Brain function characteristics of chronic fatigue syndrome: A task fMRI study

Abstract:

The mechanism underlying neurological dysfunction in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is yet to be established. This study investigated the temporal complexity of blood oxygenation level dependent (BOLD) changes in response to the Stroop task in CFS patients. 43 CFS patients (47.4 ± 11.8 yrs) and 26 normal controls (NCs, 43.4 ± 13.9 yrs) were included in this study. Their mental component summary (MCS) and physical component summary (PCS) from the 36-item Short Form Health Survey (SF-36) questionnaire were recorded. Their Stroop colour-word task performance was measured by accuracy and response time (RT). The BOLD changes associated with the Stroop task were evaluated using a 2-level general linear model approach. The temporal complexity of the BOLD responses, a measure of information capacity and thus adaptability to a challenging environment, in each activated region was measured by sample entropy (SampEn).

The CFS patients showed significantly longer RTs than the NCs (P < 0.05) but no significant difference in accuracy. One sample t-tests for the two groups (Family wise error adjusted PFWE < 0.05) showed more BOLD activation regions in the CFS, although a two sample group comparison did not show significant difference. BOLD SampEns in ten regions were significantly lower (FDR-q < 0.05) in CFS patients. BOLD SampEns in 15 regions were significantly associated with PCS (FDR-q < 0.05) and in 9 regions were associated with MCS (FDR-q < 0.05) across all subjects. SampEn of the BOLD signal in the medioventral occipital cortex could explain 40% and 31% of the variance in the SF-36 PCS and MCS scores, and those in the precentral gyrus could explain an additional 16% and 7% across all subjects.

This is the first study to investigate BOLD signal SampEn in response to tasks in CFS. The results suggest the brain responds differently to a cognitive challenge in patients with CFS, with recruitment of wider regions to compensate for lower information capacity.

Source: Shan ZY, Finegan K, Bhuta S, Ireland T, Staines DR, Marshall-Gradisnik SM, Barnden LR. Brain function characteristics of chronic fatigue syndrome: A task fMRI study. Neuroimage Clin. 2018 Apr 25;19:279-286. doi: 10.1016/j.nicl.2018.04.025. eCollection 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051500/ (Full study)

High-fidelity discrete modeling of the HPA axis: a study of regulatory plasticity in biology

Abstract:

BACKGROUND: The hypothalamic-pituitary-adrenal (HPA) axis is a central regulator of stress response and its dysfunction has been associated with a broad range of complex illnesses including Gulf War Illness (GWI) and Chronic Fatigue Syndrome (CFS). Though classical mathematical approaches have been used to model HPA function in isolation, its broad regulatory interactions with immune and central nervous function are such that the biological fidelity of simulations is undermined by the limited availability of reliable parameter estimates.

METHOD: Here we introduce and apply a generalized discrete formalism to recover multiple stable regulatory programs of the HPA axis using little more than connectivity between physiological components. This simple discrete model captures cyclic attractors such as the circadian rhythm by applying generic constraints to a minimal parameter set; this is distinct from Ordinary Differential Equation (ODE) models, which require broad and precise parameter sets. Parameter tuning is accomplished by decomposition of the overall regulatory network into isolated sub-networks that support cyclic attractors. Network behavior is simulated using a novel asynchronous updating scheme that enforces priority with memory within and between physiological compartments.

RESULTS: Consistent with much more complex conventional models of the HPA axis, this parsimonious framework supports two cyclic attractors, governed by higher and lower levels of cortisol respectively. Importantly, results suggest that stress may remodel the stability landscape of this system, favoring migration from one stable circadian cycle to the other. Access to each regime is dependent on HPA axis tone, captured here by the tunable parameters of the multi-valued logic. Likewise, an idealized glucocorticoid receptor blocker alters the regulatory topology such that maintenance of persistently low cortisol levels is rendered unstable, favoring a return to normal circadian oscillation in both cortisol and glucocorticoid receptor expression.

CONCLUSION: These results emphasize the significance of regulatory connectivity alone and how regulatory plasticity may be explored using simple discrete logic and minimal data compared to conventional methods.

Source: Sedghamiz H, Morris M, Craddock TJA, Whitley D, Broderick G. High-fidelity discrete modeling of the HPA axis: a study of regulatory plasticity in biology. BMC Syst Biol. 2018 Jul 17;12(1):76. doi: 10.1186/s12918-018-0599-1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050677/ (Full article)

Personalised relaxation practice to improve sleep and functioning in patients with chronic fatigue syndrome and depression: study protocol for a randomised controlled trial

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) and major depressive disorder (MDD) are both debilitating but heterogeneous conditions sharing core features of fatigue, unrefreshing sleep, and impaired functioning. The aetiology of these conditions is not fully understood, and ‘best-practice’ treatments are only moderately effective in relieving symptoms. Unrecognised individual differences in the response to such treatments are likely to underlie poor treatment outcomes.

METHODS/DESIGN: We are undertaking a two-group, parallel, randomised controlled trial (RCT) comparing the effects of a personalised relaxation intervention on sleep quality, daytime symptoms, and functioning in patients with CFS (n = 64) and MDD (n = 64). Following identification of the method that best enhances autonomic responding (such as heart rate variability), participants randomised to the active intervention will practise their recommended method nightly for 4 weeks. All participants will keep a sleep diary and monitor symptoms during the trial period, and they will complete two face-to-face assessments, one at baseline and one at 4 weeks, and a further online assessment to evaluate lasting effects of the intervention at 2 months. Assessments include self-report measures of sleep, wellbeing, and function and monitoring of autonomic responses at rest, in response to the relaxation method and during nocturnal sleep. Treatment outcomes will be analysed using linear mixed modelling.

DISCUSSION: This is the first RCT examining the effects of a personalised relaxation intervention, pre-tested to maximise the autonomic relaxation response, in patients with unrefreshing sleep and fatigue attributed to CFS or MDD. Detailed monitoring of sleep quality and symptoms will enable sensitive detection of improvements in the core symptoms of these debilitating conditions. In addition, repeated monitoring of autonomic functioning can elucidate mechanisms underlying potential benefits. The findings have translational potential, informing novel, personalised symptom management techniques for these conditions, with the potential for better clinical outcomes.

TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry (ANZCTR), ACTRN12616001671459 . Registered on 5 December 2016.

Source: Macnamara CL, Cvejic E, Parker GB, Lloyd AR, Lee G, Beilharz JE, Vollmer-Conna U. Personalised relaxation practice to improve sleep and functioning in patients with chronic fatigue syndrome and depression: study protocol for a randomised controlled trial. Trials. 2018 Jul 11;19(1):371. doi: 10.1186/s13063-018-2763-8.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6042263/ (Full article)

Suicidal ideation in non-depressed individuals: The effects of a chronic, misunderstood illness

Abstract:

Chronic illness is a risk factor for suicide but is often explained with depression. Research has shown an increased suicide rate in patients with myalgic encephalomyelitis and chronic fatigue syndrome, but specific risk factors have been unexplored. We qualitatively analyzed responses from 29 patients who endorsed suicidal ideation but did not meet depression criteria.

Two themes were developed: (1) feeling trapped and (2) loss of self, loss of others, stigma and conflict. Myalgic encephalomyelitis and chronic fatigue syndrome caused patients severe disability, restructured their lives, and inflicted serious pain. Participants emphasized that they were not depressed, but felt trapped by the lack of treatments available.

Source: Devendorf AR, McManimen SL, Jason LA. Suicidal ideation in non-depressed individuals: The effects of a chronic, misunderstood illness. J Health Psychol. 2018 Jul 1:1359105318785450. doi: 10.1177/1359105318785450. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29992837

Reduced glycolytic reserve in isolated natural killer cells from Myalgic encephalomyelitis/chronic fatigue syndrome patients: A preliminary investigation

Abstract:

BACKGROUND: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is medically unexplained post-exertional fatigue associated with significant reduction in natural killer cell (NK) cytotoxicity activity. Cytotoxic activity relies on glycolytic flux and mitochondrial respiration to fulfill energetic cellular demands. While mitochondrial dysfunction has been reported in ME/CFS patients, no previous investigation has examined the bioenergetic profile of isolated NK cells from ME/CFS patients.

OBJECTIVE: This study was to determine the metabolic function in resting NK cells from ME/CFS patients.

METHOD: Six ME/CFS patients (aged 50.33±4.95) were age and sex-matched with non-fatigued healthy controls (aged 50.00±5.04). Mitochondrial stress tests measured parameters of mitochondrial function in the NK cells including basal respiration, ATP production, proton leak, maximal respiration, spare respiratory capacity and bioenergetic health index. Glycolytic stress tests measured parameters of glycolytic function such as glycolytic reserve, glycolysis and glycolytic capacity in isolated NK cells from ME/CFS patients and healthy controls using an extracellular flux analyzer, Seahorse XFp.

RESULT: There was a significant reduction of glycolytic reserve in resting NK cells from ME/CFS patients (0.6±0.07 mpH/ min) compared with healthy control (2.25±1.3 mpH/min). Mitochondrial respiration in resting NK cells did not approach statistical significance between ME/CFS patients and healthy controls.

CONCLUSION: These findings suggest resting NK cells from ME/CFS patients have reduced ability to increase glycolytic flux to respond to high energetic demands for ATP production. Hence, the reduced glycolytic reserves we have identified in isolated resting isolated NK cells should be further investigated to assist in understanding ME/CFS pathogenesis.

Source: Nguyen T, Staines D, Johnston S, Marshall-Gradisnik S. Reduced glycolytic reserve in isolated natural killer cells from Myalgic encephalomyelitis/chronic fatigue syndrome patients: A preliminary investigation. Asian Pac J Allergy Immunol. 2018 Jul 8. doi: 10.12932/AP-011117-0188. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29981562

Reduction of Glucocorticoid Receptor Function in Chronic Fatigue Syndrome

Abstract:

Glucocorticoid receptor (GR) function may have aetiopathogenic significance in chronic fatigue syndrome (CFS), via its essential role in mediating inflammatory responses as well as in hypothalamic-pituitary-adrenal axis regulation. GR function can be estimated ex vivo by measuring dexamethasone (dex) modulation of cytokine response to lipopolysaccharide (LPS), and in vivo using the impact of dex on cortisol levels. This study aimed to compare the GR function between CFS (n = 48), primary Sjögren’s syndrome (a disease group control) (n = 27), and sedentary healthy controls (HCs) (n = 20), and to investigate its relationship with clinical measures.

In the GR ex vivo response assay, whole blood was diluted and incubated with LPS (to stimulate cytokine production), with or without 10 or 100 nanomolar concentrations of dex. Cytometric bead array (CBA) and flow cytometry enabled quantification of cytokine levels (TNFα, interleukin- (IL-) 6, and IL-10) in the supernatants. In the in vivo response assay, five plasma samples were taken for determination of total cortisol concentration using ELISA at half-hourly intervals on two consecutive mornings separated by ingestion of 0.5 mg of dex at 11 pm. The association of the data from the in vivo and ex vivo analyses with reported childhood adversity was also examined.

CFS patients had reduced LPS-induced IL-6 and TNFα production compared to both control groups and reduced suppression of TNFα by the higher dose of dex compared to HCs. Cortisol levels, before or after dex, did not differ between CFS and HCs. Cortisol levels were more variable in CFS than HCs. In the combined group (CFS plus HC), cortisol concentrations positively and ex vivo GR function (determined by dex-mediated suppression of IL-10) negatively correlated with childhood adversity score.

The results do not support the hypothesis that GR dysregulation is aetiopathogenic in CFS and suggest that current and future endocrine cross-sectional studies in CFS may be vulnerable to the confounding influence of childhood trauma which is likely increased by comorbid depression.

Source: Lynn M, Maclachlan L, Finkelmeyer A, Clark J, Locke J, Todryk S, Ng WF, Newton JL, Watson S. Reduction of Glucocorticoid Receptor Function in Chronic Fatigue Syndrome. Mediators Inflamm. 2018 Jun 10;2018:3972104. doi: 10.1155/2018/3972104. eCollection 2018. https://www.ncbi.nlm.nih.gov/pubmed/29983634

Insights from metabolites get us closer to a test for chronic fatigue syndrome

Press Release: Columbia University’s Mailman School of Public Health, July 9, 2018. A study led by researchers at the Center for Infection and Immunity (CII) at Columbia University’s Mailman School of Public Health has identified a constellation of metabolites related to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Combining this data with data from an earlier microbiome study, the researchers now report they can predict whether or not someone has the disorder with a confidence of 84 percent.

The research team analyzed blood samples provided by 50 patients with ME/CFS and 50 controls matched for sex and age who were recruited at four clinical sites across the United States. Using mass spectrometry, a laboratory technique used to identify molecules by measuring their mass, the scientists found 562 metabolites — microscopic byproducts of human and microbial processes such as sugar, fat, and protein molecules. They excluded molecules related to antidepressants and other drugs patients might be taking.

Their metabolomics analysis, among the most detailed and meticulous to date, uncovered altered levels of metabolites, including choline, carnitine and several complex lipids present in patients with ME/CFS. The altered metabolites suggest dysfunction of the mitochrondria, the cellular powerplant, a finding in line with those reported by other research teams. Uniquely, the CII study also reports a second distinct pattern of metabolites in patients with ME/CFS and irritable bowel syndrome (IBS), matching earlier findings from their 2017 fecal microbiome study. Half of the patients with ME/CFS also had IBS.

When the researchers combined biomarkers from both the microbiome study and the new metabolome study, they reported a .836 predictive score, indicating an 84 percent certainty as to the presence of ME/CFS — better than with either study alone.

“This is a strong predictive model that suggests we’re getting close to the point where we’ll have lab tests that will allow us to say with a high level of certainty who has this disorder,” says first author Dorottya Nagy-Szakal, MD, PhD, a researcher at CII.

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Meta-analysis investigating post-exertional malaise between patients and controls

Abstract:

Post-exertional malaise is either required or included in many previously proposed case definitions of myalgic encephalomyelitis/chronic fatigue syndrome. A meta-analysis of odds ratios (ORs; association between patient status and post-exertional malaise status) and a number of potential moderators (i.e. study-level characteristics) of effect size were conducted.

Post-exertional malaise was found to be 10.4 times more likely to be associated with a myalgic encephalomyelitis/chronic fatigue syndrome diagnosis than with control status. Significant moderators of effect size included patient recruitment strategy and control selection. These findings suggest that post-exertional malaise should be considered a cardinal symptom of myalgic encephalomyelitis/chronic fatigue syndrome.

Source: Brown A, Jason LA. Meta-analysis investigating post-exertional malaise between patients and controls. J Health Psychol. 2018 Jul 1:1359105318784161. doi: 10.1177/1359105318784161. [Epub ahead of print]  https://www.ncbi.nlm.nih.gov/pubmed/29974812