Evidence of widespread metabolite abnormalities in Myalgic encephalomyelitis/chronic fatigue syndrome: assessment with whole-brain magnetic resonance spectroscopy

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, debilitating disease characterised by a wide range of symptoms that severely impact all aspects of life. Despite its significant prevalence, ME/CFS remains one of the most understudied and misunderstood conditions in modern medicine. ME/CFS lacks standardised diagnostic criteria owing to variations in both inclusion and exclusion criteria across different diagnostic guidelines, and furthermore, there are currently no effective treatments available. Moving beyond the traditional fragmented perspectives that have limited our understanding and management of the disease, our analysis of current information on ME/CFS represents a significant paradigm shift by synthesising the disease's multifactorial origins into a cohesive model. We discuss how ME/CFS emerges from an intricate web of genetic vulnerabilities and environmental triggers, notably viral infections, leading to a complex series of pathological responses including immune dysregulation, chronic inflammation, gut dysbiosis, and metabolic disturbances. This comprehensive model not only advances our understanding of ME/CFS's pathophysiology but also opens new avenues for research and potential therapeutic strategies. By integrating these disparate elements, our work emphasises the necessity of a holistic approach to diagnosing, researching, and treating ME/CFS, urging the scientific community to reconsider the disease's complexity and the multifaceted approach required for its study and management.

Unravelling shared mechanisms: insights from recent ME/CFS research to illuminate long COVID pathologies

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic illness often triggered by an initiating acute event, mainly viral infections. The transition from acute to chronic disease remains unknown, but interest in this phenomenon has escalated since the COVID-19 pandemic and the post-COVID-19 illness, termed 'long COVID' (LC). Both ME/CFS and LC share many clinical similarities. Here, we present recent findings in ME/CFS research focussing on proposed disease pathologies shared with LC. Understanding these disease pathologies and how they influence each other is key to developing effective therapeutics and diagnostic tests. Given that ME/CFS typically has a longer disease duration compared with LC, with symptoms and pathologies evolving over time, ME/CFS may provide insights into the future progression of LC.

Detection of Neuroinflammation Induced by Typhoid Vaccine Using Quantitative Magnetization Transfer MR: A Randomized Crossover Study

BACKGROUND

The role of neuroinflammation in psychiatric disorders is not well-elucidated. A noninvasive technique sensitive to low-level neuroinflammation may improve understanding of the pathophysiology of these conditions.

PURPOSE

To test the ability of quantitative magnetization transfer (QMT) MR at 3 T for detection of low-level neuroinflammation induced by typhoid vaccine within a clinically reasonable scan time.

STUDY TYPE

Randomized, crossover, placebo-controlled.

SUBJECTS

Twenty healthy volunteers (10 males; median age 34 years).

FIELD STRENGTH/SEQUENCE

Magnetization prepared rapid gradient-echo and MT-weighted 3D fast low-angle shot sequences at 3 T.

ASSESSMENT

Participants were randomized to either vaccine or placebo first with imaging, then after a washout period received the converse with a second set of imaging. MT imaging, scan time, and blood-based inflammatory marker concentrations were assessed pre- and post-vaccine and placebo. Mood was assessed hourly using the Profile of Mood States questionnaire. QMT parameter maps, including the exchange rate from bound to free pool (kba) were generated using a two-pool model and then segmented into tissue type.

STATISTICAL TESTS

Voxel-wise permutation-based analysis examined inflammatory-related alterations of QMT parameters. The threshold-free cluster enhancement method with family-wise error was used to correct voxel-wise results for multiple comparisons. Region of interest averages were fed into mixed models and Bonferroni corrected. Spearman correlations assessed the relationship between mood scores and QMT parameters. Results were considered significant if corrected P < 0.05.

RESULTS

Scan time for the MT-weighted acquisition was approximately 11 minutes. Blood-based analysis showed higher IL-6 concentrations post-vaccine compared to post-placebo. Voxel-wise analysis found three clusters indicating an inflammatory-mediated increase in kba in cerebellar white matter. Cerebellar kba for white matter was negatively associated with vigor post-vaccine but not post-placebo.

DATA CONCLUSION

This study suggested that QMT at 3 T may show some sensitivity to low-level neuroinflammation. Further studies are needed to assess the viability of QMT for use in inflammatory-based disorders.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

Traumatic Brain Injury Outcomes After Recreational Cannabis Use

Purpose

Basic science data indicate potential neuroprotective effects of cannabinoids in traumatic brain injury (TBI). We aimed to evaluate the effects of pre-TBI recreational cannabis use on TBI outcomes.

Patients and Methods

We used i2b2 (a scalable informatics framework; www.i2b2.org) to identify all patients presenting with acute TBI between 1/1/2014 and 12/31/2016, then conducted a double-abstraction medical chart review to compile basic demographic, urine drug screen (UDS), Glasgow Coma Scale (GCS), and available outcomes data (mortality, modified Rankin Scale (mRS), duration of stay, disposition (home, skilled nursing facility, inpatient rehabilitation, other)) at discharge and at specific time points thereafter. We conducted multivariable nested ordinal and logistic regression analyses to estimate associations between cannabis use, other UDS results, demographic factors, and selected outcomes.

Results

i2b2 identified 6396 patients who acutely presented to our emergency room with TBI. Of those, 3729 received UDS, with 22.2% of them testing positive for cannabis. Mortality was similar in patients who tested positive vs negative for cannabis (3.9% vs 4.8%; p = 0.3) despite more severe GCS on admission in the cannabis positive group (p = 0.045). Several discharge outcome measures favored the cannabis positive group who had a higher rate of discharge home vs other care settings (p < 0.001), lower discharge mRS (p < 0.001), and shorter duration of hospital stay (p < 0.001) than the UDS negative group. Multivariable analyses confirmed mostly independent associations between positive cannabis screen and these post-TBI short- and long-term outcomes.

Conclusion

This study adds evidence about the potentially neuroprotective effects of recreational cannabis for short- and long-term post-TBI outcomes. These results need to be confirmed via prospective data collections.

Metabolomic and immune alterations in long COVID patients with chronic fatigue syndrome

Introduction

A group of SARS-CoV-2 infected individuals present lingering symptoms, defined as long COVID (LC), that may last months or years post the onset of acute disease. A portion of LC patients have symptoms similar to myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), which results in a substantial reduction in their quality of life. A better understanding of the pathophysiology of LC, in particular, ME/CFS is urgently needed.

Methods

We identified and studied metabolites and soluble biomarkers in plasma from LC individuals mainly exhibiting ME/CFS compared to age-sex-matched recovered individuals (R) without LC, acute COVID-19 patients (A), and to SARS-CoV-2 unexposed healthy individuals (HC).

Results

Through these analyses, we identified alterations in several metabolomic pathways in LC vs other groups. Plasma metabolomics analysis showed that LC differed from the R and HC groups. Of note, the R group also exhibited a different metabolomic profile than HC. Moreover, we observed a significant elevation in the plasma pro-inflammatory biomarkers (e.g. IL-1α, IL-6, TNF-α, Flt-1, and sCD14) but the reduction in ATP in LC patients. Our results demonstrate that LC patients exhibit persistent metabolomic abnormalities 12 months after the acute COVID-19 disease. Of note, such metabolomic alterations can be observed in the R group 12 months after the acute disease. Hence, the metabolomic recovery period for infected individuals with SARS-CoV-2 might be long-lasting. In particular, we found a significant reduction in sarcosine and serine concentrations in LC patients, which was inversely correlated with depression, anxiety, and cognitive dysfunction scores.

Conclusion

Our study findings provide a comprehensive metabolomic knowledge base and other soluble biomarkers for a better understanding of the pathophysiology of LC and suggests sarcosine and serine supplementations might have potential therapeutic implications in LC patients. Finally, our study reveals that LC disproportionally affects females more than males, as evidenced by nearly 70% of our LC patients being female.

Brain Temperature as an Indicator of Cognitive Function in Traumatic Brain Injury Patients

Whether brain temperature noninvasively extracted by magnetic resonance imaging has a role in identifying brain changes in the later phases of mild to moderate traumatic brain injury (TBI) is not known. This prospective study aimed to evaluate if TBI patients in subacute and chronic phases had altered brain temperature measured by whole-brain magnetic resonance spectroscopic imaging (WB-MRSI) and if the measurable brain temperature had any relationship with cognitive function scores. WB-MRSI was performed on eight TBI patients and fifteen age- and sex-matched control subjects. Brain temperature (T) was extracted from the brain's major metabolites and compared between the two groups. The T of the patients was tested for correlation with cognitive function test scores. The results showed significantly lower brain temperature in the TBI patients (p < 0.05). Brain temperature derived from N-acetylaspartate (TNAA) strongly correlated with the 2 s paced auditory serial addition test (PASAT-2s) score (p < 0.05). The observation of lower brain temperature in TBI patients may be due to decreased metabolic activity resulting from glucose and oxygen depletion. The correlation of brain temperature with PASAT-2s may imply that noninvasive brain temperature may become a noninvasive index reflecting cognitive performance.

Repetitive transcranial magnetic stimulation ameliorates symptoms in patients with myalgic encephalomyelitis (chronic fatigue syndrome)

Background

Central nervous system dysfunction has been postulated to cause debilitating symptoms in patients with myalgic encephalomyelitis (ME) (originally called "chronic fatigue syndrome"). Repetitive transcranial magnetic stimulation (rTMS) is a newly developed neuromodulatory procedure and has been suggested to facilitate the cortical neural activity.

Methods

This study enrolled 30 patients with ME (7 men and 23 women) with a mean age of 39 ± 12 years, who received rTMS treatment of both the left dorsolateral prefrontal cortex and the left primary motor area in the brain. The performance status score (0-9) for restricting activities of daily living, orthostatic intolerance (OI) during a 10-min standing test, neurologic disequilibrium diagnosed as unstable standing with their feet together and eyes closed, neuropathic pain or fibromyalgia, and muscle weakness were compared before and after treatment.

Results

After therapy, favorable effects were observed with a decrease in performance status score or index for restriction of activities of daily living of ≥ 2 points in 20 patients (67%). OI with the inability to complete the 10-min standing test was resolved in 10 (83%) out of 12 patients, and disequilibrium was resolved in 15 (88%) out of 17 patients. Neuropathic pain or fibromyalgia was attenuated in seven (70%) out of 10 patients. Muscle weakness with grip power of < 10 kg was resolved in two (50%) out of four patients. No untoward effects were encountered in all the study patients.

Conclusion

The treatment with rTMS is effective in alleviating various symptoms, especially OI and disequilibrium, and in improving the activities of daily living in patients with ME.

Unique immune and inflammatory cytokine profiles may define long COVID syndrome

PURPOSE

Long COVID is estimated to occur in 5-10% of individuals after acute SARS-CoV-2 infection. However, the pathophysiology driving the disease process is poorly understood.

METHODS

We evaluated urine and plasma inflammatory and immune cytokine profiles in 33 individuals with long COVID compared to 33 who were asymptomatic and recovered, and 34 without prior infection.

RESULTS

Mean urinary leukotriene E4 was significantly elevated among individuals with long COVID compared to asymptomatic and recovered individuals (mean difference 774.2 pg/mL; SD 335.7) and individuals without prior SARS-CoV-2 infection (mean difference 503.1 pg/ml; SD 467.7). Plasma chemokine ligand 6 levels were elevated among individuals with long COVID compared to individuals with no prior SARS-CoV-2 infection (mean difference 0.59 units; SD 0.42). We found no significant difference in angiotensin-converting enzyme 2 antibody levels. Plasma tumor necrosis factor receptor-associated factor 2 (TRAF2) levels were reduced among individuals with long COVID compared to individuals who were asymptomatic and recovered (mean difference = 0.6 units, SD 0.46). Similarly, the mean level of Sarcoma Homology 2-B adapter protein 3 was 3.3 units (SD 1.24) among individuals with long COVID, lower than 4.2 units (SD 1.1) among individuals with recovered, asymptomatic COVID.

CONCLUSION

Our findings suggest that further studies should be conducted to evaluate the role of leukotriene E4 as a potential biomarker for a diagnostic test. Furthermore, based on reductions in TRAF2, long COVID may be driven in part by impaired TRAF2-dependent immune-mediated inflammation and potentially immune exhaustion.

Developing a Blood Cell-Based Diagnostic Test for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Using Peripheral Blood Mononuclear Cells

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by debilitating fatigue that profoundly impacts patients' lives. Diagnosis of ME/CFS remains challenging, with most patients relying on self-report, questionnaires, and subjective measures to receive a diagnosis, and many never receiving a clear diagnosis at all. In this study, a single-cell Raman platform and artificial intelligence are utilized to analyze blood cells from 98 human subjects, including 61 ME/CFS patients of varying disease severity and 37 healthy and disease controls. These results demonstrate that Raman profiles of blood cells can distinguish between healthy individuals, disease controls, and ME/CFS patients with high accuracy (91%), and can further differentiate between mild, moderate, and severe ME/CFS patients (84%). Additionally, specific Raman peaks that correlate with ME/CFS phenotypes and have the potential to provide insights into biological changes and support the development of new therapeutics are identified. This study presents a promising approach for aiding in the diagnosis and management of ME/CFS and can be extended to other unexplained chronic diseases such as long COVID and post-treatment Lyme disease syndrome, which share many of the same symptoms as ME/CFS.

Chronic inflammation, neuroglial dysfunction, and plasmalogen deficiency as a new pathobiological hypothesis addressing the overlap between post-COVID-19 symptoms and myalgic encephalomyelitis/chronic fatigue syndrome

After five waves of coronavirus disease 2019 (COVID-19) outbreaks, it has been recognized that a significant portion of the affected individuals developed long-term debilitating symptoms marked by chronic fatigue, cognitive difficulties ("brain fog"), post-exertional malaise, and autonomic dysfunction. The onset, progression, and clinical presentation of this condition, generically named post-COVID-19 syndrome, overlap significantly with another enigmatic condition, referred to as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Several pathobiological mechanisms have been proposed for ME/CFS, including redox imbalance, systemic and central nervous system inflammation, and mitochondrial dysfunction. Chronic inflammation and glial pathological reactivity are common hallmarks of several neurodegenerative and neuropsychiatric disorders and have been consistently associated with reduced central and peripheral levels of plasmalogens, one of the major phospholipid components of cell membranes with several homeostatic functions. Of great interest, recent evidence revealed a significant reduction of plasmalogen contents, biosynthesis, and metabolism in ME/CFS and acute COVID-19, with a strong association to symptom severity and other relevant clinical outcomes. These bioactive lipids have increasingly attracted attention due to their reduced levels representing a common pathophysiological manifestation between several disorders associated with aging and chronic inflammation. However, alterations in plasmalogen levels or their lipidic metabolism have not yet been examined in individuals suffering from post-COVID-19 symptoms. Here, we proposed a pathobiological model for post-COVID-19 and ME/CFS based on their common inflammation and dysfunctional glial reactivity, and highlighted the emerging implications of plasmalogen deficiency in the underlying mechanisms. Along with the promising outcomes of plasmalogen replacement therapy (PRT) for various neurodegenerative/neuropsychiatric disorders, we sought to propose PRT as a simple, effective, and safe strategy for the potential relief of the debilitating symptoms associated with ME/CFS and post-COVID-19 syndrome.

Suppressed immune and metabolic responses to intestinal damage-associated microbial translocation in myalgic encephalomyelitis/chronic fatigue syndrome

The etiology and mechanism of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are poorly understood and no biomarkers have been established. Specifically, the relationship between the immunologic, metabolic, and gastrointestinal abnormalities associated with ME/CFS and their relevance to established symptoms of the condition remain unclear. Relying on data from two independent pairs of ME/CFS and control cohorts, one at rest and one undergoing an exercise challenge, we identify a state of suppressed acute-phase innate immune response to microbial translocation in conjunction with a compromised gut epithelium in ME/CFS. This immunosuppression, along with observed enhancement of compensatory antibody responses to counter the microbial translocation, was associated with and may be mediated by alterations in glucose and citrate metabolism and an IL-10 immunoregulatory response. Our findings provide novel insights into mechanistic pathways, biomarkers, and potential therapeutic targets in ME/CFS, including in the context of exertion, with relevance to both intestinal and extra-intestinal symptoms.

Abnormal immune system response in the brain of women with Fibromyalgia after experimental endotoxin challenge

Background

The pathophysiology of fibromyalgia (FM) is thought to include an overactive immune system, leading to central nervous system sensitization, allodynia, and hyperalgesia. We aimed to test this theory using an experimental immune system activation procedure and neuroimaging with magnetic resonance spectroscopic imaging (MRSI).

Methods

Twelve women with FM and 13 healthy women (healthy controls; HC) received 0.3 or 0.4 ng/kg endotoxin and underwent MRSI before and after the infusion. Changes in brain levels of choline (CHO), myo-inositol (MI), N-Acetylaspartate (NAA), and MRSI-derived brain temperature were compared between groups and dosage levels using mixed analyses of variance.

Results

Significant group-by-time interactions in brain temperature were found in the right thalamus. Post-hoc testing revealed that brain temperature increased by 0.55 °C in the right thalamus in FM (t(10) = -3.483, p = 0.006), but not in HCs (p > 0.05). Dose-by-time interactions revealed brain temperature increases in the right insula after 0.4 ng/kg (t(12) = -4.074, p = 0.002), but not after 0.3 ng/kg (p > 0.05). Dose-by-time interactions revealed decreased CHO in the right Rolandic operculum after 0.4 ng/kg endotoxin (t(13) = 3.242, p = 0.006) but not 0.3 ng/kg. In the left paracentral lobule, CHO decreased after 0.3 ng/kg (t(9) = 2.574, p = 0.030) but not 0.4 ng/kg. Dose-by-time interactions affected MI in several brain regions. MI increased after 0.3 ng/kg in the right Rolandic operculum (t(10) = -2.374, p = 0.039), left supplementary motor area (t(9) = -2.303, p = 0.047), and left occipital lobe (t(10) = -3.757, p = 0.004), with no changes after 0.4 ng/kg (p > 0.05). Group-by time interactions revealed decreased NAA in the left Rolandic operculum in FM (t(13) = 2.664, p = 0.019), but not in HCs (p > 0.05). A dose-by-time interaction showed decreased NAA in the left paracentral lobule after 0.3 ng/kg (t(9) = 3.071, p = 0.013) but not after 0.4 ng/kg (p > 0.05). In the combined sample, there was a main effect of time whereby NAA decreased in the left anterior cingulate (F[1,21] = 4.458, p = 0.047) and right parietal lobe (F[1,21] = 5.457, p = 0.029).

Conclusion

We found temperature increases and NAA decreases in FM that were not seen in HCs, suggesting that FM patients may have abnormal immune responses in the brain. The 0.3 and 0.4 ng/kg had differential effects on brain temperature and metabolites, with neither dose effecting a stronger response overall. There is insufficient evidence provided by the study to determine whether FM involves abnormal central responses to low-level immune challenges.

Altered Tumor Necrosis Factor Response in Neurologic Postacute SARS-CoV-2 Syndrome

Neurologic manifestations of postacute sequelae after SARS-CoV-2 infection (neuro-PASC) are common; however, the underlying drivers of those symptoms remain poorly understood. Prior work has postulated that immune dysregulation leads to ongoing neuroinflammation. We aimed to identify the cytokines involved in that immune dysregulation by comparing 37 plasma cytokine profiles among 20 case patients with neuro-PASC to 20 age- and gender-matched controls. Neuro-PASC cases were defined as individuals with self-reported persistent headache, general malaise, and anosmia or ageusia at least 28 days post-SARS-CoV-2 infection. As a sensitivity analysis, we repeated the main analysis among only participants of Hispanic heritage. In total, 40 specimens were tested. Participants were an average of 43.5 years old (interquartile range 30-52), 20 (50.0%) of whom identified as women. Levels of tumor necrosis factor alpha (TNFα) were 0.76 times lower [95% confidence interval (CI) 0.62-0.94] among cases of neuro-PASC compared with controls, as were levels of C-C motif chemokine 19 (CCL19) (0.67; 95% CI 0.50-0.91), C-C motif chemokine 2 (CCL2) (0.72; 95% CI 0.55-0.95), chemokine interferon-gamma inducible protein 10 (CXCL10) (0.63; 95% CI 0.42-0.96), and chemokine interferon-gamma inducible protein 9 (CXCL9) (0.62; 95% CI 0.38-0.99). Restricting analysis of TNF and CCL19 to participants who identified as Hispanic did not alter results. We noted a reduction in TNFα and down-stream chemokines among patients with neuro-PASC, suggesting an overall immune attenuation.

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature

Some patients remain unwell for months after "recovering" from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars. In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

A Proposed New Model to Explain the Role of Low Dose Non-DNA Targeted Radiation Exposure in Chronic Fatigue and Immune Dysfunction Syndrome

Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS) is considered to be a multidimensional illness whose etiology is unknown. However, reports from Chernobyl, as well as those from the United States, have revealed an association between radiation exposure and the development of CFIDS. As such, we present an expanded model using a systems biology approach to explain the etiology of CFIDS as it relates to this cohort of patients. This paper proposes an integrated model with ionizing radiation as a suggested trigger for CFIDS mediated through UVA induction and biophoton generation inside the body resulting from radiation-induced bystander effects (RIBE). Evidence in support of this approach has been organized into a systems view linking CFIDS illness markers with the initiating events, in this case, low-dose radiation exposure. This results in the formation of reactive oxygen species (ROS) as well as important immunologic and other downstream effects. Furthermore, the model implicates melanoma and subsequent hematopoietic dysregulation in this underlying process. Through the identification of this association with melanoma, clinical medicine, including dermatology, hematology, and oncology, can now begin to apply its expansive knowledge base to provide new treatment options for an illness that has had few effective treatments.

Towards a Better Understanding of the Complexities of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Long COVID

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition arising in susceptible people, predominantly following viral infection, but also other stressful events. The susceptibility factors discussed here are both genetic and environmental although not well understood. While the dysfunctional physiology in ME/CFS is becoming clearer, understanding has been hampered by different combinations of symptoms in each affected person. A common core set of mainly neurological symptoms forms the modern clinical case definition, in the absence of an accessible molecular diagnostic test. This landscape has prompted interest in whether ME/CFS patients can be classified into a particular phenotype/subtype that might assist better management of their illness and suggest preferred therapeutic options. Currently, the same promising drugs, nutraceuticals, or behavioral therapies available can be beneficial, have no effect, or be detrimental to each individual patient. We have shown that individuals with the same disease profile exhibit unique molecular changes and physiological responses to stress, exercise and even vaccination. Key features of ME/CFS discussed here are the possible mechanisms determining the shift of an immune/inflammatory response from transient to chronic in ME/CFS, and how the brain and CNS manifests the neurological symptoms, likely with activation of its specific immune system and resulting neuroinflammation. The many cases of the post viral ME/CFS-like condition, Long COVID, following SARS-CoV-2 infection, and the intense research interest and investment in understanding this condition, provide exciting opportunities for the development of new therapeutics that will benefit ME/CFS patients.

Post-COVID syndrome, inflammation, and diabetes

The raging COVID-19 pandemic is in its third year of global impact. The SARS CoV 2 virus has a high rate of spread, protean manifestations, and a high morbidity and mortality in individuals with predisposing risk factors. The pathophysiologic mechanisms involve a heightened systemic inflammatory state, cardiometabolic derangements, and varying degrees of glucose intolerance. The latter can be evident as significant hyperglycemia leading to new-onset diabetes or worsening of preexisting disease. Unfortunately, the clinical course beyond the acute phase of the illness may persist in the form of a variety of symptoms that together form the so-called "Long COVID" or "Post-COVID Syndrome". It is thought that a chronic, low-grade inflammatory and immunologic state persists during this phase, which may last for weeks or months. Although numerous insights have been gained into COVID-related hyperglycemia and diabetes, its prediction, course, and management remain to be fully elucidated.

Associations of unspecified pain, idiopathic pain and COVID-19 in South Korea: a nationwide cohort study

Background

Few studies have investigated unspecified or idiopathic pain associated with COIVD-19. This study aimed to provide the incidence rates of unspecified pain and idiopathic pain in patients with COVID-19 for 90 days after COVID-19 diagnosis.

Methods

A propensity score matched cohort was used, including all patients with COVID-19 in South Korea, and analyzed their electronic medical records. The control group consisted of those who had not had tests for COVID-19 at all. Unspecified pain diagnoses consisted of diagnoses related to pain included in the ICD-10 Chapter XVIII. Idiopathic pain disorders included fibromyalgia, temporomandibular joint disorders, headaches, chronic prostatitis, complex regional pain syndrome, atypical facial pain, irritable bowel syndrome, and interstitial cystitis.

Results

After matching, the number of participants in each group was 7,911. For most unspecified pain, the incidences were higher in the COVID-19 group (11.7%; 95% confidence interval [CI], 11.0–12.5) than in the control group (6.5%; 95% CI, 6.0–7.1). For idiopathic pain, only the headaches had a significantly higher incidence in the COVID-19 group (6.6%; 95% CI, 6.1–7.2) than in the control group (3.7%; 95% CI, 3.3–4.1). However, using a different control group that included only patients who visited a hospital at least once for any reasons, the incidences of most unspecified and idiopathic pain were higher in the control group than in the COVID-19 group.

Conclusions

Patients with COVID-19 might be at a higher risk of experiencing unspecified pain in the acute phase or after recovery compared with individuals who had not had tests for COVID-19.

A randomized, double-blind, placebo-controlled, hybrid parallel-arm study of low-dose naltrexone as an adjunctive anti-inflammatory treatment for major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is a leading cause of disability worldwide. The current treatments are ineffective in approximately one-third of patients, resulting in a large economic burden and reduced quality of life for a significant proportion of the global population. There is considerable evidence that increased inflammation may distinguish a sub-type of MDD, and there are no validated diagnostic tools or treatments for neuroinflammation in MDD patients. The current study aims to explore the potential role of low-dose naltrexone (LDN), a drug with purported anti-inflammatory properties in the central nervous system, as an adjunctive treatment in patients with MDD.

METHODS/DESIGN

This double-blind placebo-controlled hybrid parallel arm study enables the exploration of peripheral and central inflammatory markers with LDN as an approach to investigate inflammation as a pathophysiological contributor to MDD. Eligible participants with MDD (n = 48) will be stratified into the high and low inflammatory groups according to the levels of high-sensitivity C-reactive protein (hs-CRP) and then randomized to receive LDN or placebo for an initial 12 weeks, followed by a further 12 weeks during which all participants will receive LDN. The primary outcome measure will be the Montgomery-Åsberg Depression Rating Scale (MADRS) administered at baseline, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 14 weeks, 16 weeks, 20 weeks, and 24 weeks, to assess the effectiveness of the anti-depressant response. The secondary outcomes include the use of MRI techniques including quantitative magnetization transfer (qMT), echo-planar spectroscopic imaging (EPSI), and diffusion-weighted imaging (DWI) to help to elucidate the neurobiological mechanism of LDN, and the inflammatory mechanisms in action in MDD. Electroencephalography, blood samples, cognitive tasks, and additional questionnaires will also be used to determine if there is a specific profile of symptoms in individuals with inflammatory MDD. Healthy participants (n = 24) will be recruited for baseline outcome measures only, to enable comparison with patients with MDD.

DISCUSSION

This trial contributes to the literature on inflammation in MDD, including the understanding of the pathophysiology and efficacy of anti-inflammatory treatments. The investigation of inflammatory mechanisms in MDD is an important first step in the development of biomarkers to classify patient sub-groups, increase the accuracy of diagnosis, and tailor the approach to patients in clinical practice. This study may provide evidence of the benefit of LDN for the groups in whom conventional anti-depressants are ineffective and lead the way for translation into clinical practice.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12622000881730 . Registered on 21 June 2022.

Neurological Complications of COVID-19 in the Elderly

SARS-CoV-2 virus is a β-coronavirus and produces a severe viral pneumonia which can be complicated by acute respiratory distress syndrome and multiorgan failure. As knowledge of the new coronavirus infection (COVID-19) increases, it has become known that SARS-CoV-2 has pronounced neurotropism, producing a wide spectrum of neurological complications. This article addresses the characteristics of the neurological complications of COVID-19 in elderly people.

The Link Between Energy-Related Sensations and Metabolism: Implications for Treating Fatigue

Energy-related sensations include sensation of energy and fatigue as well as subjective energizability and fatigability. First, we introduce interdisciplinary useful definitions of all constructs and review findings regarding the question of whether sensations of fatigue and energy are two separate constructs or two ends of a single dimension. Second, we describe different components of the bodily energy metabolism system (e.g., mitochondria; autonomic nervous system). Third, we review the link between sensation of fatigue and different components of energy metabolism. Finally, we present an overview of different treatments shown to affect both energy-related sensations and metabolism before outlining future research perspectives.

Molecular Mechanisms of Neuroinflammation in ME/CFS and Long COVID to Sustain Disease and Promote Relapses

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disease now well-documented as having arisen commonly from a viral infection, but also from other external stressors, like exposure to agricultural chemicals, other types of infection, surgery, or other severe stress events. Research has shown these events produce a systemic molecular inflammatory response and chronic immune activation and dysregulation. What has been more difficult to establish is the hierarchy of the physiological responses that give rise to the myriad of symptoms that ME/CFS patients experience, and why they do not resolve and are generally life-long. The severity of the symptoms frequently fluctuates through relapse recovery periods, with brain-centered symptoms of neuroinflammation, loss of homeostatic control, "brain fog" affecting cognitive ability, lack of refreshing sleep, and poor response to even small stresses. How these brain effects develop with ME/CFS from the initiating external effector, whether virus or other cause, is poorly understood and that is what our paper aims to address. We propose the hypothesis that following the initial stressor event, the subsequent systemic pathology moves to the brain via neurovascular pathways or through a dysfunctional blood-brain barrier (BBB), resulting in chronic neuroinflammation and leading to a sustained illness with chronic relapse recovery cycles. Signaling through recognized pathways from the brain back to body physiology is likely part of the process by which the illness cycle in the peripheral system is sustained and why healing does not occur. By contrast, Long COVID (Post-COVID-19 condition) is a very recent ME/CFS-like illness arising from the single pandemic virus, SARS-CoV-2. We believe the ME/CFS-like ongoing effects of Long COVID are arising by very similar mechanisms involving neuroinflammation, but likely with some unique signaling, resulting from the pathology of the initial SARS-CoV-2 infection. The fact that there are very similar symptoms in both ongoing diseases, despite the diversity in the nature of the initial stressors, supports the concept of a similar dysfunctional CNS component common to both.

Brain temperature as an indicator of neuroinflammation induced by typhoid vaccine: Assessment using whole-brain magnetic resonance spectroscopy in a randomised crossover study

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MRSI-derived whole-brain temperature did not detect low-level neuroinflammation.

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Regional brain temperature was a more sensitive measure of neuroinflammation.

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MRSI/EPSI might be a useful measure of neuroinflammation in psychiatric disorders.

Prior studies indicate a pathogenic role of neuroinflammation in psychiatric disorders; however, there are no accepted methods that can reliably measure low-level neuroinflammation non-invasively in these individuals. Magnetic resonance spectroscopic imaging (MRSI) is a versatile, non-invasive neuroimaging technique that demonstrates sensitivity to brain inflammation. MRSI in conjunction with echo-planar spectroscopic imaging (EPSI) measures brain metabolites to derive whole-brain and regional brain temperatures, which may increase in neuroinflammation. The validity of MRSI/EPSI for measurement of low level neuroinflammation was tested using a safe experimental model of human brain inflammation – intramuscular administration of typhoid vaccine. Twenty healthy volunteers participated in a double-blind, placebo-controlled crossover study including MRSI/EPSI scans before and 3 h after vaccine/placebo administration. Body temperature and mood, assessed using the Profile of Mood States, were measured every hour up to four hours post-treatment administration. A mixed model analysis of variance was used to test for treatment effects. A significant proportion of brain regions (44/47) increased in temperature post-vaccine compared to post-placebo (p < 0.0001). For temperature change in the brain as a whole, there was no significant treatment effect. Significant associations were seen between mood scores assessed at 4 h and whole brain and regional temperatures post-treatment. Findings indicate that regional brain temperature may be a more sensitive measure of low-level neuroinflammation than whole-brain temperature. Future work where these measurement techniques are applied to populations with psychiatric disorders would be of clinical interest.

The Pathobiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Case for Neuroglial Failure

Although myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has a specific and distinctive profile of clinical features, the disease remains an enigma because causal explanation of the pathobiological matrix is lacking. Several potential disease mechanisms have been identified, including immune abnormalities, inflammatory activation, mitochondrial alterations, endothelial and muscular disturbances, cardiovascular anomalies, and dysfunction of the peripheral and central nervous systems. Yet, it remains unclear whether and how these pathways may be related and orchestrated. Here we explore the hypothesis that a common denominator of the pathobiological processes in ME/CFS may be central nervous system dysfunction due to impaired or pathologically reactive neuroglia (astrocytes, microglia and oligodendrocytes). We will test this hypothesis by reviewing, in reference to the current literature, the two most salient and widely accepted features of ME/CFS, and by investigating how these might be linked to dysfunctional neuroglia. From this review we conclude that the multifaceted pathobiology of ME/CFS may be attributable in a unifying manner to neuroglial dysfunction. Because the two key features - post exertional malaise and decreased cerebral blood flow - are also recognized in a subset of patients with post-acute sequelae COVID, we suggest that our findings may also be pertinent to this entity.

Post COVID fatigue: Can we really ignore it?

Long-COVID, also referred to as post-acute COVID-19, chronic COVID-19, post-COVID syndrome, or post-acute sequelae of SARS-CoV-2 infection (PASC), generally refers to symptoms that develop during or after acute COVID-19 illness, continue for ≥12 weeks, and are not explained by an alternative diagnosis. It is not yet known whether "long-COVID" represents a new syndrome unique to COVID-19 or overlaps with recovery from similar illnesses. It's difficult for physicians to predict when symptoms will improve as it varies differently in different people. Patient's recovery depends on various factors including age, associated comorbidities, severity of COVID-19 infection. Some symptoms, like fatigue, might continue even while others improve or go away. This review addresses the pathogenesis, presentation of post covid fatigue, its severity and its management.

Perspective: Drawing on Findings From Critical Illness to Explain Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

We propose an initial explanation for how myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) could originate and perpetuate by drawing on findings from critical illness research. Specifically, we combine emerging findings regarding (a) hypoperfusion and endotheliopathy, and (b) intestinal injury in these illnesses with our previously published hypothesis about the role of (c) pituitary suppression, and (d) low thyroid hormone function associated with redox imbalance in ME/CFS. Moreover, we describe interlinkages between these pathophysiological mechanisms as well as “vicious cycles” involving cytokines and inflammation that may contribute to explain the chronic nature of these illnesses. This paper summarizes and expands on our previous publications about the relevance of findings from critical illness for ME/CFS. New knowledge on diagnostics, prognostics and treatment strategies could be gained through active collaboration between critical illness and ME/CFS researchers, which could lead to improved outcomes for both conditions.

Low Tissue Creatine: A Therapeutic Target in Clinical Nutrition

Low tissue creatine characterizes many conditions, including neurodegenerative, cardiopulmonary, and metabolic diseases, with a magnitude of creatine shortfall often corresponds well to a disorder’s severity. A non-invasive monitoring of tissue metabolism with magnetic resonance spectroscopy (MRS) might be a feasible tool to evaluate suboptimal levels of creatine for both predictive, diagnostic, and therapeutic purposes. This mini review paper summarizes disorders with deficient creatine levels and provides arguments for assessing and employing tissue creatine as a relevant target in clinical nutrition.

COVID-19 and chronic fatigue syndrome: An endocrine perspective

Patients recovering from COVID-19 may have persistent debilitating symptoms requiring long term support through individually tailored cardiopulmonary and psychological rehabilitation programs. Clinicians need to be aware about the likely long-term complications and their diagnostic assessments to help identify any occult problems requiring additional help. Endocrinological evaluations should be considered as part of the armamentarium in the management of such individuals with diligent cognizance about the involvement of the hypothalamo-pituitary-adrenal (HPA) axis, adrenal and thyroid function. We here review the literature and potential pathophysiological mechanisms involved in and related to post COVID-19 symptoms with an emphasis on endocrine function.

A Natural History of Disease Framework for Improving the Prevention, Management, and Research on Post-viral Fatigue Syndrome and Other Forms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

We propose a framework for the treatment, rehabilitation, and research into Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) using a natural history of disease approach to outline the distinct disease stages, with an emphasis on cases following infection to provide insights into prevention. Moving away from the method of subtyping patients based on the various phenotypic presentations and instead reframing along the lines of disease progression could help with defining the distinct stages of disease, each of which would benefit from large prospective cohort studies to accurately describe the pathological mechanisms taking place therein. With a better understanding of these mechanisms, management and research can be tailored specifically for each disease stage. Pre-disease and early disease stages call for management strategies that may decrease the risk of long-term morbidity, by focusing on avoidance of further insults, adequate rest to enable recovery, and pacing of activities. Later disease stages require a more holistic and tailored management approach, with treatment-as this becomes available-targeting the alleviation of symptoms and multi-systemic dysfunction. More stringent and standardised use of case definitions in research is critical to improve generalisability of results and to create the strong evidence-based policies for management that are currently lacking in ME/CFS.

Chronic fatigue syndrome and cognitive deficit are associated with acute-phase neuropsychiatric manifestations of COVID-19: A 9-month follow-up study

The preva lence of long-COVID symptoms is rising but it is not still possible to predict which patients will present them, and which types of symptoms they will present. We followed up 95 patients with confirmed COVID-19 for 9 months to identify and characterize long-COVID symptoms. Easy fatigability was the most common symptom (51.04%), followed by anxiety (38.54%), dyspnea (38.54%), and new-onset headache (38.54%). There was no association between COVID-19 severity in the acute phase and the number of long-COVID symptoms (F(1,93) = 0.75, p = 0.45), and cognitive function (MoCA) scores (F(1,90) = 0.073, p = 0.787) at follow-up. Being female (F(1,92) =  − 2.27, p = 0.02), having a higher number of symptoms (F(1,93) = 2.76, p = 0.0068), and experiencing constitutional neuropsychiatric symptoms (F(1,93) = 2.529, p = 0.01) in the acute phase were associated with having chronic fatigue syndrome at follow-up. Moreover, constitutional neuropsychiatric symptoms in the acute phase were associated with a lower MoCA score (F(1,93) = 10.84, p = 0.001) at follow-up. Specific clinical presentations such as constitutional neuropsychiatric symptoms in the acute phase might be predictors of debilitating long-COVID symptoms such as chronic fatigue syndrome and cognitive deficits.

Neurochemical abnormalities in chronic fatigue syndrome: a pilot magnetic resonance spectroscopy study at 7 Tesla

RATIONALE

Chronic fatigue syndrome (CFS) is a common and burdensome illness with a poorly understood pathophysiology, though many of the characteristic symptoms are likely to be of brain origin. The use of high-field proton magnetic resonance spectroscopy (MRS) enables the detection of a range of brain neurochemicals relevant to aetiological processes that have been linked to CFS, for example, oxidative stress and mitochondrial dysfunction.

METHODS

We studied 22 CFS patients and 13 healthy controls who underwent MRS scanning at 7 T with a voxel placed in the anterior cingulate cortex. Neurometabolite concentrations were calculated using the unsuppressed water signal as a reference.

RESULTS

Compared to controls, CFS patients had lowered levels of glutathione, total creatine and myo-inositol in anterior cingulate cortex. However, when using N-acetylaspartate as a reference metabolite, only myo-inositol levels continued to be significantly lower in CFS participants.

CONCLUSIONS

The changes in glutathione and creatine are consistent with the presence of oxidative and energetic stress in CFS patients and are potentially remediable by nutritional intervention. A reduction in myo-inositol would be consistent with glial dysfunction. However, the relationship of the neurochemical abnormalities to the causation of CFS remains to be established, and the current findings require prospective replication in a larger sample.

No Signs of Neuroinflammation in Women With Chronic Fatigue Syndrome or Q Fever Fatigue Syndrome Using the TSPO Ligand [11C]-PK11195

Background and Objectives

The pathophysiology of chronic fatigue syndrome (CFS) and Q fever fatigue syndrome (QFS) remains elusive. Recent data suggest a role for neuroinflammation as defined by increased expression of translocator protein (TSPO). In the present study, we investigated whether there are signs of neuroinflammation in female patients with CFS and QFS compared with healthy women, using PET with the TSPO ligand ¹¹C-(R)-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carbox-amide ([¹¹C]-PK11195).

Methods

The study population consisted of patients with CFS (n = 9), patients with QFS (n = 10), and healthy subjects (HSs) (n = 9). All subjects were women, matched for age (±5 years) and neighborhood, aged between 18 and 59 years, who did not use any medication other than paracetamol or oral contraceptives, and were not vaccinated in the last 6 months. None of the subjects reported substance abuse in the past 3 months or reported signs of underlying psychiatric disease on the Mini-International Neuropsychiatric Interview. All subjects underwent a [¹¹C]-PK11195 PET scan, and the [¹¹C]-PK11195 binding potential (BP_ND) was calculated.

Results

No statistically significant differences in BP_ND were found for patients with CFS or patients with QFS compared with HSs. BP_ND of [¹¹C]-PK11195 correlated with symptom severity scores in patients with QFS, but a negative correlation was found in patients with CFS.

Discussion

In contrast to what was previously reported for CFS, we found no significant difference in BP_ND of [¹¹C]-PK11195 when comparing patients with CFS or QFS with healthy neighborhood controls. In this small series, we were unable to find signs of neuroinflammation in patients with CFS and QFS.

Trial Registration Information

EudraCT number 2014-004448-37.

Lessons From Heat Stroke for Understanding Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

We here provide an overview of the pathophysiological mechanisms during heat stroke and describe similar mechanisms found in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Both conditions are characterized by disturbed homeostasis in which inflammatory pathways play a central role. Splanchnic vasoconstriction, increased gut permeability, gut-related endotoxemia, systemic inflammatory response, central nervous system dysfunction, blood coagulation disorder, endothelial-cell injury, and mitochondrial dysfunction underlie heat stroke. These mechanisms have also been documented in ME/CFS. Moreover, initial transcriptomic studies suggest that similar gene expressions are altered in both heat stroke and ME/CFS. Finally, some predisposing factors for heat stroke, such as pre-existing inflammation or infection, overlap with those for ME/CFS. Notwithstanding important differences - and despite heat stroke being an acute condition - the overlaps between heat stroke and ME/CFS suggest common pathways in the physiological responses to very different forms of stressors, which are manifested in different clinical outcomes. The human studies and animal models of heat stroke provide an explanation for the self-perpetuation of homeostatic imbalance centered around intestinal wall injury, which could also inform the understanding of ME/CFS. Moreover, the studies of novel therapeutics for heat stroke might provide new avenues for the treatment of ME/CFS. Future research should be conducted to investigate the similarities between heat stroke and ME/CFS to help identify the potential treatments for ME/CFS.

Orthostatic Symptoms and Reductions in Cerebral Blood Flow in Long-Haul COVID-19 Patients: Similarities with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Background and Objectives: Symptoms and hemodynamic findings during orthostatic stress have been reported in both long-haul COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), but little work has directly compared patients from these two groups. To investigate the overlap in these clinical phenotypes, we compared orthostatic symptoms in daily life and during head-up tilt, heart rate and blood pressure responses to tilt, and reductions in cerebral blood flow in response to orthostatic stress in long-haul COVID-19 patients, ME/CFS controls, and healthy controls. Materials and Methods: We compared 10 consecutive long-haul COVID-19 cases with 20 age- and gender-matched ME/CFS controls with postural tachycardia syndrome (POTS) during head-up tilt, 20 age- and gender-matched ME/CFS controls with a normal heart rate and blood pressure response to head-up tilt, and 10 age- and gender-matched healthy controls. Identical symptom questionnaires and tilt test procedures were used for all groups, including measurement of cerebral blood flow and cardiac index during the orthostatic stress. Results: There were no significant differences in ME/CFS symptom prevalence between the long-haul COVID-19 patients and the ME/CFS patients. All long-haul COVID-19 patients developed POTS during tilt. Cerebral blood flow and cardiac index were more significantly reduced in the three patient groups compared with the healthy controls. Cardiac index reduction was not different between the three patient groups. The cerebral blood flow reduction was larger in the long-haul COVID-19 patients compared with the ME/CFS patients with a normal heart rate and blood pressure response. Conclusions: The symptoms of long-haul COVID-19 are similar to those of ME/CFS patients, as is the response to tilt testing. Cerebral blood flow and cardiac index reductions during tilt were more severely impaired than in many patients with ME/CFS. The finding of early-onset orthostatic intolerance symptoms, and the high pre-illness physical activity level of the long-haul COVID-19 patients, makes it unlikely that POTS in this group is due to deconditioning. These data suggest that similar to SARS-CoV-1, SARS-CoV-2 infection acts as a trigger for the development of ME/CFS.

Brainstem Abnormalities in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Scoping Review and Evaluation of Magnetic Resonance Imaging Findings

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multisystem medical condition with heterogeneous symptom expression. Currently, there is no effective cure or treatment for the standard care of patients. A variety of ME/CFS symptoms can be linked to the vital life functions of the brainstem, the lower extension of the brain best known as the hub relaying information back and forth between the cerebral cortex and various parts of the body. Objective/Methods: Over the past decade, Magnetic Resonance Imaging (MRI) studies have emerged to understand ME/CFS with interesting findings, but there has lacked a synthesized evaluation of what has been found thus far regarding the involvement of the brainstem. We conducted this study to review and evaluate the recent MRI findings via a literature search of the MEDLINE database, from which 11 studies met the eligibility criteria. Findings: Data showed that MRI studies frequently reported structural changes in the white and gray matter. Abnormalities of the functional connectivity within the brainstem and with other brain regions have also been found. The studies have suggested possible mechanisms including astrocyte dysfunction, cerebral perfusion impairment, impaired nerve conduction, and neuroinflammation involving the brainstem, which may at least partially explain a substantial portion of the ME/CFS symptoms and their heterogeneous presentations in individual patients. Conclusions: This review draws research attention to the role of the brainstem in ME/CFS, helping enlighten future work to uncover the pathologies and mechanisms of this complex medical condition, for improved management and patient care.

[Chronic fatigue syndrome against the background of the COVID-19 pandemic]

The more we learn about the new coronavirus infection, the more we understand that we will feel the echoes of the pandemic for many years, and those who have successfully endured the acute phase of COVID-19 may face the consequences of the infection. One of the most frequent manifestations will be the development of chronic fatigue syndrome (CFS) after COVID-19. This article discusses the possible causes of the development of CFS, as well as possible ways of its treatment and prevention.

[Neurological complications of COVID-19 in elderly people]

Virus SARS-CoV2 (beta-coronavirus) can induce severe pneumonia with acute respiratory distress syndrome, respiratory failure and multiorgan dysfunction. As more we learned about Covid-19, we understand that SARS-CoV-2 have neuroinvasive properties and can cause different neurological complications. In this article we discusses about the features of neurological sequences of Covid-19 in elderly people.

Limbic Perfusion Is Reduced in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an illness characterized by a diverse range of debilitating symptoms including autonomic, immunologic, and cognitive dysfunction. Although neurological and cognitive aberrations have been consistently reported, relatively little is known regarding the regional cerebral blood flow (rCBF) in ME/CFS. In this study, we studied a cohort of 31 ME/CSF patients (average age: 42.8 ± 13.5 years) and 48 healthy controls (average age: 42.9 ± 12.0 years) using the pseudo-continuous arterial spin labeling (PCASL) technique on a whole-body clinical 3T MRI scanner. Besides routine clinical MRI, the protocol included a session of over 8 min-long rCBF measurement. The differences in the rCBF between the ME/CSF patients and healthy controls were statistically assessed with voxel-wise and AAL ROI-based two-sample t-tests. Linear regression analysis was also performed on the rCBF data by using the symptom severity score as the main regressor. In comparison with the healthy controls, the patient group showed significant hypoperfusion (uncorrected voxel wise p ≤ 0.001, FWE p ≤ 0.01) in several brain regions of the limbic system, including the anterior cingulate cortex, putamen, pallidum, and anterior ventral insular area. For the ME/CFS patients, the overall symptom severity score at rest was significantly associated with a reduced rCBF in the anterior cingulate cortex. The results of this study show that brain blood flow abnormalities in the limbic system may contribute to ME/CFS pathogenesis.

Network Analysis of Symptoms Co-Occurrence in Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is a heterogenous disorder of multiple disabling symptoms with complex manifestations. Network analysis is a statistical and interrogative methodology to investigate the prevalence of symptoms (nodes) and their inter-dependent (inter-nodal) relationships. In the present study, we explored the co-occurrence of symptoms in a cohort of Polish CFS patients using network analysis. A total of 110 patients with CFS were examined (75 females). The mean age of the total sample was 37.93 (8.5) years old while the mean duration of symptoms in years was 4.4 (4). Post-exertional malaise (PEM) was present in 75.45% of patients, unrefreshing sleep was noted in 89.09% and impaired memory or concentration was observed in 87.27% of patients. The least prevalent symptom was tender cervical or axillary lymph nodes, noted in 34.55% of the total sample. Three of the most densely connected nodes were the total number of symptoms, sore throat and PEM. PEM was positively related with impairment in memory or concentration. Both PEM and impairment in memory or concentration presence are related to more severe fatigue measured by CFQ and FIS. PEM presence was positively related with the presence of multi-joint pain and negatively with tender lymph nodes and muscle pain. Sore throat was related with objective and subjective autonomic nervous system impairment. This study helps define symptom presentation of CFS with the pathophysiology of specific systems and links with multidisciplinary contemporary molecular pathology, including comparative MRI.

Insights from myalgic encephalomyelitis/chronic fatigue syndrome may help unravel the pathogenesis of postacute COVID-19 syndrome

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause chronic and acute disease. Postacute sequelae of SARS-CoV-2 infection (PASC) include injury to the lungs, heart, kidneys, and brain that may produce a variety of symptoms. PASC also includes a post-coronavirus disease 2019 (COVID-19) syndrome ('long COVID') with features that can follow other acute infectious diseases and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Here we summarize what is known about the pathogenesis of ME/CFS and of 'acute' COVID-19, and we speculate that the pathogenesis of post-COVID-19 syndrome in some people may be similar to that of ME/CFS. We propose molecular mechanisms that might explain the fatigue and related symptoms in both illnesses, and we suggest a research agenda for both ME/CFS and post-COVID-19 syndrome.

Induced pluripotent stem cells as suitable sensors for fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND

Fibromyalgia (FM) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are devastating metabolic neuroimmune diseases that are difficult to diagnose because of the presence of numerous symptoms and a lack of specific biomarkers. Despite patient heterogeneity linked to patient subgroups and variation in disease severity, anomalies are found in the blood and plasma of these patients when compared with healthy control groups. The seeming specificity of these “plasma factors”, as recently reported by Ron Davis and his group at Stanford University, CA, United States, and observations by our group, have led to the proposal that induced pluripotent stem cells (iPSCs) may be used as metabolic sensors for FM and ME/CFS, a hypothesis that is the basis for this in-depth review.

AIM

To identify metabolic signatures in FM and/or ME/CFS supporting the existence of disease-associated plasma factors to be sensed by iPSCs.

METHODS

A PRISMA (Preferred Reported Items for Systematic Reviews and Meta-analysis)-based systematic review of the literature was used to select original studies evaluating the metabolite profiles of FM and ME/CFS body fluids. The MeSH terms “metabolomic” or “metabolites” in combination with FM and ME/CFS disease terms were screened against the PubMed database. Only original studies applying omics technologies, published in English, were included. The data obtained were tabulated according to the disease and type of body fluid analyzed. Coincidences across studies were searched and P-values reported by the original studies were gathered to document significant differences found in the disease groups.

RESULTS

Eighteen previous studies show that some metabolites are commonly altered in ME/CFS and FM body fluids. In vitro cell-based assays have the potential to be developed as screening platforms, providing evidence for the existence of factors in patient body fluids capable of altering morphology, differentiation state and/or growth patterns. Moreover, they can be further developed using approaches aimed at blocking or reversing the effects of specific plasma/serum factors seen in patients. The documented high sensitivity and effective responses of iPSCs to environmental cues suggests that these pluripotent cells could form robust, reproducible reporter systems of metabolic diseases, including ME/CFS and FM. Furthermore, culturing iPSCs, or their mesenchymal stem cell counterparts, in patient-conditioned medium may provide valuable information to predict individual outcomes to stem-cell therapy in the context of precision medicine studies.

CONCLUSION

This opinion review explains our hypothesis that iPSCs could be developed as a screening platform to provide evidence of a metabolic imbalance in FM and ME/CFS.

Redox imbalance links COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome

Although most patients recover from acute COVID-19, some experience postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC). One subgroup of PASC is a syndrome called "long COVID-19," reminiscent of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS is a debilitating condition, often triggered by viral and bacterial infections, leading to years-long debilitating symptoms including profound fatigue, postexertional malaise, unrefreshing sleep, cognitive deficits, and orthostatic intolerance. Some are skeptical that either ME/CFS or long COVID-19 involves underlying biological abnormalities. However, in this review, we summarize the evidence that people with acute COVID-19 and with ME/CFS have biological abnormalities including redox imbalance, systemic inflammation and neuroinflammation, an impaired ability to generate adenosine triphosphate, and a general hypometabolic state. These phenomena have not yet been well studied in people with long COVID-19, and each of them has been reported in other diseases as well, particularly neurological diseases. We also examine the bidirectional relationship between redox imbalance, inflammation, energy metabolic deficits, and a hypometabolic state. We speculate as to what may be causing these abnormalities. Thus, understanding the molecular underpinnings of both PASC and ME/CFS may lead to the development of novel therapeutics.

A Paradigm for Post-Covid-19 Fatigue Syndrome Analogous to ME/CFS

A significant proportion of COVID-19 patients are suffering from prolonged Post-COVID-19 Fatigue Syndrome, with characteristics typically found in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). However, no clear pathophysiological explanation, as yet, has been provided. A novel paradigm for a Post-COVID-19 Fatigue Syndrome is developed here from a recent unifying model for ME/CFS. Central to its rationale, SARS-CoV-2, in common with the triggers (viral and non-viral) of ME/CFS, is proposed to be a physiologically severe stressor, which could be targeting a stress-integrator, within the brain: the hypothalamic paraventricular nucleus (PVN). It is proposed that inflammatory mediators, released at the site of COVID-19 infection, would be transmitted as stress-signals, via humoral and neural pathways, which overwhelm this stress-center. In genetically susceptible people, an intrinsic stress-threshold is suggested to be exceeded causing ongoing dysfunction to the hypothalamic PVN's complex neurological circuitry. In this compromised state, the hypothalamic PVN might then be hyper-sensitive to a wide range of life's ongoing physiological stressors. This could result in the reported post-exertional malaise episodes and more severe relapses, in common with ME/CFS, that perpetuate an ongoing disease state. When a certain stress-tolerance-level is exceeded, the hypothalamic PVN can become an epicenter for microglia-induced activation and neuroinflammation, affecting the hypothalamus and its proximal limbic system, which would account for the range of reported ME/CFS-like symptoms. A model for Post-COVID-19 Fatigue Syndrome is provided to stimulate discussion and critical evaluation. Brain-scanning studies, incorporating increasingly sophisticated imaging technology should enable chronic neuroinflammation to be detected, even at a low level, in the finite detail required, thus helping to test this model, while advancing our understanding of Post-COVID-19 Fatigue Syndrome pathophysiology.

The Enterovirus Theory of Disease Etiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Critical Review

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex, multi-system disease whose etiological basis has not been established. Enteroviruses (EVs) as a cause of ME/CFS have sometimes been proposed, as they are known agents of acute respiratory and gastrointestinal infections that may persist in secondary infection sites, including the central nervous system, muscle, and heart. To date, the body of research that has investigated enterovirus infections in relation to ME/CFS supports an increased prevalence of chronic or persistent enteroviral infections in ME/CFS patient cohorts than in healthy individuals. Nevertheless, inconsistent results have fueled a decline in related studies over the past two decades. This review covers the aspects of ME/CFS pathophysiology that are consistent with a chronic enterovirus infection and critically reviews methodologies and approaches used in past EV-related ME/CFS studies. We describe the prior sample types that were interrogated, the methods used and the limitations to the approaches that were chosen. We conclude that there is considerable evidence that prior outbreaks of ME/CFS were caused by one or more enterovirus groups. Furthermore, we find that the methods used in prior studies were inadequate to rule out the presence of chronic enteroviral infections in individuals with ME/CFS. Given the possibility that such infections could be contributing to morbidity and preventing recovery, further studies of appropriate biological samples with the latest molecular methods are urgently needed.

Possible involvement of the autonomic nervous system in cervical muscles of patients with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS)

Background

Patients with myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) sometimes present with stiffness of the cervical muscles. To investigate the pathophysiology of ME/CFS, this observational study compared patients with versus without recovery from ME/CFS through local modulation of the cervical muscles.

Methods

Over a period of 11 years, a total of 1226 inpatients with ME/CFS who did not respond to outpatient care were enrolled in this study. All patients received daily cervical muscle physical therapy during hospitalization. Self-rated records documenting the presence or absence of ME/CFS, as well as the representative eight symptoms that frequently accompany it at admission and discharge, were compared. Pupil diameter was also measured to examine autonomic nervous system function involvement.

Results

The recovery rate of ME/CFS after local therapy was 55.5%, and did not differ significantly by sex, age strata, and hospitalization period. The recovery rates of the eight symptoms were variable (36.6–86.9%); however, those of ME/CFS in the symptom subpopulations were similar (52.3–55.8%). The recovery rates of all symptoms showed strong associations with that of ME/CFS (p < 0.001). The pupil diameter was more constricted in the ME/CFS-recovered patients than in the ME/CFS-unrecovered patients in the total population and the subpopulations stratified by sex, age, and hospitalization period.

Conclusions

There was a strong association between the recovery of ME/CFS and other related whole-body symptoms. The recovery of ME/CFS may be partly linked to amelioration of the autonomic nervous system in the cervical muscles.

Trial registration

UMIN000036634. Registered 1 May 2019 - Retrospectively registered.

Investigating whole-brain metabolite abnormalities in the chronic stages of moderate or severe traumatic brain injury

BACKGROUND

Evidence suggests that neurometabolic abnormalities can persist after traumatic brain injury (TBI) and drive clinical symptoms such as fatigue and cognitive disruption. Magnetic resonance spectroscopy has been used to investigate metabolite abnormalities following TBI, but few studies have obtained data beyond the subacute stage or over large brain regions.

OBJECTIVE

To measure whole-brain metabolites in chronic stages of TBI.

DESIGN

Observational study.

SETTING

University.

PARTICIPANTS

Eleven men with a moderate or severe TBI more than 12 months prior and 10 age-matched healthy controls completed whole-brain spectroscopic imaging.

MAIN MEASURES

Ratios of N-acetylaspartate (NAA), choline (CHO), and myo-inositol (MI) to creatine (CR) were measured in whole-brain gray and white matter as well as 64 brain regions of interest. Arterial spin labeling (ASL) data were also collected to investigate whether metabolite abnormalities were accompanied by differences in cerebral perfusion.

RESULTS

There were no differences in metabolite ratios within whole-brain gray and white matter regions of interest (ROIs). Linear regression showed lower NAA/CR in the white matter of the left occipital lobe but higher NAA/CR in the gray matter of the left parietal lobe. Metabolite abnormalities were observed in several brain regions in the TBI group including the corpus callosum, putamen, and posterior cingulate. However, none of the findings survived correction for multiple comparison. There were no differences in cerebral blood flow between patients and controls.

CONCLUSION

Higher MI/CR may indicate ongoing gliosis, and it has been suggested that low CHO/CR at chronic time points may indicate cell death or lack of healthy turnover and repair. However, with the small sample size of this study, we caution against the overinterpretation of our results. None of the findings within ROIs survived correction for multiple comparison. Thus, they may be considered possible avenues for future research in this area.

Dysautonomia: A Forgotten Condition - Part 1

Dysautonomia covers a range of clinical conditions with different characteristics and prognoses. They are classified as Reflex Syndromes, Postural Orthostatic Tachycardia Syndrome (POTS), Chronic Fatigue Syndrome, Neurogenic Orthostatic Hypotension (nOH) and Carotid Sinus Hypersensitivity Syndrome. Reflex (vasovagal) syndromes will not be discussed in this article. Reflex (vasovagal) syndromes are mostly benign and usually occur in patients without an intrinsic autonomic nervous system (ANS) or heart disease. Therefore, they are usually studied separately. Cardiovascular Autonomic Neuropathy (CAN) is the term most currently used to define dysautonomia with impairment of the sympathetic and/or parasympathetic cardiovascular autonomic nervous system. It can be idiopathic, such as multisystemic atrophy or pure autonomic failure, or secondary to systemic pathologies such as diabetes mellitus, neurodegenerative diseases, Parkinson's disease, dementia syndromes, chronic renal failure, amyloidosis and it may also occur in the elderly. The presence of Cardiovascular Autonomic Neuropathy (CAN) implies greater severity and worse prognosis in various clinical situations. Detection of Orthostatic Hypotension (OH) is a late sign and means greater severity in the context of dysautonomia, defined as Neurogenic Orthostatic Hypotension (nOH). It must be differentiated from hypotension due to hypovolemia or medications, called non-neurogenic orthostatic hypotension (nnOH). OH can result from benign causes, such as acute, chronic hypovolemia or use of various drugs. However, these drugs may only reveal subclinical pictures of Dysautonomia. All drugs of patients with dysautonomic conditions should be reevaluated. Precise diagnosis of CAN and the investigation of the involvement of other organs or systems is extremely important in the clinical suspicion of pandysautonomia. In diabetics, in addition to age and time of disease, other factors are associated with a higher incidence of CAN, such poor glycemic control, hypertension, dyslipidemia and obesity. Among diabetic patients, 38-44% can develop Dysautonomia, with prognostic implications and higher cardiovascular mortality. In the initial stages of DM, autonomic dysfunction involves the parasympathetic system, then the sympathetic system and, later on, it presents as orthostatic hypotension. Valsalva, Respiratory and Orthostatic tests (30:15) are the gold standard methods for the diagnosis of CAN. They can be associated with RR Variability tests in the time domain, and mainly in the frequency domain, to increase the sensitivity (protocol of the 7 tests). These tests can detect initial or subclinical abnormalities and assess severity and prognosis. The Tilt Test should not be the test of choice for investigating CAN at an early stage, as it detects cases at more advanced stages. Tilt response with a dysautonomic pattern (gradual drop in blood pressure without increasing heart rate) may suggest CAN. Treatment of patients at moderate to advanced stages of dysautonomia is quite complex and often refractory, requiring specialized and multidisciplinary evaluation. There is no cure for most types of Dysautonomia at a late stage. NOH patients can progress with supine hypertension in more than 50% of the cases, representing a major therapeutic challenge. The immediate risk and consequences of OH should take precedence over the later risks of supine hypertension and values greater than 160/90 mmHg are tolerable. Sleeping with the head elevated (20-30 cm), not getting up at night, taking short-acting antihypertensive drugs for more severe cases, such as losartan, captopril, clonidine or nitrate patches, may be necessary and effective in some cases. Preventive measures such as postural care; good hydration; higher salt intake; use of compression stockings and abdominal straps; portioned meals; supervised physical activity, mainly sitting, lying down or exercising in the water are important treatment steps. Various drugs can be used for symptomatic nOH, especially fludrocortisone, midodrine and droxidopa, the latter not available in Brazil. The risk of exacerbation or triggering supine hypertension should be considered. Chronic Fatigue Syndrome represents a form of Dysautonomia and has been renamed as a systemic disease of exercise intolerance, with new diagnostic criteria: 1 - Unexplained fatigue, leading to occupational disability for more than 6 months; 2 - Feeling ill after exercising; 3 - Non-restorative sleep; 4 - One of the following findings: cognitive impairment or orthostatic intolerance. Several pathologies today have evolved with chronic fatigue, being called chronic diseases associated with chronic fatigue. Postural orthostatic tachycardia syndrome (POTS), another form of presentation of dysautonomic syndromes, is characterized by sustained elevation of heart rate (HR) ≥30 bpm (≥40 bpm if <20 years) or HR ≥120 bpm, in the first 10 minutes in an orthostatic position or during the tilt test, without classical orthostatic hypotension associated. A slight decrease in blood pressure may occur. Symptoms appear or get worse in an orthostatic position, with dizziness, weakness, pre-syncope, palpitations, and other systemic symptoms being common.