM.

Autonomic Phenotypes in Chronic Fatigue Syndrome (CFS) are Associated with Illness Severity: A Cluster Analysis

Authors: Słomko J, Estévez-López F, Kujawski S, Zawadka-Kunikowska M, Tafil-Klawe M, Klawe JJ, Morten KJ,  Szrajda J, Murovska M, Newton JL, Zalewski P (Ludwik Rydygier Collegium Medicum, Poland)
Publication: Journal of Clinical Medicine

Dysregulation of systems which respond to stress, such as the hypothalamic-pituitary-adrenal axis, autonomic nervous system and immune system, are thought to be involved in ME/CFS. This study aimed to define and categorise the characteristics of autonomic subgroups for ME/CFS patients. The authors hypothesised that fatigue severity would vary according to autonomic phenotypes. 

A total of 131 ME/CFS patients (Fukuda criteria) participated in the study. Participants completed questionnaires related to sleep, fatigue and autonomic symptoms. Autonomic parameters were measured at rest using a Task Force Monitor and arterial stiffness using an Arteriograph.

Exploratory factor analysis yielded four principal factors: fatigue, subjective and objective autonomic dysfunction, and arterial stiffness. Cluster analysis grouped these factors into four autonomic profiles:

sympathetic with dysautonomia (34%)
sympathetic (5%)
parasympathetic (21%)
balanced (40%)
Patients in the sympathetic with dysautonomia subgroup were found to have more severe disease, higher subjective autonomic symptoms, higher sympathetic over-modulation and lower quality of life than those in the other subgroups. By contrast, patients in the the balanced subgroup had the highest level of quality of life, were the youngest, had a lower level of fatigue than either the sympathetic with dysautonomia or parasympathetic subgroups, and the lowest value of arterial stiffness.

The authors conclude that autonomic phenotypes in ME/CFS patients are strongly associated with disease severity and can help better understand the role of autonomic dysfunction in ME/CFS. They recommend that both subjective and objective measures of autonomic function be incorporated into the ME/CFS diagnostic process.
Review of the Quality Control Checks Performed by Current Genome-Wide and Targeted-Genome Association Studies on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
Authors: Grabowska AD, Lacerda EM, Nacul L, Sepúlveda N (London School of Hygiene & Tropical Medicine, UK)
Publication: Frontiers in Pediatrics

Four genome-wide association studies (GWAS) and two targeted-genome association studies (TGAS) have been conducted in the past decade with the purpose of identifying genetic factors associated with ME/CFS. These papers have yielded conflicting evidence, from no association through to moderate associations in some papers. These authors argue that assessment of the quality control (QC) checks performed in GWAS and TGAS is essential to ascertain the quality of the respective genetic data in these studies. This paper outlined the recommended QC checks for GWAS and TGAS, and then reviewed which were performed in the ME/CFS studies identified.

The authors found that only one of the six studies included all four recommended QC checks, and recommended that the data from another of the six studies be reanalysed to examine its validity due to the insufficient QC checks. The remaining studies included partial QC checks. The authors noted that study data was not open access, preventing them from undertaking further QC checks.

The authors also noted that genetic data on ME/CFS suffers from the lack of an objective biomarker for disease diagnosis, which is likely to introduce a possible misclassification of the true disease status of the recruited patients. They recommend the use of more advanced statistical methodology which incorporates such misclassification into the data analysis. 

The authors conclude that studies of ME/CFS should set data and methodological standards as high as those followed by the 1000 Human Genome Project and the UK10K project. Data sharing should also be a general practice to provide the researcher community the opportunity to perform additional checks or alternative analyses of the same data. Further, a stronger collaboration between the ME/CFS research community and statistical geneticists is recommended to promote better statistical analyses, improve data interpretations and, ultimately, a better assessment of the genetic component in ME/CFS.
Australian ME/CFS Research Centre Launched!

We are so thrilled to announce that we have partnered with Open Medicine Foundation (OMF) to launch the fifth OMF international research centre right here in Australia.

This new partnership means that we can now directly fund absolutely vital research to help more than 250,000 Australians living with ME/CFS.

The centre has been established by Open Medicine Foundation Australia, a new foundation set up to support biomedical research into ME/CFS in Australia.

The foundation has been created through a partnership between Emerge Australia and OMF. Any donations for research made to Emerge Australia will be directly passed to OMF Australia and will be used to support the new OMF centre headed by our very own Dr Chris Armstrong, a leading researcher into ME/CFS, and his team.

You can read more details about this wonderful initiative on our website here:

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