Circulating microRNA expression signatures accurately discriminate myalgic encephalomyelitis from fibromyalgia and comorbid conditions

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and fibromyalgia (FM) are two chronic complex diseases with overlapping symptoms affecting multiple systems and organs over time. Due to the absence of validated biomarkers and similarity in symptoms, both disorders are misdiagnosed, and the comorbidity of the two is often unrecognized.

Our study aimed to investigate the expression profiles of 11 circulating miRNAs previously associated with ME/CFS pathogenesis in FM patients and individuals with a comorbid diagnosis of FM associated with ME/CFS (ME/CFS + FM), and matched sedentary healthy controls. Whether these 11 circulating miRNAs expression can differentiate between the two disorders was also examined.

Our results highlight differential circulating miRNAs expression signatures between ME/CFS, FM and ME/CFS + FM, which also correlate to symptom severity between ME/CFS and ME/CFS + FM groups. We provided a prediction model, by using a machine-learning approach based on 11 circulating miRNAs levels, which can be used to discriminate between patients suffering from ME/CFS, FM and ME/CFS + FM. These 11 miRNAs are proposed as potential biomarkers for discriminating ME/CFS from FM.

The results of this study demonstrate that ME/CFS and FM are two distinct illnesses, and we highlight the comorbidity between the two conditions. Proper diagnosis of patients suffering from ME/CFS, FM or ME/CFS + FM is crucial to elucidate the pathophysiology of both diseases, determine preventive measures, and establish more effective treatments.

Source: Nepotchatykh E, Caraus I, Elremaly W, Leveau C, Elbakry M, Godbout C, Rostami-Afshari B, Petre D, Khatami N, Franco A, Moreau A. Circulating microRNA expression signatures accurately discriminate myalgic encephalomyelitis from fibromyalgia and comorbid conditions. Sci Rep. 2023 Feb 2;13(1):1896. doi: 10.1038/s41598-023-28955-9. PMID: 36732593. https://www.nature.com/articles/s41598-023-28955-9 (Full text)

The Link Between Empty Sella Syndrome, Fibromyalgia, and Chronic Fatigue Syndrome: The Role of Increased Cerebrospinal Fluid Pressure

Abstract:

The etiopathogenesis of fibromyalgia (FM) and chronic fatigue syndrome (CFS) is not yet elucidated. Hypothalamo-pituitary-adrenal (HPA) axis dysfunction is reflected in the hormonal disturbances found in FM and CFS. Some study groups have introduced a novel hypothesis that moderate or intermittent intracranial hypertension may be involved in the etiopathogenesis of FM and CFS.

In these conditions, hormonal disturbances may be caused by the mechanical effect of increased cerebrospinal fluid pressure, which hampers blood flow in the pituitary gland. Severe intracranial pressure may compress the pituitary gland, resulting in primary empty sella (ES), potentially leading to pituitary hormone deficiencies.

The aim of this narrative review was to explore whether similar hormonal changes and symptoms exist between primary ES and FM or CFS and to link them to cerebrospinal fluid pressure dysregulation. A thorough search of the PubMed and Web of Science databases and the reference lists of the included studies revealed that several clinical characteristics were more prevalent in primary ES, FM or CFS patients than in controls, including increased cerebrospinal fluid pressure, obesity, female sex, headaches and migraine, fatigue, visual disturbances (visual acuity and eye motility abnormalities), vestibulocochlear disturbances (vertigo and neurosensorial hearing loss), and bodily pain (radicular pain and small-fiber neuropathy).

Furthermore, challenge tests of the pituitary gland showed similar abnormalities in all three conditions: blunted adrenocorticotropic hormone, cortisol, growth hormone, luteinizing hormone, and thyroid stimulating hormone responses and an increased prolactin response. The findings of this narrative review provide further support for the hypothesis that moderately or intermittently increased cerebrospinal fluid pressure is involved in the pathogenesis of FM and CFS and should stimulate further research into the etiopathogenesis of these conditions.

Source: Hulens M, Dankaerts W, Rasschaert R, Bruyninckx F, De Mulder P, Bervoets C. The Link Between Empty Sella Syndrome, Fibromyalgia, and Chronic Fatigue Syndrome: The Role of Increased Cerebrospinal Fluid Pressure. J Pain Res. 2023;16:205-219
https://doi.org/10.2147/JPR.S394321 https://www.dovepress.com/the-link-between-empty-sella-syndrome-fibromyalgia-and-chronic-fatigue-peer-reviewed-fulltext-article-JPR (Full text)

Autoantibody Correlation Signatures in Fibromyalgia and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Association with Symptom Severity

Abstract:

Background: Recent studies provide some evidence for the contribution of antibody-mediated autoimmune mechanisms to the nature of fibromyalgia (FM) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Much attention was paid to the autoantibodies (AAb) targeting G protein-coupled receptors as natural components of the immune system. However, natural AAb network is much more extensive, and has not been previously investigated in these disorders;

Methods: The enzyme immunoassays ELI-Viscero-Test and ELI-Neuro-Test were used to determine changes in serum content of a 33 natural AAb to neural, organ-specific and non-tissue-specific autoantigens a) in 11 FM patients with comorbid ME/CFS; b) in 11 ME/CFS patients without FM; c) in 11 healthy controls. Individual autoantibody profiles and their correlation with some clinical symptoms were analyzed.

Results: Both patients with ME/CFS and ME/CFS+FM were characterized by more frequent and pronounced deviations in the immunoreactivity to GABA-receptors than healthy controls. Although the level of other natural AAb did not differ between study groups, AAb correlation signatures were changing in patients compared to healthy controls. Both in patients and healthy controls the level of natural AAb to various neural and tissue-specific antigens correlated with the severity of fatigue, bodily pain, depression, anxiety, physical and mental-health related quality of life. Notably, that widely different correlation patterns were observed between study groups.

Conclusions: Findings from this pilot study provide some evidence that the homeostasis of autoimmune relationships, which are possibly a physiological part of our immune system, may break down in FM and ME/CFS. The correlation of disease-induced perturbations in individual AAb profiles with some clinical symptoms may arise from the immune system’s ability to reflect qualitative and quantitative changes in antigenic composition of the body.

Source: Ryabkova, V.A.; Gavrilova, N.Y.; Poletaeva, A.A.; Pukhalenko, A.I.; Koshkina, I.A.; Churilov, L.P.; Shoenfeld, Y. Autoantibody Correlation Signatures in Fibromyalgia and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Association with Symptom Severity . Preprints 2022, 2022120224 (doi: 10.20944/preprints202212.0224.v1). https://www.preprints.org/manuscript/202212.0224/v1 (Full text available as PDF file)

Fibromyalgia and Chronic Fatigue Syndromes: A systematic review and meta-analysis of cardiorespiratory fitness and neuromuscular function compared with healthy individuals

Abstract:

Objective: To determine cardiorespiratory fitness and neuromuscular function of people with CFS and FMS compared to healthy individuals.

Design: Systematic review and meta-analysis.

Data sources: PubMed, Medline, CINAHL, AMED, Cochrane Central Register of Controlled Trials (CENTRAL), and PEDro from inception to June 2022.

Eligible criteria for selecting studies: Studies were included if presenting baseline data on cardiorespiratory fitness and/or neuromuscular function from observational or interventional studies of patients diagnosed with FMS or CFS. Participants were aged 18 years or older, with results also provided for healthy controls. Risk of bias assessment was conducted using the Quality Assessment Tool for Quantitative Studies (EPHPP).

Results: 99 studies including 9853 participants (5808 patients; 4405 healthy controls) met our eligibility criteria. Random effects meta-analysis showed lower cardiorespiratory fitness (VO2max, anaerobic threshold, peak lactate) and neuromuscular function (MVC, fatigability, voluntary activation, muscle volume, muscle mass, rate of perceived exertion) in CFS and FMS compared to controls: all with moderate to high effect sizes.

Discussion: Our results demonstrate lower cardiorespiratory fitness and muscle function in those living with FMS or CFS when compared to controls. There were indications of dysregulated neuro-muscular interactions including heightened perceptions of effort, reduced ability to activate the available musculature during exercise and reduced tolerance of exercise.

Source: Zambolin F, Duro-Ocana P, Faisal A, Bagley L, Gregory WJ, Jones AW, McPhee JS. Fibromyalgia and Chronic Fatigue Syndromes: A systematic review and meta-analysis of cardiorespiratory fitness and neuromuscular function compared with healthy individuals. PLoS One. 2022 Oct 20;17(10):e0276009. doi: 10.1371/journal.pone.0276009. PMID: 36264901; PMCID: PMC9584387. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9584387/ (Full text)

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and fibromyalgia are indistinguishable by their cerebrospinal fluid proteomes

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and fibromyalgia have overlapping neurologic symptoms particularly disabling fatigue. This has given rise to the question whether they are distinct central nervous system (CNS) entities or is one an extension of the other. To investigate this, we used unbiased quantitative mass spectrometry-based proteomics to examine the most proximal fluid to the brain, cerebrospinal fluid (CSF). This was to ascertain if the proteome profile of one was the same or different from the other.

We examined two separate groups of ME/CFS, one with (n=15) and one without (n=15) fibromyalgia. We quantified a total of 2,083 proteins using immunoaffinity depletion, tandem mass tag isobaric labeling and offline two-dimensional liquid chromatography coupled to tandem mass spectrometry, including 1,789 that were quantified in all the CSF samples. ANOVA analysis did not yield any proteins with an adjusted p-value < 0.05. This supports the notion that ME/CFS and fibromyalgia as currently defined are not distinct entities.

Source: Steven E. SchutzerTao LiuChia-Feng TsaiVladislav A. PetyukAthena A. SchepmoesYi-Ting WangKarl K. WeitzJonas BergquistRichard D. SmithBenjamin H Natelson. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and fibromyalgia are indistinguishable by their cerebrospinal fluid proteomes.

Blunted short-term autonomic cardiovascular reactivity to orthostatic and clinostatic challenges in fibromyalgia as an indicator of the severity of chronic pain

Abstract:

Fibromyalgia is a long-term pain disorder that has been related to autonomic dysfunctions and reduced cardiovascular reactivity. We aimed to assess the dynamic short-term cardiovascular responses to postural changes in fibromyalgia. Thirty-eight women with fibromyalgia and thirty-six healthy women underwent the “Chronic Pain Autonomic Stress Test”.

Electrocardiogram, blood pressure and impedance cardiography were continuously recorded during active standing and lying down. Second-by-second values were derived over the first 30 s of each posture. Lower reactivity during the beginning of each position was observed in fibromyalgia sufferers compared to healthy women, with smaller responses seen during stand up in heart rate, blood pressure, cardiac output, total peripheral resistance, and pre-ejection period, and smaller changes during lying down in heart rate, cardiac output and total peripheral resistance. The magnitude of the autonomic adjustments to postural changes was inversely associated with the severity of clinical pain.

These findings indicate an early impaired autonomic cardiovascular response to orthostatic and clinostatic challenges in fibromyalgia, suggesting less autonomic flexibility and adaptability to situational demands and challenges. Short-term second-by-second cardiovascular measures may be useful in the clinical assessment of fibromyalgia.

Source: Contreras-Merino AM, Davydov DM, Galvez-Sánchez CM, Reyes Del Paso GA. Blunted short-term autonomic cardiovascular reactivity to orthostatic and clinostatic challenges in fibromyalgia as an indicator of the severity of chronic pain. Int J Psychophysiol. 2022 May;175:61-70. doi: 10.1016/j.ijpsycho.2022.03.001. Epub 2022 Mar 11. PMID: 35283267. https://www.sciencedirect.com/science/article/pii/S0167876022000599?via%3Dihub (Full text)

The autoimmune aetiology of unexplained chronic pain

Abstract:

Chronic pain is the leading cause of life years lived with disability worldwide. The aetiology of most chronic pain conditions has remained poorly understood and there is a dearth of effective therapies. The WHO ICD-11 has categorised unexplained chronic pain states as ‘chronic primary pains’ (CPP), which are further defined by their association with significant distress and/or dysfunction. The new mechanistic term, ‘nociplasticic pain’ has been developed to illustrate their presumed generation by a structurally intact, but abnormally functioning nociceptive system.

Recently, researchers have unravelled the surprising, ubiquitous presence of pain-sensitising autoantibodies in four investigated CPP indicating autoimmune causation. In persistent complex regional pain syndrome, fibromyalgia syndrome, chronic post-traumatic limb pain, and non-inflammatory joint pain associated with rheumatoid arthritis, passive transfer experiments have shown that either IgG or IgM antibodies from patient-donors cause symptoms upon injection to rodents that closely resemble those of the clinical disorders. Targets of antibody-binding and downstream effects vary between conditions, and more research is needed to elucidate the molecular and cellular details.

The central nervous system appears largely unaffected by antibody binding, suggesting that the clinically evident CNS symptoms associated with CPP might arise downstream of peripheral processes. In this narrative review pertinent findings are described, and it is suggested that additional symptom-based disorders might be examined for the contribution of antibody-mediated autoimmune mechanisms.

Source: Goebel A, Andersson D, Helyes Z, Clark JD, Dulake D, Svensson C. The autoimmune aetiology of unexplained chronic pain. Autoimmun Rev. 2022 Mar;21(3):103015. doi: 10.1016/j.autrev.2021.103015. Epub 2021 Dec 10. PMID: 34902604. https://www.sciencedirect.com/science/article/abs/pii/S1568997221002974 (Full text)

Genetic and epigenetic regulation of Catechol-O-methyltransferase in relation to inflammation in chronic fatigue syndrome and Fibromyalgia

Abstract:

Background: Catechol-O-methyltransferase (COMT) has been shown to influence clinical pain, descending modulation, and exercise-induced symptom worsening. COMT regulates nociceptive processing and inflammation, key pathophysiological features of Chronic Fatigue Syndrome and Fibromyalgia (CFS/FM). We aimed to determine the interactions between genetic and epigenetic mechanisms regulating COMT and its influence on inflammatory markers and symptoms in patients with CFS/FM.

Methods: A case-control study with repeated-measures design was used to reduce the chance of false positive and increase the power of our findings. Fifty-four participants (28 patients with CFS/FM and 26 controls) were assessed twice within 4 days. The assessment included clinical questionnaires, neurophysiological assessment (pain thresholds, temporal summation, and conditioned pain modulation), and blood withdrawal in order to assess rs4818, rs4633, and rs4680 COMT polymorphisms and perform haplotype estimation, DNA methylation in the COMT gene (both MB-COMT and S-COMT promoters), and cytokine expression (TNF-α, IFN-γ, IL-6, and TGF-β).

Results: COMT haplotypes were associated with DNA methylation in the S-COMT promoter, TGF-β expression, and symptoms. However, this was not specific for one condition. Significant between-group differences were found for increased DNA methylation in the MB-COMT promoter and decreased IFN-γ expression in patients.

Discussion: Our results are consistent with basic and clinical research, providing interesting insights into genetic-epigenetic regulatory mechanisms. MB-COMT DNA methylation might be an independent factor contributing to the pathophysiology of CFS/FM. Further research on DNA methylation in complex conditions such as CFS/FM is warranted. We recommend future research to employ a repeated-measure design to control for biomarkers variability and within-subject changes.

Source: Polli A, Hendrix J, Ickmans K, Bakusic J, Ghosh M, Monteyne D, Velkeniers B, Bekaert B, Nijs J, Godderis L. Genetic and epigenetic regulation of Catechol-O-methyltransferase in relation to inflammation in chronic fatigue syndrome and Fibromyalgia. J Transl Med. 2022 Oct 25;20(1):487. doi: 10.1186/s12967-022-03662-7. PMID: 36284330; PMCID: PMC9598022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9598022/ (Full text)

Cognitive task performance and subjective cognitive symptoms in individuals with Chronic Fatigue Syndrome or Fibromyalgia: A cross-sectional analysis of the Lifelines cohort study

Abstract:

Objective: This study examined cognitive task performance and self-reported cognitive functioning in individuals with chronic fatigue syndrome (CFS) and fibromyalgia (FM) in a population-based sample and investigated the role of mood and anxiety disorders as well as severity of the physical symptoms.

Methods: This study was performed in 79,966 participants (Mean age: 52.9, SD = ±12.6 years, 59.2% women) from the Lifelines general-population. Symptoms consistent with the diagnostic criteria for CFS and FM were assessed using questionnaires. Two comparison groups were used: participants with self-reported medical disorders with well-defined pathophysiology (i.e., multiple sclerosis and rheumatic arthritis) and controls without these diseases. Objective task-performance was based on the computerized CogState cognitive battery and subjective cognitive symptoms using the concentration subscale of the Checklist Individual Strength.

Results: Cognitive task performance was poorer in individuals with CFS vs. controls without disease and controls with a medical disorder, although the severity of cognitive dysfunction was mild. Participants meeting criteria for CFS (n = 2,461) or FM (n = 4,295) reported more subjective cognitive symptoms compared to controls without a medical disorder (d = 1.53, 95%CI = 1.49-1.57 for CFS; d = 1.25, 95%CI = 1.22-1.29 for FM) and participants with a medical disease (d = 0.62, 95%CI = 0.46-0.79 for CFS; d = 0.75, 95%CI = 0.70-0.80 for FM). These differences remained essentially the same when excluding participants with comorbid mood or anxiety disorders or adjusting for physical symptom severity.

Conclusions: Subjective cognitive symptoms and to a lesser extent suboptimal cognitive task performance are more prevalent in individuals with CFS or FM compared to controls without these conditions.

Source: Joustra ML, Hartman CA, Bakker SJL, Rosmalen JGM. Cognitive task performance and subjective cognitive symptoms in individuals with Chronic Fatigue Syndrome or Fibromyalgia: A cross-sectional analysis of the Lifelines cohort study. Psychosom Med. 2022 Aug 2. doi: 10.1097/PSY.0000000000001117. Epub ahead of print. PMID: 35980775.  https://pubmed.ncbi.nlm.nih.gov/35980775/

Altered serum bile acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity

Abstract:

Alterations in the composition and function of the gut microbiome in women with fibromyalgia have recently been demonstrated, including changes in the relative abundance of certain bile acid metabolizing bacteria. Bile acids can affect multiple physiological processes, including visceral pain, but have yet to be explored for association to the fibromyalgia gut microbiome. In this study, 16S rRNA sequencing and targeted metabolomic approaches were used to characterize the gut microbiome and circulating bile acids in a cohort of 42 women with fibromyalgia and 42 healthy controls.

Alterations in the relative abundance of several bacterial species known to metabolize bile acids were observed in women with fibromyalgia, accompanied by significant alterations in the serum concentration of secondary bile acids, including a marked depletion of α-muricholic acid. Statistical learning algorithms could accurately detect individuals with fibromyalgia using the concentration of these serum bile acids. Serum α-muricholic acid was highly correlated with symptom severity, including pain intensity and fatigue.

Taken together, these findings suggest serum bile acid alterations are implicated in nociplastic pain. The changes observed in the composition of the gut microbiota and the concentration of circulating secondary bile acids seem congruent with the phenotype of increased nociception, and are quantitatively correlated with symptom severity.

This is a first demonstration of circulating bile acid alteration in individuals with fibromyalgia, potentially secondary to upstream gut microbiome alterations. If corroborated in independent studies, these observations may allow for the development of molecular diagnostic aids for fibromyalgia as well as mechanistic insights into the syndrome.

Source: Minerbi A, Gonzalez E, Brereton N, Fitzcharles MA, Chevalier S, Shir Y. Altered serum bile acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity. Pain. 2022 May 19. doi: 10.1097/j.pain.0000000000002694. Epub ahead of print. PMID: 35587528. https://pubmed.ncbi.nlm.nih.gov/35587528/