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

Abstract:

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.

Source: Wirth KJ, Scheibenbogen C. Pathophysiology of skeletal muscle disturbances in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). J Transl Med. 2021 Apr 21;19(1):162. doi: 10.1186/s12967-021-02833-2. PMID: 33882940.  https://pubmed.ncbi.nlm.nih.gov/33882940/

Hand grip strength and fatigability: correlation with clinical parameters and diagnostic suitability in ME/CFS

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex and debilitating disease accompanied by muscular fatigue and pain. A functional measure to assess muscle fatigability of ME/CFS patients is, however, not established in clinical routine. The aim of this study is to evaluate by assessing repeat maximum handgrip strength (HGS), muscle fatigability as a diagnostic tool and its correlation with clinical parameters.

Methods: We assessed the HGS of 105 patients with ME/CFS, 18 patients with Cancer related fatigue (CRF) and 66 healthy controls (HC) using an electric dynamometer assessing maximal (Fmax) and mean force (Fmean) of ten repetitive measurements. Results were correlated with clinical parameters, creatinine kinase (CK) and lactate dehydrogenase (LDH). Further, maximum isometric quadriceps strength measurement was conducted in eight ME/CFS patients and eight HC.

Results: ME/CFS patients have a significantly lower Fmax and Fmean HGS compared to HC (p < 0.0001). Further, Fatigue Ratio assessing decline in strength during repeat maximal HGS measurement (Fmax/Fmean) was higher (p ≤ 0.0012). The Recovery Ratio after an identical second testing 60 min later was significantly lower in ME/CFS compared to HC (Fmean2/Fmean1; p ≤ 0.0020). Lower HGS parameters correlated with severity of disease, post-exertional malaise and muscle pain and with higher CK and LDH levels after exertion.

Conclusion: Repeat HGS assessment is a sensitive diagnostic test to assess muscular fatigue and fatigability and an objective measure to assess disease severity in ME/CFS.

Source: Jäkel B, Kedor C, Grabowski P, Wittke K, Thiel S, Scherbakov N, Doehner W, Scheibenbogen C, Freitag H. Hand grip strength and fatigability: correlation with clinical parameters and diagnostic suitability in ME/CFS. J Transl Med. 2021 Apr 19;19(1):159. doi: 10.1186/s12967-021-02774-w. PMID: 33874961. https://pubmed.ncbi.nlm.nih.gov/33874961/

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. 2020 Nov-Dec;25(13-14):2106-2117. doi: 10.1177/1359105318785450. Epub 2018 Jul 11. PMID: 29992837. https://pubmed.ncbi.nlm.nih.gov/29992837/

Overcoming this is going to be difficult: Suicide risk, stigma, and chronic fatigue syndrome

Our findings revealed two broad themes in patients’ experiences with ME and CFS and suicidal ideation. The first theme captures how patients felt trapped by their illness. Many patients said they had no access to adequate resources, like a supportive friend or physician, to help them manage their illness. This sentiment was coupled with feeling hopeless about recovering from their disorder. Patients stated that many physicians wrongly think that ME and CFS are mental health conditions – when they are physical illnesses – which leads physicians to recommend inappropriate treatments like talk therapy.

Read the full  article HERE.

Original Article: Devendorf A. R., McManimen S. L., Jason L. A. Suicidal ideation in non-depressed individuals: The effects of a chronic, misunderstood illness. Journal of Health Psychology. 25(13-14), 2106-2117 (2020). https://pubmed.ncbi.nlm.nih.gov/29992837/

Exploring anhedonia in adolescents with Chronic Fatigue Syndrome (CFS): A mixed-methods study

Abstract:

Background: Chronic Fatigue Syndrome (CFS/ME) may get in the way of enjoying activities. A substantial minority of adolescents with CFS/ME are depressed. Anhedonia is a core symptom of depression. Anhedonia in adolescents with CFS/ME has not been previously investigated.

Method: One hundred and sixty-four adolescents, age 12 to 18, with CFS/ME completed a diagnostic interview (K-SADS) and questionnaires (HADS, RCADS). We used a mixed-methods approach to explore the experience of anhedonia and examine how common it is, comparing those with clinically significant anhedonia to those without.

Results: Forty-two percent of adolescents with CFS/ME reported subclinical or clinical levels of anhedonia. Fifteen percent had clinically significant anhedonia. Thematic analysis generated two themes: (1) stopping activities that they previously enjoyed and (2) CFS/ME obstructs enjoyment. Most (72%) of those who reported clinically significant anhedonia met the depression diagnostic criteria. Those who were depressed used more negative language to describe their experience of activities than in those who were not depressed, although the themes were broadly similar.

Conclusions: Experiencing pleasure from activities may be affected in CFS/ME, particularly in those who are depressed. Anhedonia may get in the way of behavioural strategies used within CFS/ME treatments.

Source: Smith L, Crawley E, Riley M, McManus M, Loades ME. Exploring anhedonia in adolescents with Chronic Fatigue Syndrome (CFS): A mixed-methods study. Clin Child Psychol Psychiatry. 2021 Apr 16:13591045211005515. doi: 10.1177/13591045211005515. Epub ahead of print. PMID: 33863235. https://pubmed.ncbi.nlm.nih.gov/33863235/

Potential role of microbiome in Chronic Fatigue Syndrome/Myalgic Encephalomyelits

Abstract:

Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is a severe multisystemic disease characterized by immunological abnormalities and dysfunction of energy metabolism. Recent evidences suggest strong correlations between dysbiosis and pathological condition. The present research explored the composition of the intestinal and oral microbiota in CFS/ME patients as compared to healthy controls. The fecal metabolomic profile of a subgroup of CFS/ME patients was also compared with the one of healthy controls. The fecal and salivary bacterial composition in CFS/ME patients was investigated by Illumina sequencing of 16S rRNA gene amplicons. The metabolomic analysis was performed by an UHPLC-MS.

The fecal microbiota of CFS/ME patients showed a reduction of Lachnospiraceae, particularly Anaerostipes, and an increased abundance of genera Bacteroides and Phascolarctobacterium compared to the non-CFS/ME groups. The oral microbiota of CFS/ME patients showed an increase of Rothia dentocariosa. The fecal metabolomic profile of CFS/ME patients revealed high levels of glutamic acid and argininosuccinic acid, together with a decrease of alpha-tocopherol. Our results reveal microbial signatures of dysbiosis in the intestinal microbiota of CFS/ME patients. Further studies are needed to better understand if the microbial composition changes are cause or consequence of the onset of CFS/ME and if they are related to any of the several secondary symptoms.

Source: Lupo, G.F.D., Rocchetti, G., Lucini, L. et al. Potential role of microbiome in Chronic Fatigue Syndrome/Myalgic Encephalomyelits (CFS/ME). Sci Rep 11, 7043 (2021). https://doi.org/10.1038/s41598-021-86425-6 https://www.nature.com/articles/s41598-021-86425-6 (Full text)

Case Report Life-Threatening Malnutrition in Very Severe ME/CFS

Abstract:

Very severe Myalgic Encephalomyelitis (ME), (also known as Chronic Fatigue Syndrome) can lead to problems with nutrition and hydration. The reasons can be an inability to swallow, severe gastrointestinal problems tolerating food or the patient being too debilitated to eat and drink. Some patients with very severe ME will require tube feeding, either enterally or parenterally. There can often be a significant delay in implementing this, due to professional opinion, allowing the patient to become severely malnourished. Healthcare professionals may fail to recognize that the problems are a direct consequence of very severe ME, preferring to postulate psychological theories rather than addressing the primary clinical need. We present five case reports in which delay in instigating tube feeding led to severe malnutrition of a life-threatening degree. This case study aims to alert healthcare professionals to these realities.

Source: Helen Baxter, Nigel Speight, andWilliam Weir. Case Report Life-Threatening Malnutrition in Very Severe ME/CFS. Healthcare 2021, 9(4), 459; https://doi.org/10.3390/healthcare9040459  https://www.mdpi.com/2227-9032/9/4/459 (Full text)

Long-COVID syndrome-associated brain fog and chemofog: Luteolin to the rescue

Abstract:

COVID-19 leads to severe respiratory problems, but also to long-COVID syndrome associated primarily with cognitive dysfunction and fatigue. Long-COVID syndrome symptoms, especially brain fog, are similar to those experienced by patients undertaking or following chemotherapy for cancer (chemofog or chemobrain), as well in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or mast cell activation syndrome (MCAS). The pathogenesis of brain fog in these illnesses is presently unknown but may involve neuroinflammation via mast cells stimulated by pathogenic and stress stimuli to release mediators that activate microglia and lead to inflammation in the hypothalamus. These processes could be mitigated by phytosomal formulation (in olive pomace oil) of the natural flavonoid luteolin.

Source: Theoharides TC, Cholevas C, Polyzoidis K, Politis A. Long-COVID syndrome-associated brain fog and chemofog: Luteolin to the rescue. Biofactors. 2021 Apr 12. doi: 10.1002/biof.1726. Epub ahead of print. PMID: 33847020. https://pubmed.ncbi.nlm.nih.gov/33847020/

Recovery from chronic fatigue syndrome: a systematic review-heterogeneity of definition limits study comparison

Abstract:

Background: Paediatric chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) is a common illness with a major impact on quality of life. Recovery is poorly understood. Our aim was to describe definitions of recovery in paediatric CFS/ME, the rate of recovery and the time to recovery.

Methods: This systematic review included a detailed search of MEDLINE, EMBASE, PsycInfo and Cochrane Library between 1994 and July 2018. Inclusion criteria were (1) clinical trials and observational studies, (2) participants aged <19 years with CFS/ME, (3) conducted in Western Healthcare systems and (4) studies including a measure of recovery and time taken to recover.

Results: Twelve papers (10 studies) were identified, involving 826 patients (range 23-135). Recovery rates were highly varied, ranging between 4.5% and 83%.Eleven distinct definitions of recovery were used; six were composite outcomes while five used unidimensional outcomes. Outcome measures used to define recovery were highly heterogeneous. School attendance (n=8), fatigue (n=6) and physical functioning (n=4) were the most common outcomes included in definition of recovery. Only five definitions included a personal measure of recovery.

Implications: Definitions of recovery are highly variable, likely secondary to differences in study design, outcomes used, follow-up and study populations. Heterogeneous definitions of recovery limit meaningful comparison between studies, highlighting the need for a consensus definition going forward. Recovery is probably best defined from the child’s own perspective with a single self-reported measure. If composite measures are used for research, there should be agreement on the core outcome set used.

Source: Moore Y, Serafimova T, Anderson N, King H, Richards A, Brigden A, Sinai P, Higgins J, Ascough C, Clery P, Crawley EM. Recovery from chronic fatigue syndrome: a systematic review-heterogeneity of definition limits study comparison. Arch Dis Child. 2021 Apr 12:archdischild-2020-320196. doi: 10.1136/archdischild-2020-320196. Epub ahead of print. PMID: 33846138. https://pubmed.ncbi.nlm.nih.gov/33846138/

Response to Adamson et al. (2020): ‘Cognitive behavioural therapy for chronic fatigue and chronic fatigue syndrome: Outcomes from a specialist clinic in the UK’

Abstract:

In a paper published in the Journal of the Royal Society of Medicine, Adamson et al. (2020) interpret data as showing that cognitive behavioural therapy leads to improvement in patients with chronic fatigue syndrome and chronic fatigue. Their research is undermined by several methodological limitations, including: (a) sampling ambiguity; (b) weak measurement; (c) survivor bias; (d) missing data and (e) lack of a control group. Unacknowledged sample attrition renders statements in the published Abstract misleading with regard to points of fact. That the paper was approved by peer reviewers and editors illustrates how non-rigorous editorial processes contribute to systematic publication bias.

Source: Hughes BM, Tuller D. Response to Adamson et al. (2020): ‘Cognitive behavioural therapy for chronic fatigue and chronic fatigue syndrome: Outcomes from a specialist clinic in the UK’. J Health Psychol. 2021 Apr 10:13591053211008203. doi: 10.1177/13591053211008203. Epub ahead of print. PMID: 33840241. https://pubmed.ncbi.nlm.nih.gov/33840241/